An air compressor

Abstract

The present invention provides an air compressor, belonging to the technical field of air compressors. It solves the technical problem that the working flow of existing air compressors cannot meet the use requirements. The air compressor comprises a compression host and a motor for driving the compression host to work, the compression host comprises a casing and a screw shaft, the compression host has a plurality of compression hosts with the same displacement, and the screw shafts of the plurality of compression hosts are coaxially arranged and can rotate synchronously. The air compressor can quickly achieve the effect of doubling the volume displacement.

Description

Technical Field

[0001] The invention belongs to the technical field of air compressors and relates to an air compressor. Background Art

[0002] The single screw compressor consists of a cylindrical screw and two symmetrically arranged plane star wheels, which form a meshing pair and are installed in the casing. The screw groove, the inner wall of the casing (cylinder) and the star wheel teeth constitute a closed volume. The power is transmitted to the screw shaft, and the screw drives the star wheel to rotate. The gas enters the screw groove from the suction chamber and is discharged through the exhaust port and the exhaust chamber after being compressed. The role of the star wheel is equivalent to the piston of the reciprocating piston compressor. When the star wheel teeth move relatively in the screw groove, the closed volume gradually decreases and the gas is compressed.

[0003] A tandem multi-stage compressor is a form of screw compressor, which is widely used because of its compact structure and high transmission efficiency. For example, the inventor has previously developed a tandem multi-stage screw compressor without a shaft seal with application publication number CN102705238A, which includes a number of independent compression hosts connected in series. Each stage of the compression host has its own independent shell. The volume of each stage of the series compression host decreases from front to back. The screw shafts of adjacent compression hosts are connected and transmitted through a transmission connector. The shells of adjacent compression hosts are connected together through a seal. An oil return hole is provided at the bottom of the flange cylinder, and the oil return hole is connected to the air inlet of the previous stage host.

[0004] The compressor described above has a compact structure, and the applicant continues to research and develop on this basis, intending to further increase the working flow rate of the compressor. Summary of the invention

[0005] The present invention aims at the above-mentioned problems existing in the prior art and provides an air compressor. The technical problem to be solved by the present invention is: how to increase the working flow rate of the compression host.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] An air compressor comprises a compression main unit and a motor for driving the compression main unit to work, wherein the compression main unit comprises a casing and a screw shaft, and is characterized in that the compression main unit has a plurality of screw shafts with the same displacement, and the screw shafts of the plurality of compression main units are coaxially arranged and can rotate synchronously.

[0008] The compression host is an important working unit of the air compressor. It is generally driven by a motor. Its casing is equipped with components such as a star wheel and a screw. The outer surface of the screw has a screw groove that can mesh with the star wheel. The screw shaft is a component of the screw. The screw shaft can be connected to the motor to realize the operation of the compression host. Arranging several compression hosts with the same displacement coaxially is conducive to using the same motor to drive multiple compression hosts to work synchronously, ensuring that the working states of the two compression hosts are synchronized and consistent, and can quickly achieve the effect of doubling the volume displacement.

[0009] In the above-mentioned air compressor, the casing has an inner cylinder cavity for accommodating the screw shaft and a low-pressure cavity for accommodating the star wheel, and a support partition is provided in the inner cylinder cavity. The output end of the screw shaft is rotatably connected to the support partition, and the support partition can separate the inner cylinder cavity into a pressurized cavity for compressing air and a pressure isolation cavity that is only connected to the low-pressure cavity.

