High-efficiency screw-type dry vacuum pump structure

Abstract

The invention provides a high-efficiency screw-type dry vacuum pump structure, and relates to the technical field of vacuum pumps, the high-efficiency screw-type dry vacuum pump structure comprises a pump body with a cavity and two variable-pitch screws, the two sides of the pump body are provided with an air inlet end and an air outlet end respectively, and the two ends of the two variable-pitch screws are rotatably installed on the two sides in the pump body through sealing pieces; a cooling circulation device is further arranged on the outer side wall of the pump body, the output end of the cooling circulation device makes contact with the surface of the sealing piece, one end of the pump body is provided with a driving mechanism used for driving the two variable-pitch screws to synchronously rotate in different directions, the sealing piece comprises a sealing sleeve, a bearing sleeve and a check ring, the sealing sleeve is fixedly installed at the end of the pump body, and an inflation bag is embedded in the sealing sleeve. According to the variable-pitch screw, the sine spiral line design of the variable-pitch screw is adopted, so that gas turbulence can be reduced, the thickness of the spiral blade is gradually changed to form progressive compression, and the gas leakage rate is further reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum pumps, and particularly to a high-efficiency screw-type dry vacuum pump structure. Background Art

[0002] In industries such as chemical engineering, petroleum, light industry, medicine, and food, processes such as vacuum filtration, vacuum feeding, vacuum concentration, and vacuum degassing are required; for the above processes, a liquid ring vacuum pump is often used as the front-stage pump of a vacuum unit or a single pump for vacuum pumping. Although the liquid ring vacuum pump has a simple structure and uniform air intake, there is no medium in the working chamber of the dry screw vacuum pump, and a clean vacuum can be obtained; the recovery rate of process gases is high, the tail gas treatment is convenient, and at the same time, the emissions of oil gas and oil fume are avoided, and the environmental pollution is small. Therefore, people may think of using a dry screw vacuum pump to replace the liquid ring vacuum pump. The dry screw vacuum pump is a gas pumping device that uses a pair of screws to rotate synchronously and at high speed in the opposite direction in the pump housing to generate the suction and exhaust effects; the screw vacuum pump can pump gas containing a large amount of water vapor and a small amount of dust, so it is widely used in enterprise fields with high requirements for clean vacuum, such as pharmaceutical, chemical, semiconductor, and food industries.

[0003] Its core structure usually includes the following parts: pump body and screw assembly: the pump body is a hollow cavity, and a pair of parallel screws (rotors) are installed inside. The screw surface is processed with spiral grooves (helices). The screws are driven to rotate in the opposite direction through synchronous gears or belts, and the volume change of the screw grooves is used to realize the inhalation, compression, and discharge of gas; sealing and bearing system: both ends of the screws are connected to the pump body through mechanical seals or oil seals to prevent gas leakage; the bearings support the rotation of the screws, and usually metal bearings or oil-containing bearings are used; drive mechanism: driven by a motor, and the power is transmitted to the screws through a coupling or a gear set; cooling system: traditional designs mostly use air cooling or simple water cooling, and the heat of the pump body and bearings is removed through heat sinks or circulating water.

[0004] However, traditional screws use a fixed pitch (the distance between the helices remains unchanged), and the helices are mostly straight lines or simple curves. Gas is likely to flow back at the screw gaps, and the leakage rate is relatively high, resulting in a short residence time of the gas in the pump cavity and an insufficient compression process.

[0005] Therefore, it is necessary to provide a new high-efficiency screw-type dry vacuum pump structure to solve the above technical problems. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a high-efficiency screw-type dry vacuum pump structure. The structure of the high-efficiency screw-type dry vacuum pump provided by the present invention includes a pump body with a cavity and two variable pitch screws. An air inlet end and an air outlet end are respectively arranged on both sides of the pump body. Both ends of the two variable pitch screws are rotatably installed on both sides inside the pump body through seals. A cooling circulation device is also arranged on the outer wall of the pump body. The output end of the cooling circulation device is in contact with the surface of the seal. A driving mechanism is arranged at one end of the pump body for driving the two variable pitch screws to rotate synchronously and in opposite directions. The seal includes a sealing sleeve, a bearing sleeve and a retaining ring. The sealing sleeve is fixedly installed at the end of the pump body. An air-filled balloon is embedded inside the sealing sleeve. The bearing sleeve is sleeved on one end of the variable pitch screw and is fixedly installed inside the sealing sleeve. The retaining ring is fixedly installed on the outside of the sealing sleeve through a plurality of screws.

