CN218934722U - Double-stage dry oil-free screw compressor - Google Patents

Abstract

The utility model relates to a two-stage dry oil-free screw compressor, and belongs to the technical field of compressors. The existing cooling system has poor cooling effect. The utility model comprises a low-voltage level motor, a low-voltage level gear box, a high-voltage level motor and a high-voltage level gear box; the method is characterized in that: the low-pressure gear box is characterized by further comprising an oil tank, an overflow valve and an oil filter, wherein the bottom of the low-pressure gear box and the bottom of the high-pressure gear box are both fixed at the top of the oil tank, the overflow valve is arranged on the low-pressure gear box, and the oil filter is arranged on the low-pressure gear box; the two ends of the first oil delivery pipe are respectively connected to the low-voltage level motor and the high-voltage level motor, the two ends of the second oil delivery pipe are respectively connected to the high-voltage level motor and the high-voltage level gear box, the internal oil duct of the high-voltage level gear box is communicated with the cooling liquid cavity in the high-voltage level shell, and the two ends of the third oil delivery pipe are respectively connected to the high-voltage level shell and the low-voltage level shell. The utility model has reasonable structural design and good cooling effect.

Description

Double-stage dry oil-free screw compressor

Technical Field

The utility model relates to a two-stage dry oil-free screw compressor, and belongs to the technical field of compressors.

Background

A two-stage dry oil-free screw compressor is a compressor having two pairs of screws, which compress gas twice. When the dry oil-free screw compressor is in operation, no liquid is sprayed in the compression cavity, and the compressed gas is not polluted, so that the dry oil-free screw compressor is widely applied to the medical and food industries. Because the compression cavity of the dry oil-free screw compressor is not sprayed with liquid, after the compressor runs for a long time, the compressor shell and the male and female rotors can generate heat, so that the overall performance of the compressor is affected, the compressor needs to be cooled, the cooling effect of the existing cooling system is poor, and the compressor shell and the male and female rotors cannot be cooled effectively.

Disclosure of Invention

The utility model aims to overcome the defects in the prior art and provide the double-stage dry oil-free screw compressor which is reasonable in structural design and good in cooling effect.

The utility model solves the problems by adopting the following technical scheme: the double-stage dry oil-free screw compressor comprises a low-pressure stage motor, a low-pressure stage gear box, a low-pressure stage shell, a low-pressure stage exhaust end and a low-pressure stage rear cover plate which are sequentially connected, a high-pressure stage motor, a high-pressure stage gear box, a high-pressure stage shell, a high-pressure stage exhaust end and a high-pressure stage rear cover plate which are sequentially connected, a low-pressure stage female rotor and a low-pressure stage male rotor which are meshed with each other and are arranged in the low-pressure stage shell, a low-pressure stage synchronous gear connected at the end parts of the low-pressure stage female rotor and the low-pressure stage male rotor, a high-pressure stage female rotor and a high-pressure stage male rotor which are meshed with each other and are arranged in the high-pressure stage shell, and a high-pressure stage synchronous gear connected at the end parts of the high-pressure stage female rotor and the high-pressure stage male rotor; the low-pressure stage shell is provided with an air inlet, the high-pressure stage shell is provided with an air outlet, and the high-pressure stage shell is communicated with the low-pressure stage shell; the structure is characterized in that: the low-pressure-stage oil tank comprises a low-pressure-stage gear box body, and is characterized by further comprising an oil tank, an overflow valve, an oil filter, a first oil return pipe, a second oil return pipe, a third oil return pipe, a fourth oil return pipe, a fifth oil return pipe, a first oil delivery pipe, a second oil delivery pipe, a third oil delivery pipe, a fourth oil delivery pipe, a fifth oil delivery pipe and a sixth oil delivery pipe, wherein the bottom of the low-pressure-stage gear box body and the bottom of the high-pressure-stage gear box body are both fixed at the top of the oil tank, the overflow valve is arranged on a low-pressure-stage shell body, and the oil filter is arranged on the low-pressure-stage gear box body; the two ends of the first oil delivery pipe are respectively connected to the low-pressure motor and the high-pressure motor, the two ends of the second oil delivery pipe are respectively connected to the high-pressure motor and the high-pressure gear box, an internal oil duct of the high-pressure gear box is communicated with a cooling liquid cavity in the high-pressure shell, the two ends of the third oil delivery pipe are respectively connected to the high-pressure shell and the low-pressure shell, the cooling liquid cavity in the low-pressure shell is communicated with an overflow valve, the two ends of the fourth oil delivery pipe are respectively connected to the overflow valve and an oil filter, the oil filter is communicated with an internal oil duct of the low-pressure gear box, the two ends of the fifth oil delivery pipe are respectively connected to the low-pressure gear box and the high-pressure gear box, and the two ends of the sixth oil delivery pipe are respectively connected to bearing cavities at the ends of the high-pressure gear box and the high-pressure motor; the overflow valve is communicated with the oil tank through a first oil return pipe, the low-pressure-stage exhaust end is communicated with the oil tank through a second oil return pipe, the high-pressure-stage exhaust end is communicated with the oil tank through a third oil return pipe, the bearing cavity of the high-pressure-stage motor is communicated with the high-pressure-stage gear box through a fourth oil return pipe, the high-pressure-stage gear box is communicated with the oil tank through a high-pressure oil return hole arranged at the bottom, the bearing cavity of the low-pressure-stage motor is communicated with the low-pressure-stage gear box through a fifth oil return pipe, and the low-pressure-stage gear box is communicated with the oil tank through a low-pressure oil return hole arranged at the bottom.

