JP2004293480A - Semi-sealed compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semi-sealed compressor capable of making compression to a higher pressure than conventional, embodied in a simple structure, and assuring excellent durability and a high reliability. <P>SOLUTION: The semi-sealed compressor 1 of multistage compression type is structured so that a gas compressed by a lower stage cylinder 5 is sent to an upper stage cylinder 6 through a pipe 40 to be compressed further to generate a high pressure, wherein the diameter of the upper stage cylinder 6 is formed greater than the diameter of the lower stage cylinder 5 so as to reduce the shaft load, and the capacity efficiency is enhanced by cooling the gas compressed by the lower stage cylinder 5 when it passes through the pipe 40. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semi-hermetic compressor used in various industrial fields such as a refrigerator, a heating / cooling device, a semiconductor manufacturing apparatus, and a coating machine, and particularly to a multi-stage compressible semi-hermetic compressor suitable for compressing a CO ₂ refrigerant. .
[0002]
[Prior art]
FIG. 4 is a view for explaining a conventional semi-hermetic compressor, FIG. 4 (a) is a view showing an outline thereof, and FIG. 4 (b) is a view for explaining details thereof. The semi-hermetic compressor 44 is a two-cylinder type having two cylinders 45 in a semi-hermetic housing 49, and a cylinder head that forms a suction chamber 47 and a discharge chamber 48 common to the two cylinders 45 on the upper part thereof. 46 are provided.
[0003]
The semi-hermetic compressor 44 includes a crank portion 51 driven by a motor 50 in a housing 49. By rotation of the crank portion 51, two sets of a connecting rod 52 and a piston 53 corresponding to the two cylinders 45 are provided. The reciprocating mechanism performs a reciprocating operation with a phase difference of 180 degrees from each other. Thus, the two cylinders 45 share the suction chamber 47 and the discharge chamber 48, but perform the gas compression operation independently of each other.
[0004]
More specifically, the gas sucked into the semi-hermetic compressor 44 flows into the suction chamber 47, opens the suction valve 59 from the suction port 58, and is sucked into the cylinder 45. The gas compressed by the piston 53 in the cylinder 45 opens the discharge valve 55 from the discharge port 54, flows into the discharge chamber 48, and is sent to the discharge part 57 of the semi-hermetic compressor 44 through the discharge passage 56, From there, the compressed gas (refrigerant) is sent to the required equipment that requires it.
[0005]
A reciprocating compressor having a plurality of cylinders of the same type as the conventional example is known (for example, see Patent Document 1). Further, a configuration in which two-stage compression is performed by a rotary-type compressor is known (see Patent Document 2).
[0006]
[Patent Document 1]
JP-A-5-215073 (FIG. 1)
[Patent Document 2]
JP-A-5-256285 (FIG. 1)
[0007]
[Problems to be solved by the invention]
By the way, in the conventional semi-hermetic compressor 44, the two sets of connecting rods 52 and pistons 53 corresponding to the two cylinders 45 reciprocate with a phase difference of 180 degrees from each other, and the suction chamber 47 and the discharge chamber 48 are common. However, since each of them independently compresses gas, there are the following problems.
[0008]
That is, when a plurality of cylinders have the same equipment for a piston seal, a connecting rod, and the like, there is a limit to a single cylinder that can compress gas to a predetermined high pressure at once. For example, when the pressure is set to a predetermined high pressure at once, even if the piston is sealed with the piston seal, the refrigerant is likely to leak to the crank chamber side, and the leak amount may increase. Also, the load (axial load) on mechanical parts such as the connecting rod increases.
[0009]
In recent years, there has been a demand for a large-volume, high-pressure compressor. However, in a compressor having a plurality of cylinders (a multi-cylinder compressor) as described above, the cylinders independently perform a compression operation. Although it is easy to send out the compressed gas, there is a limit in the driving capability because a plurality of cylinders are provided for one drive mechanism, and there is also a limit in that the mechanism and arrangement of the cylinders and the like become complicated.
[0010]
In particular, it is not appropriate when the refrigerant is compressed to a relatively high pressure state, for example, when the CO ₂ refrigerant is compressed to a high pressure (for example, 31 Mpa) for use in a supercritical region.
[0011]
The rotary-type compressor disclosed in Patent Document 2 is not suitable for handling a larger-capacity refrigerant than a reciprocating compressor.
