A dry screw vacuum pump

Abstract

The present application relates to a dry screw vacuum pump, which includes a housing and a rear end cover provided on the housing with a lubrication cavity. An active gear and a driven gear that mesh with each other rotate in the lubrication cavity. The dry screw vacuum pump further includes an iron filings detection device, a driving assembly, a vertical rod and a rotating head. The vertical rod is provided on the rear end cover, the top end of the vertical rod extends out of the rear end cover, and the rotating head rotates at the top end of the vertical rod. The iron filings detection device is used to detect the iron filings content in the lubricating oil in the rear end cover. Let the iron filings content value in the lubricating oil that needs to be replaced be the replacement value. When the iron filings content detected by the iron filings detection device is the replacement value, the driving assembly is used to drive the rotating head to rotate. The operator can judge whether the lubricating oil in the lubrication cavity needs to be replaced by whether the rotating head is driven to rotate by the driving assembly, which helps the operator intuitively judge whether the lubricating oil in the screw vacuum pump should be replaced.

Description

Technical Field

[0001] The present invention relates to the field of vacuum pumps, and particularly to a dry screw vacuum pump. Background Art

[0002] A screw vacuum pump is a gas extraction device that uses a pair of screws to rotate synchronously and at high speed in the pump casing to generate suction and exhaust effects. It is an updated product of oil-sealed vacuum pumps and can pump gas in occasions containing a large amount of water vapor and a small amount of dust. It is widely used in enterprise fields such as pharmaceuticals, chemicals, and semiconductors that have high requirements for clean vacuum.

[0003] The utility model patent with the publication number CN209145867U discloses an improved screw vacuum pump, including a pump body. The pump body includes a casing, a front end cover, and a rear end cover. An active rotor and a driven rotor are installed in the casing. One end of the active rotor is connected to an active screw, and the other end is connected to an active bearing. One end of the driven rotor is connected to a driven screw, and the other end is connected to a driven bearing. The active screw is located inside an active gear, and the driven screw is located inside a driven gear. The active gear and the driven gear are meshed with each other. Heat absorption plates are provided in the casing on both sides of the active rotor and the driven rotor. A heat dissipation channel is provided in the middle of the heat absorption plate. The inlet end of the heat dissipation channel is located on both sides of the active bearing and the driven bearing, and the outlet end of the heat dissipation channel is located on both sides of the active gear and the driven gear. The active screw is connected to the output end of the motor through a coupling.

[0004] The above-mentioned related technical solutions have the following defects: During the meshing process of the above-mentioned active gear and the driven gear, it is necessary to add lubricating oil into the cavity in the rear end cover for accommodating the active gear and the driven gear to reduce the wear of the active gear and the driven gear. After the lubricating oil has been used for a long time, since the iron filings after the wear of the active gear and the driven gear will be mixed in the lubricating oil, it is necessary to replace the lubricating oil in time. At present, the replacement of the lubricating oil is determined according to the experience of the operator and the interval time for replacing the lubricating oil. However, in the case of an inexperienced operator and no record of the last replacement time of the lubricating oil, it will be unclear when to replace the lubricating oil. If the lubricating oil is not replaced in time, the frictional resistance will increase greatly, and these impurities will leave scratches on the gear surface. Summary of the Invention

[0005] In order to facilitate the operator to judge whether the lubricating oil in the screw vacuum pump should be replaced, the present application provides a dry screw vacuum pump.

[0006] The dry screw vacuum pump provided by the present application adopts the following technical solutions:

[0007] A dry screw vacuum pump includes a housing and a rear end cover provided on the housing with a lubricating cavity. An active gear and a driven gear that mesh with each other rotate in the lubricating cavity. It further includes an iron filings detection device, a driving assembly, a vertical rod, and a rotating head. The vertical rod is provided on the rear end cover, and the top end of the vertical rod extends out of the rear end cover. The rotating head rotates at the top end of the vertical rod. The iron filings detection device is used to detect the iron filings content in the lubricating oil in the rear end cover. Let the iron filings content value in the lubricating oil that needs to be replaced be the replacement value. When the iron filings content detected by the iron filings detection device is the replacement value, the driving assembly is used to drive the rotating head to rotate.

[0008] By adopting the above technical solution, the operator can judge whether the lubricating oil in the lubricating cavity needs to be replaced by whether the rotating head is driven to rotate by the driving assembly, which helps the operator intuitively judge whether the lubricating oil in the screw vacuum pump should be replaced.