Preferably, the present utility model further includes a low-voltage motor auxiliary support fixed between the low-voltage stage motor and the oil tank, and a high-voltage motor auxiliary support fixed between the high-voltage stage motor and the oil tank.

Preferably, a low-voltage-stage speed-increasing driving gear and a low-voltage-stage speed-increasing driven gear which are meshed with each other are arranged in the low-voltage-stage gear box, the low-voltage-stage speed-increasing driving gear is connected with a motor output shaft in a low-voltage-stage motor, and the low-voltage-stage speed-increasing driven gear is connected with a low-voltage-stage male rotor; the high-voltage-stage gear box is internally provided with a high-voltage-stage speed-increasing driving gear and a high-voltage-stage speed-increasing driven gear which are meshed with each other, the high-voltage-stage speed-increasing driving gear is connected with a motor output shaft in a high-voltage-stage motor, and the high-voltage-stage speed-increasing driven gear is connected with a high-voltage-stage male rotor.

Preferably, the low-voltage motor is provided with an oil inlet.

Preferably, the oil tank is of a whole casting structure, and the cover plate of the oil tank is arranged at the bottom of the oil tank.

Preferably, the bottom of the low-pressure stage gear box is fixed on the top of the oil tank through bolts, and the bottom of the high-pressure stage gear box is fixed on the top of the oil tank through bolts.

Preferably, the two-stage dry oil-free screw compressor has only one oil inlet hole.

Preferably, the internal oil duct of the high-voltage stage gear box is divided into a plurality of branches, and the branches are respectively communicated with a gear in the high-voltage stage gear box, bearing cavities at two ends of the high-voltage stage female rotor and the high-voltage stage male rotor and bearing cavities of the high-voltage stage motor. The internal oil duct of the low-pressure stage gear box is the same as the internal oil duct of the high-pressure stage gear box, the internal oil duct of the low-pressure stage gear box is divided into a plurality of branch flows, and the plurality of branch flows respectively flow to the gear in the low-pressure stage gear box, the bearing cavities at the two ends of the low-pressure stage female rotor and the low-pressure stage male rotor and the bearing cavity of the low-pressure stage motor.

