JP2004162645A - Compressor and compression heat pump system having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compressor 2 in which extremely high pressure natural operating medium X in a main body 23 of the compressor 2 is prevented from flowing out of between a drive shaft 21 and the main body 23 to the atmosphere or the like, even in a compression heat pump system using natural operating medium such as carbon dioxide to be compressed into extremely high pressure. <P>SOLUTION: A plurality of shaft seal parts S1, S2 are disposed in a shaft space 29 between the drive shaft 21 and the main body 23, and along the drive shaft 21 to be in parallel with each other. Fluid sealant Y is supplied to a fluid sealant space 28 formed between the plurality of shaft seal parts S1, S2 in the shaft space 29. A fluid sealant supply means A is provided for setting the fluid sealant space 28 to be lower than discharge pressure of compressed fluid X and higher than pressure outside of the main body 23. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is configured such that a fluid to be compressed can be compressed by rotational driving of a compression rotor housed in a main body, and one end of a drive shaft of the compression rotor is connected to an external rotation drive source as a connecting portion. The present invention relates to a compressor exposed outside a main body and a compression heat pump system including the same.
[0002]
[Prior art]
A conventional compression heat pump system that uses an artificial working medium such as chlorofluorocarbon as a working medium compresses a working medium in a gaseous phase with a compressor, then radiates heat with a radiator and cools the working medium into a liquid phase. The liquid is decompressed by an expansion valve and then evaporated by a heat absorber to remove the latent heat of evaporation from the atmosphere to form a gaseous state. By utilizing the heat absorption / radiation at the time of the change, the heat is forcibly moved from the heat absorber to the radiator side.
[0003]
In recent years, from the viewpoint of protection of the ozone layer and prevention of global warming, application of a natural working medium such as carbon dioxide as an operating medium of a compression heat pump system, instead of an artificial working medium such as chlorofluorocarbon, has been attracting attention. A compression heat pump system using such carbon dioxide as a working medium has been put to practical use.
[0004]
Since the critical point temperature of carbon dioxide as such a natural working medium is lower than that of an artificial working medium such as chlorofluorocarbon, when the outside air temperature is high, for example, in summer, the temperature of carbon dioxide in the radiator increases the critical point of carbon dioxide. The temperature may be higher than the temperature, and carbon dioxide may not be in a liquid phase state in the radiator.
Therefore, in a compression heat pump system using a natural working medium such as carbon dioxide, the operating pressure of the compressor (discharge pressure of the working medium) may be set to an extremely high level of about 10 MPa in order to exhibit sufficient performance.
[0005]
On the other hand, when the rotation drive source of the compressor of the compression heat pump system is an external rotation drive source such as an engine installed outside, the compressor is used as a drive shaft for rotating a compression rotor for compression. It is necessary to configure the external drive type compressor with the connection part exposed outside the main body, and between the drive shaft and the main body, the working medium flows out from the compression rotor side inside the main body along the drive shaft. A shaft seal portion such as a known mechanical seal or the like for preventing the above-mentioned operation is provided.
[0006]
[Problems to be solved by the invention]
In a compression heat pump system using an artificial working medium such as chlorofluorocarbon, the operating pressure is relatively low at about 3 MPa. Therefore, the outflow of the working medium can be easily suppressed by providing the aforementioned shaft seal portion. In a compression heat pump system using a natural working medium such as the one described above, the operating pressure is as high as about 10 MPa, so it is difficult to sufficiently prevent the working medium from flowing out by simply providing the shaft seal. is there.
[0007]
Therefore, in view of the above circumstances, the present invention provides a compression type heat pump system using a natural working medium such as carbon dioxide which needs to be compressed to a very high pressure. It is an object of the present invention to realize a compressor that can favorably prevent a medium from flowing into the atmosphere or the like from between a drive shaft and a compressor body.
[0008]
[Means for Solving the Problems]
A first characteristic configuration of the compressor according to the present invention for achieving this object is, as described in claim 1 of the claims, by the rotational drive of the compression rotor housed in the main body. The compressor is configured to be able to compress, one end of the drive shaft of the compression rotor is exposed outside the main body as a connection portion connected to an external rotation drive source,
A plurality of shaft seals are arranged in a shaft space between the drive shaft and the main body along the drive shaft, and
A sealing fluid is supplied to a sealing fluid space formed between the plurality of shaft seal portions of the shaft space, and a pressure of the sealing fluid space is lower than a discharge pressure of the fluid to be compressed and outside the main body. And a sealing fluid supply means for setting the set pressure higher than the set pressure.
