{Description}
{Title of Invention}
AIR CLEANING APPARATUS AND METHOD FOR PREDICTING BREAKTHROUGH
TIME FOR THE SAME
{Technical Field}
{0001}
The present invention relates to an air cleaning apparatus
including a filtering portion to remove a poisonous gas in
atmospheres and a method of predicting a breakthrough time for
the same.
{Background}
{0002}
There has been known an air cleaning apparatus such as a
mask including a filtering portion, as a constitutional element,
that filters air contaminated or polluted with a poisonous gas,
wherein the filtering portion removes the poisonous gas to clean
the air. Also, there has been known a gas mask, which is one
of air cleaning apparatuses that detects the concentration of
a poisonous gas included in the air after passing through the
filtering portion by a sensor, provided on a downstream side of
the filtering portion in the gas mask. There has been known
an air cleaning apparatus that can estimate a residual
breakthrough time of the filtering portion by estimating a

degree of breakthrough progress of a filtering member of the
filtering portion. Further, there has been known an air
cleaning apparatus that is capable of predicting a life span
of the filtering portion in accordance with variation in a flow
rate of air contaminated with a poisonous gas passing through
the filtering portion or variation in humidity of the air.
{0003}
For example, a protective mask described in JP 2006-263238A
(PTL 1) includes a semiconductor odor sensor that can estimate
a time of replacement for a canister, disposed on the downstream
side of the canister.
{0004}
In a filtering replacement time discriminating apparatus
described in JP 1991-207425A (PTL 2), a first gas sensor is
provided on the upstream side of a filter so as to measure a
concentration of molecule of unnecessary gases such as a gas
having an offensive odor in the outside air. A second gas sensor
and an anemometer are provided on the downstream side of the
filter. A difference between the molecular concentration of
the unnecessary gas CI detected by the first gas sensor and the
molecular concentration of the unnecessary gas C2 detected by
the second gas sensor is calculated, and an amount of airflow
Q per unit time to be processed through the filter is calculated

using the anemometer as well. An amount of removal of the
unnecessary gas through the filter is calculated based on CI,
C2, and Q, and a judgment is made by comparing the amount of
removal with a limit removal offensive gas amount at which the
filter deteriorates, so that it can be determined whether the
breakthrough time is left.
{0005}
Also, an air cleaning apparatus described in JP 2007-117859A
(PTL 3) includes a flow rate detector to detect a flow rate of
air passing through a gas filter and a humidity detector to
detect the humidity of the air passing through the gas filter,
calculates an amount of exhaustion of the gas filter based on
the detected data from each detector, and predicts a residual
amount of the gas filter based on the amount of exhaustion. The
residual amount of the gas filter indicates the residual amount
of the breakthrough time of the filtering member.
{Citation List}
{Patent Literature}
{0006}
{PTL 1}JP 2006-263238A
{PTL 2}JP 1991-207425A
{PTL 3}JP 2007-117859A
{Summary}

{Technical Problem}
{0007}
The apparatus described in PTL 1 is configured to detect
the concentration of a hydrogen sulfide gas on the downstream
side of the canister by a semiconductor odor sensor element and
issue an alarm when the concentration is high, so that the
apparatus cannot detect the life span of the canister that is
varied according to the work environment.
{0008}
In the apparatus described in PTL 2, the first gas sensor
cannot predict the reduction of the breakthrough time of the
filter when the molecular concentration of the unnecessary gas
in the outside air is high. Also, the second gas sensor provided
on the downstream side of the filter, for example, on the inner
side of the gas mask, tends to become larger in size when its
precision is high, and there has been a problem in that the gas
mask wearer's field of vision is obstructed, and work is
hampered. Also, in the apparatus, the judgment on a magnitude
is made by comparing the amount of removal with the limit removal
offensive gas amount at which the filter deteriorates, so that
it is difficul to judge in stages the state of deterioration
of the filter.
{0009}

The apparatus described in PTL 3 is useful when the
concentration of poisonous gas element in the outside air is
constant. However, when the concentration of the poisonous gas
is varied along with a lapse of time, this apparatus cannot be
used. Also, regarding humidity that affects the exhaustion of
the gas filter, a breakthrough characteristic curve of the gas
filter with regard to the humidity on three levels is
exemplified. However, when the breakthrough characteristic of
the gas filter is substantially varied due to the humidity,
there is a case where a dependence on only breakthrough
characteristic curves to be exemplified lacks an accuracy of
a judgment on the filtering replacement time. Accordingly, in
order to deal with this case, it is necessary to acquire a
magnitude of breakthrough characteristic curves that clarifies
the influence of the humidity, that is, to produce a data map
having a large capacity.
{0010}
Further, when the temperature of the air contaminated with
the poisonous gas is varied, these conventional technologies
do not provide a means to be dealt with. Accordingly, when the
breakthrough characteristic of the filtering member is varied
due to the temperature, information obtained through these
conventional technologies might lack an accuracy.

{0011}
The present invention has been achieved in view of the above
circumstances to solve the problems, and it is an object of the
present invention to provide an air cleaning apparatus that is
capable of predicting a breakthrough time of a filtering portion
and a method of predicting a breakthrough time for the apparatus
even if the concentration of a poisonous gas included in air
on the upstream side of the filtering portion, the flow rate
of the air passing through the filtering portion, the
temperature of the air, and the humidity of the air are changed.
{Solution to Problem}
{0012}
In order to solve this problem, the present invention
includes the invention according to an air cleaning apparatus
and the invention according to a method of predicting a
breakthrough time for the air cleaning apparatus.
{0013}
The present invention including an air cleaning apparatus
may provide an air cleaning apparatus that includes a filtering
portion to allow air contaminated with a poisonous gas to pass
through from an upstream side to a downstream side so as to remove
the poisonous gas, and configured to be capable of predicting
a breakthrough time during which concentration of the poisonous

gas on the downstream side of the filtering portion reaches
breakthrough concentration, which is arbitrarily set with
respect to the concentration of the poisonous gas.
{0014}
The present invention including the air cleaning apparatus
further includes the following features:
the air cleaning apparatus may further include an arithmetic
processing unit configured to input data on the concentration
of the poisonous gas in the air on the upstream side of the
filtering portion, a flow rate of the air passing through the
filtering portion, a temperature of the air on the upstream side,
and relative humidity of the air on the upstream side; and
it may be configured such that a breakthrough-time
prediction formula in which the concentration of the poisonous
gas included in the air on the upstream side of the filtering
portion used in the air cleaning apparatus, the flow rate, the
temperature, and the relative humidity are provided as
variables is programmed in the arithmetic processing unit, and
the breakthrough time is predictable by the prediction formula
based on the data.
{0015}
According to an embodiment of the present invention including
the air cleaning apparatus, in the arithmetic processing unit,

the prediction formula may be formulated prior to use of the
air cleaning apparatus, based on a reference condition that is
constituted by the concentration of the poisonous gas included
in the air on the upstream side, the flow rate, the temperature,
the relative humidity, and the breakthrough concentration, and
on the breakthrough time measured under the reference
condition.
{0016}
According to another embodiment of the present invention
including the air cleaning apparatus, the arithmetic processing
unit may correct the breakthrough time of the reference
condition for the filtering portion, based on the temperature
and the relative humidity.
{0017}
According to another embodiment of the present invention
including the air cleaning apparatus, the air cleaning
apparatus may include at least one of a detector of the
concentration of the poisonous gas, a detector of the flow rate,
a detector of the temperature, and a detector of the relative
humidity.
{0018}
According to another embodiment of the present invention
including the air cleaning apparatus, the detector for any item

of the data, out of the data on the concentration of the poisonous
gas in the air on the upstream side of the filtering portion,
the blow rate, the temperature, and relative humidity, is not
used when the item has a constant value during use of the air
cleaning apparatus.
{0019}
According to another embodiment of the present invention
including the air cleaning apparatus, the arithmetic processing
unit may be used in a cordless state.
{0020}
According to another embodiment of the present invention
including the air cleaning apparatus, at least one item of the
data, out of the data on the concentration of the poisonous gas
included in the air on the upstream side of the filtering portion,
the flow rate, the temperature, and the relative humidity, may
be input to the arithmetic processing unit by radio.
{0021}
According to another embodiment of the present invention
including the air cleaning apparatus, the poisonous gas is a
reference gas provided as a toxic gas to be arbitrarily selected,
and concentration of the reference gas on the upstream side is
represented as Co (ppm), and the flow rate is represented as
Q (L/min), and the breakthrough concentration is represented

as S (ppm) , and a time during which concentration of the
reference gas on the downstream side reaches S (ppm) is the
breakthrough time, and wherein the prediction formula is
represented by a formula below,
breakthrough time = reference breakthrough time ×
concentration variation ratio × flow rate variation ratio ×
temperature variation ratio × humidity variation ratio ×
breakthrough concentration variation ratio;
reference breakthrough time: a duration time during which
the concentration on the downstream side of the filtering
portion reaches A%, which is a value that is less than 100% and
arbitrarily set as the breakthrough concentration with respect
to the concentration Co, in a case where the concentration Co,
the flow rate Q, the temperature T, and the relative humidity
RH are kept constant;
concentration variation ratio: a correction coefficient
with respect to concentration variation calculated by obtaining
the reference breakthrough times for the concentration Co at
least on two levels while the flow rate, the temperature, and
the humidity are kept constant;
flow rate Variation ratio: a correction coeficisnt witn
respect to flow rate variation calculated by obtaining the
reference breakthrough times for the flow rate Q at least on

two levels while the concentration, the temperature, and the
humidity are kept constant;
temperature variation ratio: a correction coefficient with
respect to temperature variation calculated by obtaining the
reference breakthrough times for the temperature T at least on
two levels while the concentration, the flow rate, and the
relative humidity are kept constant;
humidity variation ratio: a correction coefficient with
respect to. humidity variation calculated by obtaining the
reference breakthrough times for at least two levels including
one level at which a level of the relative humidity RH is equal
to or higher than 50% while the concentration, the flow rate,
and the temperature are kept constant;
breakthrough concentration variation ratio: a correction
coefficient with respect to breakthrough concentration
variation calculated by obtaining an A% breakthrough time
corresponding to the breakthrough concentration A% obtained
with respect to the flow rates Q at least on three levels, and
a B% breakthrough time corresponding to breakthrough
concentration B% that is different from the breakthrough
concentration A% on one level of flow rate Q while the
concentration, the temperature, and the humidity are kept
constant.

{0022}
According to another embodiment of the present invention
including the air cleaning apparatus, the formula according to
the embodiment of the present invention is represented by
formulas (1) and (2) described below,
(1) in a case of the relative humidity RH ≥ 50%,
breakthrough time = 1 / reference breakthrough time x (C0a
× 10b) × (c × 1 / Q + d) × (i × EXP j × Q × Ln (S / CD × 100) +
1) × (e × RH + f) × (g × T + h);
(2) in a case of the relative humidity RH < 50%,
breakthrough time = 1 / reference breakthrough time × (Coa
× 10b) × (c × 1 / Q + d) × (i × EXP j × Q × Ln (S / C0 × 100) +
1) × (g × T + h); and
in the formulas (1) and (2) above,
reference breakthrough time: a duration time during which
the concentration on the downstream side reaches A%, which is
a value that is less than 100% and arbitrarily set with respect
to the concentration C0, in a case where the concentration C0,
the flow rate Q, the temperature T, and the relative humidity
RH are kept constant;
RH: relative humidity (%);

a, b: constants obtained based on the concentration C0 at
least on two levels and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration CD with
regard to each concentration C0 while the flow rate Q, the
temperature T, and the relative humidity RH are kept constant;
c, d: constants obtained based on the flow rates Q at least
on two levels and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration C0 with
regard to each flow rate Q while the concentration C0, the
temperature T, and the relative humidity RH are kept constant;
e, f: constants obtained based on at least two levels
including one level at which a level of the relative humidity
RH is equal to or higher than 50%, and a breakthrough time during
which the concentration of the poisonous gas on the downstream
side of the filtering portion reaches A% of the- concentration
C0 with regard to each relative humidity RH while the
concentration C0, the flow rate Q, and the temperature T are
kept constant;
g, h: constants obtained based on temperatures at least on
two levels, and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of

the filtering portion reaches A% of the concentration C0 with
regard to each temperature T while the concentration C0, the
flow rate Q, and the relative humidity RH are kept constant;
i, j : constants obtained based on the A% breakthrough times
and the flow rates Q in a case where the flow rate Q is changed
at least on three levels, and the B% breakthrough time using
one level out of the three levels of flow rate Q at which the
A% breakthrough time is obtained, while the concentration Co,
the temperature T, . and the relative humidity RH are kept
constant.
{0023}
According to another embodiment of the present invention
including the air cleaning apparatus, the arithmetic processing
unit may be programmed in such a manner that the breakthrough
time is calculated by using a relative bieakthrough ratio with
respect to the reference gas of the poisonous gas.
{0024}
According to another embodiment of the present invention
including the air cleaning apparatus, correction based on a
dissolution rate in water in a case where the poisonous gas is
I
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II a j-it^uiu oc_a.i_c _LO lliauc -i.O±. pj-cuii^LXun OJ_ LIIC i_>j_ ca JS. LiiJ_ w uy ii
time for which the relative breakthrough ratio is used.
{0025}

