Segmented reverse rotor structure of two-stage compression oil injection screw compressor

Abstract

The invention discloses a segmented reverse rotor structure of a two-stage compression oil injection screw compressor. The segmented reverse rotor structure comprises a machine shell, a rotor and a rotor, the first-stage male rotor is rotatably installed in the first-stage compression chamber of the machine shell, and one end of a rotor shaft of the first-stage male rotor penetrates through a partition piece of the first-stage compression chamber and a partition piece of a second-stage compression chamber of the machine shell and extends into the second-stage compression chamber; the first-stage female rotor is rotatably mounted in the first-stage compression chamber and engaged with the first-stage male rotor; the second-stage male rotor is rotatably mounted in the second-stage compression cavity and coaxially connected to a rotor shaft of the first-stage male rotor, and the spiral direction of the second-stage male rotor is opposite to that of the first-stage male rotor; the second-stage female rotor is rotatably mounted in the second-stage compression chamber and engaged with the second-stage male rotor; and the cooling chamber is connected with a cooler through the oil return pipe. The two-stage screw compressor solves the problems that in an existing two-stage screw compressor, the load of axial bearings of the first-stage male rotor and the second-stage male rotor is large, and the service life is short.

Description

Technical Field

[0001] This invention relates to the field of air compressor technology, and specifically to a segmented reverse rotor structure for a two-stage compression oil-injected screw compressor. Background Technology

[0002] Screw compressors, also known as screw compressors, are divided into single-screw compressors and twin-screw compressors. For example... Figure 1 As shown, a typical two-stage screw compressor is driven by a motor via a gear shaft D. A main gear C is mounted on gear shaft D. The main gear then drives a primary auxiliary gear B mounted on the primary male rotor A and a secondary auxiliary gear E mounted on the secondary male rotor F. The rotation of the primary male rotor A drives the primary female rotor. The rotation of the secondary male rotor F drives the secondary female rotor. Both sets of male and female rotors operate simultaneously to achieve two-stage compression. The primary rotor draws in air from position a, compresses it to an intermediate pressure, and discharges it from position b. The compressed air exerts a rightward axial force e on the rotor. The secondary rotor draws in compressed air discharged from position b from position c, compresses it in two stages, and then discharges it from position d. The compressed air exerts a rightward axial force f on the rotor. Several radial and axial bearings are installed at the discharge ends of both the primary and secondary male rotors for positioning. The compressed air does not separate lubricating oil during its movement from position b to position c, reducing the effective intake volume of the secondary stage. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, a segmented reverse rotor structure for a two-stage compression oil-injected screw compressor is provided to solve the problem of large load and short service life of the axial bearings of the first and second stage male rotors in existing two-stage screw compressors.

[0004] To achieve the above objectives, a segmented reverse rotor structure for a two-stage compression oil-injected screw compressor is provided, comprising: The housing contains a primary compression chamber, a secondary compression chamber, and a cooling chamber. The primary and secondary compression chambers are arranged side by side. The housing has an air inlet connected to the primary compression chamber and an exhaust outlet connected to the secondary compression chamber. The cooling chamber is connected to the primary compression chamber through an exhaust inlet and to the secondary compression chamber through an exhaust outlet. A primary male rotor is rotatably mounted in the primary compression chamber, and one end of the rotor shaft of the primary male rotor passes through the partition between the primary compression chamber and the secondary compression chamber and extends into the secondary compression chamber. The primary female rotor is rotatably mounted in the primary compression chamber and meshes with the primary male rotor; The secondary male rotor is rotatably mounted in the secondary compression chamber and coaxially connected to the rotor shaft of the primary male rotor. The helical direction of the secondary male rotor is opposite to that of the primary male rotor. The secondary female rotor is rotatably mounted in the secondary compression chamber and meshes with the secondary male rotor. The axial reaction force of the compressed air on the primary male rotor and the secondary male rotor is opposite in direction when they rotate. The cooling chamber is connected to a cooler via the return oil pipe, and the output end of the cooler is connected to the primary compression chamber.

[0005] Furthermore, the partition includes a radial partition and an axial partition formed within the housing. The radial partition is arranged along the radial direction of the housing. One side of the radial partition forms the primary compression chamber between one end of the housing and the other side of the radial partition forms the axial partition between the other side of the radial partition and the other end of the housing. One side of the axial partition, together with the radial partition and the other end of the housing, forms the secondary compression chamber. The other side of the axial partition, together with the radial partition and the other end of the housing, forms the cooling chamber.

[0006] Furthermore, the radial partition has a shaft hole, and the rotor shaft is rotatably mounted in the shaft hole.

[0007] Furthermore, the rotor shaft is rotatably mounted in the shaft hole via an angular contact ball bearing, and a sealing baffle is installed between the opening of the shaft hole and the rotor shaft.

