Double-screw compressor unit

Abstract

The invention relates to the technical field of compressor cooling units, in particular to a double-screw compressor unit. The air inlet temperature and the air inlet pressure of a gaseous refrigerant can be increased, the limit temperature difference value in the screw compressor is reduced, and the temperature balance in the screw compressor and the compression efficiency of the gaseous refrigerant are improved; comprising a first unit and an evaporator, and the first unit comprises a screw compressor body, an oil-gas separator, a condenser and a throttling depressurization assembly which are sequentially connected; the first unit further comprises a gas return pipeline, a temperature increasing and pressurizing device, an oil gas pipeline and an oil return assembly. The screw compressor body comprises a shell, a male screw rotationally mounted in the shell, a female screw rotationally mounted in the shell and meshed with the male screw, and a driving motor for providing power for rotation of the male screw, and a hollow cavity is formed in the female screw; and the warming and pressurizing device is used for warming and pressurizing the low-temperature and low-pressure gaseous refrigerant refluxed at the evaporator.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor cooling units, in particular to a twin-screw compressor unit. Background Art

[0002] As we all know, screw compressors are composed of a pair of parallel, intermeshing male and female screws. They are the most widely used type of rotary compressor. They are divided into single-screw and twin-screw types. The screw compressors usually refer to twin-screw compressors. Screw compressors are an important part of refrigeration units.

[0003] For example, Chinese utility model patent CN217274923U discloses a dual-compressor water-cooled screw chiller, comprising a screw compressor assembly, an evaporator assembly, a condenser assembly, a refrigerant pipeline, and a water piping system. The evaporator and condenser assemblies are connected to the screw compressor assembly via refrigerant piping, the evaporator assembly is connected to the condenser assembly, and the water piping system is connected to the evaporator and condenser assemblies. Compared with traditional technologies, this system achieves automatic circulation cooling, is convenient and efficient, and is energy-efficient and low-consumption.

[0004] However, the following defects were found: the gaseous refrigerant entering the screw compressor is in a low-temperature and low-pressure state. After the female and male screws in the screw compressor have been working for a long time, the internal temperature of the screw compressor increases due to friction and the compression work of the gaseous refrigerant. The temperature difference between the gaseous refrigerant and the inside of the screw compressor is large (the temperature difference is greater than 100°C). The entry of low-temperature refrigerant causes uneven temperatures near the air inlet and outlet of the screw compressor. The female and male screws near the air inlet and outlet are slightly deformed due to uneven heating, which accelerates the wear of the female and male screws and affects the meshing degree of the female and male screws. The low intake pressure of the gaseous refrigerant entering the screw compressor causes a decrease in the density of the gaseous refrigerant, which in turn affects the suction volume of the screw compressor, resulting in a reduction in the actual exhaust volume of the compressor, thereby affecting the compression efficiency and affecting the compression efficiency of the screw compressor for the gaseous refrigerant. Summary of the Invention

[0005] In response to the deficiencies of the prior art, the present invention provides a twin-screw compressor unit that can increase the inlet temperature and pressure of the gaseous refrigerant, reduce the internal temperature difference of the screw compressor, improve the internal temperature balance of the screw compressor and the compression efficiency of the gaseous refrigerant.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solution: a twin-screw compressor unit, comprising a first unit and an evaporator, wherein the first unit comprises a screw compressor body, an oil-gas separator, a condenser, and a throttling and pressure reduction assembly connected in sequence; the first unit also comprises a return air pipeline, a heating and supercharging device, an oil-gas pipeline, and an oil return assembly; The screw compressor body includes a shell, a male screw rotatably installed in the shell, a female screw rotatably installed in the shell and meshing with the male screw, and a drive motor that provides power for the rotation of the male screw. A hollow cavity is provided inside the female screw. One end of the return air pipeline is connected to the air outlet on the evaporator, and the other end of the return air pipeline is connected to the air inlet end of the warming supercharger. The air outlet end of the warming supercharger is connected to the air inlet on the shell, and one end of the oil and gas pipeline is connected to the air outlet on the shell. The other end of the oil and gas pipeline is connected to the air inlet on the oil and gas separator. The oil return assembly includes an oil return pump and an oil return pipeline. The input end of the oil return pump extends into the bottom of the oil and gas separator, and the output end of the oil return pump is connected to the input end of the oil return pipeline. The output end of the oil return pipeline extends from the upper part of the shell into the shell; the warming booster is used to heat and pressurize the low-temperature and low-pressure gaseous refrigerant refluxed from the evaporator; further, the warming booster can use an electric auxiliary heating vacuum pump for pressurization and heating.

