Two-stage screw compressor

Abstract

The utility model discloses a two-stage screw compressor, which comprises a speed-changing gear box, a screw rod, a screw rod, a screw rod, a screw rod, a screw rod, a screw rod, a screw rod, a screw rod and a screw rod, the rotating speed of the main shaft gear is smaller than that of the driven gears and drives the two driven gears to rotate; the machine body comprises a first-stage screw rotor and a second-stage screw rotor which are arranged up and down; the first-stage screw rotor and the second-stage screw rotor are connected with the two driven gears correspondingly, so that the two driven gears drive the first-stage screw rotor and the second-stage screw rotor to rotate correspondingly. According to the technical scheme, the main shaft of the motor can be in a low-rotating-speed operation range, damage to components of the compressor is reduced, and meanwhile the structural size and the occupied area of the compressor are effectively reduced.

Description

Technical Field

[0001] This application relates to the field of refrigeration compressor technology, specifically to a two-stage screw compressor. Background Technology

[0002] Single-unit two-stage screw refrigeration compressors are widely used in cold chain logistics, food processing, pharmaceutical and chemical industries due to their safety, reliability and high efficiency at low temperatures.

[0003] However, existing open-type single-unit two-stage screw refrigeration compressors use high- and low-pressure side rotors arranged sequentially along the motor shaft, resulting in a very long compressor. Furthermore, most existing two-stage screw compressors use fixed-frequency motors to directly drive the compressor screw rotors, leading to lower rotor speeds. This results in a larger rotor size for the same displacement, consequently increasing the overall compressor size and footprint, thus limiting its suitability for space-constrained applications. Direct motor drive also increases the wear and tear on the compressor's shaft seals, hindering long-term continuous operation and further increasing maintenance costs for users.

[0004] Therefore, how to design a single-unit two-stage screw compressor that reduces the compressor size while improving the reliability and service life of the shaft seal components has become a problem that needs to be solved in this field. Summary of the Invention

[0005] In view of this, this application proposes a two-stage screw compressor, the compressor comprising:

[0006] A gearbox includes: a main shaft gear and two driven gears; the main shaft gear rotates at a speed less than the driven gears, and drives the two driven gears to rotate.

[0007] The machine body includes: a primary screw rotor and a secondary screw rotor arranged vertically; the primary screw rotor and the secondary screw rotor are respectively connected to two driven gears, so that the two driven gears drive the primary screw rotor and the secondary screw rotor to rotate respectively.

[0008] Preferably, the main shaft gear and the driven gear are helical gears.

[0009] Preferably, the gearbox further includes: a gearbox cover;

[0010] The gearbox cover is located outside the main shaft gear and the driven gear, and is fixedly connected to the outer shell of the machine body.

[0011] Preferably, the vertical arrangement includes:

[0012] The primary screw rotor is positioned above the secondary screw rotor.

[0013] Preferably, the body further includes: an intake end seat and an exhaust end seat;

[0014] The intake end seat is located above the body;

[0015] The exhaust end seat is located at the bottom of the machine body.

[0016] Further optimization:

[0017] The intake end seat is provided with the bearing of the first-stage screw rotor;

[0018] The exhaust end seat is provided with the bearing of the secondary screw rotor.

[0019] Further optimization:

[0020] The body also includes: a side exhaust port and a bottom exhaust port;

[0021] The air intake end seat also includes an air intake port.

[0022] More preferably, the compressor further includes: an intermediate body;

[0023] The intermediate body is disposed between the gearbox and the machine body, and the primary exhaust end and the secondary intake end of the machine body are connected through the intermediate body.

[0024] More preferably, the intermediate further includes: an air inlet;

[0025] The air inlet is connected to the primary exhaust end and the secondary intake end.

[0026] Preferably, the spindle gear is driven to rotate by a variable frequency motor.

[0027] This application provides a two-stage screw compressor, including a main shaft gear and two driven gears. The main shaft gear rotates at a speed lower than that of the driven gears, driving the two driven gears to rotate. In this application, the first-stage screw rotor and the second-stage screw rotor are arranged vertically, and the first-stage screw rotor and the second-stage screw rotor are respectively connected to the two driven gears, so that the two driven gears drive the first-stage screw rotor and the second-stage screw rotor to rotate respectively. According to the solution of this application, the motor main shaft can be kept in a low-speed operating range, which reduces damage to the compressor components and also effectively reduces the structural size and floor space of the compressor.

[0028] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0029] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application, and the illustrative embodiments and descriptions thereof are used to explain this application. In the drawings:

[0030] Figure 1 This is a side view of a preferred embodiment of the two-stage screw compressor of this application.