A cooling method of a two-stage dry oil-free screw compressor is characterized in that: the cooling method comprises the following steps: before starting up, adding a proper amount of oil into the oil tank; the oil in the oil tank is pumped out by an external oil pump, flows through the external oil pump and then enters an oil inlet hole of a low-pressure motor, the oil enters the motor shell of the low-pressure motor to cool the low-pressure motor, then enters the motor shell of a high-pressure motor through a first oil delivery pipe to cool the high-pressure motor, enters an internal oil duct of a high-pressure gear box through a second oil delivery pipe, is communicated with a cooling liquid cavity of the high-pressure shell, enters the high-pressure shell through the internal oil duct to cool the high-pressure shell, and a high-pressure female rotor and a high-pressure male rotor arranged in the high-pressure shell, then exits from an oil outlet hole of the high-pressure shell, enters a cooling liquid cavity of the low-pressure shell through a third oil delivery pipe to cool the low-pressure shell, and a low-pressure female rotor and a low-pressure male rotor arranged in the low-pressure shell, the oil after the oil filtration enters an internal oil passage of the low-pressure stage gear box, the internal oil passage of the low-pressure stage gear box is identical with the internal oil passage of the high-pressure stage gear box, the internal oil passage of the low-pressure stage gear box is divided into a plurality of branch flows, the branch flows respectively flow to a gear in the low-pressure stage gear box, bearing cavities at two ends of a low-pressure stage female rotor and a low-pressure stage male rotor and bearing cavities of a low-pressure stage motor, corresponding gears and bearings are lubricated and cooled, the oil comes out from the internal oil passage of the low-pressure stage gear box, enters the internal oil passage of the high-pressure stage gear box through a fifth oil conveying pipe, the internal oil passage of the high-pressure stage gear box is divided into a plurality of branch flows, and the branch flows respectively flow to the gears in the high-pressure stage gear box, bearing cavities at two ends of the high-voltage-stage female rotor and the high-voltage-stage male rotor and bearing cavities of the high-voltage-stage motor, and lubricate and cool corresponding gears and bearings; the oil enters a bearing cavity at the outer end of the high-voltage motor through a sixth oil delivery pipe to lubricate a bearing in the high-voltage motor; the pressure of oil inlet is regulated through an overflow valve, redundant oil returns to the oil tank through a first oil return pipe, oil flowing to the low-pressure-stage exhaust end returns to the oil tank through a second oil return pipe, and oil flowing to the high-pressure-stage exhaust end returns to the oil tank through a third oil return pipe; oil flowing into a bearing cavity of the high-voltage level motor at the far end of the high-voltage level gear box returns to the high-voltage level gear box through a fourth oil return pipe, and oil in the high-voltage level gear box returns to the oil tank through a high-voltage oil return hole at the bottom; oil flowing into the bearing cavity of the low-voltage stage motor at the far end of the low-voltage stage gear box returns to the low-voltage stage gear box through a fifth oil return pipe, and oil in the low-voltage stage gear box returns to the oil tank through a low-voltage oil return hole at the bottom.

Preferably, the oil flowing to the bearing near one end of the low-pressure stage gearbox in the low-pressure stage shell body flows to the low-pressure stage speed-increasing driving gear, the low-pressure stage speed-increasing driven gear and directly returns to the low-pressure stage gearbox; oil flowing to the bearing near one end of the high-pressure stage gearbox in the high-pressure stage shell body, which is arranged on the high-pressure stage speed-increasing driving gear, the high-pressure stage speed-increasing driven gear and the high-pressure stage shell body, directly returns to the high-pressure stage gearbox.

Compared with the prior art, the utility model has the following advantages and effects: through the cooperation between several oil return pipes, oil delivery pipe and the inside oil duct, can carry out comprehensive cooling and lubrication to the dry-type oilless screw compressor of doublestage, after the long-time operation of compressor, can effectively reduce the condition of generating heat of compressor casing and negative and positive rotor, cool off casing and rotor with lubricating oil. The two motor-driven dry oil-free screw compressors can adjust the rotating speed of the secondary male rotor and the interstage pressure at any time, so that the performance of the two motor-driven dry oil-free screw compressors is optimal.

