A screw compressor with two-stage compression

Abstract

This invention discloses a screw compressor with internal and external two-stage compression, belonging to the technical field of screw compressors. The screw compressor includes: a housing containing an outer compression chamber, comprising a male rotor and a female rotor; both ends of the male rotor are rotatably mounted on the inner wall of the outer compression chamber, and the male rotor has an inner cavity with a helical direction opposite to that of the male rotor. The inner cavity of the male rotor contains a first inner rotor capable of meshing with the inner cavity of the male rotor, both ends of which pass through the inner cavity of the male rotor and are rotatably mounted on the housing; both ends of the female rotor are rotatably mounted on the inner wall of the outer compression chamber and mesh with the male rotor. The internal and external compression forces are opposite, and the axial forces and radial forces cancel each other out during the internal and external compression processes, which helps reduce vibration and noise, while also improving the service life of the entire screw compressor with internal and external two-stage compression.

Description

Technical Field

[0001] This invention relates to the field of screw compressor technology, and more specifically to a screw compressor with internal and external two-stage compression. Background Technology

[0002] A screw compressor is a positive displacement rotary compressor used to obtain high-pressure gases. It is widely used in mining, power, metallurgy, construction, machinery and refrigeration. Screw compressors inherit the advantages of rotary machinery, such as long service life, low noise, low vibration, stable operation and no surge. At the same time, they have the characteristics of simple structure and no vulnerable parts such as intake and exhaust valves. Therefore, they are the core components of high-pressure gas transmission, refrigeration, waste heat recovery and other systems.

[0003] Traditional twin-screw compressors typically have only one axial compression process, requiring larger equipment to achieve a sufficiently high compression ratio. Furthermore, the female and male rotors of a twin-screw compressor are subjected to the force of high-pressure gas, causing axial misalignment during operation. This not only increases wear but also leads to increased noise and vibration, ultimately affecting the equipment's lifespan. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems in the prior art and provide a screw compressor with internal and external two-stage compression, which can reduce vibration and noise during the compression process, while improving the service life of the entire internal and external two-stage screw compressor.

[0005] This invention provides a screw compressor with internal and external two-stage compression, housed within a casing. The casing includes an external compression chamber comprising a male rotor and a female rotor. Both ends of the male rotor are rotatably mounted on the inner wall of the external compression chamber. The male rotor contains an inner cavity with a helical direction opposite to that of the male rotor. Within the inner cavity of the male rotor is a first inner rotor capable of meshing with the inner cavity of the male rotor. Both ends of the first inner rotor pass through the inner cavity of the male rotor and are rotatably mounted on the casing. Both ends of the female rotor are rotatably mounted on the inner wall of the external compression chamber and mesh with the male rotor. The machine body has an inner cavity for a female rotor that rotates in the opposite direction to the female rotor. Inside the female rotor cavity is a second inner rotor capable of meshing with it. Both ends of the second inner rotor pass through the female rotor cavity and are rotatably mounted on the machine body. The machine body has an intake port communicating with the outer compression chamber. One end of the machine body has a first connecting cavity that connects the outer compression chamber, the male rotor cavity, and the female rotor cavity. The other end of the machine body has an exhaust port that connects the male rotor cavity and the female rotor cavity to the outer surface of the machine body.

[0006] Preferably, the end of the first inner rotor extends out of the machine body, and this end is connected to the output end of the drive motor via a coupling.

[0007] Preferably, one end of the male rotor and the female rotor on the same side are respectively disposed on the inner wall of the outer compression chamber by a first sealing bearing, and the other end of the male rotor and the female rotor on the same side are respectively disposed on the sealing cover by a second sealing bearing. The sealing cover is fixed to the assembly port provided at the end of the machine body by a first bolt, and the first conductive cavity is disposed inside the sealing cover.

[0008] Preferably, one end of the first inner rotor and the second inner rotor on the same side are both mounted on the machine body via a third sealing bearing, and the other end of the first inner rotor and the second inner rotor on the same side are both mounted on the sealing cover via a fourth sealing bearing.

