JPH07119634A - Reciprocating type compressor - Google Patents

Abstract

PURPOSE:To provide a reciprocating type compressor, in which a piston rod can be efficiently cooled and contamination of compressed gas with a different kind of fluid is eliminated and the whole of which is downsized. CONSTITUTION:Inside of a shaft seal device 21 for cutting off the inside and the outside of a cylinder, a cooling flow passage 28 for communicating a cooling chamber 22, which surrounds the periphery of the piston rod 1 under the condition that it is cut off from any of a compression chamber 3 inside of the cylinder and the outside of the cylinder, with a suction flow passage and a discharge flow passage through a gas cooling unit, a flow quantity control valve, a first and a second pressure control valves is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating compressor having a piston rod cooling structure.

[0002]

2. Description of the Related Art Conventionally, a reciprocating compressor shown in FIGS. 5 and 6 is known (Japanese Utility Model Laid-Open No. 4-116680). This compressor is of a type in which a piston 2 attached to a piston rod 1 reciprocates in a compression chamber 3 in a cylinder. The compression chamber 3 communicates with a suction flow path 5 via a suction valve 4, and It communicates with the discharge flow path 7 via the discharge valve 6. Around the piston rod 1, there is provided a shaft sealing device 8 that shuts off the inside and outside of the compression chamber 3. The shaft sealing device 8 has a plurality of packings 9 arranged in parallel along the axial direction of the piston rod 1. Also, a packing case 10 accommodating these packings 9
A cooling jacket 11 through which cooling water flows is formed in this.

As described above, this compressor has a structure in which the piston 2 is driven by the piston rod 1. Therefore, in order to maintain the airtightness in the compression chamber 3, the shaft sealing device 8 is provided around the piston rod 1. Will be needed. In this case, the surface temperature of the piston rod 1 generates heat due to friction with the shaft sealing device 8, and this heat causes the packing 9 in the shaft sealing device 8 to be thermally deformed.
Since the life of the piston rod 1 is shortened, the cooling rod 11 is provided to cool the piston rod 1.

FIG. 7 shows a piston rod shaft sealing device 8a of the reciprocating compressor disclosed in Japanese Utility Model Laid-Open No. 4-116680 mentioned above. The parts common to the shaft sealing device 8 shown in FIG. 6 are the same. Numbered. The shaft sealing device 8a includes a packing case 10 accommodating a packing 9 and a cooling jacket 11a that surrounds the piston rod 1 in a pressing flange 13 that presses the partition wall 12 of the compression chamber 3.
Is provided. Then, the piston rod 1 is cooled by flowing cooling water or oil into the cooling liquid passage 14 communicating with the cooling jacket 11a.

Besides, a reciprocating compressor shown in FIG. 8 is known (Japanese Patent Publication No. 5-11225). This compressor is
It has a stepped piston rod 15 consisting of a large diameter portion 15L and a small diameter portion 15S, and the piston 2 is attached to the large diameter portion 15L. Further, the sliding space of the large diameter portion 15L is the small diameter portion 15S.
It is a cooling chamber 16 for use with the shaft sealing device 8b provided in the small diameter portion 15S. Then, as shown by the broken line in FIG. 8, the suction passage 17 is formed so as to reach the suction valve 4 after passing through the cooling chamber 16 so that the piston rod 15 is cooled by the low-temperature compressed gas. is there. The compressed gas is compressed in the compression chamber 3 and then discharged to the discharge passage 7 via the discharge valve 6 as in the above.

[0006]

Among the conventional reciprocating compressors shown in FIGS. 5 and 6, the piston rod 15 is used.
Since it is indirectly cooled by the cooling jacket 11, there is a problem that the cooling efficiency is poor and the piston rod 1 cannot be cooled sufficiently. In the case of the reciprocating compressor shown in FIG. 7, since the piston rod 1 is directly cooled by the cooling jacket 11a, the cooling action is strong, but the cooling jacket 11a is used for cooling the piston rod 1. There is a problem that the water or oil may flow into the compression chamber 3 and be mixed with the gas to be compressed.

In the case of the reciprocating compressor shown in FIG. 8, the cooling chamber 1
Even if the length of 6 is the minimum, one stroke of the piston 2 + the width of the seal ring of the large-diameter portion 15L + the width of the gas outlet of the cooling chamber 16 is required. There is a problem that it becomes too long. The present invention is
A reciprocating compressor capable of efficiently cooling the piston rod, eliminating mixing of different fluids into the gas to be compressed, and making the whole compact in view of the conventional problems. It is the one we are trying to provide.

