Three-shaft hybrid pump

Abstract

A three-shaft hybrid pump, comprising a pump body (1), an intermediate connecting shaft (9), a first connecting shaft (10) and a second connecting shaft (11). A first-stage Roots pump body chamber (2), a second-stage Roots pump body chamber (3) and a screw pump body chamber (4) independent of each other are successively provided in the pump body (1). Two mutually engaged first-stage Roots rotor parts (12) are provided in the first-stage Roots pump body chamber (2), the two first-stage Roots rotor parts (12) being respectively mounted on the intermediate connecting shaft (9) and the first connecting shaft (10). Two mutually engaged second-stage Roots rotor parts (13) are provided in the second-stage Roots pump body chamber (3), the two second-stage Roots rotor parts (13) being respectively mounted on the intermediate connecting shaft (9) and the second connecting shaft (11). Two mutually engaged screw rotor parts (14) are provided in the screw pump body chamber (4), the two screw rotor parts (14) being respectively mounted on the intermediate connecting shaft (9) and the first connecting shaft (10).

Description

A three-shaft hybrid pump TECHNICAL FIELD

[0001] The present application relates to a vacuum pump, in particular to a three-shaft hybrid pump. BACKGROUND

[0002] There are many classifications of vacuum pumps, and different vacuum pumps are used in different industries, such as Roots vacuum pumps and screw vacuum pumps, which are used separately or in combination. In the conventional way, such as patent number: CN202121962223.8, patent name: high-efficiency energy-saving Roots screw vacuum pump set based on industry, this structure has the following disadvantages:

[0003] 1. The screw pump is arranged below the Roots pump, which occupies a large space;

[0004] 2. The Roots pump and the screw pump each need a separate motor to drive, which not only has a higher cost, but also has higher energy consumption;

[0005] 3. The outlet temperature of the screw pump is high, which is easy to damage, and at the same time, in an environment with dust, dust blocking phenomenon is easy to occur, and the maintenance rate is relatively high. SUMMARY

[0006] The present application aims to provide a three-shaft hybrid pump, which can reduce the occupation of space, ensure the vacuum effect, reduce the maintenance rate, prolong the service life, and reduce the assembly difficulty.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is: a three-shaft hybrid pump, comprising a pump body and a connecting shaft rotatably installed in the pump body;

[0008] The pump body is sequentially arranged with a first-stage Roots pump body cavity, a second-stage Roots pump body cavity and a screw pump body cavity along the axis direction of the connecting shaft;

[0009] The pump body is provided with an air inlet, an air outlet, an intermediate connecting channel and a connecting channel, the air inlet connects the first-stage Roots pump body cavity with the outside atmosphere, the air outlet connects the screw pump body cavity with the outside atmosphere, the intermediate connecting channel connects the first-stage Roots pump body cavity and the second-stage Roots pump body cavity, and the connecting channel connects the second-stage Roots pump body cavity with the screw pump body cavity;

[0010] The connecting shaft comprises a middle connecting shaft, a first connecting shaft and a second connecting shaft arranged in parallel on both sides of the middle connecting shaft, respectively;

[0011] The first-stage Roots pump cavity is internally provided with two first-stage Roots rotor components which are mutually engaged, the two first-stage Roots rotor components are respectively installed on the intermediate connecting shaft and the first connecting shaft, and when the two first-stage Roots rotor components rotate, the fluid entering the air inlet is sent into the second-stage Roots pump cavity through the intermediate connecting channel.

[0012] The second-stage Roots pump cavity is internally provided with two second-stage Roots rotor components which are mutually engaged, the two second-stage Roots rotor components are respectively installed on the intermediate connecting shaft and the second connecting shaft, and when the two second-stage Roots rotor components rotate, the fluid entering the intermediate connecting channel is sent into the screw pump cavity through the connecting channel.

[0013] The screw pump cavity is internally provided with two screw rotor components which are mutually engaged, the two screw rotor components are respectively installed on the intermediate connecting shaft and the first connecting shaft, and when the two screw rotor components rotate, the fluid sent into the screw pump cavity through the connecting channel is discharged from the exhaust port.

[0014] In the technical scheme, the intermediate connecting shaft is inserted into the first-stage Roots pump cavity, the second-stage Roots pump cavity and the screw pump cavity;

[0015] One end of the second connecting shaft is inserted into the second-stage Roots pump cavity;

[0016] One end of the first connecting shaft is located in the screw pump cavity, and the other end is located in the first-stage Roots pump cavity.

[0017] In the technical scheme, the first-stage Roots pump cavity is arranged between the second-stage Roots pump cavity and the gear cavity, and the heads of the three connecting shafts are respectively inserted into the gear cavity;

[0018] Each of the heads of the connecting shafts is respectively provided with a gear, and the gears at the heads of the first connecting shaft and the second connecting shaft are respectively engaged with the gear at the head of the intermediate connecting shaft.

