JP6122890B2 - Test gas generator - Google Patents

Description

  The present invention relates to a test gas generation device that generates a test gas containing hydrogen gas at a predetermined hydrogen gas concentration, and more particularly to a test gas generation device that has a simple structure and an accurate content rate.

  Currently, hydrogen gas vehicles that store hydrogen gas and use it as fuel, and fuel cell vehicles that run on motors for power generation of fuel cells are being put into practical use. In particular, fuel cell vehicles include in-vehicle hydrogen sensors. It is installed as a gas leak detector, and detects hydrogen leaking from hydrogen pipes, etc., and issues an alarm or shuts off the main valve of the hydrogen container.

In order to inspect such an in-vehicle hydrogen sensor, there is a demand to check the operation of the in-vehicle hydrogen sensor by generating a hydrogen / air mixed gas on site and spraying it on the in-vehicle hydrogen sensor installed in the fuel cell vehicle. There is a need for a test gas generator that can be easily verified on site.
However, a high-precision test gas generation apparatus obtained by using existing technology is a stationary large-sized apparatus or expensive due to its complicated structure, and is inconvenient to use in the field. .

  By the way, it is described in 3.9.5 of "Technical Standards for Fuel System of Automobiles Fueled with Compressed Hydrogen Gas" (Attachment 100) In addition, “Attachment 3” states that “a gas having a hydrogen concentration of 3.9% ± 0.1% in which hydrogen is mixed with air is used” as the test gas used for the test of the hydrogen gas leak detector. Has been.

  BACKGROUND ART Hydrogen sensors that detect leakage of flammable gas containing hydrogen into the air have been widely used in applications other than automobiles, particularly in chemical plants and ironworks. Most of them are of the catalytic combustion type or the semiconductor type, both of which are made to operate in an air atmosphere.

Normally, flammable gas detectors are set to alarms at about 1/3 of the lower explosion limit concentration of the gas to be detected, so for hydrogen, the alarm setting is around 1.3%, which is 1/3 of the lower explosion limit concentration of 4%. Has been value. The concentration of 1.3% (1/3 of the explosion lower limit concentration of 4%) is consistent with the upper limit concentration that is permitted to be manufactured as a standard gas containing oxygen such as an air base due to safety restrictions.
Thus, when testing or calibrating conventional hydrogen sensors in applications other than automobiles, 1.3% air-based hydrogen standard gas has been widely used.

  However, according to the above technical standards, the gas used for the test of the on-vehicle hydrogen sensor mounted on the fuel cell vehicle is “hydrogen in which hydrogen is mixed with air”, that is, hydrogen containing oxygen, and its concentration is 3. Since it is defined as 9% ± 0.1%, the standard gas contained in the container cannot be manufactured, and the test gas must be prepared by another means.

  In the prior art, when a test gas is generated by mixing hydrogen gas and a dilution gas in order to obtain a test gas, a test gas containing hydrogen gas at a desired concentration is obtained using a mass flow controller. Technology has been developed.

  However, even if an attempt is made to obtain a test gas having a desired hydrogen gas concentration by controlling the flow rate of the hydrogen gas and the flow rate of the dilution gas, it is difficult to adjust the hydrogen gas concentration to an accurate value. There is a problem that the cost is high.

A technique for creating a test standard gas is described in, for example, Patent Document 1 below.
In addition, as a technique that does not use a mass flow controller, for example, there is a device described in Patent Document 2 below. However, since this device becomes a complicated ventilation circuit including a supply switching device, a storage device, and the like, The waiting time until the concentration becomes stable is long, and it has been difficult to make an inexpensive and portable small device.

JP 2012-141292 A Japanese Patent No. 5670530

  The present invention was created to solve the above-described disadvantages of the prior art, and the present invention provides a test gas generation apparatus that can generate a test gas with a small, light and accurate hydrogen gas concentration. Let it be an issue.

