JP7025272B2 - Gas supply device and its stop control method - Google Patents

Description

The present invention relates to a gas supply device and a stop control method thereof.

Conventionally, as disclosed in Patent Document 1 below, a gas supply device that compresses a gas such as hydrogen gas and supplies the gas to a pressure accumulator or the like is known. In the gas supply device disclosed in Patent Document 1, in order to reduce the size of the buffer tank arranged on the suction side of the compressor, the gas supply device is arranged on the upstream side of the buffer tank when the compressor receives a stop signal. The inflow side on-off valve is closed. That is, even if a compressor stop signal is received, the compressor does not stop completely immediately. Therefore, since the compressor continues to rotate for a while with the inflow side on-off valve closed, it is possible to prevent gas from remaining in the compressor. Therefore, after the compressor is stopped, the gas returning from the compressor can be suppressed from flowing into the buffer tank, which makes it possible to reduce the size of the buffer tank.

Japanese Unexamined Patent Publication No. 2017-13186

The above-mentioned Patent Document 1 reduces the amount of gas returning to the buffer tank from the compressor arranged downstream of the buffer tank. However, in some cases, a compressor in the subsequent stage may be provided as a gas supply device. In that case, simply driving the compressor (lower stage side) with the inflow side on-off valve closed may cause compression on the lower stage side. There is a risk that the gas pressure on the suction side of the machine will rise.

Therefore, the present invention has been made in view of the above-mentioned prior art, and an object thereof is to stop gas supply in a gas supply device including a first compressor and a second compressor in the subsequent stage. At this time, the purpose is to prevent the gas pressure on the suction side of the first compressor from becoming excessive.

In order to achieve the above object, the gas supply device according to the present invention is a gas supply device to which an intermediate tank is connected and is used, and has a first suction valve, a first discharge valve, and a first compressor. A second compression unit having a first compression unit, a second suction valve, a second discharge valve, and a second compressor, and further compressing the discharge gas of the first compression unit by the second compressor, and the above. A return valve provided in a return flow path that branches from the flow path between the second suction valve and the second compressor and is connected to the flow path between the first suction valve and the first compressor. And when the gas supply from the gas supply device and the connection port to which the intermediate tank can be connected, which is provided in the flow path connecting the first compression unit and the second compression unit, is stopped. Return control that closes the second discharge valve with the first discharge valve open, closes the first suction valve and the second suction valve, and opens the return valve while continuing the operation of the first compressor. It is equipped with a stop control unit that performs the above.

The gas supply device according to the present invention is used in a state where an intermediate tank is connected to the connection port. Then, in the gas supply device, when the gas supply from the gas supply device is stopped, the return control for returning the gas in the system of the second compression unit to the connection port side is performed. That is, the compressed gas in the system of the second compression unit is returned to the suction side of the first compressor through the return flow path in which the return valve is opened. At this time, since the operation of the first compressor is continued, the gas returned to the suction side of the first compressor is sucked into the first compressor, discharged from the compressor, and connected to the connection port. It is stored in the intermediate tank. Therefore, it is possible to suppress the accumulation of gas on the suction side of the first compressor, and it is possible to prevent the gas pressure on the suction side of the first compressor from becoming excessive.

The gas supply device may further include a detection unit that detects the gas pressure between the first suction valve and the first compressor. In this case, the stop control unit refers to the pressure detected by the detection unit in the return control, and gradually opens the return valve so that the gas pressure is maintained below a predetermined pressure. Alternatively, the return valve may be repeatedly opened and closed.

In this aspect, the stop control unit opens the return valve stepwise or repeats opening and closing of the return valve in the return control. Therefore, the gas pressure on the suction side of the first compressor is maintained below a predetermined pressure. Therefore, for example, when a safety valve is provided on the suction side of the first compressor, it is possible to prevent gas from being discharged to the outside through the safety valve, and a buffer tank is provided on the suction side of the first compressor. If so, it is possible to prevent the allowable pressure of the buffer tank from being exceeded. In addition, it is possible to prevent the gas from returning too much temporarily or instantaneously.