[0009] Preferably, the sealing cover is provided with a first end cap, which is fixedly connected to the sealing cover by a second bolt.

[0010] Preferably, the first end cap has a first protrusion on the side near the sealing cap, and the first protrusion abuts against the outer ring side of the fourth sealing bearing.

[0011] Preferably, a second end cap is provided on the end of the machine body away from the sealing cover, and the second end cap is fixedly connected to the machine body by a third bolt.

[0012] Preferably, the second end cap has a second protrusion on the side near the third sealing bearing, and the second protrusion abuts against the outer ring side of the third sealing bearing.

[0013] Preferably, the end of the first inner rotor extends out of the central hole provided on the first end cover.

[0014] Preferably, the second end cap is provided with a channel communicating with the exhaust port, the channel being able to discharge compressed gas.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: the inner cavities of the male rotor and the female rotor are screw-shaped, and the cavity wall shapes of the inner cavities of the male rotor and the female rotor satisfy the meshing relationship with the corresponding inner rotors, so that the inner cavity of the male rotor and the first inner rotor mesh with each other as outer rotors, and the inner cavity of the female rotor and the second inner rotor mesh with each other as outer rotors; the meshing of the male rotor and the female rotor allows the gas to be compressed axially along the first inner rotor between the meshing surface and the outer compression cavity, which is called external compression; the inner cavity of the male rotor and the first inner rotor The two rotors mesh with each other, forming a closed compression chamber for the compressed gas. The gas is compressed axially along the first inner rotor within this closed compression chamber, which is called internal compression. The inner chamber of the female rotor meshes with the second inner rotor, forming a closed compression chamber for the compressed gas. The gas is compressed axially along the second inner rotor within this closed compression chamber, which is called internal compression. Since the helix of the first inner rotor is opposite in direction to the helix of the male rotor, and the helix of the second inner rotor is opposite in direction to the helix of the female rotor, the directions of both internal compressions are opposite to the compression direction of the external compression.

[0016] Gas enters the outer compression chamber through the intake port. The male rotor and female rotor mesh with each other, causing the meshing surfaces to continuously push the gas to the right, compressing the gas into the first conducting chamber. At the same time, because the inner cavity of the male rotor meshes with the first inner rotor, and the inner cavity of the female rotor meshes with the second inner rotor, both meshing surfaces push the compressed gas in the first conducting chamber to the left. Finally, the compressed gas is discharged from the exhaust port, completing the two-stage gas compression.

[0017] During external compression, the left side is the low-pressure end and the right side is the high-pressure end; during internal compression, the left side is the high-pressure end and the right side is the low-pressure end. Thus, the internal compression force and the external compression force are opposite. The axial forces and radial forces between the internal and external compression processes cancel each other out, which helps to reduce vibration and noise, and at the same time improves the service life of the entire internal and external two-stage compression screw compressor. Attached Figure Description

[0018] Figure 1 This is a horizontal sectional view of the present invention;

[0019] Figure 2 This is a vertical sectional view at the axis of the first inner rotor of the present invention;

[0020] Figure 3 This is a left view of the body of the present invention;

[0021] Figure 4 This is a schematic diagram of the meshing of the male rotor and female rotor of the present invention;

[0022] Figure 5 This is a schematic diagram of the meshing cross-sections of the male rotor and female rotor of the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Male rotor, 2. Female rotor, 3. Male rotor inner cavity, 4. Female rotor inner cavity, 5. First inner rotor, 6. Second inner rotor, 7. Body, 11. Intake port, 12. External compression chamber, 13. First conduction chamber, 17. Exhaust port, 20. First sealed bearing, 21. Second sealed bearing, 22. Sealing cover, 23. First bolt, 24. Third sealed bearing, 25. Fourth sealed bearing, 26. First end cover, 27. Second bolt, 28. Second end cover, 29. Third bolt. Detailed Implementation

