CN112728795A

CN112728795A - Centrifugal compressor and refrigerating system with isolation liquid tank

Info

Publication number: CN112728795A
Application number: CN202110058986.8A
Authority: CN
Inventors: 商萍君; 施蔚兰; 朱倩; 单正娅; 芮长颖
Original assignee: Wuxi Institute of Technology
Current assignee: Wuxi Institute of Technology
Priority date: 2021-01-17
Filing date: 2021-01-17
Publication date: 2021-04-30

Abstract

The invention discloses a centrifugal compressor with an isolation liquid tank and a refrigeration system, which comprise a motor, wherein the motor is fixedly connected with a compressor through a gas bearing assembly, and the centrifugal compressor and the refrigeration system have the following beneficial effects that: whether a refrigerant exists in an evaporator or a condenser or an auxiliary evaporator or not does not need to be considered, and only the condenser, the evaporator and the auxiliary evaporator need to be directly or indirectly discharged into a separation liquid tank by a part of refrigerant liquid in a shell of the compressor before the compressor is started when liquid in the evaporator, the evaporator and the auxiliary evaporator stops, the full liquid of the refrigerant liquid is stored in the separation liquid tank, so that the refrigerant liquid can be fully filled in a suction pipeline of a first refrigerant pump no matter the compressor is started or the compressor runs, the continuous and reliable safe running of the liquid pump is ensured, the auxiliary evaporator is ensured to have enough liquid supply all the time, and the high-pressure gas supply flow of a stable gas bearing is ensured.

Description

Centrifugal compressor and refrigerating system with isolation liquid tank

Technical Field

The invention relates to a centrifugal compressor and a refrigeration system, in particular to a centrifugal compressor with an isolation liquid tank and a refrigeration system, and belongs to the technical field of centrifugal compressors.

Background

The existing technology is a semi-closed centrifugal compressor adopting a rolling bearing, a sliding bearing or a magnetic suspension bearing, the technical development trend requires oil-free lubrication, maintenance of a lubrication oil circuit system, oil circuit management, oil return management and maintenance of the oil circuit system are eliminated, the oil-free lubrication also represents higher operation efficiency of the compressor and the refrigeration system, lower vibration, noise and operation stability are achieved, and customer experience is better.

The centrifugal compressor adopting the air bearing can provide bearing air supply with required pressure by high-pressure exhaust of a refrigerating system when the refrigerating system operates; during start-up and shut-down, special designs are required to ensure stable bearing air supply to ensure that mechanical contact and wear do not occur; in particular, in case of sudden power failure, the air supply pressure difference of the air bearing is insufficient due to the sudden cut-off of the air supply power of the bearing, and the motor operating at high speed directly falls on the landing bearing or the support spring to cause the damage of the components such as the air bearing, so that a special design is required to ensure the safe landing of the air bearing compressor under the condition of sudden power failure.

Disclosure of Invention

The invention provides a centrifugal compressor with an isolation liquid tank and a refrigeration system, which effectively solve the problems in the prior art.

In order to solve the technical problems, the invention provides the following technical scheme:

