JP2009209905A - Gas leakage preventive system of reciprocating compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas leakage preventive system of a reciprocating compressor having no risk of atmospheric pollution, take-fire and an explosion, by preventing a little leakage from a shaft seal part, even in a horizontal large compressor. <P>SOLUTION: This gas leakage preventive system of the reciprocating compressor 1 having suction pressure of 1 MPa or more, has a leakage gas recovery line 7 for recovering and returning leakage gas from the shaft seal part 6 of the reciprocating compressor 1 to the suction side, a buffer tank 8 interposed in this leakage gas recovery line 7, a small compressor 11 interposed in the succeeding leakage gas recovery line 7, a shaft seal part communicating line 9 for communicating a shaft seal part 16 of this small compressor 11 with the leakage gas recovery line 7, and a bypass line 10 for communicating the buffer tank 8 with the leakage gas recovery line 7 on the delivery side of the small compressor 11 and interposing a bypass valve 10a. When a gas quantity supplied to the small compressor 11 is little, in its turn, when processing capacity of this small compressor 11 is excessive, the leakage gas is returned to the buffer tank 8 by opening the bypass valve 10a. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a gas leakage prevention system for a reciprocating compressor that prevents slight leakage of compressed gas from a shaft seal portion of the reciprocating compressor.

  For compression of natural gas, flammable and explosive gas such as hydrogen, toxic gas such as carbon monoxide, or refrigerant gas such as carbon dioxide, high pressure is obtained, and industrial reciprocating compressors are often used. Yes. At that time, if there is a slight leakage of compressed gas from the shaft seal of such a reciprocating compressor, there is a risk of ignition, explosion, or harm to the human body. Technology).

  A gas leakage prevention technique according to a conventional example of such a reciprocating compressor will be described below with reference to FIGS. FIG. 3 is an overall schematic explanatory view of a gas compressor according to a conventional example, FIG. 4 is an enlarged cross-sectional view of a distance piece shaft seal device of a gas compressor according to a conventional example, and FIG. 5 is petroleum at the American Petroleum Institute (API), It is explanatory drawing of the standard which concerns on the reciprocating compressor for chemical and gas industries.

  First, a distance piece shaft seal device for a gas compressor according to a conventional example is provided with a distance piece 30 connected to the cylinder 28 between the cylinder 28 and the crankcase 29 as shown in FIGS. A cylinder shaft sealing device 40 is provided on the partition wall 31 on the cylinder 28 side, and a distance piece shaft sealing device 50 is provided on the partition wall 32 on the crankcase 29 side of the distance piece 30 so that the compressed gas leaks to the crankcase 29 side. Is to prevent. In order to improve the sealing performance of the distance piece shaft seal device 50, oil seals 513 and 514 and a V-shaped packing ring 55 are used, and the gas accumulated in the distance piece 30 is leaked to the crankcase 29 side. However, it is configured to return to the suction line side of the gas compressor (see Patent Document 1).

  According to the distance piece shaft sealing device 50, the suction line and the distance piece 30 are communicated with each other in order to discharge the gas leaked into the distance piece 30, but the suction pressure is high (for example, 1 MPa or more). In this case, the pressure difference between the front and rear of the distance piece shaft seal device 50 becomes too large, and due to the pressure difference, the force for pressing the piston rod 60 of the V-shaped packing ring 55 becomes excessive, and the V-shaped packing ring 55 It tends to cause abnormal wear and is inappropriate. Further, in the case of a horizontal large compressor, the vibration in the radial direction of the piston rod 60 is larger than that in the vertical compressor, and as a result, the oil seals 513 and 514 and the V-shaped packing ring 55 have insufficient followability to the vibration. However, the deterioration of sealing performance is inevitable.

  On the other hand, as shown in FIG. 5, a reciprocating compressor for oil, chemical and gas industries in which a shaft seal 70 (Pressure Packing) is provided between a cylinder side 71 and a distance piece side 72 is known. . In this reciprocating compressor, an inert protective gas (Inert Buffer gas) is supplied from the B line connected to the shaft seal portion 70 and simultaneously discharged from the G line to the outside of the system (Non-Patent Document 1). reference).