The gas supply device includes a bypass path connected to a flow path between the second suction valve and the second compressor, and a flow path between the second compressor and the second discharge valve. , A spillback valve with an adjustable opening degree provided in the bypass path may be further provided. In this case, the stop control unit may open the spillback valve in the return control.

In this aspect, the spillback valve is opened in return control. As a result, the pressure on the discharge side and the suction side of the second compressor is equalized. Then, the compressed gas between the second discharge valve and the second compressor is returned to the suction side of the first compressor via the bypass path. At this time, since the operation of the first compressor is continued, the gas is discharged from the first compressor and pumped to the intermediate tank through the connection port. Therefore, the compressed gas existing on the discharge side of the second compressor can also be stored in the intermediate tank.

The gas supply device according to the present invention has a first compression unit having a first suction valve, a first discharge valve, and a first compressor, and a second suction valve, a second discharge valve, and a second compressor. , The second compressor that further compresses the discharged gas of the first compressor by the second compressor, and the first suction branching from the flow path between the second suction valve and the second compressor. A return valve provided in the return flow path connected to the flow path between the valve and the first compressor, and a flow path branched from the flow path connecting the first compression section and the second compression section. When the gas supply is stopped, the second discharge valve is closed, the first suction valve and the second suction valve are closed, and the first suction valve is closed. (1) A stop control unit that controls a return to open the return valve while continuing the operation of the compressor is provided.

The present invention is a stop control method for a gas supply device, wherein the gas supply device includes a first compression unit having a first suction valve, a first discharge valve, and a first compressor, a second suction valve, and a first compressor. A second compressor having two discharge valves and a second compressor, and further compressing the discharge gas of the first compressor by the second compressor, and the second suction valve and the second compressor. It is provided with a return valve provided in a return flow path that branches from the flow path between them and is connected to the flow path between the first suction valve and the first compressor. In the stop control method of the gas supply device, when the gas supply from the gas supply device is stopped, the second discharge valve is closed while the first discharge valve is open, and the first suction valve and the first suction valve are closed. The second suction valve is closed, the return valve is opened while the operation of the first compressor is continued, and gas is allowed to flow into the intermediate tank from the flow path connecting the first compression section and the second compression section.

The gas supply device may further include a detection unit that detects the pressure between the first suction valve and the first compressor. In this case, the stop control method refers to the pressure detected by the detection unit in the return control, and even if the return valve is opened stepwise so that the pressure is maintained below a predetermined pressure. Well, or the return valve may be repeatedly opened and closed.

The gas supply device includes a bypass path connected to a flow path between the second suction valve and the second compressor, and a flow path between the second compressor and the second discharge valve. , A spillback valve with an adjustable opening degree provided in the bypass path may be further provided. In this case, the stop control method may open the spillback valve when stopping the gas supply from the gas supply device.

As described above, according to the present invention, in the gas supply device including the first compressor and the second compressor in the subsequent stage, when the gas supply is stopped, the gas on the suction side of the first compressor is stopped. It is possible to prevent the pressure from becoming excessive.

It is a figure which shows roughly the structure of the gas supply device which concerns on embodiment. It is a flow diagram for demonstrating the stop control method of the gas supply device. It is a figure which shows roughly the structure of the gas supply device which concerns on other embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.

As shown in FIG. 1, the gas supply device 10 according to the present embodiment is a device that supplies gas to the gas demand side, and is a main flow path 12 through which gas flows, a low pressure side bypass path 14, and a high pressure side bypass path. A return flow path 18, a return flow path 18, and a controller 20 are provided. The low-pressure side bypass path 14, the high-pressure side bypass path 16, and the return flow path 18 are all connected to the main flow path 12. For example, the gas supply device 10 compresses hydrogen gas to a high pressure and supplies it to the demand side, but the supplied gas is not limited to hydrogen gas.

