'Title of lnvcntion
LOCAL AIR CLEANING AI'PAIZATUS
5 Technical Field
[OOOl] The present invention relates to a local air cleaning apparatus.
Uackgound Art
[0002] Conventiorally, a clean bench is oflen used as an apparatus for inlproving
air cleanliness of a local work space. In a typical clean bench, only a front side ofthe
10 work bench has an opening for perforniing work and sides thereof other than the front
side form an enclosure in order to maintain cleanliness. In such a clean bench, a clean
air outlet is arranged in the enclosure, and a worker puts his or her hands therein from the
front opening for working to perform work.
[0003] However, the opening for worlcing in the clean bench is narrow.
15 Accordingly, for workers performing the assembly of precision instrunlent or the like,
there is a problenl with workability. In addition, as in a production line, when work
involves tile transfer of manufactured articles or manufacturing components, procedures
such as arrangement of the entire line in the clean room have been taken. This is,
however, problematic in ternls of increasing the size of equipment.
20 [0004] Therefore, the present inventors proposed a local air cleaning apparatus in
which air flow opening faces of a pair of push hoods capable of blowing out a uniform
flow of cleaned air are arranged opposite to each other to cause collision of air flows fron~
the respective air flow opening faces so as to allow a region between a pair of push hoods
to be a clean air space having higher cleanliness than other regions (Patent Literature 1).
25 Citation List
Patent Literature
[0005] I'atent Literature 1 : Unexarnined Japanese Patent Application Kokai
Publication No. 2008-275266.
Sumn~aryo f Invention
Technical Problem
[0006] Meanwhile, depending on the kind of work and the procedures of work, it
5 n~aybe desirable in some cases to work in a little wider clean air space. Therefore, there
has been a desire for a local air cleaning apparatus capable of forrriing a wider clean air
space.
[0007] The present invention has been acco~nplishedin view of the above problem,
and it is an objective of the present invention to provide a local air cleaning apparatus
10 capable of fonning a wide clean air space.
Solution to Problen~
[OOOS] In order to achieve the above objective, a local air cleaning apparatus
according to a first aspect of the present invention comprises:
a pair of push hoods each comprising s u a~i r flow opening face for blowing out a
15 cleaned unifonl~a ir flow and
a pair of guides each provided on a side of each ofthe push 11oods con~prisingth e
air flow opening face, each of the pair of guides extending from the side of the each push
hood comprising the air flow opening face toward a downstream side of the uniform air
flow to fo~man opening face at a dowlstrcsun-side end portion of the each guide,
20 wherein
the pair of push hoods are atranged such that the respective air flow opening faces
of the push hoods are opposed to each other;
the opening faces of the pair of guides are spaced apart from and opposed to each
other so as to form an open region between the opening faces of the respective guides;
25 and
the cleaned uniform air flows blown out from the respective air flow opening faces
collide with each other in the open region to flow out of the open region so as to cause the
insides of the guides and the inside of the open region to have higher cleanliness than
other regions.
[0009] A local air cleaning apparatus according to a second aspect of the present
invention comprises:
5 a pair of push hoods each comprising an air flow opening face for blowing out a
cleaned uniform air flow and
a guide provided on a side of one of the pair of push hoods comprising the air flow
opening face, the guide extending from the side of the one push hood comprising the air
flow opening face toward a downstream side of the uniform air flow to form an opening
10 face at a downstrean-side end portion of the guide. wherein
the pair of push hoods are arranged such that the respective air flow opening faces
of the push hoods are opposed to each other;
the opening face of the guide is spaced apart fiom and opposed to the air flow
opening face of the other push hood not provided with the guide, so as to form an open
15 region between the opening face of the guide and the air flow opening face of the push
hood not provided with the guide; and
the cleaned uniform air flows blown out fiom the respective air flow opening faces
collide with each other in the open region to flow out of the open region so as to cause the
inside of the guide and the inside of the open region to have higher clea~linestsh an other
20 regions.
101 In the local air cleaning apparatus according to the first aspect, preferably,
the respective opening faces of the guides are of substantially the same shape.
In the local air cleaning apparatus according to the second aspect, preferably, the
opening face of the guide and the air flow opening face of the push hood not provided
25 with the guide are of substantially the same shape.
Preferably, the opening face of the guide and the air flow opening face of the push
hood provided with the guide are of substantially the same shape.
Each of the pair of push hoods can comprise, for example, a plurality of push
hoods connected together.
Preferably, the cleaned unifonn air flows blown out from the air flow opening
faces have a flow rate of 0.2 to 0.7 mls.
5 Advantageous Effects of Invention
[00l I] The present invention can form a wide clean air space.
Brief Description of Drawings
[0012] FIG. 1 is a view depicting a local air cleaning apparatus according to an
embodiment of the present invention;
10 FIG. 2 is a view depicting the struc.ture of a push hood:
FIG. 3 is a view depicting another example of the local air cleanil~ga pparatus;
FIG. 4 is a view illustrating the strean of a cleaned uniform air flow;
FIG. 5 is a view depicting another example of the local air cleaning apparatus;
FIG. 6 is a view depicting another exsllple of the local air cleaning apparatus;
15 FIG. 7 is a view depicting another example of the local air cleaning apparatus;
FIG. 8 is a view depicting a local air cleaning apparatus according to another
embodiment of the invention;
FIG. 9 is a view depicting a local air cleaning apparatus according to another
e~nbodiment;
20 FIG. 10 is a view depicting a local air cleaning apparatus according to another
enlbodiment;
FIG. 1 1 is a view depicting a local air cleaning apparatus according to another
embodiment;
FIG. 12 is a view depicting nleasurement positions of Example 1 ;
25 FIG. 13 is a view depicting conditions for Examples 2 to 6; and
FIG. 14 is a view depicting measurement positions of Examples 2 to 6.