[0007] Further, the cooling circulation device includes a water cooling component, a cooling shunt pipe and a cooling return pipe. The water cooling component is fixedly installed on the outside of the pump body. Cooling pipes are fixed at both ends of the cooling shunt pipe and the cooling return pipe. Both of the two cooling pipes are in a "U" shape. The cooling return pipe is connected to the input end of the water cooling component, and the cooling shunt pipe is connected to the output end of the water cooling component. Both ends of the cooling pipe are respectively connected to the inner cavities of the cooling shunt pipe and the cooling return pipe, and the "U" shaped part of the cooling pipe is in fit with the surface of the sealing sleeve.

[0008] Further, the driving mechanism includes a reduction motor, a frame and two opposite spur gears. The frame is fixedly connected to one end of the pump body. The reduction motor is fixedly installed on the frame, and the rotor end of the reduction motor is connected to one end of the variable pitch screw through a coupling. The two spur gears are respectively fixedly installed on one end of the two variable pitch screws, and the two spur gears are meshed with each other.

[0009] Further, air inlet outer end covers and air outlet outer end covers are also arranged on both sides of the pump body. The air inlet outer end covers and the air outlet outer end covers are respectively hermetically connected to the edges of the pump body. An air inlet pipe is arranged at the top of the air inlet outer end cover, and the air inlet pipe is connected to the air inlet end of the pump body. An exhaust pipe is arranged on one side of the air outlet outer end cover, and the exhaust pipe is connected to the air outlet end of the pump body.

[0010] Further, the thickness of the spiral blades of the variable pitch screw gradually increases from one end to the other end.

[0011] Further, the spiral of the variable pitch screw is a sine spiral.

[0012] Further, the central angle of the spiral of the variable pitch screw is 150° - 210°.

[0013] Furthermore, the water cooling assembly includes a heat exchanger, a water cooling block, a water tank and a water pump. The input end of the heat exchanger is connected to the middle part of the cooling return pipe. The input end of the water cooling block is connected to the output end of the heat exchanger. The input end of the water tank is connected to the output end of the water cooling block. The output end of the water tank is connected to the input end of the water pump. The output end of the water pump is connected to the middle part of the cooling shunt pipe.

[0014] Furthermore, a first connecting pipe and a second connecting pipe are respectively communicated with the middle parts of the cooling shunt pipe and the cooling return pipe. One end of the first connecting pipe is connected to the input end of the heat exchanger. One end of the second connecting pipe is connected to the output end of the water pump.

[0015] Compared with the related art, the high-efficiency screw-type dry vacuum pump structure provided by the present invention has the following beneficial effects: 1. An air-filled bag is embedded inside the envelope of the present invention. The air-filled bag can be inflated or deflated to dynamically adjust the sealing pressure, prevent gas from leaking from the screw end, and use the air-filled bag for sealing without lubricating oil, avoiding oil pollution and being suitable for clean environments.

[0016] 2. The present invention adopts a variable pitch screw sinusoidal spiral design, which can reduce gas turbulence. The thickness of the spiral blade gradually changes to form a progressive compression, further reducing the gas leakage rate and improving the compression efficiency. At the same time, the U-shaped cooling pipe fits the envelope, is distributed to multiple "U" - shaped cooling pipes through the cooling shunt pipe and absorbs heat. The heat of the seal and the end of the pump body is absorbed. The cooled liquid returns to the heat exchanger through the cooling return pipe. After further cooling by the water cooling block of the semiconductor refrigeration sheet, it circulates to the water tank. The water cooling block of the semiconductor refrigeration sheet actively refrigerates to reduce the temperature of the high-temperature coolant to a set value, while the heat exchanger assists in heat dissipation to prevent heat accumulation in the system. Description of the Drawings

[0017] Figure 1 is the overall structural schematic diagram of the high-efficiency screw-type dry vacuum pump structure provided by the present invention; Figure 2 is the sectional structural schematic diagram of the high-efficiency screw-type dry vacuum pump structure provided by the present invention; Figure 3 is Figure 2 the enlarged structural schematic diagram of the position A shown in; Figure 4 is the internal structural schematic diagram of the pump body provided by the present invention; Figure 5 is the disassembled structural schematic diagram of the seal provided by the present invention; Figure 6 is the structural schematic diagram of the cooling circulation device provided by the present invention; Figure 7 Schematic structural diagram of the spur gear provided by the present invention.