[0009] Preferably, the iron filings detection device includes a sliding rod, a first magnet, a first spring, and a second magnet. A support base is provided at the bottom end of the rear end cover. The sliding rod slides vertically on the support base. The first magnet is fixed on the outer wall of the top end of the sliding rod. The first spring is used to drive the sliding rod to always slide upward. The first magnet abuts against the bottom surface of the rear end cover without external force. A first chute is provided on the sliding rod. The second magnet slides vertically in the first chute. Both the first magnet and the second magnet are used to adsorb iron filings in the lubricating oil. The influence between the second magnet and the first magnet is weak. When the iron filings content in the lubricating oil does not reach the replacement value, the second magnet abuts against the bottom wall of the first chute and there is a certain distance between it and the bottom wall of the rear end cover. When the iron filings content in the lubricating oil reaches the replacement value, the second magnet abuts against the bottom wall of the rear end cover.

[0010] By adopting the above technical solution, the first magnet abuts against the rear end cover to adsorb the iron filings in the lubricating oil on the inner bottom wall of the lubricating cavity opposite to the first magnet. As the active gear and the driven gear wear, the iron filings will accumulate more and more. When the amount of iron filings in the lubricating oil reaches the replacement value, the second magnet will be sucked up reversely. By whether the second magnet is sucked up reversely, it can be judged whether the iron filings content in the lubricating oil reaches the replacement value.

[0011] Preferably, a groove is provided on the inner bottom wall of the lubricating cavity. The edge of the groove close to the first magnet is in arc transition with the bottom wall of the rear end cover. The groove is opposite to the second magnet.

[0012] By adopting the above technical solution, the iron filings adsorbed by the first magnet will enter the groove along the arc-shaped guiding surface along the edge of the groove. The opening of the groove reduces the distance between the iron filings and the second magnet and increases the sliding range of the second magnet. At the same time, the rotation of the gear will drive the flow of lubricating oil. The lubricating oil flows from one side of the first magnet towards the second magnet side, and can drive some of the iron filings adsorbed by the first magnet into the groove. The iron filings in the groove will be adsorbed by the first magnet at the same time, resulting in more and more iron filings accumulating in the groove, so as to better reverse-adsorb the second magnet.

[0013] Preferably, the driving assembly includes a first driving member, a second spring, a connecting rod and a plurality of blades. The vertical rod slides vertically on the rear end cover. A limiting block is arranged on the outer wall of the vertical rod. A limiting groove is opened in the rear end cover. The limiting block slides vertically in the limiting groove. The second spring is arranged in the limiting groove and drives the limiting block to always move upward and abut against the top wall of the limiting groove. The connecting rod rotates in the vertical rod along the vertical axis direction. The top end of the connecting rod is fixed on the rotating head. The bottom end of the connecting rod extends out of the vertical rod and is located in the lubricating cavity. A plurality of blades are uniformly fixed on the outer wall of the bottom end of the connecting rod in the circumferential direction around the connecting rod. The film formed by the lubricating oil at the meshing position of the driving gear and the driven gear during operation is an adhesion film;

[0014] The blades are close to the meshing position of the driving gear and the driven gear. The connecting rod is located outside the axis direction of the driving gear and the driven gear. When the iron filings content in the lubricating oil does not reach the replacement value, the limiting block always abuts against the top wall of the limiting groove, and some blades are located directly above the adhesion film. When the iron filings content in the lubricating oil reaches the replacement value, the first driving member is used to drive the vertical rod to slide down, and some blades are located at the adhesion film.

[0015] By adopting the above technical solution, when the iron filings content in the lubricating oil reaches the replacement value, the first driving member drives the vertical rod to move down, and some blades are located at the adhesion film. Since the rotation directions of the driving gear and the driven gear are unidirectional, the flow direction of the lubricating oil at the adhesion film is also unidirectional, so it can strike on the blades to drive the blades to rotate, and finally drive the rotating head to rotate through the connecting rod.

[0016] Preferably, the first driving member includes a pull rope and a pulley. The pulley rotates in the sliding rod. The pulley is located below the second magnet. One end of the pull rope is fixed to the bottom end of the second magnet, and the other end of the pull rope passes through the pulley and is fixed to the vertical rod.

[0017] By adopting the above technical solution, when the second magnet is adsorbed by the iron filings, the second magnet drives the vertical rod to move down against the elastic force of the second spring through the pull rope, so that some blades can enter the adhesion film and be driven to rotate by the oil.