According to another embodiment of the present invention
including the air cleaning apparatus, in the arithmetic
processing unit, a degree of breakthrough progress per unit time
with respect to the filtering portion can be obtained, and the
breakthrough time of the filtering portion is calculated by
multiplying the degree of breakthrough progress.
{0026}
According to another embodiment of the present invention
including the air cleaning apparatus, a time ranging from 1/6000
to 5/600 min may be used for the unit time.
{0027}
According to another embodiment of the present invention
including the air cleaning apparatus, the arithmetic processing
unit can calculate at least one of a residual breakthrough time
and a residual use ratio with respect to the filtering portion.
{0028}
According to another embodiment of the present invention
including the air cleaning apparatus, the air cleaning
apparatus may be made up of any of a gas mask and a local exhaust
device.
{0029}
According to another embodiment of the present invention
including the air cleaning apparatus, the detector of the flow

rate may be arranged in any of the upstream side and the
downstream side of the filtering portion in the gas mask.
{0030}
According to another embodiment of the present invention
including the air cleaning apparatus, the detector of the flow
rate may be arranged in any of the upstream side and the
downstream side of the filtering portion in the local exhaust
device.
{0031}
The present invention including a method for predicting a
breakthrough time for the air cleaning apparatus may provide
a method, in a case where air contaminated with a poisonous gas
passes through a filtering portion of an air cleaning apparatus
from an upstream side to a downstream side, for predicting a
breakthrough time until concentration of the poisonous gas on
the downstream side of the filtering portion reaches
breakthrough concentration, which is arbitrarily set with
respect to the concentration of the poisonous gas.
{0032}
Also, the present invention including the method for
prsiaicuing tus oreaKuhrougix time is characterize^ as IOHOWS .
That is, in the air cleaning apparatus, data on the
concentration of the poisonous gas included in the air on the

upstream side of the filtering portion, a flow rate of the air
passing through the filtering portion, a temperature of the air
on the upstream side, and relative humidity of the air on the
upstream side, may be input-to an arithmetic processing unit,
and in the arithmetic processing unit, the breakthrough time
is calculated based on the data and a breakthrough-time
prediction formula programmed in the arithmetic processing unit,
where the concentration of the poisonous gas included in the
air on the upstream side, the flow rate, the temperature, and
the relative humidity are provided as variables.
{0033}
According to one embodiment of the present invention
including the method for predicting the breakthrough time, the
breakthrough-time prediction formula may be formulated in the
arithmetic processing unit prior to use of the air cleaning
apparatus, based on a reference condition that is constituted
by the concentration of the poisonous gas included in the air
on the upstream side, the flow rate, the temperature, the
relative humidity, and the breakthrough concentration, and on
the breakthrough time measured under the reference condition.
{0034}
According to another embodiment of the present invention
including the method for predicting the breakthrough time, the

arithmetic processing unit may correct the breakthrough time
of the reference condition for the filtering portion, based on
the temperature and the relative humidity.
{0035}
According to another embodiment of the present invention
including the method for predicting the breakthrough time, the
poisonous gas is a reference gas provided as a toxic gas to be
arbitrarily selected, and concentration of the reference gas
on the upstream side is. represented as C0 (ppm) , and the flow
rate is represented as Q (L/min) , and the breakthrough
concentration is represented as S (ppm)', and a time during which
concentration of the reference gas on the downstream side
reaches S (ppm) is the breakthrough time, and wherein the
prediction formula is represented by a formula below,
breakthrough time = reference breakthrough time *
concentration variation ratio * flow rate variation ratio *
temperature variation ratio x humidity variation ratio x
breakthrough concentration variation ratio;
reference breakthrough time: a duration time during which
the concentration on the downstream side of the filtering
jjuiLXun ICQUUCO n'o , wiiJ-ou xo a Vaiuc mat J_O J_C^>O L-iicui IUU'O cuiia
arbitrarily set as the breakthrough concentration with respect
to the concentration CQ, in a case where the concentration C0,

the flow rate Q, the temperature T, and the relative humidity
RH are kept constant;
concentration variation ratio: a correction coefficient
with respect to concentration variation calculated by obtaining
the reference breakthrough times for the concentrations C0 at
least on two levels while the flow rate, the temperature, and
the humidity are kept constant;
flow rate variation ratio: a correction coefficient with
respect to flow rate variation calculated by obtaining the
reference breakthrough times for the flow rates Q at least on
two levels while the concentration, the temperature, and the
humidity are kept constant;
temperature variation ratio: a correction coefficient with
respect to temperature variation calculated by obtaining the
reference breakthrough times for the temperatures T at least
on two levels while the concentration, the flow rate, and the
relative humidity are kept constant;
humidity variation ratio: a correction coefficient with
respect to humidity variation calculated by obtaining the
reference breakthrough time for at least two levels including
one level at which a level of the relative humidity RH is equal
to or higher than 50% while the concentration, the flow rate,
and the temperature are kept constant;

breakthrough concentration variation ratio: a correction
coefficient with respect to breakthrough concentration
variation calculated by obtaining an A% breakthrough time
corresponding to the breakthrough concentration A%- obtained
with respect to the flow rates Q at least on three levels, and
a B% breakthrough time corresponding to breakthrough
concentration B% that is different from the breakthrough
concentration A% on one level of flow rate Q while the
concentration, the temperature, and the humidity are kept
constant.
{0036}
According to another embodiment of the present invention
including the method for predicting the breakthrough time, the
formula according to the one of the embodiments is represented
by formulas (1) and (2) described below,
(1) in a case of the relative humidity RH ^ 50%,
breakthrough time = 1 / reference breakthrough time * (Coa
x 10b) x (c x l / Q + d) x (i x EXP j * Q x Ln (S / CQ * 100) +
1) x (e x RH + f) x (g x T + h) ;
(2) in a case of the relative humidity RH < 50%,
x 10b) x (c x 1 / Q + d) x (i x EXP j x Q x Ln (S / C0 x 100) +
1) x (g x T + h); and

in the formulas (1) and (2) above,
reference breakthrough time: a duration time during which
the concentration on the downstream side reaches A%, which is
a value that is less than 100% and arbitrarily set with respect
to the concentration Co, in a case where the concentration Co,
the flow rate Q, the temperature T, and the relative humidity
RH are kept constant;
T: temperature (°C);
RH: relative humidity (%);
a, b: constants obtained based on the concentrations Co at
least on two levels and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration Co with
regard to each concentration Co while the flow rate Q, the
temperature T, and the relative humidity RH are kept constant;
c, d: constants obtained based on the flow rates Q at least
on two levels and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration Co with
regard to each flow rate Q while the concentration Co, the
temperature T, and the relative humidity RH are kept constant;
e, f: constants obtained based on at least two levels
including one level at which a level of the relative humidity

RH is equal to or higher than 50%, and a breakthrough time during
which the concentration of the poisonous gas on the downstream
side of the filtering portion reaches A% of the concentration
Co with regard to each relative humidity RH while the
concentration Co, the flow rate Q, and the temperature T are
kept constant;
g, h: constants obtained based on temperatures at least on
two levels, and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration Co with
regard to each temperature T while the concentration Co, the
flow rate Q, and the relative humidity RH are kept constant;
i, j : constants obtained based on an A% breakthrough time
and the flow rate Q in a case where the flow rate Q is changed
at least on three levels, and a B% breakthrough time on one level
out of the three levels of the flow rate Q at which the A%
breakthrough time is obtained, while the concentration Co, the
temperature T, and the relative humidity RH are kept constant.
{0037}
According to another embodiment of the present invention
_l_ 11W _i_ U.Li_i_liy L-ll^. ALL^. UllO <^L ±. W J_ pJ-UU-L^I L1J.V.J LliC JJJ-CaiVLllJ-UUUlJ. t HUC ^ L-ilC
arithmetic processing unit may be programmed in such a manner
that the breakthrough time can also be calculated by using a

relative breakthrough ratio of the poisonous gas with respect
to the reference gas.
{0038}
According to another embodiment of the present invention
including the method for predicting the breakthrough time,
correction based on a dissolution rate in water in a case where
the poisonous gas is in a liquid state may be made for the
calculation of the breakthrough time for which the relative
breakthrough ratio is used.
{0039}
In the present invention, by "breakthrough" of
"breakthrough time" is meant that when the air contaminated with
the poisonous gas passes through the filtering portion, the
concentration of the poisonous gas in the air after passing
through the filtering portion reaches concentration equal to
or higher than concentration that is set to an arbitrary value.
The concentration set to the arbitrary value is referred to as
"breakthrough concentration" . Also, by "breakthrough time" is
meant a service life after which the filtering portion reaches
"breakthrough".
10040}
In the present invention, by "threshold value" is meant a
gas concentration to the extent that causes health impairment

when a human continues to inhale a poisonous gas having a certain
degree of gas concentration for a uniform period of time.
{Solution to Problem}
{0041}
According to the embodiment of the present invention, the
air cleaning apparatus measures the concentration of the
poisonous gas on the upstream side of the filtering portion,
even if the space on the downstream side of the filtering portion
is limited, a large-size sensor with high precision to measure
the concentration can be used.
{0042}
The air cleaning apparatus calculates and predicts the
breakthrough time based on a breakthrough-time calculation
formula in which the concentration of the poisonous gas in the
air on the upstream side of the filtering portion, the
temperature of the air, the humidity of the air, and the flow
rate of the air passing through the filtering portion are
correlated, so that the breakthrough time can exactly be
calculated even if the any one of the concentration of the
poisonous gas on the upstream side of the filtering portion,
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Luc ucui^ciaL,uic anu iiuuLL_L^_L u_y OL uiic CLA.±. r aliv^i LilC ilUW J_dL.C Ul
the air passing through the filtering portion is changed during
the use of the air cleaning apparatus. It is meant that, when

the filtering portion is a canister, the life span of the
canister can exactly be calculated.
{0043}
Also, for example, in the case where the air cleaning
apparatus is a gas mask, the threshold value is applied for
breakthrough concentration, and the measurement intervals of
each measuring portion are shortened, so that, even when the
concentration of the poisonous gas in the air on the upstream
side of the filtering portion, the temperature of the air, and
the humidity of the air are changed in a short interval of time,
or the flow rate of the air passing through the filtering portion
is changed from one minute to the next along with the breathing
of the wearer, not only can the breakthrough time be calculated
with high precision, but also can the breakthrough time be
calculated by calculating the degree of breakthrough progress
that corresponds to relentless changes in the flow rate, which
is attributed to the breathing which the gas mask wearer takes.
Also, according to such features, the filtering capacity of the
filtering element may be utilized effectively.
{Brief Description of Drawings}
{0044}
{Fig. 1} Fig. 1 is a perspective view of an air cleaning
apparatus.

{Fig. 2} Fig. 2 is a partial cross-sectional enlarged view taken
along line II-II in Fig. 1.
{Fig. 3} Fig. 3 is a schematic diagram illustrating a device
to observe a breakthrough time of a gas mask.
{Fig. 4} Fig. 4 is a graph illustrating a relation between test
concentration and 1% breakthrough time.
{Fig. 5} Fig. 5 is a graph illustrating a relation between a
flow rate and the 1% breakthrough time.
{Fig. 6} Fig. 6 is a graph illustrating a relation between a
temperature and the 1% breakthrough time.
{Fig. 7} Fig. 7 is a graph illustrating a relation between
relative humidity and the 1%. breakthrough time.
{Fig. 8} Fig. 8 is a graph illustrating a relation between an
observation time and the concentration on a downstream side.
{Fig. 9} Fig. 9 is a graph illustrating a relation between %
breakthrough time and % breakthrough concentration influence
ratio (flow rate).
{Fig. 10} Fig. 10 is a graph illustrating a state where a gradient
of a straight line changes in accordance with the flow rate.
{Fig. 11} Fig. 11 is a graph illustrating variation in a flow
rate of inhalation and exhalation.
{Fig. 12} Fig. 12 is a cross-sectional view of a local exhaust
device according to an embodiment of the present invention.

