High speed motor cooling device based on looped unpowered heat pipe

Abstract

The utility model relates to a kind of high-speed motor cooling device based on annular unpowered heat pipe, it includes compressor and the cooling mechanism being set in the exterior of compressor, the cooling mechanism includes with the exhaust pipe and reflux pipe being connected with the compressor shell, the connecting position of the exhaust pipe and reflux pipe with the compressor shell is respectively located the both sides of stator in axial direction, the compressor shell inner wall is provided with the venturi injection pipe being connected with the reflux pipe, the outer end of the exhaust pipe and reflux pipe is connected with condensing component.The high-speed motor cooling device, it is directly set on the compressor shell, the magnetic suspension motor and magnetic bearing cooling in the compressor shell interior, independent of heat pump refrigerant circulation, can realize motor internal evaporation temperature lower than the motor temperature control of high-temperature heat pump system evaporation temperature.On the basis of guaranteeing motor safety, motor coil and rotor temperature are greatly reduced, prolong motor life, improve motor efficiency.

Description

Technical Field

[0001] This utility model relates to the field of motor cooling technology, specifically to a high-speed motor cooling device based on annular non-powered heat pipes. Background Technology

[0002] One of the technical challenges of high-temperature and ultra-high-temperature heat pump systems for industrial applications is the pyrolysis and deterioration of compressor lubricating oil at high temperatures. Therefore, oil-free magnetic levitation high-speed direct-drive centrifugal compressors are almost the only option for high-temperature heat pumps with heating temperatures above 140°C. When high-temperature heat pumps recover industrial waste heat, the temperature of this waste heat often exceeds 80°C or even higher. This means that the evaporation temperature of the high-temperature heat pump will be higher than 75°C or even higher, and the condensation temperature will be higher than 140°C or even higher. In such high-evaporation and high-condensation systems, the minimum working fluid temperature reaches 75°C. Since the insulation temperature of ordinary Class A motors is below 105°C, the simple cooling method commonly used in traditional refrigeration units, which involves spraying low-temperature refrigerant into the motor, is insufficient to ensure adequate motor cooling.

[0003] Therefore, this application proposes to use annular heat pipes combined with Venturi ejectors to realize an independent cooling device for high-speed motors that is independent of the heat pump refrigerant cycle. This allows for temperature control of the motor and magnetic bearings, ensuring that the internal evaporation temperature of the motor is lower than that of the high-temperature heat pump system. While ensuring motor safety, this significantly reduces the temperature of the motor coils and rotor, extends motor life, and improves motor efficiency. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to provide a high-speed motor cooling device based on a ring-shaped non-powered heat pipe, which has a good cooling effect, is independent of the heat pump refrigerant circulation, and can achieve motor temperature control with the internal evaporation temperature of the motor lower than the evaporation temperature of the high-temperature heat pump system.

[0005] To solve the above problems, the technical solution adopted by this utility model is as follows:

[0006] A high-speed motor cooling device based on a ring-shaped non-powered heat pipe includes a compressor and a cooling mechanism disposed outside the compressor. The cooling mechanism includes an exhaust pipe and a return pipe connected to the compressor housing. The connection positions of the exhaust pipe and the return pipe to the compressor housing are respectively located on both sides of the stator. A Venturi ejector tube connected to the return pipe is provided on the inner wall of the compressor housing. The outer ends of the exhaust pipe and the return pipe are connected to a condensation assembly.

[0007] In one embodiment of this utility model, the condensation assembly includes a plurality of condenser tubes arranged side by side at an angle. The two ends of the condenser tubes are respectively connected to an exhaust pipe and a return pipe, and the end of the condenser tube connected to the exhaust pipe is higher than the end of the condenser tube connected to the return pipe.

[0008] In one embodiment of this utility model, heat dissipation fins are provided on the outside of the condenser tube; a fan is provided below the condenser tube to blow air toward the condenser tube.

