Air compressor compression cooling and expansion heat preservation structure and temperature control method

Abstract

The application provides an air compressor compression cooling and expansion heat preservation structure and a temperature control method, which comprises a cooling channel, a heat preservation channel and a plurality of valves and temperature sensors; when each pipeline of the cooling channel works, cooling water is introduced from a main water inlet pipeline and is branched, a part of the cooling water flows through a first branch pipeline, a first water inlet channel, a first back plate cooling flow channel, a first return pipeline and a first main return pipeline, and the other part of the cooling water flows through a motor water inlet pipeline, a motor cooling water channel, a motor water outlet pipeline and the first main return pipeline; when each pipeline of the heat preservation channel works, return cooling water is branched through the first main return pipeline; when the air compressor works, the opening and closing of each valve of the cooling channel and the heat preservation channel are controlled according to the temperatures of a compression end volute, a motor, return cooling water and an expansion end volute; and the application solves the problem of waste heat utilization of turbine air compressor motor return cooling water of an integrated expander, and improves the operation efficiency of the integrated expander turbine air compressor.

Description

Technical Field

[0001] This invention relates to the field of air compressor technology, and in particular to an air compressor compression cooling and expansion insulation structure and temperature control method. Background Technology

[0002] Hydrogen is an ideal energy source, with high calorific value, no pollution, and wide availability, while fuel cells are considered an energy converter for hydrogen energy.

[0003] Fuel cells have advantages such as high energy conversion efficiency, zero emissions, and no noise, making them key to supporting a low-carbon and clean development model. To ensure the normal operation of fuel cells, an air compressor is needed to provide compressed air with a certain mass flow rate. As the power of fuel cells continues to increase, the pressure and flow rate of the supplied air also increase significantly, and the parasitic power of the air compressor also increases. To develop air compressors with higher power levels, the current mainstream technical route is to use air compressors with turbine energy recovery. This utilizes the principle of turbine expansion to recover and reuse the high-temperature and high-pressure exhaust gas discharged from the fuel cell stack, thereby improving the efficiency of the air compressor.

[0004] Turbine air compressors with integrated expanders recover exhaust gas from fuel cells through expansion, but the adiabatic efficiency decreases due to the drop in gas temperature during expansion. Insulating the turbine air compressor reduces temperature loss and improves adiabatic efficiency, thereby increasing expansion recovery efficiency and energy utilization. Currently, in turbine air compressors with integrated expanders, preheating at the expansion end mainly involves introducing the heated gas (after cooling the internal components of the compressor casing) into the volute preheating chamber. However, this preheating method has the following main drawbacks:

[0005] (1) The gas flows from the stator and rotor inside the motor housing, then through the gap between the expansion end bearing seat and the rotor, and then through the guide into the expansion end volute preheating chamber to preheat the volute. The gas flows a long way and there is a large resistance when passing through the gap, which leads to an increase in the power consumption of the cooling system.

[0006] (2) Because air has a small heat capacity, a unit mass of air can only store a small amount of heat. At the same time, because air has a small thermal conductivity, heat is difficult to transfer quickly. This means that it takes longer to transfer heat to the volute casing of the compression end, thereby raising its temperature.

[0007] (3) Due to the complex operating conditions of the air compressor, the temperature of the return medium of the cooling system will also change. However, for the heating of the expansion end volute, it is necessary to ensure that the temperature of the return medium of the cooling system is higher than the temperature of the gas inside the expansion end volute, so as to achieve the heat preservation effect.

[0008] When a turbo air compressor with an integrated expander compresses gas, the gas pressure and temperature increase. However, excessively high gas temperature leads to a decrease in gas density, thereby reducing the compressor's compression efficiency. To prevent excessively high gas temperatures, a suitable flow channel can be designed into the compression chamber to introduce a cooling medium, thereby reducing the gas temperature, lowering compression power consumption, and improving thermal efficiency. However, current research on cooling compression in air compressors with a compression-expansion configuration is limited, and there is no effective solution to the aforementioned problems.

[0009] In summary, there is an urgent need to design a cooling and insulation structure and a suitable temperature control method for integrated expander turbo air compressors that can reduce compression power consumption and improve expansion efficiency. Summary of the Invention

[0010] This invention proposes a compression cooling and expansion insulation structure and temperature control method for an air compressor. Through sequentially connected internal and external cooling and insulation channels, a biomimetic flow channel backplate, a spiral flow channel volute design, and the installation of temperature sensors and various valves, it solves the problems of lack of cooling and high compression power consumption in integrated expander turbo air compressors, low energy recovery efficiency due to heat loss during expansion, and the utilization of waste heat from the motor's return cooling water. This improves the operating efficiency of the integrated expander turbo air compressor.