[0025] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] First Embodiment

[0027] This invention provides a screw compressor with internal and external two-stage compression, disposed within a housing 7, wherein the housing 7 has an external compression chamber 12, such as... Figures 1-5 The machine includes: a male rotor 1 and a female rotor 2; both ends of the male rotor 1 are rotatably mounted on the inner wall of the outer compression chamber 12, and the male rotor 1 has a male rotor inner cavity 3 with the opposite helical direction to the male rotor 1. The male rotor inner cavity 3 has a first inner rotor 5 that can mesh with the male rotor inner cavity 3, and both ends of the first inner rotor 5 pass through the male rotor inner cavity 3, and both ends of the first inner rotor 5 are rotatably mounted on the machine body 7; both ends of the female rotor 2 are rotatably mounted on the inner wall of the outer compression chamber 12, and the female rotor 2 meshes with the male rotor 1. The female rotor 2 has a female rotor inner cavity 4 with the opposite helical direction to the female rotor 2. The inner cavity 4 of the rotor is provided with a second inner rotor 6 that can mesh with the inner cavity 4 of the female rotor. Both ends of the second inner rotor 6 pass through the inner cavity 4 of the female rotor, and both ends of the second inner rotor 6 are rotatably mounted on the body 7. The body 7 is provided with an air intake 11 that communicates with the outer compression chamber 12. One end of the body 7 is provided with a first conductive cavity 13, which is used to communicate the outer compression chamber 12, the inner cavity 3 of the male rotor, and the inner cavity 4 of the female rotor. The other end of the body 7 is provided with an exhaust port 17 that communicates the inner cavity 3 of the male rotor and the inner cavity 4 of the female rotor with the outer surface of the body 7.

[0028] The male rotor cavity 3 and the female rotor cavity 4 are screw-shaped. The cavity wall shapes of the male rotor cavity 3 and the female rotor cavity 4 satisfy the meshing relationship with the corresponding inner rotor (male rotor cavity 3 or female rotor cavity 4), so that the male rotor cavity 3 and the first inner rotor 5 respectively act as outer rotors and mesh with each other as inner rotors, and also so that the female rotor cavity 4 and the second inner rotor 6 respectively act as outer rotors and mesh with each other as inner rotors; the male rotor 1 and the female rotor 2 mesh with each other, so that the gas can be compressed along the axial direction of the first inner rotor 5 between the meshing surface and the outer compression cavity 12, which is called external compression; the male rotor cavity 3 and the first inner rotor 5 mesh with each other as inner rotors. The inner rotors 5 mesh with each other, forming a closed compression chamber for compressed gas. Gas is compressed axially along the first inner rotor 5 within this closed compression chamber, a process called internal compression. The inner chamber 4 of the female rotor meshes with the second inner rotor 6, forming a closed compression chamber for compressed gas. Gas is compressed axially along the second inner rotor 6 within this closed compression chamber, a process called internal compression. Since the helix of the first inner rotor 5 is opposite in direction to the helix of the male rotor 1, and the helix of the second inner rotor 6 is opposite in direction to the helix of the female rotor 2, the directions of both internal compressions are opposite to the direction of external compression.

[0029] Gas enters the outer compression chamber 12 through the intake port 11. The male rotor 1 and female rotor 2 mesh with each other, causing the meshing surfaces to continuously push the gas to the right and compress the gas into the first conducting chamber 13. At the same time, since the inner chamber 3 of the male rotor meshes with the first inner rotor 5 and the inner chamber 4 of the female rotor meshes with the second inner rotor 6, both meshing surfaces push the compressed gas in the first conducting chamber 13 to the left. Finally, the compressed gas is discharged from the exhaust port 17, completing the two-stage gas compression.