[0031] Figure 2 This is a schematic diagram of the internal structure of a two-stage screw compressor according to a preferred embodiment of this application.

[0032] Figure 3 A front cross-sectional view of a two-stage screw compressor according to a preferred embodiment of this application;

[0033] Figure 4 This is a schematic diagram of another side of the two-stage screw compressor according to a preferred embodiment of this application.

[0034] Attachment Number:

[0035] 1-Gearbox 1; 11-Main shaft gear; 12-Driven gear; 13-Gearbox cover;

[0036] 2-Main body; 21-First stage screw rotor; 22-Second stage screw rotor; 23-Intake end seat; 24-Exhaust end seat; 25-Intake port; 26-Side exhaust port; 27-Bottom exhaust port;

[0037] 3-Intermediate; 31-Gas inlet;

[0038] 4-Spindle;

[0039] 5-Shaft seal. Detailed Implementation

[0040] The technical solution of this application will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] First, the compressor in this application is a two-stage screw compressor. Two-stage means that the gas compression process inside the compressor is divided into two stages, typically achieved through different compression stages, each equipped with an independent screw rotor. The gas first enters the first stage, also known as the low-pressure stage or pre-stage, for initial compression. The compressed gas then enters the second stage, also known as the high-pressure stage or post-stage, for further compression until the required pressure is reached before being discharged.

[0042] Combination Figures 1 to 4 As shown, the two-stage screw compressor provided in this application includes a gearbox 1 and a housing 2. The gearbox 1 is used to transmit torque to two screw rotors in the housing 2, so that the two screw rotors compress the intake gas when rotating.

[0043] The gearbox 1 includes a main shaft gear 11 and two driven gears 12. The main shaft gear 11 is connected to the motor shaft 4 of the compressor and drives the two driven gears 12 to rotate via an external motor. The diameter of the main shaft gear 11 is larger than the diameter of the two driven gears 12, so that the rotational speed of the main shaft gear 11 is less than the rotational speed of the driven gears 12.

[0044] The machine body 2 includes a primary screw rotor 21 and a secondary screw rotor 22 arranged vertically. The primary screw rotor 21 and the secondary screw rotor 22 are respectively connected to two driven gears 12, so that the two driven gears 12 drive the primary screw rotor 12 and the secondary screw rotor 22 to rotate respectively.

[0045] First, this application utilizes the main shaft gear 11 and driven gear 12 with different rotational speeds in the gearbox 1 to accelerate the input speed of the motor main shaft 4, keeping it in a low-speed operating range without affecting the operation of the two screw rotors in the compressor body 2. In other words, this application uses the large gear on the motor shaft to drive the small gears on the two male rotors, which can relatively reduce the speed on the motor side without affecting the compressor's operation. For most open-type compressors, the shaft seal, as a key component preventing leakage between the motor main shaft and the gearbox cover, is very prone to leakage or damage at high speeds. This application, however, can reduce the leakage of the shaft seal 5 and extend its service life by lowering the speed of the motor-side main shaft 4.

[0046] Secondly, in this application, the primary screw rotor 21 and the secondary screw rotor 22 share a single housing 2 and are arranged vertically, preferably with the primary screw rotor 21 on top and the secondary screw rotor 22 on the bottom. Compared with the prior art where the two screw rotors are arranged horizontally in a straight line, this can effectively compress the internal space of the compressor and reduce the structural size and floor space of the compressor.

[0047] Furthermore, in this application, the gearbox 1 and the housing 2 are connected by an intermediate body 3, allowing the primary exhaust end and the secondary intake end of the housing 2 to communicate through the intermediate body 3. The primary exhaust end corresponds to the primary side of the compressor, i.e., the low-pressure side, and includes the primary exhaust port. The secondary intake end corresponds to the secondary side of the compressor, i.e., the high-pressure side, and includes the secondary intake port. Low-temperature, low-pressure gas enters the compressor from the primary intake port, i.e., the compressor's intake port, is compressed by the primary screw rotor 21 and the secondary screw rotor 22, and then its temperature and pressure are increased before it is discharged from the secondary exhaust port, i.e., the compressor's exhaust port.

[0048] Preferably, the intermediate body 3 further includes an air inlet 31, which is connected to the primary exhaust end and the secondary intake end and is located on the top of the intermediate body 3 to increase the cooling capacity by supplementing air.