[0011] The present invention adopts the following technical solution.

[0012] An air compressor compression cooling and expansion insulation structure includes a cooling channel, an insulation channel, and multiple valves and temperature sensors for controlling the cooling channel and the insulation channel;

[0013] When the cooling channels are in operation, the cooling water is introduced through the main inlet pipe (5) and then diverted. Part of the cooling water flows through the first diversion pipe (6), the first inlet channel (7), the first back plate cooling channel (8), the first return pipe (15), and the first main return pipe (32), while the other part of the cooling water flows through the motor inlet pipe (31), the motor cooling water channel (12), the motor outlet pipe (16), and the first main return pipe (32).

[0014] When the pipes in the insulation channel are working, the heated cooling water is used as return cooling water and is diverted again through the first main return pipe (32). Part of the return cooling water flows through the second diversion pipe (17), the second inlet channel (18), the second back plate insulation channel (19), the second return pipe (20), and the second main return pipe (27), while the other part of the return cooling water flows through the third diversion pipe (22), the volute insulation channel (24), the third return pipe (26), and the second main return pipe (27).

[0015] The first backplate cooling channel is located at the first backplate (4), and the second backplate insulation channel is located at the second backplate (33).

[0016] When the air compressor is working, it controls the opening and closing of various valves in the cooling channel and the insulation channel based on the temperature of the compression end volute, motor, return cooling water and expansion end volute measured by the temperature sensor.

[0017] The first branch pipe, the first return pipe, the first main return pipe, the second branch pipe, the third branch pipe, the third return pipe, the second return pipe, and the second main return pipe are all located outside the air compressor housing to save internal space and avoid energy loss of cooling water.

[0018] The first and second water inlet channels are both located on the air compressor housing near the volute side, and are used to directly introduce cooling water into the corresponding channels.

[0019] The air compressor has a large arc pipe structure at the bifurcation point between the main water inlet pipe and the first branch pipe, and a first electromagnetic throttle valve (100) is installed on the first branch pipe.

[0020] The first electromagnetic throttle valve controls the flow rate of cooling water based on the temperature of the volute at the compression end measured by the first temperature sensor (102), thereby effectively controlling the air temperature inside the volute at the compression end (1) and reducing compression power consumption.

[0021] The internal flow channel structure of the first back plate cooling channel is a leaf vein-shaped bionic flow channel. Cooling water is introduced into the main flow channel (52) of the leaf vein-shaped bionic flow channel through the inlet (50). Cooling water is diverted by the ribs (51) of the leaf vein-shaped bionic flow channel and introduced into the branch flow channel (54) of the leaf vein-shaped bionic flow channel to improve the uniformity of cooling water distribution and increase the heat exchange area.

[0022] Cooling water from the main channel of the leaf vein-shaped bionic flow channel passes through the circular flow channel (53) of the middle leaf vein-shaped bionic flow channel, and is collected by the branch channel cooling water from the annular collection channel (55) of the leaf vein-shaped bionic flow channel, and is discharged together through the outlet (56) of the leaf vein-shaped bionic flow channel.

[0023] The first back plate is close to the compressor end impeller (2) on one side, and the cooling water flowing inside the first back plate absorbs the heat generated when the compressed gas is compressed. The other side of the first back plate is close to the compressor end bearing seat (10).

[0024] The second back plate has one side close to the impeller at the expansion end and the other side close to the bearing housing at the expansion end. The second back plate uses the reflux cooling water inside the second back plate to keep the expansion process at the expansion end warm, so as to reduce the temperature difference during the expansion process and improve the insulation efficiency.

[0025] Both the first back plate and the second back plate are provided with labyrinth-type sealing structures on their outer sides to prevent gas from the compression end and expansion end from leaking into the motor.

[0026] A second electromagnetic throttle valve (101) is installed on the motor water inlet pipe to control the flow rate of motor cooling water in the motor water inlet pipe according to the stator temperature of the motor.

[0027] The motor cooling water channel is spiral-shaped, and square grooves are opened inside the channel to change the flow state of the cooling water and improve the heat exchange efficiency.

[0028] The motor outlet water pipe is a motor cooling water outlet pipe inclined at a 45-degree angle; the first main return pipe is connected to the first return pipe and the motor outlet water pipe, and the cooling water flow direction is consistent with that of the first return pipe, so as to reduce the flow resistance of the motor return cooling water and collect the heated cooling water for waste heat utilization.