[0007] Preferably, the temperature increasing and supercharger includes a mounting shell, an air intake cylinder fixedly mounted on the mounting shell, an air outlet cylinder fixedly mounted on the mounting shell and arranged vertically offset with the air intake cylinder, a connecting pipe with both ends communicating with the interior of the air intake cylinder and the air outlet cylinder respectively, a first piston slidably mounted in the air intake cylinder, a second piston slidably mounted in the air outlet cylinder, and a driving member for driving the first piston and the second piston to slide.

[0008] The air intake cylinder is provided with an air intake pipe connected to the interior of the air intake cylinder, and a first one-way valve is installed in the air intake pipe to allow gas to enter the air intake cylinder in one direction. The output end of the return air pipeline is connected to the input end of the air intake pipe, and a second one-way valve is provided at the connection between the connecting pipe and the air outlet cylinder to allow gas in the connecting pipe to enter the air outlet cylinder in one direction. The air outlet cylinder is provided with an air outlet pipe connected to the air intake end of the shell; the driving member can adopt two driving cylinders, the two driving cylinders are fixedly installed in the mounting shell, and the first piston and the second piston are driven respectively by the two driving cylinders.

[0009] Preferably, a drive shaft is rotatably mounted on the mounting shell, and the driving member includes a first eccentric cam fixedly connected to the driving shaft, a first connecting shaft fixedly mounted on the first eccentric cam and away from the central axis of the driving shaft, a second eccentric cam rotatably mounted on the inner wall of the mounting shell, a second connecting shaft fixedly mounted on the second eccentric cam and away from the central axis of the driving shaft, a right-angle connecting plate, a first driving handle and a second driving handle, the first eccentric cam and the second eccentric cam are vertically arranged, the first connecting shaft and the second connecting shaft are fixedly connected by the right-angle connecting plate, one end of the first driving handle is rotatably connected to the first connecting shaft, the other end of the first driving handle is rotatably connected to the second piston, one end of the second driving handle is rotatably connected to the second connecting shaft, the other end of the second driving handle is rotatably connected to the first piston, and the driving shaft is transmission-connected to the male screw; further, the driving shaft is fixedly connected to the male screw.

[0010] Preferably, a bypass pipe is further included, a Venturi jet tube is installed on the oil return pipeline, an annular cavity is provided on the Venturi jet tube, a plurality of air inlet holes communicating with the annular cavity are provided at the neck of the Venturi jet tube, one end of the bypass pipe is communicated with the air outlet pipe, and the other end of the bypass pipe is communicated with the annular cavity.

[0011] Furthermore, the flow rate of the gas in the bypass pipe is less than 1 / 10 of the total flow rate of the gas in the outlet pipe.

[0012] Preferably, a heat dissipation fan is installed at the condenser, an air duct and a blocking plate are installed at the outflow end of the heat dissipation fan, and a flexible plastic tube extending toward the evaporator is installed at the end of the air duct.

[0013] Furthermore, the blocking plate can be slidably installed on the outflow end of the heat dissipation fan. The flexible plastic tube is preferably a plastic corrugated tube, and other flexible tubes with plasticity can also be used; the heat dissipation fan is preferably a volute fan.

[0014] Preferably, it further comprises a second unit having the same structure as the first unit; the first unit and the second unit serve as backup for each other.

[0015] Preferably, an airflow pipe is installed between the oil-gas separator and the condenser on the first unit and the second unit, a first electrically controlled valve is installed on the airflow pipe, and a communication pipe is installed between the two airflow pipes, a second electrically controlled valve is installed on the communication pipe.

[0016] Compared with the prior art, the present invention provides a twin-screw compressor unit with the following beneficial effects: In this twin-screw compressor unit, the gaseous refrigerant after being vaporized and absorbing heat in the evaporator enters the hollow cavity in the female screw through the return air pipeline. The temperature of the female screw is high after working for a long time, and the low-temperature gaseous refrigerant absorbs heat when passing through the female screw, thereby increasing the temperature of the gaseous refrigerant. As the temperature at the female screw decreases, the maximum high temperature value inside the screw compressor body decreases. After the gaseous refrigerant passes through the warming booster and does work, the temperature and pressure of the gaseous refrigerant are further increased, thereby increasing the inlet pressure and inlet temperature of the gaseous refrigerant entering the screw compressor body, reducing the internal maximum temperature difference of the screw compressor, and increasing the inlet pressure and density of the gaseous refrigerant entering the screw compressor body, which can effectively improve the temperature balance inside the screw compressor body and the compression efficiency of the gaseous refrigerant; the female and male screws are heated evenly, effectively reducing the wear rate of both. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention.