Such a system for gas leakage in the shaft seal 70 is generally adopted in a large compressor exceeding 100 kW, and a part of the gas compressed by the cylinder causes the G line to leak due to leakage from the shaft seal 70. Through the atmosphere. However, in such a system, when the compressed gas is a toxic gas or a flammable gas, it is necessary to have equipment for performing a predetermined process such as dilution and detoxification before releasing them outside the system such as the atmosphere. Become. In the case of a compressor that circulates refrigerant gas in a closed loop, the frequency of replenishment of the refrigerant gas increases.
JP 2002-339866 A “Reciprocating compressors for the petroleum, chemical and gas industries”, American Petroleum Institute Standard 618 (USA), American Petroleum Institute, June 1995, 4th edition, p. 131-132 (Reciprocating Compressor for Petroleum, Chemical, and Gas Industry Services, API STANDARD 618 (USA), American Petroleum Institute, June 1995, Fourth Edition, p. 131-132)

  Accordingly, the object of the present invention is to prevent slight leakage from the shaft seal portion even in a horizontal large compressor, without polluting the atmosphere, there is no danger of ignition or explosion, and reducing the gas replenishment frequency. An object of the present invention is to provide a gas leakage prevention system for a reciprocating compressor.

  In order to achieve the above object, the means adopted by the gas leakage prevention system for a reciprocating compressor according to claim 1 of the present invention includes a reciprocating compressor, a shaft seal portion of the reciprocating compressor, and the reciprocating motion. A leak gas recovery line connecting the suction side of the compressor, a buffer tank interposed in the leak gas recovery line and storing leak gas leaked from the shaft seal portion of the reciprocating compressor, and a buffer tank A small compressor that is interposed in the subsequent leak gas recovery line and sucks in the leak gas stored in the buffer tank and pressurizes the leak gas, and the leak gas is boosted by the small compressor and then leaked. It is configured to return to the suction side of the reciprocating compressor via a gas recovery line.

  And a bypass line communicating with the buffer tank and a leakage gas recovery line on the discharge side of the small compressor, and a bypass valve interposed in the bypass line, and is supplied from the buffer tank to the small compressor When the amount of gas to be produced is too small, the bypass valve is opened, and part of the gas discharged from the small compressor is returned to the buffer tank via the bypass line.

  Further, the means adopted by the gas leakage prevention system for a reciprocating compressor according to claim 2 of the present invention includes the buffer tank in addition to the configuration of the gas leakage prevention system for the reciprocating compressor according to claim 1 of the present invention. A tank pressure detecting means for detecting the pressure of the tank, and when the pressure signal detected by the tank pressure detecting means becomes lower than a predetermined pressure, the amount of gas supplied from the buffer tank to the small compressor is too small. As a case, the bypass valve is configured to be opened.

  Furthermore, the means adopted by the gas leakage prevention system for the reciprocating compressor according to claim 3 of the present invention is the reciprocating compressor, the shaft seal portion of the reciprocating compressor, and the suction side of the reciprocating compressor. A leak gas recovery line connected to the reciprocating compressor, a buffer tank for storing leak gas leaked from the shaft seal portion of the reciprocating compressor, and the leak gas following the buffer tank A small compressor that is interposed in the recovery line and sucks in the leaked gas stored in the buffer tank and pressurizes the leaked gas, and the leaked gas is boosted by the small compressor and then passed through the leaked gas recovery line. A tank pressure detecting means for detecting the pressure of the buffer tank, an inverter for commanding the rotational speed of the drive motor of the small compressor, A controller for calculating the rotational speed of the drive motor based on the pressure signal detected by the pressure detection means, and the rotational speed of the drive motor of the small compressor by the frequency signal transmitted from the controller to the inverter It is comprised so that it may control.

  And the means which the gas leakage prevention system of the reciprocating compressor according to claim 4 of the present invention adopts, in addition to the configuration of the gas leakage preventing system of the reciprocating compressor according to claims 1 to 3 of the present invention, A shaft seal portion communication line is provided that connects the shaft seal portion of the small compressor and the leakage gas recovery line on the suction side of the small compressor.

  Further, the means adopted by the gas leakage prevention system for a reciprocating compressor according to claim 5 of the present invention is not limited to the configuration of the gas leakage prevention system for a reciprocating compressor according to claims 1 to 3 of the present invention. The small compressor is a hermetic compressor.