The bottom of the main machine is the oil tank, the oil tank comprises supporting feet of the whole main machine, the whole casting is made, the whole rigidity is guaranteed, and the oil tank cover plate is arranged at the bottom of the oil tank, so that the cleaning is convenient. The low-voltage level shell is hung on the low-voltage level gear box, the low-voltage level motor is arranged on the other side of the low-voltage gear box, the low-voltage level gear box is connected with the oil tank by using bolts in a fastening way, an auxiliary support is arranged at the front end of the motor, vibration of the motor is reduced, and the connection rigidity of the whole host and the oil tank is enhanced.

Drawings

In order to more clearly illustrate the embodiments of the utility model and/or the technical solutions of the prior art, the drawings that are required in the description of the embodiments and/or the prior art will be briefly described below, it being obvious that the drawings in the description below are only some embodiments of the utility model and that other drawings may be obtained from these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic perspective view of a dual stage dry oil-free screw compressor in accordance with an embodiment of the present utility model.

Fig. 2 is a schematic perspective view of another view of a dual stage dry oil-free screw compressor in accordance with an embodiment of the present utility model.

Fig. 3 is a schematic diagram of a front view of a dual stage dry oil-free screw compressor in accordance with an embodiment of the present utility model.

Fig. 4 is a schematic left-view structure of a dual-stage dry oil-free screw compressor according to an embodiment of the present utility model.

Fig. 5 is a schematic diagram of a right-side view of a dual-stage dry oil-free screw compressor in accordance with an embodiment of the present utility model.

Fig. 6 is a schematic rear view of a dual stage dry oil-free screw compressor in accordance with an embodiment of the present utility model.

Fig. 7 is a schematic bottom view of a dual stage dry oil-free screw compressor in accordance with an embodiment of the present utility model.

Fig. 8 is a schematic top view of a dual stage dry oil free screw compressor in accordance with an embodiment of the present utility model.

Fig. 9 is a schematic cross-sectional view of A-A of fig. 8.

In the figure: 1-a low pressure stage housing; 2-a high pressure stage housing; 3-an oil tank; 4-overflow valve; 5-oil filtering; 61-low voltage stage motor; 611-an oil inlet hole; 62-low-pressure stage gearbox; 621-a low-pressure stage speed-increasing driving gear; 622-low-pressure stage speed-increasing driven gear; 63—a low pressure stage exhaust; 64-low pressure stage back cover plate; 65-a piezoelectric auxiliary support; 66-low pressure stage female rotor; 67-low pressure stage male rotor; 68-low-pressure stage synchronizing gear; 71-a high-voltage motor; 72-high-pressure stage gearbox; 73-high pressure stage exhaust end; 74-high pressure stage back cover plate; 75-high voltage motor auxiliary support; 81-a first oil return pipe; 82-a second oil return pipe; 83-a third oil return pipe; 84-fourth oil return pipe; 85-fifth oil return pipe; 91-a first oil delivery pipe; 92-second oil delivery pipe; 93-third oil delivery pipe; 94-fourth oil delivery pipe; 95-fifth oil delivery pipe; 96-sixth oil delivery pipe.

Detailed Description

The present utility model will be described in further detail by way of examples with reference to the accompanying drawings, which are illustrative of the present utility model and not limited to the following examples.

