A two-stage oil-injected screw compressor

Abstract

The present application relates to a kind of two-stage oil injection screw compressor, including primary compressor, secondary compressor, gear box and interstage structure, the primary compressor and secondary compressor are connected on the gear box and are located the same side of gear box, the interstage structure is used to communicate the exhaust end of primary compressor and the intake end of secondary compressor, the compression chamber of primary compressor is provided with a primary oil injection port;The interstage baffle is arranged between the interstage structure and gear box, the lubricating oil gas passage is arranged between the interstage baffle and the top surface in gear box, the interstage structure and the upper portion of gear box are communicated by the lubricating oil gas passage.Primary compressor discharges oil-gas mixture, only a part of the oil-gas mixture enters the gear box to lubricate gear, the impact to gear is small, and the vibration and noise of the whole compressor are also small.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of two-stage oil-injected screw compressors. BACKGROUND

[0002] The conventional two-stage oil-injected screw compressor generally adopts the structure that the primary compressor and the secondary compressor are arranged in parallel, the primary compressor and the secondary compressor are connected to the gear box, the inter-stage structure is arranged between the primary compressor and the secondary compressor, the working gas is sucked into the primary compressor from the air inlet and is compressed by the primary compressor, and then the working gas enters the secondary compressor through the inter-stage structure and is compressed by the secondary compressor and is discharged from the air outlet.

[0003] In order to simplify the oil circuit design of the two-stage oil-injected screw compressor, the conventional two-stage oil-injected screw compressor generally guides the oil-gas mixture flowing out of the inter-stage structure into the gear box to lubricate the transmission gears in the gear box, and then guides the oil-gas mixture into the secondary compressor to be compressed by the secondary compressor, so that the oil injection circuit for each transmission gear in the gear box is not needed, as described in the Chinese patent with the application number 200610103120.X and the patent name "two-stage screw compressor". The transmission gears in the gear box only need a small amount of lubricating oil, but the oil-gas mixture flowing out of the inter-stage structure has a large pressure and a large gas volume, and the direct guidance of the oil-gas mixture into the gear box will cause a large impact on the gears and greatly increase the vibration and noise of the compressor.

[0004] In order to reduce the impact of the oil-gas mixture on the gears and reduce the vibration and noise of the compressor on the basis of simplifying the oil circuit design, the present application improves the structure of the two-stage oil-injected screw compressor of the prior art. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a two-stage oil-injected screw compressor, which uses the oil-gas mixture flowing out of the inter-stage structure to lubricate each transmission gear in the gear box, so that the oil circuit design is simplified, the impact of the oil-gas mixture on the gears is reduced, and the vibration and noise of the compressor are reduced.

[0006] The technical solution of the present application is to provide a two-stage oil-injected screw compressor, which comprises a primary compressor, a secondary compressor, a gear box and an inter-stage structure, the primary compressor and the secondary compressor are connected to the gear box and are located on the same side of the gear box, the inter-stage structure is used to connect the air outlet of the primary compressor and the air inlet of the secondary compressor, and a primary oil injection port is arranged in the compression chamber of the primary compressor; an inter-stage baffle is arranged between the inter-stage structure and the gear box, a lubricating oil-gas passage is arranged between the inter-stage baffle and the top surface of the gear box, and the upper part of the inter-stage structure and the gear box are connected through the lubricating oil-gas passage.

[0007] Compared with the prior art, the two-stage oil-injected screw compressor has the following advantages: during operation, working gas is sucked from the gas inlet of the primary compressor host and compressed into medium-pressure gas, and then enters the inter-stage structure, at this time, part of the medium-pressure gas enters the gear box through the lubricating oil gas passage, and the other part of the medium-pressure gas enters the secondary compressor host and is compressed into high-pressure gas, and then is discharged from the gas outlet of the compressor; since the compression chamber of the primary compressor host is provided with a primary oil injection port, the working gas can be injected into the compression chamber of the primary compressor host through the primary oil injection port to cool the primary screw rotor, and the medium-pressure gas discharged from the primary compressor host is an oil-gas mixture, part of which enters the gear box to lubricate each transmission gear in the gear box, so that the oil injection passage for each transmission gear in the gear box can be omitted, and the oil passage design of the compressor is simplified; since only part of the oil-gas mixture enters the gear box, the impact of the oil-gas mixture on the gear can be reduced, and the vibration and noise of the compressor as a whole can be reduced.