[0029] A third electromagnetic three-way valve (105) is installed at the first main return pipe. The upward opening of the valve is connected to the third main return pipe (34), and the right opening is connected to the first main return pipe (32) in another direction. Whether to utilize waste heat is determined based on the temperature difference between the return cooling water and the air outlet of the expansion end volute.

[0030] The second back plate has a second back plate heat insulation channel inside. The return cooling water enters the main channel (52) of the leaf vein-shaped bionic channel through the outlet (56) of the leaf vein-shaped bionic channel of the second back plate. It is divided by the leaf vein-shaped bionic channel ribs (51) on both sides. Part of the return cooling water flows through the branch channel (54) of the leaf vein-shaped bionic channel and flows into the inlet (50) of the leaf vein-shaped bionic channel from the outer leaf vein-shaped bionic channel annular collection channel (55). The other part flows into the inlet (50) of the leaf vein-shaped bionic channel after passing through the circular channel (53) of the leaf vein-shaped bionic channel. The temperature of the expansion process is increased through sufficient heat exchange.

[0031] The opening of the volute insulation channel is located on the expansion end volute (28) near the tip edge of the expansion end impeller (29). The volute insulation channel (24) is spirally opened inside the volute (28) around the air outlet of the expansion end volute (28) to improve heat exchange efficiency and reduce friction resistance. The return cooling water enters from the volute insulation channel inlet (23) above the air outlet of the expansion end volute, flows through the volute insulation channel and out from the volute insulation channel outlet (25) to reduce the temperature difference between the inlet and outlet of the expansion end and improve the expansion efficiency.

[0032] The second main return pipe (27) is connected to the second return pipe (20) and the third return pipe (26) and is used to collect return cooling water.

[0033] The inner wall of the compression end volute, the surface of the motor stator, the first main return pipe, and the inner wall of the expansion end volute outlet are respectively equipped with a first temperature sensor (102), a second temperature sensor (103), a third temperature sensor (104), and a fourth temperature sensor (106).

[0034] A temperature control method for the compression cooling and expansion insulation structure of an air compressor, wherein the temperature control method is an open-loop control, and controls each solenoid valve by acquiring the temperatures of a first temperature sensor, a second temperature sensor, a third temperature sensor, and a fourth temperature sensor, including:

[0035] Method A: The first solenoid valve of the first diversion pipe is controlled in three levels according to the temperature of the volute at the compression end. When the temperature of the volute at the compression end is lower than the working temperature threshold of the first volute, the throttle valve of the first solenoid valve is slightly opened to supply a small flow of cooling water for cooling. When the temperature of the volute at the compression end is higher than the working temperature threshold of the first volute but lower than the working temperature threshold of the second volute, the throttle valve of the first solenoid valve is half-opened to supply a medium flow of cooling water for cooling. When the temperature of the volute at the compression end is higher than the working temperature threshold of the second volute, the throttle valve of the first solenoid valve is fully opened to supply a large flow of cooling water for cooling.

[0036] Method B: The second solenoid valve of the motor water inlet pipe is controlled in three stages according to the stator temperature. When the stator temperature is less than the first motor operating temperature threshold, the second solenoid throttle valve is slightly open to supply a small flow of cooling water for cooling. When the stator temperature is greater than the first motor operating temperature threshold but less than the second motor operating temperature threshold, the second solenoid throttle valve is half open to supply a medium flow of cooling water for cooling. When the stator temperature is greater than the second motor operating temperature threshold, the second solenoid throttle valve 101 is fully open to supply a large flow of cooling water for cooling.

[0037] Method C: When the indicated temperature of the first temperature sensor is within the dead zone temperature range of the volute, the current temperature control strategy is executed to prevent the control strategy from frequently switching when the temperature approaches the first volute operating temperature threshold and the second volute operating temperature threshold. When the indicated temperature of the second temperature sensor is within the dead zone temperature range of the motor, the current temperature control strategy is executed to prevent the control strategy from frequently switching when the temperature approaches the first motor operating temperature threshold and the second motor operating temperature threshold.