In order to solve the above problems, the present invention provides a hydrogen gas passage through which hydrogen gas supplied from a hydrogen gas source passes, a dilution gas passage through which dilution gas supplied from a dilution gas source passes, the hydrogen gas passage, A merged portion where the dilution gas flow path merges, the hydrogen gas flowing in from the hydrogen gas flow path and the dilution gas flowing in from the dilution gas flow path, and a mixed gas generated in the merged section A suction pump that sucks with suction force and supplies it to the output unit, a hydrogen gas resistor provided in the hydrogen gas flow path and restricting the flow of the hydrogen gas through the hydrogen gas flow path, and the dilution gas A dilution gas resistor that restricts the flow of the dilution gas through the dilution gas channel; a hydrogen sensor that detects a hydrogen gas concentration of the mixed gas; and the suction force of the suction pump. A control device to change, Air is used as the dilution gas, and due to the differential pressure generated at both ends of the dilution gas resistor, the dilution gas flows through the dilution gas resistor and the difference generated at both ends of the hydrogen gas resistor. A dilution gas configured to cause the hydrogen gas to flow through the hydrogen gas resistor by pressure, and showing a relationship between a differential pressure across the dilution gas resistor and a flow rate of the dilution gas flowing through the dilution gas resistor the slope of the flow curve, the slope of the hydrogen gas flow rate curve showing the relationship of the hydrogen gas flow through the differential pressure and the hydrogen gas generating resistor at both ends of the hydrogen gas generating resistor is different numerical values, and the In the dilution gas resistor, the tangent line on the dilution gas flow curve does not pass through the origin in the coordinate system of the differential pressure and the dilution gas flow curve, and the intercept with the flow axis of the coordinate system is a positive value. Yes, the control device , The hydrogenated sensor detection result detected input, wherein the control device, so that the hydrogen gas concentration becomes the reference value, which is the test gas generator for changing the suction force of the suction pump.
Moreover, this invention is a test gas production | generation apparatus, Comprising: The said hydrogen sensor is a test gas production | generation apparatus which detects the hydrogen gas concentration of the said mixed gas which the said suction pump supplies to the said output part.
The invention also relates to a test gas generator, a test gas generator to atmospheric pressure of the dilution gas source is the dilution gas and the hydrogen gas source for supplying the hydrogen gas supplied.
Further, the present invention is a test gas generation device, wherein the suction pump sets the differential pressure at both ends of the hydrogen gas resistor and the differential pressure at both ends of the dilution gas resistor to a pressure of 400 Pa or more. A test gas generation device configured to suck the mixed gas with the suction force.

A test gas with a hydrogen gas concentration required when testing an on-vehicle hydrogen sensor mounted on a fuel cell vehicle according to technical standards is easily generated at the test site and supplied to the on-vehicle hydrogen sensor to be tested. be able to.
Further, since the hydrogen concentration of the generated test gas is measured and the mixing rate can be controlled, the mixing rate, that is, the hydrogen gas concentration can be accurately adjusted.

Furthermore, according to the present invention, there is an advantage that the supply gas adjusted to a constant concentration can be stably supplied, and the cost is lower and the accuracy is higher than when the mixing rate is controlled by the flow rate control by the mass flow controller.
A test gas in which hydrogen is mixed with air can be generated and supplied at a concentration of 3.9% exceeding 1.3% which is not supplied with a standard gas contained in a container.

Example of test gas generator of the present invention Graph showing the relationship between the differential pressure of the hydrogen gas resistor and the hydrogen gas flow rate Graph showing the relationship between the differential pressure of the dilution gas resistor and the dilution gas flow rate A graph showing the relationship between the differential pressure of the mixed gas and the calculated value of the hydrogen gas concentration Graph of calculated and measured hydrogen gas concentration Graph showing hydrogen gas concentration of test gas Measuring device for measuring the relationship between differential pressure and hydrogen gas flow rate Measuring device for measuring the relationship between differential pressure and dilution gas flow rate (a): First other example of hydrogen gas source (b): Second other example of hydrogen gas source

In particular, the present invention is a test gas generation device that supplies a 3.9% hydrogen / air mixed gas necessary for confirming the operation of the on-vehicle hydrogen sensor to the on-vehicle hydrogen sensor by a simpler method.
If the property of making gas difficult to flow is called a flow restriction characteristic, two ventilation resistance elements (ventilation resistors) having a flow restriction characteristic, a gas suction means, a hydrogen sensor, and a gas suction means based on a signal from the hydrogen sensor And a control means for adjusting the suction capacity.

