JP2000179486A - Half-closing screw compressor for refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a half-closing screw compressor for a refrigerator capable of effectively cooling a motor. SOLUTION: In a screw compressor for compressing a cooling medium gas and a half-closing screw compressor for a refrigerator provided with a motor, a rotator 1-5 of the motor 1-3 is directly connected to a shaft end at a suction end side of a screw rotor 1-2 of the screw compressor and a stator 1-7 is disposed on an outer periphery thereof. The rotator 1-5 and the stator 1-7 of the motor 1-3 are sealingly accommodated in a main casing 1-1 by a partition wall 1-1a and a shaft seal means 1-8 to a degree that it is not communicated with an atmosphere and a suction side atmosphere of the screw rotor 1-2 or it is communicated with them by a thin hole. A cooling medium liquid introducing means for introducing a cooling medium liquid for a refrigeration cycle for cooling the rotator 1-5 and the stator 1-7 of the motor 1-3 is provided in the main casing 1-1. A passage 10 for communicating an inside space of the main casing 1-1 sealingly accommodating the rotator 1-5 and the stator 1-7 of the motor 1-3 with an intermediate compression portion of the screw rotor 1-2 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semi-hermetic screw compressor for a refrigerator having a screw compressor for compressing refrigerant gas.

[0002]

2. Description of the Related Art FIG. 1 is a view showing an example of the configuration of a conventional semi-hermetic screw compressor for a refrigerator of this type. FIG. 1 (a) is a longitudinal sectional view, and FIG. FIG. Semi-hermetic screw compressor for refrigerator is casing 10
1 is a configuration in which a motor 102 and a screw rotor 103 are housed. The motor rotor 10 of the motor 102 is attached to the end of the rotation shaft 105 on the suction end side B of the screw rotor 103.
The rotary shaft 105 is rotatably supported by bearings 106. Further, a motor stator 107 is arranged on the outer periphery of the motor rotor 104. Casing 1
A suction cover 110 is provided on the shaft end side of the screw rotor 103 of No. 01 on the suction end side, and a suction filter 109 is provided in an opening 110 a formed in the center thereof.

[0003] On the outer periphery of the motor stator 107, a flow path 10 is provided.
8 are arranged. Refrigerant gas sucked through the suction filter 109 by the screw rotor 103 which is a positive displacement compression mechanism is sucked into the screw rotor 103 through the flow path 108 and the suction port 111. In this way, by passing all of the suction refrigerant gas through the flow path 108 provided on the outer periphery of the motor stator 107, heat generated due to the loss of the motor 102 is removed.

[0004]

The above-mentioned suction refrigerant gas is
Since it is a dry gas given a certain degree of superheat by the expansion valve, only the sensible heat can be cooled, and there is a problem that the cooling efficiency is lower than the flow rate of the refrigerant gas. As a measure against this,
Although it is conceivable to increase the gas flow rate in order to improve heat transfer, there is a problem that increasing the gas flow rate increases the pressure loss. Furthermore, there is a problem that the specific volume is increased by depriving the heat of the motor 102, and the refrigerant circulation amount of the refrigeration cycle is greatly reduced.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to provide a semi-hermetic screw compressor for a refrigerator capable of effectively cooling a motor.

[0006]

According to one aspect of the present invention, there is provided a refrigerator comprising a screw compressor for compressing refrigerant gas and a motor for driving a screw rotor of the screw compressor. In the semi-hermetic screw compressor for, while directly connecting the rotor of the motor to the shaft end on the suction end side of the screw rotor of the screw compressor,
The stator of the motor is arranged on the outer periphery, and the rotor and the stator of the motor are not communicated with the atmosphere and the suction side atmosphere of the screw rotor by the partition wall and the shaft sealing means in the casing, or are communicated by pores. Housed hermetically,
The casing is provided with a refrigerant liquid introducing means for introducing a refrigerant liquid of a refrigeration cycle for cooling the rotor and the stator of the motor, and the space inside the casing that hermetically accommodates the rotor and the stator of the motor is screwed. A passage communicating with the intermediate compression portion of the rotor is provided, and pressure equalizing holes are provided at the top and bottom of the outer periphery of the stator of the motor.