[0009]
That is, according to the compressor having the first characteristic configuration, by providing the sealing fluid supply means, a shaft such as a mechanical seal disposed along the drive shaft on the side of the compression rotor with respect to the sealing fluid space. In the seal portion, the fluid to be compressed having the highest discharge pressure existing on the side of the compression rotor is supplied with a sealing fluid having a set pressure lower than the discharge pressure and higher than the external pressure such as the atmospheric pressure. What is necessary is just to suppress outflow to the fluid space. Further, in a shaft seal portion such as a mechanical seal disposed closer to the connecting portion than the sealing fluid space along the drive shaft, the sealing fluid at the set pressure is applied at an atmospheric pressure lower than the set pressure. What is necessary is just a thing which suppresses outflow to a certain main body. Therefore, each of the shaft seal portions is provided with a simple pressure-suppressing device that suppresses the outflow of the fluid to be compressed and the sealing fluid under a pressure difference sufficiently smaller than the pressure difference between the discharge pressure of the fluid to be compressed and the pressure outside the main body. For example, even if the discharge pressure of the fluid to be compressed is extremely high, the differential pressure at each shaft seal portion is small, so that the outflow of the fluid to be compressed and the sealing fluid can be sufficiently performed at each shaft seal portion. Can be suppressed.
[0010]
Therefore, even when used as a compressor for a compression heat pump system using a natural working medium such as carbon dioxide, the working medium, which is a high-pressure compressed fluid in the main body, flows out from between the drive shaft and the main body to the atmosphere or the like. Thus, it is possible to realize a compressor capable of favorably suppressing the operation of the compressor.
[0011]
Also, since a small amount of the sealing fluid may flow out of the main body along the drive shaft from the sealing fluid space via the shaft seal portion closer to the connecting portion than the sealing fluid space. The sealing fluid is preferably a fluid having no problem even if it flows out to the atmosphere. For example, it is preferable to use air, nitrogen, water or the like as the sealing fluid.
[0012]
The second characteristic configuration of the compressor according to the present invention is, as described in claim 2 in the claims section, in addition to the first characteristic configuration, wherein the sealing fluid supply unit includes the external rotation drive source. It is characterized in that it comprises a compression means for compressing the sealing fluid supplied to the sealing fluid space by utilizing a part of the rotational driving force.
[0013]
That is, according to the compressor having the second characteristic configuration, the sealing fluid supply unit converts the sealing fluid compressed by the compression unit using a part of the power of an external drive source such as the engine into the sealing fluid. By supplying the pressure to the space, the pressure of the sealing fluid space can always be maintained at a set pressure higher than the pressure outside the main body such as the atmospheric pressure, and the pressure is more compressed along the drive shaft than the sealing fluid space. The differential pressure in the shaft seal portion on the rotor side is always kept small, so that the outflow of the compressed fluid into the sealed fluid space can be suppressed well.
Further, by providing the compression means, it is not necessary to provide a pressure accumulating section for accumulating and storing the sealing fluid, and it is possible to save the trouble of replenishing the sealing fluid at the set pressure.
[0014]
A third characteristic configuration of the compressor according to the present invention is that, in addition to the first and second characteristic configurations, the compressed fluid is carbon dioxide, as described in claim 3 of the claims. is there.
[0015]
That is, according to the compressor having the third characteristic configuration, even if the compressor is configured to compress carbon dioxide as the fluid to be compressed, the carbon dioxide is supplied to the outside of the main body along the drive shaft by the sealing fluid supply unit. Can be satisfactorily suppressed, and the discharge pressure can be set very high.
[0016]
In order to achieve this object, the characteristic structure of the compression heat pump system according to the present invention is a compressor for compressing a working medium in a compression heat pump as the fluid to be compressed, as described in claim 4 of the claims. Another aspect of the present invention is to provide a compressor having the first to third characteristic configurations.
[0017]
That is, according to the compression heat pump system having the above-described configuration, even if a natural working medium such as carbon dioxide, which needs to be compressed to a very high pressure, is used, the sealed fluid supply means of the compressor can cover the inside of the compressor body. It is possible to realize a compression heat pump system capable of favorably suppressing the natural working medium, which is a compressed fluid, from flowing out of the main body.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings.