Description of Enlbodiments
[0013] Hereinafter, a local air cleaning apparatus according to the present invention
will be described with reference to the drawings. FIG. 1 is a view depicting an exai~~ple
of a local air cleaning apparatus according to an e~nbodi~neonft the present invention.
[0014] As depicted in FIG. 1, a local air cleaning apparatus 1 of the present
5 invention co~nprisesa pair of push hoods 2 and 3 arranged so as to be opposed to each
other and guides 4 and 5, respectively, provided on the respective push hoods 2 and 3.
1001 51 'She pair of push hoods 2 and 3 is not particularly limited as long as the push
hoods have a nlechanism for blowing out a cleaned unifonll air flow. As a structure of
each push hood, there can be employed a structure in which a cleaning filter is
10 incorporated in a basic structure of a push hood conventionally used in push-pull
ventilators.
[oo 161 The terms uniform air flow and uniform flow used herein have the same
meaning as uniform flow described in "Industrial Ventilation" by Taro Hayashi
(published by the Society of Ileating, Air-Conditioning and Sanitary Engineers of Japan,
15 1982) and refer to a flow having a low air velocity, which is uniformly continuous and
causes no large whirling portion. However, the present invention does not intend to
provide an air blowout apparatus strictly speciFying a flow rate of air and a velocity
distribution. In the unifornl air flow, for exanlple, a variation in a velocity distribution
in a state without obstacles is preferably within -1-50%, and furthennore within -1-30%,
20 with respect to the average value.
fool71 In the push hoods 2 and 3 of the present enlboditnent, respective nine
(longitudinal thee pieces x transversal three pieces) push hoods are connected by a
connector in such a manner that the air flow opening faces of the push hoods are oriented
in the same direction and s1101t sides and long sides, respectively, of the push hoods are
25 arranged adjacent to each other. I-ierein, structures of the push hoods connected by the
connector are basically the same. Accordingly, a description will be given of the
structure of a push hood 2a as one of the push hoods, thereby describing the structures of
the push hoods 2 and 3 of the present embodiment. FIG. 2 depicts the structure of the
push hood 2a.
[00 181 As depicted in FIG. 2, a housing 21 of the push hood 2a is formed into a
substantially rectangular parallelepiped shape, and an air flow suction face 22 is follned
5 on one surface of the housing 2 1. The air flow suction face 22 comprises, for example,
a face having a plurality of holes formed entirely on the one surface of the housing 21.
'Through the holes, the air flow suction face 22 takes in an outside air or a room air, which
is a surrounding air outside the push hood 2a. I11 addition, on the other surface of the
housing 21 opposing the air flow suction face 22 is fornicd an air blowout face (an air
10 flow opening hce) 23. The air flow opening face 23 comprises, for example, a face
with a plurality of holes fonned entirely on the one surface of the housing 21. Through
the holes, the air flow opening face 23 blows out the uniform air flow of a cleaned air
formed in the push hood 2a to the outside of the push hood 2a. The dimensions of the
air flow opening face 23 of the push hood 2a are not particularly limited, for example,
15 1050 x 850 mm.
[00 191 The push hoods 2 and 3 are arranged such that the respective air flow
opening faces 23 are opposed to each other. Herein, the description "the respective air
flow opening faces 23 are opposed to each other" mean not only a state in which the
respective air flow opening faces 23 of the push hoods 2 and 3 are opposcd in parallel to
20 each other, hut also, for example, a state in which the air flow opening face 23 of the push
hood 2 and the air flow opening face 23 of the push hood 3 are slightly inclined fron~
each other, as depicted in FIG. 3. Regarding the inclination between the air flow
opening face 23 of the push hood 2 and the air flow opening face 23 of the push hood 3,
an angle formed by the respective air flow opening faces 23 is preferably in a range of
25 about 10 degrees. In addition, as depicted in FIG. 7, a state in which while air flows
blown out from the mutual opening faces collide head on with each other, the center axes
of the air flows are tilted is also included in the state in which the respective air flow
opening faces 23 are opposed to each other.
[0020] Inside the housing 21 are arranged an air blowing mechanism 24, a high
performance filter 25, and a rectification mechanisnl26.
The air blowing mechanism 24 is arranged on a side where the air flow suction
5 face 22 is located in the housing 21. The air blowing mechanism 24 comprises an air
suction fan and the like. The air blowing mechanism 24 takes in an outside air or a
room air, which is the surrounding air of the push hood 2a, kern the air flow suction face
22 and blows out an air flow from the air flow opening face 23. In addition, the air
blowing mechanism 24 is configured to control a suction force of the fan so as to allow
10 the flow rate of an air flow blown out fio111 the air flow opening face 23 to be changed.
Loo2 1 1 The high perfon~lancefi lter 25 is arranged between the air blowing
mechanisnl24 and the rectification mechanism 26. The high performance filter 24
comprises a high performance filter corresponding to a cleaning level, such as a NEPA
filter (High Efficiency Particulate Air Filter), for filtrating the surrounding air taken in.
15 The high performance filter 25 cleans the surrounding air taken in by the air blowing
mechanism 24 into a clean air having a desirable cleaning level. The clean air cleaned
to the desirable cleaning level by the high performance filter 25 is sent to the rectification
nlechanism 26 by the air blowing mechanism 24.
roo221 The rectification mechanism 26 is arranged between the high perfonl~mlce
20 filter 25 and the air flow opening face 23. The rectification mechanism 26 is provided
with a not-shown air resistor. The air resistor is a blown-air resistor for correcting a
blown air having an amount of aeration biased with respect to an entire part of the air
flow opening face 23 into a unihrmized air flow (a unifolm air flow) having an amount
of aeration unbiased with respect to the entire part of the air flow opening face 23. The
25 air resistor is formed using a punching plate, a mesh member, and/or the like. The
rectification mechanism 26 corrects (rectifies) a clean air sent from the high performance
filter 25 into a uniformized air flow (a uniform air flow) having an amount of aeration
unbiased with respect to the entire part of the air flow opening face 23. The rectified
uniforrn air flow is blown out by the air blowing mechanism 24 from the entire part of the
air flow opening face 23 to the outside of the push hood 2.