the invention relates to a centrifugal compressor and a refrigeration system with an isolated liquid tank, which comprises a motor, wherein the motor is fixedly connected with the compressor through a gas bearing assembly, a bearing air supply pipeline branch, an air suction pipeline and a pipeline from a bearing to an air suction pipeline are fixedly connected on the motor, the pipeline from the bearing to the air suction pipeline is connected with the bearing air supply pipeline branch and the air suction pipeline, a fifth filter and a bearing air return pressure sensor are fixedly connected on the air suction pipeline, the bearing air supply pipeline branch is fixedly connected with a bearing air supply pipeline I through a bearing main air supply pipeline, a bearing air supply electronic expansion valve, a seventh filter, a bearing air supply pressure sensor and an air supply temperature sensor are fixedly connected on the bearing main air supply pipeline I, a bearing air supply one-way valve of an auxiliary evaporator is fixedly connected on the bearing air supply pipeline I, bearing air supply line one is through two fixedly connected with exhaust pipelines of compressor carminative bearing air supply line, the carminative bearing air feed check valve of fixedly connected with compressor on the carminative bearing air supply line two of compressor, exhaust pipeline and compressor fixed connection, the junction fixedly connected with exhaust pressure transducer of exhaust pipeline and compressor, fixedly connected with exhaust pipeline check valve and exhaust temperature sensor on the exhaust pipeline, a bearing air supply line fixedly connected with auxiliary evaporator, auxiliary evaporator and bearing air supply line one's junction fixedly connected with auxiliary evaporator pressure sensor, fixedly connected with auxiliary evaporator level sensor and refrigerant heater on the auxiliary evaporator, the auxiliary evaporator passes through condenser exhaust pipeline fixedly connected with liquid phase pipeline, fixedly connected with condenser export confession liquid check valve on the condenser fluid-discharge pipeline, The refrigerant pump I, the sixth filter and the suction stop valve, a liquid phase temperature sensor is fixedly connected to the liquid phase pipeline, a condenser is fixedly connected to the liquid phase pipeline, a condensing pressure sensor and a condenser liquid level sensor are fixedly connected to the condenser, a liquid feeding pipeline cooled by a motor is fixedly connected to the joint of the condenser liquid discharging pipeline and the liquid phase pipeline through a liquid feeding pipeline cooled by the motor, a fourth filter and an electronic expansion valve cooled by the motor are fixedly connected to the liquid feeding pipeline cooled by the motor, an evaporator is fixedly connected to the liquid feeding pipeline cooled by the motor through a main liquid feeding pipeline of the evaporator, a main liquid feeding electronic expansion valve is fixedly connected to the main liquid feeding pipeline of the evaporator, the main liquid feeding pipeline of the evaporator is fixedly connected to the auxiliary evaporator through a liquid discharging pipeline of the auxiliary evaporator, and an electromagnetic valve of the liquid discharging pipeline of the auxiliary evaporator is fixedly connected to the liquid discharging, the evaporator is fixedly connected with an evaporation pressure sensor, the evaporator is fixedly connected to the motor through a pipeline from the motor to the isolation liquid tank and an isolation liquid tank through a pipeline from the evaporator to the isolation liquid tank, the evaporator is fixedly connected with the isolation liquid tank through a pipeline from the evaporator to the isolation liquid tank and an exhaust pipeline of the isolation liquid tank, the evaporator is fixedly connected with a second filter, a refrigerant pump III and a check valve of the liquid supply value isolation liquid tank through the pipeline from the evaporator to the isolation liquid tank, the isolation liquid tank is fixedly connected with an exhaust solenoid valve of the isolation liquid tank, the connection part of the isolation liquid tank and the exhaust pipeline of the isolation liquid tank is fixedly connected with an isolation liquid tank liquid level sensor, the isolation liquid tank is fixedly connected with a main liquid supply pipeline of the evaporator through a liquid discharge pipeline of the isolation liquid tank, an evaporator liquid discharge pipeline and a liquid discharge pipeline from a condenser to the evaporator sequentially, and a liquid discharge pipeline of the condenser discharging liquid to the evaporator is fixedly connected with a condenser liquid discharge pipe electromagnetic valve.

As a preferable technical scheme of the invention, the one-way valve of the liquid supply value isolation liquid tank of the evaporator is fixedly connected with a pipeline from the evaporator to the isolation liquid tank through two pipelines, and the two pipelines are respectively and fixedly connected with pipelines from part of the evaporator on two sides of the refrigerant pump to the isolation liquid tank.

As a preferable technical scheme of the invention, the refrigerant pump II is fixedly connected on a liquid discharge pipeline of the isolation liquid tank through two pipelines, and the refrigerant pump II and the liquid supply one-way valve at the outlet of the evaporator are arranged in parallel.

As a preferable technical scheme of the invention, the condenser is connected with a joint of the second bearing air supply pipeline and the exhaust pipeline of the compressor exhaust.

The invention has the following beneficial effects: whether a refrigerant exists in an evaporator or a condenser or an auxiliary evaporator or not does not need to be considered, and only the condenser, the evaporator and the auxiliary evaporator need to be directly or indirectly discharged into a separation liquid tank by a part of refrigerant liquid in a shell of the compressor before the compressor is started when liquid in the evaporator, the evaporator and the auxiliary evaporator stops, the full liquid of the refrigerant liquid is stored in the separation liquid tank, so that the refrigerant liquid can be fully filled in a suction pipeline of a first refrigerant pump no matter the compressor is started or the compressor runs, the continuous and reliable safe running of the liquid pump is ensured, the auxiliary evaporator is ensured to have enough liquid supply all the time, and the high-pressure gas supply flow of a stable gas bearing is ensured.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a first flow chart of the present invention;

FIG. 2 is a second flow chart of the present invention;

FIG. 3 is a third flow chart of the present invention;

FIG. 4 is a fourth flow chart of the present invention;

fig. 5 is a flow chart of the present invention.