  According to the gas leakage prevention system for a reciprocating compressor according to claim 1 of the present invention, the leakage gas leaked from the shaft seal portion of the reciprocating compressor can be reliably returned to the suction side of the reciprocating compressor. The leakage gas leaked from the shaft seal portion of the reciprocating compressor can be prevented from being released outside the system including the reciprocating compressor (compressed gas leakage). Even in a large reciprocating compressor that is difficult to achieve a sealed structure, leakage of compressed gas can be prevented.

  When the amount of gas supplied from the buffer tank to the small compressor is too small, part of the leaked gas leaking from the shaft seal of the reciprocating compressor is returned to the suction side of the reciprocating compressor, The part can be returned to the buffer tank, so excessive leakage gas can be returned to the suction side of the reciprocating compressor, or the small compressor can excessively absorb leakage gas leaked from the shaft seal of the reciprocating compressor. Can be avoided.

  Further, according to the gas leakage prevention system for a reciprocating compressor according to claim 2 of the present invention, the buffer tank can be appropriately removed from the buffer tank based on the pressure signal detected by the tank pressure detecting means for detecting the pressure of the buffer tank. It is possible to determine that the amount of gas supplied to the small compressor is too small, avoiding excessive return of leaked gas to the suction side of the reciprocating compressor, and avoiding excessive intake of leaked gas by the small compressor Can be made more reliable.

  Furthermore, according to the gas leakage prevention system for a reciprocating compressor according to claim 3 of the present invention, a small compressor that re-pressurizes according to the amount of leaked gas leaked from the shaft seal portion of the reciprocating compressor. The load (processing amount) can be optimized.

  According to the gas leakage prevention system for a reciprocating compressor according to claim 4 of the present invention, not only the leakage gas leaked from the shaft seal portion of the reciprocating compressor but also the leak gas leaked from the shaft seal portion of the small compressor. However, since it can be reliably returned to the suction side of the reciprocating compressor, the leakage of the compressed gas can be further prevented.

  Further, according to the gas leakage prevention system for a reciprocating compressor according to claim 5 of the present invention, the prevention of compressed gas leakage can be further strengthened.

  First, a gas leakage prevention system for a reciprocating compressor according to Embodiment 1 of the present invention will be described below with reference to FIG. FIG. 1 is a schematic system diagram showing a gas leak prevention system for a reciprocating compressor according to Embodiment 1 of the present invention as an example of application to a heat pump. A reciprocating compressor 1 according to Embodiment 1 of the present invention includes a crank mechanism 2 that converts rotational motion by a drive motor M1 into reciprocating motion, a piston rod 3 that is connected to the crank mechanism 2 at one end, and the piston And a piston 4 connected to the other end of the rod 3.

  The crank mechanism 2 is housed and installed in a crankcase 2a, and the piston 4 is housed in a reciprocating manner while sliding on the inner wall of the cylinder 4a. The crankcase 2 a and the cylinder 4 a are connected via a distance piece 5. Further, the partition wall 6a separating the cylinder 4a and the distance piece 5 is provided with a through hole for allowing the piston rod 3 to pass therethrough. The through hole has a compressed gas compressed in the cylinder 4a. A shaft seal 6 for preventing leakage is provided.

  The shaft seal portion 6 employs a seal structure composed of a seal ring, a V-shaped packing ring, or the like. Then, the piston 4 is reciprocated in the cylinder 4a by the crank mechanism 2, the high-pressure suction gas (for example, 1 MPa or more) supplied from the suction port 1a into the cylinder 4a is compressed by the piston 4, and A high-pressure compressed gas is obtained at the discharge port 1b.

  In the heat pump using the reciprocating compressor 1, the reciprocating compressor 1, the high pressure discharge line 18a, the condenser 19, the expansion valve 20, the evaporator 21, and the high pressure suction line 18b are connected in a closed loop to circulate. A line 18 is formed. In the heating operation, in the evaporator 21, the gas expanded by the expansion valve 20 exchanges heat with the heat source side brine to absorb heat from the brine, and the condenser 19 gives heat to the load side hot water. On the other hand, in the cooling operation, in the evaporator 21, the gas expanded by the expansion valve 20 exchanges heat with the cold water on the load side to remove heat, and in the condenser 19, exchanges heat with brine to dissipate heat to the brine. .