[0018] Preferably, it further includes a rotation limiting frame for limiting the rotation of the rotating head. One end of the rotation limiting frame is fixed to the rear end cover, and the other end of the rotation limiting frame is located directly above the rotating head. When the iron chip content in the lubricating oil does not reach the replacement value, the rotating head abuts against the rotation limiting frame.

[0019] By adopting the above technical solution, the rotation limiting frame can limit the rotation of the rotating head when the iron chip content in the lubricating oil does not reach the replacement value, enabling the operator to more conveniently determine whether the rotating head is driven to rotate by the driving component.

[0020] Preferably, the rotating head is a prism.

[0021] By adopting the above technical solution, the prism is more prominent during rotation, better reminding the operator to replace the lubricating oil.

[0022] The technical effects of the present invention are mainly reflected in the following aspects:

[0023] 1. The present invention determines whether the lubricating oil in the lubricating cavity needs to be replaced by whether the rotating head is driven to rotate by the driving component, helping the operator intuitively judge whether the lubricating oil in the screw vacuum pump should be replaced;

[0024] 2. The present invention is provided with a rotation limiting frame, which can limit the rotation of the rotating head when the iron chip content in the lubricating oil does not reach the replacement value, enabling the operator to more conveniently determine whether the rotating head is driven to rotate by the driving component;

[0025] 3. The present invention is provided with a rotating head as a prism, and the prism is more prominent during rotation, better reminding the operator to replace the lubricating oil. Description of the Drawings

[0026] Figure 1 is the overall structural schematic diagram of the embodiment of the present application.

[0027] Figure 2 is along Figure 1 the cross-sectional view taken along the line A-A in

[0028] Figure 3 is Figure 2 the enlarged view at B in

[0029] Figure 4 is Figure 2 the enlarged view at C in

[0030] Figure 5 is the cooperation schematic diagram of the blade, the driving gear and the driven gear in the embodiment of the present application.

[0031] Explanation of the reference numerals in the accompanying drawings: 11. Shell; 12. Rear end cover; 121. Lubrication chamber; 122. Groove; 123. Limiting groove; 13. Support base; 131. Second slide groove; 14. Rotation limiting frame; 15. Blocking cover; 16. Driving gear; 17. Driven gear; 2. Iron chip detection device; 21. Slide rod; 211. First slide groove; 212. Force rod; 22. First magnet; 23. First spring; 24. Second magnet; 3. Driving assembly; 31. Driving member 1; 311. Pull rope; 312. Pulley; 32. Connecting rod; 33. Second spring; 34. Blade; 41. Vertical rod; 411. Limiting block; 42. Rotating head; 5. Adhesion membrane. DETAILED DESCRIPTION

[0032] The following is combined with Figures 1-5 The present application is further described in detail to make the technical solution of the present application easier to understand and grasp.

[0033] The embodiment of the present application discloses a dry screw vacuum pump.

[0034] Reference Figures 1-5 A dry screw vacuum pump of this embodiment includes a housing 11 and a rear end cover 12 mounted on the housing 11 and having a lubrication chamber 121. The lubrication chamber 121 is used to add lubricating oil. A driving gear 16 and a driven gear 17 meshing with each other rotate in the lubrication chamber 121. After the lubricating oil is added, the bottom ends of the driving gear 16 and the driven gear 17 can be immersed. The structure of other parts of the dry screw vacuum pump refers to the patent with application number CN201821728331.7. The air or other medium entering the vacuum pump is extracted through the cooperation of the two rotors.

[0035] Reference Figures 1-5 A dry screw vacuum pump of this embodiment further includes an iron chip detection device 2, a drive assembly 3, a vertical rod 41 and a rotary head 42. The vertical rod 41 is arranged on the rear end cover 12. The top of the vertical rod 41 is located at the center of the top of the rear end cover 12 and extends out of the rear end cover 12. The rotary head 42 rotates at the top of the vertical rod 41. The iron chip detection device 2 is used to detect the iron chip content of the lubricating oil in the rear end cover 12, and the iron chip content value in the lubricating oil that needs to be replaced is the replacement value. The replacement value is a range. When the iron chip content in the lubricating oil exceeds a certain range, it is the replacement value. When the iron chip content detected by the iron chip detection device 2 is the replacement value, the drive assembly 3 is used to drive the rotary head 42 to rotate.

[0036] Reference Figures 1-5 The operator can judge whether the lubricating oil in the lubrication chamber 121 needs to be replaced by judging whether the rotor 42 is driven to rotate by the driving assembly 3, which helps the operator to intuitively judge whether the lubricating oil in the screw vacuum pump should be replaced.