In the figure: 1. a motor; 2. a gas bearing assembly; 3. a compressor; 4. a condenser; 5. an evaporator; 6. an auxiliary evaporator; 7. isolating the liquid tank; 8. a first refrigerant pump; 9. a second refrigerant pump; 10. a third refrigerant pump; 11. an exhaust line check valve; 12. the bearing air supply one-way valve for compressor exhaust; 13. a bearing air supply one-way valve of the auxiliary evaporator; 14. a liquid supply one-way valve is arranged at the outlet of the evaporator; 15. a liquid supply one-way valve is arranged at the outlet of the condenser; 16. a main liquid supply electronic expansion valve; 17. the electric motor cools the liquid supply electronic expansion valve; 18. bearing air supply electronic expansion valve; 19. isolating a liquid storage tank exhaust pipe electromagnetic valve; 20. a condenser drain solenoid valve; 21. auxiliary evaporator drain solenoid valves; 22. a first filter; 23. a second filter; 24. a third filter; 25. a fourth filter; 26. a fifth filter; 27. a sixth filter; 28. a seventh filter; 29. a refrigerant heater; 30. the evaporator is provided with a one-way valve for isolating the liquid supply value from the liquid tank; 31. a suction stop valve; 101. an exhaust line; 102. an air intake pipeline; 103. a liquid phase pipeline; 104. a main liquid supply pipeline of the evaporator; 105. a condenser drain line; 106. an evaporator drain line; 107. the condenser discharges liquid to a liquid discharge pipeline of the evaporator; 108. a line from the evaporator to the isolated liquid tank; 109. a drain line isolating the liquid tank; 110. isolating an exhaust pipeline of the liquid storage tank; 111. an auxiliary evaporator drain line; 112. a bearing air supply pipeline I; 113. a second bearing air supply pipeline for exhausting air of the compressor; 114. a bearing main gas supply line; 115. a bearing air supply pipeline branch; 116. a pipeline for returning air to the air suction pipeline from the bearing; 117. a pipeline for cooling the motor and returning liquid to the evaporator; 118. a motor-cooled liquid supply line; p200, exhaust pressure sensor; p201, a condensation pressure sensor; p202, an evaporation pressure sensor; p203, a bearing air supply pressure sensor; p204, a bearing return air pressure sensor; p205, auxiliary evaporator pressure sensor; t200, an exhaust gas temperature sensor; t201, a liquid phase temperature sensor; t202, an air supply temperature sensor; l200, an auxiliary evaporator liquid level sensor; l201, a condenser liquid level sensor; l202, isolating the liquid level sensor of the liquid tank.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1: as shown in fig. 1-5, the centrifugal compressor and refrigeration system with isolated liquid tank of the present invention comprises a motor 1, wherein the motor 1 is fixedly connected with a compressor 3 through a gas bearing assembly 2, the motor 1 is fixedly connected with a bearing air supply pipeline branch 115, an air suction pipeline 102 and a pipeline 116 of a bearing air return-to-air suction pipeline, the pipeline 116 of the bearing air return-to-air suction pipeline is connected with the bearing air supply pipeline branch 115 and the air suction pipeline 102, the air suction pipeline 102 is fixedly connected with a fifth filter 26 and a bearing air return pressure sensor P204, the bearing air supply pipeline branch 115 is fixedly connected with a first bearing air supply pipeline 112 through a main bearing air supply pipeline 114, the main bearing air supply pipeline 114 is fixedly connected with an electronic bearing air supply expansion valve 18, a seventh filter 28, a bearing air supply pressure sensor P203 and an air supply temperature sensor T202, bearing air feed check valve 13 that fixedly connected with auxiliary evaporator on bearing air supply line 112, bearing air supply line 112 is through two 113 fixedly connected with exhaust pipe 101 of the carminative bearing air supply line of compressor, fixedly connected with compressor