When a gas flows between two points having a flow restriction characteristic in a flow path (pipe) through which the gas flows, the gas flow rate between the two points in the flow path is a function of the differential pressure between the two points.
When the differential pressure changes slightly, the ratio of the slight change in the differential pressure to the slight change in the gas flow rate (the slight change in the differential pressure / the slight change in the gas flow rate) indicates the flow restriction characteristic. The value is a function of the differential pressure and is based on the structure between two points and the nature of the gas.

  Regarding the contents of each component and the connection of the flow path (pipe), hydrogen gas storage is made by using a resistance element for hydrogen gas as a flow resistance element through which hydrogen gas flows, with one end kept at the same pressure as atmospheric pressure. The ventilation resistance element through which dilution gas flows is connected to hydrogen gas (for example, 100% hydrogen) stored in the apparatus, and one end thereof is connected to a dilution gas atmosphere at atmospheric pressure. Here, air is used as a dilution gas, and one end is opened to an air atmosphere.

  If the flow path through which the hydrogen gas flows through the hydrogen gas resistor, such as the internal space of the piping, is the hydrogen gas flow path, and the flow path through which the dilution gas flows through the dilution gas resistor is the dilution gas flow path, The end downstream of the hydrogen gas resistor and the end downstream of the dilution gas resistor in the dilution gas flow path are connected at the joining location, and the hydrogen gas and the dilution gas are merged to join. The mixed gas in which the hydrogen gas and the diluting gas combined at the place are mixed is sucked with a suction pump.

  The suction means sucks the mixed gas from the inlet side, discharges it from the outlet side, and supplies it to the in-vehicle hydrogen sensor. The hydrogen sensor that detects the hydrogen gas concentration, which is the content of hydrogen gas in the mixed gas, may be connected to the inlet side or the outlet side of the suction means. The hydrogen gas concentration is a value of (volume of hydrogen gas in mixed gas) / (volume of mixed gas).

  The pressure at the joining location is negative with respect to atmospheric pressure, and the concentration of hydrogen gas in the mixed gas can be made constant by increasing or decreasing the suction force of the suction means by the operation of the control means. .

  Taking the case where the hydrogen gas concentration in the mixed gas is set to 3.9% as an example, the ratio of the flow rate of the dilution gas (air) to the flow rate of the hydrogen gas only needs to be 1: 24.6. Select the flow restriction characteristics of the hydrogen gas resistor and the dilution gas resistor so that a flow ratio of 1: 24.6 is obtained in the differential pressure from the atmospheric pressure at the confluence location that can be set by the suction force of the means. do it.

  Here, hydrogen gas has a much lower viscosity resistance than the dilution gas (air) and has a smaller flow rate ratio, so the flow rate of hydrogen gas through the resistor for hydrogen gas is linearly related to the differential pressure through the origin. Holds. On the other hand, the flow rate of the dilution gas passing through the dilution gas resistor shows a non-linear relationship with respect to the differential pressure. For example, when the differential pressure is 400 Pa or more, the straight line (tangent line) in contact with the dilution gas flow curve is extended. The intercept with the flow rate axis (differential pressure = 0 Pa) does not pass through the origin and becomes a positive value.

  In other words, the relationship between the differential pressure across the hydrogen gas resistor and the flow rate of hydrogen gas flowing through the hydrogen gas resistor can be approximated as a linear expression in which the hydrogen gas flow rate becomes zero when the differential pressure is zero. On the other hand, the relationship between the differential pressure across the dilution gas resistor and the flow rate of the dilution gas flowing through the dilution gas resistor is such that the value of the flow rate limiting characteristic changes as the differential pressure changes.

  Based on the above relationship, when obtaining the hydrogen gas concentration in the mixed gas, the hydrogen gas flow rate Yh and the dilution gas flow rate Ya are determined using the variable X, the positive coefficients Kh, Ka, and the positive numerical value b. It can be expressed as the following equations (1) and (2).

Yh = Kh · X (1)
Ya = Ka ・ X + b …… (2)

  Kh is a constant, Ka is the slope of the tangent of the dilution gas flow curve at the differential pressure X, and the coefficient Kh and the coefficient Ka indicate the ratio of the flow rate change to the change in the differential pressure, which is the value for hydrogen gas The ease of flow between the resistor and the dilution gas resistor is shown. Further, the reciprocals 1 / Kh and 1 / Ka of the coefficient Kh and the coefficient Ka are flow restriction characteristics and indicate difficulty in flowing.