Examples

Referring to fig. 1 to 9, the two-stage dry oil-free screw compressor in the present embodiment includes a low-pressure stage housing 1, a high-pressure stage housing 2, an oil tank 3, an overflow valve 4, an oil filter 5, a low-pressure stage motor 61, a low-pressure stage gear box 62, a low-pressure stage discharge end 63, a low-pressure stage back cover plate 64, a low-pressure motor auxiliary support 65, a low-pressure stage female rotor 66, a low-pressure stage male rotor 67, a low-pressure stage synchronous gear 68, a high-pressure stage motor 71, a high-pressure stage gear box 72, a high-pressure stage discharge end 73, a high-pressure stage back cover plate 74, a high-pressure motor auxiliary support 75, a high-pressure stage female rotor, a high-pressure stage male rotor, a high-pressure stage synchronous gear, an oil return pipe 81, an oil return pipe 82, an oil return pipe 83, an oil return pipe 84, an oil return pipe 85, an oil return pipe 91, an oil return pipe 92, an oil return pipe 93, an oil return pipe 94, an oil return pipe 95 and an oil pipe 96. The low-voltage motor 61 is provided with an oil inlet hole 611, so that the connection is convenient; the oil tank 3 is of a whole casting structure, the whole rigidity is ensured, and the cover plate of the oil tank 3 is arranged at the bottom of the oil tank 3.

The low-pressure stage motor 61, the low-pressure stage gear box 62, the low-pressure stage housing 1, the low-pressure stage exhaust end 63 and the low-pressure stage rear cover plate 64 in this embodiment are sequentially connected, the high-pressure stage motor 71, the high-pressure stage gear box 72, the high-pressure stage housing 2, the high-pressure stage exhaust end 73 and the high-pressure stage rear cover plate 74 are sequentially connected, the low-pressure stage female rotor 66 and the low-pressure stage male rotor 67 are meshed with each other and installed in the low-pressure stage housing 1, the low-pressure stage synchronous gear 68 is connected to the ends of the low-pressure stage female rotor 66 and the low-pressure stage male rotor 67, the high-pressure stage female rotor and the high-pressure stage male rotor are meshed with each other and installed in the high-pressure stage housing 2, and the high-pressure stage synchronous gear is connected to the ends of the high-pressure stage female rotor and the high-pressure stage male rotor; the low pressure stage housing 1 is provided with an air inlet, the high pressure stage housing 2 is provided with an air outlet, and the high pressure stage housing 2 and the low pressure stage housing 1 communicate.

The bottom of the low-pressure stage gearbox 62 and the bottom of the high-pressure stage gearbox 72 in this embodiment are both fixed to the top of the oil tank 3, typically by bolts. The overflow valve 4 is arranged on the low-pressure stage shell 1, and the oil filter 5 is arranged on the low-pressure stage gearbox 62; the relief valve 4 functions as: the pressure of the oil is regulated by the relief valve 4, and the excess oil is returned to the tank through the first oil return pipe 81.

The auxiliary support 65 for the low-voltage motor in this embodiment is fixed between the low-voltage motor 61 and the oil tank 3, and the auxiliary support 75 for the high-voltage motor is fixed between the high-voltage motor 71 and the oil tank 3, so that vibration of the motor is reduced, and the connection rigidity between the whole host and the oil tank 3 is enhanced.

In this embodiment, two ends of the first oil delivery pipe 91 are respectively connected to the low-pressure motor 61 and the high-pressure motor 71, two ends of the second oil delivery pipe 92 are respectively connected to the high-pressure motor 71 and the high-pressure gear box 72, an internal oil duct of the high-pressure gear box 72 is communicated with a cooling liquid cavity in the high-pressure shell 2, two ends of the third oil delivery pipe 93 are respectively connected to the high-pressure shell 2 and the low-pressure shell 1, a cooling liquid cavity in the low-pressure shell 1 is communicated with the overflow valve 4, two ends of the fourth oil delivery pipe 94 are respectively connected to the overflow valve 4 and the oil filter 5, two ends of the fifth oil delivery pipe 95 are respectively connected to the low-pressure gear box 62 and the high-pressure gear box 72, and two ends of the sixth oil delivery pipe 96 are respectively connected to bearing cavities at the ends of the high-pressure gear box 72 and the high-pressure motor 71. The internal oil passage of the high-pressure stage gear box 72 is divided into a plurality of branches, and the plurality of branches are respectively communicated with the gears in the high-pressure stage gear box 72, the bearing cavities at the two ends of the high-pressure stage female rotor and the high-pressure stage male rotor, and the bearing cavities of the high-pressure stage motor 71.