[0023] In addition, as depicted in FIG. 2, the push hood 2a is preferably provided
5 with a pre-filter 27 between the air flow suction face 22 and the airblowing ~nechanism
24 in the housing 21. An example ofthe pre-filter 27 inay be a medium performance
filter. The arrangement of the pre-filter 27 between the air flow suction face 22 and the
air blowing mechanis~n2 4 allows removal of relatively large dust particles contained in a
surrounding air sucked into the housing 21 through the air flow suction face 22. In this
10 maIlilel; dust particles can be removed in multiple stages in accordance wit11 the size of
dust particles contained in the surrounding air. Accordingly, the performance of the
high performance filter 25 easily causing clogging or the like can be maintained for a
long period.
[0024] In the push hood 2a thus fomnled, the surrounding air laken in by the air
15 blowing mechanism 24 is cleaned into a clean air having a desirable cleaning level by the
pre-filter 27 and the high performance filter 25. Then, the clean air obtained by the
cleaning is rectified into a uniform air flow by the rectification mechanism 26. The
uniform air flow thus cleaned is blown out externally from the entire part ofthe air flow
opening face 23 in a direction substantially vertical to the air flow opening face 23 of the
20 push hood 2a.
[0025] One ends ofthe guides 4 and 5 are provided on sides of the push hoods 2
and 3 having the air flow opening faces 23. In addition, the guides 4 and 5 are provided
on the air flow opening faces 23 and formed in such a manner as to extend therefkom
toward downstream sides of uniform air flows blown out fro111 the air flow opening faces
25 23 and cover outer peripheral outline portions of the air flow opening faces 23. For
example, when the air flow opening faces 23 are rectangular, the guides 4 and 5 are
fornled to be extended so as to have a U-shape. With an open side of the U-shape and a
floor, each of the guides 4 and 5 including the outer peripheral outline portion in a
blowout direction of the unifonn air flow surrounds, like a tunnel, the periphery of the air
flow in parallel to a stream of the uniform air flow blown out therefio~n. Additionally,
when there is no floor, the guides 4 and 5 are fonned to be extended so as to have, for
5 example, square shapes, not U-shapes. These guides 4 and 5 are fonned so as to have
an open region between the respective other ends (the opening faces 41 and 51). Ikrein,
the opening faces 41 and 5 1 of the guides 4 and 5 refer to hollow end faces, nanlely
openings, which are surrounded by peripheral edge outlines of downslreanl-side end
portions (boundaries with the open region) of the guides 4 and 5 extending like the tunnel
10 toward the downstream sides of the uniforrn air flows blown out from the air flow
opening faces 23. For example, in a case of substituting the floor for a part of the guides
4 and 5, when the cross sections of the guides 4 and 5 are U-shaped, square hollow
openings formed by the downstream-side end portions of the guides 4 and 5 and the floor
correspond to the opening faces 41 and 5 1. When the cross sections of the guides 4 and
15 5 are square shaped, square hollow openings formed at the downstream-side end portions
of the guides 4 and 5 correspond to the opening faces 41 and 5 1.
[0026] The guides 4 and 5 can be formed using an arbitrary material as long as air
flows blown out fio~nth e opening faces 41 and 5 1 can maintain the state of cleaned
uniform air flows blow1 out from the air flow opening faces 23. In addition, the guides
20 4 and 5 do not ~lecessarilyh ave to completely cover the entire peripheries of the uniform
air flows as long as the state of the cleaned unifor~na ir flows blown out from the air flow
opening faces 23 can be maintained. For example, a hole nlay be opened or a slit may
be formed, partially in the guides 4 and 5.
[0027] Preferably, the opening faces 41 and 5 1 are fonned so as to have
25 substantially the same shape. When the uniform air flows collide head on with each
other, the mutual air flows do not intermingle with each other and exhibit a behavior of
substantially vertically changing the directions of the flows, as depicted in FIG. 4. The
air flows flow as if there were a wall there. By flowing in such a manner, the air flows,
after colliding with each other, flow outside a face wl~ereth e collision occul~ed. As a
result, a clean space can be obtained in a region i?onl, as a center, the collision face of the
mutual air flows to the end portions of the mutual opening faces. By making the shape
5 of the opening face 41 substantially the same as the shape of the opening face 51, the face
where an air flow blowl out from the opening face 41 collides with an air flow blown out
from the opening face 51 has substantially the sanle size as the size of faces where the
mutual air flows flow.
[0028] However, the shapes of the opening faces 41 and 5 1 do not necessarily have
10 to be substantially the sanle as each other. For exanlple, as depicted in FIG. 5, the
opening face 5 1 may be formed to be enlarged so as to be larger than the opening face 41.
Alternatively, as depicted in FIG. 6, the opening face 5 1 may be formed to be reduced in
six so as to be snlaller than the opening face 41. Even in these cases, a clean space can
be obtained in a region from, as the center, the face where an air flow blown out from the
15 opening face 41 collides with an air flow blown out fiom the opening face 5 1 to the end
portions of the nlutual opening faces.
[00291 For example, as depicted in FIGS. 5 and 6, when making the shapes (areas)
of the opening faces 41 and 5 1 different from each other by enlarging or reducing the
width of the opening face 5 1, (width of openi~ingfa ce 5 ])/(width of air flow opening face
20 23) is preferably 0.6 to 1.4 and Inore preferably 0.8 to 1.2. Setting the width ratio of the
opening faces in the range does not extremely reduce the area for air flow collision when
the air flows blown out from the opening faces 41 and 5 1 collide with each other, so that
there can be obtained a clean space sufficient to work.