As is well known, the compression heat pump system 100 shown in FIG. 1 is configured such that the working medium X circulates through the compressors 2, 20, the radiator 3, the expansion valve 4, and the heat absorber 5 in the stated order. , The working medium X absorbs heat, and the working medium X radiates heat in the radiator 3.
[0019]
Here, the heat absorption target in the heat absorber 5 is assumed to be the atmosphere, and a gas-liquid heat exchanger is adopted as the heat absorber 5. The heating target of the radiator 3 is hot water for hot water supply, and the radiator 3 employs a liquid-liquid heat exchanger.
[0020]
The working medium X is carbon dioxide as a natural working medium.
A state of each device will be described. In a working medium flow path 7 composed of a pipe connected from the heat absorber 5 to the compressors 2 and 20, a working medium X having a temperature of about 4 ° C. and a pressure of about 4 MPa flows. Then, in the working medium flow path 8 composed of a tube connected from the compressors 2 and 20 to the radiator 3, the working medium X having a temperature of about 80 ° C. and a pressure of about 9.0 to 10 MPa flows, and the heat is radiated. A working medium X having a temperature of about 4 ° C. and a pressure of about 9.0 to 10 MPa flows through a working medium flow path 9 composed of a pipe connected from the vessel 3 to the expansion valve 4, and receives heat from the expansion valve 4. The working pressure of the compressors 2 and 20 (the working medium X) is set so that the working medium X having a temperature of about 4 ° C. and a pressure of about 4 MPa flows through the working medium flow path 10 composed of a tube connected to the vessel 5. Discharge pressure ) And the set differential pressure or the like of the expansion valve 4 is set.
[0021]
(First embodiment)
Next, the configuration of the compressor 2 of the first embodiment provided in the compression heat pump system 100 shown in FIG. 1 will be described with reference to FIG.
The compressor 2 of the first embodiment converts the working medium X, which is carbon dioxide, supplied from the working medium flow path 7 to the compression chamber 26 by the rotation of the compression rotor 25 accommodated in the compression chamber 26 in the main body 23. It is configured as a vane rotary compressor that compresses as a fluid to be compressed and discharges it to the working medium flow path 8 side.
[0022]
One end of the drive shaft 21 of the compression rotator 25 is exposed outside the main body 23 as a connection portion 22 connected via a belt 12 to a connection portion 52 of a drive shaft 51 of an engine 50 as an external rotation drive source. The drive shaft 21 of the compressor 2 is rotationally driven by the driving force of an engine 50 installed outside.
[0023]
Further, in a cylindrical shaft space 29 between the drive shaft 21 of the compressor 2 and the main body 23, a first shaft seal portion S1 and a second shaft seal portion S2 are provided along the drive shaft 21 for the compression rotation. They are arranged side by side in the order described from the child 25 side to the connecting portion 22.
[0024]
Each of the first shaft seal portion S1 and the second shaft seal portion S2 includes a seal ring 31, 35 inserted in the shaft space 29 slidably along the axial direction of the drive shaft 2, and a drive shaft 21. The fixing rings 32 and 36 are fixedly mounted and driven to rotate together with the drive shaft 21 to slidably contact the seal end surfaces 31 a and 35 a of the seal rings 31 and 35, and the seal rings 31 and 35 are connected to the main ring 32 and 36. Are configured as known mechanical seals provided with springs 30 and 34 for urging the springs.
[0025]
The cylindrical shaft space 29 between the drive shaft 21 of the compressor 2 and the main body 23 is provided with the first shaft seal portion S1 and the second shaft seal portion S2 as described above, so that The first space 27 extends from the seal end surface 31a of the first shaft seal portion S1 to the seal end surface 31a of the single shaft seal portion S1, and the second space 28 extends from the seal end surface 31a of the first shaft seal portion S1 to the seal end surface 35a of the second shaft seal portion S2. Will be.
[0026]
The working medium X compressed in the compression chamber 26 flows out into the first space 27 via a bearing or the like, and the pressure in the first space 27 is, for example, about 9.0 to 10 MPa. It is considered that the working medium X becomes pressure, and there is a possibility that the working medium X flows out to the outside (atmosphere) through the second space 28 as it is.