[0012]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the conventional compressor, and can perform higher-pressure compression, and has a simple structure, excellent durability, and high reliability. This realizes a semi-hermetic compressor capable of high multistage compression.
[0013]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a low-stage cylinder and a high-stage cylinder, and cylinders provided on the two cylinders to define a suction chamber and a discharge chamber corresponding to each of the two cylinders. A head, a low-stage piston that reciprocates in the low-stage cylinder, and a high-stage piston that reciprocates in the high-stage cylinder. A multi-stage compressor capable of multi-stage compression to further increase the pressure by compressing with a side cylinder, wherein the diameter of the low-stage cylinder is formed larger than the diameter of the high-stage cylinder. Provide a possible semi-hermetic compressor.
[0014]
In order to solve the above-described problems, the present invention provides a low-stage cylinder and a high-stage cylinder, and cylinders provided on the two cylinders to define a suction chamber and a discharge chamber corresponding to each of the two cylinders. A head, a low-stage piston that reciprocates in the low-stage cylinder, and a high-stage piston that reciprocates in the high-stage cylinder. A multi-stage compressible semi-hermetic compressor that further compresses to a higher pressure by a side cylinder, and sends gas compressed by the low-stage cylinder through a pipe to the high-stage cylinder, wherein the pipe is Provided is a multi-stage compressible semi-hermetic compressor, which is configured to cool a compressed gas.
[0015]
Further, the present invention, in order to solve the above problems, a plurality of cylinders, provided on the plurality of cylinders, a cylinder head that defines a suction chamber and a discharge chamber corresponding to each of the plurality of cylinders, A plurality of pistons reciprocating in each of the plurality of cylinders, a multi-stage compressible semi-hermetic compressor for compressing the sucked gas to a high pressure stepwise by the plurality of cylinders and pistons, The diameter of each of the cylinders is formed smaller corresponding to the cylinder that compresses the inhaled gas to a higher pressure, and the plurality of cylinders are each connected to another cylinder for compressing to a higher pressure through a pipe. The pipe is provided to cool the compressed gas, thereby providing a multi-stage compressible semi-hermetic compressor.
[0016]
The gas is a CO ₂ refrigerant.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a multi-stage compressible semi-hermetic compressor according to the present invention will be described below based on examples with reference to the drawings. FIG. 1 is an overall view (front sectional view) of an embodiment of a semi-hermetic compressor, FIG. 2 is a partial cross-sectional view of the embodiment of the semi-hermetic compressor as viewed from the side, and FIG. FIG. 4 is an explanatory plan view for explaining the flow of gas in the head cylinder section. In the following embodiments, the compressed gas will be described as a refrigerant used in a refrigerator, an air conditioner, and the like.
[0018]
The semi-hermetic compressor 1 is a two-cylinder compressor having a low-stage cylinder 5 and a high-stage cylinder 6, and has a housing 2 made of a casting. In the housing 2, a motor chamber 3, a crank chamber 4, a low-stage cylinder 5, and a high-stage cylinder 6 are defined.
[0019]
The motor chamber 3 and the crank chamber 4 are formed with openings necessary for parts loading and maintenance, and the like, and these openings are closed by lids 7 and 8, respectively. The motor room 3 is provided with a motor (such as a three-phase induction motor) 9. A crankshaft 10 is fixed to an output shaft of the motor 9.
[0020]
The crankshaft 10 is supported by bearings 11 and 12 and is rotatably arranged. The crankshaft 10 is formed with a low-stage crank portion 13 and a high-stage crank portion 14 that convert the rotation of the motor 9 into reciprocating motion. A low-stage piston 17 and a high-stage piston 18 are attached to the low-stage crank portion 13 and the high-stage crank portion 14 via a low-stage connecting rod 15 and a high-stage connecting rod 16 so as to interlock. I have.
[0021]
The low-stage piston 17 and the high-stage piston 18 are disposed so as to be able to reciprocate in the low-stage cylinder 5 and the high-stage cylinder 6. A cylinder head 21 is fixed to a top surface of an upper portion 19 of the housing 2 constituting the low-stage cylinder 5 and the high-stage cylinder 6 with a bolt 22 via a valve plate 20.