[0038] Method D: Based on the temperature difference between the return cooling water in the first main return pipe and the air outlet (28) of the expansion end volute, the third electromagnetic three-way valve on the first main return pipe is controlled in two ways. When the temperature difference is positive, the upward outlet of the third electromagnetic three-way valve is closed and the right outlet is opened, and the return cooling water flows into the expansion end for heat preservation. When the temperature difference is negative, the upward outlet of the third electromagnetic three-way valve is opened and the right outlet is closed, and the return cooling water flows into the third main return pipe without heat preservation of the expansion end.

[0039] The present invention adopts the above-described solution and has the following advantages:

[0040] 1. By creating a vein-shaped biomimetic flow channel inside the back plate behind the impeller at the compression end, the heat generated by compression can be effectively reduced. This structure consists of two parts: a main channel and a branch channel. The main channel connects the cooling water inlet and outlet and has a circular structure in the middle, while the branch channel is used to deliver cooling water to areas far away from the main channel. Specifically, 12 veins are set on both sides of the main channel to improve the uniformity of cooling water distribution, reduce the pressure drop in the flow channel, and ensure the cooling effect.

[0041] 2. By setting up a cooling water return pipe, the return cooling water from the compressor end and the return cooling water from the motor are collected into the first main return pipe to recover the heat of the heated cooling water. Part of the return cooling water is introduced into the second back plate insulation channel, and the other part of the return cooling water flows into the spiral insulation channel of the volute through the third branch pipe. The expansion end is insulated from two parts to reduce heat loss and improve expansion efficiency.

[0042] 3. By using temperature sensors installed on the inner wall of the compression end volute, the surface of the motor stator, the first main return pipe, and the inner wall of the expansion end volute outlet, as well as valves on the first branch pipe, the motor inlet pipe, and the first main return pipe, it is possible to achieve efficient cooling of the compression chamber and the motor and precise control of the return cooling water temperature based on the temperature. Attached Figure Description

[0043] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0044] Appendix Figure 1 This is a cross-sectional structural schematic diagram of the present invention;

[0045] Appendix Figure 2 This is a schematic diagram of a three-dimensional model of the leaf vein-shaped biomimetic flow channel structure inside the back plate of the present invention;

[0046] Appendix Figure 3 This is a schematic diagram of the temperature control method of the present invention;

[0047] In the diagram: 1. Compression end volute, 2. Compression end impeller, 3. Compression end volute, 4. First back plate, 5. Main water inlet pipe, 6. First branch pipe, 7. First water inlet channel, 8. First back plate cooling channel, 9. Labyrinth-type sealing structure.

[0048] 10. Compressor end bearing housing; 11. Air compressor housing; 12. Motor cooling water channel; 13. Stator; 14. Rotor; 15. First return flow pipe; 16. Motor outlet water pipe; 17. Second branch pipe; 18. Second water inlet channel; 19. Second back plate insulation channel.

[0049] 20. Second return pipe; 21. Expansion end bearing housing; 22. Third branch pipe; 23. Inlet of volute insulated flow channel; 24. Volute insulated flow channel; 25. Outlet of volute insulated flow channel; 26. Third return pipe; 27. Second main return pipe; 28. Expansion end volute; 29. ​​Expansion end impeller.

[0050] 30. Expansion end worm gear; 31. Motor inlet pipe; 32. First main return pipe; 33. Second back plate; 34. Third main return pipe.

[0051] 50. Leaf vein-shaped bionic flow channel inlet; 51. Leaf vein-shaped bionic flow channel ribs; 52. Leaf vein-shaped bionic flow channel main channel; 53. Leaf vein-shaped bionic flow channel circular channel; 54. Leaf vein-shaped bionic flow channel branch channel; 55. Leaf vein-shaped bionic flow channel annular collection channel; 56. Leaf vein-shaped bionic flow channel outlet.

[0052] 100. First electromagnetic throttle valve; 101. Second electromagnetic throttle valve; 102. First temperature sensor; 103. Second temperature sensor; 104. Third temperature sensor; 105. Third electromagnetic three-way valve; 106. Fourth temperature sensor. Detailed Implementation

[0053] As shown in the figure, an air compressor compression cooling and expansion insulation structure includes a cooling channel, an insulation channel, and multiple valves and temperature sensors for controlling the cooling channel and the insulation channel.

[0054] When the cooling channels are in operation, the cooling water is introduced through the main inlet pipe 5 and then divided. A portion of the cooling water flows through the first branch pipe 6, the first inlet channel 7, the first backplate cooling channel 8, the first return pipe 15, and the first main return pipe 32. The other portion of the cooling water flows through the motor inlet pipe 31, the motor cooling water channel 12, the motor outlet pipe 16, and the first main return pipe 32.

