Anti-surge system of centrifugal compressor and air conditioner
By designing the anti-surge system of the centrifugal compressor and using the cooperation of the hot gas bypass pipe and the air supply pipe, the gas pressure balance in the compressor is achieved, the surge problem during low load operation is solved, and the stability of the unit is improved. and efficiency.
Patent Information
- Application Number
- CN202420242728.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-31
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2034-01-31
AI Technical Summary
Centrifugal compressors are prone to surge when operating at low loads, resulting in large current fluctuations, which poses a threat to the safety of the compressor and system.
An anti-surge system for centrifugal compressors is designed. The gas is led to the flash generator through the hot gas bypass pipe for cooling and pressure reduction, and the gas pressure in the compressor is balanced through the air supply pipe. The controller is used to adjust the bypass valve. and the opening of the electronic expansion valve to achieve pressure balance in the exhaust pipe.
It effectively prevents surge caused by excessive pressure difference between the condenser and compressor, improves the stability and safety of the unit during low-load operation, and improves unit efficiency.
Smart Images
Figure CN222376814U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of air-conditioning equipment, in particular to a centrifugal compressor anti-surge system and an air conditioner. Background Art
[0002] Due to the structural characteristics of centrifugal compressors, when the required current load is small, such as in spring, autumn, summer mornings and evenings, winter mornings and evenings, etc., the power of the centrifugal compressor (that is, the variable frequency unit) will be reduced. The exhaust pressure of the compressor will decrease as the compressor power decreases, but if the pressure in the condenser is high, gas backflow will occur, which is called surge. When surge occurs, it will cause large current fluctuations, which will have a great impact on the compressor, the entire system, and the power supply system, and there are great safety hazards.
[0003] The commonly used solution in the market now is to connect a hot gas bypass pipe between the exhaust pipe and the suction pipe of the unit. However, since the compressor exhaust will be accompanied by a small amount of lubricating oil, it will enter the suction pipe through the hot gas bypass and directly hit the centrifuge impeller, resulting in insufficient long-term operating reliability.
[0004] Therefore, the prior art needs to be further developed. Utility Model Content
[0005] The utility model aims to overcome the above technical deficiencies and provide a centrifugal compressor anti-surge system and air conditioner to solve the technical problem in the related art that the unit is prone to surge during low-load operation, causing damage to the unit.
[0006] In order to achieve the above technical objectives, the utility model adopts the following technical solutions: a centrifugal compressor anti-surge system is provided, comprising: an exhaust pipe, one end of which is connected to the air outlet of the compressor, and the other end of which is connected to the air inlet of the condenser; a hot gas bypass pipe, one end of which is connected to the exhaust pipe, and the other end of which is connected to the flasher, so that the flasher can cool down and reduce the pressure of the gas from the compressor; an intake pipe, one end of which is connected to the air outlet of the evaporator, and the other end of which is connected to the air inlet of the compressor.
[0007] Furthermore, the centrifugal compressor anti-surge system also includes an air supply pipe, one end of which is connected to the flasher, and the other end of which is connected to the compressor, and the air supply pipe is used to balance the gas pressure in the compressor.
[0008] Furthermore, a bypass valve is provided on the hot gas bypass pipe, and the hot gas bypass pipe is opened or closed by the bypass valve.
[0009] Furthermore, the centrifugal compressor anti-surge system also includes a controller, which is connected to the bypass valve signal, and the opening of the bypass valve is adjusted by the controller.
[0010] Furthermore, an electronic expansion valve is provided on the air supply pipe, and the air supply pipe is opened or closed by the electronic expansion valve.
[0011] Furthermore, the controller is connected to the electronic expansion valve signal, and the opening of the electronic expansion valve is adjusted by the controller.
[0012] Further, the flash discharge air outlet of the flasher is arranged at the top of the flasher, and the flash discharge liquid outlet of the flasher is arranged at the bottom of the flasher.
[0013] Furthermore, the flasher is provided with at least one flash air outlet and at least one flash liquid outlet, and at least one flash air outlet is connected to the air supply pipe.
[0014] Further, the air inlet of the compressor is located at the top of the compressor, and the air outlet of the compressor is located at the bottom of the compressor.