One end 12a of the main flow path 12 is configured to be connected to a gas supply source (not shown). The other end 12b of the main flow path 12 is configured to be connected to the demand side (not shown). When the gas supply device 10 is used for a hydrogen station, for example, a pressure accumulator capable of storing high-pressure gas (not shown) and a dispenser as a filling device (not shown) are provided on the demand side. The dispenser is configured to fill a tank mounted on a fuel cell vehicle or the like with high-pressure gas supplied from a pressure accumulator or a gas supply device 10. The gas supplied from the gas supply device 10 is stored in the accumulator so as to have a preset filling pressure.

The main flow path 12 includes a first compression unit 22 that compresses the gas that has flowed in through one end 12a of the main flow path 12, a second compression unit 23 that further compresses the gas compressed by the first compression unit 22, and a first compression unit. A connection port 24 located between the portion 22 and the second compression portion 23 is provided.

The first compression unit 22 includes a buffer tank 26, a first suction valve (low pressure side suction valve) 27, a first discharge valve (low pressure side discharge valve) 28, and a first compressor (low pressure side compressor) 29. , Is equipped. The buffer tank 26 is arranged on the suction side of the first compressor 29 in the main flow path 12, and the gas sucked into the first compressor 29 is stored. By providing the buffer tank 26, the pressure fluctuation on the suction side of the first compressor 29 can be suppressed. The buffer tank 26 can be omitted.

The first suction valve 27 is arranged on the upstream side of the buffer tank 26 in the main flow path 12. The first suction valve 27 is composed of an on-off valve capable of opening and closing the main flow path 12. The first discharge valve 28 is arranged on the downstream side of the first compressor 29 in the main flow path 12. The first discharge valve 28 is composed of an on-off valve capable of opening and closing the main flow path 12. The first suction valve 27 and the first discharge valve 28 are controlled to open and close by the controller 20.

The first compressor 29 is arranged between the buffer tank 26 and the first discharge valve 28 in the main flow path 12. The first compressor 29 is configured by, for example, a reciprocating compressor. The first compressor 29 is not limited to this configuration, and may be configured by, for example, a screw compressor, a turbo compressor, or the like.

The second compression unit 23 includes a second suction valve (high pressure side suction valve) 32, a second discharge valve (high pressure side discharge valve) 33, and a second compressor (high pressure side compressor) 34. .. The second suction valve 32 is arranged on the downstream side of the first discharge valve 28 in the main flow path 12. The second suction valve 32 is composed of an on-off valve capable of opening and closing the main flow path 12. The second discharge valve 33 is arranged on the downstream side of the second compressor 34 in the main flow path 12. The second discharge valve 33 is composed of an on-off valve capable of opening and closing the main flow path 12. The second suction valve 32 and the second discharge valve 33 are controlled to open and close by the controller 20.

The second compressor 34 is arranged between the second suction valve 32 and the second discharge valve 33 in the main flow path 12. The second compressor 34 is composed of a compressor that discharges gas at a discharge flow rate larger than that of the first compressor 29. Therefore, of the amount of gas sucked by the second compressor 34, the amount of gas corresponding to the difference between the discharge amounts of the two compressors 29 and 34 is covered by the gas flowing out from the intermediate tank 36 described later. The second compressor 34 is composed of, for example, a reciprocating compressor. The second compressor 34 is not limited to the reciprocating compressor, and may be configured by, for example, a screw compressor, a turbo compressor, or the like.

The connection port 24 is provided in the flow path branched from the portion between the first discharge valve 28 and the second suction valve 32 in the main flow path 12. An intermediate tank 36 can be connected to the connection port 24. That is, the gas supply device 10 according to the first embodiment is a gas supply device 10 to which the intermediate tank 36 is connected and used. The intermediate tank 36 can store gas at an allowable pressure equal to or higher than the discharge pressure of the first compressor 29.