As described above, the rotor and the stator of the motor are hermetically housed in the casing so that the partition and the shaft seal means do not communicate with the atmosphere and the atmosphere on the suction side of the screw rotor, or communicate with the suction hole of the screw rotor. Therefore, the temperature does not rise without the motor coming into contact with the suctioned refrigerant gas. Further, since it is not necessary to increase the pressure loss such as the flow path of the refrigerant gas around the stator of the motor as in the conventional example, the specific volume of the refrigerant gas at the time of suction of the screw rotor is small, and the refrigerant of the refrigeration cycle It does not reduce the amount of circulation.

Further, since the casing is provided with a refrigerant liquid introducing means for introducing a refrigerant liquid of a refrigeration cycle for cooling the rotor and the stator of the motor, these refrigerants are cooled by the latent heat of the refrigerant liquid. Direct with liquid flow rate,
It becomes possible to cool efficiently. In particular, when a refrigerant having a small specific volume such as NH _{3 and a} large latent heat is used, the flow rate of the refrigerant liquid for cooling the motor is extremely small, but equalizing holes are provided at the top and bottom of the outer periphery of the motor stator. Thereby, the distribution of the refrigerant becomes uniform, and the heated gas does not stay in the upper part of the space containing the motor,
The cooling efficiency of the motor is improved.

The invention described in claim 2 is the first invention.
In the semi-hermetic screw compressor for a refrigerator described in (1), an opening of a passage for communicating a space inside the casing that hermetically accommodates a rotor and a stator of the motor with an intermediate compression portion of the screw rotor is provided at a lower portion of the casing. It is characterized by the following.

As described above, the opening of the passage for communicating the space inside the casing which hermetically accommodates the rotor and the stator of the motor with the intermediate compression portion of the screw rotor is provided at the lower portion of the casing. The non-evaporated refrigerant liquid and refrigeration oil remaining in the lower portion of the load side in the storage space can also be returned to the economizer port opened to the intermediate pressure of the screw rotor.

[0011] The invention according to claim 3 is based on claim 1.
Or, in the semi-hermetic screw compressor for a refrigerator according to 2, the pores that communicate the inside of the casing containing the rotor and the stator of the motor with the atmosphere on the suction side of the screw rotor are located at the lower part of the casing, and It is characterized by returning the refrigerant liquid and the refrigerating machine oil to the suction side atmosphere.

As described above, the pores communicating the inside of the casing accommodating the rotor and the stator of the motor and the suction side atmosphere of the screw rotor are located at the lower portion of the casing, and the refrigerant liquid that has not completely evaporated and the refrigerating machine oil Is returned to the suction side atmosphere, the motor housing space of the casing has a function as a gas-liquid separator of the economizer, and a separate gas-liquid separator can be omitted.

The invention described in claim 4 is the first invention.
In the semi-hermetic screw compressor for a refrigerator according to any one of claims 1 to 3, the refrigerant liquid introducing means includes an air between the stator and the rotor provided to at least one of the stator and the rotor of the motor. It is characterized in that it has a passage communicating with the gap, and is a means for introducing the refrigerant liquid of the refrigeration cycle into the communicating passage and the coil end surface of the stator.

The invention described in claim 5 is the first invention.
The semi-hermetic screw compressor for a refrigerator according to any one of the above-mentioned items 4, wherein the refrigerant is supercooled by a supercooling heat exchanger of an economizer cycle.

[0015] The invention described in claim 6 is the first invention.
The semi-hermetic screw compressor for a refrigerator according to any one of the first to fifth aspects, wherein the refrigerant liquid absorbs heat to a wet saturated vapor phase by a supercooling heat exchanger of an economizer cycle.

The invention described in claim 7 is the first invention.
7. The semi-hermetic screw compressor for a refrigerator according to any one of the above items 6 to 6, wherein the refrigerant is ammonia (NH ₃ ).