{Fig. 13} Fig. 13 is a diagram according to an embodiment of
the present invention.
{Description of Embodiments}
{0045}
Hereinafter, an air cleaning apparatus according to the
present invention will be described in detail by referring to
the attached drawings.
{0046}
Fig. 1 is a perspective view of a gas mask 1 of the air
cleaning apparatus according to an embodiment of the present
invention. The gas mask 1 includes a facepiece 2 that covers
nostrils and the mouth of a mask wearer (not shown) , a filtering
portion 3 that is replaceably attached and disposed forward of
the facepiece 2, and a strap 4 that extends backward from the
facepiece 2 and worn around the head of the wearer. The
facepiece 2 includes a cylindrical portion 6 that extends
forward of the mask 1 in the left direction of a double-headed
arrow Z. The filtering portion 3 is arranged on a front end
portion of the cylindrical portion 6 . A peripheral edge portion
7 of the facepiece 2 tightly contacts to the wearer's face when
the mask 1 is worn. The filtering portion 3 includes a grid
portion 8 for breathability at the front surface part thereof,
and a multiplicity of air passages 9 are formed in the grid

portion 8. One example of the filtering portion 3 to be used
includes a canister that is demountably formed on the
cylindrical portion 6. It should be noted that the cylindrical
portion 6 is expediently formed to connect the filtering portion
3 to the facepiece 2 but not indispensable in the mask 1.
{0047}
The mask 1 also includes a concentration measuring unit 21
arranged on the outer side of the mask 1 and in the vicinity
of the filtering portion 3 in order to measure the concentration
of the poisonous gases such as cyclohexane and toluene present
in the ambient air 40, a flow rate measuring unit 22 that
penetrates from the outer side of the mask 1 into the inside
of the cylindrical portion 6, a temperature measuring unit 23
to measure a temperature of the air 40, and a humidity measuring
unit 24 to measure humidity of the air 40. As for the measuring
units 21, 22, 23, and 24, sensors 21a, 22a (see Fig. 2), 23a,
and 24a are electrically connected to an arithmetic processing
unit 25 via respectively communication wires 21b, 22b, 23b, and
24b. The arithmetic processing unit 25 is electrically
connected to an alarm 26a via a wire 26b and electrically
connected to a display 27a via a wire 27b. Also, it is possible
to transmit measurement results by radio from the measuring
units 21, 22, 23 and.24 to the arithmetic processing unit 25

or transmit arithmetic results and the like by radio from the
arithmetic processing unit 25 to the alarm 26a and/or the
display 27a.
{0048}
In Fig. 1, a lateral direction, an up-and-down direction,
and a forward-and-backward direction of the mask 1 are shown
by double-headed arrows X, Y, and Z.
{0049}
Fig. 2 is a partial cross-sectional enlarged view taken
along line II - II of Fig. 1, wherein the filtering portion 3
is illustrated in an imaginary line. Also, the filtering
portion 3 which is detached from the cylindrical portion 6 is
illustrated in a side view as a reference. The facepiece 2
includes an inhalation opening 11 and an exhalation opening 12.
A check valve 11a is provided to the inhalation opening 11, and
a check valve 12a is provided to the exhalation opening 12. The
check valve 11a is moved to a position, where the check valve
11a is shown as an imaginary line, by inhalation of the wearer
so as to release the inhalation opening 11. The check valve
12a is moved to a position, where the check valve 12a is shown
as an imaginary line, by exhalation of the wearer so as to release
the exhalation opening 12.
{0050}

The cylindrical portion 6 is arranged in front of the
inhalation opening 11, and includes a small diameter portion
6a connecting with the facepiece 2 and a large diameter portion
6b that is threadedly engaged with the filtering portion 3. The
flow rate measuring unit 22 penetrates into the small diameter
portion 6a via a mounting hole 6c, and the flow rate measuring
sensor 22a is disposed in front of the inhalation opening 11.
The cylindrical portion 6 is provided on the inner peripheral
wall surface of the large diameter portion 6b with threads 6d.
The large diameter portion 6b includes an annular packing 6e
that allows a rear end portion 3b of the filtering portion 3
to be press-contacted airtightly.
{0051}
The filtering portion 3 is filled with a filtering element
3a, which serves as a filter, inside thereof. The filtering
element 3a is formed of materials that are suitable to absorb
at least one specific type of poisonous gas in the air 40. By
"breakthrough time of filtering portion 3" regarding the mask
1 is meant a breakthrough time regarding the filtering element
3a. Threads 3d that are threadedly engaged with the cylindrical
JJOJ.LJ.UII U QLC j.Oi.iucu j_n a UOL-M/VOLU )JUJ.LXUII UI a. jycixyiiCLdX wctJ_a_
3c of the filtering portion 3.
{0052}

Upon inhalation of the wearer who wears the mask 1, the air
40 on the outside of the mask 1 passes through the filtering
portion 3 into the mask 1, and the check valve 11a of the
inhalation opening 11 is opened, which allows the wearer to
inhale. Upon exhalation of the wearer, the check valve 11a is
closed, and the check valve 12a of the exhalation opening 12
is opened, which allows the exhalation of the wearer to be
discharged. When the arithmetic processing unit 25, the
measuring units 21, 22, 23 and 24, the alarm 26a, and the display~
27a are electrically turned on, the sensor 21a of the
concentration measuring unit 21 detects the concentration of
the poisonous gas present in the air 40 penetrating into the
filtering portion 3, and the detection data are transmitted to
the arithmetic processing unit 25. The sensor 23a of the
temperature measuring unit 23 detects the temperature of the
air 40, and the sensor 24a of the humidity measuring unit 24 ~
detects the humidity of the air 40, and the detection data are
transmitted to the arithmetic processing unit 25. In the back
of the cylindrical portion 6, that is, on the downstream side
of the filtering portion 3, the sensor 22a of the flow rate
measuring unit 22, which is arranged in front of the inhalation
opening 11, detects the flow rate of the air 40a that is purified
by absorbing the poisonous gas through the filtering portion

3, and the detection data are transmitted to the arithmetic
processing unit 25. The purified air 40a passes through the
inhalation opening 11 into the facepiece 2 and used as air to
be inhaled.
{0053}
Regarding the filtering portion 3, it has generally been
known that a maximum allowance concentration, which is provided
as a threshold value or a control value with respect to a specific
poisonous gas present in the air 40, is defined as breakthrough
concentration, and the filtering capacity by which the
concentration of the poisonous gas present in the air 40a can
be kept equal to or lower than the threshold value or the control
value is provided as a breakthrough time. It is necessary for
the wearer of the mask 1 to monitor the mask 1 so as to precisely
know the residual amount of the breakthrough time of the
filtering portion 3 and to timely replace the filtering portion
3 in order to avoid an exposure to the poisonous gas due to the
use of the filtering portion 3 used more than the breakthrough
time and to prevent the health impairment.
{0054}
As j-Oi the masK x, witu respect to tne air 4u at a p±ace
where the mask 1 is used, when any of concentration of the
poisonous gas C0, a flow rate Q of the air 40 flown into the

mask 1, a temperature T of the air 40, humidity RH of the air
40 is a constant value, the breakthrough time of the filtering
portion 3 can be measured while obviating the measurement or
the measuring unit with respect to the constant value. For
example, when the flow rate Q, the temperature T, and the
relative humidity RH are constant, the breakthrough time can
be calculated by the mask 1 including only the concentration
measuring unit 21, out of the measuring units 21, 22, 23 and
24. Also, in the environment where only the flow rate Q is
changed, the breakthrough time can be calculated by the mask
1 including only the flow rate measuring unit 22.
{0055}
The mask 1 exemplified in Figs. 1 and 2 facilitates such
management regarding the breakthrough time. The measuring
units 21, 22, 23, and 24, and the arithmetic processing unit
25 are constituted as follows.
{0056}
1. Concentration Measuring Unit 21
(1) The sensor 21a of the concentration measuring unit 21
is placed in a state in such a manner as to come into contact
with the air 40 outside of the mask 1, preferably, in this state
and in a state in such a manner as not to be affected by the
exhalation.

(2) There is no specific provision regarding the sensor 21a,
and. various types of sensors may be used such as a
constant-potential electrolysis type sensor, a PID sensor, a
catalytic combustion type sensor, and an Orgastor type sensor.
As one of concrete embodiments, Mini RAE 3000 (manufactured by
RAE Systems, Inc.) that utilizes the PID sensor can be used as
the concentration measuring unit 21.
{0057}
2. Flow Rate Measuring Unit 22
(1) A flow meter is used in the sensor 22a of the flow rate
measuring unit 22. There is no specific provision regarding
the flow meter, and various types of flow meters can be used
such as a throttle flow meter (Venturi meter), a differential
pressure type flow meter (orifice flow meter), a hot-wire flow
meter, an ultrasonic flow meter, and an impeller flow meter.
It is possible to obtain the flow rate based on an area of a
flow path and a current meter.instead of the flow meter. As
the current meter, various types of current meters can be used
such as a hot-wire current meter, an electromagnetic current
meter, a propeller type current meter, and an ultrasonic type
current in.eL.er.
(2) It is preferable that the sensor 22a be arranged at a
position illustrated in Fig. 2. However, the position can be

changed to an appropriate position where the quantity of airflow
in the filtering portion 3 can substantially be measured.
(3) When an electric fan to supply air to be'breathed in
is used for the mask 1, the flow rate can be obtained based on
a current value or power consumption of the electric fan, the
number of revolutions of a fan motor, and the like, instead of
the use of the sensor 22a.
(4) Also, the opening degrees of the inhalation check valve
11a and the exhalation check valve 12a are detected by a
proximity sensor and the like, and the flow rate is calculated
based on the detection result, which serves as the substitution
for the use of the sensor 22a.
(5) Further, a pressure response element like a diaphragm
is attached on the facepiece 2, and a movement of the response
element is detected by the proximity sensor and the like, and
the flow rate is calculated based on the detected result, which
serves as a substitution for the use of the sensor 22a.
(6) The variation in pressure in the facepiece is measured
by a pressure gauge, and the flow rate is calculated based on
the measurement result, which serves as the substitution for
the use of the sensor 22a.
{0058}
3. Temperature Measuring Unit 23

(1) It is preferable the sensor 23a of the temperature
measuring unit 23 be in a state in such a manner as to come into
contact with the air 40 outside of the mask 1 and be arranged
in the vicinity of the filtering portion 3 and at a position
where the sensor 23a is not affected by the flow of the air 40
flowing to the filtering portion 3 and the flow of air to be
discharged from the exhalation opening 12. However, when the
sensor 23a is a sensor that is not affected by the flow, the
sensor 23a may be arranged in the vicinity of the filtering
portion 3.
(2) There is no specific provision regarding the sensor 23a,
and various types of thermometers can be used, for example, such
as a semiconductor type temperature sensor, a band gap type
temperature sensor, thermocouples, a resistance thermometer
(resistance temperature detector, thermistor), and the like.
{0059}
4. Humidity Measuring Unit 24
(1) It is preferable that the sensor 24a of the humidity
measuring unit 24 be in a state in such a manner as to come into
contact with the air 40, and be arranged at a position where
Lhc o^iiowj. /LICL -L o nOi_ aiicLucu kjy i_nc J_J_OW ui uiie axi. iu diiia
the flow of air to be discharged, as is the same with the sensor
23a. However, when the sensor 24a is a sensor that is not

affected by the flow, the sensor 24a may be arranged in. the
vicinity of the filtering portion 3.
(2) There is no specific provision regarding the sensor 24a,
and various types of hygrometers.can be used, for example, an
electric hygrometer (capacitance type relative humidity sensor,
a high molecular electric resistance type hygrometer, a
ceramics type electric resistance hygrometer, and the like),
a mechanical hygrometer (hair hygrometer), a psychrometer, and
the like.
(3) SHT 75 manufactured by SENSIRION can be used as one
example of the temperature-humidity measuring device including
both the sensor 23a and the sensor 24a.
{0060}
5. Arithmetic Processing Unit 25
(1) As shown in Fig. 1, when the measurement results or
alternative signals in place of the measurement results are
transmitted by wire from the measuring units 21, 22, 23, and 24,
it is preferable that the arithmetic processing unit 25 be on
the lumbar region or the pectoral region of the wearer of the
maskl. Unlike the example shown in Fig. 1, when the measurement
results or the signals are transmitted by radio.from the
measuring units 21, 22, 23 and 24, the arithmetic processing
unit 25 in a cordless state not only allows the wearer to carry