carminative bearing air feed check valve 12 on two 113 of the carminative bearing air supply line of compressor, exhaust pipe 101 and compressor 3 fixed connection, exhaust pipe 101 and compressor 3's junction fixedly connected with exhaust pressure sensor P200, fixedly connected with exhaust pipe check valve 11 and exhaust temperature sensor T200 on exhaust pipe 101, bearing air supply line 112 fixedly connected with auxiliary evaporator 6, auxiliary evaporator 6 and bearing air supply line 112's junction fixedly connected with auxiliary evaporator pressure sensor P205, fixedly connected with auxiliary evaporator level sensor L200 and refrigerant heater 29 on auxiliary evaporator 6, the auxiliary evaporator 6 is fixedly connected with a liquid phase pipeline 103 through a condenser liquid discharge pipeline 105, a condenser outlet liquid supply one-way valve 15, a refrigerant pump I8, a sixth filter 27 and an air suction stop valve 31 are fixedly connected on the condenser liquid discharge pipeline 105, a liquid phase temperature sensor T201 is fixedly connected on the liquid phase pipeline 103, a condenser 4 is fixedly connected on the liquid phase pipeline 103, the condenser 4 is connected with the joint of a compressor exhaust bearing air supply pipeline II 113 and an exhaust pipeline 101, a condensing pressure sensor P201 and a condenser liquid level sensor L201 are fixedly connected on the condenser 4, the joint of the condenser liquid discharge pipeline 105 and the liquid phase pipeline 103 is fixedly connected with a motor 1 through a motor-cooled liquid supply pipeline 118, a fourth filter 25 and a motor-cooled liquid supply electronic expansion valve 17 are fixedly connected on the motor-cooled liquid supply pipeline 118, the liquid supply pipeline 118 of the motor cooling is fixedly connected with an evaporator 5 through an evaporator main liquid supply pipeline 104, the evaporator main liquid supply pipeline 104 is fixedly connected with a main liquid supply electronic expansion valve 16, the evaporator main liquid supply pipeline 104 is fixedly connected with an auxiliary evaporator 6 through an auxiliary evaporator liquid discharge pipeline 111, the auxiliary evaporator liquid discharge pipeline 111 is fixedly connected with an auxiliary evaporator liquid discharge pipe electromagnetic valve 21, the evaporator 5 is fixedly connected with an evaporation pressure sensor P202, the evaporator 5 is fixedly connected with a motor 1 through a pipeline 117 of the motor cooling liquid return to the evaporator, the evaporator 5 is connected with an air suction pipeline 102, the evaporator 5 is fixedly connected with an isolation liquid tank 7 through a pipeline 108 from the evaporator to the isolation liquid tank and an isolation liquid storage tank exhaust pipeline 110, and a second filter 23, a third filter and a fourth filter are fixedly connected on the pipeline 108 from the evaporator to the isolation liquid tank, The refrigerant pump III 10 and the evaporator liquid supply value isolating liquid tank check valve 30 are fixedly connected to an isolating liquid tank exhaust pipe solenoid valve 19 on an isolating liquid tank exhaust pipeline 110, an isolating liquid tank liquid level sensor L202 is fixedly connected to the joint of the isolating liquid tank 7 and the isolating liquid tank exhaust pipeline 110, the isolating liquid tank 7 is fixedly connected with an evaporator main liquid supply pipeline 104 through a liquid discharge pipeline 109 of the isolating liquid tank, an evaporator liquid discharge pipeline 106 and a liquid discharge pipeline 107 of the condenser liquid discharge to the evaporator in sequence, a third filter 24, a first filter 22, an evaporator outlet liquid supply check valve 14 and a refrigerant pump II 9 are fixedly connected to the liquid discharge pipeline 109 of the isolating liquid tank, and a condenser liquid discharge pipeline solenoid valve 20 is fixedly connected to the liquid discharge pipeline 107 of the evaporator in sequence.