[0018] Figure 2 It is a schematic diagram of the top plan structure of the present invention.

[0019] Figure 3 It is a front view planar structural schematic diagram of the present invention.

[0020] Figure 4 The present invention Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle.

[0021] Figure 5 It is a schematic diagram of the internal three-dimensional structure of the temperature-increasing supercharger of the present invention.

[0022] Figure 6 It is a schematic diagram of the three-dimensional structure of the driving member of the present invention.

[0023] Figure 7 It is a schematic diagram of the internal cross-section of the venturi jet tube of the present invention.

[0024] Figure 8 The present invention Figure 1 Schematic diagram of the locally enlarged structure at point B in the middle.

[0025] Reference numerals in the accompanying drawings: 1. evaporator; 2. oil-gas separator; 3. condenser; 4. throttling and pressure-reducing assembly; 5. return air pipeline; 6. oil-gas pipeline; 7. housing; 8. male screw; 9. female screw; 10. drive motor; 11. oil return pump; 12. oil return pipeline; 13. mounting housing; 14. air inlet cylinder; 15. air outlet cylinder; 16. connecting pipeline; 17. first piston; 18. second piston; 19. air inlet pipe; 20. first one-way valve; 21. second one-way valve; 22. air outlet pipe; 23. drive shaft; 24. First eccentric cam; 25. First connecting shaft; 26. Second eccentric cam; 27. Second connecting shaft; 28. Right-angle connecting plate; 29. ​​First driving handle; 30. Second driving handle; 31. Bypass pipe; 32. Venturi jet tube; 33. Annular cavity; 34. Air inlet; 35. Cooling fan; 36. Air duct; 37. Sealing plate; 38. Flexible plastic tube; 39. First unit; 40. Air flow tube; 41. First electric control valve; 42. Series pipe; 43. Second electric control valve; 44. Second unit. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions therein may be combined with each other.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0029] Example 1 Please refer to Figure 1-4 A twin-screw compressor unit includes a first unit 39, a second unit 44, and an evaporator 1. The first unit 39 is connected to the air outlet of the evaporator 1. The first unit 39 and the second unit 44 have the same structure and serve as backup for each other. The first unit 39 and the second unit 44 are switched by necessary switching valves, etc., which will not be further described here.

[0030] The following description will be made by taking the first unit 39 as an example. The first unit 39 includes a screw compressor body, an oil-gas separator 2, a condenser 3 and a throttling and pressure reduction assembly 4 connected in sequence; the first unit 39 also includes a return air pipeline 5, a warming and supercharging device, an oil-gas pipeline 6 and an oil return assembly. The screw compressor body includes a shell 7, a male screw 8 rotatably installed in the shell 7, a female screw 9 rotatably installed in the shell 7 and meshing with the male screw 8, and a drive motor 10 that provides power for the rotation of the male screw 8. A hollow cavity is provided inside the female screw 9. One end of the return air pipeline 5 is connected to the air outlet end on the evaporator 1, and the other end of the return air pipeline 5 is connected to the air inlet end of the warming and supercharging device. The air outlet end of the warming and supercharging device is connected to the air inlet on the shell 7. One end of the oil-gas pipeline 6 is connected to the air outlet on the shell 7. The oil The other end of the air pipe 6 is connected to the air inlet on the oil-gas separator 2. The oil return assembly includes an oil return pump 11 and an oil return pipe 12. The input end of the oil return pump 11 extends to the bottom of the oil-gas separator 2, and the output end of the oil return pump 11 is connected to the input end of the oil return pipe 12. The output end of the oil return pipe 12 extends from the upper part of the shell 7 into the shell 7; the warming booster is used to heat and pressurize the low-temperature and low-pressure gaseous refrigerant refluxed from the evaporator 1; further, the warming booster can use an electric auxiliary heating vacuum pump for pressurization and heating.