[0019] In the technical scheme, the end of the intermediate connecting shaft sequentially passes through the first-stage Roots pump cavity, the second-stage Roots pump cavity and is inserted into the screw pump cavity, and the end of the intermediate connecting shaft and the end of the screw pump cavity have a spacing therebetween;

[0020] And / or, the pump body beside the axis of the first-stage Roots pump cavity is internally provided with a second displacement hole which communicates the gear cavity and the second-stage Roots pump cavity, the second connecting shaft is inserted into the second displacement hole, the end of the second connecting shaft is arranged in the second-stage Roots pump cavity and is rotationally connected with the pump body;

[0021] And / or, the first displacement hole is arranged in the pump body beside the secondary Roots pump cavity axis and communicates the primary Roots pump cavity and the screw pump cavity, the middle part of the first connecting shaft is inserted into the first displacement hole, and the first connecting shaft on the two sides of the first displacement hole is respectively installed on the primary Roots rotor component and the screw rotor component.

[0022] In the technical scheme, the pump body comprises a gear shell, a first bearing shell, a Roots pump body, a second bearing shell and a screw pump body which are sequentially and sealingly connected,

[0023] The primary Roots pump cavity and the secondary Roots pump cavity are arranged in the Roots pump body, one end of the primary Roots pump cavity is communicated with the head of the Roots pump body, and one end of the secondary Roots pump cavity is communicated with the tail end of the Roots pump body;

[0024] The first bearing shell and the second bearing shell are sealingly connected with the head and the tail end of the Roots pump body, respectively;

[0025] The screw pump cavity is arranged in the screw pump body, one end of the screw pump cavity is communicated with the head of the screw pump cavity, and the head of the screw pump body is sealingly connected with the second bearing shell;

[0026] The gear cavity is arranged in the gear shell and communicated with the tail end of the gear shell, and the tail end of the gear shell is sealingly connected with the first bearing shell.

[0027] In the technical scheme, the first bearing cavity is arranged in the first bearing shell, the heads of the three connecting shafts are respectively rotatably connected with the first bearing cavity through bearings;

[0028] The second bearing cavity is arranged in the second bearing shell, and the tail end of the second connecting shaft is rotatably connected with the second bearing cavity through a bearing;

[0029] The middle part of the intermediate connecting shaft and the first connecting shaft is rotatably connected with the second bearing cavity through a bearing, respectively;

[0030] And / or, the heads of the three connecting shafts are respectively inserted into the gear cavity through the corresponding bearings;

[0031] The head of each connecting shaft is respectively provided with a gear, and the gears on the heads of the first connecting shaft and the second connecting shaft are respectively engaged with the two sides of the gear on the head of the intermediate connecting shaft.

[0032] In the technical scheme, the first bearing shell and the second bearing shell are respectively provided with cooling cavities which are wrapped in the first bearing cavity and the second bearing cavity, and the first bearing shell and the second bearing shell are respectively provided with a cooling medium inlet and a cooling medium outlet which are communicated with the corresponding cooling cavities.

[0033] In the technical scheme, the head of the pump body is provided with a driving device, and the driving device is configured to drive one of the gears or one of the shafts.

[0034] In the technical scheme, the screw rotor component is mounted on the outer surface of the corresponding shaft, and a micro gap is formed between the end of the screw rotor component and the end of the screw pump body cavity.

[0035] In addition, the primary Roots rotor component and the secondary Roots rotor component are integrated with the corresponding shaft.

[0036] In the technical scheme, the outer wall of the pump body is further provided with a notch in communication with the connecting channel, and the pump body is provided with a sealing component for sealing the notch.

[0037] In addition, the fluid treatment component can be detachably mounted in the connecting channel at the notch.

[0038] Compared with the prior art, the application has the following advantages due to the use of the technical scheme:

[0039] 1. In the application, the Roots pump and the screw pump can be simultaneously driven by the same driving device, which is more cost-effective and occupies less space than the previous structure with two motors arranged above and below, and can also reduce transportation costs.

[0040] 2. In the application, three shafts are used to connect the two-stage Roots pump rotor and the screw pump rotor, which makes the assembly of the Roots pump more difficult and more convenient, facilitates assembly and debugging, and ensures the assembly qualification rate and quality of the pump body.

[0041] 3. In the application, the primary Roots pump body cavity and the secondary Roots pump body cavity are arranged on both sides of the Roots pump body, which makes the machining more convenient and ensures the precision during assembly, improves the assembly quality, ensures the vacuum pumping effect, and effectively reduces the maintenance rate during subsequent use and prolongs the service life.

[0042] 4. In the application, a two-stage Roots pump and a screw pump are used, the Roots pump constitutes a booster pump, and the screw pump constitutes a vacuum pump, which can effectively improve the vacuum pumping effect.

[0043] 5. In the application, the two-stage Roots pump is arranged in front of the screw pump, so that the Roots pump generates compression at each stage, the heat is not concentrated too much at the exhaust port of the screw pump, the temperature of the exhaust port is prevented from being too high to cause coking and blockage of the carbon-hydrogen mixture, the smoothness of the vacuum pumping is ensured, the screw pump is prevented from being damaged, the maintenance rate is reduced, and the service life is prolonged.