the mask in use, but also allows persons other than the
wearer to know the measurement results from each measuring unit
or arithmetic processing results in a room such as a centralized
control room that is apart from the wearer.
(2) Data can directly be input into the arithmetic
processing unit 25 or indirectly be input from an external
device whose body is separated from the arithmetic processing
unit 25. For example, the arithmetic processing unit 25 has
functions of executing setting of the breakthrough
concentration of a specific poisonous gas in the air 40 in the
filtering portion 3 by inputting the measurement results or the
signals received from the measuring units 21, 22, 23 and 24,
programming of the calculation formula such as a
breakthrough-time prediction formula, calculation of a
prediction breakthrough time based on the breakthrough-time
prediction formula to be programmed, calculation of a degree
of exhaustion of the filtering portion 3 per unit time,
calculation of a residual use available time before the
breakthrough time of the filtering portion 3 reaches that is
obtained based on integration of the degree of exhaustion. When
i-uc j_ c o j- i-t u &J. u.oc a vaj-lauxc L-j-iuc; jjiiui. uu L-ilc; uicarvLiiiOuyli L-J-ILLC
of the filtering portion 3 remains slightly, and attention needs
to be paid to the wearer or a supervisor of the wearer, the

arithmetic processing unit 25 can activate the alarm 26a and
display various arithmetic results in the arithmetic processing
unit 25, the measurement results of the measuring units 21, 22,
23 and 24, and the like on the display 27a. Also, when a name
of a poisonous gas except for the specific poisonous gas or a
relative breakthrough ratio corresponding to the specific
poisonous gas is input, the arithmetic processing unit 25 can
incorporate the input content into the calculation formula such
as the breakthrough-time prediction formula regarding the
specific poisonous gas. By "relative breakthrough ratio" as
referred to in the present invention is meant a value that is
obtained, based on a specific poisonous gas for which the.
breakthrough-time prediction formula is programmed as a
reference gas, by dividing a measured breakthrough time of air
including an arbitrary poisonous gas except for the reference
gas by a measured breakthrough time of air including the
reference gas whose concentration is the same as that of the
arbitrary poisonous gas . Generally well-known poisonous gases
such as cyclohexane and toluene may be selected as the reference
gas. The relative breakthrough ratio may be represented in a
formula 1 below.
(relative breakthrough ratio) = (breakthrough time of
poisonous gas) / (breakthrough time of reference gas) • • •

formula 1
(3) A microcomputer, a personal computer, a sequencer, and
the like can be used for the arithmetic processing unit 25.
{0061}
Fig. 3 is a schematic diagram of a device 100 that can measure
the breakthrough time of the filtering portion 3 of the gas mask
1 in Fig. 1. The device 100 includes a chamber 102 in which
a human-head model 101 wearing the gas mask 1 is disposed, and
an air mixing chamber 105 is provided on an upstream side 102a
of the chamber 102. The air mixing chamber 105 is connected
to a dry air supply line 103, a humidified air supply line 104,
and a poisonous gas supply line 106. A breathing simulator 107
is provided on a downstream side 102b of the chamber 102, and
the human-head model 101 and the breathing simulator 107 are
connected via an airflow pipe 108 . An upstream-side end portion
of the airflow pipe 108 penetrates the human-head model 101 and
reaches the mouth of the human-head model 101. The arithmetic
processing unit 25, the alarm 26a, and the display 27a are
provided on the outside of the chamber 102. The arithmetic
processing unit 25 is electrically connected to the
concentration measuring sensor 21a arranged in the vicinity of
the filtering portion 3 in the inside of the chamber 102, the
temperature measuring sensor 23a, the humidity measuring sensor

24a, the flow rate measuring sensor 22a arranged in the inside
of the gas mask 1.
{0062}
In the dry air supply line 103, dry air is supplied from
a compressor (not shown) to the air mixing chamber 105.
{0063}
In the humidified air supply line 104, the dry air
transferred from the compressor (not shown) passes through
water storage tanks 104a and 104b and turns into humidified air,
which is supplied to the air mixing chamber 105.
{0064}
In the poisonous gas supply line 106, the dry air transferred
from the compressor (not shown) enters the tank 10 6a. For
example, the tank 106a contains liquid cyclohexane, and the dry
air is discharged into the liquid of the cyclohexane, whereby
the liquid of the cyclohexane in the tank 106a vaporizes and
turns into air contaminated with, in other words, polluted with
cyclohexane gas, which is a poisonous gas, and the air is
directed to the air mixing chamber 105.
{0065}
In the air mixing chamber 105, a room temperature is set
to the same temperature as a temperature at which the
breakthrough time or the like is measured. In the air mixing

chamber 105, the dry air, the humidified air, and the air
contaminated with the poisonous gas are mixed so as to include
the poisonous gas having the concentration required to measure
the breakthrough time, whereby turning into the air 40 in which
the temperature and humidity are adjusted to a constant value,
and the air 40 is directed to the chamber 102.
{0066}
The breathing simulator 107 arranged on the downstream side
102b of the chamber 102 can iterate the inhalation operation
and the exhalation operation with the air flow rate adjusted
and change the number of iterations per one minute between the
inhalation operation and the exhalation operation. Further,
the breathing simulator 107 can continuously carry out the
inhalation operation in such a manner as to successively provide
the filtering portion 3 with the air 40 having a constant flow
rate per unit time.
{0067}
In the present invention, the device 100 was used to observe
the breakthrough time of the filtering portion 3 of the gas mask
1, and the cyclohexane was used as the poisonous gas, and an
organic gas canister KVJC-IS ^j-ij-termg element, uaving /8 mm in
diameter and 11.5 mm in thickness) manufactured by Koken Ltd.
was attached as the filtering portion 3 of the gas mask 1 arranged

in the human-head model 101, and a second concentration
detection sensor 21c (see Fig. 2) to detect the concentration
of the poisonous gas contained in the air 40a after passing
through the filtering portion 3 was arranged in the vicinity
of the sensor 22a on the downstream side of the filtering portion
3. In the chamber 102, by detecting the concentration of the
poisonous gas before and after the air 40 containing the
poisonous gas (cyclohexane) having specified concentration
passes through the filtering portion 3, the inventors of the
present invention acquired findings concerning the influence
of the concentration Co of the poisonous gas in the air 40, the
flow rate Q of the air 40 passing through the filtering portion
3, the temperature T of the air 40, and the relative humidity
RH of the air 40 on the breakthrough time BT of the filtering
portion 3 and concerning the prediction of the breakthrough time
BT of the filtering portion 3. It should be noted that the
second concentration detection sensor 21c is electrically
connected to the arithmetic processing unit 25 and its
connection state is illustrated in an imaginary line in Fig.
2. Table 1 shows items for examination on the air 40, and
conditions such as the concentration Co (ppm), the flow rate
Q (L/ min, L : liters), breakthrough reference (%), the
temperature (°C), and the relative humidity (%RH), which are

selected for each item to be examined.
{0068}
{Table 1}

{0069}
Finding 1. Reference conditions (four conditions such as
the concentration Co that was set to an arbitrary value, the
flow rate Q, the temperature T, and the relative humidity RH,
and under the four conditions, a ratio (for example A%) of the
concentration of the poisonous gas leaked out to the downstream
side of the filtering portion 3 to the concentration Co
(hereinafter referred to as % breakthrough concentration or A%
breakthrough concentration) were specified, and the
concentration Co under the reference conditions was changed on
several levels, and on each level, for example, a time during
which % breakthrough concentration (for example A% breakthrough
concentration) reaches 1% breakthrough concentration was
measured, and if the time was assumed as 1% breakthrough time
depending on the concentration (abbreviation: 1% breakthrough
time (concentration) or 1% BTC, or concentration variation
ratio) , 1% BTC tended to be shorter as the level of the
concentration Co increases. Table 2 shows 1% BTC measured on
each level of the concentration Co. Fig. 4 shows a logarithmic
iclaLlun UCLWCCU Luc oun^ciiLiaLiun v,u anu d.S SD±C kjj_ Lilt; xaijj_e
2. This relation regarding concentration variation, that is,
concentration variation ratio may be expressed by mathematical

formulas such as logarithmic approximation, inverse proportion
approximation, power approximation, and the like. As one
example, 1% BTC obtained by the logarithmic approximation is
expressed by a formula 2.
1% BTC = Coa x 10b • • • • • formula 2
a, b : constants experimentally obtained with the
concentration Co at least on two levels
{0070}
{Table 2}

{0071}
Finding 2. The flow rate Q under the reference conditions
was changed on several levels, and on each level, for example,
a time during which % breakthrough concentration reaches 1%
breakthrough concentration was measured. If the time is
assumed as 1% breakthrough time depending on the flow rate

(abbreviation: 1% breakthrough time (flow rate) or 1% BTQ, or
flow rate variation ratio of breakthrough time), 1% BTQ tended
to be shorter as the flow rate Q increased. Table 3 shows 1%
BTQ measured on each level of the flow rate Q. Fig. 5 shows
an inverse proportional relation between the flow rate Q and
1% BTQ of Table 3. This relation regarding flow rate variation,
that is, the flow rate variation ratio may be expressed by-
mathematical formulas such as logarithmic approximation,
inverse proportion approximation, power approximation, and the
like. As one example, 1% BTQ obtained by the inverse proportion
approximation can be expressed by a formula 3.
1% BTQ =cxl/Q+d formula 3
c, d : constants experimentally obtained with the flow rate
Q at least on two levels
{0072}


{0073}
Finding 3. Table 4 shows 1% breakthrough time observed at
a time when the temperature T and the relative humidity %RH were
changed in conditions that the concentration Co was 300 ppm,
and the flow rate Q was 30 L/min. Fig. 6 shows that, when the
concentration Co, the flow rate Q, and relative humidity RH are
constant in Table 4, and the temperature T increases, the
breakthrough time tends to be shorter. The tendency of the
temperature variation, which is linear as shown in Fig. 6, may
be expressed by mathematical formulas. For example, when a
ratio of breakthrough time (hereinafter referred to as a
temperature influence coefficient or a temperature variation
ratio) is obtained based on the breakthrough time at a
temperature of 20 °C as a reference, the temperature influence
coefficient may be expressed by a formula 4.
temperature influence coefficient = g x T + h • • • • • formula
4
g, h : constants experimentally obtained with the
temperature at least on two levels
The formula 4 may be referred to as a temperature correction
formula that is required to calculate the breakthrough time of
the filtering portion 3.
{0074}


{0075}
Finding 4. As is evident in the Table 4, when the
concentration Co, the flow rate Q, and the temperature T were
constant, and the relative humidity RH was equal to or higher
than 50%, the breakthrough time tended to be shorter as the
relative humidity RH increases. The tendency of the humidity
variation, which is linear as shown in Fig. 7, may be expressed
by mathematical formulas. For example, when a ratio of
■ breakthrough time (hereinafter referred to as, humidity
influence coefficient or humidity variation ratio in the case
of RH ^ 50%) is obtained based on the breakthrough time at which
the relative humidity RH is 50% as a reference, the humidity
influence coefficient may be expressed by a formula 5.
humidity influence coefficient in case where RH is ^ 50%
=exRH+f formula 5

e, f : constants experimentally obtained with the relative
humidity RH at least on two levels (however, which include one
level of a case where the relative humidity RH is equal to or
higher than 50%)
The formula 5 can be referred to as a humidity correction
formula that is required to calculate the breakthrough time of
the filtering portion 3.
{0076}
Also, as is evident in the Table 4 and Fig. 7, when the
relative humidity RH was less than 50%, the breakthrough time
was hardly changed, even if the relative humidity RH was changed.
The breakthrough time was nearly equal to a breakthrough time
in the case where the relative humidity RH was 50%. This
tendency (hereinafter referred to as a humidity influence
coefficient or a humidity variation ratio in the case of RH ^
50%) may be expressed by a formula 6.
humidity influence coefficient in case where RH is ^ 50%
= 1 • • • • • formula 6
{0077}
Finding 5. When the temperature T and the relative humidity
RH were constant, and the concentration Co and the flow rate
Q were changed, the relation of 1% breakthrough time depending
on the concentration and the flow rate that are the predictive

values of the breakthrough time before reaching breakthrough
concentration 1% (abbreviation: 1% breakthrough time
(concentration, flow rate) ) to 1% BTC of the formula 2 and 1%
BTQ of the formula 3 was shown by a formula 7.
1% breakthrough time (concentration, flow rate) = (1% BTC
/ reference BT) x (1% BTQ / reference BT) * reference BT = 1%
BTC x 1% BTQ x l / reference BT formula 7
Reference BT : breakthrough time regarding the reference
conditions of Finding 1. For example, 1% breakthrough time
(concentration) (1% BTC) is meant that is obtained by assigning
to the formulas 2 and 3 the concentration Co, the flow rate Q,
the temperature T, and the relative humidity RH, which are
common to the formulas 2 and 3. A value of 1% BTC in this time
is equal to a value of 1% breakthrough time (flow rate) (1% BTQ) .
The embodiment of the reference condition is such that, Co =
300ppm, Q = 30L/min, T = 20°C, RH = 50%, 1% breakthrough
concentration. The embodiment of the reference BT is 1% BTC
(= 1% BTQ) obtained based on the reference condition.
{0078}
Finding 6. when the concentration Co, the flow rate Q, the
temperature T, and the relative humidity RH are changed.with
respect to the reference conditions of the Finding 1, a
predictive value (1% breakthrough time) of the breakthrough

