Technical Field
The present invention relates to an analyzer calibrating system capable of concurrently
calibrating a plurality of analyzers and an exhaust gas analyzing system using the
5 analyzer calibrating system.
Background Art
An exhaust gas analyzer for analyzing exhaust gas exhausted from an engine of
a vehicle or the like is used in arrangement in each of a plurality of test chambers. In
lo each of the test chambers, an engine of such as a vehicle serving as a specimen is
installed.
Then, in the case of calibrating these exhaust gas analyzers, it is necessary to
supply calibration gas for zero calibration or span calibration to flow through the
15 exhaust gas analyzers. In this arrangement, since a calibration gas cylinder storing the
calibration gas is in a state of high pressure, the calibration gas cylinder is usually
provided in a gas cylinder chamber separated from the test chambers. In addition,
since the calibration gas is supplied to a plurality of exhaust gas analyzers from the
• calibration gas cylinder in common, the number of cafibration gas cylinders is reduced.
However, in the conventional case where the calibration gas is concurrently
supplied from one calibration gas cylinder to a plurality of exhaust gas analyzers to be
calibrated, calibration time is uniformly set for all of the exhaust gas analyzers. In
addition, during this calibration time, it is configured to render the calibration gas to
25 flow into all of the exhaust gas analyzers.
In this arrangement, a time until an output value of each exhaust gas analyzer
becomes stable is different depending on a length of a calibration gas pipe between the
calibration gas cylinder and the exhaust gas analyzer and a status of a contact gas
surface of the calibration gas pipe or piping conditions such as a material of the
5 calibration gas pipe and a situation of such as an instaIlation environment of each of the
exhaust gas analyzers. For example, in an exhaust gas analyzer having a lengthy pipe
from the calibration gas cylinder, it takes a long time for the calibration gas to reach the
exhaust gas analyzer so that the time to stabilize the output value of the exhaust gas
analyzer is accordingly increased. Moreover, as described above, in the case where the
10 calibration time is uniformly set for all of the exhaust gas analyzers, it is necessary also
for an exhaust gas analyzer having completed with the calibration with the output value
already stabilized to wait for a lapse of the calibration time, and there arises a problem
that a start of a measurement of the exhaust gas using the exhaust gas analyzer is
delayed. Furthermore, in spite that the calibration can be early finished for the exhaust
15 gas analyzer having completed with the calibration with the output value already
stabilized, the calibration gas is unnecessarily continued to flow into the exhaust gas
analyzer, and there arises also a problem that the calibration gas is consumed in waste.
@ Citation List
20 Patent Literature
Patent Literature 1 : JPA Hei 08-23373 8
Summary of Invention
Technical Problem
25
Therefore, the present invention has been made in order to solve the problems
at a stroke and its essential object is to reduce the calibration time and consumption
amount of calibration gas in the case of concurrently calibrating a plurality of analyzers.
5 Solution to Problem
That is, an analyzer calibrating system according to the present invention is
characterized by including: a calibration gas line for concurrently supplying the same
calibration gas to a plurality of analyzers; and a control unit adapted to determine
0 10 whether or not an output value of each of the plurality of analyzers supplied with the
same calibration gas is stable, whereby the control unit calibrates the analyzer having
the output value determined to be stable and stops the supply of the calibration gas to
the analyzer having completed with the calibration. It is noted here that the phrase
"concurrently supplying the same calibration gas to a plurality of analyzers" means not
15 only an idea of starting the supply of the calibration gas to a plurality of analyzers at the
same time but also includes an idea that there is a time period of supplying the
calibration gas to a plurality of analyzers at the same time during a calibration process
even in the case where the starting times of supplying the calibration gas to a plurality
@ of analyzers are different.
20
With this configuration, the calibration gas for a plurality of analyzers can be
concurrently supplied via the calibration gas line so that the plurality of analyzers can be
concurrently calibrated. In addition, since the control unit determines whether or not
an output value of each of the plurality of analyzers is stable and calibrates the analyzer
25 having the output value determined to be stable so that the supply of the calibration gas
4
to the analyzer having completed with the calibration is stopped, the calibration time
can be optimized for every analyzer so that the calibration time in total can be reduced.
Further, since the calibration gas is not supplied in waste to the analyzer having
completed with the calibration, the consumption amount of the calibration gas can be
5 reduced.
