JP2006156320A - Stopping method of gas consumption apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stopping method of a gas consumption apparatus capable of improving the sealing performance of a cutoff valve. <P>SOLUTION: A tank 11 with hydrogen stored therein is connected to a fuel cell 1 as a gas consumption apparatus through gas piping 10. In the gas piping 10, a primary cutoff valve 13 for cutting off the circulation of hydrogen is mounted. The fuel cell 1 is mounted on a fuel cell electric vehicle, and when an off-signal of an ignition switch for stopping the power generation of the fuel cell is inputted to a control device 40 from the vehicle side, the control device 40 closes the primary cutoff valve 13. Then, hydrogen on the downstream side of the primary cutoff valve 13 is consumed by continuing the power generation of the fuel cell 1, and a pressure difference is generated between the primary side and the secondary side of the primary cutoff valve 13. When the pressure difference is generated, a load 50 is disconnected and the power generation is stopped. Thus, the pressure difference is generated between the primary side and the secondary side of the primary cutoff valve 13 in the power generation stop, whereby the sealing performance of the primary cutoff valve 13 is improved by the pressure difference. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for stopping a gas consuming device, and more particularly to a method for stopping a gas consuming device in which a shutoff valve is provided in a gas pipe for supplying fuel gas to the gas consuming device.

For example, a fuel cell is known as a gas consuming device. A hydrogen tank and an air compressor are connected to an anode electrode and a cathode electrode of the fuel cell via gas pipes, respectively, and the fuel cell generates power by an electrochemical reaction when supplied with hydrogen and oxygen. In order to increase the storage efficiency, hydrogen is usually stored in a hydrogen tank in a pressurized state, from which hydrogen is supplied at a high pressure. For this reason, the gas pipe is provided with a pressure reducing valve, and hydrogen decompressed to a predetermined pressure is supplied. As such a gas supply device, for example, a technique disclosed in Patent Document 1 is known.
This is a method of stopping and restarting the gas consuming equipment when the pressurized fuel gas is supplied to the downstream side without being fully decompressed when the valve pressure reducing valve provided in the gas pipe fails. This is a technique for avoiding an abnormal stop by providing shut-off valves upstream and downstream of the pressure reducing valve in the piping and opening the shut-off valve on the downstream side before the shut-off valve on the upstream side.
JP 2004-1000058 A (claims)

There are various uses for fuel cells. For example, when it is mounted on an electric vehicle and used as a fuel cell electric vehicle, it can be used in a low temperature environment. However, when a shut-off valve is provided in the gas pipe as in the prior art, the sealing characteristics of the shut-off valve under a low-temperature inertial environment cannot be expected. For this reason, when a fuel cell electric vehicle is used in a low-temperature environment. As a result, the sealing performance of the shut-off valve and the like deteriorated, and hydrogen leaked downstream.
An object of the present invention is to provide a method for stopping a gas consuming device capable of improving the sealing performance of a shut-off valve and suppressing the leakage of fuel gas even in a low temperature environment in view of the conventional problems.

Therefore, the invention according to claim 1 is a method for stopping a gas consuming device, wherein a gas pipe for supplying fuel gas to the gas consuming device is connected, and the fuel gas is shut off from the gas pipe. When shutting down the gas consuming device, the shutoff valve is closed, and the gas pipe until the pressure difference between the upstream and downstream of the shutoff valve in the gas pipe reaches a predetermined value. After the fuel gas inside was consumed, the gas consuming device was stopped.
Thus, when the gas consuming device is stopped, a pressure difference of a predetermined value or more can be generated upstream and downstream of the shutoff valve.

According to the second aspect of the present invention, the consumption time for consuming fuel gas in the gas pipe until the pressure difference between the upstream side and the downstream side of the cutoff valve reaches a predetermined value with the cutoff valve closed. A predetermined time is set in advance, and after closing the shut-off valve, the fuel gas in the gas pipe is consumed for the set predetermined time, and then the gas consuming device is stopped.
Thereby, after closing the shut-off valve, the gas consuming device can be stopped only by checking the passage of time.