[0030] In addition, preferably, the shapes of the opening faces 41 and 5 1 are formed
25 to be substantially the same as theshapes of the air flow opening faces 23. This is
because, by making the shapes of the opening faces 41 and 5 1 substantially the same as
those of the air flow opening faces 23, the state of the uniform air flows blown out from
the air flow opening faces 23 can be easily ~naintainedi n the opening faces 41 and 5 1.
I-Iowever, the shapes of the opening faces 41 and 5 1 do not necessarily have to be
substantially the sane as those of the air flow opening faces 23. For example, as
depicted in FIGS. 5 and 6 described above, the width of the opening face 5 1 may be
5 increased or reduced to make the shape of the opening face 51 different from the shape of
the air flow opening face 23, because, even in this case, the state of the unifonn air flow
can be maintained . When increasing or reducing the width of the opening hce 5 1,
(width of opening face 5l)/(width of air flow opening face 23) is preferably 0.6 to 1.4 and
more preferably 0.8 to 1.2. This is because setting the width ratio in the range allows
10 the state of the uniform air flow blown out from the air flow opening face 23 to be
maintained in the opening face 5 1.
LO03 11 The guides 4 and 5 are arranged such that the opening faces 41 and 5 1 are
opposed to each other. This is because arranging the guides 4 and 5 such that the
opening faces 41 and 51 are opposed to each other allows the mutual air flows to collide
15 head on with each other. Herein, the description "the opening faces 41 and 5 1 are
opposed to each other" means not only a state in which the opening faces 41 and 5 1 are
opposed parallel to each other, but also, for example, a state in which, as depicted in FIG.
3, the opening face 41 of the guidc 4 and the opening face 51 of the guide 5 are slightly
inclined from each other. This is because even when air flows blown out from the
20 mutual opening faces 41 and 51 do not collide head on, a clean space can be fonlled in a
space surrounded by dotted lines in FIG. 3. An inclination between the opening face 41
of the guide 4 and the opening face 5 1 of the guide 5 (an angle formed by the respective
air flow opening faces 23) is preferably within a range of about 10 degrees. In addition,
as depicted in FIG. 7, even when air flows blown out from the mutual opening faces 41
25 and 5 1 collide head on but the center axes thereof are misaligned, a clean space can also
be fonned in a region from, as the center, the face where the mutual air flows collide with
each other to the end portions of the mutual opening faces.
[0032] A length b of the guide 4 and 5 can be any length as l o ~a~sg an open region
can be ibrnled between the opening faces 4 1 and 5 1 ofthe guides 4 and 5 by spacing the
opening faces 41 and 5 1 apart from each other and opposing to each other. The length b
of the guides 4 and 5 is preferably a predetermined length in accordance with a distance
5 X between the air flow opening face 23 ofthe push hood 2 and the air flow opening face
23 of the push hood 3, the ilow rates of the uniform air flows blown out from the air flow
opening faces 23 (the opening faces 41 and 5 I), and the like. For example, when the
distance X between the air flow opening face 23 of the push hood 2 and the air flow
opening face 23 of the push hood 3 is 12 m, the length b of the guides 4 and 5 is
10 preferably 4 m or more, for example, 4 to 5.75 m, at a flow rate of the uniform air flow of
0.7 d s . In addition, when the distance X is 12 m, the length b of the guide 3 is,
preferably, 3.25 to 5.75 mat a flow rate of the uniform air flow of 0.5 d s , 5 to 5.75 mat
0.2 m/s, and 5.5 to 5.75 mat 0.1 nils.
[0033] The guides 4 and 5 thus formed are, as depicted in FIG. 1, provided
15 (attached) from the sides of the push hoods 2 and 3 having the air flow opening faces 23
toward the respective downstreani sides of the uniform air flows and arranged such that
the opening faces 41 and 5 1 provided at the downstream-side end portions of the guides
are opposed to each other. In this manner, the open region is fonned between the
opening faces 4 1 and 5 1.
20 [0034] In the local air cleaning apparatus 1 thus fornied, a surrounding air near the
air flow suction face 22 taken in by the air blowing nlechanism 24 of each of the push
hoods 2 and 3 is cleaned by the pre-filter 27 and the high perfornlance filter 25 into a
clean air having a desirable cleaning level.. Then, the clean air obtained by the cleaning
is rectified into a uniform air flow by the rectification mechanism 26 and the cleaned
25 uniform air flow is blown out into each ofthe guides 4 and 5 from the entire part of the
air flow opening face 23.
[0035] Herein, the cleaned unifornl air flows blown out from the air flow opening
faces 23 have a flow rate of preferably 0.7 m/s or less, more preferably 0.5 rnls or less,
still more preferably 0.4 mds or less, and most preferably 0.2 to 0.1 mls. This is because
when blown out at these flow rates, the cleaned uniforn~a ir flows blown out from the air
flow opening faces 23 move in such a manner as to be extruded thro~ough the insides of the
5 guides 4 and 5 and the state of the unif'o~ltal ir flows is easily maintained in the guides 4
and 5. Fu~.themtores, lowing the flow rate can suppress noise level and power
consumption and also can reduce loads on the pre-filter 27 and the high performance
filter 25. On the other hand, in a situation in which contaminants are generated in the
cleaned space of the guide 4 or 5, the contaminants in the guide can be more quickly
10 removed at a flow rate of the unifom~a ir flow of about 0.5 m/s than at a flow rate thereof
of 0.2 m/s. Thus, according to the purpose of use, the flow rate of the uniform air flow
can be freely determined.
[0036] The cleaned uniform air flow blown out in the guide 4 passes through the
guide 4 while maintaining the state of the uniform air flow, and is blown out from the
15 opening face 41. In addition, the cleaned uniform air flow blown out in the guide 5
passes through the guide 5 while maintaining the state of the uniform air flow, and is
blown out from the opening face 5 1.