[0037] Reference Figures 1-5, there are two iron filings detection devices 2, and the two iron filings detection devices 2 are respectively close to both sides of the rear end cover 12 and are symmetric with each other along the central vertical plane of the vacuum pump. The iron filings detection device 2 includes a slide bar 21, a first magnet 22, a first spring 23 and a second magnet 24. A support base 13 is provided at the bottom end of the rear end cover 12. A second chute 131 is opened on the rear end cover 12 in the vertical direction. The slide bar 21 slides vertically in the second chute 131. The first spring 23 is located in the second chute 131. The two ends of the first spring 23 respectively abut against the bottom wall of the second chute 131 and the slide bar 21. The first spring 23 is always in a compressed state to drive the slide bar 21 to always slide upward.

[0038] Refer to Figures 1-5 , the first magnet 22 is fixed on the outer wall of the slide bar 21, and the two first magnets 22 are respectively located on both sides of the two slide bars 21. The first magnet 22 abuts against the bottom surface of the rear end cover 12 without external force. A first chute 211 is opened on the top surface of the slide bar 21 in the vertical direction. The second magnet 24 slides vertically in the first chute 211. Both the first magnet 22 and the second magnet 24 are used to adsorb iron filings in the lubricating oil, and the influence between the second magnet 24 and the first magnet 22 is weak.

[0039] Refer to Figures 1-5 , two grooves 122 are opened on the inner bottom wall of the lubricating cavity 121. The positions of the grooves 122 are located at the arc-shaped transition positions of the bottom corners of the lubricating cavity 121. The two grooves 122 respectively face the two second magnets 24. The edge of the groove 122 close to the nearest first magnet 22 is arc-shapedly transitioned with the bottom wall of the rear end cover 12. When the iron filings content in the lubricating oil does not reach the replacement value, the second magnet 24 abuts against the bottom wall of the first chute 211 and there is a certain distance between the second magnet 24 and the bottom wall of the rear end cover 12. When the iron filings content in the lubricating oil reaches the replacement value, the second magnet 24 abuts against the bottom wall of the rear end cover 12.

[0040] Refer to Figures 1-5 , the first magnet 22 abuts against the rear end cover 12 to adsorb the iron filings in the lubricating oil on the inner bottom wall of the lubricating cavity 121 facing the first magnet 22. As the driving gear 16 and the driven gear 17 wear, the iron filings will accumulate more and more. At the same time, the rotation of the gears will drive the lubricating oil to flow. The lubricating oil flows from the side of the first magnet 22 towards the side of the second magnet 24. The iron filings adsorbed by the first magnet 22 will enter the groove 122 along the arc-shaped guiding surface of the edge of the groove 122. The opening of the groove 122 reduces the distance between the iron filings and the first magnet 22 and the second magnet 24. The iron filings in the groove 122 will also be adsorbed by the first magnet 22, reducing the probability that the iron filings are washed away by the lubricating oil again, resulting in the iron filings in the groove 122 being able to accumulate more and more. When the amount of iron filings in the lubricating oil reaches the replacement value, the second magnet 24 will be sucked up. By whether the second magnet 24 is sucked up, it can be judged whether the iron filings content in the lubricating oil reaches the replacement value.

[0041] Referring to Figures 1-5 , the driving assembly 3 includes a first driving member 31, a connecting rod 32, a second spring 33 and a plurality of blades 34. The vertical rod 41 slides vertically on the rear end cover 12. Two limiting blocks 411 are fixed on the outer wall of the vertical rod 41, and the two limiting blocks 411 are respectively located on both sides of the vertical rod 41. Two limiting grooves 123 are formed in the rear end cover 12, and the two limiting blocks 411 slide vertically in the two limiting grooves 123 respectively. The two second springs 33 are respectively arranged in the two limiting grooves 123, and the two ends of the second spring 33 abut against the bottom wall of the limiting groove 123 and the corresponding limiting block 411 respectively. The second spring 33 is always in a compressed state and drives the limiting block 411 to move upward and abut against the top wall of the limiting groove 123.

[0042] Referring to Figures 1-5 , the connecting rod 32 rotates in the vertical rod 41 along the vertical axis direction. The top end of the connecting rod 32 is fixed on the rotating head 42, and the bottom end of the connecting rod 32 extends out of the vertical rod 41 and is located in the lubricating cavity 121. The plurality of blades 34 are uniformly fixed on the outer wall of the bottom end of the connecting rod 32 around the circumferential direction of the connecting rod 32.