time before reaching 1% breakthrough concentration on the
downstream side of the filtering portion 3 is shown by the
relation expressed by formulas 8-1 and 8-2.
1% breakthrough time = reference breakthrough time x
concentration variation ratio * flow rate variation ratio *
temperature variation ratio x humidity variation ratio • • •
• • formula 8-1
1% breakthrough time = 1/ reference BT .* 1% BTC x 1% BTQ X
temperature variation ratio x humidity variation ratio • • •
• • formula 8-2
{0079}
Finding 7.
(1) About Breakthrough Concentration Having Arbitrary Value
and Concentration Co
a. The concentration of the poisonous gas (cyclohexane) on
the downstream side of the filtering portion 3 in the case of
the concentration Co = 300 ppm and the flow rate Q = 30 L/min
has increased with the lapse of observational time. Fig. 8
shows the way the concentration increased, and 1% breakthrough
time in Fig. 8 was 100.3 minutes.
b. The flow rate Q was fixed to 30 L/min, and the
concentration of the poisonous gas on the downstream side, which
is regarded as the breakthrough of the filtering portion 3, was

set to an arbitrary value (%) with respect to the concentration
Co on the upstream side of the filtering portion 3, for example,
to 0.5, 1, 3, 5, and 10 %, and the breakthrough time (%
breakthrough time) of the arbitrary value (%) was measured. As
for the concentration Co on the upstream side, its level was
changed from 100 to 1800 ppm, and on each level, a ratio of %
breakthrough time to 1% breakthrough time out of % breakthrough
time (% breakthrough concentration influence ratio
(concentration) or concentration variation ratio) was obtained,
and its result is shown in Table 5.
c. Table 5 shows that % breakthrough time was not affected
by the concentration Co on the upstream side if % breakthrough
time was seen in the form of % breakthrough concentration
influence ratio (concentration).
(2 ) About Breakthrough Concentration Having Arbitrary Value
and Flow Rate Q
a. The concentration Co on the upstream side was kept
constant, and the flow rate Q through the filtering portion 3
was changed, and the concentration of the poisonous gas on the
downstream side, which is regarded as the breakthrough of the
filtering portion 3, was set to an arbitrary value (%) with
respect to the concentration Co, for example, to 0.5, 1, 3, 5,
and 10 %, and the breakthrough time (% breakthrough time) of

the arbitrary value (%) was measured. As one example, the
concentration Co was fixed to 100 ppm, and the level of the flow
rate Q was changed from 30 to 120 L/min, and on each level, a
ratio of % breakthrough time to 1% breakthrough time (1% BT)
out of % breakthrough time (% BT) (% breakthrough concentration
influence ratio (flow rate)) was obtained, and its result is
shown in Table 6.
b. Table 6 shows a relation between the level of the flow
rate Q and % breakthrough time of the case where the
concentration Co is 100 ppm. Regarding % breakthrough time that
is seen in the form of % breakthrough concentration influence
ratio (flow rate), it has been found that, when the level of
the flow rate Q is changed, % breakthrough concentration
influence ratio (flow rate) is also changed.
c. In Table 6, the relation between % breakthrough
concentration influence ratio (flow rate) for each %
breakthrough concentration and % logarithm regarding %
breakthrough concentration was illustrated in a straight line
as shown in Fig. 9, and the gradient of the straight line was
changed with respect to the flow rate Q as shown in Fig. 10.
d. Based on-Table 6 and Fig. 10, it has been found that the
flow rate Q, % breakthrough concentration, and the ratio of %
breakthrough time to 1% breakthrough time (% breakthrough

concentration influence ratio (flow rate) or breakthrough time
ratio of arbitrary breakthrough concentration S ppm) have a
relation as shown in a formula 9.
ratio of (S ppm breakthrough time) to (1% BT) = i x EXP j
x Q x Ln (S / Co x 100) +1) formula 9
i, j : a constant obtained in such a manner that the
concentration Co, the temperature T, and the relative humidity
RH are kept constant, and the flow rate Q is changed at least
on three levels, and on each level of the flow rate Q, a ratio
of (% breakthrough time) to (1% BT) is acquired (however, the
breakthrough concentration is not limited to 1%, and generally
speaking, when values of A and B are different from each other,
it can be said that the constants are obtained by acquiring a
ratio of B% breakthrough time to A% breakthrough time on each
level of the flow rate Q).
S : arbitrary breakthrough concentration of filtering
portion 3 (unit ppm)
S / Co x 100 : % breakthrough concentration
The formula 9 may be referred to as a breakthrough reference
correction formula, wherein i * EXP D * Q may be expressed by
j-inear approximation, power approximation, ana ciiS j^iKe, in
addition to exponential approximation.
{0080}


{0082}
Finding 8 . Finding 7 shows that, if 1% breakthrough time,
which is a predictive breakthrough time in the case where the
breakthrough concentration of the filtering portion 3 is 1% of
the upstream concentration Co, is determined, and the
breakthrough concentration of the filtering portion 3 is set
to an arbitrary value, the predictive breakthrough time with
respect to the arbitrary value can be obtained by a formula 10

below.
breakthrough time = reference breakthrough time *
concentration variation ratio * flow rate variation ratio *
temperature variation ratio * humidity variation ratio *
breakthrough concentration variation ratio formula
10
In the formula 10;
reference breakthrough time : a duration time during which
the concentration on the downstream side of the filtering
portion reaches A% that is a value that is less than 100% and
arbitrarily set as the breakthrough concentration with respect
to the concentration Co, in the case where the concentration
Co, the flow rate Q, the temperature T, and the relative humidity
RH are kept constant,
concentration variation ratio : a correction coefficient
with respect to concentration variation calculated by obtaining
the reference breakthrough times for the concentration Co at
least on two levels while the flow rate, the temperature, and
the humidity are kept constant,
flow rate variation ratio : a correction coefficient with
respect <_o now rdts variation calcu-LaueQ oy occaming LUC
reference breakthrough times for the flow rate Q at least on
two levels while the concentration, the temperature, and the

humidity are kept constant,
temperature variation ratio : a correction coefficient with
respect to temperature variation calculated by obtaining the
reference breakthrough times for the temperature T at least on
two levels while the concentration, the flow rate, and the
relative humidity are kept constant,
humidity variation ratio : a correction coefficient with
respect to humidity variation calculated by obtaining the
reference breakthrough times for at least two levels including
one level at which the level of the relative humidity RH is equal
to or higher than 50% while the concentration, the flow rate,
and the temperature are kept constant,
breakthrough concentration variation ratio : a correction
coefficient with respect to breakthrough concentration
variation calculated by obtaining A% breakthrough times
corresponding to breakthrough concentration A% obtained with
respect to the flow rate Q at least on three levels, and B%
breakthrough time corresponding to breakthrough concentration
B% that is different from the breakthrough concentration A% on
one level out of the three levels of flow rate Q while the
concentration, the temperature, and the humidity are kept
constant.
{0083}

Finding 9. The formulas 2 to 9 and the predictive value of
the breakthrough time of the breakthrough concentration whose
unit is ppm are expressed by the formulas 11-1 and 11-2 below,
when the concentration of the poisonous gas on the upstream side
of -the filtering portion 3 is provided as Co ppm, and the
breakthrough concentration of the filtering portion 3 is
provided as S ppm.
predictive breakthrough time during which the downstream
side concentration reaches S ppm in the case of RH ^ 50%
(abbreviation: S ppm BT):
S ppm BT = 1 / Reference BT * (Coa x 10b) * (c * 1 / Q + d)
x (i xEXP j x Q x Ln (S / Co x 100) +1) x (e x RH + f) x (g x
T + h) formula 11-1
predictive breakthrough time during which the downstream
side concentration reaches S ppm in the case of RH < 50%
(abbreviation: S ppm BT) :
S ppm BT = 1 / reference BT x (Coa x iob) x (c x 1 / Q + d)
x (i x EXP j x Q x Ln (S / Co x 100) + 1) * (g x T + h) • • • •
• formula 11-2
{0084}
j, xuuxu^i x u . iiic txnuxilyo x uO zi ajLt; dX&u djJJJUUcUJUd LU
organic poisonous gases other than the cyclohexane. As is the
same case with the cyclohexane, regarding the poisonous gases

other than the cyclohexane, a breakthrough prediction formula
may be calculated for each poisonous gas through the application
of the Findings 1 to 9. However, where a poisonous gas whose
relative breakthrough ratio with respect to the cyclohexane is
known, the breakthrough time can be calculated by assigning a
value multiplied by the relative breakthrough ratio to the
breakthrough time concerning the cyclohexane. Also, as is the
same case with the cyclohexane, when the breakthrough-time
prediction formula for a specific poisonous gas other than the
cyclohexane is calculated, a gas whose relative breakthrough
ratio with respect to the breakthrough time concerning the
specific poisonous gas is evident, the breakthrough time of the
gas can be calculated by assigning a value multiplied by the
relative breakthrough ratio to the breakthrough time concerning
the specific poisonous gas to the breakthrough prediction
formula.
{0085}
The formulas 11-1 and 11-2 are programmed in the arithmetic
processing unit 25 of Fig. 1 and programmed in such a manner
that the formula 11-1 is selected in the case of RH ^ 50% and
the formula 11-2 is selected in the case of RH < 50%. Instead
of being programmed in this way, only the formula 11-1 may be
programmed in the arithmetic processing unit 25. In this case,

the arithmetic processing unit 25 is programmed in such a manner
that the formula 11-1 is selected in the case of RH ^ 50%, and
RH = 50% is selected in the formula 11-1 in the case of RH <
50%.
{0086}
As for the mask 1 of Fig. 1 under the conditions where the
formulas 2, 3, 4, 5, 6, 7, 8-2, 9, 11-1, and 11-2 have been
programmed in the arithmetic processing unit 25, the canister
KGC-1S (filtering element having 78 mm in diameter and 11.5 mm
in thickness) manufactured by Koken Ltd. was used for the
filtering portion 3 of the mask 1, and the cyclohexane was used
as the poisonous gas, and the concentration Co of the poisonous
gas, the flow rate Q of the air 40, the temperature T of the
air 40, the relative humidity RH of the air 40 were changed so
as to observe the breakthrough time of the filtering portion
3, and their results are shown in (1) to (9) below.
{0087}
(1) The air 40 having the temperature T = 20°C and the
relative humidity RH = 50% was passed through the filtering
portion 3 at a rate of the flow rate Q = 30 L/min. The
concentration Co of the poisonous gas in the air 40 is changed
on six levels such as 100 ppm, 300 ppm, 600 ppm, 1000 ppm, 1200
ppm, and 1800 ppm. The 1% breakthrough time (concentration)

(1% BTC) , which is a duration time during which the poisonous
gas leaked out to the downstream side of the filtering portion
3 reaches 1% of the concentration Co, was input to the arithmetic
processing unit 25 and, with respect to the formula 2 programmed
in the arithmetic processing unit 25, the following formula 12
was obtained.
1% BTc = Co-0-7863 x io3-9554 formula 12
{0088}
(2) The air 40 having the temperature T = 20°C and the
relative humidity RH = 50% and containing the poisonous gas
having the concentration Co = 300 ppm was passed through the
filtering portion 3 at the flow rate Q on six levels such as
30 L/min, 40 L/min, 60 L/min, 80 L/min, 100 L/min, 120 L/min,
and 1% BTQ on each level was input to the arithmetic processing
unit 25 and, with respect to the formula 3 programmed in,the
arithmetic processing unit 25, the following formula 13 was
obtained.
1% BTQ = 3696 x 1 / Q - 21.404 formula 13
{0089}
(3) In the formulas 12 and 13 that were provided as T = 20 °C,
RH = 50%, Co = 300 ppm, Q = 30 L/min, 1% BTC and 1% BTQ which
were obtained by the arithmetic processing unit 25, are 98.8
minutes. When 1% BTC (which is equal to 1% BTQ) under this

condition was regarded as a reference BT, the breakthrough time
in the case where the concentration Co and the flow rate Q were
changed at T = 20 °C and RH = 50% could be calculated by the formula
7 described before.
1% breakthrough time (concentration, flow rate) = 1% BTC x
1% BTQ x 1 / Reference BT formula 7
{0090}
(4) In the formula 7 programmed in the arithmetic processing
unit 25, the conditions of T = 20°C, RH = 50%, Co = 600 ppm,
and Q = 40 L/min were input to obtain a predictive breakthrough
time on calculation, which resulted in 41. 8 minutes. On the
other hand, when the air 40 was passed through the filtering
portion 3 of the mask 1 in Fig. 1 under the conditions of T =
20°C, RH = 50%, Co = 600 ppm, and Q = 40 L/min, and 1% breakthrough
time, which was a duration time during which the concentration
of the poisonous gas on the downstream side of the filtering
portion 3 reaches 1% of the concentration Co on the upstream
side, that is, 6 ppm, was measured, the 1% breakthrough time
was 38.9 minutes, which approximately corresponded with a
predictive breakthrough time that is 1% breakthrough time
vconceni_rat-ion, u-ow raney on cs±cui3Lion.
{0091}
(5) Regarding the mask 1 under the condition of RH = 50%,