[0008] Preferably, at least one inter-stage oil injection port is arranged in the inter-stage structure, and the inter-stage oil injection port is used for injecting cooling lubricating oil into the inter-stage structure. With this structure, the oil-gas mixture entering the inter-stage structure can be cooled by injecting cooling lubricating oil into the inter-stage structure through the inter-stage oil injection port, so that the oil-gas mixture can better cool and lubricate each transmission gear in the gear box after entering the gear box.

[0009] Preferably, the inter-stage oil injection ports are all located in the lubricating oil gas passage. With this structure, the cooling lubricating oil injected through the inter-stage oil injection ports can all enter the inter-stage structure and contact the oil-gas mixture in the inter-stage structure, thereby improving the cooling effect.

[0010] Preferably, the inter-stage oil injection ports are located on the side wall of the inter-stage structure. With this structure, the inter-stage oil injection ports can be conveniently arranged, and the inter-stage oil injection ports can be integrally formed with the inter-stage structure or arranged on the inner side wall of the inter-stage structure by welding or other connection methods.

[0011] Preferably, a cooling oil passage pipe is arranged above the inter-stage baffle, the cooling oil passage pipe extends into the lubricating oil gas passage, and the inter-stage oil injection ports are all arranged on the pipe wall of the cooling oil passage pipe. With this structure, the cooling lubricating oil injected through the inter-stage oil injection ports can fully contact the oil-gas mixture in the inter-stage structure, and the cooling effect is good.

[0012] Preferably, an oil return channel is provided between the interstage baffle and the bottom surface of the gearbox, and the interstage structure is connected to the lower part of the gearbox through the oil return channel. With this structure, the oil return channel allows the lubricating oil in the gearbox to flow back into the interstage structure, and then into the compression chamber of the secondary compressor, which is beneficial for cooling the secondary screw rotor and facilitates the recycling and reuse of lubricating oil.

[0013] Preferably, the left and right sidewalls and bottom of the interstage baffle are connected to the inner wall of the gearbox, and an oil return hole is provided at the lower part of the interstage baffle. The interstage structure is connected to the lower part of the gearbox through the oil return hole. With this structure, only the oil return hole is provided to allow the lubricating oil in the gearbox to flow back into the interstage structure, avoiding excessive suction force on the gears in the gearbox due to the excessively large intake port of the secondary compressor on the gearbox cavity, thereby avoiding excessive vibration of the gears. The oil return hole is located at the lower part of the gearbox rather than the bottom of the gearbox, so that the bottom of the gearbox can store a certain level of lubricating oil to lubricate the gears.

[0014] Preferably, the top of the interstage baffle is connected to the inner wall of the gearbox, and a lubricating oil vent is provided on the upper part of the interstage baffle, which serves as the lubricating oil vent channel. With this structure, the interstage baffle is connected to the inner wall of the gearbox on all four sides, and only the lubricating oil vent is provided to allow a portion of the oil-gas mixture within the interstage structure to enter the gearbox and lubricate the various transmission gears. This avoids the excessive impact on the gears caused by a large cross-sectional area of ​​the lubricating oil vent channel, thus reducing the overall vibration and noise of the compressor. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the two-stage oil-injected screw compressor of the present invention.

[0016] Figure 2 This is a schematic diagram of the cylinder structure of the two-stage oil-injected screw compressor of the present invention.

[0017] Figure 3 for Figure 2 The front view.

[0018] As shown in the figure: 1. Cylinder, 2. First-stage compression chamber, 3. Second-stage compression chamber, 4. Gear chamber, 5. Interstage channel, 6. Interstage baffle, 7. Interstage oil injection port, 8. Oil return hole, 9. First-stage screw rotor, 10. Second-stage screw rotor, 11. Air inlet, 12. Exhaust port. Detailed Implementation

[0019] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements.

[0020] In the accompanying drawings, the thickness, size, and shape of the objects have been slightly exaggerated for illustrative purposes. The drawings are for illustrative purposes only and are not drawn to scale.

[0021] It should also be understood that the terms "comprising," "having," "including," and "containing," when used in this specification, indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof. Furthermore, when expressions such as "...at least one" appear after a list of listed features, they modify the entire listed feature, not individual elements in the list.

[0022] Example 1:

[0023] like Figure 1 and Figure 2 As shown, the two-stage oil-injected screw compressor of the present invention includes an integrally formed cylinder 1. The cylinder 1 is provided with a primary compression chamber 2, a secondary compression chamber 3, an interstage channel 5, and a gear cavity 4. The primary compression chamber 2 and the secondary compression chamber 3 are arranged vertically in parallel and are both located on the same side of the gear cavity 4. The interstage channel 5 is located between the primary compression chamber 2, the secondary compression chamber 3, and the gear cavity 4 and is connected to the primary compression chamber 2, the secondary compression chamber 3, and the gear cavity 4. The interstage channel 5 is the interstage structure that connects the primary compression chamber 2 and the secondary compression chamber 3.