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing a configuration example of a refrigeration cycle including a semi-hermetic screw compressor for a refrigerator according to the present invention, and FIG. 2 (a) is an overall configuration and a vertical cross-sectional view of a semi-hermetic screw compressor for a refrigerator. 2 (b) shows an AA cross section of the semi-hermetic screw compressor for the refrigerator of FIG. The basic cycle of the refrigerator is compression, condensation (exhaust heat), expansion, and evaporation (endotherm). Each process is performed by the compressor 1, the condenser 2, the main expansion valve 3, and the evaporator 4. As the compressor 1, a semi-hermetic screw compressor for a refrigerator according to the present invention is used. The condenser 2 is provided with a cooling water pipe 11 for supplying cooling water, and the evaporator 4 is provided with a cooling water pipe 12 for supplying cold water.

In the present embodiment, a supercooling heat exchanger 6 and an economizer expansion valve 7 are arranged in the refrigerant liquid line 5 to forcibly supercool the refrigerant liquid, thereby forcing the cooling effect of the refrigeration cycle. Are increasing. As the compressor 1, a semi-hermetic screw compressor capable of opening an intermediate pressure section during compression is used.

The main casing 1-1 of the compressor 1 hermetically houses a screw rotor 1-2 and a motor 1-3 as a compression mechanism. A rotor 1-5 of a motor 1-3 is provided at a shaft end of a rotation shaft 1-4 of the screw rotor 1-2, and the rotation shaft 1-4 is rotatably supported by a bearing 1-20. A stator 1-7 is provided on the outer periphery of the rotor 1-5 with a gap of a motor air gap 1-6 therebetween.
-1 are provided integrally. A suction cover 1 is provided on the open end side of the screw rotor 1-2 of the main casing 1-1.
10 are provided. In FIG. 2, B indicates the open end side, and C indicates the load side.

The rotor 1-5 and the stator 1-7 constituting the motor 1-3 are separated from the suction refrigerant gas sucked into the screw rotor 1-2 by the partition wall 1-1a and the shaft sealing means 1-8 such as a labyrinth. It does not touch. The heat source of the motor 1-3 is mainly composed of the rotor 1-5 and the stator 1-
7 and a secondary loss generated in the open end side coil end 1-7a and the load side coil end 1-7b of the stator 1-7. It is.

In order to effectively remove the heat generated by the primary loss and the secondary loss, a motor cooling line 8 is provided downstream of the supercooling heat exchanger 6 of the refrigerant liquid line 5, and the motor cooling line 8 is provided. The main casing 1-1 and a stator 1-7 of a motor 1-3 communicate with a motor air gap 1-6 through a stator communication passage 1-9 provided in a stator 1-7. Communication hole 1-10a provided in 10
Through the open end side coil end 1-7a of the stator 1-7
The main casing 1-1 communicates with a housing space D of a motor 1-3 via a spray nozzle 1-11 provided opposite to the main body 1-1.

The motor cooling line 8 passes through a communication hole 1-10b of a suction cover 1-10 and a communication hole 1-4a provided on a rotating shaft 1-4 of a screw rotor 1-2.
A rotor communication path 1- provided in a rotor 1-5 of the motor 1-3;
Through 5a, it communicates with the motor air gap 1-6. Further, the motor cooling line 8 is provided to face the open end side coil end 1-7a of the stator 1-7 through the communication hole 1-10b of the suction cover 1-10, and the rotating shaft of the screw rotor 1-2 is provided. Splasher 1 provided at the end of 1-4
12 is open to the inner circumference.

A subcooling branch line 9 is provided downstream of the subcooling heat exchanger 6 of the refrigerant liquid line 5, and passes through the economizer expansion valve 7 and the subcooling heat exchanger 6 to pass through the main casing 1.
-1 communicates with the housing space D of the motor 1-3 of the main casing 1-1 via an economizer filter 1-13 provided opposite the load side coil end 1-7b of the stator 1-7. .

