Reciprocating compressor

Abstract

To prevent suction pressure of a compression part on a low-pressure side from increasing excessively, even when hydrogen gas leaks to the compression part on the low-pressure side from a compression part.SOLUTION: A reciprocating compressor 10 comprises a third stage compression unit 13, a fifth stage compression unit 15, a drive unit 20, a discharge mechanism 45, a pressure sensor 47, and a discharge control unit 49a. The discharge mechanism 45 can discharge hydrogen gas from a second connection pipe 32 through which the hydrogen gas suctioned into the third stage compression unit 13 flows. The discharge control unit 49a controls the discharge mechanism 45 to discharge the hydrogen gas from the second connection pipe 32 when the pressure of the hydrogen gas detected by the pressure sensor is higher than a preset value.SELECTED DRAWING: Figure 1

Claims

1. A reciprocating compressor for compressing hydrogen gas, A low-pressure stage compression section for compressing hydrogen gas has a low-pressure stage piston, a low-pressure stage cylinder section housing the low-pressure stage piston, and a group of piston rings attached to the low-pressure stage piston. A high-pressure stage compression section comprises a high-pressure stage piston connected to the low-pressure stage piston, a high-pressure stage cylinder section housing the high-pressure stage piston and connected to the low-pressure stage cylinder section, and a group of piston rings attached to the high-pressure stage piston, and compresses the hydrogen gas after it has been compressed in the low-pressure stage compression section. A drive unit that drives the high-pressure stage compression unit and the low-pressure stage compression unit, A discharge mechanism capable of discharging hydrogen gas from the suction side passage through which the hydrogen gas drawn into the low-pressure compression section flows, A pressure sensor for detecting the pressure of hydrogen gas drawn into the low-pressure compression section, The system includes a discharge control unit that controls the discharge mechanism to discharge hydrogen gas from the suction side passage when the pressure of the hydrogen gas detected by the pressure sensor is higher than a preset value, The aforementioned setting value is the normal pressure value of hydrogen gas drawn into the low-pressure stage compression section when the suction valve of the low-pressure stage compression section is opened by the differential pressure between the pressure in the suction-side passage and the pressure in the compression chamber of the low-pressure stage compression section, in a reciprocating compressor.

2. A reciprocating compressor for compressing hydrogen gas, A low-pressure stage compression section for compressing hydrogen gas has a low-pressure stage piston, a low-pressure stage cylinder section housing the low-pressure stage piston, and a group of piston rings attached to the low-pressure stage piston. A high-pressure stage compression section comprises a high-pressure stage piston connected to the low-pressure stage piston, a high-pressure stage cylinder section housing the high-pressure stage piston and connected to the low-pressure stage cylinder section, and a group of piston rings attached to the high-pressure stage piston, and compresses the hydrogen gas after it has been compressed in the low-pressure stage compression section. A drive unit that drives the high-pressure stage compression unit and the low-pressure stage compression unit, A device that can discharge hydrogen gas from the intake side passage through which hydrogen gas drawn into the low-pressure stage compression section flows. Discharge mechanism, A pressure sensor for detecting the pressure of hydrogen gas drawn into the low-pressure stage compression section or the pressure of hydrogen gas discharged from the low-pressure stage compression section, The system includes a discharge control unit that controls the discharge mechanism to discharge hydrogen gas from the suction side passage when the pressure of the hydrogen gas detected by the pressure sensor is higher than a preset value, The drive unit has a rotatable motor, The aforementioned reciprocating compressor, The drive unit includes an inverter capable of adjusting the rotational speed of the motor, A reciprocating compressor further comprising: a rotation speed control unit that controls the inverter to increase the rotation speed of the motor in order to compensate for the amount of hydrogen gas discharged from the suction side passage when hydrogen gas is discharged from the suction side passage.

3. The pressure sensor is located in the suction side flow path, The discharge mechanism comprises a gas discharge passage connected to the suction side passage, and a discharge valve located in the gas discharge passage and capable of adjusting the valve opening. The reciprocating compressor further includes an auxiliary pressure sensor located downstream of the discharge valve in the gas discharge passage. The reciprocating compressor according to claim 2, wherein the rotational speed control unit is configured to increase the rotational speed of the motor to compensate for an amount corresponding to the discharge flow rate of hydrogen gas derived based on the pressure detected by the pressure sensor, the pressure detected by the auxiliary pressure sensor, and the flow rate characteristics of the discharge valve.

4. The discharge mechanism comprises a gas discharge passage connected to the suction side passage, an on-off valve located in the gas discharge passage, and an orifice located downstream of the on-off valve in the gas discharge passage. The reciprocating compressor further includes an auxiliary pressure sensor located downstream of the orifice in the gas discharge passage. The reciprocating compressor according to claim 2, wherein the rotational speed control unit is configured to increase the rotational speed of the motor in order to supplement the hydrogen gas discharge flow rate derived based on the pressure detected by the pressure sensor, the pressure detected by the auxiliary pressure sensor, and the throttling ratio of the gas discharge passage by the orifice.

5. The hydrogen gas discharged from the aforementioned reciprocating compressor is supplied to an accumulator consisting of a tank. A demand-side pressure sensor located in the accumulator, or located in the demand-side connection channel connecting the reciprocating compressor and the accumulator to each other, A demand-side temperature sensor located in the accumulator or the demand-side connection channel, An estimation unit that estimates the amount of density change per unit time of hydrogen gas stored in the accumulator based on the pressure detected by the demand-side pressure sensor, the temperature detected by the demand-side temperature sensor, and the tank capacity of the accumulator. Furthermore, The reciprocating compressor according to claim 2, wherein the rotational speed control unit is configured to increase the rotational speed of the motor by an amount equivalent to the difference between the amount of change in hydrogen gas density per unit time accumulated in the accumulator when there is no leakage of hydrogen gas from the high-pressure stage compression unit to the low-pressure stage compression unit and the amount of change in hydrogen gas density per unit time estimated by the estimation unit.

6. A reciprocating compressor for compressing hydrogen gas, A low-pressure stage compression section for compressing hydrogen gas has a low-pressure stage piston, a low-pressure stage cylinder section housing the low-pressure stage piston, and a group of piston rings attached to the low-pressure stage piston. An intermediate compression section compresses the hydrogen gas discharged from the low-pressure compression section, A high-pressure stage compression section comprises a high-pressure stage piston connected to the low-pressure stage piston, a high-pressure stage cylinder section housing the high-pressure stage piston and connected to the low-pressure stage cylinder section, and a group of piston rings attached to the high-pressure stage piston, and compresses the hydrogen gas discharged from the intermediate stage compression section. A drive unit that drives the low-pressure stage compression section, the intermediate stage compression section, and the high-pressure stage compression section, A discharge mechanism capable of discharging hydrogen gas from the suction side passage through which the hydrogen gas drawn into the low-pressure compression section flows, A pressure sensor for detecting the pressure of hydrogen gas drawn into the low-pressure compression section, The system includes a discharge control unit that controls the discharge mechanism to discharge hydrogen gas from the suction side passage when the pressure of the hydrogen gas detected by the pressure sensor is higher than a preset value, A reciprocating compressor in which the set value is the normal pressure value of hydrogen gas drawn into the low-pressure stage compression section when the suction valve of the low-pressure stage compression section is opened by the differential pressure between the pressure of hydrogen gas drawn into the low-pressure stage compression section and the pressure in the compression chamber of the low-pressure stage compression section.

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