[0055] When the pipes in the insulation channel are working, the heated cooling water is used as return cooling water and is diverted again through the first main return pipe 32. Part of the return cooling water flows through the second diversion pipe 17, the second inlet channel 18, the second back plate insulation channel 19, the second return pipe 20, and the second main return pipe 27, while the other part of the return cooling water flows through the third diversion pipe 22, the volute insulation channel 24, the third return pipe 26, and the second main return pipe 27.

[0056] The first backplate cooling channel is located at position 4 on the first backplate, and the second backplate insulation channel is located at position 33 on the second backplate.

[0057] When the air compressor is working, it controls the opening and closing of various valves in the cooling channel and the insulation channel based on the temperature of the compression end volute, motor, return cooling water and expansion end volute measured by the temperature sensor.

[0058] The first branch pipe, the first return pipe, the first main return pipe, the second branch pipe, the third branch pipe, the third return pipe, the second return pipe, and the second main return pipe are all located outside the air compressor housing to save internal space and avoid energy loss of cooling water.

[0059] The first and second water inlet channels are both located on the air compressor housing near the volute side, and are used to directly introduce cooling water into the corresponding channels.

[0060] The air compressor's main water inlet pipe and the first branch pipe are bifurcated at a large arc pipe structure, and a first electromagnetic throttle valve 100 is installed on the first branch pipe.

[0061] The first electromagnetic throttle valve controls the flow rate of cooling water based on the temperature of the compression end volute measured by the first temperature sensor 102, thereby effectively controlling the air temperature inside the compression end volute 1 and reducing compression power consumption.

[0062] The internal flow channel structure of the first back plate cooling channel is a leaf vein-shaped bionic flow channel. Cooling water is introduced into the main flow channel 52 of the leaf vein-shaped bionic flow channel through the inlet 50. Cooling water is diverted by the ribs 51 of the leaf vein-shaped bionic flow channel and introduced into the branch flow channel 54 of the leaf vein-shaped bionic flow channel to improve the uniformity of cooling water distribution and increase the heat exchange area.

[0063] Cooling water from the main channel of the leaf vein-shaped bionic flow channel passes through the central circular flow channel 53 of the leaf vein-shaped bionic flow channel, and is collected by the branch channel cooling water from the annular collection channel 55 of the leaf vein-shaped bionic flow channel, and is discharged together through the outlet 56 of the leaf vein-shaped bionic flow channel.

[0064] The first back plate is close to the compressor end impeller 2 on one side, and the cooling water flowing inside the first back plate absorbs the heat generated when the compressed gas is compressed. The other side of the first back plate is close to the compressor end bearing seat 10.

[0065] The second back plate has one side close to the impeller at the expansion end and the other side close to the bearing housing at the expansion end. The second back plate uses the reflux cooling water inside the second back plate to keep the expansion process at the expansion end warm, so as to reduce the temperature difference during the expansion process and improve the insulation efficiency.

[0066] Both the first back plate and the second back plate are provided with labyrinth-type sealing structures 9 on their outer sides to prevent gas from the compression end and expansion end from leaking into the motor.

[0067] A second electromagnetic throttle valve 101 is installed on the motor water inlet pipe to control the flow rate of motor cooling water in the motor water inlet pipe according to the stator temperature of the motor.

[0068] The motor cooling water channel is spiral-shaped, and square grooves are opened inside the channel to change the flow state of the cooling water and improve the heat exchange efficiency.

[0069] The motor outlet water pipe is a motor cooling water outlet pipe inclined at a 45-degree angle; the first main return pipe is connected to the first return pipe and the motor outlet water pipe, and the cooling water flow direction is consistent with that of the first return pipe, so as to reduce the flow resistance of the motor return cooling water and collect the heated cooling water for waste heat utilization.

[0070] A third electromagnetic three-way valve 105 is installed at the first main return pipe. The upward opening of the valve is connected to the third main return pipe 34, and the right opening is connected to the first main return pipe 32 in another direction. Whether to utilize waste heat is determined based on the temperature difference between the return cooling water and the air outlet of the expansion end volute.

[0071] The second back plate has a second back plate heat insulation channel inside. The return cooling water enters the main channel 52 of the leaf vein-shaped bionic channel through the outlet 56 of the leaf vein-shaped bionic channel on the second back plate. It is then divided by the leaf vein-shaped bionic channel ribs 51 on both sides. Part of the return cooling water flows into the leaf vein-shaped bionic channel inlet 50 through the branch channel 54 of the leaf vein-shaped bionic channel and the annular collection channel 55 of the outer leaf vein-shaped bionic channel. The other part flows into the leaf vein-shaped bionic channel inlet 50 after passing through the circular channel 53 of the leaf vein-shaped bionic channel. The expansion process temperature is increased through sufficient heat exchange.