The check valve 30 of the liquid supply value isolation liquid tank of the evaporator is fixedly connected to a pipeline 108 from the evaporator to the isolation liquid tank through two pipelines, and the two pipelines are respectively and fixedly connected with pipelines 108 from part of the evaporators at two sides of the refrigerant pump III 10 to the isolation liquid tank.

The second refrigerant pump 9 is fixedly connected to a liquid discharge pipeline 109 of the isolation liquid tank through two pipelines, and the second refrigerant pump 9 and the evaporator outlet liquid supply one-way valve 14 are arranged in parallel.

Specifically, the pump liquid supply circuit and the bearing gas supply circuit are provided with an isolation liquid tank 7, (a) a liquid phase pipeline 103 from the condenser, a liquid discharge pipeline 107 from the condenser to the evaporator, a liquid discharge electromagnetic valve 20 through the condenser, and a part of the refrigerant in the condenser 4 is introduced into the shell of the evaporator 5, (b) a pipeline 108 from the evaporator to the isolation liquid tank, a part of the refrigerant in the evaporator 5 is introduced into the isolation liquid tank 7 through the assembly of the refrigerant pump III 10 and the check valve 30, (c) during the process of introducing the liquid from the evaporator, the electromagnetic valve 19 needs to be opened, so that the pipeline 110 is conducted, the redundant gas in the isolation liquid tank 7 is discharged into the shell of the evaporator 5, the isolation liquid tank 7 can be fully filled, and the pressure of the isolation liquid tank 7 and the pressure of the evaporator 5 can be balanced during the operation of the compressor 3, ensuring that the pressure of the isolation liquid tank 7 is the same as the pressure of the evaporator 5, (d) through the suction action of the refrigerant pump I8, the refrigerant liquid in the isolation liquid tank 7 flows through the liquid discharge pipeline 109 of the isolation liquid tank, the condenser liquid discharge pipeline 105 and the condenser outlet liquid supply one-way valve 15 and finally enters the shell of the auxiliary evaporator 6, the refrigerant pump I8 can increase the pressure of the refrigerant liquid to be about 0.35 MPa-0.55 MPa higher than the pressure of the isolation liquid tank 7 and then enters the auxiliary evaporator 6, (e) the refrigerant heater 29 flashes the high-pressure refrigerant liquid in the auxiliary evaporator 6 into high-pressure refrigerant gas, and then the high-pressure refrigerant gas flows through the bearing air supply one-way valve 13 of the auxiliary evaporator and finally is supplied to the gas bearing assembly 2 through the bearing air supply pipeline I112, the bearing main air supply pipeline 114 and the bearing air supply pipeline branch 115, forming a high pressure gas film to generate sufficient air-float radial force and air-float thrust, (f) flowing a portion of the refrigerant liquid from the outlet of the liquid phase line 103 through the liquid discharge solenoid valve 31 and the condenser liquid discharge line 105 of the condenser 4 into the first refrigerant pump 8, flowing a portion of the refrigerant liquid from the bottom outlet of the evaporator 5 through the assembly of the evaporator liquid discharge line 106 and the second refrigerant pump 9 and the evaporator outlet liquid feed check valve 14 into the first refrigerant pump 8, flowing from the barrier liquid tank 7 through the liquid discharge line 109 and the condenser liquid discharge line 105 of the barrier liquid tank, the three portions of liquid being mixed together to provide a parallel liquid feed to the first refrigerant pump 8 prior to startup of the compressor 3, once the compressor 3 is started, the condenser liquid discharge solenoid valve 31 is closed, the condenser liquid discharge line 105 is open, avoiding filling liquid from the high pressure condenser 4 into the barrier liquid tank 7 in the low pressure region, (g) the refrigerant in the auxiliary evaporator 6 flows through the isolation liquid storage tank exhaust pipe electromagnetic valve 19 and the auxiliary evaporator liquid discharge pipeline 111 and is discharged into the shell of the evaporator 5, before the compressor 3 is started, the auxiliary evaporator liquid discharge pipe electromagnetic valve 21 is opened, the auxiliary evaporator liquid discharge pipeline 111 is conducted, all the refrigerant in the auxiliary evaporator 6 is discharged into the evaporator 5, the refrigerant liquid in the auxiliary evaporator 6 is at low pressure in the standby process, even if the refrigerant liquid is heated and flashed into gas, the refrigerant liquid is low-pressure gas and is not enough to generate the pressure difference required by bearing gas supply, so that the liquid needs to be discharged, the refrigerant liquid is transferred into high-pressure liquid which is 0.35 MPa-0.55 MPa higher than the low pressure through the refrigerant pump I8, once the compressor 2 is started, the auxiliary evaporator liquid discharge pipe electromagnetic valve 21 of the auxiliary evaporator 6 is closed, and the auxiliary evaporator liquid discharge pipeline 111 is closed.