  The opening of the expansion valve 20 is controlled by the controller 21b so that the detected value of the pressure gauge 22 attached to the high-pressure discharge line 18a, that is, the so-called condensation pressure P2 falls within a certain pressure range. However, the opening degree control of the expansion valve 20 is not limited to this. For example, a temperature sensing cylinder is provided on the outlet side of the evaporator 21, and the opening degree of the expansion valve 20 is detected by the temperature (evaporation). Temperature), a thermometer is provided on the inlet / outlet side of the evaporator 21, a temperature gauge is controlled on the inlet / outlet side, or a thermometer is provided in place of the pressure gauge 22 for reciprocating motion. A form such as control according to the degree of superheat on the discharge side of the compressor 1 is often used.

  In such a heat pump, the gas circulated in the circulation line 18 is an HCFC or HFC refrigerant, or a so-called natural refrigerant such as ammonia, propane or carbon dioxide (hereinafter collectively referred to as refrigerant gas or simply gas). Also called). In the reciprocating compressor 1, when such refrigerant gas is compressed, gas leakage from the shaft seal 6 is unavoidable as the refrigerant gas to be compressed becomes higher in pressure.

  Therefore, the gas leakage prevention system for a reciprocating compressor according to Embodiment 1 of the present invention is configured as follows. That is, the gas leakage prevention system of the reciprocating compressor 1 includes a vent line 7a for collecting leaked gas from the shaft seal portion 6, a buffer tank 8, a low pressure suction line 7b, and a suction port 11a of the small compressor 11. Are connected to the discharge port 11b, the low-pressure discharge line 7c, the check valve 17 and the high-pressure suction line 18b (or the suction port 1a) of the reciprocating compressor 1. A leakage gas recovery line 7 is provided.

  That is, the leak gas recovery line 7 connects the shaft seal portion 6 of the reciprocating compressor 1 and the suction port 1a (suction side) via various facilities such as the buffer tank 8. As will be described later, the leak gas recovery line 7 has a function of recovering leak gas from the shaft seal portion 6 of the reciprocating compressor 1 and returning it to the suction port 1a (suction side).

  Similar to the reciprocating compressor 1, the small compressor 11 includes a crank mechanism 12 that converts the rotational motion of the drive motor M2 into reciprocating motion, a piston rod 13 that is connected to the crank mechanism 12 at one end, And a piston 14 connected to the other end of the piston rod 13.

  The crank mechanism 12 is housed and installed in a crankcase 12a, and the piston 14 is housed in a reciprocating manner while sliding on the inner wall of the cylinder 14a. The crankcase 12 a and the cylinder 14 a are connected via a distance piece 15. Further, the partition wall 16a separating the cylinder 14a and the distance piece 15 is provided with a through hole for allowing the piston rod 13 to pass therethrough. The through hole has a compressed gas compressed in the cylinder 14a. A shaft seal 16 for preventing leakage is provided.

  The shaft seal portion 16 also employs a seal structure made up of a seal ring, a V-shaped packing ring, or the like. The piston 14 is reciprocated in the cylinder 14a by the crank mechanism 12, and the gas supplied into the cylinder 4a from the suction port 11a is compressed by the piston 14 so that compressed gas is obtained at the discharge port 11b. It is configured. Further, a shaft seal portion communication line 9 is connected to the low pressure suction line 7 b and communicates with the shaft seal portion 16 of the small compressor 11. On the other hand, a bypass line 10 is connected to the low pressure discharge line 7c, and a bypass valve 10a is interposed in the bypass line 10.

  In such a reciprocating compressor gas leakage prevention system, the leaked gas leaked from the shaft seal 6 of the reciprocating compressor 1 is introduced into the buffer tank 8 from the vent line 7a and stored. The leaked gas stored in the buffer tank 8 is sucked into the suction port 11a of the small compressor 11 through the low pressure suction line 7b, and is compressed and then discharged to the low pressure discharge line 7c. At this time, the amount of leaked gas leaking from the shaft seal portion 6, and hence the amount of gas introduced into the buffer tank 8 via the vent line 7 a (hereinafter also referred to as a vent amount) is not constant. Therefore, it is desirable that the small compressor 11 is capable of processing the maximum vent amount normally assumed.

  The amount of vent supplied to the small compressor 11 via the low-pressure suction line 7b is smaller than the processing capacity of the small compressor 11, that is, the vent amount (gas amount) is too small (the processing capacity of the small compressor 11 is excessive). ), The bypass valve 10a interposed in the bypass passage 10 is opened, and a part of the gas discharged from the discharge port 11b of the small compressor 11 is returned to the buffer tank 8. It is configured. The remaining gas is returned to the high-pressure suction line 18 b of the reciprocating compressor 1 through the check valve 17. The shaft seal communication line 9 serves to balance the internal pressures of the cylinder 14 a and the shaft seal 16 of the small compressor 11 and prevent gas leakage from the cylinder 14 a to the shaft seal 16.