The low-pressure side bypass path 14 is a flow path that bypasses the first compressor 29, and one end of the low-pressure side bypass path 14 is a buffer tank 26 (or a first suction valve 27) and a first compressor 29 in the main flow path 12. The other end of the low pressure side bypass path 14 is connected to a portion between the first compressor 29 and the first discharge valve 28 in the main flow path 12.

The low pressure side bypass path 14 is provided with a low pressure side spillback valve 38. The low pressure side spillback valve 38 is composed of a valve whose opening degree can be adjusted. The opening degree of the low pressure side spillback valve 38 is adjusted by a command from the controller 20.

The high-pressure side bypass path 16 is a flow path that bypasses the second compressor 34, and one end of the high-pressure side bypass path 16 is located at a portion between the second suction valve 32 and the second compressor 34 in the main flow path 12. The other end of the high pressure side bypass path 16 is connected to a portion of the main flow path 12 between the second compressor 34 and the second discharge valve 33.

The high-pressure side bypass path 16 is provided with a high-pressure side spillback valve 40. The high pressure side spillback valve 40 is composed of a valve whose opening degree can be adjusted. The opening degree of the high pressure side spillback valve 40 is adjusted by a command from the controller 20.

The return flow path 18 branches from the portion between the second suction valve 32 and the second compressor 34 in the main flow path 12, and is between the first suction valve 27 and the first compressor 29 in the main flow path 12. It is connected to the site. In the illustrated example, an example in which the return flow path 18 is connected to the buffer tank 26 is shown, but the present invention is not limited to this. For example, the return flow path 18 may be connected to a portion between the buffer tank 26 and the first suction valve 27 in the main flow path 12, or the buffer tank 26 and the first compressor 29 in the main flow path 12. It may be connected to a portion between the two, or may be connected to a portion on the buffer tank 26 side (first suction valve 27 side) rather than the low pressure side spillback valve 38 in the low pressure side bypass path 14.

A return valve 42 is provided in the return flow path 18. The return valve 42 is composed of an on-off valve that can open and close the return flow path 18. The return valve 42 is controlled to open and close by the controller 20.

The gas supply device 10 is provided with a low pressure side safety valve 44 and a high pressure side safety valve 45. The low pressure side safety valve 44 releases the gas to the outside (in the atmosphere) when the gas pressure on the suction side of the first compressor 29 reaches the set pressure. The high-pressure side safety valve 45 releases the gas to the outside (in the atmosphere) when the gas pressure on the suction side of the second compressor 34 reaches the set pressure.

The gas supply device 10 includes a first gas pressure detector 47 that detects the gas pressure on the suction side of the first compressor 29, and a second gas pressure detector that detects the gas pressure on the suction side of the second compressor 34. 48 and a discharge gas pressure detector 49 for detecting the gas pressure on the discharge side of the second compressor 34 are provided. The first gas pressure detector 47 is arranged at a portion on the buffer tank 26 side (first suction valve 27 side) of the low pressure side spillback valve 38 in the low pressure side bypass path 14. The first gas pressure detector 47 functions as a detector for detecting the gas pressure between the first suction valve 27 and the first compressor 29. The first gas pressure detector 47 may be arranged at a suction side portion (a portion between the first compressor 29 and the first suction valve 27) of the first compressor 29 in the main flow path 12. .. The second gas pressure detector 48 is arranged at a portion on the second suction valve 32 side of the high pressure side spillback valve 40 in the high pressure side bypass path 16. The second gas pressure detector 48 may be arranged at a suction side portion (a portion between the second compressor 34 and the second suction valve 32) of the second compressor 34 in the main flow path 12. .. The discharge gas pressure detector 49 is arranged at a portion (a portion between the second compressor 34 and the second discharge valve 33) on the discharge side of the second compressor 34 in the main flow path 12.