[0027]
Therefore, unlike the working medium X, the compressor 2 includes a tank 40 for storing a sealed fluid Y such as air or nitrogen which has no problem even if it leaks to the atmosphere in a high pressure state. The sealing fluid Y is supplied to the second space 28 as the sealing fluid space via the sealing fluid flow path 38 formed of a tube material, and the pressure in the second space 28 is reduced to the discharge pressure of the working medium X. That is, the pressure of the sealing fluid Y supplied from the tank 40 to the second space 28 is adjusted so that the pressure is lower than the pressure in the first space 27 and is a pressure outside the main body 23, that is, higher than the atmospheric pressure. And a pressure regulating valve 39 that performs the operation.
[0028]
That is, the tank 40, the sealing fluid channel 38, and the pressure regulating valve 39 supply the sealing fluid Y to the second space 28 as the sealing fluid space, and set the pressure of the second space 28 to the set pressure. It functions as a sealing fluid supply unit A to be used.
[0029]
By providing the sealing fluid supply means A, the first shaft seal portion S1 is configured such that the working medium X in the first space 27, which is the discharge pressure, is lower than the discharge pressure and the external pressure such as the atmospheric pressure. It is sufficient that the mechanical seal is of such a degree as to suppress the outflow into the second space 28 having a higher set pressure. Further, the second shaft seal portion S2 may be a mechanical seal that prevents the sealing fluid Y in the second space 28 at the set pressure from flowing out of the main body 23 at an atmospheric pressure lower than the set pressure. Just fine. Therefore, under the pressure difference between the operating pressure of the compressor 2 and the atmospheric pressure outside the main body 23, the flow of the working medium X and the sealing fluid Y is suppressed. Even if the discharge pressure of the working medium X is extremely high, for example, about 9.0 to 10 MPa, the above-described differential pressure is small in each of the shaft seal portions S1 and S2, the operation is not performed. Outflow of the medium X and the sealing fluid Y can be sufficiently suppressed.
[0030]
Further, since the sealing fluid Y is air, nitrogen, or the like, there is no problem even if a small amount flows out of the second space 28 to the atmosphere via the second shaft seal portion S2. Therefore, the set pressure which is the pressure in the second space 28 is different from the operating pressure so that the outflow of the working medium X from the first space 27 to the second space 28 in the first shaft seal portion S1 can be satisfactorily prevented. It is preferable that the pressure is set higher so that the pressure difference becomes smaller.
[0031]
In the present embodiment, when the compressor 2 is stopped, the pressure regulating valve 39 is forcibly closed in order to reduce the pressure in the second space 28 from the set pressure to about the atmospheric pressure. Preferably, the supply of the sealing fluid Y to the space 28 is stopped.
[0032]
(Second embodiment)
Next, a configuration of the compressor 20 of the second embodiment provided in the compression heat pump system 100 shown in FIG. 1 will be described with reference to FIG.
In the compressor 20 of the second embodiment, the same components as those of the compressor 2 of the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted, but the same vane rotary as the compressor 2 of the first embodiment is omitted. The driving shaft 21 of the compressor 2 is driven to rotate by the driving force of the engine 50.
[0033]
Further, in a cylindrical shaft space 29 between the drive shaft 21 of the compressor 20 and the main body 23, a first shaft seal portion S1 and a second shaft seal portion S2 are provided along the drive shaft 21 to perform the compression rotation. The first shaft seal portion S1 and the second shaft seal portion S2 are arranged as mechanical seals in the stated order from the child 25 side to the connection portion 22.
[0034]
The cylindrical shaft space 29 between the drive shaft 21 of the compressor 20 and the main body 23 is provided with the first shaft seal portion S1 and the second shaft seal portion S2 as described above, thereby forming the first space 27 and the second shaft seal portion S2. It is divided into two spaces 28.
[0035]
The compressor 20 of the present embodiment is built in the main body 23, takes in the air as the sealing fluid Y from outside the main body 23 through the sealing fluid flow path 41, compresses the taken-in sealing fluid Y, and then seals the air. Compressing means B for supplying to the second space 28 as a sealing fluid space via the stop fluid flow path 44, and the pressure on the second space 28 side is set so that the pressure in the second space 28 becomes the above-mentioned set pressure. A pressure regulating valve for opening the valve when the pressure becomes higher and discharging the sealing fluid Y from the second space to the outside of the main body via the sealing fluid flow path; Then, the compression means B, the sealing fluid passages 41, 44, 45 and the pressure regulating valve 46 supply the sealing fluid Y to the second space 28 as the sealing fluid space and reduce the pressure of the second space 28. It functions as the sealing fluid supply means A for setting the above set pressure.