[0072] The opening of the volute insulation channel is located on the expansion end volute 28 near the tip edge of the blade of the expansion end impeller 29. The volute insulation channel 24 is spirally opened inside the expansion end volute 28 around the air outlet of the expansion end volute 28 to improve heat exchange efficiency and reduce friction resistance. The return cooling water enters from the volute insulation channel inlet 23 above the air outlet of the expansion end volute, flows through the volute insulation channel and out from the volute insulation channel outlet 25 to reduce the temperature difference between the inlet and outlet of the expansion end and improve the expansion efficiency.

[0073] The second main return pipe 27 is connected to the second return pipe 20 and the third return pipe 26, and is used to collect return cooling water.

[0074] The inner wall of the compression end volute 30, the surface of the motor stator, the first main return pipe, and the inner wall of the expansion end volute outlet are respectively equipped with a first temperature sensor 102, a second temperature sensor 103, a third temperature sensor 104, and a fourth temperature sensor 106.

[0075] A temperature control method for the compression cooling and expansion insulation structure of an air compressor, wherein the temperature control method is an open-loop control, and controls each solenoid valve by acquiring the temperatures of a first temperature sensor, a second temperature sensor, a third temperature sensor, and a fourth temperature sensor, including:

[0076] Method A: The first solenoid valve of the first diversion pipe is controlled in three stages according to the temperature of the volute 3 at the compression end. When the temperature of the volute at the compression end is lower than the working temperature threshold of the first volute, the throttle valve of the first solenoid valve is slightly opened to supply a small flow of cooling water for cooling. When the temperature of the volute at the compression end is greater than the working temperature threshold of the first volute but less than the working temperature threshold of the second volute, the throttle valve of the first solenoid valve is half-opened to supply a medium flow of cooling water for cooling. When the temperature of the volute at the compression end is greater than the working temperature threshold of the second volute, the throttle valve of the first solenoid valve is fully opened to supply a large flow of cooling water for cooling.

[0077] Method B: The second solenoid valve of the motor water inlet pipe is controlled in three stages according to the stator temperature. When the stator temperature is less than the first motor operating temperature threshold, the second solenoid throttle valve is slightly open to supply a small flow of cooling water for cooling. When the stator temperature is greater than the first motor operating temperature threshold but less than the second motor operating temperature threshold, the second solenoid throttle valve is half open to supply a medium flow of cooling water for cooling. When the stator temperature is greater than the second motor operating temperature threshold, the second solenoid throttle valve 101 is fully open to supply a large flow of cooling water for cooling.

[0078] Method C: When the indicated temperature of the first temperature sensor is within the dead zone temperature range of the volute, the current temperature control strategy is executed to prevent the control strategy from frequently switching when the temperature approaches the first volute operating temperature threshold and the second volute operating temperature threshold. When the indicated temperature of the second temperature sensor is within the dead zone temperature range of the motor, the current temperature control strategy is executed to prevent the control strategy from frequently switching when the temperature approaches the first motor operating temperature threshold and the second motor operating temperature threshold.

[0079] Method D: Based on the temperature difference between the return cooling water in the first main return pipe and the air outlet 28 of the expansion end volute, the third electromagnetic three-way valve on the first main return pipe is controlled in two ways: when the temperature difference is positive, the upward outlet of the third electromagnetic three-way valve is closed and the right outlet is opened, and the return cooling water flows into the expansion end for heat preservation; when the temperature difference is negative, the upward outlet of the third electromagnetic three-way valve is opened and the right outlet is closed, and the return cooling water flows into the third main return pipe without heat preservation of the expansion end.