[0010] The inner cylinder cavity in the casing can accommodate the screw shaft to pass through, the low-pressure cavity accommodates the star wheel that cooperates with the screw and is connected with the end of the inner cylinder cavity close to the input end of the screw shaft to ensure smooth inhalation of low-pressure air, and the shape of the inner side wall of the inner cylinder cavity can be adapted to the outer peripheral surface of the screw. When the compression host is working, the screw shaft rotates to drive the meshing star wheel to rotate, and the air in the low-pressure cavity is sucked into the closed volume formed by the screw, the star wheel and the inner wall of the inner cylinder cavity and is gradually compressed. Finally, the high-pressure gas is discharged through the channel on the circumferential side wall of the inner cylinder cavity to realize the compression operation. The outer edge of the output end of the screw is adapted to the inner cylinder cavity. By arranging a supporting baffle in the inner cylinder cavity, the output end of the screw shaft is rotatably connected to the supporting baffle, and the inner cylinder cavity is divided into a pressurized chamber and a pressure-isolating chamber. The output end of the screw is located in the pressurized chamber, and the inner wall of the pressurized chamber can cooperate with the screw to realize air compression. At the same time, the pressure-isolating chamber is arranged at an adjacent position of the pressurized chamber along the axial direction of the screw shaft, and the pressure-isolating chamber is only connected to the low-pressure chamber. In this way, under the condition of ensuring normal compression work, the air entering the pressure-isolating chamber from between the screw and the inner wall of the pressurized chamber can enter the low-pressure area, so that the inner sides of both ends of the screw shaft and the casing are in a similar low-pressure environment, and the inner side of the pressurized chamber is close to the inner wall of the pressurized chamber. The high-pressure joint between the wall and the screw shaft is also blocked by the pressure isolation chamber from the outside of the casing. Compared with the external environment, the high-pressure air in the pressurized chamber is relatively less likely to leak from the joint surface with the screw shaft to the pressure isolation chamber with a relatively smaller pressure difference, which is beneficial to improving the sealing performance. Even if a small amount of high-pressure air leaks out, it will circulate into the low-pressure chamber to participate in compression again, reducing energy waste and thus improving the working efficiency of the compression main unit. When two compression main units with the same displacement are arranged in series in the same direction, there will be no one-way leakage problem due to the large pressure difference at the ends, thereby increasing the volume displacement of the compressor and improving the working efficiency of the compressor under the condition of effectively controlling leakage.

[0011] In the above-mentioned air compressor, the side of the inner cylinder cavity close to the input end of the screw shaft is connected to the low-pressure cavity, and the outer peripheral surface sealing sleeve of the screw shaft output end is provided with a disc-shaped labyrinth seal frame, the outer edge of the labyrinth seal frame is sealed with the inner cavity side wall of the inner cylinder cavity, and the labyrinth seal frame includes the supporting baffle, and the pressurized cavity is formed between the side of the labyrinth seal frame close to the input end of the screw shaft and the inner cavity side wall of the inner cylinder cavity, and the pressure isolation cavity is formed between the outer edge of the labyrinth seal frame or the other side of the labyrinth seal frame and the inner cavity side wall of the inner cylinder cavity. The inner cylinder cavity in the existing compression main unit is used to cooperate with the outer peripheral surface of the screw. The side wall of the inner cylinder cavity is cylindrical and separated from the low-pressure cavity. The side of the inner cylinder cavity close to the input end of the screw shaft is connected to the low-pressure cavity. In this way, the inner cylinder cavity structure in the existing casing product can be utilized. By adding a labyrinth sealing frame and opening a through hole on the basis of the original casing, the inner cylinder cavity is divided into a pressurized cavity and a pressure isolation cavity. In this way, it can be achieved by only processing on the basis of the original product without changing the product mold, which greatly saves production costs and achieves the purpose of increasing the volume displacement of the compressor under the condition of effectively controlling leakage.

[0012] In the above-mentioned air compressor, the labyrinth seal frame has a pressure-equalizing groove arranged around the labyrinth seal frame and the screw shaft at the same time, the inner wall of the inner cylinder cavity has a through hole connected to the low-pressure cavity, the pressure-equalizing groove is connected to the through hole, and the pressure-isolating cavity is formed between the inner cavity side wall of the pressure-equalizing groove and the inner cavity side wall of the inner cylinder cavity. By arranging the pressure-equalizing groove arranged around the labyrinth seal frame on the labyrinth seal frame, the pressure-equalizing groove is connected to the low-pressure cavity through the through hole on the inner wall of the inner cylinder cavity, so that the pressure-equalizing groove can achieve pressure close to that of the low-pressure cavity on both the screw shaft and the inner cylinder cavity circumferential surface, ensuring that only low-pressure air is involved even when the casing leaks from the outside, greatly reducing the impact of sealing leakage.