[0037] The air flow blown out from the opening face 41 collides with the air flow
blown out from the opening face 5 1 in the open region formed between the respective
20 opening faces. The air flows having collided flow outside the open region (outside the
local air cleaning apparatus 1). As a result, the region between the air flow opening
faces 23 (the inside of the guide 4, the inside of the guide 5, and the open region between
the opening faces 41 and 51) can have higher cleanliness tllan regions outside the local air
cleaning apparatus 1.
25 [0038] Herein, a compariso~wl as made between the present invention and the local
air cleaning apparatus described in Patent Literature 1. For the con~parisond, imensions
of the air flow opening faces of the push hoods in both apparatuses were set to a width of'
1050 mnl and a height of850 mm, and respectively, i~inpeu sh hoods (longitudinal three
pieces x transversal three pieces) each llaving the air flow opening face were connected
together a ~odpp osed to each other. In this case, in the local air cleaning apparatus
described in Patent Literature 1, it was confirmed that the open region was a clean air
5 space until the distance between the air flow opening faces 23 reached about 5.5 In. In
contrast, in the local air cleaning apparatus 1 of the present invention, when an open
region is provided by attaching respective guides having a length of 3.25 111, from the air
flow opening faces toward the downstrean1 sides, to the outer peripheral outline portions
of the pair of push hoods opposed to each other, in which each push hood includes nine
10 push hoods having the saille structure as those in Patent Literature 1 described above and
connected together, and setting the distance between the opening faces 41 and 5 1 to 5.5
m, like the distance between the air flow opening faces of the pair of push hoods in Patent
Literature 1 described above, the clean air space corresponds to a sum of the open region
between the opening faces 41 and 51 and the distance from the air flow opening faces of
15 the pair of push hoods to the opening faces of the respective guides. In other words, the
distance 12 m between the air flow opening faces 23 is the clean air space. Accordingly,
the local air cleaning apparatus 1 of the present invention can form a wide clean air space.
[00391 In addition, co~nparedto an open-type air cleaning apparatus using the
technology described in Patent Literature 1, even when air velocities of uniform air flows
20 blowwl out from the push hoods having the same area are the same, the present inventioil
can provide a considerably wider clean air space. Thus, even when the power
consumptions of the push hoods 2 and 3 are the sane, the amount of electricity co~lsumed
per unit area in the clean air space can be reduced. Or when cleaning of the same clean
space, air velocity can be slower than in Patent Literature 1, enabling the power
25 consumption to be reduced. Then, reduction in the air velocity can also reduce noise
due to the operation of the local air cleaning apparatus, as well as can suppress the
exhaustion of the filters for obtaining a clean air. Additionally, when the open-type
local air cleaning apparatus of Patent Literatnre 1 was installed under the above
conditions, it was confirnled that power consumption was 7200 Wand noise level was 75
dB@) in the center between the air flow opening faces 23 opposed to each other. In
contrast, when the apparatus of the present invention was used under the above
5 installation conditions (the distance between the air flow opening faces 23: 22 m; each
guide lenglh: 10 m), power co~tsumnptiona nd noise level in the center between the air
flow opening faces 23 were confirined to be equivalent to those in the apparatus of Patent
Literature 1. In other words, in Patent Literature 1, a space with a volunte of about 45
cubic meters was cleaned and the amount of electricity consumed for cleaning per cubic
10 ~netewr as about 160 W, whereas the apparatus of the present invention was confirn~edto
have cleaned a space with a volume of about 177 cubic meters and the amount of
electricity consumed for cleaning per cubic meter was confirmed to he about 41 W.
Additionally, although the present invention described above has exemplified the case in
which the distance between the air flow opening faces 23 is 22 m, increasing the distance
15 cat lead to further reduction in the power consumption per unit volume.
[0040] Furthermore, in a typical clean room, the entire room is cleaned and it is
therefore not easy to perform construction work, whereas in the local air cleaning
apparatus 1 of the present embodiment, the pair of push hoods 2 and 3 can be easily
moved. In addition, the local air cleaning apparatus 1 of the embodiment can
20 significantly facilitate layout changes in the work region, such as bending the guides 4
and 5 provided on the push hoods 2 and 3 depending on the work in a range that does no1
affect uniform air flows, re~novingth e guide of one of the push hoods, and moving an
open region fornted between the opening faces of the guides to art arbitrary position.
[0041] In addition, in the case of a typical clean room in which a worker himself or
25 herself enters a clean region to perform work, a work region for the worker is not
changed no matter how much distance between a floor on which the worker works and a
ceiling with a clean air blowing apparatus is increased. I-Iowever, in the local air
cleaning apparatus 1, a horizontal flow is used. Thus, increases of regions in the guides
4 and 5 can lead to an increase of a work region (floor area) for the worker himself or
herself entering the clean region to perform work.
coo421 Additionally, in the open region of the present embodiment, there are no
5 doors that allow a worker, a conlponent, and a manufacturing machine to pass through,
necessary in a typical clean room. Thus, cleanliness reduction in the clean air region
caused by opening of the doors does not occur and going in-and-out of a worker and
carrying-in and -out of a component or the like can be always done through the open
region. In addition, even if the insides of the guides 4 and 5 and the inside of the open
10 region are contaminated, cleaning can be perfo~med in a significantly sho11 time,
although it takes a couple of hours to perform cleaning in a typical clean room.
[0043] As described above, according to the local air cleaning apparatus 1 ofthe
present embodiment, the arrangement of the guides 4 and 5 allows the inside of the guide
4, the inside of the gnide 5, and the open region between the opening faces 41 and 51 to
15 have higher cleanliness than regions outside the local air cleaning apparatus 1, so that a
wide clean air space can be formed.