As a simple and easy configuration for individually switching the supply and
stop of the calibration gas to a plurality of analyzers, it may be considered that the
calibration gas line includes a plurality of branch lines respectively provided in a
10 one-to-one correspondence with the plurality of analyzers and a plurality of odoff
valves respectively provided on the plurality of branch lines. In this configuration, it is
preferable that the control unit controls the odoff valve provided on each of the branch
lines to thereby stop the supply of the calibration gas to the analyzer having completed
with the calibration.
15
In order to optimize the calibration time of the plurality of analyzers in any of
the zero calibration and the span calibration, it is preferable that the calibration gas line
includes a zero gas line for supplying zero gas for zero calibration to the plurality of
analyzers and a span gas line for supplying span gas for span calibration to the plurality
20 of analyzers and the control unit is configured to carry out the zero calibration using the
zero gas and the span calibration using the span gas in this order.
Advantageous Effects of Invention
According to the present invention configured as described above, it becomes
25 possible to reduce the calibration time together with the consumption amount of the
5
calibration gas in the case of concurrently calibrating a plurality of analyzers.
Brief Description of Drawings
Fig. 1 is a schematic diagram showing a configuration of an exhaust gas
5 analyzing system of the present embodiment;
Fig. 2 is a schematic diagram showing a single calibration gas line of the same
embodiment;
Fig. 3 is a flowchart of a calibration process of the same embodiment; and
Fig. 4 is a schematic diagram showing a calibration method of the same a 10 embodiment.
Description of Embodiments
The following describes one embodiment of an exhaust gas analyzing system
15 according to the present invention with reference to the accompanying drawings.
As shown in Fig. 1, the exhaust gas analyzing system 1 of the present
embodiment includes: a plurality of exhaust gas analyzing apparatuses 2 respectively
• provided in a plurality of test chambers TRl to TR3 in Fig. 1 in each of which an engine
20 of a vehicle or the like is installed to analyze the exhaust gas exhausted from the engine;
and an analyzer calibrating system 3 for calibrating the plurality of exhaust gas
analyzing apparatuses 2. In the arrangement of the plurality of exhaust gas analyzing
apparatuses 2, lengths of calibration gas pipes from a calibration gas cylinder 6 as to be
described later, statuses of contact gas surfaces of the calibration gas pipes or piping
25 conditions such as materials of the calibration gas pipes and installation environment of
6
each of the exhaust gas analyzers are different from each other.
In specific, the exhaust gas analyzing apparatus 2 is equipped with a plurality
of analyzers having, for example, different measurement principles so as to be able to
separately measure each component such as HC, NOx, CO, C02 and the like contained
5 in the exhaust gas. In addition, the analyzer configurations of the exhaust gas
analyzing apparatus 2 arranged in each of the test chambers TRl to TR3 may be
identical to each other or may include an analyzer which is pertly different. It is noted
that the plurality of exhaust gas analyzing apparatuses 2 send and receive various kinds
of data such as analysis data, schedule data and the like to and from a central a 10 management device (not shown) located in a measurement chamber partitioned from the
test chambers TRl to TR3 via such as a LAN.
As shown in Figs. 1 and 2, the analyzer calibrating system 3 includes: a
plurality of calibration gas lines 4 provided for respective different kinds of calibration
15 gas for concurrently supplying the calibration gas to the plurality of exhaust gas
analyzing apparatuses 2; and a control unit 5 for controlling the calibration gas lines 4
and carrying out calibration processes of the plurality of exhaust gas analyzing
apparatuses 2.
20 In this arrangement, as the different kinds of calibration gas, there are used zero
gas for zero-calibrating the analyzer 2% span gas for span-calibrating the analyzer 2x
and the like and these different kinds of calibration gas are respectively supplied to
different analyzers 2x of each exhaust gas analyzing apparatus 2. It is noted here that
the reference numeral 2x shown in Fig. 2 denotes the identical analyzers that are
25 calibrated using the same calibration gas in common to the plurality of exhaust gas
7
analyzing apparatuses 2.
The calibration gas line 4 of the present embodiment includes: a zero gas line
4a for supplying zero gas for zero-calibrating the same analyzers 2x in the plurality of
exhaust gas analyzing apparatuses 2 to the corresponding analyzers 2x; and a span gas
5 line 4b for supplying span gas for span-calibrating the same analyzers 2x in the plurality
of exhaust gas analyzing apparatuses 2 to the corresponding analyzers 2x. It is noted
here that these zero gas line 4a and span gas line 4b are prepared for every kind of the
analyzers 2x.