When the compressor exhaust bearing air supply loop works, (a) before the compressor 3 is started, a condenser liquid discharge electromagnetic valve 20 is opened, a liquid discharge pipeline 107 for discharging liquid from the condenser to the evaporator is opened, an auxiliary evaporator liquid discharge pipeline electromagnetic valve 21 of the auxiliary evaporator 6 is opened, an auxiliary evaporator liquid discharge pipeline 111 is opened, an isolation liquid storage tank exhaust pipeline 19 is opened, an isolation liquid storage tank exhaust pipeline 110 is opened, a refrigerant pump III 10 and a one-way valve 30 of an evaporator liquid supply value isolation liquid tank are started as necessary under the action of gravity, refrigerant liquid is filled into a shell of the isolation liquid tank 7 until a liquid level sensor L202 of the isolation liquid tank indicates that the liquid level is full, then a refrigerant pump I8 is started, high-pressure refrigerant pressure which is 0.35 MPa-0.55 MPa higher than standby pressure is pressurized and enters the auxiliary evaporator 6, a refrigerant heater 29 is started, the high-pressure refrigerant liquid is flashed into high-pressure refrigerant gas, finally providing high-pressure bearing gas supply, (b) after the compressor 2 is started, closing a condenser liquid discharge pipe electromagnetic valve 20 to prevent the condenser 4 and the evaporator 5 from being directly conducted, closing an auxiliary evaporator liquid discharge pipe electromagnetic valve 21 to prevent high-pressure liquid in the auxiliary evaporator 6 and the evaporator 5 from being directly conducted, confirming whether to operate a refrigerant pump III 10 according to the liquid level displayed by an isolating liquid tank liquid level sensor L202, keeping the isolating liquid tank 7 at a full liquid level position all the time, monitoring the pressure difference between the condensing pressure of a condensing pressure sensor P201 and the evaporating pressure of an evaporating pressure sensor P202 in real time during the operation of the compressor 3, if the pressure difference is more than 0.35 MPa-0.55 MPa + offset, closing the related refrigerant pump, and supplying gas to the gas bearing assembly 2 by adopting the exhaust gas of the compressor through an exhaust pipeline 101 and a bearing gas supply pipeline II 113 for exhausting the compressor, closing the air supply pipeline 112 of the auxiliary evaporator 6, (c) when the compressor 3 is stopped, starting a related refrigerant pump, closing the bearing air supply pipeline one 112, realizing delayed bearing air supply, meanwhile, the condenser 4 is a huge container of high-pressure gas, the gas in the container can pass through the bearing air supply pipeline two 113 for compressor exhaust and the bearing air supply one-way valve 12 for compressor exhaust, the gas can provide high-pressure air supply for the gas bearing assembly 2 for about 15-20s continuously, and when the power is cut off suddenly, the delayed high-pressure air supply of the gas bearing assembly 2 can also be realized through the exhaust of the condenser 4, which is effective for the design of the permanent magnet motor, because the gas in the container can quickly carry out high-low pressure balance through the communicated pipelines, and because the flow ports of the main liquid supply electronic expansion valve 16 and the motor cooling liquid supply electronic expansion valve 17 are small, the exhaust pipeline one-way valve 11 and the bearing air supply one-way valve 13 of the auxiliary evaporator prevent the air from passing through, the condenser liquid discharge pipe electromagnetic valve 20 and the air suction stop valve 31 are closed, therefore most of the air is balanced to the low pressure side through the bearing air supply pipeline II 113 exhausted by the compressor, but the air can only last for 15 to 20s, the high pressure and the low pressure are balanced, the rotor of the permanent magnet motor is a permanent magnet, the power is cut off suddenly, the stator magnetic field disappears, the rotor magnetic field is equivalent to the reverse excitation braking action, the complete stop within 5 to 10s can be ensured generally, the air supply time of 15 to 20s can be longer than the time from the rotation to the complete stop within 5 to 10s, but the system design is also required to ensure, but the situation that only the permanent magnet motor is adopted, the power supply of the sudden power cut-off of the air bearing assembly 2 can be ensured, reliability is guaranteed and asynchronous induction machines are unusable.