Co = 300 ppm, and Q = 30 L/min, 1% BT was measured on five levels
of the temperatures T such as T = 15°C, 20°C, 25°C, 30°C, and
35°C, and the measurement results were input to the arithmetic
processing unit 25, and a formula 14 below was obtained with
respect to the formula 4 programmed in the arithmetic processing
unit 25.
temperature influence coefficient = - 0.0209 x T + 1.4199
formula 14
{0092}
(6) Regarding the mask 1 under the condition of T = 20°C,
Co = 300 ppm, and Q = 30 L/min, 1% BT was measured on eight levels
of the relative humidity RH such as RH = 10%, 20%, 30%, 40%,
50%, 60%, 70%, and 80%, and the measurement results were input
to the arithmetic processing unit 25, and a formula 15 was
obtained with respect to the formula 5 programmed in the
arithmetic processing unit 25 in the case of RH ^ 50%. Also,
in the case of R < 50%, the relative humidity influence
coefficient was applied to the formula 6 described before.
humidity influence coefficient in case of RH ^ 50%, = - 0. 0124
x RH + 1.6223 formula 15
humidity influence coefficient in case of RH < 50% = 1 •
• • • • formula 6
{0093}

(7) The condition of T = 35°C, RH = 70%, Co = 300 ppm, and
Q = 30 L/min was input to the arithmetic processing unit 25,
and 1% predictive breakthrough time calculated based on the
formulas 8-2, 14, and 15 programmed in the arithmetic processing
unit 25 was 50. 8 minutes. On the other hand, when the air 40
is passed through the filtering portion 3 of the mask 1 under
the condition of T = 35°C, RH = 70%, Co = 300 ppm, and Q = 30
L/min, the breakthrough time with respect to 1% of breakthrough
concentration actually measured is 49.9 minutes, which
approximately corresponds with a predictive breakthrough time
on calculation.
{0094}
(8) When the air 40 of. T = 20°C, RH = 50%, Co = 300 ppm,
and Q = 30 L/min was passed through the filtering portion 3 of
the mask 1, a duration time was measured during which the
concentration of the poisonous gas leaked out to the downstream
side of the filtering portion 3 reached 0.5% (hereinafter
referred to as 0.5% breakthrough time), reached 1% (1%
breakthrough time) , reached 3% (3% breakthrough time) , reached
5% (5% breakthrough time), and reached 10% (10% breakthrough
time) witii respect to Co = 3uu ppm, wnich was tue concentration
on the upstream side of the filtering portion 3, and the
measurement results were input to the arithmetic processing

unit 25, and formulas 16 and 17 below were obtained with regard
to the formulas 11-1 and 11-2 programmed in the arithmetic
processing unit 25.
{0095}
With regard to the formula 11-1 in the case of RH ^ 50%
S ppm BT = 1 / reference BT x (Co"0-7863 x 103-9554) x (3696 *
1 / Q - 21.404) x (0.1264 x EXpo.oi93 * Q X Ln (S / Co X 100) +
1) x (-0.0124 x RH + 1.6223) x (-0.0209 x T + 1.4199) ....
• formula 16
It should be noted that, for example, when the concentration
on the downstream side is 5 ppm, S = 5 is assigned.
{0096}
With regard to the formula 11-2 in the case of RH < 50%
S ppm BT = 1 / reference BT x (Co"0"7863 x i03-9554) x (3696 x
1 / Q - 21.404) x (0.1264 x EXp0-0193 x Q x Ln (S / Co x 100) +
1) x (-0.0209 x T + 1.4199) formula 17
It should be noted that, for example, when the concentration
on the downstream side is 5 ppm, S = 5 is assigned.
{0097}
(9) While the predictive breakthrough time (5 ppm BT) in
the case of S = 5 in the formula 16 is calculated on various
conditions, the breakthrough time of the mask 1 has been
actually measured on each condition. As shown in Table 7, the

predictive breakthrough time (S ppm BT) approximately
corresponds with the actual measured breakthrough time on each
condition, which proves a remarkable accuracy of the predictive
breakthrough time according to the formula 16.
{0098}
As is evident in this example, in the mask 1 using the
canister KGS-1S or other filtering portion 3 which is equivalent
to that of KGS-1S, the formulas 16 and 17 are programmed in the
arithmetic processing unit 25, so that, when the temperature
T, the relative humidity RH, the concentration Co, and the flow
rate Q in the environment where the mask 1 is used are input,
the breakthrough time in the environment can be calculated.
Regarding the mask 1, one example in which the formulas 16 and
17 are input in the arithmetic processing unit 25 includes the
input of reference conditions that are inherent in
manufacturing the filtering portion 3. When the filtering
portion 3 starts being used, the temperature T and the relative
humidity RH of the air 40 in the use environment are detected,
and filtering capacity determined by the reference conditions
of the filtering portion 3 based on the formulas 4 and 5 can
be corrected in such a manner as to correspond to the use
environment.
{0099}

Also, in the mask 1 that uses the filtering portion 3 whose
specifications are different from those of the canister KGS-1S,
data obtained based on the use of the filtering portion 3 are
input to the formulas 11-1 and 11-2 programmed in the arithmetic
processing unit 25, and constants regarding the formulas 11-1
and 11-2 are calculated, the breakthrough time of the filtering
portion 3 corresponding to the environment where the mask 1 is
used may be calculated.
{0100}

{0101}
The results in Table 7 show research results in the condition
where the temperature T, the relative humidity RH, the
concentration Co, and the flow rate Q of the air 40, which is
outside air, are considered to be invariable in a period from
the start of measuring the breakthrough time regarding the mask
1 in which the canister KGC-1S is used for the filtering portion
3 to the breakthrough of the mask 1. By "the flow rate Q is

invariable" is meant that the flow of the air 40 is a steady
flow or a flow that is not exactly the steady flow but is
considered to be the steady flow.
{0102}
Apart from this condition, the mask 1 is often used in the
condition where at least one of the temperature T, the relative
humidity RH, the concentration Co, and the flow rate Q is changed
with a lapse of time. The example in which the flow rate Q in
the mask 1 is changed from one minute to the next along with
the repeat of the inhalation and exhalation of the wearer is
a typical example concerning the condition.
{0103}
Fig. 11 is a graph illustrating one example of a pulsating
flow in which the flow rate of air through the filtering portion
3 with regard to the inhalation and exhalation at the time the
wearer breathes is changed along with a lapse of time. In Fig.
11, it is assumed that the inhalation operation to inhale the
air 40 is repeated at the rate of 20 times a minute while the
flow rate of one breath of air, that is, the amount of inhalation
is 1.5 L. It is assumed that it takes three seconds to carry
out the one—time inhalation and exhalation operations, and the
flow rate of air changed in the one-time inhalation and
exhalation operations depicts a sinusoidal wave. In these

inhalation and exhalation operations, the flow rate measuring
unit 22 in Fig. 2 detects the flow rate of the air as a target
to be detected in the inhalation operation. The flow rate of
the air in the exhalation operation does not pass through the
filtering portion 3. Accordingly, the flow rate of the air is
treated as zero in the flow rate measuring unit 22. A dot-dash
line DL in Fig. 11 shows the variation in the flow rate of the
air to be detected in the flow rate measuring unit 22. In order
to predict the breakthrough time of the mask 1 under the
condition where the flow rate Q of the filtering portion 3 is
changed as shown in the dot-dash line DL, it is preferable that
the flow rate Q per unit time t be measured so as to get a degree
of breakthrough progress per unit time with regard to the mask
1 along with a lapse of time. The unit time t can be set to
an arbitrary time, and it is preferable that the unit time t
be in a range of 1/6000 min (0.01 second) to 5/600 min (0.5
second) to calculate the degree of breakthrough progress
corresponding to the ever-changing variation of the flow rate
Q of the breathing of the wearer. A broken line G of Fig. 11
shows the variation of the flow rate on the assumption that the
unit time t is 1/600 min (0.1 second), and during 0.1.second,
the flow rate is invariable as a steady flow. The concentration
Co, the flow rate Q, the temperature T, and the relative humidity

RH may be measured based on the same unit time as that of the
flow rate Q. However, unless the ever-changing variation
occurs as in the case of the flow rate Q, it may be such that
the concentration Co, the temperature T, and the relative
humidity RH are measured based on a unit time longer than the
unit time applied to the flow rate Q, for example, 10 min (600
seconds) or much longer. The degree of breakthrough progress
is defined by a formula 18 below in which S ppm BT of the formulas
16 and 17 programmed in the arithmetic processing unit 25 is
used.
degree of breakthrough progress = unit time t / S ppm BT
formula 18
{0104}
The f ormula 18 is a formula to calculate the breakthrough
time required to reach the breakthrough concentration S ppm in
the mask 1, that is, the degree of breakthrough progress per
unit time with respect to S ppm BT. For example, when the unit
time t is 1/600 min (0.1 second) , and S ppm is 5 ppm, the formula
.18 is expressed as follows.
degree of breakthrough progress = 1 / 600 / 5 ppm BT
rni nm
The formula 18 is programmed in the arithmetic processing
unit 25, Co = 300 ppm, the pulsating flow rate 30 L/min

(sinusoidal wave pulsating flow of 1.5 L * 20 times/min, which
is illustrated in Fig. 11) , T = 20°C, RH = 50%, the breakthrough
reference concentration of 5 ppm, and the unit time t = 1/600
min (0.1 second)were input to the arithmetic processing unit
25, and a time required for a value obtained by multiplying the
degree of breakthrough progress to reach 1 was calculated. As
the result of calculation, the predictive breakthrough time to
be obtained was 91.9 minutes. Also, as for the mask 1, when
the breakthrough time was actually measured under the
breakthrough concentration having 5 ppm, the result was 94.6
minutes, which approximately corresponds with the predictive
breakthrough time.
{0106}
In the arithmetic processing unit 25 in which the degree
of breakthrough progress is programmed, a use ratio or a
residual use ratio (residual life span) of the filtering portion
3 and the like at an arbitrary time after starting the use of
the mask 1 can be calculated according to formulas 19 to 21 below.
use ratio (%) of filtering portion 3 = degree of breakthrough
progress * 10 formula 19
residual use ratio (%) of filtering portion 3 = 100 - use
ratio (%) formula 20
residual time regarding filtering portion 3 = (use time of

filtering portion 3 / degree of breakthrough progress) - (use
time of filtering portion 3) formula 21
{0107}
The calculation results of the formulas 19 to 21 can be.
displayed on a display 27a through the arithmetic processing
unit 25. Also, the alarm 26a can be operated based on the
calculation results.
{0108}
Even if the environment conditions where the mask 1 is worn
are changed along with a lapse of time, the mask 1 in which the
environment conditions such as the concentration Co and the flow
rate Q are input per unit time so as to calculate the degree
of breakthrough progress may calculate the breakthrough time
corresponding to the change. Accordingly, in a state where the
filtering portion is used under the condition where the degree
of breakthrough progress exceeds 1, for example, in a case where
the breakthrough concentration is set to a threshold value of
the poisonous gas, a hazardous condition can be prevented where
the mask 1 continues to be worn without replacing the filtering
portion notwithstanding that the poisonous gas having the
concentration uigiier tuan tne tarssnoxQ vaxue is iiowmg out
to the downstream side of the filtering portion. Further, on
the assumption that the arithmetic processing unit 25 is set

in a manner as to activate the alarm, for example, at a time
when the degree of breakthrough progress reaches 0.9, the wearer
can move from a place where there exists the poisonous gas to
a place where there exists no poisonous gas in plenty of time.
That is, the occurrence of the condition can be prevented where
the canister reaches the breakthrough state while the wearer
moves, and the wearer is exposed to the poisonous gas having
the concentration higher than the threshold value.
{0109}
There is a case where the air 40 on the upstream side of
the filtering portion 3 in the mask 1 includes various types
of poisonous gases, for example, a mixed gas made up of
cyclohexane and toluene. In the mask 1 applied for the air 40
described above, firstly, the formulas 11-1 and 11-2 for the
prediction of the breakthrough time of the air 40 including only
the cyclohexane are produced in the arithmetic processing unit
25. Secondly, the formulas 11-1 and 11-2 for the prediction
of the breakthrough time of the outside air including only the
toluene are produced. Thirdly, the concentration per unit time
with regard to each poisonous gas is input to the formula of
the degree of breakthrough progress, which is calculated based
on the formulas 11-1 and 11-2 for the prediction of the
breakthrough time, and a time point when the sum of the