[0009] As one embodiment of this utility model, the Venturi ejector tube is generally arc-shaped to match the contour of the inner wall of the compressor housing. The Venturi ejector tube is provided with an air inlet and an injection port at both ends, wherein the air inlet faces the direction of rotor rotation, and the injection port faces the direction of rotor rotation. The middle part of the Venturi ejector tube is connected to the return pipe.

[0010] In one embodiment of this utility model, the compressor includes a compressor housing and a rotor disposed within the compressor housing. The end of the rotor is connected to a compression impeller. A stator is disposed in the middle of the inner wall of the compressor housing. A front bearing and a rear bearing are respectively disposed at the front and rear ends of the stator. The connection positions of the exhaust pipe and the return pipe to the compressor housing are located outside the front bearing and the rear bearing, respectively.

[0011] In one embodiment of this utility model, both the front bearing and the rear bearing are magnetic levitation bearings. The gap between the stator and the magnetic levitation bearing and the rotor forms an annular gas flow channel, and the two ends of the gas flow channel are connected to the exhaust pipe and the return pipe, respectively.

[0012] In one embodiment of this utility model, the exhaust pipe and the return pipe are arranged vertically, and the height of the exhaust pipe is higher than that of the return pipe. A gas distributor and a liquid storage chamber are respectively provided at the upper ends of the exhaust pipe and the return pipe. The condenser includes a straight pipe section in the middle and bent pipe sections at both ends. The two ends of the condenser are connected to the gas distributor and the liquid storage chamber through the bent pipe sections.

[0013] In one embodiment of this utility model, the heat dissipation fins include a plurality of fins evenly arranged, the fins being perpendicular to the axial direction of the straight pipe section and arranged side by side along the length of the straight pipe section of the condenser tube, and the heat dissipation fins being provided with through holes corresponding to each straight pipe section.

[0014] The beneficial effects of adopting the above technical solution are as follows:

[0015] This invention provides a high-speed motor cooling device based on a ring-shaped, non-powered heat pipe, which is directly mounted on the compressor housing to cool the magnetic levitation motor and magnetic bearings inside the compressor housing. Independent of the heat pump refrigerant circulation, it enables motor temperature control, ensuring the internal evaporation temperature of the motor is lower than the evaporation temperature of the high-temperature heat pump system. While ensuring motor safety, it significantly reduces the temperature of the motor coils and rotor, extending motor life and improving motor efficiency.

[0016] The cooling device utilizes a closed-loop heat pipe consisting of four parts: the motor cavity, the exhaust pipe, the condenser assembly, and the return pipe. Liquid refrigerant enters the compressor housing through the return pipe. Upon contact with heat-generating components (such as coils, rotors, and magnets) in the motor cavity, it absorbs heat and evaporates into a gaseous state. The gaseous refrigerant, due to its decreasing density from heat, flows out of the motor cavity via natural convection, rises along the exhaust pipe, and enters the condenser assembly located above the compressor. A fan outside the condenser assembly generates forced convection, using ambient temperature to cool the condenser assembly. The gaseous refrigerant releases heat within the condenser assembly, condenses, and liquefies. Under gravity, it flows along the condenser assembly to the condensate storage chamber and then back into the motor cavity, completing the cycle. This forms a closed-loop heat pipe. The evaporation and vaporization of the refrigerant within the motor cavity absorbs heat, thus cooling the motor and ensuring it operates within a safe temperature range. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model.

[0018] Figure 2 This is a schematic diagram of the cooling mechanism in this utility model.

[0019] Figure 3 This is a schematic diagram of the cooling mechanism in this utility model that does not include heat dissipation fins.

[0020] Figure 4 This is a schematic diagram of the main structure of this utility model.

[0021] Figure 5 This is a schematic diagram illustrating the working principle of the Chinese-language Tube of this utility model.