[0049] In addition, the gearbox 1 also includes a gearbox cover 13, which is disposed outside the main shaft gear 11 and the driven gear 12 and is fixedly connected to the outer shell of the body 2, so that the gearbox 1, the body 2 and the outer shell area of ​​the intermediate body 3 are connected as a whole. Furthermore, a shaft seal 5 is disposed outside the gearbox cover 13 to seal the leakage channel between the motor main shaft 4 and the gearbox cover 13.

[0050] The body 2 also includes an intake end seat 23 and an exhaust end seat 24. The intake end seat 23 is located above the body 2 and houses the bearing for the primary screw rotor 21. The exhaust end seat 24 is located below the body 2 and houses the bearing for the secondary screw rotor 22. The intake end seat 23 has an intake port 25, while the exhaust end seat 24 functions as an exhaust-side end cap, with the exhaust port located elsewhere within the body 2.

[0051] To facilitate different connection methods of the unit, the exhaust port in this application includes: a side exhaust port 26 and a bottom exhaust port 27. Both exhaust ports are located in the lower region of the body 2, one on the side of the lower region of the body 2 and the other on the bottom surface of the body 2.

[0052] Preferably, the main shaft gear 11 is driven to rotate by a variable frequency motor, thereby adjusting the compressor's suction volume by changing the rotational speed of the two screw rotors using the variable frequency motor. That is, the main shaft 4 is driven by the variable frequency motor, and the primary screw rotor 21 and the secondary screw rotor 22 are driven to rotate synchronously through the gearbox 1 to adjust the compressor's capacity.

[0053] Preferably, the main shaft gear 11 and the driven gear 12 are helical gears, wherein the axial force of the secondary driven gear 12 offsets part of the axial force of the corresponding screw rotor, while the axial force of the primary driven gear 12 increases the axial force of the corresponding screw rotor, so that the bearings of the primary screw rotor 21 and the secondary screw rotor 22 can obtain a longer service life.

[0054] Preferably, the refrigerants used in this application include, but are not limited to: R717, R22, R507A, R404A, R134a, R245Fa, R1270, R290, etc.

[0055] This application provides a two-stage screw compressor, including a main shaft gear and two driven gears. The main shaft gear rotates at a speed lower than that of the driven gears, driving the two driven gears to rotate. In this application, the first-stage screw rotor and the second-stage screw rotor are arranged vertically, and the first-stage screw rotor and the second-stage screw rotor are respectively connected to the two driven gears, so that the two driven gears drive the first-stage screw rotor and the second-stage screw rotor to rotate respectively. According to the solution of this application, the motor main shaft can be kept in a low-speed operating range, which reduces damage to the compressor components and also effectively reduces the structural size and floor space of the compressor.

[0056] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0057] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0058] Furthermore, various different embodiments of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content disclosed by this invention.

Claims

1. A two-stage screw compressor, characterized in that, The compressor includes: A gearbox includes: a main shaft gear and two driven gears; the main shaft gear rotates at a speed less than the driven gears, and drives the two driven gears to rotate. The machine body includes: a primary screw rotor and a secondary screw rotor arranged vertically; the primary screw rotor and the secondary screw rotor are respectively connected to two driven gears, so that the two driven gears drive the primary screw rotor and the secondary screw rotor to rotate respectively.

2. The compressor according to claim 1, characterized in that, The main shaft gear and the driven gear are helical gears.

3. The compressor according to claim 1, characterized in that, The gearbox also includes: a gearbox cover; The gearbox cover is located outside the main shaft gear and the driven gear, and is fixedly connected to the outer shell of the machine body.

4. The compressor according to claim 1, characterized in that, The vertical arrangement includes: The primary screw rotor is positioned above the secondary screw rotor.

5. The compressor according to claim 1, characterized in that, The body also includes: an intake end seat and an exhaust end seat; The intake end seat is located above the body; The exhaust end seat is located at the bottom of the machine body.

6. The compressor according to claim 5, characterized in that: The intake end seat is provided with the bearing of the first-stage screw rotor; The exhaust end seat is provided with the bearing of the secondary screw rotor.

7. The compressor according to claim 6, characterized in that: The body also includes: a side exhaust port and a bottom exhaust port; The air intake end seat also includes an air intake port.

8. The compressor according to any one of claims 1-7, characterized in that, The compressor also includes: an intermediate; The intermediate body is disposed between the gearbox and the machine body, and the primary exhaust end and the secondary intake end of the machine body are connected through the intermediate body.

9. The compressor according to claim 8, characterized in that, The intermediate also includes: an air inlet; The air inlet is connected to the primary exhaust end and the secondary intake end.

10. The compressor according to claim 1, characterized in that, The main shaft gear is driven to rotate by a variable frequency motor.

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