[0043] Referring to Figures 1-5 , during the operation of the driving gear 16 and the driven gear 17, the meshing position will drive the lubricating oil to flow unidirectionally. At this time, the flow of the lubricating oil at the meshing position will form a film-like layer, and this layer is the adhesion film 5. The blade 34 is close to the meshing position of the driving gear 16 and the driven gear 17, and the connecting rod 32 is located outside the axis direction of the driving gear 16 and the driven gear 17. When the iron content in the lubricating oil does not reach the replacement value, the limiting block 411 always abuts against the top wall of the limiting groove 123, and some blades 34 are located directly above the adhesion film 5; when the iron content in the lubricating oil reaches the replacement value, the first driving member 31 is used to drive the vertical rod 41 to slide down, and some blades 34 are located at the adhesion film 5.

[0044] Referring to Figures 1-5 , when the iron content in the lubricating oil reaches the replacement value, the first driving member 31 drives the vertical rod 41 to move downward, and some blades 34 are located at the adhesion film 5. Since the rotation direction of the driving gear 16 and the driven gear 17 is unidirectional, the flow direction of the lubricating oil at the adhesion film 5 is also unidirectional. Therefore, it can strike on the blade 34 to drive the blade 34 to rotate, and finally drive the rotating head 42 to rotate through the connecting rod 32.

[0045] Referring to Figures 1-5, the first driving member 31 includes a pulling rope 311 and a pulley 312. The pulley 312 rotates within the sliding rod 21. The pulley 312 is located below the second magnet 24. One end of the pulling rope 311 is fixed to the bottom end of the second magnet 24, and the other end of the pulling rope 311 passes around the pulley 312 and is tied to the vertical rod 41. The pulling rope 311 is always in a taut state. The two pulling ropes 311 are respectively located on both sides of the vertical rod 41. The elastic force of the second spring 33 is less than the adsorption force of the second magnet 24 adsorbed by iron filings. When the second magnet 24 is adsorbed by iron filings, the second magnet 24 drives the vertical rod 41 to move downward against the elastic force of the second spring 33 through the pulling rope 311, so that part of the blades 34 can enter the adhesion film 5 and be driven by the oil to rotate.

[0046] Referring to Figures 1-5 , a rotation limiting frame 14 is fixed on the top surface of the rear end cover 12. One end of the rotation limiting frame 14 is fixed to the rear end cover 12, and the other end of the rotation limiting frame 14 bends towards the side of the rotating head 42 and is located directly above the rotating head 42. When the iron filings content in the lubricating oil does not reach the replacement value, the rotating head 42 abuts against the rotation limiting frame 14. The rotation limiting frame 14 can limit the rotation of the rotating head 42 when the iron filings content in the lubricating oil does not reach the replacement value, so that it is more convenient for the operator to check whether the rotating head 42 is driven to rotate by the driving assembly 3.

[0047] Referring to Figures 1-5 , the rotating head 42 is a prism. The prism is more eye-catching during the rotation process, which can better remind the operator to replace the lubricating oil.

[0048] Referring to Figures 1-5 , although the first magnet 22 and the second magnet 24 will inevitably affect each other, under the action of the pulling rope 311 and the second spring 33, the second magnet 24 will not move under the influence of the first magnet 22. At the same time, under the action of the first spring 23, the first magnet 22 will not move under the influence of the second magnet 24. At the same time, the rear end cover 12 of the present application is made of non-magnetic or weakly magnetic material, and the magnetism is not enough to adsorb iron filings and affect the first magnet 22 and the second magnet 24.

[0049] Referring to Figures 1-5 , a force application rod 212 for hand force application is fixed on the side surface of the sliding rod 21 facing the first magnet 22. An oil change hole is opened on the rear end cover 12, and a plugging cover 15 is threadedly connected to the oil change hole. When it is necessary to replace the lubricating oil in the lubricating cavity 121, the operator can first untie the pulling rope 311 on the sliding rod 21, press the force application rod 212 to drive the vertical rod 41 to move away from the rear end cover 12, so that the first magnet 22 and the second magnet 24 are away from the rear end cover 12. At this time, the iron filings can be washed away during the flow of the lubricating oil, which is convenient for replacing the lubricating oil.

[0050] Of course, the above are only typical examples of this application. In addition, this application can also have many other specific implementation manners. Any technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by this application.