[0013] In the above-mentioned air compressor, the side of the labyrinth seal away from the input end of the screw shaft abuts against the bottom surface of the inner cylinder cavity. By setting the side of the labyrinth seal away from the input end of the screw shaft abutting against the bottom surface of the inner cylinder cavity, the bottom surface of the inner cylinder cavity can provide rigid support for the labyrinth seal to offset the pressure of the high-pressure gas in the screw area, ensuring structural stability without sealing failure due to the movement of the labyrinth seal.

[0014] In the above-mentioned air compressor, several compression hosts are coaxially arranged in series, and two adjacent housings are fixedly connected by flange barrels. In this way, the volume displacement of the compressor is increased under the condition of effectively controlling leakage, and the working efficiency of the compressor is improved. By setting the adjacent housings to be fixedly connected by flange barrels, the relative stability of the housing position and the connection strength are improved, thereby avoiding excessive tangential loads between the screw shafts affecting the normal series operation of multiple compression hosts.

[0015] In the above-mentioned air compressor, the compressor further includes a gas-liquid separator, and the exhaust ports of the plurality of compression hosts are all connected to the gas-liquid separator through an exhaust pipe. The gas-liquid separator can separate air and coolant, and the coolant can be oil or water. By setting the compressor to further include a gas-liquid separator, the exhaust ports of the plurality of compression hosts are all connected to the gas-liquid separator through the exhaust pipe, so that a plurality of compression hosts of the same specification can share the same gas-liquid separator because the compressed air pressure generated is close, which is conducive to cost saving.

[0016] In the above-mentioned air compressor, the compressor further includes a plurality of return pipes, one end of which can be connected to the liquid outlet pipe of the gas-liquid separator, and the other end of which is connected to the inner cavity of the casing. By providing a plurality of return pipes, one end of the return pipe can be connected to the liquid outlet pipe of the gas-liquid separator, and the other end is connected to the inner cavity of the casing, so that the return pipe can circulate the coolant to cool and lubricate the components of the compression host.

[0017] In the above-mentioned air compressor, the compressor further includes a filter, the liquid outlet pipe of the gas-liquid separator is connected to the filter, and one end of the return pipe can be connected to the filter. By setting the filter, the liquid outlet pipe of the gas-liquid separator is connected to the filter, and one end of the return pipe can be connected to the filter, so that the impurity particles in the coolant can be filtered and then refluxed for utilization, reducing the loss of the star wheel and the screw.

[0018] In the above-mentioned air compressor, the compressor further includes a radiator, the radiator can be communicated with the liquid outlet pipe of the gas-liquid separator, and one end of the return pipe can be communicated with the radiator. By arranging the radiator to be communicated with the liquid outlet pipe of the gas-liquid separator, one end of the return pipe can be communicated with the radiator, so that the radiator can reduce the temperature of the reflux coolant and ensure better cooling and lubrication effects.

[0019] In the above-mentioned air compressor, there are a plurality of radiators arranged at intervals, and the positions of the plurality of radiators are directly opposite to the positions of the plurality of compression main units along the vertical direction of the screw shaft. By arranging a plurality of radiators arranged at intervals, the positions of the plurality of radiators are directly opposite to the positions of the plurality of compression main units along the vertical direction of the screw shaft, so that each compression main unit can cool the coolant through an independent radiator and then recycle it, which is conducive to ensuring better cooling and lubrication effects.