[0024] A primary screw rotor 9 is installed within the primary compression chamber 2, constituting a primary compression unit. The air inlet 11 of the two-stage oil-injected screw compressor of this invention is located at the air inlet end of the primary compression unit. The air inlet 11 is located at the top of the primary compression chamber 2 and is spaced apart from the gear chamber 4. The exhaust end of the primary compression unit is connected to the interstage channel 5. A primary oil injection port (not shown) is also provided within the primary compression chamber 2. During operation of the primary compression unit, the primary oil injection port injects cooling and lubricating oil into the primary compression chamber 2 to cool the primary screw rotor 9.

[0025] The secondary compression chamber 3 is equipped with a secondary screw rotor 10, which constitutes a secondary compression host. The exhaust port 12 of the two-stage oil-injected screw compressor of the present invention is located at the exhaust end of the primary compression host. The exhaust port 12 is located on the side of the secondary compression chamber 3 and there is a distance between it and the gear chamber 4. The air intake end of the secondary compression host is also connected to the interstage channel 5.

[0026] The gear cavity 4 is provided with a main shaft, and a transmission gear set is arranged in the gear cavity 4, and the main shaft drives the first-stage screw rotor 9 and the second-stage screw rotor 10 through the transmission gear set.

[0027] An inter-stage baffle 6 is arranged between the inter-stage channel 5 and the gear cavity 4, the left and right side walls and the bottom of the inter-stage baffle 6 are connected with the cavity wall of the gear cavity 4, a gap is arranged between the top of the inter-stage baffle 6 and the top of the gear cavity 4, the gap forms a lubricating oil gas channel between the inter-stage channel 5 and the gear cavity 4, the lubricating oil gas channel includes the gap, and the upper portion of the inter-stage channel 5 is communicated with the upper portion of the gear cavity 4 through the lubricating oil gas channel. The lower portion of the inter-stage baffle is provided with an oil return hole 8, and the lower portion of the inter-stage channel 5 is communicated with the lower portion of the gear cavity 4 through the oil return hole 8. The main shaft and the gas inlet end of the second-stage screw rotor 10 are connected to the inter-stage baffle 6 through bearings.

[0028] The upper portion of the inter-stage channel 5 is provided with an inter-stage oil injection port 7, the inter-stage oil injection port 7 is arranged on the inner side wall of the inter-stage channel 5 and is also located in the lubricating oil gas channel, and cooling lubricating oil can be injected into the inter-stage channel 5 in the radial direction through the inter-stage oil injection port 7.

[0029] The working principle of the two-stage oil-injected screw compressor is as follows:

[0030] The first-stage compression host inhales working gas and performs first-stage compression on the working gas to discharge medium-pressure gas, the medium-pressure gas is an oil-gas mixture mixed with cooling lubricating oil in the first-stage compression cavity 2, the oil-gas mixture enters the inter-stage channel 5 from the gas outlet end of the first-stage compression host, and is cooled by the cooling lubricating oil injected by the inter-stage oil injection port 7.

[0031] Part of the oil-gas mixture cooled in the inter-stage channel 5 enters the upper portion of the gear cavity 4 through the lubricating oil gas channel and diffuses or drops downward to each transmission gear in the gear cavity 4, so as to lubricate and cool the transmission gear set in the gear cavity 4, and the bearings of the main shaft and the gas inlet end of the second-stage screw rotor 10 can also be lubricated and cooled, and the lubricating oil collected in the lower portion of the gear cavity 4 flows into the inter-stage channel 5 through the oil return hole 8.

[0032] The remaining part of the oil-gas mixture cooled in the inter-stage channel 5 is inhaled by the second-stage compression host, is compressed into high-pressure gas by the second-stage compression host, and is discharged from the gas outlet 12. The lubricating oil flowing into the inter-stage channel 5 through the oil return hole 8 also enters the second-stage compression cavity 3 and lubricates the second-stage screw rotor 10 together with the oil-gas mixture entering the second-stage compression cavity 3.

[0033] Since only a small part of the medium-pressure oil-gas mixture enters the gear cavity 4, the impact on the gears in the gear cavity 4 is small, so that the vibration and noise of the compressor as a whole are also small.