  The bypass valve 10a is preferably a globe valve or a diaphragm valve whose opening degree can be adjusted by the action of compressed air or the like. The buffer tank 8 is provided with a tank pressure gauge (tank pressure detecting means) 8a for detecting the gas pressure in the tank 8, and the detected pressure P1 detected by the tank pressure gauge 8a is controlled. It is comprised so that it may input into the device 21a.

  The controller 21a allows the above-described “the amount of vent supplied to the small compressor 11 to be smaller than the processing capacity of the small compressor, that is, the vent amount (gas amount) is too small (the processing capacity of the small compressor 11 is small). It is determined whether or not it is an “excessive” case based on the detected pressure P1. The controller 21a calculates a predetermined opening of the bypass valve 10a according to the input value of the detected pressure P1 so that the value of the detected pressure P1 falls within a predetermined range set in advance. The opening degree of the bypass valve 10a is controlled.

  For example, if the detected pressure P1 is lower than a predetermined pressure value, the controller 21a indicates that “the amount of vent supplied to the small compressor 11 is small, that is, the vent amount (gas amount) is too small (small compressor). 11 is too large). At this time, the degree of opening of the bypass valve 10a is controlled to increase as the difference between the predetermined pressure value and the detected pressure P1 lower than the pressure value increases. If the detected pressure P1 is equal to or higher than a predetermined pressure value, the controller 21a indicates that “the amount of vent supplied to the small compressor 11 is small, that is, the vent amount (gas amount) is too small (small compressor). If the processing capacity of 11 is too large), the bypass valve 10a is closed.

  The bypass valve 10a is preferably a valve whose opening degree can be arbitrarily controlled. However, the present invention is not limited to this, and the bypass valve 10a may be an on-off valve that can be switched to either fully closed or fully open. In that case, it is preferable to control so that the time for opening the bypass valve 10a per predetermined unit time becomes longer as the difference between the predetermined pressure value and the detected pressure P1 lower than the pressure value increases. .

  Further, the detected pressure P1 is determined in advance regardless of whether the bypass valve 10a is a valve whose opening degree can be arbitrarily controlled, or an on-off valve that can be switched to either fully closed or fully opened. It is not always necessary to close the bypass valve 10a when the pressure value is exceeded. For example, when the bypass valve 10a is a valve whose opening degree can be arbitrarily controlled, when the detected pressure P1 is lower than a predetermined pressure value, the larger the pressure difference, the greater the difference of the bypass valve 10a. In contrast, when the detected pressure P1 is higher than a predetermined pressure value, the opening degree of the bypass valve 10a may be reduced as the difference in pressure increases. Moreover, what is called PID control etc. is suitable for control of the opening degree of the bypass valve 10a.

  Further, the small compressor 11 is preferably a hermetic compressor. In the hermetic compressor, the drive motor M2 is housed in the crankcase 12a, and the sealing surface is secured to the joint surface of the crankcase 12a, the cylinder 14a, and the distance piece. Even if the compressed gas in the cylinder 14a leaks, it does not leak outside the distance piece 15 or the crankcase 12a. Alternatively, the same effect can be expected by sealing the crankshaft penetrating portion of the clearance case 12a and making the crankcase 12a and the distance piece 15 have a sealed structure.

  As described above, according to the gas leakage prevention system for a reciprocating compressor according to Embodiment 1 of the present invention, the leakage gas from the shaft seal portion 6 of the reciprocating compressor 1 is recovered and the reciprocating compressor 1 is recovered. A leak gas recovery line 7 is provided to return to the suction side 1a of the gas tank, and a buffer tank 8 connected to the rear end of the vent line 7a forming a part of the leak gas recovery line 7 and a low-pressure suction subsequent to the buffer tank 8 A small compressor 11 connected to the rear end of the line 7b, a shaft seal communicating line 9 for communicating the shaft seal 16 of the small compressor 11 and the low pressure suction line 7b of the small compressor 11, and the buffer A bypass line 10 that communicates the tank 8 and the low-pressure discharge line 7 c and a bypass valve 10 a interposed in the bus pass line 10 are provided.