[0020] In the above-mentioned air compressor, the top and bottom of each housing inner cavity are connected to a return pipe. By connecting the top and bottom of each housing inner cavity to a return pipe, it is beneficial to cool the meshing points of different star wheels and screws from the upper and lower directions, thereby improving the cooling effect.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] The air compressor is provided with a plurality of compression mainframes with the same displacement arranged coaxially, which is advantageous for using the same motor to drive the plurality of compression mainframes to work synchronously, thereby ensuring that the working states of the two compression mainframes are synchronized and consistent, and the effect of doubling the volumetric displacement can be quickly achieved; at the same time, when a plurality of compression mainframes with the same specification are coaxially arranged in series, the volumetric displacement can be quickly doubled, and the problem of one-way leakage due to the large pressure difference at the two ends of the compression mainframe due to the series arrangement will not occur, thereby improving the volumetric displacement of the compressor under the condition of effectively controlling the leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the three-dimensional structure of the first embodiment.

[0024] Figure 2 It is a schematic cross-sectional structure diagram of the first embodiment.

[0025] Figure 3 yes Figure 2 Enlarged view of part A in .

[0026] Figure 4 It is a schematic diagram of the three-dimensional structure of the compression host unit in the first embodiment.

[0027] Figure 5 It is a schematic cross-sectional view of the local structure of the compression host unit in the first embodiment.

[0028] Figure 6 It is a three-dimensional schematic diagram of the local structure of the compression host unit in the first embodiment.

[0029] Figure 7 It is a three-dimensional schematic diagram of the local structure of the casing in the first embodiment.

[0030] Figure 8 It is a schematic diagram of the three-dimensional structure of the labyrinth sealing frame in the first embodiment.

[0031] Fig. 9 It is a schematic diagram of the three-dimensional structure of the first embodiment from another angle.

[0032] In the figure, 1, compression main unit; 11, housing; 111, air inlet; 112, exhaust port; 12, screw shaft; 13, low-pressure chamber; 14, pressurized chamber; 15, pressure-isolating chamber; 16, inner cylinder chamber; 161, through hole;

[0033] 2. Motor;

[0034] 3. Labyrinth sealing frame; 31. Pressure equalizing groove; 32. Supporting partition;

[0035] 4. Flange cylinder;

[0036] 5. Gas-liquid separator; 51. Liquid outlet pipe;

[0037] 6. Exhaust pipe; 7. Return pipe; 8. Filter; 9. Radiator. DETAILED DESCRIPTION

[0038] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments. Embodiment 1:

[0039] like Figure 1-9As shown, the air compressor includes two compression hosts 1 and a motor 2 for driving the compression hosts 1 to work. The compression host 1 includes a casing 11 and a screw shaft 12 for assembling to form a screw. The outer peripheral surface of the casing 11 has an air inlet 111 and an exhaust port 112. The casing 11 has a low-pressure chamber 13 connected to the air inlet 111 and an inner cylinder chamber 16 arranged along the axial direction of the inner cylinder chamber 12 and capable of matching with the outer peripheral surface of the screw. The inner side wall of the inner cylinder chamber 16 is cylindrical, and one end of the inner cylinder chamber 16 close to the input end of the screw shaft 12 is connected to the low-pressure chamber 13. The circumferential side wall of the inner cylinder chamber 16 has a channel connected to the exhaust port 112, and the circumferential side wall of the inner cylinder chamber 16 also has a through hole 161 connected to the low-pressure chamber 13. The outer circumference of the output end of the screw shaft 12 is sleeved with a support baffle 32, which divides the inner cylinder cavity 16 into a pressurized cavity 14 and a pressure-isolating cavity 15 which is only connected to the through hole 161. Specifically, the outer circumference of the screw shaft 12 is sleeved with a labyrinth sealing frame 3, which includes a support baffle 32. The labyrinth sealing frame 3 is disc-shaped and the outer edge of the labyrinth sealing frame 3 is sealed with the inner side wall of the pressurized cavity 14. The pressurized cavity 14 is formed between the side of the labyrinth sealing frame 3 close to the input end of the screw shaft 12 and the inner side wall of the inner cylinder cavity 16, and the pressure-isolating cavity 15 is formed between the outer edge of the labyrinth sealing frame 3 and the inner side wall of the inner cylinder cavity 16. The displacement of the two compression hosts 1 is the same, and the screw shafts 12 of the two compression hosts 1 are coaxially arranged in series. The compression host 1 is an important working unit of the air compressor. Its casing 11 provides protection and a closed environment for the internal screw shaft 12, star wheel and screw. When the motor 2 drives the screw shaft 12 to rotate, it can drive the screw to rotate and drive the star wheel engaged with the screw to rotate. At this time, a closed volume is formed between the screw groove on the screw, the inner wall of the pressurized chamber 14 and the star wheel. The air entering the low-pressure chamber 13 from the air inlet 111 is sucked into the closed volume and gradually compressed, and finally discharged through the exhaust port 112 to realize the compression operation. By arranging a labyrinth seal frame 3 sleeved on the outer peripheral surface of the screw shaft 12 in the inner cylinder cavity 16, the outer edge of the disc-shaped labyrinth seal frame 3 is sealed with the inner side wall of the pressurizing cavity 14, and the inner cylinder cavity 16 is divided into the pressurizing cavity 14 and the pressure isolating cavity 15, and two compression hosts 1 are arranged coaxially in series. In this way, under the condition of ensuring normal compression work, the air in the low-pressure area can enter the space between the labyrinth seal frame 3 and the bottom surface of the inner cylinder cavity 16 through the through hole 161, so that both ends of the inner cylinder cavity 16 along the screw shaft 12 are low-pressure environments. When two compression hosts 1 of the same specification are arranged in series, the volume displacement can be quickly doubled, and the problem of one-way leakage will not occur due to the difference in high and low pressures at the two opposite ends.Further, the labyrinth seal frame 3 has two annular pressure-equalizing grooves 31 arranged around the labyrinth seal frame 3 and the screw shaft 12. The inner side walls of the pressure-equalizing grooves 31 are fixedly connected by ribs. There are two through holes 161. The two pressure-equalizing grooves 31 are respectively connected to the two through holes 161. A pressure-isolating cavity 15 is formed between the pressure-equalizing grooves 31 and the inner side wall of the inner cylinder cavity 16. The two through holes 161 are located at the lower side of the pressure-isolating cavity 15. Both through holes 161 are strip-shaped and arranged around the inner side wall of the inner cylinder cavity 16. By providing the pressure-equalizing grooves 31 arranged around the labyrinth seal frame 3 on the labyrinth seal frame 3, the pressure-equalizing grooves 31 are connected to the through holes 161. In this way, the pressure-equalizing grooves 31 can achieve pressure close to that of the low-pressure cavity 13 on the circumferential surfaces of the screw shaft 12 and the inner cylinder cavity 16, ensuring that only low-pressure air is involved when leakage occurs with the outside world, greatly reducing the impact of sealing leakage. Preferably, one side of the labyrinth seal frame 3 is arranged toward the motor 2, and the other side of the labyrinth seal frame 3 is against the bottom surface of the inner cylinder cavity 16. By setting one side of the labyrinth seal frame 3 to face the motor 2 and the other side to abut against the bottom surface of the inner end of the inner cylinder cavity 16, the bottom surface of the inner cylinder cavity 16 can provide rigid support for the labyrinth seal frame 3 to offset the pressure of the high-pressure gas in the screw area, ensuring that the structure is stable and will not cause the labyrinth seal frame 3 to fail. The two adjacent casings 11 are fixedly connected by the flange cylinder 4, and the two adjacent screw shafts 12 are connected by a coupling transmission. By setting the two adjacent casings 11 to be fixedly connected by the flange cylinder 4, it is beneficial to the relative stability of the position of the casing 11 and improve the connection strength, thereby avoiding excessive tangential loads between the screw shafts 12 affecting the normal series operation of the two compression hosts 1.