[0030] like Figure 1 As shown, during the external compression process, the left side is the low-pressure end and the right side is the high-pressure end; during the internal compression process, the left side is the high-pressure end and the right side is the low-pressure end. Thus, the internal compression force and the external compression force are opposite, and the axial force and radial force between the internal and external compression processes cancel each other out. This helps to reduce vibration and noise, and at the same time improves the service life of the entire internal and external two-stage compression screw compressor.

[0031] Better, such as Figures 1-2 and Figure 4 The end of the first inner rotor 5 extends out of the body 7, and this end is connected to the output end of the drive motor via a coupling.

[0032] During operation, the drive motor drives the first inner rotor 5 to rotate through the coupling. The first inner rotor 5 meshes with the inner cavity 3 of the male rotor and drives the male rotor 1 to rotate. The male rotor 1 meshes with the female rotor 2 and drives the female rotor 2 to rotate. The inner cavity 4 of the female rotor meshes with the second inner rotor 6 and drives the second inner rotor 6 to rotate. The three sets of connections together form an external compression process and two internal compression processes. The external compression process is connected to the two internal compression processes and together completes two-stage compression.

[0033] Second Embodiment

[0034] Preferably, such as Figure 1 and Figure 4 The male rotor 1 and the female rotor 2 are both mounted on the inner wall of the outer compression chamber 12 via a first sealing bearing 20 at one end on the same side. The other end of the male rotor 1 and the female rotor 2 are both mounted on the sealing cover 22 via a second sealing bearing 21. The sealing cover 22 is fixed to the assembly port at the end of the machine body 7 by a first bolt 23. The first conductive cavity 13 is located inside the sealing cover 22.

[0035] The male rotor 1 and female rotor 2 can be installed on the inner wall of the outer compression chamber 12 through the assembly port, and a sealing gasket is also provided between the sealing cover 22 and the surface of the assembly port.

[0036] Preferably, such as Figure 1 and Figure 4 The first inner rotor 5 and the second inner rotor 6 are both mounted on the machine body 7 via a third sealing bearing 24, and the other ends of the first inner rotor 5 and the second inner rotor 6 are both mounted on the sealing cover 22 via a fourth sealing bearing 25.

[0037] Preferably, the sealing cover 22 is provided with a first end cover 26, and the first end cover 26 is fixedly connected to the sealing cover 22 by a second bolt 27; the end of the first inner rotor 5 extends out of the center hole provided on the first end cover 26; a first protrusion is provided on the side of the first end cover 26 near the sealing cover 22, and the first protrusion abuts against the outer ring side of the fourth sealing bearing 25.

[0038] The first protrusion on the first end cap 26 is used to restrict the fourth sealing bearing 25 and prevent the fourth sealing bearing 25 from moving or becoming loose.

[0039] Third Embodiment

[0040] Preferably, such as Figure 1 and Figure 4The first inner rotor 5 and the second inner rotor 6 are both mounted on the machine body 7 via a third sealing bearing 24 at one end on the same side, and the first inner rotor 5 and the second inner rotor 6 are both mounted on the sealing cover 22 via a fourth sealing bearing 25 at the other end on the same side. A second end cover 28 is provided on the end of the machine body 7 away from the sealing cover 22, and the second end cover 28 is fixedly connected to the machine body 7 by a third bolt 29. A second protrusion is provided on the side of the second end cover 28 near the third sealing bearing 24, and the second protrusion abuts against the outer ring side of the third sealing bearing 24.

[0041] The second protrusion on the second end cap 28 is used to restrict the third sealing bearing 24 and prevent the third sealing bearing 24 from moving or becoming loose.

[0042] Preferably, the second end cap 28 is provided with a channel communicating with the exhaust port 17, and the channel is capable of discharging compressed gas.