[0031] An airflow pipe 40 is installed between the oil-gas separator 2 and the condenser 3 on the first unit 39 and the second unit 44 , and a first electrically controlled valve 41 is installed on the airflow pipe 40 . A connecting pipe 42 is installed between the two airflow pipes 40 , and a second electrically controlled valve 43 is installed on the connecting pipe 42 .

[0032] The first unit 39 and the second unit 44 serve as backup for each other. When one of the units fails, the other unit can be started to avoid shutdown of the twin-screw compressor unit, effectively reducing the accident rate of the evaporator 1 not cooling due to shutdown; when the ambient temperature is high or the environment needs to be cooled quickly, the second electrically controlled valve 43 on the series pipe 42 can be opened, and the first electrically controlled valve 41 on the first unit 39 or the second unit 44 can be opened to allow the pressurized gaseous refrigerant to enter the same condenser 3, that is, to realize the parallel use of two groups of screw compressor bodies, further improve the liquefaction efficiency of the gaseous refrigerant in the condenser 3, accelerate the circulation of the refrigerant in the entire system, so as to achieve rapid cooling of the environment and improve the applicability of the twin-screw compressor unit to different working conditions; it should be noted that during the adjustment process, the refrigerant flow and pressure passing through the throttling and pressure reducing component 4 should be adaptively adjusted.

[0033] In the twin-screw compressor unit provided by the present embodiment, the driving motor 10 drives the male screw 8 to rotate, and the male screw 8 drives the driving shaft 23 and the driving member to rotate synchronously. After being driven by the second eccentric cam 26, the second connecting shaft 27 and the second driving handle 30, the first piston 17 moves downward along the inner wall of the air inlet cylinder 14. After being driven by the first eccentric cam 24, the first connecting shaft 25 and the first driving handle 29, the second piston 18 is fed along the inner wall of the air outlet cylinder 15 toward the side away from the mounting shell 13. At this time, the air pressure in the air inlet cylinder 14 and the connecting pipe 16 decreases, and the pressure in the air outlet cylinder 15 increases. The first one-way valve 20 opens, the second one-way valve 21 closes, and the gaseous refrigerant is sucked into the In the air intake cylinder 14; as the drive shaft 23 rotates, after being driven by the second eccentric cam 26, the second connecting shaft 27 and the second driving handle 30, the first piston 17 moves up along the inner wall of the air intake cylinder 14, and after being driven by the first eccentric cam 24, the first connecting shaft 25 and the first driving handle 29, the second piston 18 feeds along the inner wall of the air outlet cylinder 15 toward the side close to the mounting shell 13. At this time, the air pressure in the air intake cylinder 14 and the connecting pipe 16 increases, and the pressure in the air outlet cylinder 15 decreases, the first one-way valve 20 is closed, and the second one-way valve 21 is opened. The gaseous refrigerant is pressed into the air outlet cylinder 15 through the connecting pipe 16 and discharged through the air outlet pipe 22. This reciprocating process realizes continuous pressurization and work on the gaseous refrigerant.

[0034] The reflux speed of the gaseous refrigerant in the return air pipe 5 to the warming and boosting device can be increased, and the gaseous refrigerant after absorbing heat can be avoided from accumulating in the condenser 3, thereby ensuring that the condenser 3 is in a low-pressure state, which is conducive to the vaporization of the liquid refrigerant in the condenser 3 and improving the refrigeration effect of the condenser 3; the gaseous refrigerant is compressed in the air inlet tube 14 and the connecting pipe 16, and is compressed in the air outlet tube 15. Under the continuous pressurization, the volume of the gaseous refrigerant decreases, and the density and temperature increase; the gaseous refrigerant is continuously compressed in three stages by the screw compressor body and the warming and boosting device; the warming and boosting device and the screw compressor body are started and stopped synchronously, and continuous three-stage compression of the gaseous refrigerant can be achieved without the need for external drive to do additional work, which can greatly improve the compression efficiency of the gaseous refrigerant, effectively shorten the liquefaction time of the gaseous refrigerant in the condenser 3, and significantly enhance the efficiency of the entire first unit 39.