[0080] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An air compressor compression cooling and expansion insulation structure, characterized by: Includes cooling channels, insulation channels, and multiple valves and temperature sensors used to control the cooling channels and insulation channels; When the cooling channels are in operation, the cooling water is introduced through the main inlet pipe (5) and then diverted. Part of the cooling water flows through the first diversion pipe (6), the first inlet channel (7), the first back plate cooling channel (8), the first return pipe (15), and the first main return pipe (32), while the other part of the cooling water flows through the motor inlet pipe (31), the motor cooling water channel (12), the motor outlet pipe (16), and the first main return pipe (32). When the pipes in the insulation channel are working, the heated cooling water is used as return cooling water and is diverted again through the first main return pipe (32). Part of the return cooling water flows through the second diversion pipe (17), the second inlet channel (18), the second back plate insulation channel (19), the second return pipe (20), and the second main return pipe (27). The other part of the return cooling water flows through the third diversion pipe (22), the expansion end volute insulation channel (24), the third return pipe (26), and the second main return pipe (27). The first backplate cooling channel is located at the first backplate (4) inside the compression end volute, and the second backplate insulation channel is located at the second backplate (33) inside the expansion end volute. When the air compressor is working, it controls the opening and closing of various valves in the cooling channel and the heat preservation channel based on the temperature of the compression end volute, motor, return cooling water and expansion end volute measured by the temperature sensor. The first branch pipe, the first return pipe, the first main return pipe, the second branch pipe, the third branch pipe, the third return pipe, the second return pipe, and the second main return pipe are all located outside the air compressor housing to save internal space and avoid energy loss of cooling water. The first water inlet channel is located on the air compressor housing near the compression end volute, and the second water inlet channel is located on the air compressor housing near the expansion end volute for directly introducing cooling water into the corresponding flow channel.

2. The compression cooling and expansion insulation structure of claim 1, wherein: The air compressor has a large arc pipe structure at the bifurcation point between the main water inlet pipe and the first branch pipe, and a first electromagnetic throttle valve (100) is installed on the first branch pipe. The first electromagnetic throttle valve controls the flow rate of cooling water based on the temperature of the volute at the compression end measured by the first temperature sensor (102), thereby effectively controlling the air temperature inside the volute at the compression end (1) and reducing compression power consumption.

3. The compression cooling and expansion insulation structure of claim 1, wherein: The internal flow channel structure of the first back plate cooling channel is a leaf vein-shaped bionic flow channel. Cooling water is introduced into the main flow channel (52) of the leaf vein-shaped bionic flow channel through the inlet (50). Cooling water is diverted by the ribs (51) of the leaf vein-shaped bionic flow channel and introduced into the branch flow channel (54) of the leaf vein-shaped bionic flow channel to improve the uniformity of cooling water distribution and increase the heat exchange area. The cooling water flowing out from the main channel of the leaf vein-shaped bionic flow channel passes through the circular flow channel (53) of the leaf vein-shaped bionic flow channel in the middle of the first back plate, and together with the cooling water from the branch channel collected by the annular flow channel (55) of the leaf vein-shaped bionic flow channel at the edge of the first back plate, it is discharged through the outlet (56) of the leaf vein-shaped bionic flow channel.

4. The air compressor compression cooling and expansion insulation structure according to claim 1, characterized in that: The first back plate is close to the compressor end impeller (2) on one side, and the cooling water flowing inside the first back plate absorbs the heat generated when the compressed gas is compressed. The other side of the first back plate is close to the compressor end bearing seat (10). The second back plate has one side close to the impeller at the expansion end and the other side close to the bearing housing at the expansion end. The second back plate uses the reflux cooling water inside the second back plate to keep the expansion process at the expansion end warm, so as to reduce the temperature difference during the expansion process and improve the insulation efficiency. Both the first back plate and the second back plate are provided with labyrinth-type sealing structures on their outer sides to prevent gas from the compression end and expansion end from leaking into the motor.

5. The compression cooling and expansion insulation structure of claim 1, wherein: A second electromagnetic throttle valve (101) is installed on the motor water inlet pipe to control the flow rate of motor cooling water in the motor water inlet pipe according to the stator temperature of the motor. The motor cooling water channel is spiral-shaped, and square grooves are opened inside the channel to change the flow state of the cooling water and improve the heat exchange efficiency.

6. The compression cooling and expansion insulation structure of claim 1, wherein: The motor outlet water pipe is a motor cooling water outlet pipe inclined at a 45-degree angle; the first main return pipe is connected to the first return pipe and the motor outlet water pipe, and the cooling water flow direction is consistent with that of the first return pipe, so as to reduce the flow resistance of the motor return cooling water and collect the heated cooling water for waste heat utilization. A third electromagnetic three-way valve (105) is installed at the first main return pipe. The upward opening of the valve is connected to the third main return pipe (34), and the right opening is connected to the first main return pipe (32) in another direction. Whether to utilize waste heat is determined based on the temperature difference between the return cooling water and the air outlet of the expansion end volute.