[0008] Furthermore, the number of angular contact ball bearings is two, and the two angular contact ball bearings are arranged face to face.

[0009] Furthermore, the sealing baffle is equipped with an elastic element, which is pre-tightened to the outer ring of the angular contact ball bearing.

[0010] Furthermore, the elastic element is a spring.

[0011] Furthermore, a nozzle for spraying atomized low-temperature cooling oil is installed inside the outlet.

[0012] The beneficial effect of the present invention is that the segmented reverse rotor structure of the two-stage compression oil-injected screw compressor of the present invention generates opposite axial forces (i.e., left axial force F1 and right axial force F2) that cancel each other out, so that the axial force of the assembled first-stage male rotor and second-stage male rotor is much smaller, which effectively reduces the load on the axial bearing of the rotor shaft, extends the service life of the bearing, and reduces maintenance costs. Attached Figure Description

[0013] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of an existing two-stage screw compressor.

[0014] Figure 2 This is a schematic diagram of the segmented reverse rotor structure of a two-stage compression oil-injected screw compressor according to an embodiment of the present invention.

[0015] Figure 3 This is a cross-sectional view of the segmented reverse rotor structure of a two-stage compression oil-injected screw compressor according to an embodiment of the present invention.

[0016] Figure 4 for Figure 3 A cross-sectional view along the GG direction.

[0017] Figure 5 This is a partially enlarged schematic diagram of the axial hole of the radial partition in an embodiment of the present invention.

[0018] Figure label: First-stage male rotor A, first-stage auxiliary gear B, main gear C, gear shaft D, second-stage auxiliary gear E, second-stage male rotor F, position a, position b, position c, position d, rightward axial force e, rightward axial force f; 1. Housing, 11. Radial baffle, 111. Sealing baffle, 112. Angular contact ball bearing, 13. Elastic element, 12. Axial baffle, g. Cooling chamber, h. Air inlet, i. Exhaust outlet, j. Primary male rotor 2, rotor shaft 21; Primary female rotor 3; Secondary male rotor 4; Secondary female rotor 5; Left axial force F1, right axial force F2. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] Reference Figures 2 to 5As shown, the present invention provides a segmented reverse rotor structure for a two-stage compression oil-injected screw compressor, comprising: a housing 1, a first-stage male rotor 2, a first-stage female rotor 3, a second-stage male rotor 4, a second-stage female rotor 5, and an oil return pipe.

[0022] In this embodiment, the housing is generally cylindrical and horizontally arranged. A primary compression chamber, a secondary compression chamber, and a cooling chamber g are formed within the housing 1. The primary and secondary compression chambers are arranged side-by-side in the axial direction of the housing. The cooling chamber is arranged side-by-side with the secondary compression chamber in the horizontal direction.

[0023] Combination Figure 3 and Figure 4 As shown, the housing 1 has an air inlet h and an exhaust outlet i. The air inlet h is connected to the primary compression chamber. The exhaust outlet i is connected to the secondary compression chamber.

[0024] Cooling chamber g is connected to the primary compression chamber via an inlet. Cooling chamber g is connected to the secondary compression chamber via an outlet j.

[0025] The primary male rotor 2 is rotatably mounted in the primary compression chamber. One end of the rotor shaft 21 of the primary male rotor 2 passes through the partition between the primary compression chamber and the secondary compression chamber and extends into the secondary compression chamber.

[0026] The primary female rotor 3 is rotatably mounted in the primary compression chamber. The primary female rotor 3 meshes with the primary male rotor 2.

[0027] The secondary male rotor 4 is rotatably mounted in the secondary compression chamber and coaxially connected to the rotor shaft 21 of the primary male rotor 2. The helical direction of the secondary male rotor 4 is opposite to that of the primary male rotor 2.

[0028] The secondary female rotor 5 is rotatably mounted in the secondary compression chamber. The secondary female rotor 5 meshes with the secondary male rotor 4. The axial reaction forces of the compressed air acting on the primary male rotor 2 and the secondary male rotor 4 during rotation are in opposite directions.

[0029] Cooling chamber g is connected to a cooler via a return oil pipe. The cooler's output is connected to the primary compression chamber.

[0030] After the rotor shaft of the primary male rotor is driven to rotate by the drive mechanism, air from outside the casing is drawn into the primary compression chamber of the casing through the air inlet h. Simultaneously, cooling oil cooled by the cooler is sprayed into the primary compression chamber from the output end of the cooling chamber. In the primary compression chamber, the air mixed with cooling oil is compressed to an intermediate pressure under the pressure of the primary male and female rotors and discharged into the cooling chamber through the outlet. The compressed air mixed with cooling oil impacts the outer wall of the cooling chamber, i.e., the secondary compression chamber, causing the cooling oil to separate (coarse separation). The separated cooling oil flows to the bottom of the cooling chamber and is discharged into the cooler through the oil return pipe. The cooling oil is cooled and then sprayed back into the primary compression chamber for reuse; this portion of cooling oil does not enter the secondary compression chamber. The compressed air separated from the cooling oil in the cooling chamber is discharged into the secondary compression chamber through the outlet, where it is further compressed under the pressure of the secondary male and female rotors and discharged through the exhaust port.