[0035] Please refer to Figure 5The temperature increasing supercharger includes a mounting shell 13, an air inlet cylinder 14 fixedly mounted on the mounting shell 13, an air outlet cylinder 15 fixedly mounted on the mounting shell 13 and arranged vertically offset with the air inlet cylinder 14, a connecting pipe 16 with both ends communicating with the interior of the air inlet cylinder 14 and the air outlet cylinder 15, a first piston 17 slidably mounted in the air inlet cylinder 14, a second piston 18 slidably mounted in the air outlet cylinder 15, and a driving member for driving the first piston 17 and the second piston 18 to slide. The air inlet cylinder 14 is provided with an air inlet pipe 19 communicating with the interior of the air inlet cylinder 14. A first one-way valve 20 is installed in the air intake pipe 19, which allows gas to enter the air intake cylinder 14 in one direction. The output end of the return air pipeline 5 is connected to the input end of the air intake pipe 19. A second one-way valve 21 is provided at the connection between the connecting pipe 16 and the air outlet cylinder 15, which allows the gas in the connecting pipe 16 to enter the air outlet cylinder 15 in one direction. The air outlet cylinder 15 is provided with an air outlet pipe 22 connected to the air intake end of the shell 7; the driving member can adopt two driving cylinders, the two driving cylinders are fixedly installed in the mounting shell 13, and the first piston 17 and the second piston 18 are driven respectively by the two driving cylinders.

[0036] Please refer to Figure 6 The drive shaft 23 is rotatably mounted on the mounting shell 13, and the driving member includes a first eccentric cam 24 fixedly connected to the drive shaft 23, a first connecting shaft 25 fixedly mounted on the first eccentric cam 24 and away from the central axis of the drive shaft 23, a second eccentric cam 26 rotatably mounted on the inner wall of the mounting shell 13, a second connecting shaft 27 fixedly mounted on the second eccentric cam 26 and away from the central axis of the drive shaft 23, a right-angle connecting plate 28, a first driving handle 29 and a second driving handle 30. The first eccentric cam 24 and the second eccentric cam 26 are arranged vertically, the first connecting shaft 25 and the second connecting shaft 27 are fixedly connected by the right-angle connecting plate 28, one end of the first driving handle 29 is rotatably connected to the first connecting shaft 25, and the other end of the first driving handle 29 is rotatably connected to the second piston 18, one end of the second driving handle 30 is rotatably connected to the second connecting shaft 27, and the other end of the second driving handle 30 is rotatably connected to the first piston 17, and the drive shaft 23 is transmission-connected to the male screw 8; further, the drive shaft 23 is fixedly connected to the male screw 8.

[0037] Example 2 The twin-screw compressor unit provided in Example 1 is further optimized, specifically, as Figure 7-8As shown, it also includes a bypass pipe 31, a Venturi jet tube 32 is installed on the return oil pipeline 12, an annular cavity 33 is provided on the Venturi jet tube 32, and a plurality of air inlet holes 34 communicating with the annular cavity 33 are provided at the neck of the Venturi jet tube 32. One end of the bypass pipe 31 is communicated with the outlet pipe 22, and the other end of the bypass pipe 31 is communicated with the annular cavity 33; further, the flow rate of the gas in the bypass pipe 31 is less than 1 / 10 of the total flow rate of the gas in the outlet pipe 22; to ensure that the air intake of the screw compressor body is sufficient; more specifically, a flow valve is installed at the bypass pipe 31 to adaptively adjust the flow rate of the gaseous refrigerant flowing through the bypass pipe 31.

[0038] In the twin-screw compressor unit provided by this embodiment, part of the gaseous refrigerant treated by the warming and supercharger enters the annular cavity 33 in the venturi jet tube 32 through the bypass pipe 31. When the cooling lubricating oil flows through the neck of the venturi jet tube 32, the pressure at the air inlet is reduced, and the gaseous refrigerant enters the venturi jet tube 32 through each air inlet hole 34 and contacts the high-temperature cooling lubricating oil. Because the temperature of the gaseous refrigerant is much lower than that of the cooling lubricating oil, the cooling lubricating oil is cooled by the low-temperature gaseous refrigerant, thereby reducing the oil temperature of the cooling lubricating oil entering the screw compressor body. The cooling lubricating oil, which becomes mist due to the air pressure difference, is sprayed into the compression chamber of the screw compressor body, thereby achieving the functions of compressing the gaseous refrigerant, reducing the temperature in the compression chamber, and sealing and lubricating the female and male screws, effectively reducing the extreme high temperature value in the screw compressor body, reducing the temperature difference change rate of the screw compressor body, and playing a positive effect on reducing the wear rate of the female and male screws.