Especially as shown in Fig. 2, each calibration gas line 4 (4a, 4b) has its one
end connected to a calibration gas cylinder 6 for storing the calibration gas, and includes
a plurality of branch lines 41 branched in a one-by-one correspondence with the
plurality of analyzers 2x in a downstream side thereof and further includes a plurality of
onfoff valves 42 such as solenoid valves respectively provided on the plurality of branch
15 lines 41. The plurality of branch lines 41 are respectively provided for the same
analyzers 2x constituting the exhaust gas analyzing apparatuses 2 respectively provided
in the test chambers TRl to TR3. The calibration gas cylinder 6 connected with each
calibration gas line 4 is arranged in a cylinder chamber BR partitioned from the test
chambers TRl to TR3 and the measurement chamber.
The control unit 5 is adapted to determine whether or not an output value of
each of the plurality of analyzers 2x is stable and calibrate the analyzer 2x having the
output value determined to be stable, and then stops the supply of the calibration gas to
the analyzer 2x having completed with the calibration thereof by controlling the
25 calibration gas line 4.
Further, the control unit 5 continuously carries out the zero calibration using
the zero gas and the span calibration using the span gas in this order. Then, in any of
the zero calibration and the span calibration, the control unit 5 individually determines
5 whether or not the output value of every analyzer 2x and controls each of the ordoff
valves 42 of the respective branch lines 41 to thereby switch the supply and stop of the
calibration gas every analyzer 2x. It is noted that, as an equipment configuration of the
control unit 5, it may be configured to fbnction by a computer including, for example, a
CPU, memory, VO interface, AD converter, display and the like, or may be configured 0 10 to function by a plurality of computers physically separated. Also, the functions of the
control unit 5 may be provided in the central management device.
Specifically, the control unit 5 is adapted to control each of the onloff valves 42
on the branch lines 41 to thereby introduce the calibration gas to the plurality of
15 analyzers 2x. That is, as shown in Fig. 3, at the time of starting the calibration process
of the plurality of analyzers 2x, the control unit 5 opens an output port of the calibration
gas cylinder 6 to be supplied to the analyzer 2x to be calibrated and opens the ordoff
valve 42 provided on the branch line 41 of the calibration gas line 4. Thus, the supply
of the calibration gas to the plurality of analyzers 2x is started at the same timing (Step
20 Sl).
Next, the control unit 5 acquires output value data obtained by the plurality of
analyzers 2x supplied with the calibration gas (Step S2) and determines whether or not
the output value of each of the plurality of analyzers 2x is stable (Step S3).
25 Specifically, as shown in Fig. 4, after starting the supply of the span gas as the
9
calibration gas, it is determined at predetermined time intervals whether or not the
output value of each analyzer 2x is stable. The determination of stability of the output
value is performed based on whether or not a predetermined condition is satisfied. In
the present embodiment, the determination is performed based on whether or not a
5 time-based variation width of the output value is within a predetermined range such as,
for example, within 0.1 % with respect to, for example, a full scale of the analyzer 2x.
Then, according to the above determination, in the case where it is determined that the
output value is stable, the output value and a known component concentration of the
e span gas are compared using the output valued thereafter to thereby perform the
10 calibration of the analyzer 2x (Step S4). Meanwhile, in the case where the output value
is not stable, the calibration gas is kept flowing until the output value is stable. The
above is a calibration process of each analyzer. In Fig. 4, although the span calibration
after the zero calibration is shown, the zero calibration performed before the span
calibration is similarly performed. It is noted that, in Fig. 4, although a waiting time is
15 set in consideration of replacement of the gas from the zero gas to the span gas at the
time of starting the span calibration process after completion of the zero calibration, the
stability of the output value may be determined at a predetermined time interval using a
span calibration process starting point as a starting point without setting a waiting time.
20 After the above calibration is completed, the control unit 5 closes the onloff
valve 42 on the branch line 41 connected to the analyzer 2x upon completion of the
calibration thereof, thereby stopping the supply of the calibration gas to the analyzer 2x
(Step S5). Regarding the analyzer 2x upon completion of the calibration thereof, the
next exhaust gas measurement can be performed. Meanwhile, the control unit 5
25 continuously keeps the calibration process as to the analyzer 2x having not yet
10
completed with the calibration. That is, as described above, it is determined at a
predetermined time intervals whether or not the output value of each of the analyzers 2x
is stable (Step S3), and in the case where the output value is stable, the output value and
the known component concentration are compared using the output value thereafter to
5 thereby perform the calibration of the analyzer 2x (Step S4). Thus, the respective
completion times of the calibrations of the plurality of analyzers 2x are determined
independently determined each other. When the calibration processes of the whole
analyzers 2x are respectively completed (Step S6), the calibration processes of the
plurality of analyzers 2x are finished.