[0022] The components are: 1. Compressor housing, 2. Seals, 3. Stator, 4. Rotor, 5. Front bearing, 6. Rear bearing, 7. Thrust bearing, 8. Protective bearing, 9. Compressor impeller, 10. Exhaust pipe, 11. Condenser pipe, 12. Return pipe, 13. Venturi ejector, 14. Liquid inlet pipe, 15. Air inlet, 16. Injector, 17. Fan, 18. Gas distributor, 19. Liquid storage chamber, 20. Heat dissipation fins. Detailed Implementation

[0023] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be clearly and completely described below in conjunction with specific embodiments.

[0024] like Figure 1 and Figure 4The high-speed motor cooling device based on a ring-shaped non-powered heat pipe is shown. It includes a compressor and a cooling mechanism disposed outside the compressor. The cooling mechanism includes an exhaust pipe 10 and a return pipe 12 connected to the compressor housing 1. The connection positions of the exhaust pipe 10 and the return pipe 12 to the compressor housing 1 are respectively located on both sides of the stator 3 in the axial direction. The inner wall of the compressor housing 1 is provided with a Venturi ejector tube 13 connected to the return pipe 12. The outer ends of the exhaust pipe 10 and the return pipe 12 are connected to a condenser assembly.

[0025] The high-temperature heat pump system consists of a compressor, evaporator, condenser, and expansion valve. This application aims to cool the magnetic levitation motor in the compressor. The high-speed motor cooling device is directly installed on the compressor housing 1 to cool the magnetic levitation motor and magnetic bearings inside the compressor housing 1. Independent of the heat pump refrigerant circulation, it enables motor temperature control, ensuring that the internal evaporation temperature of the motor is lower than the evaporation temperature of the high-temperature heat pump system. While ensuring motor safety, this significantly reduces the temperature of the motor coils and rotor, extending motor life and improving motor efficiency.

[0026] The cooling device utilizes a closed-loop heat pipe consisting of four parts: the motor cavity, the exhaust pipe 10, the condenser assembly, and the return pipe 12. Liquid refrigerant enters the compressor housing 1 through the return pipe 12. Upon contact with heat-generating components (such as coils, rotors, and magnets) in the motor cavity, it absorbs heat and evaporates into a gaseous state. The gaseous refrigerant, due to its reduced density from the heat, flows out of the motor cavity via natural convection, rises along the exhaust pipe 10, and enters the condenser assembly located above the compressor. A fan 17 outside the condenser assembly generates forced convection, using ambient temperature to cool the condenser assembly. The gaseous refrigerant releases heat within the condenser assembly, condenses, and liquefies. Under gravity, it flows along the condenser assembly to the condensate storage chamber 19, and then flows back into the motor cavity to complete the cycle, thus forming a closed-loop heat pipe. The evaporation and vaporization of the refrigerant within the motor cavity absorbs heat, thereby cooling the motor and ensuring it operates within a safe temperature range.

[0027] like Figure 2 and Figure 3 As shown, the condensation assembly includes multiple horizontally arranged and inclined condenser tubes 11. The two ends of the condenser tubes 11 are connected to the exhaust pipe 10 and the return pipe 12, respectively, and the end of the condenser tube 11 connected to the exhaust pipe 10 is higher than the end of the condenser tube 11 connected to the return pipe 12.

[0028] As a further optimization, heat dissipation fins 20 are provided on the outside of the condenser tube 11; a fan 17 is installed on the compressor housing 1 below the condenser tube 11 to blow air toward the condenser tube 11, and the fan 17 is used to cool the condenser tube 11.