multiplication result of the degrees of breakthrough progress
of the cyclohexane and toluene reaches 1 is the breakthrough
time of the mixed gas in the mask 1.
{0110}
A formula 22 below is provided to predict the breakthrough
time based on a relative breakthrough ratio (RBT) in place of
the reference BT in the formula 16. When the relative
breakthrough ratio of the cyclohexane gas is 1, the relative
breakthrough ratios of the other poisonous gases _ are
exemplified by the Table 8. Incidentally, these relative
breakthrough ratios are known to the skills in the art.
BT (Sppm BT) = 0.00997 / RBT x ((3273 x RBT + 452) / Q -
((3273 x RBT + 452) / 30 - 100.3 x RBT)) x ( (Co-0"7863 x i03-9554)
x (1 + log (300) / log (Co) x (RBT -1))) x T)))-o.6i35) x Ln (s
/ Co x 100) + 1) x (- 0.0207 x (T - 20) x 1 / RBT1/2 + 1) x (-
0.0124 x (RH - 50) x 1 / RBT1/2 + 1) • • • • • formula 22
In the formula 22 above:
RBT : relative breakthrough ratio
1 / reference RBT = 0.00997 / relative breakthrough ratio
flow rate depending part : ((3273 x RBT + 452) / Q - ((3273
x RBT + 452) / 30 - 100.3 x RBT))
concentration depending part : ( (Co-0'7863 x ]_g3'9554) x (1 +
log (300) / log (Co) x (RBT - 1)))

breakthrough time ratio based on arbitrary breakthrough
reference : ((0.2222 x (0.00997 x ((3273 x RBT + 452) / Q - ( (3273
x RBT + 452) / 30 - 100.3 x RBT)))"0"6135) x Ln (S / Co 'x 100)
+ 1)
temperature depending part : (- 0.0207 x (T - 20) x i / RBT1/2
+ 1)
humidity depending part : (- 0.0124 x (RH - 50) x l / RBT1/2
+ 1)
{0111}
In Table 8, regarding 1% breakthrough time for various types
of poisonous gases (test gases) applied in the mask 1, in Fig.
1, in which the canister KGC-1S is mounted, values calculated
through the formula 22 and values actually measured are
respectively shown in the cases of the steady flow and the
pulsating flow. It should be noted that, when the flow rate
Q is 30 L/min, the pulsating flow is provided as a pulsating
flow of a sinusoidal wave of 1.5 L x 20 times/min, and when the
flow rate Q is 20 L/min, the pulsating flow is provided as a
pulsating flow of a sinusoidal wave of 1.0 L * 20 times/min.
Concerning the prediction of the pulsating flow, 1 / 600 min
(0.1 second) is used as the unit time t in the formula 18.
{0112}
A formula 23 below is the correction of the formula 22 in

such a manner as to calculate the breakthrough time in
consideration of a dissolution rate (Hy%) of an organic solvent
in water. Incidentally, the organic solvent is such that its
vapor is considered to be poisonous.
dissolution rate : degree of dissolution ,in water x 100 (%)
BT = 0.00997 / RBT x ((3273 x RBT + 452) / Q - ((3273 x RBT
+ 452) / 30. - 100.3 x RBT)) x ( (Co-0-7863 x 103"9554) x (1 + log
(300) / log (Co) x (RBT -1))) x 3' x RBT) ) ) _0"6135) x Ln (S / Co
x 100) + 1) x (- 0.0207 x (T - 20) x 1 / RBT1/2 + 1) x (- 0.0124
x (RH - 50) x (100 - Hy) / 100 x 1 / RBT1/2 +1) formula
23
{0113}
In Table 8, in MEK or cellosolve whose dissolution rate Hy
is equal to or higher than 20%, when the relative humidity RH
is 80%, the difference between the prediction value and the
actual measured value of % breakthrough time tends to increase.
In the formula 23, the humidity depending part of the formula
22, that is, (- 0.0124 x (RH - 50) x 1 / RBT1/2 + 1) is corrected
as (- 0.0124 x (RH - 50) x (100 - Hy) / 100 x 1 / RBT1/2 + 1),
so that the prediction value ("prediction value in
consideration of dissolution rate") can be brought close to the
measured value (see Table 8) . In the formula 23, the maximum
value of the dissolution rate Hy is set to 50 (%). When the

dissolution rate is equal to or higher than 50%, there is no
variation in influence on the breakthrough time. Accordingly,
even when the dissolution rate is equal to or higher than 100%,
the dissolution rate is provided as 50% in calculation.
{0114}
{Table 8}

{0115}
In the mask 1 of Fig.l, a formula 24 described below is a
formula for the breakthrough-time prediction formula, which is
obtained through the procedure similar to that of KGS-1S, with
regard to a canister KGC-1L manufactured by Koken Ltd. and
having a filtering element (having 78 mm in diameter and 22.5mm
in thickness) different from that of the canister KGC-1S
including the formula 16. That is, test conditions of the
temperature T, the relative humidity RH, the concentration Co,
and the flow rate Q in Table 1 were applied to the canister KGC-1L,
and the influence on the breakthrough time was observed in the
course of the variation in the concentration Co and the like.
The reference condition was such that the temperature T = 20 °C,
the relative humidity RH = 50%, the concentration Co = 300 ppm,
the flow rate Q = 300 L/min, and 1% breakthrough time
(concentration) were applied. On the basis of the reference
condition, 1% predictive breakthrough time by the formula 24
in which the temperature T = 20°C, the relative humidity RH =
50%, the concentration Co = 600 ppm, the flow rate Q = 80 L/min
were provided was 58.2 minutes, and the actual measured value
of 1% breakthrough time was 61.9 minutes. Under the same test
condition, the predictive breakthrough time of 5 ppm was 56.7
minutes, and the actual measured value of breakthrough time of

5 ppm was 60.1 minutes. Also, 1% predictive breakthrough time
in the case where the concentration Co was 1800 ppm, and the
flow rate Q was 80 L/min is 22.8 minutes, and the actual measured
value of 1% breakthrough time was 23.2 minutes. Under the same
condition, the predictive breakthrough time of 5 ppm was 18.7
minutes, and the actual measured value of breakthrough time of
5 ppm was 18 . 2 minutes . Thus, in the case of the canister KGC-1L,
the prediction value and the actual measured value of the
breakthrough time were approximately matched.
BT = 0.00306 x (Co'0"8541 x 104"6328) x (10300 x (1 / Q) - 24.233)
x ((0.0724 x EXP (°-0082>) xLn (S / Co x 100) + 1)
It should be noted that the temperature T is fixed to 20°C,
and the relative humidity RH is fixed to 50%.
r r\ i i c i
\ u J_ x \J /
Fig. 12 is a side cross-sectional view of a local exhaust
device 50 according to an embodiment of the present invention.

The local exhaust device 50 is also referred to as the air
cleaning apparatus, and a work booth 55 is formed on the upstream
side of the device 50. A first duct 51 is extended from the
booth 55 toward the downstream side. A downstream-side end
portion of the first duct 51 is connected to the filtering
portion 3 including the filtering element 3a. A second duct
52 is extended from the filtering portion 3 toward the
downstream side. A downstream-side end portion of the second
duct 52 is connected to an exhaust chamber 56. The exhaust
chamber 56 includes an exhaust fan 57, which allows air 60 in
the inside of the booth 55 to transfer from the upstream side
to the downstream side and discharge the air 60 to the outside
of the exhaust chamber 56 as purified air 61. In the inside
of the first duct 51, the sensors 21a, 22a, 23a, and 24a are
respectively provided for the concentration measuring unit 21,
the flow rate measuring unit 22, the temperature measuring unit
23, and the humidity measuring unit 24. The measuring units
21, 22, 23, and 24 are electrically connected to the arithmetic
processing unit 25. The arithmetic processing unit 25 includes
a display means such as the alarm 26a and the display 27a. In
Fig. 12, it is possible to connect the arithmetic processing
unit 25 to the respective measuring units 21, 22, 23, and 24
by radio. It is also possible to connect the arithmetic

processing unit 25 to the alarm 26a and the display 27a by radio.
{0117}
In the device 50, the poisonous gas is generated in the booth
55. The air 60 including the poisonous gas corresponds to the
air 40 in Fig. 1 and is purified through the filtering'portion
3 and discharged as the purified air 61.
{0118}
In the device 50, the flow rate of the air 60 is substantially
the same on the upstream side and the downstream side of the
filtering portion 3, and the sensor 22a to measure the flow rate
is provided on the upstream side of the filtering portion 3.
However, as is the same case with the example in Fig. 2, it is
possible to provide the sensor 22a on the downstream side of
the filtering portion 3.
{0119}
Fig. 13 is a diagram illustrating the gas mask 1 according
to an embodiment of the present invention. The mask 1 includes
an air supply unit 71 to supply inhalation air to the facepiece
2 via an air supply tube 70. A flow meter 72 and an adsorbent
unit 73 are provided between the facepiece 2 and the air supply
,inif 11 -M^,~J -,-!--! , ^K^^-l 4-^, -> U,-.r^^-^_'k^-,^l -^^,-C-^l TC 7\ 1 -S-"U „,, „!-, v->, ~-v-
Ull-i- u i J- ailu auLQ^ucu uw a. nuiuaii "iicau xuu»uci /o. 2-iJ_uii^ui_jll fiou
shown, the gas mask 1 includes a concentration measuring unit,
a temperature measuring unit, a humidity measuring unit, and

an arithmetic processing unit as seen in Fig. 1. Since the
supply amount of inhalation air from the air supply unit 71 is
invariably constant, the flow meter 72 may be provided on the
upstream side of the adsorbent unit 73 as shown in the diagram
and may be provided on the downstream side.
{Reference Signs List}
{0120}
1 air cleaning apparatus (mask)
3 filtering portion
3a filtering element
21 concentration measuring unit
21a detector- (sensor)
22 flow rate measuring unit
22a detector (sensor)
23 temperature measuring unit
23a detector (sensor)
24 humidity measuring unit
24a detector (sensor)
25 arithmetic processing unit
26a alarm
27 display
40 outside air
50 local exhaust device

60 air
71 air supply unit
72 flow rate measuring unit (flow meter)
Co concentration
Q flow rate
T temperature
RH relative humidity

{Claims}
{Claim 1}
An air cleaning apparatus comprising a filtering portion
to allow air contaminated with a poisonous gas to pass through
from an upstream side to a downstream side so as to remove the
poisonous gas, and configured to be capable of predicting a
breakthrough time until concentration of the poisonous gas on
the downstream side of the filtering portion reaches
breakthrough concentration, which is arbitrarily set- with
respect to the concentration of the poisonous gas,
wherein the air cleaning apparatus further comprises an
arithmetic processing unit configured to input data on the
concentration of the poisonous gas included in the air on the
upstream side of the filtering portion, a flow rate of the air
passing through the filtering portion, a temperature of the air
on the upstream side, and relative humidity of the air on the
upstream side, and
wherein a breakthrough-time prediction formula in which the
concentration of the poisonous gas included in the air on the
upstream side of the filtering portion used in the air cleaning
apparatus, the flow rate, the temperature, and the relative
humidity are provided as variables is programmed in the

arithmetic processing unit, and the breakthrough time is
predictable by the prediction formula based on the data.
{Claim 2}
The air cleaning apparatus according to claim 1,
wherein the prediction formula is formulated in the
arithmetic processing unit prior to use of the air cleaning
apparatus, based on a reference condition that is constituted
by the concentration of the poisonous gas included in the air
on the upstream side, the flow rate, the temperature, the
relative humidity, and the breakthrough concentration, and on
the breakthrough time measured under the reference condition.
{Claim 3}
The air cleaning apparatus according to claim 2,
wherein the arithmetic processing unit corrects the
breakthrough time of the reference condition for the filtering
portion, based on the temperature and the relative humidity.
{Claim 4}
The air cleaning apparatus according to any one of claims
1 to 3, further comprising at least one of a detector of the
concentration of the poisonous gas, a detector of the flow rate,
a detector of the temperature, and a detector of the relative
humidity.
{Claim 5}