[0015] An air conditioner adopts the centrifugal compressor anti-surge system as described above.
[0016] Beneficial effects:
[0017] 1. The centrifugal compressor anti-surge system of the utility model uses a hot gas bypass pipe to guide part of the gas to the flasher, and then enters the compressor from the suction pipe after being cooled and depressurized by the flasher, so as to achieve pressure balance in the exhaust pipe and effectively prevent surge caused by excessive pressure difference between the condenser and the compressor.
[0018] 2. The centrifugal compressor anti-surge system of the utility model adopts the coordinated use of the hot gas bypass pipe and the air supply pipe, which not only realizes the operation of small cooling capacity, but also plays the role of air supply and enthalpy increase, thereby improving the efficiency of the unit.
[0019] 3. When the air conditioner of the utility model is adopted, there will be no surge phenomenon when running at a small load, which effectively protects the unit. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a schematic diagram of the system structure of the centrifugal compressor anti-surge adopted in the embodiment of the utility model;
[0021] Figure 2 It is a flow chart of the gas flow of the centrifugal compressor anti-surge system adopted in the embodiment of the utility model.
[0022] The above drawings include the following reference numerals:
[0023] 1. Exhaust pipe; 2. Compressor; 3. Condenser; 4. Hot gas bypass pipe; 41. Bypass valve; 5. Flasher; 6. Air supply pipe; 61. Electronic expansion valve; 7. Intake pipe; 8. Evaporator; 9. Main liquid pipe. DETAILED DESCRIPTION
[0024] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of this application.
[0025] According to an embodiment of the utility model, a centrifugal compressor anti-surge system is provided. Figure 1 to Figure 2 , including: an exhaust pipe 1, one end of which is connected to the air outlet of the compressor 2, and the other end of which is connected to the air inlet of the condenser 3; a hot gas bypass pipe 4, one end of which is connected to the exhaust pipe 1, and the other end of which is connected to the flasher 5, so that the flasher 5 can cool down and reduce the pressure of the gas from the compressor 2; an intake pipe 7, one end of which is connected to the air outlet of the evaporator 8, and the other end of which is connected to the air inlet of the compressor 2. Normally, the gas discharged from the compressor 2 enters the condenser 3 through the exhaust pipe 1, and the liquid refrigerant of the condenser 3 enters the flasher 5 after throttling through the main liquid pipe 9, and the liquid refrigerant of the flasher 5 enters the evaporator 8 through the main liquid pipe 9 after the second throttling, and the liquid refrigerant is converted into gaseous state through the evaporator 8, and finally the gaseous refrigerant is supplied to the secondary impeller of the compressor 2 through the intake pipe 7 for compression (such as Figure 2 As shown). When the unit is running at low load, the power of the variable frequency unit decreases, and the exhaust pressure of the compressor 2 will also decrease, but the pressure in the condenser 3 is relatively high, and surge is likely to occur. By adding a hot gas bypass pipe 4 to the exhaust pipe 1, the hot gas bypass pipe 4 is connected to the flasher 5, and the gas from the compressor 2 is diverted by the flasher 5, so that the gas entering the condenser 3 is reduced, thereby reducing the pressure difference between the compressor 2 and the condenser 3, and achieving pressure balance in the exhaust pipe 1, so as to ensure that the compressor 2 will not surge in the low load and low frequency range, thereby protecting the unit from normal operation at low load. The centrifugal compressor anti-surge system and air conditioner of this embodiment solve the technical problem in the related art that the unit is prone to surge when running at low load, causing damage to the unit.
[0026] In addition, since the exhaust of the compressor 2 is accompanied by a small amount of lubricating oil, if it enters the suction pipe 7 through the hot gas bypass pipe 4, it will directly hit the impeller of the compressor 2, which will cause risks in long-term operation. The anti-surge system of the centrifugal compressor of this embodiment realizes oil-liquid-gas separation through the sedimentation principle of the flasher 5, avoiding the quality risk of oil droplets directly hitting the impeller, and protecting the centrifugal compressor.