[0022]
By the way, in the case of the internal low pressure, the pressure difference between the high-stage cylinder 6 and the crank chamber becomes higher than that of the low-stage cylinder 5, so that if the low-stage cylinder 5 and the high-stage cylinder 6 have the same cylinder diameter, The axial load (load applied to the piston and the connecting rod) in the stage side cylinder 6 becomes larger than that in the lower stage side. In order to solve this problem, in the present invention, the diameter of the high-stage cylinder 6 is made smaller than the diameter of the low-stage cylinder 5. Thereby, the load applied to the piston 18 and the connecting rod 16 on the high-stage side can be reduced. In the case of the internal medium pressure system, in addition to the load (torque) in the compression process on the high stage side, the discharge pressure on the low stage side and the pressure in the crank chamber are almost the same, so a large load (torque) on the suction process in the low stage Is over. Conversely, the load (torque) in the compression step on the low-stage side and the suction step on the high-stage side decreases, and the torque fluctuation increases. By reducing the bore on the high-stage side, the load in the compression step on the high-stage side can be reduced, and torque fluctuation can be reduced.
[0023]
The space formed by the cylinder head 21 is partitioned by a substantially cross-shaped partition wall 25, and a lower-stage suction chamber 23, a lower-stage discharge chamber 24, a higher-stage suction chamber 26, and a higher-stage discharge chamber 27 are defined. It is defined. An outlet 28 of the lower-stage discharge chamber 24 and an inlet 29 of the higher-stage suction chamber 26 are connected by a pipe 40 so as to communicate with each other.
[0024]
The refrigerant compressed by the low-stage cylinder 5 and raised to a certain pressure (hereinafter referred to as “medium pressure” for convenience) is further compressed by the high-stage cylinder 6 to a predetermined high pressure.
[0025]
The valve plate 20 is formed with a low-stage suction port 30 for communicating the low-stage suction chamber 23 and the low-stage cylinder 5 with each other, and connects the low-stage discharge chamber 24 and the low-stage cylinder 5 to each other. A low-stage discharge port 31 communicating with each other is formed.
[0026]
Further, the valve plate 20 is formed with a high-stage suction port 32 for communicating the high-stage suction chamber 26 and the high-stage cylinder 6 with each other. Is formed in a high-stage discharge port 33 that communicates with the other.
[0027]
A low-stage suction valve and a high-stage suction valve (not shown) are provided on the lower surface of the valve plate 20 with respect to the low-stage suction port 30 and the high-stage suction port 32. For the low-stage discharge port 31 and the high-stage discharge port 33, a low-stage discharge valve 31 'and a high-stage discharge valve 33' are provided on the upper surface of the valve plate 20, respectively. These valves are normally closed valves urged by a spring so as to be normally closed, but the low-stage discharge valve 31 ′ has the above-mentioned intermediate pressure, and the high-stage discharge valve 33 ′ has a predetermined high pressure. , Each is a normally closed valve that opens.
[0028]
The valve plate 20 is provided with a suction port 41 for sucking refrigerant from a compression refrigerant utilization device (not shown) into the low-stage suction chamber 23. Further, the valve plate 21 is provided with a discharge port 42 for discharging the refrigerant toward the compressed refrigerant utilization device.
[0029]
In FIG. 2, a suction portion 35 for sucking refrigerant is formed in a rear portion (left portion in FIG. 2) 34 of the housing 2 and is connected to the compressed refrigerant utilization device via a connection pipe (not shown). The suction portion 35 is configured to communicate with a suction port 41 through a suction passage 36 formed in the housing 2. The suction portion 35 is provided with a filter 37 having a mesh so as to be inserted into the suction passage 36.
[0030]
A discharge portion 39 for discharging the refrigerant compressed by the high-stage cylinder 6 to the outside of the hermetic compressor 1 is formed in a front portion (right portion in FIG. 2) 38 of the housing 2. Reference numeral 39 is configured to communicate with the discharge port 42 through a discharge passage (not shown) formed in the housing 2.
[0031]
In the semi-hermetic compressor 1 capable of multi-stage compression according to the present invention, the outlet 28 of the lower-stage discharge chamber 24 and the inlet 29 of the higher-stage suction chamber 26 are connected by a pipe 40. The pipe 40 supplies the refrigerant compressed by the low-stage cylinder 5 and discharged from the outlet 28 of the low-stage discharge chamber 24 to the inlet 29 of the high-stage suction chamber 26, and cools the refrigerant to cool the refrigerant. The concentration can be increased and the volume efficiency can be improved.