As the value of the differential pressure X increases, the value of the coefficient Ka decreases and the value of the intercept b increases.
The above expressions (1) and (2) may be used as approximate expressions (linear expressions) in the vicinity of the set differential pressure X (Pa).
From the equations (1) and (2), the hydrogen gas concentration R in the mixed gas can be expressed by the following equation (3).

R = Yh / (Yh + Ya) = Kh ・ X / (Kh ・ X + Ka ・ X + b)
= Kh ・ X / [(Kh + Ka) ・ X + b] = Kh / [Kh + Ka + b / X]
...... (3)

  From the above equation (3), it can be seen that as the differential pressure X increases, the denominator decreases and the hydrogen gas concentration R increases. Conversely, when the differential pressure X is reduced, the denominator is increased and the hydrogen gas concentration R is decreased.

  In this way, if a dilution gas resistor with flow rate limiting characteristics such that the intercept b value of the dilution gas flow curve is positive is selected and used, the hydrogen gas concentration in the mixed gas depends on the differential pressure X In addition, it becomes possible to control the hydrogen gas concentration to the reference value by adjusting the suction force.

  If the measured hydrogen gas concentration value is smaller than the set reference value, the suction force should be increased to increase the hydrogen gas concentration value, and the measured hydrogen gas concentration value should be set. If it is larger than the set reference value, the hydrogen gas concentration can be maintained at the set reference value by decreasing the suction force and decreasing the hydrogen gas concentration value.

Dilution gas flows through the dilution gas resistor due to the differential pressure generated at both ends of the dilution gas resistor, and hydrogen gas flows through the hydrogen gas resistor due to the differential pressure generated at both ends of the hydrogen gas resistor. It has been observed that when the dilution gas flows through the dilution gas resistor, the dilution gas has a property that the ratio of the change in the flow rate of the dilution gas to the change in the differential pressure decreases as the differential pressure increases. Therefore, the graph showing the relationship between the differential pressure and the dilution gas flow rate is convex upward when the differential pressure is taken on the horizontal axis.
The flow rate of the dilution gas flowing through the dilution gas resistor is set to be larger than the flow rate of the hydrogen gas flowing through the hydrogen gas resistor.

With reference to FIG. 1, the code | symbol 2 has shown the test gas production | generation apparatus of this invention.
The test gas generation apparatus 2 includes a hydrogen gas source 20 and a dilution gas source 21, and the hydrogen gas source 20 includes a bag-like container 28 made of a flexible resin. 28 is connected to a hydrogen gas inlet 25 which is one end of the hydrogen gas pipe 22.

  Here, no container is used as the dilution gas source 21, the atmospheric atmosphere is the dilution gas source 21, and the dilution gas inflow portion 26, which is one end of the dilution gas pipe 23, is in the atmospheric atmosphere as the dilution gas source 21. It is open to.

  The other end of the hydrogen gas pipe 22 and the other end of the dilution gas pipe 23 are connected to each other. If the connected portion is the joining portion 10, the hydrogen gas inflow portion 25 and the joining portion of the hydrogen gas piping 22 are joined. 10 is provided with a hydrogen gas resistor 32, and the hydrogen gas supplied from the hydrogen gas source 20 flows between the internal space of the hydrogen gas pipe 22 and the internal space of the hydrogen gas resistor 32. It flows through the constituted hydrogen gas flow path 12 and flows into the junction 10.

  Further, a dilution gas resistor 33 is provided between the dilution gas inflow portion 26 and the merge portion 10 of the dilution gas pipe 23, and the dilution gas supplied from the dilution gas source 21 is supplied to the dilution gas pipe 23. And the dilution gas flow path 13 constituted by the dilution gas resistor 33 and flows into the junction 10.

One end of a mixed gas pipe 24 is connected to the merging section 10, and the other end of the mixed gas pipe 24 is provided with a discharge portion 27 including a discharge port opened to the atmosphere.
In the junction 10, the flowing hydrogen gas and the dilution gas are mixed to generate a mixed gas.