The refrigerant passing through the motor cooling line 8 is a subcooling refrigerant liquid, the refrigerant passing downstream of the subcooling heat exchanger 6 in the subcooling branch line 9 is a wet saturated vapor refrigerant, and the spray nozzle 1-11. From the main casing 1-1
The refrigerant released into the storage space D of 3 is a wet saturated vapor refrigerant in the form of spray, and the refrigerant released from the splasher 1-12 to the open end side coil end 1-7a of the stator 1-7 is supercooled in the form of droplets. It is a refrigerant liquid. The flow rate of each refrigerant is adjusted by flow rate control means (not shown) such as an orifice.

As a means for recovering the refrigerant which has been opened to the space of the main casing 1-1 and cooled the motor 1-3, an economizer port of the screw rotor 1-2 passes through an opening 1-14 provided in the main casing 1-1. A refrigerant recovery line 10 that opens to 1-15 is provided. An upper pressure equalizing hole 1-16 is provided on the outer periphery of the stator 1-7 of the motor 1-3, and the pressure on the open end side B and the load side C of the housing space D of the motor 1-3 of the main casing 1-1 is increased. At the same time, the high-temperature refrigerant gas staying in the upper portion of the open end B of the housing space D is discharged to the load side C.

A lower pressure equalizing hole 1-17 is provided on the outer periphery of the stator 1-7 of the motor 1-3 to reduce the pressure on the open end side B and the load side C of the accommodation space D of the motor 1-3. At the same time, the refrigerating machine oil staying below the open end B of the accommodation space D of the motor 1-3 is discharged to the load side C. By providing the opening 1-14 in the lower part of the main casing 1-1, the refrigerant liquid and the refrigeration oil that have not completely evaporated and that remain in the lower part of the load side C of the housing space D of the motor 1-3 can also be cooled by the screw rotor 1-2. It is configured to be introduced into the economizer port 1-15 that opens to the intermediate pressure.

Further, unlike the conventional example, the path of the suction refrigerant gas of the present embodiment passes through the suction filter 1-18,
The motor 1-1 of the main casing 1-1 is separated by a partition wall 1-1a provided on the main casing 1-1 and a shaft sealing means 1-8.
3 is a suction port 1- which is a space isolated from the storage space D.
19 is introduced.

With the above configuration of the semi-hermetic screw compressor for a refrigerator, which is the compressor of the refrigeration cycle, the motor 1-3 is connected to the suction refrigerant gas by the shaft sealing means 1-8 such as the partition wall 1-1a and the labyrinth. Does not contact and does not heat.
In addition, as in the conventional example shown in FIG. 1, it is not necessary to increase the pressure loss of the flow path 108 and the like through which the refrigerant gas sucked into the casing 101 passes.
The refrigerant gas specific volume at the time of suction of -2 may be small, and the refrigerant circulation amount of the refrigeration cycle is not reduced.

The motor air gaps 1 of the rotors 1-5 and the stators 1-7, which are main heat sources of the motor 1-3, respectively.
The primary loss generated in the vicinity of the cylindrical surface facing -6 and the secondary loss generated in the open end coil end 1-7a and the load side coil end 1-7b of the stator 1-7 are defined by the motor air gap. It can be cooled by the latent heat of the supercooled refrigerant liquid passing through 1-6. Further, the open-end coil end 1-7a can be cooled by the spray-type wet saturated vapor refrigerant and the spray-like supercooled refrigerant, and the load-side coil end 1-7b can be cooled by the wet saturated vapor refrigerant. Since the cooling is performed by the latent heat of the refrigerant liquid, the refrigerant liquid can be directly and efficiently cooled with a small refrigerant liquid flow rate.

The opening 1-14 is connected to the main casing 1-1.
Is provided at the lower part of the housing, so that the accommodation space D
The non-evaporated refrigerant liquid and refrigerant oil remaining on the load side C can be returned to the economizer port 1-15 opened to the intermediate pressure of the screw rotor 1-2.