The first gas pressure detector 47, the second gas pressure detector 48, and the discharge gas pressure detector 49 output a signal corresponding to the detected pressure. The signal output from the gas pressure detectors 47 and 48.49 is input to the controller 20.

The controller 20 includes a storage unit, a calculation unit, and the like, and when the computer program stored in the storage unit is executed by the calculation unit, a predetermined function is exhibited. This function includes, for example, a stop control unit 20a. The stop control unit 20a is configured to perform return control for storing the gas existing on the downstream side of the first compressor 29 in the intermediate tank 36 when the gas supply from the gas supply device 10 is stopped. Has been done.

Here, a stop control method for the gas supply device 10 according to the present embodiment will be described with reference to FIG. 2.

When the gas supply device 10 receives a gas supply request from the demand side and is performing an operation of supplying gas to the demand side, the first suction valve 27, the first discharge valve 28, the second suction valve 32, and the second The first compressor 29 and the second compressor 34 are driven with the discharge valve 33 open. As a result, the high-pressure compressed gas is supplied from the gas supply device 10 to the demand side (high-pressure side value accumulator, dispenser, etc.). At this time, the low pressure side spillback valve 38 and the high pressure side spillback valve 40 are closed, or the opening degree is adjusted according to the pressure on the discharge side of the compressors 29 and 34.

By the operation of the first compressor 29, the gas in the buffer tank 26 is sucked into the first compressor 29, and the first compressor 29 compresses and discharges the sucked gas. The second compressor 34 sucks and compresses the gas discharged from the first compressor 29 and the gas stored in the intermediate tank 36. The gas discharged from the second compressor 34 is supplied to the demand side through the main flow path 12. During this gas supply operation, for example, when the pressure in the accumulator reaches the set filling pressure, the dispenser outputs an operation stop command of the gas supply device 10.

When the controller 20 receives the stop command (step ST1), the stop control unit 20a starts the control for stopping the gas supply from the gas supply device 10. In this stop control, the return control of returning the compressed gas in the system of the second compressor 34 to the intermediate tank 36 is performed. The compressed gas in the system referred to here includes the compressed gas existing in the flow path between the second suction valve 32 and the second compressor 34. When the high-pressure side spillback valve 40 is open, the compressed gas existing between the second compressor 34 and the second discharge valve 33 is also included in the compressed gas in the system.

When the controller 20 receives the stop command, the stop control unit 20a controls to close the first suction valve 27 and the second suction valve 32, and also controls to repeatedly open and close the return valve 42 (step ST2). At this time, the first discharge valve 28 and the second discharge valve 33 are maintained in an open state. The first compressor 29 and the second compressor 34 do not stop. Therefore, the operation of the first compressor 29 and the second compressor 34 is continued. At this time, since the second suction valve 32 is in the closed state, the space between the first compressor 29 and the second compressor 34 is cut off, and the gas discharged from the first compressor 29 is the second compression unit. Instead of flowing into 23, it flows into intermediate tank 36. On the other hand, the gas existing on the downstream side of the second suction valve 32 is sucked into the second compressor 34 and compressed by the second compressor 34. At this time, the opening degree of the high pressure side spillback valve 40 is controlled with an opening degree within a range in which the detection value of the second gas pressure detector 48 does not exceed the set pressure of the high pressure side safety valve 45. Therefore, the gas discharged from the second compressor 34 is returned to the suction side of the second compressor 34 through the high-pressure side bypass path 16, and this gas is sent to the buffer tank 26 through the return flow path 18.