The overflow valve 4 in this embodiment is communicated with the oil tank 3 through a first oil return pipe 81, the low-pressure stage exhaust end 63 is communicated with the oil tank 3 through a second oil return pipe 82, the high-pressure stage exhaust end 73 is communicated with the oil tank 3 through a third oil return pipe 83, the bearing cavity of the high-pressure stage motor 71 is communicated with the high-pressure stage gear box 72 through a fourth oil return pipe 84, the high-pressure stage gear box 72 is communicated with the oil tank 3 through a high-pressure oil return hole arranged at the bottom, the bearing cavity of the low-pressure stage motor 61 is communicated with the low-pressure stage gear box 62 through a fifth oil return pipe 85, and the low-pressure stage gear box 62 is communicated with the oil tank 3 through a low-pressure oil return hole arranged at the bottom.

The low-voltage stage gearbox 62 of the embodiment is provided with a low-voltage stage speed-increasing driving gear 621 and a low-voltage stage speed-increasing driven gear 622 which are meshed with each other, the low-voltage stage speed-increasing driving gear 621 is connected with a motor output shaft in the low-voltage stage motor 61, and the low-voltage stage speed-increasing driven gear 622 is connected with the low-voltage stage male rotor 67; the high-voltage stage gear box 72 is provided with a high-voltage stage speed-increasing driving gear and a high-voltage stage speed-increasing driven gear which are meshed with each other, the high-voltage stage speed-increasing driving gear is connected with a motor output shaft in the high-voltage stage motor 71, and the high-voltage stage speed-increasing driven gear is connected with a high-voltage stage male rotor.

The main steps of the cooling method of the two-stage dry oil-free screw compressor in the embodiment are as follows: after entering the oil inlet hole 611, the oil cools the motor, then cools the shell, and then enters the host lubricating oil system after passing through the overflow valve 4 and the oil filter 5. The specific flow direction is as follows.

Before starting up, adding a proper amount of oil into the oil tank 3; the oil pump is externally connected, oil in the oil tank 3 is pumped out, the oil flows through the external oil pump and then enters the oil inlet hole 611 of the low-pressure motor 61, the oil enters the motor housing of the low-pressure motor 61 after entering the oil inlet hole 611, the low-pressure motor 61 is cooled, then enters the motor housing of the high-pressure motor 71 through the first oil conveying pipe 91, the high-pressure motor 71 is cooled, the oil enters the internal oil duct of the high-pressure gear box 72 through the second oil conveying pipe 92, the internal oil duct is communicated with the cooling liquid cavity of the high-pressure housing 2, the oil enters the high-pressure housing 2 through the internal oil duct, the high-pressure housing 2, the high-pressure female rotor and the high-pressure male rotor which are arranged in the high-pressure housing 2 are cooled, then exits from the oil outlet hole of the high-pressure housing 2, enters the cooling liquid cavity of the low-pressure housing 1 through the third oil conveying pipe 93, the low-pressure female rotor 66 and the low-pressure male rotor 67 which are arranged in the low-pressure housing 1 are cooled, and then the oil overflows through the cooling liquid outlet 4 of the low-pressure housing 1.