[0031] The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor of the present invention has a first-stage and second-stage rotor that generate opposite axial forces (i.e., left axial force F1 and right axial force F2) that cancel each other out. This makes the axial force of the assembled first-stage male rotor and second-stage male rotor much smaller, effectively reducing the load on the axial bearing of the rotor shaft, extending the service life of the bearing, and reducing maintenance costs.

[0032] A radial partition 11 is formed inside the housing 1. The radial partition 11 is arranged along the radial direction of the housing 1. A primary compression chamber is formed between one side of the radial partition 11 and one end of the housing 1. An axial partition 12 is formed between the other side of the radial partition 11 and the other end of the housing 1.

[0033] A secondary compression chamber is formed by enclosing one side of the axial partition 12 with the radial partition 11 and the other end of the housing 1.

[0034] The other side of the axial partition 12 and the other end of the radial partition 11 and the housing 1 form a cooling chamber g.

[0035] Combination Figure 5 As shown, the radial partition 11 has a shaft hole. The rotor shaft 21 is rotatably mounted in the shaft hole.

[0036] The rotor shaft 21 is rotatably mounted in the shaft hole via an angular contact ball bearing 112. A sealing baffle 111 is installed between the opening of the shaft hole and the rotor shaft 21.

[0037] There are two angular contact ball bearings 112. The two angular contact ball bearings 112 are arranged face to face.

[0038] A resilient element 13 is mounted on the sealing baffle 111. The resilient element 13 is supported on the outer ring of the angular contact ball bearing 112.

[0039] The elastic element 13 is a spring. In this embodiment, the elastic element is a helical spring. There are multiple elastic elements. The multiple elastic elements are spaced apart along the circumferential direction of the shaft hole.

[0040] Preferably, multiple elastic elements are arranged at equal intervals along the circumferential direction of the shaft hole.

[0041] In this embodiment, a nozzle for spraying atomized low-temperature cooling oil is installed in the outlet j. The atomized cooling oil is mixed with compressed air and then subjected to secondary compression by the secondary male rotor and the secondary female rotor to increase the pressure.

[0042] The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor of this invention arranges the primary and secondary male rotors in an in-line configuration. The primary and secondary male rotors are assembled together in a coaxial back-to-back arrangement. The primary and secondary female rotors are installed back-to-back respectively. Bearings are installed at various shaft ends of the rotors for rotor positioning. The secondary male rotor has a central hole and is heat-fitted onto the extension shaft of the primary male rotor shaft. The shaft and hole dimensions are interference fit, and a flat key is installed in the middle to prevent rotor slippage during rotation.

[0043] At each end of the primary and secondary male rotor shaft is a cylindrical roller bearing to bear the radial force generated by the high-pressure gas during operation. Two face-to-face angular contact ball bearings are mounted in the middle of the rotor shaft to bear the axial forces in both directions under different operating conditions. Springs are installed on the outer rings of each angular contact ball bearing to apply a preload. A sealing baffle is installed in the middle of the primary and secondary rotors to prevent high-pressure air leakage to the low-pressure end.

[0044] The primary rotor draws air in through the inlet, compresses it to an intermediate pressure, and discharges it into the cooling chamber through the outlet. The oil-laden compressed air impacts the inner wall of the cooling chamber (i.e., the outer wall of the secondary compression chamber), creating a separation of the cooling oil. The separated cooling oil descends to the bottom of the cooling chamber and is cooled via the return oil pipe before being sprayed back into the primary compression chamber for reuse. Subsequently, the compressed air in the cooling chamber continues to be drawn into the secondary compression chamber by the secondary rotor through the outlet. An oil injection line and nozzle are located at the outlet to inject atomized low-temperature cooling oil, reducing the intake temperature of the secondary compression chamber and improving insulation efficiency. After secondary compression, the compressed air is discharged from the exhaust port of the casing, completing the entire process of a two-stage compression oil-injected screw compressor from intake to exhaust.

[0045] Continue to combine Figure 4The helical direction of the secondary rotor is opposite to that of the primary rotor. Therefore, the compressed air generates a leftward axial force F1 on the primary rotor and a rightward axial force F2 on the secondary rotor. The two axial forces cancel each other out to effectively reduce the load on the axial bearing.