10
According to the exhaust gas analyzing system 1 according to the present
embodiment configured as described above, the plurality of analyzers 2x can be
concurrently calibrated by concurrently supplying the calibration gas to the plurality of
analyzers 2x via the calibration gas line 4. In addition, since the control unit 5
15 individually determines whether or not an output value of each of the plurality of
analyzers 2x is stable and calibrates the analyzer 2x having the stable output value and
then stops the supply of the calibration gas to the analyzer 2x upon completion of the
calibration thereof, the calibration time can be optimized every individual analyzer 2x
so that the calibration time can be reduced. Furthermore, since the calibration gas is
20 not rendered to flow through the analyzer 2x having the stable output value in waste, the
consumption amount of the calibration can be reduced.
It is noted that the present invention should not be limited to the above
embodiment.
25
For example, in the present embodiment, although in any of the zero calibration
and the span calibration the plurality of analyzers are individually calibrated and the
supply of the calibration gas to the analyzers is stopped in sequence from the analyzer
having completed with the calibration, any one of the zero calibration or the span
5 calibration may be applied. In addition, as the span calibration, multi-point calibration
may ne performed using calibration gas of different concentrations.
In the embodiment, although the start of supplying the calibration gas are made
a at the same time to all of the plurality of analyzers to be supplied with the same
10 calibration gas, the starting times of supplying the calibration gas to all of the plurality
of analyzers to be supplied with the same may be different and there may be a time
period in which the calibration gas is concurrently supplied to all of the plurality of
analyzers during the calibration process. Furthermore, the start of supplying the
calibration gas to at least two or more of the plurality of analyzers to be supplied with
15 the same calibration gas is made at the same time and there may be a time period in
which the calibration gas is concurrently supplied to all of the plurality of analyzers
during the calibration process.
In addition, the calibration gas line may be adapted to concurrently supply the
20 calibration gas to all of the plurality of analyzers to be supplied with the same
calibration gas, and also may be adapted to concurrently supply the calibration gas to a
part (at least two) of the plurality of analyzers.
Furthermore, the calibration of one analyzer may be also performed using the
25 analyzer calibrating system of the present embodiment.
In addition, the present invention should not be limited to the above
embodiment, and various modifications are of course possible within the scope unless
departing from the intended spirit thereof.
5
Reference Signs List
1 . . . Exhaust gas analyzing system
2 . . . Exhaust gas analyzing apparatus
2x . . . Analyzer
10 3 . . . Analyzer calibrating system
4 . . . Calibration gas line
4a . . . Zero gas line
4b . . . Span gas line
41 . . . Branch line
15 42 ... Onloff valve
5 . . . Control unit
6 . . . Calibration gas cylinder

CLAIMS
We Claim:
1. An analyzer calibrating system (3) characterized by comprising:
5 a calibration gas line (4) for concurrently supplying the same calibration gas to
a plurality of analyzers (2x); and
a control unit (5) adapted to determine whether or not an output value of each
of the plurality of analyzers supplied with the same calibration gas is stable, whereby
the control unit calibrates the analyzer having the output value determined to be stable
10 and stops the supply of the calibration gas to the analyzer having completed with the
calibration.
2. The analyzer calibrating system as claimed in claim 1, wherein the
calibration gas line comprises a plurality of branch lines respectively provided in a
15 one-to-one correspondence with the plurality of analyzers and a plurality of odoff
valves respectively provided on the plurality of branch lines, and wherein
the control unit controls the odoff valve provided on each of the branch lines
to thereby stop the supply of the calibration gas to the analyzer having completed with • the calibration.
20
3. The analyzer calibrating system according to claim 1, wherein the calibration
gas line comprises
a zero gas line (4a) for supplying zero gas for zero calibration to the plurality of
analyzers and a span gas line (4b) for supplying span gas for span calibration to the
25 plurality of analyzers, and wherein
the control unit is configured to cany out the zero calibration using the zero gas
and the span calibration using the span gas in this order.
4. An exhaust gas analyzing system (I), comprising the analyzer calibrating
5 system (3) as claimed in claim 1.