[0044] The present invention is, however, not limited to the above embodiment and
various modifications and applications can be made. Ilereinafier, a description will be
given of other embodiments applicable to the present invention.
20 [0045] While the present invention has been described with reference to the above
embodiment exemplifying the case in which the guides 4 and 5 are of the same length,
the lengths of the guides 4 and 5 may be different. Even in this case, the inside of the
guide 4, the inside of the guide 5, and the open region between the opening faces 41 and
5 1 can have higher cleanliness than regions outside the local air cleaning apparatus 1,
25 thus allowing the formation of a wide clean air space.
[00461 In the above embodiment, the case in which the respective guides 4 and 5
are provided on the push hoods 2 and 3 has been exen~plifiedto describe the present
invention. However, for example, as depicted in FIG. 8, merely, the guide 4 may be
provided on the push hood 2, and the guide 4 does not necessarily have to be provided on
the push hood 3. Even in this case, the illside of the guide 4 and the open region
between the opening face 41 and the air flow opening face 23 of the push hood 3 can
5 have higher cleanliness than regions outside the local air cleaning apparatus 1, thus
allowing the ibnnation of a wide clean air space. Accordingly, in all embodime~~tas ,
guide may be provided on both ofa pair of push hoods or on orlly one of the pair thereof.
[0047] The above embodiment has exemplified the case in which the shapes of the
guides 4 and 5 colltinuillg to the push hoods 2 and 3 are extended straightly fio111 the air
10 flow opening faces 23 of the pus11 hoods 2 and 3 toward the opening faces 41 and 51 of
the guides in order to describe the present invention. However, as depicted in FIG. 9,
the shapes of the guides may be curved in a range maintaining the state of uniform air
flows blown out from the air flow opening faces 23. Even in this case, the insides of the
guides 4 and 5 and the open region between the opening faces 41 an 5 1 can have higher
15 cleat~linessth an regions outside the local air cleaning apparatus 1, thus allowing the
formation of a wide clean air space.
[0048] In the above embodiment, the present invention has been described by
exenlplifying the case in which the push hoods 2 and 3, respectively, include respective
nine (longitudinal three pieces x transversal three pieces) push hoods conllected together
20 by a connector. However, the number of push hoods forming each of the push hoods 2
and 3 may be either 10 or more or 8 or less. For example, the pus11 hoods 2 and 3 may
include respective four (longitudinal two pieces x transversal two pieces) push hoods
connected together by a connector. In order to connect the push hoods like these
examples, the push hoods are arranged such that the air flow opening faces of the push
25 hoods are oriented in the same direction and shofl sides and long sides, respectively, of
the push hoods are adjacent to each other. In this case, preferably, the mutual push
hoods are connected together in such a manner that side faces, upper and lower faces, or
both of the side faces and the upper and lower faces of the adjacent push hoods are in an
airtight state, or the mutual push hoods are connected in an airtight state via a seal
material such as a packing interposed between the side faces, the upper and lower faces,
or both thereof of the adjacent push hoods. In addition, as depicted in FIG. 10, the push
5 hoods 2 and 3, respectively, may comprise a single push hood. Even in these cases, the
inside of the guide 4, the inside of the guide 5, and the open region between the opening
faces 41 and 51 can have higher cleanliness than regions outside the local air cleaning
apparatus 1, thus allowing the formation of a wide clean air space. Additionally, in the
local air clea~~ilinagp paratus 1, without using a floor as one face of the guides 4 and 5, the
10 shapes of the guides 4 and 5 may be made square and a work bench may be provided
between the air flow opening faces 23.
[0049] The above embodiment has described the present invention by exemplifying
the case in which, in the open region between the opening faces 41 and 5 1, the upper face
and both side faces are open. However, for example, as depicted in FIG. 1 1, upper face
15 end portions of the guides 4 and 5 may be connected to each other to form a region in
which only side faces are open. Even in this case, the region between the air flow
opening faces 23 can have higher cleanliness than regions outside the local air cleaning
apparatus 1.
[OOSO] In addition, the push hoods 2 and 3 may have a structure with casters on the
20 bottoms thereof. In this case, the push hoods 2 and 3 can be easily moved.
Additionally, the guides 4 and 5 may be units of partitions with casters, which have a
shape flexibly connectable to the push hoods 2 and 3, where the units may be covered
with a vinyl sheet. In this case, construction work can be edSy and movement of the
units can also he easy. Furthermore, the guides 4 and 5 may be formed like a vinyl
25 house extensible in a stream direction of an air flow in a shape of bellows. In this case,
the lengths of the guides 4 and 5 can be easily changed, the guides 4 and 5 can be easily
bent, and the positions of the guides 4 and 5, namely, a position for obtaining a clean
space can be easily changed.
[005 11 For example, when forming a clean zone in a corner of a room, a side wall
face and/or the floor may be substituted for a part of the guides 4 and 5.
In addition, when a part of a conveyor-like line is arranged in a clean space, the
5 part of the line intended to be cleaned may be entirely covered to be enclosed as in a
tunnel; then, a push hood (2) may be attached so as to be connected to one end oftlie
enclosed pa11 of the line, whereas the other end thereof may be kept in an open state
(opening face 41) to arrange the other push hood 3 at a position opposing the open end.
In such an example, when the line is arranged along a wall, the wall can be substituted for
10 a pat of the guide 4.