[0032]
In order to cool the refrigerant, the refrigerant may be naturally cooled by air cooling while passing through the pipe 40 without specially working the pipe 40, or the cooling may be performed on the outer surface of the pipe 40. Fins or the like may be attached. Further, a configuration may be adopted in which a coolant that passes through the inside of the pipe 40 is actively cooled as a water cooling structure in which the pipe 40 is passed through, for example, circulating cooling water.
[0033]
(Action)
The operation of the above embodiment of the multi-stage compressible semi-hermetic compressor 1 according to the present invention having the above configuration will be described. Hereinafter, the operation will be described using a refrigerant such as a CO ₂ refrigerant as the gas to be compressed. Actually, the refrigerant flowing from the suction part 35 is a gas-liquid mixed state, and the refrigerant containing a little oil flows.
[0034]
The motor 9 rotates the crankshaft 10 in the forward direction, and the low-stage crank portion 13 and the high-stage crank portion 14 in the crank chamber 4 rotate with a phase shift of about 180 ° from each other. As a result, the low-stage piston 17 and the high-stage piston 18 reciprocate with a phase difference of about 180 ° from each other.
[0035]
The low-stage piston 17 moves ahead by about 180 degrees in the low-stage cylinder 5 toward the top dead center, and compresses the refrigerant in the upper space of the low-stage cylinder 5. Then, when the compressed refrigerant reaches a preset pressure (medium pressure), the low-stage discharge valve 31 ′ of the low-stage cylinder 5 opens, and the low-stage discharge chamber 24 or the outlet 28 into the pipe 40. Discharge.
[0036]
The refrigerant passes through the pipe 40, enters the high-stage suction chamber 26 from the inlet 29, and further flows into the high-stage cylinder 6 from the suction port 32. Then, the refrigerant is compressed in the high-stage cylinder 6 by the high-stage piston 18 that moves with a phase difference of 180 ° behind the low-stage piston 17, and has a higher pressure. When the compressed gas is compressed in the high-stage side cylinder 6 and reaches a predetermined high pressure, the high-stage discharge valve 33 ′ is pushed open, and the high-stage discharge port 33 is connected to the high-stage discharge chamber 27 and the discharge port 42. Through the discharge section 39 to the compressed refrigerant utilization device.
[0037]
As described above, in the present invention, the refrigerant is compressed to the medium pressure on the low stage, further compressed to the high stage, and gradually compressed to the predetermined high pressure in two stages. Therefore, the compression to the middle pressure may be performed at the lower stage, and the axial load applied to the compression lower stage piston 17 and its crankshaft 15 is reduced. On the other hand, since the cylinder diameter of the high-stage cylinder 6 is smaller than that of the low-stage cylinder 5, the axial load applied to the high-stage piston 18 and the crankshaft 16 is reduced.
[0038]
With the conventional configuration in which the refrigerant is compressed to a high pressure all at once, there is a problem that the refrigerant leaks from the space between the cylinder and the piston seal to the crank chamber 4 side. However, in the present invention, the refrigerant is gradually reduced in two stages. Such a problem can be solved by compressing to a predetermined high pressure.
[0039]
When the refrigerant passes through the pipe 40, it is cooled by air cooling (or water cooling), so that the volume decreases and the concentration increases, thereby increasing the volume efficiency.
[0040]
In the above embodiment, a two-cylinder semi-hermetic compressor provided with two cylinders has been described. However, the present invention can be applied to a three or more multi-cylinder type (multi-stage type) or a semi-hermetic compressor. Even in a multi-cylinder type of three or more (multi-stage type), if the diameter of the cylinder that compresses the refrigerant to a higher pressure is further reduced, the axial load is reduced.
[0041]
Although the embodiment of the semi-hermetic compressor capable of multi-stage compression according to the present invention has been specifically described based on the embodiments, the present invention embodies the technical idea within the scope described in the claims. Needless to say, the present invention is not limited to the above-described embodiment, but includes various embodiments.
[0042]
【The invention's effect】
According to the semi-hermetic compressor of the present invention having the above configuration, the following effects are produced.