[0040] like Figure 1-4 , Fig. 9As shown, the compressor also includes a gas-liquid separator 5, and the exhaust ports 112 of several compressor main units 1 are all connected to the gas-liquid separator 5 through the exhaust pipe 6. The gas-liquid separator 5 can separate air and coolant, and the coolant can be oil or water. By setting the compressor to also include a gas-liquid separator 5, the exhaust ports 112 of several compressor main units 1 are all connected to the gas-liquid separator 5 through the exhaust pipe 6, so that two compressor main units 1 of the same specification can share the same gas-liquid separator 5 due to the similar compressed air pressure generated, which is conducive to cost saving. The compressor also includes four return pipes 7, one end of the return pipe 7 can be connected to the liquid outlet pipe 51 of the gas-liquid separator 5, and the other end of the return pipe 7 is connected to the inner cavity of the casing 11. By setting a plurality of return pipes 7, one end of the return pipe 7 can be connected to the liquid outlet pipe 51 of the gas-liquid separator 5, and the other end is connected to the inner cavity of the casing 11, so that the return pipe 7 can circulate the coolant to cool and lubricate the components of the compressor main unit 1. The compressor also includes a filter 8, the liquid outlet pipe 51 of the gas-liquid separator 5 is connected to the filter 8, and one end of the return pipe 7 can be connected to the filter 8. By setting the filter 8, the liquid outlet pipe 51 of the gas-liquid separator 5 is connected to the filter 8, and one end of the return pipe 7 can be connected to the filter 8, so that the impurity particles in the coolant can be filtered and then refluxed, reducing the loss of the star wheel and the screw. The compressor also includes a radiator 9, which can be connected to the liquid outlet pipe 51 of the gas-liquid separator 5, and one end of the return pipe 7 can be connected to the radiator 9. By setting the radiator 9 to be connected to the liquid outlet pipe 51 of the gas-liquid separator 5, one end of the return pipe 7 can be connected to the radiator 9, so that the radiator 9 can reduce the temperature of the reflux coolant and ensure better cooling and lubrication effects. There are two radiators 9 and they are arranged at intervals. The positions of the two radiators 9 are directly opposite to the positions of the two compression hosts 1 along the vertical direction of the screw shaft 12. By providing two radiators 9 and arranging them at intervals, the positions of the two radiators 9 are directly opposite to the positions of the two compression mainframes 1 along the vertical direction of the screw shaft 12, so that each compression mainframe 1 can cool the coolant through an independent radiator 9 and then recycle it, which is conducive to ensuring better cooling and lubrication effects. Preferably, the top and bottom of the inner cavity of each housing 11 are connected to a return pipe 7. By connecting the top and bottom of the inner cavity of each housing 11 to a return pipe 7, it is conducive to cooling the meshing points of different star wheels and screws from the upper and lower directions, thereby improving the cooling effect. Embodiment 2:

[0041] This embodiment is basically the same as the first embodiment, except that: the upper end side wall position of the through hole 161 near the motor 2 is lower than the upper end side wall position of the other through hole 161; when the compressor is working, there will be lubricating liquid in the casing 11, and the lubricating liquid can be water or lubricating oil. The lubricating liquid can cover the two through holes 161 at the lower position. Since the through hole 161 near the motor 2 is at a lower position, the air pressure in the corresponding pressure isolation cavity 15 formed by the pressure of the lubricating liquid is greater than the air pressure of the other pressure isolation cavity 15, thereby forming an axial step along the screw shaft. With the sealing protection of the type, the pressure difference between the pressure isolating chamber 15 close to the pressurized chamber 14 and the pressurized chamber 14 is smaller, and the pressure difference between the other pressure isolating chamber 15 and the outside and the pressure isolating chamber 15 close to the pressurized chamber 14 is also smaller. When part of the gas in the pressurized chamber 14 leaks, it will first enter the pressure isolating chamber 15 close to the pressurized chamber 14 and be partially discharged from the through hole 161, so that the pressure in the pressure isolating chamber 15 still maintains a slightly higher pressure, effectively alleviating the leakage problem caused by the large pressure difference, achieving a more excellent protective sealing effect, and meeting the sealing requirements of multiple host machines in series to improve the working efficiency of the compressor.