Claims

1. A dry screw vacuum pump, comprising a housing (11) and a rear end cover (12) provided on the housing (11) and having a lubrication chamber (121). An active gear (16) and a driven gear (17) that mesh with each other rotate within the lubrication chamber (121), and it is characterized in that: It further includes an iron filings detection device (2), a driving assembly (3), a vertical rod (41) and a rotating head (42). The vertical rod (41) is arranged on the rear end cover (12), the top end of the vertical rod (41) extends out of the rear end cover (12), the rotating head (42) rotates on the top end of the vertical rod (41), and the iron filings detection device (2) is used to detect the iron filings content in the lubricating oil in the rear end cover (12). Let the iron filings content value in the lubricating oil that needs to be replaced be the replacement value. When the iron filings content detected by the iron filings detection device (2) is the replacement value, the driving assembly (3) is used to drive the rotating head (42) to rotate; The iron filings detection device (2) includes a sliding rod (21), a first magnet (22), a first spring (23) and a second magnet (24). A support base (13) is provided at the bottom end of the rear end cover (12). The sliding rod (21) slides vertically on the support base (13). The first magnet (22) is fixed on the outer wall of the top end of the sliding rod (21). The first spring (23) is used to drive the sliding rod (21) to always slide upward. The first magnet (22) abuts against the bottom surface of the rear end cover (12) without external force. A first chute (211) is formed on the sliding rod (21). The second magnet (24) slides vertically in the first chute (211). Both the first magnet (22) and the second magnet (24) are used to adsorb iron filings in the lubricating oil. The influence between the second magnet (24) and the first magnet (22) is weak. When the iron filings content in the lubricating oil does not reach the replacement value, the second magnet (24) abuts against the bottom wall of the first chute (211) and there is a certain distance between it and the bottom wall of the rear end cover (12). When the iron filings content in the lubricating oil reaches the replacement value, the second magnet (24) abuts against the bottom wall of the rear end cover (12); The driving assembly (3) includes a first driving member (31), a second spring (33), a connecting rod (32) and a plurality of blades (34). The vertical rod (41) slides vertically on the rear end cover (12). A limiting block (411) is provided on the outer wall of the vertical rod (41). A limiting groove (123) is formed in the rear end cover (12). The limiting block (411) slides vertically in the limiting groove (123). The second spring (33) is arranged in the limiting groove (123) and drives the limiting block (411) to always move upward and abut against the top wall of the limiting groove (123). The connecting rod (32) rotates along the vertical axis direction in the vertical rod (41). The top end of the connecting rod (32) is fixed on the rotating head (42). The bottom end of the connecting rod (32) extends out of the vertical rod (41) and is located in the lubricating cavity (121). A plurality of blades (34) are evenly fixed on the outer wall of the bottom end of the connecting rod (32) in the circumferential direction around the connecting rod (32). The film formed by the lubricating oil at the meshing part during the operation of the driving gear (16) and the driven gear (17) is an adhesion film (5); The blade (34) is close to the meshing position of the driving gear (16) and the driven gear (17). The connecting rod (32) is located outside the driving gear (16) and the driven gear (17) in the axial direction. When the iron content in the lubricating oil does not reach the replacement value, the limiting block (411) always abuts against the top wall of the limiting groove (123), and part of the blade (34) is located directly above the adhesion film (5). When the iron content in the lubricating oil reaches the replacement value, the first driving member (31) is used to drive the vertical rod (41) to slide down, and part of the blade (34) is located at the adhesion film (5). The first driving member (31) includes a pulling rope (311) and a pulley (312). The pulley (312) rotates in the sliding rod (21). The pulley (312) is located below the second magnet (24). One end of the pulling rope (311) is fixed to the bottom end of the second magnet (24), and the other end of the pulling rope (311) is fixed to the vertical rod (41) after passing through the pulley (312).

2. The dry screw vacuum pump according to claim 1, wherein: A groove (122) is formed in the bottom wall of the lubricating cavity (121). The edge of the groove (122) close to the first magnet (22) is in arc transition with the bottom wall of the rear end cover (12). The groove (122) faces the second magnet (24).

3. A dry screw vacuum pump according to claim 1, characterized in that: It further includes a rotation limiting frame (14) for limiting the rotation of the rotating head (42). One end of the rotation limiting frame (14) is fixed to the rear end cover (12), and the other end of the rotation limiting frame (14) is located directly above the rotating head (42). When the iron content in the lubricating oil does not reach the replacement value, the rotating head (42) abuts against the rotation limiting frame (14).

4. A dry screw vacuum pump according to claim 1, characterized in that: The rotating head (42) is a prism.

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