The oil flows to the oil filter 5 through the fourth oil pipe 94, the oil filtered by the oil filter 5 enters an internal oil duct of the low-pressure stage gearbox 62, the internal oil duct of the low-pressure stage gearbox 62 is identical to the internal oil duct of the high-pressure stage gearbox 72, the internal oil duct of the low-pressure stage gearbox 62 is divided into a plurality of branches, the branches respectively flow to the gears in the low-pressure stage gearbox 62, the bearing cavities at the two ends of the low-pressure stage female rotor 66 and the low-pressure stage male rotor 67 and the bearing cavities of the low-pressure stage motor 61, lubricate and cool the corresponding gears and bearings, and after coming out from the internal oil duct of the low-pressure stage gearbox 62, the oil enters the internal oil duct of the high-pressure stage gearbox 72 through the fifth oil pipe 95, the internal oil duct of the high-pressure stage gearbox 72 is divided into a plurality of branches, and the branches respectively flow to the gears in the high-pressure stage gearbox 72, the bearing cavities at the two ends of the high-pressure stage female rotor and the high-pressure stage male rotor and the bearing cavities of the high-pressure stage motor 71, lubricate and cool the corresponding gears and bearings; the oil enters a bearing cavity at the outer end of the high-voltage motor 71 through a sixth oil delivery pipe 96 to lubricate the bearing inside the high-voltage motor; the pressure of the oil inlet is regulated through the overflow valve 4, the redundant oil returns to the oil tank 3 through a first oil return pipe 81, the oil flowing to the low-pressure-stage exhaust end 63 returns to the oil tank 3 through a second oil return pipe 82, and the oil flowing to the high-pressure-stage exhaust end 73 returns to the oil tank 3 through a third oil return pipe 83; oil flowing to the low-pressure stage speed-increasing driving gear 621, the low-pressure stage speed-increasing driven gear 622, and the bearing near one end of the low-pressure stage gearbox 62 in the low-pressure stage housing 1 is directly returned to the low-pressure stage gearbox 62; oil flowing to the high-pressure stage speed-increasing driving gear, the high-pressure stage speed-increasing driven gear and the bearing near one end of the high-pressure stage gearbox 72 in the high-pressure stage housing 2 is directly returned to the high-pressure stage gearbox 72.

Oil flowing into the bearing chamber of the high-pressure stage motor 71 at the far end from the high-pressure stage gear box 72 returns to the high-pressure stage gear box 72 through the fourth oil return pipe 84, and oil in the high-pressure stage gear box 72 returns to the oil tank 3 through the high-pressure oil return hole at the bottom; oil flowing into the bearing chamber of the low-pressure stage motor 61 at the far end from the low-pressure stage gear box 62 returns to the low-pressure stage gear box 62 through the No. five oil return pipe 85, and oil in the low-pressure stage gear box 62 returns to the oil tank 3 through the low-pressure oil return hole at the bottom.

In addition, it should be noted that the specific embodiments described in the present specification may vary from part to part, from name to name, etc., and the above description in the present specification is merely illustrative of the structure of the present utility model. All equivalent or simple changes of the structure, characteristics and principle according to the inventive concept are included in the protection scope of the present patent. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions in a similar manner without departing from the scope of the utility model as defined in the accompanying claims.

Claims (7)