[0029] like Figure 5As shown in this embodiment, the Venturi ejector 13 is generally arc-shaped to fit the contour of the inner wall of the compressor housing 1. An air inlet 15 and an injection port 16 are respectively provided at both ends of the Venturi ejector 13. The air inlet 15 faces the rotation direction of the rotor 4, and the injection port 16 faces the rotation direction of the rotor 4. The middle part of the Venturi ejector 13 is connected to the return pipe 12 through a liquid inlet pipe 14, which is located at the top of the Venturi ejector 13. The air inlet 15, liquid inlet 14, and injection port 16 are connected. Designing the Venturi ejector 13 as an arc shape serves two purposes: firstly, it adapts to the inner wall of the compressor housing 1, facilitating stable installation; secondly, since the airflow in the motor cavity rotates in a circular motion under the drive of the rotor 4, the arc shape of the Venturi ejector 13 ensures that the air inlet 15 and the injection port 16 correspond to the flow direction of the airflow in the motor cavity, which is beneficial for the operation of the Venturi ejector 13.

[0030] After the liquid refrigerant enters the motor cavity, in order to fully atomize it into numerous small droplets, maximize its specific surface area, and increase the contact area with the motor's heating surface, a Venturi ejector is designed at the position where the liquid refrigerant enters the motor cavity, i.e., at the liquid inlet pipe 14, corresponding to the rotation direction of the motor rotor 4. When the high-speed rotating gaseous refrigerant in the motor cavity passes through the air inlet 15 of the Venturi ejector pipe 13, a local low pressure is formed in the acceleration section, the flow rate increases and the pressure decreases, thereby creating a pressure difference on the liquid refrigerant flowing down the liquid inlet pipe 14, which plays an ejecting role and achieves full mixing of the gaseous and liquid refrigerant. During the mixing process, the liquid refrigerant is fully atomized.

[0031] like Figure 4 As shown, in this embodiment, the compressor includes a compressor housing 1 and a rotor 4 disposed within the compressor housing 1. The end of the rotor 4 is connected to a compression impeller 9. A stator 3 is disposed in the middle of the inner wall of the compressor housing 1. A front bearing 5 and a rear bearing 6 are respectively disposed at the front and rear ends of the stator 3. The connection positions of the exhaust pipe 10 and the return pipe 12 to the compressor housing 1 are located outside the front bearing 5 and the rear bearing 6, respectively. Both the front bearing 5 and the rear bearing 6 are magnetic levitation bearings. The gap between the stator 3 and the magnetic levitation bearings and the rotor 4 forms an annular gas flow channel. The two ends of the gas flow channel are connected to the exhaust pipe 10 and the return pipe 12, respectively. The stator 3, rotor 4, magnetic levitation bearings, etc., inside the compressor housing 1 constitute a magnetic levitation motor. The motor cavity mentioned in this article refers to the internal cavity of the magnetic levitation motor, and the cooling medium flows in the gas flow channel inside the motor cavity.

[0032] The exhaust pipe 10 and return pipe 12 are vertically arranged, with the exhaust pipe 10 being higher than the return pipe 12. A gas distributor 18 and a liquid storage chamber 19 are respectively installed at the upper ends of the exhaust pipe 10 and the return pipe 12. The condenser pipe 11 includes a straight section in the middle and bent sections at both ends, with the two ends of the condenser pipe 11 connected to the gas distributor 18 and the liquid storage chamber 19 via the bent sections. The gas distributor 18 is a hollow cavity that buffers and diverts the gas flow.

[0033] The heat dissipation fins 20 include a plurality of evenly arranged fins, which are perpendicular to the axial direction of the straight pipe section. The fins are arranged side by side along the length of the straight pipe section of the condenser pipe 11. The heat dissipation fins 20 are provided with through holes corresponding to each straight pipe section. In this embodiment, the heat dissipation fins 20 are corrugated fins. The refrigerant is Freon.

[0034] The cooling device is suitable for compressors with single-sided impellers and double-sided impellers, such as... Figure 4 As shown, taking a compressor with a single impeller as an example, a thrust bearing 7 is provided at the rear end of the rear bearing 6 inside the compressor housing 1, and protective bearings 8 are provided on both the front bearing 5 and the rear bearing 6 side inside the compressor housing 1. A seal 2 is also provided between the tail end of the compression impeller 9 and the compressor housing 1.