According to a third aspect of the present invention, a pressure reducing valve for reducing the pressure of the fuel gas is disposed downstream of the shutoff valve in the gas pipe, and the predetermined time is set according to a control pressure of the pressure reducing valve. It was assumed.
Accordingly, the gas consuming device can be stopped in the shortest time according to the control pressure when the pressure reducing valve is operated.

According to a fourth aspect of the present invention, the gas consuming device is a fuel cell, and after the shut-off valve is closed, the fuel gas reacts with oxygen or moisture in the fuel cell is removed. For this reason, the fuel gas in the gas pipe is consumed by purging.
Thereby, even when the gas consuming device is a fuel cell, a pressure difference of a predetermined value or more can be generated upstream and downstream of the shutoff valve.

  According to the present invention, when a gas consuming device such as a fuel cell is stopped, a pressure difference of a predetermined value or more is generated upstream and downstream of the shutoff valve, and as a result, the shutoff valve in the shutoff valve that shuts off the flow of fuel gas is generated. The force acting on the valve body can be strengthened and the sealing performance of the shutoff valve can be improved. Therefore, even if the sealing performance is lowered due to the low temperature, the fuel gas is effectively prevented from leaking downstream from the shutoff valve while the gas consuming device is stopped.

Hereinafter, the gas consuming apparatus will be described using a fuel cell mounted on a fuel cell electric vehicle. FIG. 1 is a diagram showing a configuration of a fuel cell system mounted on a fuel cell electric vehicle.
A tank 11 is connected to the inlet of the anode electrode of the fuel cell 1 through a gas pipe 10. In the gas pipe 10, a tank shutoff valve 12, a primary shutoff valve 13, a primary pressure reducing valve 14, a relief valve 15, a secondary shutoff valve 16, a secondary pressure reducing valve 17, and an ejector 18 are sequentially provided from the tank 11. It is done.

The tank 11 stores high pressure hydrogen of about 35 MPa. During power generation, hydrogen is supplied from the tank 11, and the supplied hydrogen is primarily depressurized by the primary pressure-reducing valve 14 and secondarily depressurized by the secondary pressure-reducing valve 17 to become a predetermined pressure, so that the anode electrode of the fuel cell 1 is provided. To be supplied. The set pressure of the primary pressure reducing valve 14 is 1 MPa, and the set pressure of the secondary pressure reducing valve 17 is 0.5 MPa.
Accordingly, the gas pipe 10 is divided into lines having different pressures, with the primary pressure reducing valve 14 and the secondary pressure reducing valve 17 as a boundary. The upstream side of the primary pressure reducing valve 14 is a high pressure line 10a for generating a high pressure of about 35 MPa at maximum, and the intermediate pressure line 10b for generating a medium pressure of 1 MPa is generated between the primary pressure reducing valve 14 and the secondary pressure reducing valve 17; Between the secondary pressure reducing valve 17 and the fuel cell 1 is a low pressure line 10c in which a low pressure of 0.5 MPa or less is generated.

In the gas pipe 10, the primary shut-off valve 13 is positioned in the high pressure line 10a, and a first pressure sensor 21 for detecting the pressure on the primary side and a second pressure sensor 22 for detecting the pressure on the secondary side are provided on both sides thereof. It has been.
The relief valve 15 is located in the intermediate pressure line 10b, and its operating pressure is set higher than 1 MPa, which is the specification pressure of the intermediate pressure line 10b. Therefore, when a pressure higher than the specified pressure is generated in the intermediate pressure line 10b, the relief valve 15 is opened, so that hydrogen is released and the pressure in the intermediate pressure line 10b can be lowered. The relief valve 15 is provided with an intermediate pressure sensor 23 for detecting the pressure in the intermediate pressure line 10b.