[0036]
The compression means B is driven by the rotation of a compression rotator 42 housed in a compression chamber 43 in the main body 23 and connected to the drive shaft 21. The second space is configured as a vane rotary compressor that compresses a certain sealing fluid Y and discharges the sealing fluid Y to the sealing fluid channel 44 side, and utilizes a part of the rotational driving force of the engine 50 transmitted to the drive shaft 21. It is configured to compress the sealing fluid Y supplied to 28.
[0037]
By providing the compression means B as described above, it is not necessary to provide the tank 40 for accumulating and storing the sealing fluid Y as in the first embodiment, and replenish the sealing fluid Y at the set pressure. Time can be saved.
Moreover, since the sealing fluid Y supplied to the second space 28 is compressed by using a part of the rotational driving force of the engine 50 by such a compression means B, when the engine 50 and the compressor 20 are stopped, The pressure in the two spaces 28 can be reduced from the set pressure.
In the present embodiment, the compression means B is built in the main body 23. However, the compression means B is separately provided outside the main body 23 and is connected to the drive shaft 51 of the engine 50 via a belt or the like and driven. May be configured.
[0038]
[Another embodiment]
In the first and second embodiments, in order to set the pressure in the second space 28 to the set pressure, the pressure control valve 39 is opened and closed by pressure fluctuations in the flow path and sets the pressure in the flow path to the set pressure. Although the control valve 46 is used, a control valve that can be opened and closed by a control signal from a control device or the like is provided instead of the pressure adjusting valves 39 and 46, and control is performed based on a detection result of a pressure sensor that detects the pressure in the second space 28. The pressure of the second space 28 may be set to the set pressure by feedback-controlling the valve.
[0039]
In the above embodiment, the working medium X is carbon dioxide. However, the working medium used in the present invention may be any working medium used in a normal heat pump system. Further, as the working medium X, ethane, Xenon, nitrous oxide and the like can also be used.
[0040]
In the above embodiment, the compressors 2 and 20 are so-called single-stage compressors that compress the working medium X in one compression chamber 26. However, the compressors 2 and 20 compress the working medium X in a plurality of compression chambers. It may be configured as a multi-stage compressor.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a compression heat pump. FIG. 2 is a diagram showing a configuration of a compressor of a first embodiment. FIG. 3 is a diagram showing a configuration of a compressor of a second embodiment.
2, 20: compressor 3: radiator 4: expansion valve 5: heat absorber 7, 8, 9, 10: working medium flow path 21: drive shaft 22: connecting part 23: body 25: compression rotor 26: compression chamber 27 : First space 28: Second space (sealed fluid space)
29: Shaft space 38: Sealing fluid channel 39: Pressure regulating valve 40: Tanks 41, 44, 45: Sealing fluid channel 42: Compression rotor 43: Compression chamber 46: Pressure regulating valve 50: Engine 100: Compression Heat pump system A: sealing fluid supply means B: compression means S1: first shaft seal portion S2: second shaft seal portion X: working medium Y: sealing fluid

Claims (4)

A fluid to be compressed is configured to be compressible by rotational driving of a compression rotor housed in the main body, and one end of a drive shaft of the compression rotor is exposed outside the main body as a connection portion connected to an external rotation drive source. The compressor being
A plurality of shaft seal portions are arranged in a shaft space between the drive shaft and the main body along the drive shaft, and
A sealing fluid is supplied to a sealing fluid space formed between the plurality of shaft seal portions of the shaft space, and a pressure of the sealing fluid space is lower than a discharge pressure of the fluid to be compressed and outside the main body. A compressor provided with a sealing fluid supply means for setting a set pressure higher than the pressure of the compressor. The sealing fluid supply unit includes a compression unit that compresses the sealing fluid supplied to the sealing fluid space by using a part of the rotation driving force of the external rotation driving source. The compressor according to claim 1. 3. The compressor according to claim 1, wherein the fluid to be compressed is carbon dioxide. A compression heat pump system comprising the compressor according to any one of claims 1 to 3, as a compressor for compressing a working medium in the compression heat pump as the fluid to be compressed.

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