Examples
[0052] Ilereinafter, the present invention will be described in more detail wit11
reference to specific Examples of the invention.
lo0531 (Example 1)
15 Using the local air cleiu~inga pparatus 1 depicted in FIG. 1, cleanliness was
nleasured at measurcnlent positions 1 to 15 (the insides of the guides 4 and 5 and the
open region between the opening faces 41 and 51) depictcd in FIG. 12. FIG. 12 is a top
view of the local air cleaning apparatus 1. The push hoods 2 and 3, respectively, are
formed by connecting nine push hoods (longitudinal three pieces x transversal three
20 pieces) each having a width of 1050 Inn1 and a height of 850 Inn1 in such a manner that
air flow opening faces of the push hoods are oriented in the same direction and short sides
and long sides, respectively, of the push hoods are respectively arranged adjacent to each
other. The respective opening faces have dimensions of a width of 3 150 n~naln d a
height of 2550 rnnl. The measurement height of the measurement positions 1 to 15 was
25 at a position of 112 of the height ofthe push hoods 2 and 3. The measurelncnt of
cleanliness was performed using LASAIR-I1 manufactured by PMS Inc., to measure the
number of dust particles (pieces1CF) having a particle size of 0.3 pnl. Regarding
cleanliness, cases with 300 pieces/CF or less were evaluated to be high in cleanliness.
Tile length b of the guides 4 and 5, respectively, was 5 111, the distance X between the air
flow opening face 23 of the push hood 2 and the air flow opening face 23 of the push
hood 3 was 12 m, and the flow rate of a cleaned uniform air flow was 0.2 mds. In
5 addition, for reference, cleanliness was also similarly measured at measurenlent positions
16 to 18 outside the local air cleaning apparatus 1. Table 1 indicates the results.
[0054] Table 1
/ Number of Dust 1 I Number ofDust I
[0055] As indicated in Table 1, it was able to be confirmed that the arrangement of
Position
1
2
3
4
5
the guides 4 and 5 allowed the inside of the guide 4, the inside of the guide 5, and the
10 open region between the opening faces 41 and 5 1 to have higher cleanliness than the
Particles
(pieces/CF)
0
0
0
0
0
regions outside the local air cleaning apparatus 1.
[0056] (Examnples 2 to 6)
As depicted in FIG. 13, cleanliness was ~lieasuredf or cascs of changing the flow
Position
10
11
12
13 1
14
rate of the cleaned unifornl air flow and the length b of the guides 4 and 5. At that time,
Particles
(pieces/CF)
0
1
1
2
0
15 the distance X between the air flow opening face 23 of the push hood 2 and the air flow
opening face 23 of the push hood 3 was set to 12 m, as in Exanlple 1. In Example 1, the
insides of the guides 4 and 5 were able to be confirmed to have been cleaned.
Accordingly, in Examples 2 to 6, as depicted in FIG. 14, cleanliness was measured at
seven points as respective measurement positions A to G in the opening face 41, in the
20 opening face 5 1, and in the center between the opening faces 41 and 5 1, respectively.
The results are given in Tables 2 to 6. The positions of measurenletlt points A, D, and E
were the positions of 15 cm downward froin the upper edges of downstream end portions
of the guides 4 and 5 and 15 CIII inward of an air flow from the side edges of the
downstrearn end portioils of the guides. The positiorls of lneasure~nentp oints B and F
5 were at an intermediate height between the upper edge and the lower edge of each of the
downstream end portiolls of the guides 4 and 5 and at the positions of 15 c ni~nw ard of
the air flow from the side edges of the downstreanl end portions of the guides. The
positions of measurenlent points C and G were the positions of 15 cm upward in the
guides from the lower edges of the downstream end portions of the guides 4 and 5 and 15
10 c111 illward of the air flow fro111 the side edges of tl~edo wnstream end po~tionso f the
guides.
[0057] Table 2
upening race point
5 1
Center
41 I
[00581 'Table 3
Measurcnletll
point
A
B
I;
Number of dust particles (pieces1CF)
0pe11ing face
51
4
12
0
C
D
E
G
Center
2
2
94
4
5 -
99
1
0
2
Opening face--
41
4
0
0
19
97
0
0
[0059] Table 4
1
Measurement
point
82 -
Number of dust particles (pieces/CF)
Opening face I Center / Opening face
[0060] Table 5
Measurement 1 upenlng rac
A 1
[0061] Table 6
:r of dust particles (picccs/CF)
I
-- .
I - . r :e
[0062] As indicated in Tables 2 to 6, it was able to be confirmed that even when the
flow rate of the cleaned uniform air flow and the length b of the guides 4 and 5 were
5 changed, the arrangement of the guides 4 and 5 allowed the opening facc 41, the ope~iing
face 5 1, and the open region between the opening faces 41 and 5 1 to have higher
cleanliness than tihe regions outside the local air cleaning apparatus 1. In Example 3, it
took 62 seconds to obtain the clean state.
100631 (Examples 7 and 8)
10 111 Example 7, cleanliness was mcasured in the same ~uannera s Example 3, except
A
B
C
D
E
pp 10
1
pp 6
0
27
I 5 .
3
0
5
4
w 2
8
5
1
that the distance between the opening faces 41 and 51 was 3.5 m, thc length b ol'the
guides 4 and 5 was 3.25 m, and the distance X between the air flow opening face 23 of
the push hood 2 and the air flow opetling face 23 of the push hood 3 was 10 111. In
Examplc 8, cleanliness was measurcd in the same manner as Example 3, except that the
5 distance between the opening faces 41 and 51 was 3.5 In and the distance X between the
air flow opening face 23 of the push hood 2 and the air flow opening face 23 of the push
hood 3 was 8 m. The results are given in Tables 7 and 8.
[0064] Table 7
[0065] Table 8
10 [0066] As indicated in Tables 7 and 8, it was able to be confirmed that even when
the distance X between Ute air flow opening face 23 of the push hood 2 and the air flow
opening face 23 ofthe push hood 3 was changed, the arrangemcnt ofthe guides 4 and 5
allowed the opening face 41, the opening face 51, and the open region between the
opening faces 41 and 51 to have higher cleanliness than the regions outside the local air
15 cleaning apparatus 1.