Since the second compressor 34 continues to operate with the suction side of the second compressor 34 closed, the pressure on the discharge side of the second compressor 34 gradually decreases. At this time, the gas pressure on the discharge side of the second compressor 34 is monitored by the discharge gas pressure detector 49 (step ST3). When the gas pressure P3 detected by the discharge gas pressure detector 49 becomes, for example, 40 MPaG or less, the stop control unit 20a controls to close the second discharge valve 33 and does not exceed the set pressure of the high pressure side safety valve 45. The opening control of the high pressure side spillback valve 40 in the range is terminated, and the high pressure side spillback valve 40 is controlled to be fully opened (step ST4). As a result, the gas pressure on the discharge side and the gas pressure on the suction side of the second compressor 34 are equalized. That is, after the detected pressure P3 on the discharge side of the second compressor 34 becomes 40 MPaG or less, the high pressure side spillback valve 40 is opened to the fully open state, so that the gas pressure on the suction side of the second compressor 34 increases. It is suppressed that the set pressure of the high pressure side safety valve 45 is exceeded. Further, since the high-pressure side spillback valve 40 is open, the high-pressure compressed gas existing on the discharge side of the second compressor 34 also passes through the high-pressure side bypass path 16 and the return flow path 18 to the first compressor 29. It is returned to the suction side of the above and flows into the buffer tank 26. By the time the high-pressure compressed gas is returned to the buffer tank 26, the gas in the buffer tank 26 has already been sent to the intermediate tank 36 by the operation of the first compressor 29. Therefore, even if the high-pressure compressed gas is returned to the buffer tank 26, it is possible to prevent the gas pressure on the suction side of the first compressor 29 from exceeding the set pressure of the low-pressure side safety valve 44. Then, the gas in the buffer tank 26 is sucked by the first compressor 29 and pumped to the intermediate tank 36. Therefore, gas that cannot be covered by the buffer tank 26 alone can be stored in the intermediate tank 36. Note that step ST4 is not limited to the control of fully opening the high pressure side spillback valve 40. For example, the opening degree may be controlled according to the detection pressure of the discharge gas pressure detector 49 without depending on the detection pressure of the second gas pressure detector 48.

At this time, the stop control unit 20a continues to control the opening / closing of the return valve 42. In the opening / closing control, the detection pressure by the first gas pressure detector 47 is referred to, and the return valve 42 is repeatedly opened / closed so that the detected pressure is maintained below the preset pressure. That is, the stop control unit 20a controls to close the return valve 42 when the detection pressure by the first gas pressure detector 47 exceeds the upper limit value, and open the return valve 42 by a predetermined opening degree when the detection pressure falls below the lower limit value. .. As a result, the gas pressure on the suction side of the first compressor 29 is maintained below a predetermined pressure. Therefore, it is suppressed that the gas pressure on the suction side of the first compressor 29 exceeds the set pressure of the low pressure side safety valve 44. That is, the preset pressure with which the detected pressure is referred to is a pressure equal to or lower than the set pressure of the low pressure side safety valve 44.

The opening / closing control of the return valve 42 may be, for example, a control in which the return valve 42 is opened and immediately closed for a very short time of less than 1 second. In this case, even if the high-pressure compressed gas is returned from the discharge side of the second compressor 34 to the suction side of the first compressor 29 through the return flow path 18, the gas pressure is temporary on the suction side of the first compressor 29. It is possible to prevent the pressure from exceeding the set pressure of the low pressure side safety valve 44. In this case, it is also possible to omit the first gas pressure detector 47. Further, in the opening / closing control, the return valve 42 may be gradually opened.

Even after the high-pressure side spillback valve 40 is opened, the first compressor 29 and the second compressor 34 continue to operate. Then, when the detection pressure P3 of the discharge gas pressure detector 49 becomes equal to or lower than the set pressure (for example, 5 MPaG), the stop control unit 20a controls to stop the second compressor 34 (steps ST5 and ST6). The operation may be continued without stopping the second compressor 34. Then, the detection pressure P2 (the gas pressure on the suction side of the second compressor 34) of the second gas pressure detector 48 becomes equal to or less than the set pressure (for example, 5 MPaG), and the detection pressure P1 (the detection pressure P1 of the first gas pressure detector 47). When the suction side gas pressure of the first compressor 29 becomes equal to or lower than the set pressure (for example, 0.45 MPaG), the stop control unit 20a ends the open / close control of the return valve 42 and closes the return valve 42 (step ST7, ST8). As a result, the return control ends.