Embodiment 2 on the basis of fig. 1, in fig. 2, the evaporator liquid discharge pipe 106, the second refrigerant pump 9 on the pipe and the one-way valve 14 for liquid supply at the outlet of the evaporator are not needed, the condenser liquid discharge pipe 105, namely the pipe between the liquid phase pipe 103 and the condenser liquid discharge pipe 105, is not needed, the suction stop valve 31 is not needed, only the refrigerant liquid flows out of the isolating liquid tank 7 and flows through the liquid discharge pipe 109 of the isolating liquid tank and the condenser liquid discharge pipe 105, the liquid supply before the start of the compressor 3 is provided to the first refrigerant pump 8, therefore, all the refrigerant liquid is finally gathered into the isolating liquid tank 7, and the liquid pump 8 only needs to pump the low-pressure refrigerant liquid from the isolating liquid tank, and the isolating liquid tank 7 is always kept full of liquid.

Example 3: in fig. 3, on the basis of fig. 1, the refrigerant in the auxiliary evaporator 6 flows through the isolation liquid storage tank exhaust pipe electromagnetic valve 19 and the auxiliary evaporator liquid discharge pipeline 111 and is discharged into the isolation liquid tank 7, before the compressor 3 is started, the auxiliary evaporator liquid discharge pipeline electromagnetic valve 21 is opened, the auxiliary evaporator liquid discharge pipeline 111 is conducted, the refrigerant in the auxiliary evaporator 6 is completely discharged into the evaporator 5, the refrigerant liquid in the part is at low pressure in the standby process, even if the refrigerant liquid is heated and flashed into gas, the refrigerant liquid is low-pressure gas and is not enough to generate the pressure difference required by bearing gas supply, so the liquid needs to be discharged, the refrigerant liquid is transferred into high-pressure liquid which is 0.35-0.55 MPa higher than the low pressure through the refrigerant pump I8, once the compressor 3 is started, the auxiliary evaporator liquid discharge pipeline 21 of the auxiliary evaporator 6 is closed, the auxiliary evaporator liquid discharge pipeline 111 is closed, and the same as considered above, it is only necessary to ensure that the barrier fluid tank 7 is full of fluid at any time.

Example 4: in addition to fig. 3, in the system of fig. 4, which employs a flooded evaporator, the liquid supply line of the flooded evaporator is at the bottom of the shell of the evaporator 5, and the liquid phase line 103 is also at the bottom of the shell of the condenser 5, so that the condenser drain solenoid valve 20 of the drain line 107 of the condenser is not needed, and a portion of the refrigerant liquid in the condenser can be drained into the evaporator 5 by opening the main liquid supply electronic expansion valve 16 of the evaporator 5 to a certain degree of opening just before the compressor 3 is started.