[0034] Example 2:

[0035] The two-stage oil-injected screw compressor of the embodiment is different from that of embodiment 1 in that a cooling oil passage pipe is arranged above the inter-stage baffle 6 in the two-stage oil-injected screw compressor of the embodiment, the cooling oil passage pipe crosses the lubricating oil and gas passage, and a plurality of inter-stage oil injection ports are uniformly arranged on the pipe wall of the cooling oil passage pipe, all the inter-stage oil injection ports can inject cooling lubricating oil into the inter-stage passage 5 in the radial direction, and thus the cooling effect of the oil and gas mixture in the inter-stage passage 5 can be improved.

[0036] Embodiment 3:

[0037] The two-stage oil-injected screw compressor of the embodiment is different from that of embodiment 1 in that the top of the inter-stage baffle 6 is also connected with the cavity wall of the gear cavity 4 in the two-stage oil-injected screw compressor of the embodiment, that is, the inter-stage passage 5 is blocked by the inter-stage baffle 6, but a plurality of lubricating oil and gas holes are arranged on the inter-stage baffle 6, the lubricating oil and gas holes are respectively opposite to the meshing points between the respective transmission gears in the gear cavity 4, and the inter-stage passage 5 and the gear cavity 4 are communicated through the respective lubricating oil and gas holes.

[0038] Part of the oil and gas mixture cooled in the inter-stage passage 5 can enter the gear cavity 4 through the respective lubricating oil and gas holes and precisely lubricate the meshing points between the respective transmission gears in the gear cavity 4, the lubricating and cooling effect of the gears is improved, the amount of the oil and gas mixture entering the gear cavity 4 is further reduced, the impact on the gears in the gear cavity 4 is reduced, and the vibration and noise of the whole compressor are reduced.

[0039] Embodiment 4:

[0040] The two-stage oil-injected screw compressor of the embodiment is different from that of embodiment 1 in that only the left and right side walls of the inter-stage baffle 6 are connected with the cavity wall of the gear cavity 4 in the two-stage oil-injected screw compressor of the embodiment, the top and bottom of the inter-stage baffle 6 are not connected with the cavity wall of the gear cavity 4, that is, a gap is also arranged between the bottom of the inter-stage baffle 6 and the bottom of the gear cavity 4, the gap between the bottom of the inter-stage baffle 6 and the bottom of the gear cavity 4 is the oil return passage for communicating the inter-stage passage 5 and the gear cavity 4, and the lubricating oil collected at the bottom of the gear cavity 4 flows into the inter-stage passage 5 through the oil return passage.

[0041] The above is only a specific embodiment of the application, and is not used to limit the implementation range of the application; if the application is modified or replaced without departing from the spirit and scope of the application, all should be covered in the protection scope of the claims of the application.

Claims

1. A two-stage oil-injected screw compressor, comprising a primary compressor, a secondary compressor, a gearbox, and an interstage structure, wherein the primary and secondary compressors are both connected to the gearbox and located on the same side of the gearbox, the interstage structure connects the exhaust end of the primary compressor and the intake end of the secondary compressor, and a primary oil injection port is provided in the compression chamber of the primary compressor; characterized in that, An interstage baffle is provided between the interstage structure and the gearbox. The left and right sidewalls and bottom of the interstage baffle are connected to the inner wall of the gearbox. A gap is provided between the top of the interstage baffle and the inner top surface of the gearbox. A lubricating oil and gas channel is provided between the interstage baffle and the inner top surface of the gearbox, and the lubricating oil and gas channel includes the gap. The interstage structure and the upper part of the gearbox are connected through the lubricating oil and gas channel. An oil return hole is provided at the lower part of the interstage baffle, and the interstage structure and the lower part of the gearbox are connected through the oil return hole.

2. The two-stage oil-injected screw compressor according to claim 1, characterized in that, The interstage structure is provided with at least one interstage oil injection port, which is used to inject cooling lubricating oil into the interstage structure.

3. The two-stage oil-injected screw compressor according to claim 2, characterized in that, The interstage oil injection ports are all located within the lubricating oil gas passage.

4. The two-stage oil-injected screw compressor according to claim 3, characterized in that, The interstage fuel injector is located on the inner wall of the interstage structure.

5. The two-stage oil-injected screw compressor according to claim 3, characterized in that, A cooling oil passage is provided above the interstage baffle, and the cooling oil passage extends into the lubricating oil gas passage. The interstage oil spray nozzles are all located on the wall of the cooling oil passage.

Images