[0008]

In order to solve the above-mentioned problems, a first aspect of the present invention is a state in which a compression chamber inside a cylinder and an outside of the cylinder are shut off in a shaft sealing device that shuts off the inside and outside of the cylinder. Thus, the cooling chamber surrounding the piston rod is formed by providing a cooling flow passage communicating with the suction flow passage and the discharge flow passage through the gas cooler, the flow control valve, the pressure control valve, and the check valve. .

In the second invention, the cooling chamber is an adiabatic expansion space for the gas flowing through the cooling flow passage.

Further, according to a third aspect of the present invention, a cooling chamber, which is a gas adiabatic expansion space that surrounds the piston rod, is provided in a shaft sealing device that shuts off the inside and outside of the cylinder. It was formed by providing a cooling flow path that communicates with the suction flow path and the discharge flow path via a stop valve.

[0011]

With the construction of the first invention, the piston rod is directly cooled by the compressed gas.
According to the second aspect of the invention, the piston rod is directly cooled by the effect of the temperature drop due to the adiabatic expansion of the compressed gas in addition to the effect of the first aspect.
With the configuration according to the third aspect of the invention, the piston rod is directly cooled by the effect of the temperature drop on the adiabatic expansion of the compressed gas.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show a reciprocating compressor according to the first aspect of the present invention. Parts common to the reciprocating compressor shown in FIGS. In the present compressor, a plurality of packings 9 arranged side by side along the axial direction of the piston rod 1 are housed in a shaft sealing device 21 that shuts off the inside and outside of the cylinder. The chamber 22 is connected to the gas cooler 23, the flow rate control valve 24, the first,
A cooling flow passage 28 is formed to communicate with the suction flow passage 5 and the discharge flow passage 7 via the second pressure control valves 25 and 26 and the check valve 27.

The compressed gas branched from the discharge passage 7 is cooled by the gas cooler 23, and the packing case 1
0 is guided to the cooling chamber 22 via the discharge flow passage side portion 28a of the cooling flow passage 28, whereby the piston rod 1 is directly cooled, and then this compressed gas is transferred to the cooling flow passage 28 in the packing case 10. The suction flow path 5 is returned to the suction flow path 5 via the suction flow path side portion 28b. The piston rod 1 is indirectly cooled by the discharge flow passage side portion 28a and the suction flow passage side portion 28b of the cooling flow passage 28.

The flow rate and pressure of the compressed gas returned to the suction passage 5 are controlled by the flow rate adjusting valve 24, the first and second pressure adjusting valves 25 and 26, and the discharge passage side of the cooling passage 28, the portion 28a. A differential pressure is constantly generated between the suction passage side portion 28b and the suction flow passage side portion 28b, and a desired flow rate of the compressed gas flows in the cooling chamber 22. Further, the check valve 27 prevents the backflow of the compressed gas from the suction passage 5. In order to block the cooling chamber 22 and the compression chamber 3 on the left side in FIG. 2 and the outside of the cylinder on the right side, it is necessary to provide packings 9 on the left and right sides of the cooling chamber 22.

As described above, in this compressor, the piston rod 1 is directly cooled by the compressed gas cooled by the gas cooler 23, so that the piston rod 1 can be efficiently cooled and different from the compressed gas. It is designed to eliminate the mixture of fluids (water, oil, different gases, etc.). In addition, since the cooling chamber 22 is formed in the shaft sealing device 21, compared with the case of the reciprocating compressor shown in FIGS.
It is not necessary to make the piston rod 1 too long (only the width of the cooling chamber 22 becomes longer), and the entire compressor is compact.

FIG. 3 shows a shaft seal device 21a of a reciprocating compressor according to the second invention and a portion in the vicinity thereof. The reciprocating compressor shown in FIGS. Is substantially the same except that it is replaced with the cooling chamber 22a that adiabatically expands, and common parts are denoted by the same reference numerals and description thereof is omitted. In the present compressor, the first and second pressure control valves 25 and 26 are used to adjust the differential pressure before and after the cooling chamber 22a to adiabatically expand the compressed gas in the cooling chamber 22a. . As a result, in addition to the function of the first invention, the adiabatic expansion of the compressed gas in the cooling chamber 22a is directly affected by the temperature drop on the piston rod 1. As a result, the piston rod 1 is It will be cooled more efficiently. .