Example 5: fig. 5 is a flow diagram and embodiment of a complete refrigeration system as in fig. 1, except that fig. 5 employs a flooded evaporator design and fig. 1 employs a falling film evaporator design.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The utility model provides a centrifugal compressor and refrigerating system of liquid tank are kept apart in area, includes motor (1), its characterized in that, motor (1) is through gas bearing subassembly (2) fixedly connected with compressor (3), fixedly connected with bearing air supply pipeline branch road (115), suction pipeline (102) and bearing return-air to suction pipeline's pipeline (116) are gone up in motor (1), bearing return-air is connected to suction pipeline's pipeline (116) and bearing air supply pipeline branch road (115) and suction pipeline (102), fixedly connected with fifth filter (26) and bearing return-air pressure sensor (P204) on suction pipeline (102), bearing air supply pipeline branch road (115) are through bearing main air supply pipeline (114) fixedly connected with bearing air supply pipeline one (112), fixedly connected with bearing air feed electronic expansion valve (18) on bearing main air supply pipeline (114), Seventh filter (28), bearing air feed pressure sensor (P203) and air feed temperature sensor (T202), bearing air feed check valve (13) of fixedly connected with auxiliary evaporator on bearing air supply line (112), bearing air supply line (112) is through compressor carminative bearing air supply line two (113) fixedly connected with exhaust pipe (101), on compressor carminative bearing air supply line two (113) fixedly connected with compressor carminative bearing air feed check valve (12), exhaust pipe (101) and compressor (3) fixed connection, the junction fixedly connected with exhaust pressure sensor (P200) of exhaust pipe (101) and compressor (3), fixedly connected with exhaust pipe check valve (11) and exhaust temperature sensor (T200) on exhaust pipe (101), bearing air supply line (112) fixedly connected with auxiliary evaporator (6), the auxiliary evaporator (6) and the bearing air supply pipeline I (112) are fixedly connected with an auxiliary evaporator pressure sensor (P205), the auxiliary evaporator (6) is fixedly connected with an auxiliary evaporator liquid level sensor (L200) and a refrigerant heater (29), the auxiliary evaporator (6) is fixedly connected with a liquid phase pipeline (103) through a condenser liquid discharge pipeline (105), a condenser outlet liquid supply one-way valve (15), a refrigerant pump I (8), a sixth filter (27) and an air suction stop valve (31) are fixedly connected onto the condenser liquid discharge pipeline (105), a liquid phase temperature sensor (T201) is fixedly connected onto the liquid phase pipeline (103), a condenser (4) is fixedly connected onto the liquid phase pipeline (103), and a condensation pressure sensor (P201) and a condenser liquid level sensor (L201) are fixedly connected onto the condenser (4), the condenser liquid discharge pipeline (105) and the liquid phase pipeline (103) are fixedly connected with the motor (1) through a motor-cooled liquid supply pipeline (118), the motor-cooled liquid supply pipeline (118) is fixedly connected with a fourth filter (25) and a motor-cooled liquid supply electronic expansion valve (17), the motor-cooled liquid supply pipeline (118) is fixedly connected with the evaporator (5) through an evaporator main liquid supply pipeline (104), the evaporator main liquid supply pipeline (104) is fixedly connected with a main liquid supply electronic expansion valve (16), the evaporator main liquid supply pipeline (104) is fixedly connected with the auxiliary evaporator (6) through an auxiliary evaporator liquid discharge pipeline (111), the auxiliary evaporator liquid discharge pipeline (111) is fixedly connected with an auxiliary evaporator liquid discharge pipe electromagnetic valve (21), and the evaporator (5) is fixedly connected with an evaporation pressure sensor (P202), evaporimeter (5) return liquid to pipeline (117) fixed connection of evaporimeter through motor cooling on motor (1), evaporimeter (5) are connected with suction line (102), evaporimeter (5) are through pipeline (108) of evaporimeter to isolation liquid jar and isolation liquid storage pot exhaust pipe (110) fixedly connected with isolation liquid jar (7), fixedly connected with second filter (23), three (10) of refrigerant pump and one-way valve (30) of evaporimeter liquid value isolation liquid jar are gone up to pipeline (108) of isolation liquid jar to the evaporimeter, fixedly connected with keeps apart blast pipe solenoid valve (19) on isolation liquid storage pot exhaust pipe (110), keep apart liquid jar (7) and keep apart liquid storage pot exhaust pipe's (110) junction fixedly connected with and keep apart liquid jar liquid level sensor (L202), it loops through liquid discharge pipe (109) of isolation liquid jar to keep apart liquid jar (7), The evaporator liquid discharge pipeline (106) and the condenser liquid discharge pipeline (107) discharging liquid to the evaporator are fixedly connected with the evaporator main liquid supply pipeline (104), the liquid discharge pipeline (109) of the isolation liquid tank is fixedly connected with a third filter (24), a first filter (22), an evaporator outlet liquid supply one-way valve (14) and a refrigerant pump II (9), and the condenser liquid discharge pipeline electromagnetic valve (20) is fixedly connected onto the liquid discharge pipeline (107) discharging liquid to the evaporator.

2. The centrifugal compressor and refrigeration system with an insulating liquid tank as recited in claim 1 wherein said evaporator feed value insulating liquid tank check valve (30) is fixedly connected to evaporator to insulating liquid tank piping (108) by two pipes, and said two pipes are fixedly connected to a portion of evaporator to insulating liquid tank piping (108) on both sides of refrigerant pump three (10), respectively.

3. The centrifugal compressor and refrigeration system with the isolated liquid tank as recited in claim 1, wherein the second refrigerant pump (9) is fixedly connected to the drain line (109) of the isolated liquid tank through two pipes, and the second refrigerant pump (9) and the evaporator outlet liquid feed check valve (14) are arranged in parallel.

4. The centrifugal compressor and refrigeration system with isolated liquid tank as claimed in claim 1, characterized in that the condenser (4) is connected to the junction of the compressor discharge bearing air supply line two (113) and the discharge line (101).