  A suction pump 15 is provided between a portion of the mixed gas pipe 24 connected to the merging portion 10 and the discharge portion 27, and when the merging portion 10 is sucked by the suction pump 15, The mixed gas located at the position flows through the mixed gas flow path 14 constituted by the internal space of the mixed gas pipe 24 and the internal space of the suction pump 15 and is discharged from the discharge portion 27.

  An in-vehicle hydrogen sensor 37 to be inspected is disposed in the vicinity of the discharge unit 27, and the mixed gas discharged from the discharge unit 27 is blown to the in-vehicle hydrogen sensor 37, and the detection performance of the on-vehicle hydrogen sensor 37 for the mixed gas is detected. Can be tested.

  Here, the hydrogen gas resistor 32 has a flow restriction characteristic set in advance with respect to the hydrogen gas flowing through the hydrogen gas flow channel 12, and the dilution gas resistor 33 is connected to the dilution gas flow channel 13. Has a preset flow restriction characteristic for the dilution gas flowing through

  Of the mixed gas flow path 14 closer to the junction 10 than the hydrogen gas flow path 12, the dilution gas flow path 13, and the suction pump 15, the flow rate limiting effect of the portion other than the hydrogen gas resistor 32 and the dilution gas resistance 33. Is assumed to be negligibly small, the flow rate of the hydrogen gas flowing through the hydrogen gas flow path 12 is determined by the difference in pressure between both ends of the hydrogen gas resistor 32 and the flow rate limiting characteristic of the hydrogen gas resistor 32, Further, the flow rate of the dilution gas flowing through the dilution gas flow path 13 is determined by the pressure difference between both ends of the dilution gas resistor 33 and the flow rate limiting characteristic of the dilution gas resistor 33.

  The hydrogen gas source 20 is filled with high-concentration (here, 100%) hydrogen gas, the amount of hydrogen gas in the hydrogen gas source 20 is reduced, and the pressure in the flexible container is reduced. Atmospheric pressure presses the container, reducing the volume of the container, and the interior of the container is maintained at atmospheric pressure.

  In addition, when hydrogen gas is injected into the hydrogen gas source 20 from a hydrogen gas cylinder or the like and the pressure in the flexible container increases, the container expands against atmospheric pressure and the volume increases to increase the inside of the container. Is maintained at atmospheric pressure.

In the present invention, even when the suction force of the suction pump 15 is changed, the difference in pressure between both ends of the hydrogen gas resistor 32 and the difference in pressure between both ends of the dilution gas resistor 33 are made equal. .
In this example, one end of both ends of the hydrogen gas resistor 32 and the dilution gas resistor 33 is connected to the junction 10, and one end of the hydrogen gas resistor 32 and one end of the dilution gas resistor 33 are connected. Both are set to the pressure when the suction pump 15 operates and sucks the merging portion 10.

  The other ends of the hydrogen gas resistor 32 and the dilution gas resistor 33 are at atmospheric pressure. Therefore, the difference in pressure between both ends of the hydrogen gas resistor 32 and the pressure at both ends of the dilution gas resistor 33 are set. The difference is equal.

  When the suction pump 15 starts operating and the junction 10 is set to a pressure lower than the atmospheric pressure, hydrogen gas and dilution gas (air in the atmosphere here) are generated from the hydrogen gas source 20 and the dilution gas source 21. Each gas is supplied to the merge unit 10, and a mixed gas composed of the hydrogen gas and the dilution gas supplied from the merge unit 10 is generated, flows through the mixed gas channel 14, and is discharged from the discharge unit 27 to the atmosphere.

A hydrogen sensor 16 is provided in the mixed gas flow path 14 through which the mixed gas flows, and the hydrogen sensor 16 detects the hydrogen gas concentration of the mixed gas flowing through the mixed gas flow path 14.
Here, the mixed gas flowing through the mixed gas flow path 14 passes through the inside of the hydrogen sensor 16, but may be arranged so that the mixed gas does not pass through the hydrogen sensor 16.

  The hydrogen sensor 16 detects the hydrogen gas concentration of the mixed gas flowing through the mixed gas flow path 14 at a position between the suction pump 15 and the discharge portion 27 in the mixed gas flow path 14. Alternatively, the hydrogen gas concentration of the mixed gas flowing between the merging portion 10 and the merging portion 10 may be detected.