[0043] The method of using the screw compressor with internal and external two-stage compression of the present invention is as follows:

[0044] The drive motor drives the first inner rotor 5 to rotate through the coupling. Gas enters the outer compression chamber 12 through the intake port 11. The male rotor 1 and the female rotor 2 mesh with each other, so that the meshing surface and the outer compression chamber 12 continuously push the gas to the right, compressing the gas into the first conduction chamber 13. At the same time, since the inner chamber 3 of the male rotor meshes with the first inner rotor 5, and the inner chamber 4 of the female rotor also meshes with the second inner rotor 6, both meshing surfaces push the compressed gas in the first conduction chamber 13 to the left. Finally, the compressed gas is discharged from the exhaust port 17, completing the two-stage gas compression.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A screw compressor with internal and external two-stage compression, disposed within a housing (7), wherein the housing (7) has an external compression chamber (12), characterized in that, include: The male rotor (1) is rotatably mounted on the inner wall of the outer compression chamber (12) at both ends. The male rotor (1) is provided with a male rotor inner cavity (3) with the opposite spiral direction to the male rotor (1). The male rotor inner cavity (3) is provided with a first inner rotor (5) that can mesh with the male rotor inner cavity (3). Both ends of the first inner rotor (5) pass through the male rotor inner cavity (3), and both ends of the first inner rotor (5) are rotatably mounted on the machine body (7). The female rotor (2) is rotatably mounted on the inner wall of the outer compression chamber (12) at both ends, and the female rotor (2) meshes with the male rotor (1). The female rotor (2) is provided with a female rotor cavity (4) with the opposite spiral direction to the female rotor (2). The female rotor cavity (4) is provided with a second inner rotor (6) that can mesh with the female rotor cavity (4). Both ends of the second inner rotor (6) pass through the female rotor cavity (4), and both ends of the second inner rotor (6) are rotatably mounted on the machine body (7). The body (7) is provided with an air intake (11) communicating with the external compression chamber (12). One end of the body (7) is provided with a first connecting chamber (13) for communicating the external compression chamber (12), the male rotor inner cavity (3) and the female rotor inner cavity (4) with each other. The other end of the body (7) is provided with an exhaust port (17) for communicating the male rotor inner cavity (3) and the female rotor inner cavity (4) with the outer surface of the body (7). The end of the first inner rotor (5) extends out of the machine body (7), and this end is connected to the output end of the drive motor via a coupling; The male rotor (1) and the female rotor (2) are both mounted on the inner wall of the outer compression chamber (12) via a first sealed bearing (20) at one end on the same side. The other end of the male rotor (1) and the female rotor (2) are both mounted on the sealing cover (22) via a second sealed bearing (21). The sealing cover (22) is fixed to the assembly port at the end of the machine body (7) by a first bolt (23). The first conductive cavity (13) is located inside the sealing cover (22). The first inner rotor (5) and the second inner rotor (6) are both mounted on the machine body (7) via a third sealed bearing (24) at one end of the same side, and the first inner rotor (5) and the second inner rotor (6) are both mounted on the sealing cover (22) via a fourth sealed bearing (25); A second end cap (28) is provided on one end of the body (7) away from the sealing cover (22), and the second end cap (28) is fixedly connected to the body (7) by a third bolt (29); The second end cap (28) is provided with a channel that connects to the exhaust port (17), and the channel is capable of discharging compressed gas.

2. The screw compressor with internal and external two-stage compression as described in claim 1, characterized in that, The sealing cover (22) is provided with a first end cap (26), and the first end cap (26) is fixedly connected to the sealing cover (22) by a second bolt (27).

3. The screw compressor with internal and external two-stage compression as described in claim 2, characterized in that, The first end cap (26) has a first protrusion on the side near the sealing cap (22), and the first protrusion abuts against the outer ring side of the fourth sealing bearing (25).

4. The screw compressor with internal and external two-stage compression as described in claim 1, characterized in that, The second end cap (28) has a second protrusion on the side near the third sealed bearing (24), and the second protrusion abuts against the outer ring side of the third sealed bearing (24).

5. The screw compressor with internal and external two-stage compression as described in claim 2, characterized in that, The end of the first inner rotor (5) extends out of the central hole provided on the first end cover (26).

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