[0046] The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor of the present invention can reduce the axial force generated by high-pressure air on the male rotor at the intake end during operation. The first and second stage male rotors are installed back to back, and the axial forces cancel each other out, reducing the load on the axial bearing and improving the bearing service life.

[0047] The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor of the present invention drives a rotor shaft through a drive mechanism (such as a motor), which can simultaneously drive the operation of two sets of rotors in the first and second stages. This changes the conventional two-stage compressor mode that requires gear and gear shaft transmission, reduces the number of parts used, eliminates gear pair friction and lubrication loss, and improves transmission efficiency.

[0048] The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor of the present invention adopts intermediate oil injection atomization cooling technology, which reduces the intake temperature of the second stage compression and improves the insulation efficiency.

[0049] The innovative design of the segmented reverse rotor structure of the two-stage compression oil-injected screw compressor of this invention achieves the characteristics of "two-stage compression and two-stage separation". The oil separated by the first stage compression is cooled and then injected into the first stage, and does not enter the second stage. This reduces the disturbance loss of the cooling oil and the energy loss of the high-pressure oil, thereby improving energy efficiency.

[0050] The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor of this invention assembles the two-stage male rotor, which typically requires separate installation, onto the first-stage male rotor. To ensure the coaxiality of the first and second-stage rotors, the end shaft of the first-stage male rotor is lengthened, and a circular hole is machined into the center of the second-stage male rotor. The coaxiality requirement of the shaft and hole with respect to the rotor axis is 0.02mm. The diameter tolerance is an interference fit. During installation, the second-stage male rotor needs to be heated to 120°C and then pressed onto the first-stage male rotor shaft using hydraulic tools to create a large coefficient of friction, preventing slippage and wear between the rotors during operation. Keyways are machined into both the first-stage and second-stage male rotor shafts and holes. Flat keys need to be hammered into the rotors before assembly to ensure synchronous rotation of the first and second-stage male rotors. The baffle in the middle of the rotor has two shaft diameter holes through which the first-stage male rotor shaft and the second-stage female rotor shaft pass. The baffle has a second-stage axial exhaust port machined near the second-stage exhaust end face to control the exhaust angle of the second stage.

[0051] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A segmented reverse rotor structure for a two-stage compression oil-injected screw compressor, characterized in that, include: The housing contains a primary compression chamber, a secondary compression chamber, and a cooling chamber. The primary and secondary compression chambers are arranged side by side. The housing has an air inlet connected to the primary compression chamber and an exhaust outlet connected to the secondary compression chamber. The cooling chamber is connected to the primary compression chamber through an exhaust inlet and to the secondary compression chamber through an exhaust outlet. A primary male rotor is rotatably mounted in the primary compression chamber, and one end of the rotor shaft of the primary male rotor passes through the partition between the primary compression chamber and the secondary compression chamber and extends into the secondary compression chamber. The primary female rotor is rotatably mounted in the primary compression chamber and meshes with the primary male rotor; The secondary male rotor is rotatably mounted in the secondary compression chamber and coaxially connected to the rotor shaft of the primary male rotor. The helical direction of the secondary male rotor is opposite to that of the primary male rotor. The secondary female rotor is rotatably mounted in the secondary compression chamber and meshes with the secondary male rotor. The axial reaction force of the compressed air on the primary male rotor and the secondary male rotor is opposite in direction when they rotate. The cooling chamber is connected to a cooler via the return oil pipe, and the output end of the cooler is connected to the primary compression chamber.

2. The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor according to claim 1, characterized in that, The partition includes a radial partition and an axial partition formed inside the housing. The radial partition is arranged along the radial direction of the housing. One side of the radial partition forms the primary compression chamber between one end of the housing and the other side of the radial partition forms the axial partition between the other side of the radial partition and the other end of the housing. One side of the axial partition, together with the radial partition and the other end of the housing, forms the secondary compression chamber. The other side of the axial partition, together with the radial partition and the other end of the housing, forms the cooling chamber.

3. The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor according to claim 2, characterized in that, The radial partition has a shaft hole, and the rotor shaft is rotatably mounted in the shaft hole.

4. The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor according to claim 3, characterized in that, The rotor shaft is rotatably mounted in the shaft hole via an angular contact ball bearing, and a sealing baffle is installed between the opening of the shaft hole and the rotor shaft.

5. The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor according to claim 4, characterized in that, The number of angular contact ball bearings is two, and the two angular contact ball bearings are arranged face to face.

6. The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor according to claim 5, characterized in that, The sealing baffle is equipped with an elastic element, which is supported on the outer ring of the angular contact ball bearing.

7. The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor according to claim 6, characterized in that, The elastic element is a spring.

8. The segmented reverse rotor structure of the two-stage compression oil-injected screw compressor according to claim 1, characterized in that, The outlet is equipped with a nozzle for spraying atomized low-temperature cooling oil.

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