FIG. 3 is a view showing an example of the configuration of a refrigeration cycle equipped with a semi-hermetic screw compressor for a refrigerator according to the present invention. FIG. FIG. 3B is a sectional view taken along line AA of the semi-hermetic screw compressor for a refrigerator shown in FIG. is there. In FIG. 3, portions denoted by the same reference numerals as those in FIG. 2 indicate the same portions. The difference between the semi-hermetic screw compressor for a refrigerator of FIG. 3 and the semi-hermetic screw compressor for a refrigerator of FIG. 2 is that the main casing of the semi-hermetic screw compressor (compressor) 1 for the refrigerator in FIG. An opening (pore) 1 having a small diameter communicating with the suction port 1-19 below the load side C (the lower part of the partition wall 1-1a) of the accommodation space D of the motor 1-3 of FIG.
21 is provided.

As described above, the suction port 1-1 is provided below the load side C of the housing space D of the motor 1-3 of the main casing 1-1.
By providing an opening 1-21 communicating with the housing 9, the housing space D of the motor 1-3 of the main casing 1-1 has a function as a gas-liquid separator of the economizer, and a separately installed gas-liquid separator is omitted. it can.

[0033]

As described above, according to the present invention, the following excellent effects can be obtained.

According to the invention described in each claim, the rotor and the stator of the motor are not communicated with the atmosphere and the atmosphere on the suction side of the screw rotor by the partition wall and the shaft sealing means, or are communicated by the pores in the casing. Since the configuration is such that the motor is housed in a hermetically closed state, the motor does not come into contact with the suctioned refrigerant gas and the temperature does not rise. In addition, since it is possible to omit the pressure loss increase such as the flow path of the refrigerant gas around the stator of the motor as in the conventional example, the volume of the refrigerant gas at the time of suction of the screw rotor may be small, and the refrigeration cycle may be reduced. There is no decrease in refrigerant circulation.

Further, since the casing is provided with refrigerant liquid introduction means for introducing the refrigerant liquid of the refrigeration cycle for cooling the rotor and the stator of the motor, these cooling is performed by the latent heat of the refrigerant liquid. Direct with liquid flow rate,
It becomes possible to cool efficiently. In particular, when a refrigerant having a small specific volume such as NH _{3 and a} large latent heat is used, the flow rate of the refrigerant liquid for cooling the motor becomes extremely small.However, it is necessary to provide pressure equalizing holes at the top and bottom of the outer periphery of the motor stator. Thereby, the distribution of the refrigerant becomes uniform, and the heated gas does not stay in the upper part of the space containing the motor,
The cooling efficiency of the motor is improved.

According to the second aspect of the present invention, in addition to the above-described effects, the opening of the passage for communicating the space inside the casing which hermetically accommodates the rotor and the stator of the motor with the intermediate compression portion of the screw rotor is provided. Since it is provided in the lower part of the casing, the refrigerant liquid and the refrigeration oil that have not completely evaporated and remain in the lower part of the casing in the load side in the motor accommodating space can be returned to the economizer port that opens to the intermediate pressure of the screw rotor.

According to the third aspect of the present invention, in addition to the above-described effects, the pores for communicating the inside of the casing accommodating the rotor and the stator of the motor with the atmosphere on the suction side of the screw rotor are located at the lower portion of the casing. Since the refrigerant is returned to the suction side atmosphere, the motor housing space of the casing has a function as a gas-liquid separator of the economizer, and a separate gas-liquid separator can be omitted.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration example of a conventional semi-hermetic screw compressor for a refrigerator, FIG. 1 (a) is a longitudinal sectional view, and FIG.
It is -A sectional drawing.

FIG. 2 is a view showing a configuration example of a refrigeration cycle including a semi-hermetic screw compressor for a refrigerator according to the present invention.
2A is a longitudinal sectional view of the entire configuration and a semi-hermetic screw compressor for a refrigerator, and FIG. 2B is an AA sectional view of the semi-hermetic screw compressor for the refrigerator in FIG.