[0044] 6. The two-stage Roots pump is used for pumping in the application, which can effectively prevent dust and other impurities from entering the screw pump, prevent the occurrence of powder blocking and clogging, reduce the maintenance rate and prolong the service life. BRIEF DESCRIPTION OF DRAWINGS

[0045] Fig. 1 is a structural schematic diagram in the embodiment one of the application;

[0046] Fig. 2 is a top view of Fig. 1;

[0047] Fig. 3 is a sectional structural schematic diagram of A-A in Fig. 1;

[0048] Fig. 4 is a sectional structural schematic diagram of F-F in Fig. 2;

[0049] Fig. 5 is a local enlarged view of the connecting channel in the embodiment one of the application;

[0050] Fig. 6 is a sectional structural schematic diagram of B-B in Fig. 1;

[0051] Fig. 7 is a sectional structural schematic diagram of C-C in Fig. 1;

[0052] Fig. 8 is a sectional structural schematic diagram of D-D in Fig. 1;

[0053] Fig. 9 is a sectional structural schematic diagram of E-E in Fig. 1;

[0054] Fig. 10 is a local sectional structural schematic diagram of the connecting part between the screw rotor and the intermediate connecting shaft in the embodiment one of the application.

[0055] Wherein: 1, pump body; 2, first-stage Roots pump body cavity; 3, second-stage Roots pump body cavity; 4, screw pump body cavity; 5, air inlet; 6, exhaust port; 7, intermediate connecting channel; 8, connecting channel; 9, intermediate connecting shaft; 10, first connecting shaft; 11, second connecting shaft; 12, first-stage Roots rotor part; 13, second-stage Roots rotor part; 14, screw rotor part; 15, stepped hole; 16, spline; 17, stepped limiting part; 18, bolt; 19, sealing end cover; 20, gear cavity; 21, gear; 22, second allowing hole; 23, first allowing hole; 24, gear housing; 25, first bearing housing; 26, Roots pump body; 27, second bearing housing; 28, screw pump body; 29, first bearing cavity; 30, bearing; 31, second bearing cavity; 32, stepped through hole; 33, stepped cover plate; 34, driving device; 35, sealing part; 36, Roots connecting channel; 37, screw connecting channel; 38, frame; 39, sealing cover; 40, connecting cavity; 41, through slot. DETAILED DESCRIPTION

[0056] The application will be further described in conjunction with the drawings and embodiments:

[0057] Embodiment one: refer to figures 1-10, a three-axis mixed pump, comprising a pump body 1 and a connecting shaft rotatingly installed in the pump body;

[0058] The pump body 1 is sequentially arranged with a first-stage Roots pump cavity 2, a second-stage Roots pump cavity 3 and a screw pump cavity 4 along the axis direction of the connecting shaft;

[0059] The pump body 1 is provided with an air inlet 5, an air outlet 6, an intermediate connecting channel 7 and a connecting channel 8, the air inlet 5 connects the first-stage Roots pump cavity 2 with the outside atmosphere, the air outlet 6 connects the screw pump cavity 4 with the outside atmosphere, the intermediate connecting channel 7 connects the first-stage Roots pump cavity 2 and the second-stage Roots pump cavity 3, and the connecting channel 8 connects the second-stage Roots pump cavity 3 with the screw pump cavity 4;

[0060] The connecting shaft comprises an intermediate connecting shaft 9, a first connecting shaft 10 and a second connecting shaft 11 which are respectively arranged in parallel on both sides of the intermediate connecting shaft 9.

[0061] For example, in the direction shown in the figures, the first-stage Roots pump cavity 2, the second-stage Roots pump cavity 3 and the screw pump cavity 4 are arranged in sequence from front to back (the head is the front end and the tail is the rear end), and the three connecting shafts are arranged on the same horizontal plane. For example, in the front end view, the first connecting shaft 10 is arranged on the right side of the intermediate connecting shaft 9, and the second connecting shaft 11 is arranged on the left side of the intermediate connecting shaft 9. The intermediate connecting channel is arranged on the opposite side of the air inlet, and the connecting channel is arranged on the opposite side of the intermediate connecting channel. In this embodiment, the bottom of the pump body is placed on the ground, or the bottom of the pump body serves as a mounting and fixing part. Therefore, the air inlet is arranged on the top of the pump body, the intermediate connecting channel is arranged on the bottom of the pump body, the connecting channel is arranged on the top of the pump body, the connecting channel is arranged on the rear end of the air inlet, and the air outlet is arranged on the rear end surface of the pump body.