[0027] See also Figure 1 to Figure 2In the centrifugal compressor anti-surge system of the present embodiment, the centrifugal compressor anti-surge system further includes an air supply pipe 6, one end of which is connected to the flasher 5, and the other end of which is connected to the compressor 2, and the air supply pipe 6 is used to balance the gas pressure in the compressor 2. The air supply pipe 6 is added between the flasher 5 and the compressor 2, and the gas is cooled and depressurized by the flasher 5, and then directly enters between the first and second impellers of the compressor 2 from the air supply pipe 6, which can also play the role of air supply and enthalpy increase, thereby improving the unit efficiency.
[0028] See also Figure 1 In the centrifugal compressor anti-surge system of this embodiment, a bypass valve 41 is provided on the hot gas bypass pipe 4, and the hot gas bypass pipe 4 is opened or closed by the bypass valve 41. Due to the structural characteristics of the centrifugal compressor, the system is preset with a surge line in the system, which is equivalent to a surge warning value. When the surge line is close to the warning value, the bypass valve 41 is opened to pass part of the gas to the flasher 5 to cool and reduce the pressure of the gas.
[0029] Specifically, the bypass valve 41 is an electronic expansion valve.
[0030] In the centrifugal compressor anti-surge system of the present embodiment, the centrifugal compressor anti-surge system further includes a controller, which is connected to the bypass valve 41 by signal, and the opening of the bypass valve 41 is adjusted by the controller. When the unit is under the required load condition and the frequency is reduced to close to the surge line, the control system of the controller will release a signal to open the electronic expansion valve and adjust it to a suitable opening to protect the compressor 2.
[0031] See also Figure 1 In the centrifugal compressor anti-surge system of the present embodiment, an electronic expansion valve 61 is provided on the air supply pipe 6, and the air supply pipe 6 is opened or closed by the electronic expansion valve 61.
[0032] In the centrifugal compressor anti-surge system of this embodiment, the controller is connected to the electronic expansion valve 61 by signal, and the opening of the electronic expansion valve 61 is adjusted by the controller. Through the control logic preset by the controller control system, when the frequency is reduced, the electronic expansion valve 61 is opened, and the high-temperature and high-pressure refrigerant enters the condenser 3 through the exhaust pipe 1, and then enters the flash evaporator 5 after throttling, cooling and reducing pressure, so as to prevent the refrigerant of the flash evaporator 5 from flowing back to the condenser 3 due to excessive pressure. At the same time, part of the throttled refrigerant is converted into liquid refrigerant in the flash evaporator 5 and enters the evaporator 8, and part of the gaseous refrigerant directly enters between the first and second impellers of the compressor 2 from the air supply pipe 6 (two-stage compression), which can realize air supply and enthalpy increase to reduce the energy consumption of the unit.
[0033] See also Figure 1In the centrifugal compressor anti-surge system of the present embodiment, the flash outlet of the flasher 5 is arranged at the top of the flasher 5 to prevent the liquid in the flasher 5 from being carried by the gas when it flows out, thereby ensuring that the refrigerant entering the compressor 2 is gaseous.
[0034] In the centrifugal compressor anti-surge system of this embodiment, the liquid discharge port of the flasher 5 is arranged at the bottom of the flasher 5 to prevent the liquid from carrying gas when being discharged, thereby reducing gas loss.
[0035] In the anti-surge system of the centrifugal compressor of the present embodiment, the flasher 5 is provided with at least one flash outlet and at least one flash outlet, and at least one flash outlet is connected to the air supply pipe 6. The function of the flasher 5 is to convert the liquid refrigerant into gas after passing through the throttling device, and the separated gaseous refrigerant is led into the compressor 2 by the air supply pipe 6, and mixed with the refrigerant at the outlet of the previous impeller, so as to reduce the superheat of the refrigerant at the outlet of the impeller, and save compression work when the next stage of compression is performed. The provision of multiple flash outlets can quickly replenish more gas in the flasher 5 into the compressor 2, which not only prevents the refrigerant of the flasher 5 from flowing back to the condenser 3 due to excessive pressure, but also increases the compression work of the compressor 2.