As described above, in the gas supply device 10 according to the present embodiment, when the gas supply to the demand side is stopped, the return control for returning the gas in the system of the second compression unit 23 to the connection port 24 side is performed. Will be. That is, the compressed gas in the system of the second compression unit 23 is returned to the suction side of the first compressor 29 through the return flow path 18 in which the return valve 42 is opened. At this time, since the operation of the first compressor 29 is continued, the gas returned to the suction side of the first compressor 29 is sucked into the first compressor 29 and discharged from the compressor 29, and is discharged from the connection port. It is stored in the intermediate tank 36 connected to the 24. Therefore, it is possible to prevent gas from accumulating on the suction side of the first compressor 29, and thus it is possible to prevent the gas pressure on the suction side of the first compressor 29 from becoming excessive.

Further, in the present embodiment, the stop control unit 20a repeatedly opens and closes the return valve 42 in the return control. Therefore, the gas pressure on the suction side of the first compressor 29 is maintained below a predetermined pressure. Therefore, it is possible to prevent the gas from being discharged to the outside (into the atmosphere) through the low-pressure side safety valve 44, and it is possible to prevent the pressure from exceeding the allowable pressure of the buffer tank 26. In addition, it is possible to prevent the gas from returning too much to the buffer tank 26 temporarily or instantaneously.

Further, in the present embodiment, in the return control, the high pressure side spillback valve 40 is opened when the gas pressure on the suction side of the second compressor 34 becomes equal to or lower than the set pressure. As a result, the pressure on the discharge side and the suction side of the second compressor 34 is equalized. Then, the compressed gas between the second discharge valve 33 and the second compressor 34 is returned to the suction side of the first compressor 29 via the high-pressure side bypass path 16 and the return flow path 18. At this time, since the operation of the first compressor 29 is continued, the gas is discharged from the first compressor 29 and is pressure-fed to the intermediate tank 36 through the connection port 24. Therefore, the compressed gas existing on the discharge side of the second compressor 34 can also be stored in the intermediate tank 36.

The present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the gas supply device 10 in which the connection port 24 is provided in the flow path branched from the main flow path 12 and the intermediate tank 36 is connected to the connection port 24 has been described, but the present invention is limited to this. It is not something that can be done. As shown in FIG. 2, the gas supply device 10 may have a configuration in which the connection port 24 is omitted and an intermediate tank 36 is provided in a flow path branched from the main flow path 12. The return control in this case is also the same as the return control of the gas supply device 10 according to the embodiment.

In the above embodiment, the low pressure side bypass path 14 and the high pressure side bypass path 16 are provided, but the present invention is not limited to this. At least one of the low pressure side bypass path 14 and the high pressure side bypass path 16 may be omitted. It is also possible to omit the second gas pressure detector 48 and the discharge gas pressure detector 49. When the high-pressure side bypass path 16 is omitted, the second gas pressure detector 48 and the high-pressure side safety valve 45 are arranged at the suction side portion of the second compressor 34 in the main flow path 12. In this case, step ST3 and step ST4 are omitted, and when the determination in step ST7 is YES, the second discharge valve 33 is closed. When the low pressure side bypass path 14 is omitted, the first gas pressure detector 47 is arranged at the suction side portion of the first compressor 29 in the main flow path 12.