The ejector 18 is located in the low-pressure line 10c, and one end thereof is connected to the circulation gas pipe 20 connected to the outlet of the anode electrode so as to return the unreacted gas discharged from the anode electrode. The gas pipe 20 is provided with a purge valve 19 for discharging generated water generated in the fuel cell 1.
The gas pipes 10 and 20 and the related parts from the tank 11 to the anode electrode of the fuel cell 1 are configured as described above, but a gas pipe and an air compressor (not shown) are connected to the cathode electrode side of the fuel cell 1, Air can be supplied to the cathode electrode of the fuel cell 1. In the fuel cell 1, electric power is generated by causing an electrochemical reaction between hydrogen supplied to the anode electrode and oxygen in the air supplied to the cathode electrode.

  The load 50 connected to the fuel cell 1 includes an auxiliary machine such as an air compressor other than the traveling motor. Further, the load 50, the primary cutoff valve 13, the secondary cutoff valve 16, the purge valve 19, the first pressure sensor 21, the second pressure sensor 22, and the intermediate pressure sensor 23 are connected to the control device 40. The control device 40 receives an ignition switch signal from the vehicle side in order to control the fuel cell 1.

2A and 2B are diagrams showing the configuration of the primary shut-off valve. FIG. 2A is a cross-sectional view, and FIG. 2B is an enlarged view of a portion A in FIG.
The primary shut-off valve 13 is a valve driven by electromagnetic force, and a plunger 32 is provided at the center of a cylindrical coil 31. The primary shut-off valve 13 is a so-called kick pilot type solenoid valve, and can be opened with a relatively small electromagnetic force even when the pressure difference between the primary side and the secondary side is large. For this reason, when the pressure difference is large due to the relationship between the pressure difference between the primary side and the secondary side, the primary shut-off valve 13 does not open at once due to the electromagnetic force of the coil 31, and in two stages. The valve is configured to open. Hereinafter, the configuration and operation of the primary cutoff valve 13 will be described.

  The plunger 32 is urged downward by a spring 35. The plunger 32 is provided with a plunger hole (support hole) 32a in which the upper part of the valve body 33 is inserted in the lower part. A step 32b is provided below the plunger hole 32a. When the plunger 32 moves upward, the lower portion 33b of the valve body 33 and the upper portion of the step 32b are engaged with each other. . The distance between the upper portion (top surface) of the plunger hole 32a and the upper portion of the step portion 32b is smaller than the moving distance in which the plunger 32 moves up and down by the electromagnetic force of the coil 31 in order to realize the above-described two-stage valve opening. Is set.

The valve body 33 includes a large-diameter portion 33 a and a small-diameter portion 33 b that are vertically spaced apart from each other. The large-diameter portion 33 a is slidably supported by the valve hole 30, and the small-diameter portion 33 b is formed at the lower end of the plunger 32. The plunger hole 32a is slidably supported. The large-diameter portion 33a and the small-diameter portion 33b are provided with passages 33d and 33e, respectively, and communicate the primary side piping port with the upper portion of the plunger hole 32a. Further, the valve element 33 functions as a first-stage valve opening when the pressure difference between the primary side and the secondary side is large, and communicates the primary side (upper part of the plunger hole 32a) and the secondary side. A small-diameter through hole 33c is provided. When the valve is closed, the through-hole 33c is closed by a seal 32c provided at the lower portion of the plunger 32 to block the primary side and the secondary side. The valve seat 30A of the primary shutoff valve 13 is provided with a secondary side communication hole 30a communicating with the secondary side. The diameter of the secondary side communication hole 30a is larger than the diameter of the through hole 33c. It has a large diameter.
A ring-shaped sheet 34 is provided on the lower end surface of the large-diameter portion 33a. On the other hand, the valve seat 30A is provided with a ring-shaped protrusion that surrounds the outer periphery of the secondary side communication hole 30a with a predetermined distance. Sealing is performed by the seat 34 and the protrusion of the valve seat 30A, and the primary side and the secondary side are blocked.