[0035] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high speed electric machine cooling device based on a looped unpowered heat pipe, characterized by: It includes a compressor and a cooling mechanism located outside the compressor. The cooling mechanism includes an exhaust pipe (10) and a return pipe (12) connected to the compressor housing (1). The connection positions of the exhaust pipe (10) and the return pipe (12) to the compressor housing (1) are located on both sides of the stator (3). The inner wall of the compressor housing (1) is provided with a Venturi ejector (13) connected to the return pipe (12). The outer ends of the exhaust pipe (10) and the return pipe (12) are connected to the condenser assembly.

2. A high speed electric machine cooling device based on a looped unpowered heat pipe according to claim 1, characterized in that: The condensation assembly includes multiple condenser tubes (11) arranged side by side at an angle. The two ends of the condenser tubes (11) are connected to the exhaust pipe (10) and the return pipe (12) respectively, and the end of the condenser tube (11) connected to the exhaust pipe (10) is higher than the end of the condenser tube (11) connected to the return pipe (12).

3. A high speed electric machine cooling device based on looped unpowered heat pipe according to claim 2, characterized in that: The condenser tube (11) is provided with heat dissipation fins (20) on the outside; a fan (17) is provided below the condenser tube (11) to blow air toward the condenser tube (11).

4. A high speed electric machine cooling device based on looped unpowered heat pipe according to claim 3, characterized in that: The Venturi ejector tube (13) is an arc shape that matches the inner wall contour of the compressor housing (1). The Venturi ejector tube (13) has an air inlet (15) and an injection port (16) at both ends. The air inlet (15) faces the rotation direction of the rotor (4), and the injection port (16) faces the rotation direction of the rotor (4). The middle part of the Venturi ejector tube (13) is connected to the return pipe (12).

5. A high speed electric machine cooling device based on looped unpowered heat pipe according to claim 4, characterized in that: The compressor includes a compressor housing (1) and a rotor (4) disposed inside the compressor housing (1). The end of the rotor (4) is connected to a compression impeller (9). A stator (3) is disposed in the middle of the inner wall of the compressor housing (1). A front bearing (5) and a rear bearing (6) are respectively disposed at the front and rear ends of the stator (3). The connection positions of the exhaust pipe (10) and the return pipe (12) with the compressor housing (1) are located outside the front bearing (5) and the rear bearing (6), respectively.

6. A high speed electric machine cooling device based on looped unpowered heat pipe according to claim 5, characterized in that: The front bearing (5) and the rear bearing (6) are both magnetic levitation bearings. The gap between the stator (3) and the magnetic levitation bearing and the rotor (4) forms an annular gas flow channel. The two ends of the gas flow channel are connected to the exhaust pipe (10) and the return pipe (12) respectively.

7. A high speed electric machine cooling device based on looped unpowered heat pipe according to claim 3, characterized in that: The exhaust pipe (10) and return pipe (12) are vertically arranged, and the height of the exhaust pipe (10) is higher than the height of the return pipe (12). The upper ends of the exhaust pipe (10) and return pipe (12) are respectively provided with a gas distributor (18) and a liquid storage chamber (19). The condenser pipe (11) includes a straight pipe section in the middle and a bent pipe section at both ends. The two ends of the condenser pipe (11) are connected to the gas distributor (18) and the liquid storage chamber (19) through the bent pipe sections.

8. A high speed electric machine cooling device based on looped unpowered heat pipe according to claim 7, characterized in that: The heat dissipation fins (20) include a plurality of fins evenly arranged, the fins being perpendicular to the axial direction of the straight pipe section and arranged side by side along the length of the straight pipe section of the condenser tube (11). The heat dissipation fins (20) are provided with through holes corresponding to each straight pipe section.

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