The hydrogen sensor 16 is connected to the control device 17, and a detection result indicating the detected hydrogen gas concentration is output from the hydrogen sensor 16 to the control device 17.
The control device 17 stores a reference value for the hydrogen gas concentration in advance.

  The hydrogen gas concentration of the mixed gas is changed by the differential pressure, and the control device 17 compares the input detection result with the reference value, and the hydrogen gas concentration detected by the hydrogen sensor 16 becomes equal to the reference value. As described above, when the suction force of the suction pump 15 is controlled and the hydrogen gas concentration of the mixed gas approaches the reference value, the hydrogen gas concentration of the mixed gas released from the discharge unit 27 becomes stable at the reference value, and the mixed gas is tested. When the in-vehicle hydrogen sensor 37 is operated while being blown to the in-vehicle hydrogen sensor 37 as a gas, it is possible to confirm whether the in-vehicle hydrogen sensor 37 is operating normally with respect to the test gas having the reference hydrogen gas concentration. it can.

Although the hydrogen gas charged in the hydrogen gas source 20 decreases, the volume of the flexible container 28 decreases, and the pressure in the container 28 is maintained at atmospheric pressure.
Since the generation of the test gas having a hydrogen gas concentration of 3.9% is required, the flow rate restriction characteristic for the hydrogen gas flow of the hydrogen gas resistor 32 and the flow restriction characteristic for the dilution gas flow of the dilution gas resistor 33 are The ratio of the flow rate of the dilution gas (air) to the flow rate of hydrogen gas is selected to be about 1: 24.6.

<Differential pressure and flow measurement>
The flow rate measurement with respect to the differential pressure between the hydrogen gas resistor 32 and the dilution gas resistor 33 was performed by the apparatus shown in FIGS.

  The difference in pressure between both ends of the hydrogen gas resistor 32 was measured by a differential pressure gauge 31, and the flow rate of the hydrogen gas flowing through the hydrogen gas resistor 32 was measured by using a flow meter 41 (a soap film type). The measurement of the difference in pressure at both ends of the dilution gas resistor 33 and the flow rate of the dilution gas flowing through the dilution gas resistor 33 were performed in the same manner.

  Assuming that the pressure difference between both ends of the hydrogen gas resistor 32 and the pressure difference between both ends of the dilution gas resistor 33 is a differential pressure, the measurement result, the differential pressure calculated from the measurement result, and the mixed gas The relationship with the hydrogen gas concentration is shown in Table 1 below.

  FIG. 2 is a graph connecting the measured values of the flow rate of hydrogen gas with respect to the differential pressure of the resistor 32 for hydrogen gas in Table 1, and FIG. 3 shows the flow rate of dilution gas with respect to the differential pressure of the resistor 33 for diluent gas. It is the graph which connected the measured value. FIG. 4 is a graph connecting the calculated values of the hydrogen gas concentration of the mixed gas with respect to the differential pressure in Table 1.

Next, a differential pressure gauge 31 is connected to the merging portion 10 of the test gas generating device 2 and mixing is performed by controlling the suction pump 15 by the control device 17 so that the differential pressure is the same as the differential pressure described in Table 1. Gas was prepared and the hydrogen gas concentration was detected by the hydrogen sensor 16.
The detected hydrogen gas concentration is shown in Table 2 below together with the calculated hydrogen gas concentration.

The relationship between the hydrogen gas concentration with respect to the pressure measurement result of the differential pressure gauge 31 in Table 2 and the relationship with the hydrogen gas concentration obtained by calculation with respect to the differential pressure are shown as graphs in FIG.
The difference between the calculated value and the actually measured value is based on the individual flow rate measured value with respect to the pressure difference between the both ends of the hydrogen gas resistor 32 and the dilution gas resistor 33, whereas the actually measured value shows the flow meter 41. This is considered to be based on the result of actual measurement of the hydrogen gas concentration by the hydrogen sensor 16 without inserting (soap type). The soap film type flow meter is suitable for measuring a micro flow rate with a small pressure loss, but the micro flow rate is affected by the surface tension and gravity of the soap film, and the hydrogen gas concentration and flow meter obtained from the flow rate ratio It appears as a difference from the measured value of the hydrogen gas concentration without insertion of.
Both characteristics of the calculated value and the actually measured value indicate that the hydrogen gas concentration can be adjusted by controlling the differential pressure or controlling the pressure at the junction.