The air cleaning apparatus according to claim 4,
wherein the detector for any item of the data, out of the
data on the concentration of the poisonous gas in the air on
the upstream side of the filtering portion, the blow rate, the
temperature, and relative humidity, is not used when the item
has a constant value during use of the air cleaning apparatus.
{Claim 6}
The air cleaning apparatus according to any one of claims
1 to 5,
wherein the arithmetic processing unit is used in a cordless
state.
{Claim 7}
The air cleaning apparatus according to any one of claims
1 to 6,
wherein at least one item of the data, out of the data on
the concentration of the poisonous gas included in the air on
the upstream side of the filtering portion, the flow rate, the
temperature, and the relative humidity, is input to the
arithmetic processing unit by radio.
{Claim 8}
The air cleaning apparatus according to any one of claims
1 to 7,

wherein the poisonous gas is a reference gas provided as
a toxic gas to be arbitrarily selected, and concentration of
the reference gas on the upstream side is represented as Co (ppm) ,
and the flow rate is represented as Q (L/min) , and the
breakthrough concentration is represented as S (ppm) , and a time
during which concentration of the reference gas on the
downstream side reaches S (ppm) is the breakthrough time, and
wherein the prediction formula is represented by a formula
below,
breakthrough time = reference breakthrough time ×
concentration variation ratio × flow rate variation ratio ×
temperature variation ratio × humidity variation ratio ×
breakthrough concentration variation ratio;
reference breakthrough time: a duration time during which
the concentration on the downstream side of the filtering
portion reaches A%, which is a value that is less than 100% and
arbitrarily set as the breakthrough concentration with respect
to the concentration Co, in a case where the concentration Co,
the flow rate Q, the temperature T, and the relative humidity
RH are kept constant;
concentration variation ratio: a correction coefficient
with respect to concentration variation calculated by obtaining
the reference breakthrough times for the concentration Co at

least on two levels while the flow rate, the temperature, and
the humidity are kept constant;
flow rate variation ratio: a correction coefficient with
respect to flow rate variation calculated by obtaining the
reference breakthrough times for the flow rate Q at least on
two levels while the concentration, the temperature, and the
humidity are kept constant;
temperature variation ratio: a correction coefficient with
respect to temperature variation calculated by obtaining the
reference breakthrough times for the temperature T at least on
two levels while the concentration, the flow rate, and the
relative humidity are kept constant;
humidity variation ratio: a correction, coefficient with
respect to humidity variation calculated by obtaining the
reference breakthrough times for at least two levels including
one level at which a level of the relative humidity RH is equal
to or higher than 50% while the concentration, the flow rate,
and the temperature are kept constant;
breakthrough concentration variation ratio: a correction
coefficient with respect to breakthrough concentration
variation calculated by obtaining an A% breakthrough time
corresponding to the breakthrough concentration A% obtained
with respect to the flow rates Q at least on three levels, and

a B% breakthrough time corresponding to breakthrough
concentration B% that is different from the breakthrough
concentration A% on one level of flow rate Q while the
concentration, the temperature, and the humidity are kept
constant.
{Claim 9}
The air cleaning apparatus according to claim 8,
wherein the formula of claim 8 is represented by formulas
(1) and (2) described below,
(1) in a case of the relative humidity RH ≥ 50%,
breakthrough time = 1 / reference breakthrough time × (Coa
× 10b) × (c × 1 / Q + d) × (i × EXP j × Q × Ln (S / Co × 100) +
1) × (e × RH + f) × (g x T + h) ;
(2) in a case of the relative humidity RH < 50%,
breakthrough time = 1 / reference breakthrough time ×
(Coa × 10b) × (c × 1 / Q + d) × (i x EXP j × Q × Ln (S / Co × 100)
+1) × (g × T + h); and
in the formulas (1) and (2) above,
reference breakthrough time: a duration time during which
the concentration on the downstream side reaches A%, which is
a value that is less than 100% and arbitraily set with respect
to the concentration Co, in a case where the concentration Co,

the flow rate Q, the temperature T, and the relative humidity
RH are kept constant;
T: temperature (°C);
RH: relative humidity (%);
a, b: constants obtained based on the concentration Co at
least on two levels and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration Co with
regard to each concentration Co while the flow rate Q, the
temperature T, and the relative humidity RH are kept constant;
c, d: constants obtained based on the flow rates Q at least
on two levels and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration Co with
regard to each flow rate Q while the concentration Co, the
temperature T, and the relative humidity RH are kept constant;
e, f: constants obtained based on at least two levels
including one level at which a level of the relative humidity
RH is equal to or higher than 50%, and a breakthrough time during
which the concentration of the poisonous gas on the downstream
side of the filtering portion reaches A% of the concentration
Co with regard to each relative humidity RH while the

concentration Co, the flow rate Q, and the temperature T are
kept constant;
g, h: constants obtained based on temperatures at least on
two levels, and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration Co with
regard to each temperature T while the concentration Co, the
flow rate Q, and the relative humidity RH are kept constant;
i, j : constants obtained based on the A% breakthrough times
and the flow rates Q in a case where the flow rate Q is changed
at least on three levels, and the B% breakthrough time using
one level out of the three levels of flow rate Q at which the
A% breakthrough time is obtained, while the concentration Co,
the temperature T, and the relative humidity RH are kept
constant.
{Claim 10}
The air cleaning apparatus according to any one of claims
1 to 9,
wherein the arithmetic processing unit is programmed in such
a manner that the breakthrough time is calculated by using a
of the poisonous gas.
{Claim 11}

The air cleaning apparatus according to claim 10,
wherein correction based on a dissolution rate in water in
a case where the poisonous gas is in a liquid state is made for
prediction of the breakthrough time for which the relative
breakthrough ratio is used.
{Claim 12}
The air cleaning apparatus according to any one of claims
1 to 11,
wherein, in the arithmetic processing unit, a degree of
breakthrough progress per unit time with respect to the
filtering portion can be obtained, and the breakthrough time
of the filtering portion is calculated by multiplying the degree
of breakthrough progress.
{Claim 13}
The air cleaning apparatus according to claim 12,
wherein a time ranging from 1/6000 to 5/600 min is used for
the unit time.
{Claim 14}
The air cleaning apparatus according to any one of claims
1 to 13,
wherein the arithmetic processing unit can calculate at
least one of a residual breakthrough time and a residual use
ratio with respect to the filtering portion.

{Claim 15}
The air cleaning apparatus according to any one of claims
1 to 14,
wherein the air cleaning apparatus is made up of any of a
gas mask and a local exhaust device.
{Claim 16}
The air cleaning apparatus according to claim 15,
wherein the detector of the flow rate is arranged in any
of the upstream side and the downstream side of the filtering
portion in the gas mask.
{Claim 17}
The air cleaning apparatus according to claim 15,
wherein the detector of the flow rate is arranged in any
of the upstream side and the downstream side of the filtering
portion in the local exhaust device.
{Claim 18}
A method, in a case where air contaminated with a poisonous
gas passes through a filtering portion of an air cleaning
apparatus from an upstream side to a downstream side, for
predicting a breakthrough time until concentration of the
poisonous gas on the downstream side Of the filtering portion
reaches breakthrough concentration, which is arbitrarily set
with respect to the concentration of the poisonous gas,

wherein, in the air cleaning apparatus, data on the
concentration of the poisonous gas included in the air on the
upstream side of the filtering portion, a flow rate of the air
passing through the filtering portion, a temperature of the air
on the upstream side, and relative humidity of the air on the
upstream side, are input to an arithmetic processing unit, and
wherein, in the arithmetic processing unit, the
breakthrough time is calculated based on the data and a
breakthrough-time prediction formula programmed in the
arithmetic processing unit, where the concentration of the
poisonous gas included in the air on the upstream side, the flow
rate, the temperature, and the relative humidity are provided
as variables.
{Claim 19}
The method according to claim 18,
wherein the breakthrough-time prediction formula is
formulated in the arithmetic processing unit prior to use of
the air cleaning apparatus, based on a reference condition that
is constituted by the concentration of the poisonous gas
included in the air on the upstream side, the flow rate, the
temperature, the relative humidity and the breakthrough
concentration, and on the breakthrough time measured under the
reference condition.

{Claim 20}
The method according to claim 19,
wherein the arithmetic processing unit corrects the
breakthrough time of the reference condition for the filtering
portion, based on the temperature and the relative humidity.
{Claim 21}
The method according to any one of claims 18 to 20,
wherein the poisonous gas is a reference gas provided as
a toxic gas to be arbitrarily selected, and concentration of
the reference gas on the upstream side is represented as Co (ppm),
and the flow rate is represented as Q (L/min) , and the
breakthrough concentration is represented as S (ppm) , and a time
during which concentration of the reference gas. on the
downstream side reaches S (ppm) is the breakthrough time, and
wherein the prediction formula is represented by a formula
below,
breakthrough time = reference breakthrough time ×
concentration variation ratio × flow rate variation ratio ×
temperature variation ratio × humidity variation ratio ×
breakthrough concentration variation ratio;
reference breakthrough time:a duration time during which
the concentration on the downstream side of the filtering
portion reaches A%, which is a value that is less than 100% and

arbitrarily set as the breakthrough concentration with respect
to the concentration Co, in a case where the concentration Co,
the flow rate Q, the temperature T, and the relative humidity
RH are kept constant;
concentration variation ratio: a correction coefficient
with respect to concentration variation calculated by obtaining
the reference breakthrough times for the concentration Co at
least on two levels while the flow rate, the temperature, and
the humidity are kept constant;
flow rate variation ratio: a correction coefficient with
respect to flow rate variation calculated by obtaining the
reference breakthrough times for the flow rates Q at least on
two levels while the concentration, the temperature, and the
humidity are kept constant;
temperature variation ratio: a correction coefficient with
respect to temperature variation calculated by obtaining the
reference breakthrough times for the temperatures T at least
on equal to or more than two levels while the concentration,
the flow rate, and the relative humidity are kept constant;
humidity variation ratio: a correction coefficient with
respect to humidity variation calculated by obtaining the
reference breakthrough times for at least two levels including
one level at which a level of the relative humidity RH is equal

to or higher than 50% while the concentration, the flow rate,
and the temperature are kept constant;
breakthrough concentration variation ratio: a correction
coefficient with respect to breakthrough concentration
variation calculated by obtaining an A% breakthrough time
corresponding to the breakthrough concentration A% obtained
with respect to the flow rates Q at least on three levels, and
a B% breakthrough time corresponding to breakthrough
concentration B% that is different from the breakthrough
concentration A% on one level of flow rate Q while the
concentration, the temperature, and the humidity are kept
constant.
{Claim 22}
The method according to claim 21,
wherein the formula of claim 21 is represented by formulas
(1) and (2) described below,
(1). in a case of the relative humidity RH ≥ 50%,
breakthrough time = 1 / reference breakthrough time × (Coa
× 10b) × (c × 1 / Q + d) × (i × EXP j × Q × Ln (S / Co × 100) +
1) × (e × RH + f) × (g × T + h) ;
(2) in a case of the relative humidity RH < 50%,

breakthrough time = 1 / reference breakthrough time × (Coa
× 10b) × (c × 1 / Q + d) × (i × EXP j × Q × Ln (S / Co × 100) +
1) × (g × T + h); and
in the formulas (1) and (2) above,
reference breakthrough time: a duration time during which
the concentration on the downstream side reaches A%, which is
a value that is less than 100% and arbitrarily set with respect
to the concentration Co, in a case where the concentration Co,
the flow rate Q, the temperature T, and the relative humidity
RH are kept constant;
T: temperature (°C);
RH: relative humidity (%);
"a, b: constants obtained based on the concentration Co at
least on two levels and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration Co with
regard to each concentration Co while the flow rate Q, the
temperature T, and the relative humidity RH are kept constant;
c, d: constants obtained based on the flow rates Q at least
on two levels and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration Co with

regard to each flow rate Q while the concentration Co, the
temperature T, and the relative humidity RH are kept constant;
e, f: constants obtained based on at least two levels
including one level at which a level of the relative humidity
RH is equal to or higher than 50%, and a breakthrough time during
which the concentration of the poisonous gas on the downstream
side of the filtering portion reaches A% of the concentration
Co with regard to each relative humidity RH while the
concentration Co, the flow rate Q, and the temperature T are
kept constant;
g, h: constants obtained based on temperatures at least on
two levels, and a breakthrough time during which the
concentration of the poisonous gas on the downstream side of
the filtering portion reaches A% of the concentration Co with
regard to each temperature T while the concentration Co, the
flow rate Q, and the relative humidity RH are kept constant;
i, j : constants obtained based on an A% breakthrough time
and the flow rate Q in a case where the flow rate Q is changed
at least on three levels, and a B% breakthrough time on one level
out of the three levels of the flow rate Q at which the A%
breakthrough time is obtained, while the concentration co, the
temperature T, and the relative humidity RH are kept constant.
{Claim 23}

The method according to any one of claims 18 to 22,
wherein the arithmetic processing unit is programmed in such
a manner that the breakthrough time can also be calculated by
using a relative breakthrough ratio gas of the poisonous gas
with respect to the reference.
{Claim 24}
The method according to claim 23,
wherein correction based on a dissolution rate in water in
a case where the poisonous gas is in a liquid state is made for
the calculation of the breakthrough time for which the relative
breakthrough ratio is used.