(Opening the primary shut-off valve)
Since the primary shut-off valve 13 is configured as described above, when the coil 31 is energized with a pressure difference between the primary side and the secondary side, the plunger 32 is first pulled up by electromagnetic force. At this time, when a high pressure is applied to the primary side, the force due to the differential pressure applied to the portion of the through hole 33c tries to prevent the plunger 32 from moving upward. However, since the hole diameter of the through hole 33c is smaller than the hole diameter of the secondary side communication hole 30a, the force due to the differential pressure (force that prevents the plunger 32 from moving upward) is electromagnetic force (the plunger 32 is moved upward). The plunger 32 moves upward with a force smaller than the force to be moved. As a result, the gas on the primary side gradually starts to flow into the secondary side through the narrow passage of the through hole 33c (first stage valve opening).

  Next, the plunger 32 moves further upward, but the lower portion of the small diameter portion 33b and the upper portion of the step portion 32b are engaged with each other. The coil 31 tries to move the valve body 33 upward together with the plunger 32 by the generated electromagnetic force (although it tries to lift it), but the valve body 33 has a secondary side having a diameter larger than the diameter of the through hole 33c. Since the force of a large differential pressure due to the communication hole 30a (the inner diameter of the seat 34) is acting, the upward movement of the plunger 32 is stopped.

  While the upward movement of the plunger 32 is stopped, gas flows from the primary side to the secondary side through the narrow communication hole 33c, and the differential pressure between the primary side and the secondary side is gradually reduced. It has become. Eventually, when the force of the differential pressure becomes smaller than the electromagnetic force, the valve element 33 slides on the valve hole 30 and is pulled upward by the plunger 32. As a result, the primary shut-off valve 13 is completely opened, and the primary side and the secondary side are brought into communication with each other, so that the valve is completely opened (second stage valve opening).

(Primary shut-off valve closed)
When the energization of the coil 31 is interrupted, the plunger 32 is lowered (moves downward) by the urging force of the spring 35, the valve element 33 is pressed against the valve seat 30A, and the primary side and the secondary side are deformed by the deformation of the seat 34. Communication on the side is interrupted. At this time, the through hole 33c of the small diameter portion 33b is also closed by the seal 32c provided on the end face of the support hole 32a of the plunger 32, and the primary shutoff valve 13 is closed.
As described above, when the primary shut-off valve 13 is closed, the valve element 33 is pressed against the valve seat 30A by the biasing force of the spring 35. However, the seat 34 is degenerated at a low temperature due to the modification of the seat 34 and the biasing force of the spring 35. 34 may not be sufficiently deformed, and as a result, hydrogen gas may leak to the secondary side.

Incidentally, if the urging force of the spring 35 is increased, the sealing performance by the seat 34 is improved, but a large electromagnetic force is required when the valve is opened, which is not preferable because power consumption by the coil 31 is increased.
Here, if a pressure difference is generated between the primary side and the secondary side, in addition to the urging force of the spring 35, the force for pressing the valve element 33 can be increased by the pressure difference. Thereby, an improvement in sealing performance can be realized.

Next, the control flow when the fuel cell 1 stops generating power in the control device 40 will be described.
FIG. 3 is a flowchart showing the flow of control when power generation is stopped. This flowchart is executed when the ignition switch OFF signal is input from the vehicle side.
When an ignition switch-off signal is input from the vehicle side, a valve closing signal is output to the primary shut-off valve 13 to close the valve in step S1.
In step S <b> 2, the primary pressure P <b> 1 detected by the first pressure sensor 21 is input.
In step S3, it is determined whether or not the pressure in the tank 11 is 5 MPa or more based on the primary pressure P1. In the case of the above, the process proceeds to step S4, where the secondary pressure P2 detected by the second pressure sensor 22 on the secondary side is input.