FIG. 4 shows the shaft seal device 21b of the reciprocating compressor according to the third aspect of the present invention and the portion in the vicinity thereof. The reciprocating compressor shown in FIG. 3 does not include the gas cooler 23. Except for the above, the other parts are substantially the same, and common parts are denoted by the same reference numerals and description thereof is omitted. And
The present compressor directly cools the piston rod 1 only by adiabatically expanding the compressed gas from the cooling flow passage 28a in the cooling chamber 22a. In the case of this device,
Although the compressed gas is not cooled by the gas cooler 23 as in the first and second aspects of the invention, it is the same as the above with respect to the prevention of mixing of different fluids into the compressed gas and the compaction of the entire compressor.

[0018]

As is apparent from the above description, according to the first aspect of the invention, in the shaft sealing device that shuts off the inside and outside of the cylinder, both the compression chamber inside the cylinder and the outside of the cylinder are shut off. , The cooling chamber surrounding the piston rod,
It is formed by providing a cooling flow path communicating with the suction flow path and the discharge flow path through the gas cooler, the flow rate control valve, the pressure control valve, and the check valve. For this reason, the compressed gas directly cools the piston rod, efficiently cools the piston rod, eliminates mixing of different fluids into the compressed gas, and makes the whole compact. Has the effect. Further, according to the second aspect of the invention, the cooling chamber is an adiabatic expansion space for the gas flowing through the cooling flow path.

Therefore, in addition to the effects of the first invention,
The adiabatic expansion of the compressed gas also has the effect of lowering the temperature, so that the piston rod can be further cooled directly. Further, according to the third aspect of the invention, in the shaft sealing device that shuts off the inside and the outside of the cylinder, the cooling chamber, which is the gas adiabatic expansion space surrounding the piston rod, is provided with the flow control valve, the pressure control valve, and the check valve. It is formed by providing a cooling flow path communicating with the suction flow path and the discharge flow path via a valve. For this reason, the adiabatic expansion of the compressed gas causes a temperature drop to directly cool the piston rod, efficiently cool the piston rod, eliminate mixing of different fluids into the compressed gas, and The effect that it becomes possible to make the compact.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a reciprocating compressor according to a first invention.

FIG. 2 is a cross-sectional view showing a shaft sealing device portion of the compressor shown in FIG.

FIG. 3 is a sectional view of a shaft sealing device portion of a reciprocating compressor according to a second invention.

FIG. 4 is a sectional view of a shaft sealing device portion of a reciprocating compressor according to a third invention.

FIG. 5 is a diagram showing an outline of a conventional reciprocating compressor.

6 is a cross-sectional view showing a shaft sealing device portion of the compressor shown in FIG.

FIG. 7 is a sectional view of a shaft sealing device portion of another conventional reciprocating compressor.

FIG. 8 is a sectional view of a shaft sealing device portion of another conventional reciprocating compressor.

[Explanation of symbols]

1 Piston Rod 3 Compression Chamber 5 Suction Flow Path 7 Discharge Flow Path 21, 21a, 21b Shaft Sealing Device 22, 22a
Cooling chamber 23 Gas cooler 24 Flow rate control valve 25 First pressure control valve 26 Second pressure control valve 27 Check valve 28, 28a
Cooling channel

Claims (3)

[Claims] 1. A cooling chamber that surrounds a piston rod in a shaft sealing device that shuts off the inside and outside of the cylinder, in a state where both the compression chamber inside the cylinder and the outside of the cylinder are shut off,
A reciprocating compressor characterized in that a reciprocating compressor is formed by providing a cooling flow path communicating with a suction flow path and a discharge flow path via a gas cooler, a flow rate control valve, a pressure control valve, and a check valve. 2. The reciprocating compressor according to claim 1, wherein the cooling chamber is an adiabatic expansion space for gas flowing through the cooling flow path. 3. A cooling chamber, which is a gas adiabatic expansion space that surrounds the piston rod, in a state where both the compression chamber inside the cylinder and the outside of the cylinder are blocked in the shaft sealing device that blocks the inside and outside of the cylinder. Is provided with a cooling flow passage communicating with the suction flow passage and the discharge flow passage through the flow rate control valve, the pressure control valve, and the check valve.