10 Gas supply device 12 Main flow path 14 Low pressure side bypass path 16 High pressure side bypass path 18 Return flow path 20 Controller 20a Stop control unit 22 First compression unit 23 Second compression unit 24 Connection port 26 Buffer tank 27 First suction valve 28 1st discharge valve 29 1st compressor 32 2nd suction valve 33 2nd discharge valve 34 2nd compressor 36 Intermediate tank 38 Low pressure side spillback valve 40 High pressure side spillback valve 42 Return valve 47 1st gas pressure detector 48 2nd gas pressure detector 49 Discharge gas pressure detector

Claims (7)

A gas supply device to which an intermediate tank is connected and used.
A first compression unit having a first suction valve, a first discharge valve, and a first compressor,
A second compression unit having a second suction valve, a second discharge valve, and a second compressor, and further compressing the discharge gas of the first compression unit by the second compressor.
A return provided in a return flow path that branches from the flow path between the second suction valve and the second compressor and is connected to the flow path between the first suction valve and the first compressor. With a valve,
A connection port provided in a flow path connecting the first compression unit and the second compression unit and to which the intermediate tank can be connected,
When the gas supply from the gas supply device is stopped, the second discharge valve is closed with the first discharge valve open, and the first suction valve and the second suction valve are closed, and the first compression is performed. A gas supply device including a stop control unit that controls a return to open the return valve while continuing the operation of the machine. In the gas supply device according to claim 1,
Further, a detection unit for detecting the gas pressure between the first suction valve and the first compressor is provided.
The stop control unit refers to the pressure detected by the detection unit in the return control, and gradually opens the return valve or gradually opens the return valve so that the gas pressure is maintained below a predetermined pressure. A gas supply device that repeatedly opens and closes the return valve. In the gas supply device according to claim 1 or 2.
A bypass path connected to a flow path between the second suction valve and the second compressor, and a flow path between the second compressor and the second discharge valve.
A spillback valve with an adjustable opening provided in the bypass path,
Further prepare
The stop control unit is a gas supply device that opens the spillback valve in the return control. A first compression unit having a first suction valve, a first discharge valve, and a first compressor,
A second compression unit having a second suction valve, a second discharge valve, and a second compressor, and further compressing the discharge gas of the first compression unit by the second compressor.
A return provided in a return flow path that branches from the flow path between the second suction valve and the second compressor and is connected to the flow path between the first suction valve and the first compressor. With a valve,
An intermediate tank provided in a flow path branched from the flow path connecting the first compression unit and the second compression unit, and
When the gas supply is stopped, the second discharge valve is closed with the first discharge valve open, the first suction valve and the second suction valve are closed, and the operation of the first compressor is continued. A gas supply device including a stop control unit that controls a return to open the return valve. It is a stop control method for gas supply equipment.
The gas supply device is
A first compression unit having a first suction valve, a first discharge valve, and a first compressor,
A second compression unit having a second suction valve, a second discharge valve, and a second compressor, and further compressing the discharge gas of the first compression unit by the second compressor.
A return provided in a return flow path that branches from the flow path between the second suction valve and the second compressor and is connected to the flow path between the first suction valve and the first compressor. With a valve,
Equipped with
When the gas supply from the gas supply device is stopped, the second discharge valve is closed with the first discharge valve open, and the first suction valve and the second suction valve are closed, and the first compression is performed. A stop control method for a gas supply device, in which the return valve is opened while continuing the operation of the machine, and gas is flowed into an intermediate tank from a flow path connecting the first compression unit and the second compression unit. In the stop control method according to claim 5,
Further, a detection unit for detecting the pressure between the first suction valve and the first compressor is provided.
In the return control, the pressure detected by the detection unit is referred to, and the return valve is opened stepwise or the return valve is repeatedly opened and closed so that the pressure is maintained below a predetermined pressure. Stop control method for gas supply equipment. In the stop control method according to claim 5 or 6,
The gas supply device is
A bypass path connected to a flow path between the second suction valve and the second compressor, and a flow path between the second compressor and the second discharge valve.
A spillback valve with an adjustable opening provided in the bypass path,
Further prepare
A method for controlling a stop of a gas supply device, which opens the spillback valve when the gas supply from the gas supply device is stopped.

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