[0018] Reference numerals in the figure: 1, pump body; 2, variable pitch screw; 3, sleeve; 4, bearing sleeve; 5, retaining ring; 6, inflatable bag; 7, cooling shunt pipe; 8, cooling return pipe; 9, cooling pipe; 10, reduction motor; 11, frame; 12, spur gear; 13, intake outer end cover; 14, exhaust outer end cover; 15, intake pipe; 16, exhaust pipe; 17, heat exchanger; 18, water-cooled block; 19, water tank; 20, water pump; 21, connecting pipe I; 22, connecting pipe II. Specific embodiments

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

[0021] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0022] In the specific implementation process, as Figures 1-7 shown, the high-efficiency screw-type dry vacuum pump structure includes a pump body 1 with a cavity and two variable pitch screws 2. Both sides of the pump body 1 are respectively provided with an intake end and an exhaust end. Both ends of the two variable pitch screws 2 are rotatably installed on both sides inside the pump body 1 through seals. One end of the pump body 1 is provided with a driving mechanism for driving the two variable pitch screws 2 to rotate synchronously and in opposite directions. The thickness of the spiral blades of the variable pitch screw 2 gradually increases from one end to the other end. The spiral line of the variable pitch screw 2 is a sine spiral line, and the central angle of the spiral line of the variable pitch screw 2 is 150° - 210°. Gas enters the cavity of the pump body 1 from the intake end and is "grabbed" by the spiral blades of the rotating variable pitch screw 2. In the compression stage, the two screws rotate in opposite directions through the meshing of the spur gear 12 to ensure that the spiral groove is always closed, avoiding gas short-circuit. The compressed high-pressure gas is discharged through the exhaust end. It should be noted that the central angle of the helix of the screw (150°-210°) prolongs the residence time of the gas in the pump cavity, improving the compression efficiency. The thickness of the spiral blade gradually thickens towards the end of the screw, forming a progressive compression, reducing gas reflux and leakage. The sine spiral design reduces friction and vibration during meshing, enhancing the operating stability; Reference Figure 3 and Figure 5 As shown, the seal includes a seal sleeve 3, a bearing sleeve 4 and a retaining ring 5. The seal sleeve 3 is fixedly installed at the end of the pump body 1. An air-filled bag 6 is embedded inside the seal sleeve 3. The bearing sleeve 4 is sleeved on one end of the variable pitch screw 2 and is fixedly installed inside the seal sleeve 3. The retaining ring 5 is fixedly installed on the outside of the seal sleeve 3 by a plurality of screws. The seal sleeve 3 is fixed to the end of the pump body 1 by screws. The internally embedded air-filled bag 6 (such as rubber or silica gel material) forms an initial sealing layer. The bearing sleeve 4 is sleeved on the end of the screw, providing rotational support and reducing friction and wear at the same time. The air-filled bag 6 can be inflated or deflated to adjust the sealing pressure in real time, preventing gas from leaking from the end of the screw. Using the air-filled bag 6 for sealing does not require lubricating oil, avoiding oil pollution and being suitable for clean environments.

[0023] It should be noted that, reference Figure 4 and Figure 7 As shown, the drive mechanism includes a reduction motor 10, a frame 11 and two opposite spur gears 12. The frame 11 is fixedly connected to one end of the pump body 1. The reduction motor 10 is fixedly installed on the frame 11, and the rotor end of the reduction motor 10 is connected to one end of the variable pitch screw 2 through a coupling. The two spur gears 12 are respectively fixedly installed on one end of the two variable pitch screws 2, and the two spur gears 12 are meshed with each other. The reduction motor 10 drives one end of the variable pitch screw 2 through the coupling. The spur gear 12 at the end of this variable pitch screw 2 meshes with the spur gear 12 of the other variable pitch screw 2, driving the other variable pitch screw 2 to rotate in the opposite direction. The meshing of the spur gears 12 ensures that the screw speeds are consistent, avoiding gas leakage caused by out-of-sync.