  The leaked gas stored in the buffer tank 8 is sucked into the small compressor 11 through the low pressure suction line 7b, and after being compressed, is discharged to the low pressure discharge line 7c. When the amount of gas supplied to the compressor 11 is smaller than the processing capacity of the small compressor 11, that is, when the amount of gas is too small (the processing capacity of the small compressor 11 is excessive), the bypass valve 10a is opened. Since a part of the gas discharged from the small compressor 11 is returned to the buffer tank 8 through the bypass line 10, the large reciprocating compressor 1 that is particularly difficult to have a sealed structure. In this case, it is possible to prevent leakage of compressed gas.

  Next, a gas leakage prevention system for a reciprocating compressor according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 2 is a schematic system diagram showing a gas leakage prevention system for a reciprocating compressor according to Embodiment 2 of the present invention as an example of application to a heat pump. However, the difference between the second embodiment of the present invention and the first embodiment is that there is a difference in the configuration of the adjustment mechanism of the gas amount supplied to the small compressor. Since it is the same structure, the same code | symbol is attached | subjected to the same thing as the said Embodiment 1, and the difference is demonstrated below.

  That is, the mechanism for adjusting the amount of gas supplied to the small compressor 11 of the first embodiment includes a bypass line 10 that connects the buffer tank 8 and the low-pressure discharge line 7c, and a bypass that is interposed in the bypass line 10. A valve 10a, a tank pressure gauge 8a for detecting the pressure of the buffer tank 8, and a controller 21a for controlling the opening degree of the bypass valve 10a are provided to the small compressor 11 via the low-pressure suction line 7b. If the vent amount is smaller than the processing capacity of the small compressor 11, that is, the amount of gas supplied from the buffer tank 8 to the small compressor 11 is too small (the processing capacity of the small compressor 11 is excessive), the bypass The bypass valve 10 a interposed in the flow path 10 is opened so that a part of the gas discharged from the discharge port 11 b of the small compressor 11 is returned to the buffer tank 8. It was made.

  In contrast, the mechanism for adjusting the amount of gas supplied to the small compressor 11 according to the second embodiment includes a tank pressure gauge 8a that detects the pressure of the buffer tank 8 and the rotation of the drive motor M2 of the small compressor 11. An inverter 23 for instructing the number, and a controller 24 for calculating and controlling the number of revolutions of the drive motor M2 by a pressure signal detected by the tank pressure gauge 8a. And based on the pressure signal P1 detected by the said tank pressure gauge 8a, it is comprised so that the rotation speed of the drive motor M2 of the said small compressor 11 may be controlled with the frequency signal transmitted to the inverter 23 from the said controller 24. ing.

  As described above, according to the gas leakage prevention system for a reciprocating compressor according to the second embodiment of the present invention, the controller 24 transmits the pressure signal P1 detected by the tank pressure gauge 8a to the inverter 23. Since the rotational speed of the drive motor M2 of the small compressor 11 is controlled by the frequency signal, the small compression that re-pressurizes according to the amount of leaked gas from the shaft seal portion 6a of the reciprocating compressor 1 The load on the machine 11 can be optimized.

  That is, if the detected pressure P1 increases, the rotational speed of the small compressor 11 is increased to increase the processing capacity of the small compressor 11. Conversely, if the detected pressure P1 decreases, the rotational speed of the small compressor 11 is decreased. Thus, the processing capacity of the small compressor 11 is reduced, and control is performed so that the detected pressure P1 falls within a preset range.

  In the embodiment of the present invention, the case where the gas leakage prevention system for a reciprocating compressor according to the present invention is applied to a heat pump as an example has been described. However, the gas leakage of the reciprocating compressor according to the present invention is described. The prevention system is not limited to application to a heat pump in which a circulation line that connects the suction port and the discharge port of the reciprocating compressor is formed. That is, the gas leakage prevention system for a reciprocating compressor according to the present invention is also effective as a gas leakage prevention system for a compressor alone, which compresses the gas sucked from the suction port and supplies it as high pressure gas from the discharge port. .

  In the first embodiment, as shown in FIG. 1, the controllers 21a and 21b are illustrated and described as individual controllers. However, the respective functions may be accommodated in the same controller. Similarly, in the second embodiment, as shown in FIG. 2, the controllers 21b and 24 are illustrated and described as individual controllers. However, the respective functions may be accommodated in the same controller.