<Measurement device>
The measuring apparatus which calculated | required the numerical value of Table 1, 2 is demonstrated.
In order to obtain the relationship between the differential pressure and the hydrogen gas flow rate for the hydrogen gas resistor 32, a flexible container 28 is connected to the hydrogen gas inlet 25 as shown in FIG. Is connected to one end of the hydrogen gas resistor 32 via the flow meter 41, and the other end is connected to the suction pump 15.

  The suction pump 15 is operated to suck 100% hydrogen gas stored in the container 28, pass through the hydrogen gas resistor 32 while measuring the flow rate with the flow meter 41, and release it from the discharge unit 27 to the atmosphere. .

  A differential pressure gauge 31 is connected in parallel with the hydrogen gas resistor 32, and when the hydrogen gas flows through the hydrogen gas resistor 32, the differential pressure generated at both ends of the hydrogen gas resistor 32 is measured. The relationship between the differential pressure and the hydrogen gas flow rate for the hydrogen gas resistor 32 is obtained by changing the suction force of the suction pump 15 and measuring the differential pressure and the hydrogen gas flow rate of the hydrogen gas resistor 32. Can do.

Further, in order to obtain the relationship between the differential pressure and the dilution gas flow rate for the dilution gas and the dilution gas resistor 33, as shown in FIG. 8, the dilution gas inlet 26 opened to the atmosphere is connected to the flow meter 41. The other end of the dilution gas resistor 33 is connected to the suction pump 15.
The suction pump 15 is operated to suck air from the dilution gas inflow portion 26 as dilution gas, pass through the dilution gas resistor 33 while measuring the flow rate with the flow meter 41, and release the air from the discharge portion 27 to the atmosphere.

  Similar to the measurement of the hydrogen gas resistor 32, the differential pressure gauge 31 is connected in parallel with the dilution gas resistor 33, and when the dilution gas flows through the dilution gas resistor 33, the dilution gas resistance The differential pressure generated at both ends of the body 33 is measured. The relationship between the differential pressure and the dilution gas flow rate for the dilution gas resistor 33 is obtained by changing the suction force of the suction pump 15 and measuring the differential pressure and the dilution gas flow rate of the dilution gas resistor 33. Can do.

<Detection result of hydrogen gas concentration>
Next, a hydrogen gas concentration of 3.9% was set as a reference value in the control device 17 of the test gas generation device 2 to generate a mixed gas, which was discharged from the discharge portion 27 as a test gas. The hydrogen gas concentration of the generated mixed gas was detected by the hydrogen sensor 16. The transition of the hydrogen concentration as a detection result is shown in the graph of FIG.

  About 8 seconds after the suction pump 15 started operating, the detection result became the same hydrogen gas concentration as the reference value. The hydrogen concentration returned to zero after about 15 seconds, indicating a response when the supply of hydrogen gas was stopped by disconnecting the container 28 from the hydrogen gas inflow portion 25 in order to confirm the fall of the detection result. Yes.

<Resistor, gas source>
As the hydrogen gas resistor 32, an injection needle-like stainless steel tube having an inner diameter of 0.35 mm and a length of 37 mm was used. As the dilution gas resistor 33, a resin tube having an inner diameter of 1.0 mm and a length of 30 mm was used.
In addition to the capillary tube, a pinhole or a porous body can be used for the hydrogen gas resistor 32 and the dilution gas resistor 33.

  As described above, one end of the hydrogen gas resistor 32 and one end of the dilution gas resistor 33 are set to the atmospheric pressure, and the other end is set to the same pressure at the merging portion 10, but one end opposite to the merging portion 10 is However, the pressure is not limited to the case where the same pressure is maintained. If a constant pressure is maintained, one end of the hydrogen gas resistor 32 and one end of the dilution gas resistor 33 may be at different pressures. Good.