[0024] It should be further noted that an air inlet outer end cover 13 and an exhaust outer end cover 14 are also provided on both sides of the pump body 1. The air inlet outer end cover 13 and the exhaust outer end cover 14 are respectively hermetically connected to the edge of the pump body 1. An air inlet pipe 15 is provided at the top of the air inlet outer end cover 13, and the air inlet pipe 15 is connected to the air inlet end of the pump body 1. A discharge pipe 16 is provided on one side of the exhaust outer end cover 14, and the discharge pipe 16 is connected to the exhaust end of the pump body 1.

[0025] Embodiment 2 In a specific implementation process, following the same structure as Embodiment 1 and different from Embodiment 1, reference Figure 6As shown in the figure, a cooling circulation device is also provided on the outer side wall of the pump body 1. The output end of the cooling circulation device is in contact with the surface of the seal. The cooling circulation device includes a heat exchanger 17, a water-cooled block 18, a water tank 19, a water pump 20, a cooling shunt pipe 7 and a cooling return pipe 8. Cooling pipes 9 are fixed at both ends of the cooling shunt pipe 7 and the cooling return pipe 8. Both of the two cooling pipes 9 are in a "U" shape. The heat exchanger 17, the water-cooled block 18, the water tank 19 and the water pump 20 are all fixedly installed on the outer side of the pump body 1. Among them, the water-cooled block 18 is cooled by a thermoelectric cooler. The input end of the heat exchanger 17 is connected to the middle part of the cooling return pipe 8. The input end of the water-cooled block 18 is connected to the output end of the heat exchanger 17. The input end of the water tank 19 is connected to the output end of the water-cooled block 18. The output end of the water tank 19 is connected to the input end of the water pump 20. The output end of the water pump 20 is connected to the middle part of the cooling shunt pipe 7. Connecting pipes 21 and 22 are respectively communicated with the middle parts of the cooling shunt pipe 7 and the cooling return pipe 8. One end of the connecting pipe 21 is connected to the input end of the heat exchanger 17. One end of the connecting pipe 22 is connected to the output end of the water pump 20. The water pump 20 extracts the coolant from the water tank 19, distributes it to multiple "U"-shaped cooling pipes 9 through the cooling shunt pipe 7 for heat absorption. The cooled liquid returns to the heat exchanger 17 through the cooling return pipe 8. After being further cooled by the water-cooled block 18 of the thermoelectric cooler, it circulates to the water tank 19. The water-cooled block 18 of the thermoelectric cooler can actively refrigerate through the Peltier effect, reducing the temperature of the high-temperature coolant to the set value. The heat exchanger 17 assists in heat dissipation to prevent heat accumulation in the system; Both ends of the cooling pipe 9 are respectively connected to the inner cavities of the cooling shunt pipe 7 and the cooling return pipe 8. The "U"-shaped part of the cooling pipe 9 is attached to the surface of the seal sleeve 3. The cooling pipe 9 is attached to the surface of the seal sleeve 3 to absorb the heat between the seal and the end of the pump body 1.

[0026] The working principle provided by the present invention is as follows: When the device is in use, the reduction motor 10 drives the screw to rotate, and the spur gears 12 are engaged to ensure synchronous reverse rotation. The cooling system is started, the water pump 20 circulates the coolant, the thermoelectric cooler starts to cool down, the gas enters the pump body 1 from the intake pipe 15, and is discharged from the exhaust end after being compressed by the variable pitch screw 2; the inflatable bag 6 of the seal maintains dynamic sealing, the cooling system continuously takes away the heat at the end, the coolant circulation path ensures the temperature stability of each component, the cooling pipe 9 and the heat exchanger 17 are regularly cleaned to prevent scale blockage; check the elasticity of the inflatable bag 6 of the seal, and replace it if necessary.

[0027] The circuits and controls involved in the present invention are all prior arts and will not be elaborated here.

[0028] The foregoing has shown and described the basic principles, main features and advantages of the present invention. For a person skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes that fall within the meaning and scope of the equivalent elements of the claims in the present invention, and any reference signs in the claims should not be regarded as limiting the claims involved.

[0029] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. A person skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by a person skilled in the art.