[0036] In the centrifugal compressor anti-surge system of the present embodiment, the air inlet of compressor 2 is located at the top of compressor 2, and the air outlet of compressor 2 is located at the bottom of compressor 2, which not only effectively prevents the "liquid hammer" phenomenon, but also allows impurities to be easily discharged if they enter compressor 2, thereby avoiding damage to the cylinder and piston.
[0037] In the air conditioner of this embodiment, the centrifugal compressor anti-surge system as described above is adopted. This system uses the surge line pre-set in the system. When the unit is under the required load conditions and the frequency is reduced to close to the surge line, the controller will release a signal to open the bypass valve 41 and adjust the opening to protect the compressor 2. If it is close to the surge line and the pressure on the condenser side is high, a part of the pressure will be released into the air supply pipe 6 and the hot air bypass pipe 4, and finally the surge point frequency in the original state (without the air supply pipe 6) will be met. The surge will not affect the compressor 2, but will only surge inside the exhaust pipe 1. However, under the action of the hot air bypass pipe 4, the pressure will soon be balanced. The air conditioner of this embodiment realizes the pressure balance in the exhaust pipe 1 to ensure the use of the compressor 2 in the low load and low frequency range, so that the centrifugal compressor can adapt to more load conditions and meet the use needs of users in different locations, different time periods, and different environments.
[0038] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0039] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.
[0040] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.
[0041] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.
[0042] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.
Claims
1. A centrifugal compressor anti-surge system, characterized in that: include: An exhaust pipe (1), one end of the exhaust pipe (1) being connected to an air outlet of the compressor (2), and the other end of the exhaust pipe (1) being connected to an air inlet of the condenser (3); a hot gas bypass pipe (4), one end of the hot gas bypass pipe (4) being connected to the exhaust pipe (1), and the other end of the hot gas bypass pipe (4) being connected to a flasher (5), so that the flasher (5) can reduce the temperature and pressure of the gas from the compressor (2); An air intake pipe (7), one end of the air intake pipe (7) is connected to the air outlet of the evaporator (8), and the other end of the air intake pipe (7) is connected to the air inlet of the compressor (2).
2. The centrifugal compressor anti-surge system according to claim 1, characterized in that: The centrifugal compressor anti-surge system also includes an air supply pipe (6), one end of the air supply pipe (6) is connected to the flasher (5), and the other end of the air supply pipe (6) is connected to the compressor (2), and the air supply pipe (6) is used to balance the gas pressure in the compressor (2).
3. The centrifugal compressor anti-surge system according to claim 2, characterized in that: The hot gas bypass pipe (4) is provided with a bypass valve (41), and the hot gas bypass pipe (4) is opened or closed by the bypass valve (41).
4. The centrifugal compressor anti-surge system according to claim 3, characterized in that: The centrifugal compressor anti-surge system also includes a controller, which is connected to the bypass valve (41) by signal, and the opening of the bypass valve (41) is adjusted by the controller.
5. The centrifugal compressor anti-surge system according to claim 4, characterized in that: The air supply pipe (6) is provided with an electronic expansion valve (61), and the air supply pipe (6) is opened or closed by the electronic expansion valve (61).
6. The centrifugal compressor anti-surge system according to claim 5, characterized in that: The controller is connected to the electronic expansion valve (61) by signal, and the opening degree of the electronic expansion valve (61) is adjusted by the controller.
7. The centrifugal compressor anti-surge system according to claim 2, characterized in that: The flash discharge air outlet of the flasher (5) is arranged at the top of the flasher (5), and / or the flash discharge liquid outlet of the flasher (5) is arranged at the bottom of the flasher (5).
8. The centrifugal compressor anti-surge system according to claim 7, characterized in that: The flasher (5) is provided with at least one flash gas outlet and at least one flash liquid outlet, and at least one of the flash gas outlets is connected to the air supply pipe (6).
9. The centrifugal compressor anti-surge system according to claim 1, characterized in that: The air inlet of the compressor (2) is located at the top of the compressor (2), and the air outlet of the compressor (2) is located at the bottom of the compressor (2).
10. An air conditioner, characterized in that: A centrifugal compressor anti-surge system using any one of claims 1-9.