[0062] Referring to figures 3, 4, 7-9, the first-stage Roots pump cavity 2 is provided with two first-stage Roots rotor components 12 which are in meshing engagement, and the two first-stage Roots rotor components 12 are respectively installed on the intermediate connecting shaft 9 and the first connecting shaft 10. When the two first-stage Roots rotor components 12 rotate, the fluid entering the air inlet 5 is sent into the second-stage Roots pump cavity 3 through the intermediate connecting channel 7;

[0063] The second-stage Roots pump cavity 3 is provided with two second-stage Roots rotor components 13 which are in meshing engagement, and the two second-stage Roots rotor components 13 are respectively installed on the intermediate connecting shaft 10 and the second connecting shaft 11. When the two second-stage Roots rotor components 13 rotate, the fluid entering the intermediate connecting channel 7 is sent into the screw pump cavity 4 through the connecting channel 8;

[0064] The screw pump cavity 4 is provided with two screw rotor components 14 which are meshed with each other, the two screw rotor components 14 are respectively installed on the intermediate connecting shaft 9 and the first connecting shaft 10, when the two screw rotor components 14 rotate, the fluid sent into the screw pump cavity 4 from the connecting channel 8 is discharged from the exhaust port 6.

[0065] In the embodiment, the primary Roots pump cavity and the secondary Roots pump cavity are "∞" shaped cavities (8-shaped structure arranged horizontally), which are composed of two cylindrical cavities which are communicated with each other at inner ends, the two connecting shafts inserted into the corresponding Roots pump cavities are coaxially arranged with the two cylindrical cavities respectively, the primary and secondary Roots rotor components are also "∞" shaped structures (8-shaped structure arranged horizontally), the outer surfaces of the opposite two ends thereof are attached to the inner walls of the corresponding Roots pump cavities or there are micro gaps between the outer surfaces of the opposite two ends thereof and the inner walls of the corresponding Roots pump cavities (preferably, there are micro gaps to ensure that the corresponding Roots rotor components will not be in contact with the inner walls of the corresponding Roots pump cavities to be scratched when the Roots rotor components rotate), the rotating directions of the first connecting shaft and the second connecting shaft are the same, but are opposite to the rotating direction of the intermediate connecting shaft, for example, from the perspective of the front end, the intermediate connecting shaft rotates clockwise, the first connecting shaft and the second connecting shaft rotate counterclockwise (if the intermediate connecting shaft rotates counterclockwise, the first connecting shaft and the second connecting shaft rotate clockwise), the primary Roots pump cavity above the two primary Roots rotor components which are meshed with each other is an independent space, the primary Roots pump cavity below the two primary Roots rotor components is another independent space, the secondary Roots pump cavity above the two secondary Roots rotor components which are meshed with each other is an independent space, the secondary Roots pump cavity below the two secondary Roots rotor components is another independent space. In this way, when the two primary Roots rotor components rotate, the gas entering the inlet is pressed into the space below the two primary Roots rotor components, and then is sent into the secondary Roots pump cavity through the intermediate connecting channel, and is in the secondary Roots pump cavity below the two secondary Roots rotor components, then when the two secondary Roots rotor components rotate, the gas below the two secondary Roots rotor components is sent into the secondary Roots pump cavity above the two secondary Roots rotor components, and is sent into the front end of the screw pump cavity through the connecting channel, wherein, there are micro gaps between the outer surfaces of the two screw rotor components and the inner surfaces of the corresponding screw pump cavities, the outer surfaces of the screw rotor components have helical grooves (helical exhaust grooves), the width of the helical grooves gradually decreases from front to back, the screw rotor components beside the helical grooves are meshed with the helical grooves of the adjacent screw rotor components (and there are gaps between them, and they will not be in contact with each other), in this way, the fluid sent into the screw pump cavity from the connecting channel is discharged rearward through the gaps of the helical grooves, and is discharged through the exhaust port, so as to realize the action of vacuumizing.

[0066] The two screw rotor components 14 are respectively installed on the outer surface of the end of the intermediate connecting shaft 9 and the first connecting shaft 10, and a micro gap is formed between the end of the screw rotor component 14 and the end of the screw pump cavity 4.

[0067] In the embodiment, the middle part of the screw rotor component 14 is provided with a coaxial stepped hole 15, which includes a front hole and a rear hole, the diameter of the front hole is smaller than that of the rear hole, the diameter of the front hole matches the outer diameter of the connecting shaft, the rear end of the first connecting shaft and the intermediate connecting shaft is provided with a threaded hole, the outer surface of the connecting shaft in the screw pump cavity 4 is provided with a key groove, the front hole is also provided with a key groove, the connecting shaft and the screw rotor component 14 are connected through the spline 16, the inner end of the spline 16 is clamped in the key groove of the connecting shaft, and the outer end of the spline is clamped in the key groove of the front hole, so that the circumferential limiting between the screw rotor component and the connecting shaft is realized, and relative rotation of the two is prevented. A stepped limiting piece 17 is installed in the rear hole, the front side of the middle part of the stepped limiting piece 17 abuts against the front end surface of the rear hole, the front end of the stepped limiting piece abuts against the rear side surface of the connecting shaft, then the bolt 18 passes through the threaded hole in the rear end of the connecting shaft and the stepped limiting piece 17 to be connected, so that the screw rotor component and the connecting shaft are axially fixed, and the two are prevented from moving away from each other in the axial direction. Further, a sealing end cover 19 is installed at the rear end of the screw rotor component, the sealing end cover 19 seals the rear end of the rear hole, so that the gas can be prevented from entering the rear hole, and the vacuum pumping effect is ensured. The rear end of the intermediate connecting shaft and the first connecting shaft is not in contact with and connected to the rear end surface of the screw pump cavity, and the two have an axial spacing, that is, the first connecting shaft, the intermediate connecting shaft and the screw rotor component are a cantilever screw structure, the front end of the screw rotor component is rotationally supported through the connecting part of the connecting shaft and the pump body, and the rear end is not limited. In this structure, it is convenient to debug and adjust the spacing between the two screw rotor components during assembly, so as to ensure the meshing between the two. The two screw rotor components do not contact each other, but only have a micro gap therebetween, and do not rub each other, so as to ensure the vacuum pumping quality.