In step S5, the load 50 is controlled to generate power in the fuel cell 1 in, for example, an eye drink state. As a result, the hydrogen gas on the downstream side (secondary side) of the primary cutoff valve 13 is consumed, and the pressure on the downstream side gradually decreases.
In step S6, a pressure difference between the primary pressure P1 and the secondary pressure P2 is calculated, and it is determined whether the pressure difference is greater than 5 MPa.
When the pressure difference is 5 MPa or less, it is assumed that a sufficient pressure difference is not formed between the primary side and the secondary side of the primary cutoff valve 13, and the process returns to step S5 to continue power generation.
If it is determined in step S6 that the pressure difference is larger than 5 MPa, it is assumed that a sufficient pressure difference is formed between the primary side and the secondary side of the primary shut-off valve 13, and the process proceeds to step S7.
In step S7, the secondary shutoff valve 16 on the downstream side is closed. In step S8, the load 50 is disconnected from the fuel cell 1 to stop power generation. When power generation is stopped, the cathode air compressor is also stopped.

  As described above, when the ignition switch OFF signal is input, the control device 40 controls the load 50 and continues the power generation of the fuel cell 1 with the primary shut-off valve 13 closed. A pressure difference of 5 MPa or more can be generated between the primary side and the secondary side of the primary cutoff valve 13. Therefore, in the primary shut-off valve 13, in addition to the urging force of the spring 35 (see FIG. 2), the pressure formed by the pressure difference is further applied to the valve body 33, and the valve body 33 is applied to the end face of the valve hole 30. The pressing force can be strengthened. As a result, the sealing performance can be improved even in a low temperature environment where the sheet 34 is likely to leak.

FIG. 4 is a diagram showing a test result regarding sealability when the method for stopping a gas consuming device according to the present invention is used.
FIG. 5 is a diagram showing a test result relating to the sealing performance when the fuel cell is stopped at the same time as the conventional valve closing operation.
Note that the test was performed at a minus 40 degree, which is likely to cause hydrogen to leak by a normal stopping method. In order to easily observe the leak, the tank cutoff valve 12 was also closed so that hydrogen was not replenished from the tank 11 when the primary cutoff valve 13 was closed. 4 and 5 show the primary-side pressure P1 and the secondary-side pressure P2 that start after the fuel cell 1 stops generating power.

  According to FIG. 4, after the power generation of the fuel cell 1 is stopped, hydrogen leaks due to leakage of the primary pressure reducing valve 14 etc. on the downstream side, and the pressure P2 on the secondary side decreases with time. On the other hand, the pressure P1 on the primary side is maintained at a substantially constant value. That is, it is recognized that there is no hydrogen leak from the primary side to the secondary side. This is because when the power generation of the fuel cell 1 is stopped, a pressure difference of 5 MPa is generated between the primary side and the secondary side of the primary shut-off valve 13, so that the valve body 33 is strongly connected to the valve hole 30 (see FIG. 2). It is considered that the sheet 34 is sufficiently deformed to achieve high sealing performance even in a low temperature environment.

  On the other hand, in FIG. 5 using the conventional stopping method, the primary side pressure P1 similarly decreases as the secondary side pressure P2 decreases due to the leakage of the primary pressure reducing valve 14 or the like. Is recognized as occurring. And even if the pressure P2 on the secondary side is lowered, the pressure P1 on the primary side is also lowered, so that a large pressure difference is not generated over time, so that the sealing performance is not improved while power generation is stopped.

Next, a second embodiment will be described.
In the first embodiment, the fuel cell 1 continues to generate power even after the primary shut-off valve 13 is closed to generate a pressure difference between the primary side and the secondary side of the primary shut-off valve 13. When a predetermined pressure difference is generated, power generation of the fuel cell 1 is stopped. The detection of the pressure difference is performed by the primary pressure sensor 21 on the primary side and the secondary pressure sensor 22 on the secondary side of the primary shut-off valve 13, but in the second embodiment, the pressure sensor is used. I try to leave out. That is, in the second embodiment, the first pressure sensor 21 and the second pressure sensor 22 are omitted from the configuration shown in FIG. 1, and the stop timing of the fuel cell 1 is estimated by estimating the pressure difference. Stop.