Claims

1. A high-efficiency screw-type dry vacuum pump structure, characterized in that: The invention comprises a pump body (1) having a cavity and two variable pitch screws (2), wherein an air inlet end and an air outlet end are respectively arranged on both sides of the pump body (1), and both ends of the two variable pitch screws (2) are rotatably mounted on both sides of the inside of the pump body (1) through sealing members, and a cooling circulation device is also arranged on the outer wall of the pump body (1), and the output end of the cooling circulation device is in contact with the surface of the sealing member, and a driving mechanism for driving the two variable pitch screws (2) to rotate synchronously in opposite directions is arranged at one end of the pump body (1); The sealing component comprises a sleeve (3), a bearing sleeve (4) and a retaining ring (5); the sleeve (3) is fixedly mounted on the end of the pump body (1); an inflatable bag (6) is embedded in the sleeve (3); the bearing sleeve (4) is sleeved on one end of the variable pitch screw (2), and the bearing sleeve (4) is fixedly mounted in the sleeve (3); and the retaining ring (5) is fixedly mounted on the outside of the sleeve (3) by means of a plurality of screws.

2. The high-efficiency screw dry vacuum pump structure according to claim 1, characterized in that: The cooling circulation device comprises a water cooling component, a cooling shunt pipe (7) and a cooling return pipe (8); the water cooling component is fixedly mounted on the outside of the pump body (1); cooling pipes (9) are fixed at both ends of the cooling shunt pipe (7) and the cooling return pipe (8); the two cooling pipes (9) are both "U"-shaped; the cooling return pipe (8) is connected to the input end of the water cooling component, and the cooling shunt pipe (7) is connected to the output end of the water cooling component; The two ends of the cooling pipe (9) are respectively connected to the inner cavities of the cooling shunt pipe (7) and the cooling return pipe (8), and the "U"-shaped portion of the cooling pipe (9) is in contact with the surface of the envelope (3).

3. The high-efficiency screw dry vacuum pump structure according to claim 1, characterized in that: The driving mechanism comprises a reduction motor (10), a frame (11), and two opposite spur gears (12); the frame (11) is fixedly connected to one end of the pump body (1); the reduction motor (10) is fixedly mounted on the frame (11); a rotor end of the reduction motor (10) is connected to one end of the variable pitch screw (2) via a coupling; the two spur gears (12) are respectively fixedly mounted on one end of the two variable pitch screws (2), and the two spur gears (12) are meshed with each other.

4. The high-efficiency screw dry vacuum pump structure according to claim 1, characterized in that: An air intake outer end cover (13) and an air exhaust outer end cover (14) are also provided on both sides of the pump body (1), and the air intake outer end cover (13) and the air exhaust outer end cover (14) are respectively sealed and connected to the edge of the pump body (1), and an air intake pipe (15) is provided on the top of the air intake outer end cover (13), and the air intake pipe (15) is connected to the air intake end of the pump body (1), and an exhaust pipe (16) is provided on one side of the exhaust outer end cover (14), and the exhaust pipe (16) is connected to the exhaust end of the pump body (1).

5. The high-efficiency screw dry vacuum pump structure according to claim 4, characterized in that: The thickness of the spiral blades of the variable pitch screw (2) gradually increases from one end to the other end.

6. The high-efficiency screw dry vacuum pump structure according to claim 5, characterized in that: The helical line of the variable pitch screw (2) is a sinusoidal helical line.

7. The high-efficiency screw dry vacuum pump structure according to claim 6, characterized in that: The central angle of the helix of the variable pitch screw (2) is 150°-210°.

8. The high-efficiency screw dry vacuum pump structure according to claim 2, characterized in that: The water cooling component comprises a heat exchanger (17), a water cooling block (18), a water tank (19) and a water pump (20); the input end of the heat exchanger (17) is connected to the middle part of the cooling return pipe (8); the input end of the water cooling block (18) is connected to the output end of the heat exchanger (17); the input end of the water tank (19) is connected to the output end of the water cooling block (18); the output end of the water tank (19) is connected to the input end of the water pump (20); and the output end of the water pump (20) is connected to the middle part of the cooling shunt pipe (7).

9. The high-efficiency screw dry vacuum pump structure according to claim 8, characterized in that: The middle parts of the cooling shunt pipe (7) and the cooling return pipe (8) are respectively connected to a connecting pipe 1 (21) and a connecting pipe 2 (22); one end of the connecting pipe 1 (21) is connected to the input end of the heat exchanger (17), and one end of the connecting pipe 2 (22) is connected to the output end of the water pump (20).

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