[0039] Example 3 The twin-screw compressor unit provided in Example 2 is further optimized, specifically, as Figure 1-3 As shown, a heat dissipation fan 35 is installed at the condenser 3, and an air duct 36 and a blocking plug 37 are installed at the outflow end of the heat dissipation fan 35. A flexible plastic tube 38 extending toward the evaporator 1 is installed at the end of the air duct 36; further, the blocking plug 37 can be slidably installed on the outflow end of the heat dissipation fan 35, and the flexible plastic tube 38 is preferably a plastic corrugated tube, and other flexible tubes with plasticity can also be used; the heat dissipation fan 35 is preferably a volute fan.

[0040] The twin-screw compressor unit provided in this embodiment can accelerate the dissipation of heat in the condenser 3 through the heat dissipation fan 35; when the unit has been used for a period of time, ice will appear on the outer wall of the evaporator 1 due to the low temperature, and manual ice removal is relatively laborious; the unit can be shut down, the sealing plug plate 37 can be used to block the outflow end of the heat dissipation fan 35, and the heat dissipation fan 35 can be started. The heat dissipation fan 35 will transport the residual heat from the condenser 3 to the evaporator 1 through the induced draft pipe 36 and the flexible plastic tube 38. By moving the outflow port position of the flexible plastic tube 38, the ice in various parts of the evaporator 1 can be comprehensively processed. The ice on the evaporator 1 is quickly dissolved under the action of the high-temperature airflow. While cooling the condenser 3, the residual heat from the condenser 3 is used to clean the ice on the evaporator 1, which is more energy-saving and environmentally friendly, and effectively improves the efficiency and effect of ice cleaning at the evaporator 1.

[0041] The use process of the twin-screw compressor unit provided by the present invention is as follows: the evaporator 1 is installed in the environment to be cooled, and the gaseous refrigerant after the secondary heating and pressurization is compressed by the screw compressor body to increase the temperature and pressure of the gaseous refrigerant. Under the action of continuous pressurization, the cooling lubricating oil and the gaseous refrigerant enter the oil-gas separator 2 together, and the oil and gas are separated by the oil-gas separator 2. The return oil pump 11 re-injects the cooling lubricating oil in the oil-gas separator 2 into the shell 7 of the screw compressor body through the return oil pipeline 12, and the high-temperature and high-pressure refrigerant enters the condenser 3. As the pressure in the condenser 3 gradually increases, the gaseous refrigerant is converted into liquid refrigerant and releases a large amount of heat. The liquid refrigerant enters the evaporator 1 after the flow and pressure are adjusted by the throttling and pressure reducing component 4. At this time, the pressure in the evaporator 1 is low, and the liquid refrigerant quickly vaporizes and absorbs heat to form a low-temperature and low-pressure gaseous refrigerant, which cools the environment through the evaporator 1. The low-temperature and low-pressure gaseous refrigerant passes through the return air pipeline 5, the hollow cavity inside the screw and the warming supercharger and then flows back to the shell 7 on the screw compressor body; in this way, the twin-screw compressor unit achieves cooling of the environment.

[0042] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

Claims

1. A twin-screw compressor unit, characterized in that: The invention comprises a first machine unit (39) and an evaporator (1), wherein the first machine unit (39) comprises a screw compressor body, an oil-gas separator (2), a condenser (3) and a throttling and pressure reduction assembly (4) which are connected in sequence; the first machine unit (39) further comprises a return air pipeline (5), a temperature increasing and pressure increasing device, an oil-gas pipeline (6) and an oil return assembly; The screw compressor body comprises a shell (7), a male screw (8) rotatably mounted in the shell (7), a female screw (9) rotatably mounted in the shell (7) and meshing with the male screw (8), and a driving motor (10) for providing power for the rotation of the male screw (8); a hollow cavity is provided inside the female screw (9); one end of the return air pipeline (5) is connected to the air outlet end of the evaporator (1); the other end of the return air pipeline (5) is connected to the air inlet end of the warming supercharger; the air outlet end of the warming supercharger is connected to the air inlet port of the shell (7); one end of the oil-gas pipeline (6) is connected to the air outlet port of the shell (7); the other end of the oil-gas pipeline (6) is connected to the air inlet port of the oil-gas separator (2); The oil return assembly comprises an oil return pump (11) and an oil return pipeline (12); the input end of the oil return pump (11) extends into the bottom of the oil-gas separator (2); the output end of the oil return pump (11) is connected to the input end of the oil return pipeline (12); the output end of the oil return pipeline (12) extends from the upper part of the shell (7) into the shell (7); the temperature increase and pressure increaser is used to increase the temperature and pressure of the low-temperature and low-pressure gaseous refrigerant returning from the evaporator (1).