100671 (Examples 9 and 10)
la Example 9, cleanliness was iueasured in the sane manner as Exanlple 3, except
for using the local air cleaning apparatus depicted in FIG. 10, in which the push hoods 2
and 3, respectively, comprised a single push hood, and setting the distance between the
5 opening faces 41 and 51 to 1 In and the length b of the guides 4 and 5 to 5.5 m. In
Example 10, cleanliness was mcasured in the same manner as Exan~ple9 , except for
setting thc distance between the opening faces 41 and 5 1 to 0.5 In, the length b ofthe
guides 4 and 5 to 5.75 m, and the flow rate of the cleaned uniform air flow to 0.2 nl/s.
In addition, in Example 10, the measurement of cleanliness was perfornled only in thc
10 center between the opelling faces 41 and 5 1. The results arc given in Tables 9 and 10.
[0068] Table 9
[0069] Table 10
[0070] As indicated in Tables 9 and 10, it was able to be confirnled that even in the
cases of using the local air cleaning apparatus including the push hoods 2 and 3 each
15 comprising a single push hood depicted in FIG. 10, the arrangement of the guides 4 and 5
allowed the opcning face 41, the opening face 5 1, and the open region between the
opening faces 41 and 5 1 to have higher clea~linessth an thc regions outside the local air
clcaning apparatus 1.
LO0711 (Exanlples 11 and 12)
5 in Example 1 1, cleanliness was measured in the same miuuler as Exan~ple3 ,
except for using the local air cleaning apparatus depicted in FIG. 8 in which the guide 4
was provided only on the push hood 2 and setting the length b of the guide 4 to 9 m. In
Example 12, cleanliness was measured in the same manner as Example 11, except for
setting the length b of the guide 4 to 6.5 m. Measurement points were the same as those
10 in Example 3. However, on the side of the apparatus having only the push hood. the
measurement points were regarded as measurement points for a case of using the air flow
opening face of the push hood 3 instead of the opening face 5 1, like the guide 5. The
results are given in Tables 11 and 12.
[0072] Table 11
[0073] Table 12
easurernen
Measurement
point
A
Number of dust particles (pieces1CF)
Air flow opening
face 23 Center
Opening
face 4 1
n J n n
100741 As indicated in Tables I1 and 12, it was able to be confirmed that even in
the case of using the local air cleaning apparatus in which the guide 4 was provided only
on the push hood 2 depicted in FIG. 8, the arrangenierit of the guide 4 allowed the
opening face 41, the air flow opening face 23 of the push hood 3, and the open region
5 between the opening face 41 and the air flow opening face 23 of the push hood 3 to have
higher cleanliness than the regions outside the local air cleaning apparatus 1.
[0075] (Examples 13 and 14)
In Example 13, cleanliness was measured in the same manner as Exanlple 3,
except for using the local air cleaning apparatus depicted in FIG. 5 in which the opening
10 face 5 1 was enlarged to be larger tllan tihe opening face 41 and setting the distance
between the opening faces 41 and 51 to 3 n~ and the length b of the guide 4 to 4.5 m.
Regarding measurements points in this case, cleanliness in the center and the opening
face 41 was measured at positions based on the guide with the opening face 41, and
cleanliness in the opening face 5 1 was measured at positions based on the opening face
15 5 1. In Example 14, cleanliness was measured in the same manner as Example 3, except
for using the local air cleaning apparatus depicted in FIG. 6 in which the opening face 51
was reduced in size to be smaller than the opening face 41 and setting the distance
between the opening faces 41 and 51 to 3 nl and the length b of the guide 4 to 4.5 in.
Regarding measurement points in this case. cleanliness in the center and the opening face
20 41 was measured at positions based on the guide with the opening face 41, and
cleanliness in the opening face 51 was measured at positions based on the opening face
5 1. The results are given in Tables 13 and 14.
[0076] Table 13
Measurement
point
A
B
C
D
Number of dust pafiicles (pieces/CF)
Opening face
4 1
14
195 -
2
0
Opening face
51
1
0
0
0
Center
0
2
9
1
[007X] As indicated in Tables 13 and 14, it was able to be confirmed that eve11 in
the cases of using the local air cleaning apparatus including the opening face 5 1 enlarged
1;
G
to be larger than the opening face 4 1 depicted in FTG. 5 and the local air cleaning
5 apparatus including the opening face 5 1 reduced in size to be smaller than the opening
face 41 depicted in FIG. 6, the arrangement of the guides 4 and 5 allowed the opening
face 41, the opening face 5 1, and the open region between the opening faces 41 and 51 to
have higher cleanliness than the regions outside the local air cleaning apparatus 1.
[0079] (Example 15)
10 In Example 15, cleanliness was measured in the same n~annera s Exanlple 3,
except for using a local air cleaning apparatus depicted in FIG. 11 in which the end
portions of upper surfaces of the guides 4 and 5 were connected to foml a region with
only both side faces open and setting the length b of the guide 4 to 5 111 and the flow rate
to 0.2 m/s. The results are given in Table 15.
15 fOOXOl Table 15
[0077] Table 14
- 2
2
0
1
1
Measurement
point
--A
- B
C
D
1
4
22
Number of dust particles (pieces1CF)
Opening face
41
20
0
0
0
Opening face
51
10
0
15
0
Center
0
0
0
0
the center between the opening faces. The results are given in Table 16.
15 100831 Table 16
20
0
30
[0081] As indicated in Table 15, it was able to be confirmed that even in the case of
using the local air cleaning apparatus including the guides 4 and 5 whose upper surface
end portions were connected to form the region with only both side faces open depicted
in FIG. 1 1, the arrange~nenot f the guides 4 and 5 allowed the opening face 41, the
5 opening face S I , and the open region between the opening faces 41 and 5 1 to have higher
cleanliness than the regions outside the local air cleaning apparatus 1.
[0082] (Examples 1, 16, and 17)
I