[0042] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. An air compressor, comprising a compression main unit (1) and a motor (2) for driving the compression main unit (1) to work, the compression main unit comprising a housing (11) and a screw shaft (12), characterized in that: The compressor main unit (1) has a plurality of them, the screw shafts (12) of the plurality of compressor main units (1) are coaxially arranged and can rotate synchronously, and the exhaust ports (112) of the plurality of compressor main units (1) are all connected to the same gas-liquid separator (5); the casing (11) has an inner cylinder cavity (16) for accommodating the screw shaft (12) and a low-pressure cavity (13) for accommodating a star wheel, the inner cylinder cavity (16) is provided with a support baffle (32), and the output end of the screw shaft (12) is rotatably connected to the support baffle (3 2), the support partition (32) can separate the inner cylinder cavity (16) into a pressurized cavity (14) for compressed air and a pressure-isolating cavity (15) that is only connected to the low-pressure cavity (13), the inner cylinder cavity (16) is connected to the low-pressure cavity (13) on one side close to the input end of the screw shaft (12), and the outer peripheral surface sealing sleeve of the output end of the screw shaft (12) is provided with a disc-shaped labyrinth seal frame (3), the outer edge of the labyrinth seal frame (3) is sealed with the inner cavity side wall of the inner cylinder cavity (16), and the labyrinth seal frame (3) is The invention comprises a supporting baffle (32), a pressurizing chamber (14) is formed between a side of the labyrinth sealing frame (3) close to the input end of the screw shaft (12) and the inner cavity side wall of the inner cylinder cavity (16), a pressure isolating chamber (15) is formed between the outer edge of the labyrinth sealing frame (3) and the inner cavity side wall of the inner cylinder cavity (16), the labyrinth sealing frame (3) has two pressure equalizing grooves (31) arranged around the circumference of the labyrinth sealing frame (3) and the circumference of the screw shaft (12), and the inner side wall of the inner cylinder cavity (16) has two pressure equalizing grooves (31) arranged around the circumference of the labyrinth sealing frame (3) and the circumference of the screw shaft (12), and the inner side wall of the inner cylinder cavity (16) has two pressure equalizing grooves (31) arranged around the low-pressure chamber (15) and the inner side wall of the inner cylinder cavity (16). (13) connected to the through hole (161), the two pressure equalizing grooves (31) are respectively connected to the two through holes (161), the pressure isolation cavity (15) is formed between the inner cavity side wall of the pressure equalizing groove (31) and the inner cavity side wall of the inner cylinder cavity (16), the two through holes (161) are located at the lower side of the pressure isolation cavity (15), the two through holes (161) are both strip-shaped and are arranged circumferentially around the inner wall of the inner cylinder cavity (16), and the upper end side wall position of the through hole (161) close to the motor (2) is lower than the upper end side wall position of the other through hole (161).

2. The air compressor according to claim 1, characterized in that: The motor (2) is coaxially arranged in series with a plurality of the compression main machines (1), and two adjacent compression main machines (1) are fixedly connected via a flange cylinder (4).

3. The air compressor according to claim 1 or 2, characterized in that: The exhaust ports (112) of the plurality of compressor main units (1) are all connected to the gas-liquid separator (5) via an exhaust pipe (6). The compressor further comprises a plurality of return pipes (7), one end of the return pipe (7) being able to be connected to the liquid outlet pipe (51) of the gas-liquid separator (5), and the other end of the return pipe (7) being connected to the inner cavity of the compressor main unit (1).

4. The air compressor according to claim 3, characterized in that: The compressor further comprises a filter (8), the liquid outlet pipe (51) of the gas-liquid separator (5) is connected to the filter (8), and one end of the return pipe (7) can be connected to the filter (8).

5. The air compressor according to claim 3, characterized in that: The compressor further comprises a radiator (9), wherein the radiator (9) can be in communication with a liquid outlet pipe (51) of the gas-liquid separator (5), and one end of the return pipe (7) can be in communication with the radiator (9).

6. The air compressor according to claim 1 or 2, characterized in that: The side of the labyrinth seal frame (3) away from the input end of the screw shaft (12) is in limited contact with the bottom surface of the inner cylinder cavity (16).

7. The air compressor according to claim 3, characterized in that: The top and bottom of the inner cavity of each compression main unit (1) are respectively connected to a return pipe (7).

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