2. A twin-screw compressor unit according to claim 1, characterized in that: The temperature increasing supercharger comprises a mounting shell (13), an air inlet cylinder (14) fixedly mounted on the mounting shell (13), an air outlet cylinder (15) fixedly mounted on the mounting shell (13) and arranged vertically offset with the air inlet cylinder (14), a connecting pipe (16) with two ends respectively communicating with the inside of the air inlet cylinder (14) and the air outlet cylinder (15), a first piston (17) slidably mounted in the air inlet cylinder (14), a second piston (18) slidably mounted in the air outlet cylinder (15), and a driving member for driving the first piston (17) and the second piston (18) to slide, wherein the air inlet cylinder (14) is provided with a first piston (17) and a second piston (18) to slide. The cylinder (14) is provided with an air intake pipe (19) which is connected to the interior of the air intake cylinder (14); a first one-way valve (20) is installed in the air intake pipe (19) for allowing gas to enter the air intake cylinder (14) in one direction; the output end of the return air pipeline (5) is connected to the input end of the air intake pipe (19); a second one-way valve (21) is provided at the connection point between the connecting pipe (16) and the air outlet cylinder (15) for allowing gas in the connecting pipe (16) to enter the air outlet cylinder (15) in one direction; and an air outlet pipe (22) which is connected to the air intake end of the shell (7) is provided at the air outlet cylinder (15).

3. A twin-screw compressor unit according to claim 2, characterized in that: A drive shaft (23) is rotatably mounted on the mounting shell (13), and the drive member comprises a first eccentric cam (24) fixedly connected to the drive shaft (23), a first connecting shaft (25) fixedly mounted on the first eccentric cam (24) and away from the central axis of the drive shaft (23), a second eccentric cam (26) rotatably mounted on the inner wall of the mounting shell (13), a second connecting shaft (27) fixedly mounted on the second eccentric cam (26) and away from the central axis of the drive shaft (23), a right-angle connecting plate (28), a first drive handle (29), and a second drive handle ( 30), the first eccentric cam (24) and the second eccentric cam (26) are arranged vertically, the first connecting shaft (25) and the second connecting shaft (27) are fixedly connected via a right-angle connecting plate (28), one end of the first driving handle (29) is rotatably connected to the first connecting shaft (25), the other end of the first driving handle (29) is rotatably connected to the second piston (18), one end of the second driving handle (30) is rotatably connected to the second connecting shaft (27), the other end of the second driving handle (30) is rotatably connected to the first piston (17), and the driving shaft (23) is drivingly connected to the male screw (8).

4. A twin-screw compressor unit according to claim 1, characterized in that: It also comprises a bypass pipe (31), a Venturi jet pipe (32) being installed on the oil return pipeline (12), an annular cavity (33) being provided on the Venturi jet pipe (32), a plurality of air inlet holes (34) being provided at the neck of the Venturi jet pipe (32) and being communicated with the annular cavity (33), one end of the bypass pipe (31) being communicated with the air outlet pipe (22), and the other end of the bypass pipe (31) being communicated with the annular cavity (33).

5. A twin-screw compressor unit according to claim 1, characterized in that: The condenser (3) is provided with a heat dissipation fan (35), an air induction pipe (36) and a blocking plug plate (37) are provided at the outlet end of the heat dissipation fan (35), and a flexible plastic tube (38) extending towards the evaporator (1) is provided at the end of the air induction pipe (36).

6. A twin-screw compressor unit according to claim 1, characterized in that: It also includes a second unit (44) having the same structure as the first unit (39); the first unit (39) and the second unit (44) serve as backup for each other.

7. A twin-screw compressor unit according to claim 6, characterized in that: An airflow pipe (40) is installed between the oil-gas separator (2) and the condenser (3) on the first unit (39) and the second unit (44), a first electrically controlled valve (41) is installed on the airflow pipe (40), a series connection pipe (42) is installed between the two airflow pipes (40), and a second electrically controlled valve (43) is installed on the series connection pipe (42).

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