  As for the hydrogen gas source, for example, as in the hydrogen gas source 20a shown in FIG. 9A, a metal container 42 in which a hydrogen storage alloy is arranged is used, and the hydrogen storage alloy is made to store hydrogen gas, A hydrogen gas outlet of the metal container 42 is connected to the hydrogen gas inflow portion 25, and a flexible container 43 is connected to a hydrogen gas flow path between the metal container 42 and the hydrogen gas inflow portion 25. At this time, the amount (specification) of the hydrogen storage alloy so that the flow rate of the hydrogen gas released from the hydrogen storage alloy inside the metal container 42 is slightly larger than the flow rate of the hydrogen gas that should flow to the hydrogen gas resistor 32. Must be properly selected. The excess hydrogen at this time moves to the flexible container 43, whereby the pressure in the hydrogen gas inflow portion 25 can be maintained at atmospheric pressure.

  Further, as in the hydrogen gas source 20b shown in FIG. 9B, the pressure of the hydrogen gas flow path between the hydrogen gas outlet of the metal container 42 containing the hydrogen storage alloy and the hydrogen gas inflow portion 25 is released to the atmosphere. An open portion 45 may be provided to release excess hydrogen gas to the atmosphere, and hydrogen gas may be supplied so that one end of the hydrogen gas resistor 32 is maintained at atmospheric pressure.

  In addition to 100% hydrogen gas, hydrogen gas diluted with dilution gas can be used for the hydrogen gas source 20, but when the hydrogen concentration of the hydrogen gas source 20 changes, the relationship between the differential pressure and the flow rate. Therefore, it is necessary to reselect the flow restricting characteristics of the hydrogen gas resistor 32 and the dilution gas resistor 33.

2 ... Test gas generator 12 ... Hydrogen gas flow path 13 ... Dilution gas flow path 14 ... Mixed gas flow path 15 ... Suction pump 16 ... Hydrogen sensor 17 ... Control devices 20, 20a, 20b ... Hydrogen gas source 21 ... Dilution gas source 28 ... Container 32 ... Hydrogen gas resistor 33 ... Dilution gas resistor

Claims (4)

A hydrogen gas flow path through which hydrogen gas supplied by a hydrogen gas source passes,
A dilution gas flow path through which the dilution gas supplied by the dilution gas source passes,
A merge portion where the hydrogen gas flow path and the dilution gas flow path merge;
The hydrogen gas flowing in from the hydrogen gas flow path and the dilution gas flowing in from the dilution gas flow path are contained, and the mixed gas generated in the merging portion is sucked with suction force and supplied to the output portion A suction pump;
A hydrogen gas resistor that is provided in the hydrogen gas flow path and restricts the flow of the hydrogen gas through the hydrogen gas flow path;
A dilution gas resistor that is provided in the dilution gas flow path and restricts the flow of the dilution gas through the dilution gas flow path;
A hydrogen sensor for detecting the hydrogen gas concentration of the mixed gas;
A control device for changing the suction force of the suction pump;
Have
Air is used as the dilution gas,
Due to the differential pressure generated at both ends of the dilution gas resistor, the dilution gas flows into the dilution gas resistor, and due to the differential pressure generated at both ends of the hydrogen gas resistor, The hydrogen gas is configured to flow,
The inclination of the dilution gas flow curve showing the relationship between the dilution gas flow rate through the differential pressure and the diluent gas generating resistor at both ends of said diluent gas generating resistor, both ends of the differential pressure and the hydrogen of the hydrogen gas generating resistor The slope of the hydrogen gas flow curve indicating the relationship between the hydrogen gas flow rates flowing through the gas resistor is a different numerical value, and the tangent line on the dilution gas flow curve is a coordinate system of the differential pressure and the dilution gas flow curve The dilution gas resistor such that the intercept with the flow axis of the coordinate system is a positive value without passing through the origin at
A detection result detected by the hydrogen sensor is input to the control device,
The control device is a test gas generation device that changes the suction force of the suction pump so that the hydrogen gas concentration becomes a reference value.   The test gas generation device according to claim 1, wherein the hydrogen sensor detects a hydrogen gas concentration of the mixed gas supplied to the output unit by the suction pump. 3. The test gas generation device according to claim 1, wherein pressures of the dilution gas supplied from the dilution gas source and the hydrogen gas supplied from the hydrogen gas source are set to atmospheric pressure. 4.   The suction pump sucks the mixed gas with the suction force that makes the differential pressure at both ends of the hydrogen gas resistor and the differential pressure at both ends of the dilution gas resistor at 400 Pa or more. The test gas generation device according to any one of claims 1 to 3, wherein the test gas generation device is configured.

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