  In a fuel cell, the amount of hydrogen consumed can be determined from the generated current. Therefore, when the primary cutoff valve 13 is closed, the amount of pressure drop on the secondary side of the primary cutoff valve 13 can be obtained by measuring the generated current and the power generation time of the fuel cell 1. By the way, since the primary pressure reducing valve 14 is provided on the secondary side, a time difference is caused by the control pressure of the primary pressure reducing valve 14.

FIG. 6 shows characteristics of control pressure and flow rate in the pressure reducing valve.
This indicates that the control valve has different control pressure characteristics when the flow rate is increased and when the flow rate is decreased. As a characteristic of the pressure reducing valve, the control pressure has an m value when the flow rate on the downstream side increases, and once it is controlled to the n value when the flow rate decreases, it gradually approaches the m value. The valve of the pressure reducing valve is open when the control pressure is the m value, and is closed during the transition from the n value and the n value to the m value (A1 shown in FIG. 6).
By utilizing this, when the control pressure of the pressure reducing valve is at m value, since the pressure reducing valve is open, hydrogen on the primary side tends to flow out to the secondary side. The time is set to a relatively short time (for example, 1 second). In addition, when the control pressure of the pressure reducing valve is higher than the m value or when shifting from the n value to the m value, since the pressure reducing valve is closed, the pressure reducing valve is opened and the secondary side is opened. Since the valve opening time until it flows out is required, it is set to a longer time (for example, 20 seconds) than when the control pressure is the m value.

  Whether the pressure reducing valve is at the n value or the m value can be determined by measuring the control pressure, but there are many other methods. For example, when the pressure on the upstream side is detected and the pressure falls without delay, it can be determined that the pressure reducing valve is moving from the m value or the n value to the m value, and the upstream pressure is maintained. When it is determined, it can be determined that the pressure reducing valve 14 is moving from the n value to the m value. Therefore, if different power generation times are set when the pressure reducing valve has an m value and at other times, the predetermined pressure difference is generated by applying the different time by detecting the control pressure of the pressure reducing valve, and the shortest Power generation can be stopped in the time.

Next, a control flow when the fuel cell 1 stops generating power in the control device 40a will be described.
FIG. 7 is a flowchart showing a control flow when power generation is stopped in the second embodiment. This flowchart is also executed when the ignition switch OFF signal is input.
When the ignition switch OFF signal is input from the vehicle side, a valve closing signal is output to the primary shutoff valve 13 in step S11 to close the valve.
In step S12, the control pressure of the primary pressure reducing valve 14 is determined using the method described above. As a result of the control pressure determination, when the control pressure of the primary pressure reducing valve 14 is m value, the process proceeds to step S13 and the fuel cell is caused to generate power.

  In step S14, it is determined whether 1 second has elapsed since the primary shut-off valve 13 was closed or whether the pressure of the intermediate pressure line 10b became 700 KPa or less based on the detected value of the intermediate pressure sensor 23. If either of them is satisfied, the process proceeds to step S15, and the secondary shutoff valve 16 is closed. Subsequently, in step S16, the load 50 is disconnected and power generation is stopped. If both are not satisfied, the process returns to step S13 to continue power generation.

If it is determined in step 12 that the control pressure is higher than the m value, the fuel cell is caused to generate power in step S17.
In step S18, it is determined whether 20 seconds have passed since the primary shut-off valve 13 was closed or whether the pressure of the intermediate pressure line 10b became 700 KPa or less based on the detected value of the intermediate pressure sensor 23. If either of them is satisfied, the process proceeds to step S19, the secondary shutoff valve 16 is closed, and the load 50 is disconnected in the subsequent step S16 to stop power generation. If both are not satisfied, the process returns to step S17 to continue power generation.