7. The compression cooling and expansion insulation structure of claim 1, wherein: The second back plate has a second back plate heat insulation channel inside. The return cooling water enters the main channel (52) of the leaf vein-shaped bionic channel through the outlet (56) of the leaf vein-shaped bionic channel of the second back plate. It is divided by the leaf vein-shaped bionic channel ribs (51) on both sides. Part of the return cooling water flows through the branch channel (54) of the leaf vein-shaped bionic channel and flows into the inlet (50) of the leaf vein-shaped bionic channel from the outer leaf vein-shaped bionic channel annular collection channel (55). The other part flows into the inlet (50) of the leaf vein-shaped bionic channel after passing through the circular channel (53) of the leaf vein-shaped bionic channel. The temperature of the expansion process is increased through sufficient heat exchange. The opening of the volute insulation channel is located on the expansion end volute (28) near the tip edge of the expansion end impeller (29). The volute insulation channel (24) is spirally opened inside the volute (28) around the air outlet of the expansion end volute (28) to improve heat exchange efficiency and reduce friction resistance. The return cooling water enters from the volute insulation channel inlet (23) above the air outlet of the expansion end volute, flows through the volute insulation channel and out from the volute insulation channel outlet (25) to reduce the temperature difference between the inlet and outlet of the expansion end and improve the expansion efficiency. The second main return pipe (27) is connected to the second return pipe (20) and the third return pipe (26) and is used to collect return cooling water.

8. A temperature control method for an air compressor compression cooling and expansion insulation structure, employing the air compressor compression cooling and expansion insulation structure as described in any one of claims 1, 2, 3, 4, 5, 6, and 7, characterized in that: A first temperature sensor (102), a second temperature sensor (103), a third temperature sensor (104), and a fourth temperature sensor (106) are respectively installed on the inner wall of the volute at the compression end, the surface of the motor stator, the first main return pipe, and the inner wall of the air outlet at the expansion end of the volute. The temperature control method is an open-loop control, which controls each solenoid valve by acquiring the temperatures from the first, second, third, and fourth temperature sensors, including: Method A: The first electromagnetic throttle valve of the first diversion pipe is controlled in three stages according to the temperature of the volute at the compression end. When the temperature of the volute at the compression end is lower than the first working temperature threshold of the volute at the compression end, the throttle valve of the first electromagnetic throttle valve is slightly opened to supply a small flow of cooling water for cooling. When the temperature of the volute at the compression end is greater than the first working temperature threshold of the volute at the compression end but less than the second working temperature threshold of the volute at the compression end, the throttle valve of the first electromagnetic throttle valve is half-opened to supply a medium flow of cooling water for cooling. When the temperature of the volute at the compression end is greater than the second working temperature threshold of the volute at the compression end, the throttle valve of the first electromagnetic throttle valve is fully opened to supply a large flow of cooling water for cooling. Method B: The second electromagnetic throttle valve of the motor inlet pipe is controlled in three stages according to the stator temperature. When the stator temperature is less than the first motor operating temperature threshold of the air compressor motor, the second electromagnetic throttle valve is slightly opened to supply a small flow of cooling water for cooling. When the stator temperature is greater than the first motor operating temperature threshold and less than the second motor operating temperature threshold of the air compressor motor, the second electromagnetic throttle valve is half-open to supply a medium flow of cooling water for cooling. When the stator temperature is greater than the second motor operating temperature threshold of the air compressor motor, the second electromagnetic throttle valve (101) is fully open to supply a large flow of cooling water for cooling. Method C: When the indicated temperature of the first temperature sensor is within the dead zone temperature range of the volute, the current temperature control strategy is executed to prevent the control strategy from frequently switching when the temperature approaches the first volute operating temperature threshold and the second volute operating temperature threshold. When the indicated temperature of the second temperature sensor is within the dead zone temperature range of the motor, the current temperature control strategy is executed to prevent the control strategy from frequently switching when the temperature approaches the first motor operating temperature threshold and the second motor operating temperature threshold. Method D: Based on the temperature difference between the return cooling water in the first main return pipe and the air outlet (28) of the expansion end volute, the third electromagnetic three-way valve on the first main return pipe is controlled in two ways. When the temperature difference is positive, the upward outlet of the third electromagnetic three-way valve is closed and the right outlet is opened, and the return cooling water flows into the expansion end for heat preservation. When the temperature difference is negative, the upward outlet of the third electromagnetic three-way valve is opened and the right outlet is closed, and the return cooling water flows into the third main return pipe without heat preservation of the expansion end.

Images