It is the typical systematic diagram which showed the gas leakage prevention system of the reciprocating compressor which concerns on Embodiment 1 of this invention as an example which applied the heat pump. It is the typical systematic diagram which showed the gas leakage prevention system of the reciprocating compressor which concerns on Embodiment 2 of this invention as an example which applied the heat pump. It is the whole general | schematic explanatory drawing of the gas compressor which concerns on a prior art example. It is an expanded sectional view of the distance piece shaft seal device of the gas compressor concerning a conventional example. It is explanatory drawing of the standard which concerns on the reciprocating compressor for petroleum, chemical, and gas industries in American Petroleum Institute (API).

Explanation of symbols

M1, M2: drive motor,
P1: Tank detection pressure, P2: Condensation pressure,
1: reciprocating compressor, 11: small compressor,
1a, 11a: suction port, 1b, 11b: discharge port,
2, 12: Crank mechanism, 2a, 12a: Crank case,
3, 13: piston rod,
4, 14: piston, 4a, 14a: cylinder,
5, 15: Distance piece,
6, 16: Shaft seal, 6a, 16a;
7: Leakage gas recovery line, 7a: Vent line,
7b: Low pressure suction line, 7c: Low pressure discharge line,
8: Buffer tank, 8a: Tank pressure gauge (tank pressure detection means),
9: Shaft seal communication line,
10: Bypass line, 10a: Bypass valve,
17: Check valve,
18: Circulation line, 18a: High pressure discharge line, 18b: High pressure suction line,
19: condenser, 20: expansion valve, 21: evaporator,
21a, 21b: controller,
22: Pressure gauge, 23: Inverter, 24: Controller

Claims (5)

A reciprocating compressor;
A leak gas recovery line connecting the shaft seal of the reciprocating compressor and the suction side of the reciprocating compressor;
A buffer tank that is interposed in the leak gas recovery line and stores leak gas leaked from the shaft seal portion of the reciprocating compressor;
A small compressor that is interposed in the leak gas recovery line following the buffer tank and sucks in the leak gas stored in the buffer tank to increase the pressure,
The leak gas is configured to be boosted by the small compressor and then returned to the suction side of the reciprocating compressor via the leak gas recovery line,
A bypass line communicating the buffer tank and a leak gas recovery line on the discharge side of the small compressor;
A bypass valve interposed in the bypass line,
When the amount of gas supplied from the buffer tank to the small compressor is too small, the bypass valve is opened, and part of the gas discharged from the small compressor is transferred to the buffer tank via the bypass line. A gas leakage prevention system for a reciprocating compressor characterized by being configured to return. Tank pressure detecting means for detecting the pressure of the buffer tank,
When the pressure signal detected by the tank pressure detecting means is lower than a predetermined pressure, it is determined that the amount of gas supplied from the buffer tank to the small compressor is too small. The reciprocating compressor gas leakage prevention system according to claim 1, wherein the system is configured to perform the reciprocating compressor. A reciprocating compressor;
A leak gas recovery line connecting the shaft seal of the reciprocating compressor and the suction side of the reciprocating compressor;
A buffer tank that is interposed in the leak gas recovery line and stores leak gas leaked from the shaft seal portion of the reciprocating compressor;
A small compressor that is interposed in the leak gas recovery line following the buffer tank and sucks in the leak gas stored in the buffer tank to increase the pressure,
The leak gas is configured to be boosted by the small compressor and then returned to the suction side of the reciprocating compressor via the leak gas recovery line,
Tank pressure detecting means for detecting the pressure of the buffer tank;
An inverter that commands the rotational speed of the drive motor of the small compressor;
A controller for calculating the number of rotations of the drive motor based on the pressure signal detected by the tank pressure detection means,
A gas leakage prevention system for a reciprocating compressor, wherein the number of revolutions of a drive motor of the small compressor is controlled by a frequency signal transmitted from the controller to an inverter.   The reciprocating compression according to any one of claims 1 to 3, further comprising a shaft seal portion communication line that connects a shaft seal portion of the small compressor and a leakage gas recovery line on the suction side of the small compressor. Machine gas leakage prevention system.   4. The gas leakage prevention system for a reciprocating compressor according to claim 1, wherein the small compressor is a hermetic compressor.

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