[0068] Referring to FIGS. 3, 4, 7 and 8, the intermediate connecting shaft 9 is inserted into the first-stage Roots pump cavity 2, the second-stage Roots pump cavity 3 and the screw pump cavity 4;

[0069] One end of the second connecting shaft 11 is inserted into the second-stage Roots pump cavity 3;

[0070] One end of the first connecting shaft 10 is located in the screw pump cavity 4, and the other end is located in the first-stage Roots pump cavity 2.

[0071] The two first-stage Roots rotor components 12 in the first-stage Roots pump cavity 2 are respectively integrated with the intermediate connecting shaft 9 and the first connecting shaft 10, and the two second-stage Roots rotor components 13 in the second-stage Roots pump cavity 3 are respectively integrated with the intermediate connecting shaft 9 and the second connecting shaft 11.

[0072] In this way, only the middle connecting shaft is arranged in the three pump cavities, the first connecting shaft is arranged in the first-stage Roots pump cavity and the screw pump cavity, and the second connecting shaft is arranged in the second-stage Roots pump cavity. Therefore, when assembling, the three connecting shafts are arranged to facilitate adjustment of the micro gap between the corresponding rotor components and the rotor components, and facilitate adjustment of the micro gap between the rotor components and the inner wall of the corresponding pump cavity. Therefore, the assembly and adjustment are facilitated, the micro gap is adjusted and assembled, and the service life is effectively prolonged and the maintenance rate is reduced during use. Meanwhile, only the middle connecting shaft needs to be integrally machined with the first-stage Roots rotor component and the second-stage Roots rotor component, only the first connecting shaft needs to be integrally machined with the first-stage Roots rotor component, and only the second connecting shaft needs to be integrally machined with the second-stage Roots rotor component. Therefore, the machining difficulty and cost are reduced, and the debugging and adjustment are facilitated during assembly.

[0073] Referring to FIGS. 3, 4, and 6, the pump body 1 of the head of the first-stage Roots pump cavity 2 is further provided with a gear cavity 20, the first-stage Roots pump cavity 2 is arranged between the second-stage Roots pump cavity 3 and the gear cavity 20, and the heads of the three connecting shafts are respectively inserted into the gear cavity 20.

[0074] The head of each connecting shaft is respectively provided with a gear 21, and the gears 21 at the heads of the first connecting shaft 10 and the second connecting shaft 11 are respectively engaged with the two sides of the gear 21 at the head of the middle connecting shaft 9. In this way, when one of the connecting shafts is driven to rotate, the three connecting shafts will rotate at the same time, the first connecting shaft and the second connecting shaft rotate in the same direction, and the middle connecting shaft rotates in the opposite direction.

[0075] Referring to FIGS. 3, 4, 7, and 8, the end of the middle connecting shaft 9 sequentially passes through the first-stage Roots pump cavity 2, the second-stage Roots pump cavity 3, and is inserted into the screw pump cavity 4, and the end of the middle connecting shaft 9 has a spacing with the end of the screw pump cavity 4.

[0076] The pump body 1 beside the axis of the first-stage Roots pump cavity 2 is provided with a second displacement hole 22 communicating the gear cavity 20 and the second-stage Roots pump cavity 3, the middle of the second connecting shaft 11 is inserted into the second displacement hole 22, and the end of the second connecting shaft 11 is arranged in the second-stage Roots pump cavity 3 and is rotationally connected with the pump body 1.

[0077] In this way, the second displacement hole and the first-stage Roots pump cavity are independent of each other and do not affect each other. Therefore, when assembling, the first-stage Roots rotor component and the second-stage Roots rotor component are assembled respectively without collision problems, and the assembly and debugging are facilitated.

[0078] Referring to Figs. 3, 4, 7 and 8, the pump body 1 has a first clearance hole 23 communicating the primary Roots pump cavity 2 and the screw pump cavity 4, and the middle part of the first connecting shaft 10 is inserted into the first clearance hole 23, and the first connecting shaft 10 on both sides of the first clearance hole 23 is respectively installed with the primary Roots rotor component 12 and the screw rotor component 14. In this way, the secondary Roots pump cavity and the first clearance hole are independent of each other and do not interfere with each other, facilitating assembly and debugging.