(1) It is possible to realize a semi-hermetic compressor having a simple structure, capable of compressing at a higher pressure, and having excellent durability and high reliability.
(2) It is possible to solve the problem that the refrigerant, which tends to be generated when the refrigerant is compressed to a high pressure at a stroke, leaks to the crank chamber side from between the cylinder and the piston seal.
(3) Since the refrigerant is cooled (air-cooled or water-cooled) when passing through the pipe, the volume is reduced and the concentration is increased, thereby increasing the volume efficiency.
(4) By gradually increasing the pressure with a plurality of cylinders, the load (axial load) on mechanical parts such as connecting rods is reduced.
[Brief description of the drawings]
FIG. 1 is an overall view showing an embodiment of a semi-hermetic compressor according to the present invention.
FIG. 2 is a partial cross-sectional view of an embodiment of the semi-hermetic compressor according to the present invention as viewed from the side.
FIG. 3 is a diagram illustrating a characteristic configuration of a semi-hermetic compressor according to the present invention.
FIG. 4 is a diagram illustrating a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Semi-hermetic compressor 2, 49 Housing 3 Motor room 4 Crank room 5 Low stage cylinder 6 High stage cylinder 7, 8 Lid 9, 50 Motor 10 Crank shaft 11, 12 Bearing 13 Low stage crank part 14 High stage side Crank part 15 Low-stage connecting rod 16 High-stage connecting rod 17 Low-stage piston 18 High-stage piston 19 Upper part of housing 20 Valve plate 21, 46 Cylinder head 22 Bolt 23 Low-stage suction chamber 24 Low-stage discharge Chamber 25 partition wall 26 high-stage suction chamber 27 high-stage discharge chamber 28 low-stage discharge chamber outlet 29 high-stage suction chamber inlet 30 low-stage suction port 31 low-stage discharge port 31 'low-stage discharge valve 32 High-stage suction port 33 High-stage discharge port 33 'High-stage discharge valve 34 Rear part of housing 35 Suction part 36 Suction passage 37 Filter 38 House Front section 39 discharge section 40 pipe 41, 58 suction port 42, 54 discharge port 44 conventional semi-hermetic compressor 45 cylinder 47 suction chamber 48 discharge chamber 51 crank section 52 connecting rod 53 piston 55 discharge valve 56 discharge passage 57 discharge section

Claims (4)

A low-stage cylinder and a high-stage cylinder, a cylinder head provided on the two cylinders and defining a suction chamber and a discharge chamber corresponding to each of the two cylinders, and reciprocating in the low-stage cylinder A low-stage piston that moves, and a high-stage piston that reciprocates in the high-stage cylinder. The gas compressed by the low-stage cylinder is further compressed by the high-stage cylinder to a higher pressure. A multi-stage compressible semi-hermetic compressor,
A semi-hermetic compressor capable of multi-stage compression, wherein a diameter of the low-stage cylinder is larger than a diameter of the high-stage cylinder. A low-stage cylinder and a high-stage cylinder, a cylinder head provided on the two cylinders and defining a suction chamber and a discharge chamber corresponding to each of the two cylinders, and reciprocating in the low-stage cylinder A low-stage piston that moves, and a high-stage piston that reciprocates in the high-stage cylinder. The gas compressed by the low-stage cylinder is further compressed by the high-stage cylinder to a higher pressure. A multi-stage compressible semi-hermetic compressor,
Multistage compressible semi-hermetic compressor characterized in that the gas compressed by the low-stage cylinder is fed to the high-stage cylinder through a pipe, and the pipe is configured to cool the compressed gas. . A plurality of cylinders, a cylinder head provided on the plurality of cylinders and defining a suction chamber and a discharge chamber corresponding to each of the plurality of cylinders, and a plurality of pistons reciprocating in each of the plurality of cylinders With a plurality of cylinders and pistons, a multi-stage compressible semi-hermetic compressor that compresses the sucked gas to a high pressure step by step,
The diameter of each of the plurality of cylinders is formed smaller corresponding to the cylinder that compresses the sucked gas to a higher pressure,
The plurality of cylinders are each fed through a pipe to another cylinder for compressing to a higher pressure, and the pipe is configured to cool the compressed gas. Hermetic compressor. 4. The multi-stage compressible semi-hermetic compressor according to claim 1, wherein the gas is a CO ₂ refrigerant.

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