  Also according to the second embodiment, when an ignition switch-off signal is input as in the first embodiment, the control device 40a causes the load 50 to remain in the state where the primary shut-off valve 13 is closed. Since the power generation of the fuel cell 1 is continued under the control, a pressure difference of 5 MPa or more can be generated between the primary side (upstream side) and the secondary side (downstream side) of the primary cutoff valve 13. Therefore, in the primary shut-off valve 13, when the primary shut-off valve 13 is closed, in addition to the biasing force of the spring 35, the pressure formed by the pressure difference is further applied to the valve body 33, and the valve body 33 Can be pressed against the end face of the valve hole 30, and the sealing performance can be improved even in a low temperature environment where leakage is likely to occur.

Further, in the second embodiment, the pressure sensor for detecting the primary side pressure and the secondary side pressure of the primary shut-off valve 13 can be omitted, and therefore, compared with the first embodiment, The effect which can be comprised at low cost is acquired simultaneously.
In each of the embodiments described above, the consumption of hydrogen is performed by generating power in the fuel cell 1, but it is not necessary to generate power. For example, the purge valve 19 is opened to remove moisture in the fuel cell. For this purpose, the hydrogen in the gas pipe can be discharged and consumed.

  In the present embodiment, the fuel cell has been described as the gas consuming device. However, it is needless to say that the present invention can be applied not only to the fuel cell but also to an engine vehicle using fuel gas as fuel. Further, in the embodiment, the improvement in the sealing performance of the primary cutoff valve 13 has been described, but the present invention can also be applied to the tank cutoff valve 12 and the secondary cutoff valve 16. Of course, each shut-off valve can be applied alone or jointly.

  It is a figure which shows the structure of the fuel cell system mounted in a fuel cell electric vehicle.   It is a figure which shows the structure of a primary cutoff valve.   It is a flowchart which shows the flow of control at the time of a power generation stop.   It is a figure which shows the test result regarding the sealing performance at the time of utilizing the stop method which concerns on this invention.   It is a figure which shows the test result regarding the sealing performance when the power generation of the fuel cell is stopped simultaneously with the valve closing.   It is a figure which shows the pressure characteristic of a pressure-reduction valve.   It is a flowchart which shows the flow of control at the time of the electric power generation stop in 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 10 Gas piping 10a High pressure line 10b Medium pressure line 10c Low pressure line 11 Tank 12 Tank shutoff valve 13 Primary shutoff valve 14 Primary decompression valve 15 Relief valve 16 Secondary shutoff valve 17 Secondary decompression valve 18 Ejector 19 Purge valve 20 Gas piping 21 First pressure sensor 22 Second pressure sensor 23 Medium pressure sensor 30 Valve hole 31 Coil 32 Plunger 32a Support hole 33 Valve body 33a Large diameter portion 33b Small diameter portion 33c Through hole 34 Seat 35 Spring 40, 40a Control device 50 load

Claims (4)

A method for stopping gas consuming equipment,
A gas pipe for supplying fuel gas to the gas consuming device is connected, and the gas pipe is provided with a shut-off valve for blocking the flow of the fuel gas,
When stopping the gas consuming equipment,
Closing the shutoff valve;
The gas consuming device is characterized in that the gas consuming device is stopped after consuming the fuel gas in the gas piping until the pressure difference between the upstream and downstream of the shutoff valve in the gas piping reaches a predetermined value. How to stop. With the shut-off valve closed, a consumption time for consuming fuel gas in the gas pipe is set as a predetermined time in advance until the pressure difference between the upstream and downstream of the shut-off valve reaches a predetermined value.
The gas consuming device according to claim 1, wherein after the shut-off valve is closed, the gas consuming device is stopped after the fuel gas in the gas pipe is consumed for the set predetermined time. How to stop.   The pressure reducing valve for reducing the pressure of the fuel gas is disposed downstream of the shutoff valve in the gas pipe, and the predetermined time is set according to the control pressure of the pressure reducing valve. Stop method of gas consumption equipment as described in 4. The gas consuming device is a fuel cell,
After the shut-off valve is closed, the fuel gas in the gas pipe is consumed by reacting the fuel gas with oxygen or purging to remove moisture in the fuel cell. The method for stopping a gas consuming device according to any one of claims 1 to 3.

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