[0079] Referring to Figs. 3, 4, 6-9, the pump body 1 comprises a gear housing 24, a first bearing housing 25, a Roots pump body 26, a second bearing housing 27 and a screw pump body 28 connected in sequence,

[0080] The primary Roots pump cavity 2 and the secondary Roots pump cavity 3 are arranged in the Roots pump body 26, and one end of the primary Roots pump cavity 2 is in communication with the head of the Roots pump body 26, and one end of the secondary Roots pump cavity 3 is in communication with the tail end of the Roots pump body 26;

[0081] The first bearing housing 25 and the second bearing housing 27 are respectively sealingly connected with the head and the tail end of the Roots pump body 26;

[0082] The screw pump cavity 4 is arranged in the screw pump body 28, and one end of the screw pump cavity 4 is in communication with the head of the screw pump body 28, and the head of the screw pump body 26 is sealingly connected with the second bearing housing 27;

[0083] The gear housing 24 is provided with a gear cavity 20 in communication with the tail end of the gear housing 24, and the tail end of the gear housing 24 is sealingly connected with the first bearing housing 25.

[0084] The first bearing housing 25 is provided with a first bearing cavity 29, and the heads of the three connecting shafts are respectively rotatably connected with the first bearing cavity 29 through bearings 30;

[0085] The second bearing housing 27 is provided with a second bearing cavity 31, and the tail end of the second connecting shaft 11 is rotatably connected with the second bearing cavity 31 through a bearing 30;

[0086] The middle part of the intermediate connecting shaft 9 and the first connecting shaft 10 is respectively rotatably connected with the second bearing cavity 31 through a bearing 30;

[0087] The heads of the three connecting shafts are respectively inserted into the gear cavity 20 through the corresponding bearings 30.

[0088] The head of each connecting shaft is respectively provided with a gear 21, and the gears at the heads of the first connecting shaft 10 and the second connecting shaft 11 are respectively engaged with the two sides of the gear 21 at the head of the intermediate connecting shaft 9.

[0089] In the embodiment, the first-stage Roots pump cavity and the second-stage Roots pump cavity are in a certain misalignment relationship, the first-stage Roots pump cavity is arranged at the front end of the second-stage Roots pump cavity and close to the right side of the Roots pump body, and the second-stage Roots pump cavity is arranged close to the left side of the Roots pump body, with a misalignment therebetween. Meanwhile, in order to facilitate the assembly of the intermediate connecting shaft and the Roots pump body, a stepped through hole 32 is arranged on the Roots pump body 26 between the first-stage Roots pump cavity 2 and the second-stage Roots pump cavity 3 and communicates the two, and the stepped through hole is coaxial with the intermediate connecting shaft, and the size of the stepped through hole is slightly larger than the outer dimensions of the first-stage Roots rotor component and the second-stage Roots rotor component, so that when the intermediate connecting shaft needs to be inserted into the Roots pump body, the first-stage Roots rotor component or the second-stage Roots rotor component is inserted into the corresponding Roots pump cavity through the stepped through hole. In order to block the gap between the first-stage Roots pump cavity, the second-stage Roots pump cavity and the stepped through hole, thereby ensuring that the two stages are in turn in vacuum, a stepped cover plate 33 with a hole in the middle is arranged above the stepped through hole, and the stepped cover plate blocks the gap between the stepped through hole and the intermediate connecting shaft. Preferably, since the intermediate connecting shaft has the first-stage Roots rotor component and the second-stage Roots rotor component in an integrated structure, and the first-stage Roots rotor component and the second-stage Roots rotor component have a spacing therebetween, the stepped cover plate adopts a two-piece structure, i.e., a first cover plate and a second cover plate, and recesses matching the connecting rods are arranged at the opposite ends of the first cover plate and the second cover plate, and the two recesses constitute a hole matching the intermediate connecting shaft, so that in the assembly, taking the case that the front end of the stepped cover plate is in the second-stage Roots pump cavity as an example, the first cover plate and the second cover plate are first respectively clamped into the intermediate connecting shaft outside the first-stage Roots rotor component and the second-stage Roots rotor component, and then the intermediate connecting shaft and the first-stage Roots rotor component are inserted into the first-stage Roots pump cavity through the stepped through hole, and then the cover plate and the Roots pump body are locked, thereby completing the assembly of the intermediate connecting shaft and the Roots pump body. Preferably, in order to prevent the cover plate from rotating with the intermediate connecting shaft and causing relative friction with the Roots pump body when the intermediate connecting shaft rotates, the stepped through hole and the cover plate can be arranged in a non-circular structure, so that after installation, the cover plate is prevented from rotating with the intermediate connecting shaft, and also plays a role in alignment during assembly.

[0090] The front end of the intermediate connecting channel communicates with the bottom of the first-stage Roots pump cavity, and the rear end of the intermediate connecting channel communicates with the bottom of the second-stage Roots pump cavity.