1. The double-stage dry oil-free screw compressor comprises a low-pressure stage motor (61), a low-pressure stage gearbox (62), a low-pressure stage shell (1) and a low-pressure stage exhaust end (63) which are sequentially connected, a high-pressure stage motor (71), a high-pressure stage gearbox (72), a high-pressure stage shell (2) and a high-pressure stage exhaust end (73) which are sequentially connected, a low-pressure stage female rotor (66) and a low-pressure stage male rotor (67) which are meshed with each other and are installed in the low-pressure stage shell (1), and a high-pressure stage female rotor and a high-pressure stage male rotor which are meshed with each other and are installed in the high-pressure stage shell (2); the low-pressure stage shell (1) is provided with an air inlet, the high-pressure stage shell (2) is provided with an air outlet, and the high-pressure stage shell (2) is communicated with the low-pressure stage shell (1); the method is characterized in that: the oil filter device comprises an oil tank (3), an overflow valve (4), an oil filter (5), a first oil return pipe (81), a second oil return pipe (82), a third oil return pipe (83), a fourth oil return pipe (84), a fifth oil return pipe (85), a first oil delivery pipe (91), a second oil delivery pipe (92), a third oil delivery pipe (93), a fourth oil delivery pipe (94), a fifth oil delivery pipe (95) and a sixth oil delivery pipe (96), wherein the bottom of a low-pressure gear box (62) and the bottom of a high-pressure gear box (72) are both fixed at the top of the oil tank (3), the overflow valve (4) is arranged on a low-pressure gear box (62), and the oil filter (5) is arranged on the low-pressure gear box (1); the two ends of the first oil delivery pipe (91) are respectively connected to the low-pressure level motor (61) and the high-pressure level motor (71), the two ends of the second oil delivery pipe (92) are respectively connected to the high-pressure level motor (71) and the high-pressure level gear box (72), an internal oil duct of the high-pressure level gear box (72) is communicated with a cooling liquid cavity in the high-pressure level shell (2), the two ends of the third oil delivery pipe (93) are respectively connected to the high-pressure level shell (2) and the low-pressure level shell (1), a cooling liquid cavity in the low-pressure level shell (1) is communicated with an overflow valve (4), the two ends of the fourth oil delivery pipe (94) are respectively connected to the overflow valve (4) and an oil filter (5), the oil filter (5) is communicated with the inside of the low-pressure level gear box (62), the two ends of the fifth oil delivery pipe (95) are respectively connected to the low-pressure level gear box (62) and the high-pressure level gear box (72), and the two ends of the sixth oil delivery pipe (96) are respectively connected to the high-pressure level gear box (72); the overflow valve (4) is communicated with the oil tank (3) through a first oil return pipe (81), the low-pressure-stage exhaust end (63) is communicated with the oil tank (3) through a second oil return pipe (82), the high-pressure-stage exhaust end (73) is communicated with the oil tank (3) through a third oil return pipe (83), a bearing cavity of the high-pressure-stage motor (71) is communicated with the high-pressure-stage gearbox (72) through a fourth oil return pipe (84), the high-pressure-stage gearbox (72) is communicated with the oil tank (3) through a high-pressure oil return hole arranged at the bottom, a bearing cavity of the low-pressure-stage motor (61) is communicated with the low-pressure-stage gearbox (62) through a fifth oil return pipe (85), and the low-pressure-stage gearbox (62) is communicated with the oil tank (3) through a low-pressure oil return hole arranged at the bottom.

2. The dual stage dry oil free screw compressor of claim 1 wherein: the motor control device further comprises a low-voltage motor auxiliary support (65) and a high-voltage motor auxiliary support (75), wherein the low-voltage motor auxiliary support (65) is fixed between the low-voltage motor (61) and the oil tank (3), and the high-voltage motor auxiliary support (75) is fixed between the high-voltage motor (71) and the oil tank (3).

3. The dual stage dry oil free screw compressor of claim 1 wherein: a low-pressure-stage speed-increasing driving gear (621) and a low-pressure-stage speed-increasing driven gear (622) which are meshed with each other are arranged in the low-pressure-stage gear box (62), the low-pressure-stage speed-increasing driving gear (621) is connected with a motor output shaft in the low-pressure-stage motor (61), and the low-pressure-stage speed-increasing driven gear (622) is connected with the low-pressure-stage male rotor (67); the high-voltage-stage gear box (72) is internally provided with a high-voltage-stage speed-increasing driving gear and a high-voltage-stage speed-increasing driven gear which are meshed with each other, the high-voltage-stage speed-increasing driving gear is connected with a motor output shaft in the high-voltage-stage motor (71), and the high-voltage-stage speed-increasing driven gear is connected with a high-voltage-stage male rotor.

4. The dual stage dry oil free screw compressor of claim 1 wherein: the low-voltage motor (61) is provided with an oil inlet hole (611).

5. The dual stage dry oil free screw compressor of claim 1 wherein: the oil tank (3) is of a whole casting structure, and a cover plate of the oil tank (3) is arranged at the bottom of the oil tank (3).

6. The dual stage dry oil free screw compressor of claim 1 wherein: the bottom of the low-pressure gear box (62) is fixed at the top of the oil tank (3) through a bolt, and the bottom of the high-pressure gear box (72) is fixed at the top of the oil tank (3) through a bolt.

7. The dual stage dry oil free screw compressor of claim 4 wherein: the two-stage dry oil-free screw compressor has and has only one oil inlet hole (611).

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