FIG. 3 is a diagram showing a configuration example of a refrigeration cycle including a semi-hermetic screw compressor for a refrigerator according to the present invention.
FIG. 3A is a longitudinal sectional view of the entire configuration and a semi-hermetic screw compressor for a refrigerator, and FIG. 3B is an A-A sectional view of the semi-hermetic screw compressor for the refrigerator of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 1-1 Main casing 1-2 Screw rotor 1-3 Motor 1-4 Rotary shaft 1-5 Rotor 1-6 Motor air gap 1-7 Stator 1-8 Shaft sealing means 1-9 Stator stator Passageway 1-10 Suction cover 1-11 Spray nozzle 1-12 Slasher 1-13 Economizer filter 1-14 Opening 1-15 Economizer port 1-16 Upper equalizing hole 1-17 Lower equalizing hole 1-18 Suction filter 1 Reference Signs List 19 suction port 1-20 bearing 1-21 opening 2 condenser 3 main expansion valve 4 evaporator 5 refrigerant liquid line 6 supercooling heat exchanger 7 economizer expansion valve 8 motor cooling line 9 subcooling branch line 10 refrigerant recovery Line 11 Cooling water piping 12 Cold water piping

Claims (7)

[Claims] 1. A semi-hermetic screw compressor for a refrigerator comprising a screw compressor for compressing refrigerant gas and a motor for driving a screw rotor of the screw compressor, wherein a suction end side of the screw rotor of the screw compressor is provided. The rotor of the motor is directly connected to the shaft end of the motor, and the stator of the motor is arranged on the outer periphery of the motor. A refrigerant liquid that is hermetically accommodated so that it does not communicate with the suction side atmosphere of the rotor or communicates with the pores, and a refrigerant liquid for introducing a refrigerant liquid of a refrigeration cycle for cooling the rotor and the stator of the motor in the casing. An introduction means, and a space inside the casing that hermetically accommodates the rotor and the stator of the motor is provided with an intermediate pressure of the screw rotor. Parts a passage communicating provided, semi-sealed screw compressor for refrigerating machine, characterized in that a pressure equalization hole in the top and bottom of the stator outer periphery of the motor. 2. The semi-hermetic screw compressor for a refrigerator according to claim 1, wherein a space inside a casing that hermetically accommodates a rotor and a stator of the motor is communicated with an intermediate compression section of the screw rotor. A semi-hermetic screw compressor for a refrigerator, wherein an opening of a passage is provided at a lower portion of the casing. 3. The semi-hermetic screw compressor for a refrigerator according to claim 1 or 2, wherein a fine hole that communicates an inside of a casing containing a rotor and a stator of the motor with a suction side atmosphere of the screw rotor. A semi-hermetic screw compressor for a refrigerator, located at a lower part of a casing, for returning a refrigerant liquid or a refrigerator oil to a suction side atmosphere. 4. The semi-hermetic screw compressor for a refrigerator according to any one of claims 1 to 3, wherein the refrigerant liquid introducing means is provided on at least one of a stator and a rotor of the motor. A refrigerating machine characterized by comprising a passage communicating with an air gap between a stator and a rotor, and a means for introducing a refrigerant liquid of a refrigerating cycle into the communicating passage and to a coil end surface of the stator. Semi-hermetic screw compressor. 5. The semi-hermetic screw compressor for a refrigerator according to claim 1, wherein the refrigerant is subcooled by a subcooling heat exchanger of an economizer cycle. Semi-hermetic screw compressor for refrigerator. 6. The semi-hermetic screw compressor for a refrigerator according to any one of claims 1 to 5, wherein the refrigerant liquid absorbs heat to a wet saturated vapor phase by a supercooling heat exchanger of an economizer cycle. A semi-hermetic screw compressor for a refrigerator. 7. The semi-hermetic screw compressor for a refrigerator according to any one of claims 1 to 6, wherein the refrigerant is ammonia (NH ₃ ). Machine.