[0091] In the embodiment, the first-stage Roots pump cavity and the second-stage Roots pump cavity are directly arranged on the same Roots pump body, so that the same reference can be used for machining and positioning when the Roots pump body is machined, the machining precision of the Roots pump body can be improved, and the vacuum pumping effect after subsequent assembly is ensured. If the Roots pump body adopts a segmented structure, i.e., the first-stage Roots pump cavity and the second-stage Roots pump cavity are machined respectively and then assembled, the machining references are different, the machining precision and error exist deviation, the assembly difficulty and precision of the Roots pump (the Roots pump formed after the Roots rotor components are installed in the corresponding Roots pump cavity) exist deviation, the subsequent assembly difficulty is increased, and the service life is also affected. Therefore, in the embodiment, the first-stage Roots pump cavity and the second-stage Roots pump cavity are arranged on the same Roots pump body, the machining precision of the first-stage Roots pump cavity and the second-stage Roots pump cavity is effectively ensured, the machining difficulty is reduced, the subsequent assembly and debugging difficulty is reduced, the vacuum pumping effect during use is effectively ensured, the service life is prolonged, and the maintenance rate is reduced.

[0092] Meanwhile, in the embodiment, the first bearing shell and the second bearing shell are arranged at the two ends of the Roots pump body, the corresponding bearing cavities are arranged in the corresponding bearing shells, the first bearing cavities are arranged on the front end faces (heads) of the first bearing shells and depart from the Roots pump body. The first bearing cavities are three, the front end (head) of each connecting shaft is rotatably connected with a first bearing cavity through a bearing, the first bearing shell has a hole position on the upper surface to communicate the first bearing shell with the rear end face of the first bearing shell, so that the connecting shaft can be inserted into the Roots pump body. The second bearing cavities are also three, the second bearing cavities are arranged on the rear end faces (ends) of the second bearing shells and depart from the Roots pump body, the rear end (end) or the corresponding middle part of each connecting shaft is rotatably connected with a second bearing cavity through a bearing. The second bearing shell has a hole position on the upper surface to communicate the front end face of the second bearing shell with the second bearing cavity, so that the corresponding connecting shaft can pass through the second bearing shell and be inserted into the second bearing cavity to be connected with the bearing.

[0093] Wherein, when assembling the mixed pump, first insert the three shafts into the roots pump body, at this time, the first and second roots rotor components are also simultaneously installed into the corresponding roots pump body cavities, at this time, the gaps between the corresponding roots rotor components, the gaps between the roots rotor components and the roots pump body cavities have not been adjusted, then install the first and second bearing housings at the two ends of the roots pump body, seal the first and second roots pump body cavities, then install bearings at the two ends of the shafts (the bearings are installed and limited by the bearing seats, the bearing seats clamp the outer steel rings of the bearings), so that the bearings at the two ends are installed into the first and second bearing cavities, in this process, by adjusting the gaps between the bearings and the first and second bearing cavities, the positions of the corresponding shafts are adjusted, for adjusting the gaps between the two first roots rotor components, the first roots rotor component and the first roots pump body cavity, the gaps between the two second roots rotor components, the second roots rotor component and the second roots pump body cavity, so as to realize the installation and adjustment of the roots rotor components. After the installation is completed, then install the two screw rotor components on the corresponding two shafts, after the installation of the screw rotor components is completed, then install the screw pump body, wherein, the screw pump body cavity is in communication with the front end of the screw pump body, directly seal and connect the front end of the screw pump body and the second bearing housing, at this time, the screw rotor components are installed into the screw pump body cavity. Then install the gear to the head of the shaft, then install the gear housing to the front end of the first gear housing, so that the gear is in the gear cavity, the installation is completed.

[0094] At the same time, the stepped limiting piece limits the freedom of the screw rotor component moving backward, the front end of the screw rotor component abuts on the bearing in the second bearing cavity, so as to limit the freedom of the screw rotor component moving forward, and then realize the axial limiting of the screw rotor component.

[0095] Referring to Figs. 3 and 4, the head of the pump body 1 is provided with a driving device 34 configured to drive one of the gears 21 or one of the connecting shafts. In the present application, the driving device is an electric motor or a combination of an electric motor and a speed reducer. In the present embodiment, the driving device comprises an electric motor mounted on the head of the gear housing, i.e. on the front end surface of the gear housing. The output shaft of the electric motor penetrates the gear housing and is inserted into the gear cavity, where it is connected to one of the gears or to the front end of one of the connecting shafts. When the electric motor is in operation, it drives one of the connecting shafts to rotate, which in turn drives the other two connecting shafts to rotate through the gears, thereby achieving the synchronous rotation of the first-stage and second-stage Roots rotor components and the screw rotor component, and thus achieving the three-stage vacuum pumping action (the first-stage Roots rotor component performs the first-stage vacuum pumping action in the first-stage Roots pump body cavity, the second-stage Roots rotor component performs the second-stage vacuum pumping action in the second-stage Roots pump body cavity, and the screw rotor component performs the third-stage vacuum pumping action in the screw pump body cavity).

[0096] The Roots pump is a two-stage Roots pump (a first-stage Roots pump body cavity, a first-stage Roots rotor component, a second-stage Roots pump body cavity, and a second-stage Roots rotor component, i.e. a two-stage Roots pump structure), which can achieve two-stage compression (also serving as a pressure booster) in a limited space, improve the vacuum degree and efficiency, reduce the space occupation, lower the energy consumption, and save costs. In addition, the heat generated during the vacuum compression of the gas by the first-stage Roots rotor component can be dissipated in advance, which can effectively prevent the temperature of the screw rotor component at the rear end from being too high, effectively prevent the damage of high temperature to the screw rotor component, and lower the temperature of the screw rotor component to prevent the coking of the carbon-hydrogen mixture (high temperature can easily cause coking and blockage of the carbon-hydrogen mixture), prevent the blockage of the screw rotor component from affecting the vacuum pumping, ensure the stability of the vacuum pumping, lower the temperature of the exhaust port, reduce the maintenance rate, and prolong the service life. When the two-stage Roots vacuum pump is used to process process media, the performance of the second-stage Roots pump body cavity and the second-stage Roots rotor component can form different compression ratios with the first-stage Roots pump body cavity and the first-stage Roots rotor component. Therefore, after calculating and designing a range of compression ratios, the process media discharged from the first-stage Roots pump body cavity can reach a higher and more stable temperature when entering the second-stage Roots pump body cavity, and the process media is further compressed in the second-stage Roots pump body cavity, which facilitates the subsequent pumping of the screw pump rotor component and further improves the vacuum degree. Since the intermediate connecting channel in the present embodiment is located at the bottom of the pump body, heat dissipation is facilitated.

[0097] In the present application, the dry screw pump is formed by two screw rotor components and a screw pump body cavity, which is a non-wet structure, i.e., no lubricating liquid is added inside. In this way, the screw pump is suitable for working in a high dust environment and reduces the occurrence of blockage. In order to reduce the occurrence of blockage, a two-stage Roots pump structure is adopted, i.e., two-stage compression and pressure increase are realized by using a Roots pump. When the gas with dust enters the first adjacent screw rotor components in the screw pump body cavity, the problem of blockage caused by the dust sticking to the lubricating liquid does not occur due to the absence of the lubricating liquid. In addition, the gas flow pressure entering the screw pump body cavity is high, and the dust discharge speed is also fast. Even if the problem of blockage occurs, the normal use time can be prolonged, and the cleaning and maintenance frequency can be reduced.

[0098] In the present application, the first bearing housing 25 and the second bearing housing 27 are respectively provided with cooling cavities (not shown in the figure) covering the first bearing cavity 29 and the second bearing cavity 31. The first bearing housing and the second bearing housing are respectively provided with a cooling medium inlet and a cooling medium outlet, which are connected to the corresponding cooling cavities.

[0099] In the present embodiment, the corresponding Roots rotor components and the Roots pump cavity do not contact each other, and the screw rotor components also do not contact the screw pump cavity. The connecting shaft only contacts the bearing and the pump body. During the rotation of the connecting shaft, the bearing generates high temperature. Due to the high temperature of the bearing, the pump body and the connecting shaft at the contact or connection position of the bearing may be slightly deformed. The mixed pump is a high-precision device. If the connecting shaft at the bearing position is slightly deformed, the corresponding first-stage Roots rotor component, the second-stage Roots rotor component, and the screw rotor component may rub against each other or the inner wall of the corresponding Roots pump cavity and the screw pump cavity. This not only affects the vacuum pumping effect, but also causes problems such as abnormal noise and wear. The maintenance rate is high, and the service life is shortened. Therefore, the cooling cavity is arranged outside the corresponding bearing cavity. The cooling medium is introduced into the cooling cavity through the cooling medium inlet, and the cooling medium is discharged from the cooling medium outlet. The circulation of the cooling medium in the cooling cavity cools the bearing cavity and the bearing, thereby preventing the above-mentioned problems, ensuring the stability of the connecting shaft, ensuring the assembly precision, and ensuring the stability and service life.

[0100] Further, as shown in FIGS. 4, 5, and 8, the outer wall of the pump body 1 is further provided with a notch communicating with the connecting channel 8. The pump body 1 is provided with a sealing component 35 sealing the notch.

[0101] In the present embodiment, the notch is arranged at the top of the pump body, and the sealing component is used to seal the top of the notch, so that the connecting channel can only communicate the second-stage Roots pump cavity and the screw pump cavity.

[0102] Preferably, in the embodiment, the connecting channel comprises a Roots connecting channel 36 and a screw connecting channel 37, the bottom of the Roots connecting channel 36 is communicated with the top of the secondary Roots pump body cavity 3, the top of the Roots connecting channel 36 is communicated with the top of the Roots pump body 26, and is arranged close to the screw pump body, that is, the top of the Roots connecting channel 36 is arranged close to the rear end of the Roots pump body; the bottom of the screw connecting channel 37 is communicated with the screw pump body cavity 4, and the top of the screw connecting channel 37 is communicated with the top of the second bearing shell 27, so that the top of the Roots connecting channel 36 and the top of the screw connecting channel 37 constitute the gap.

[0103] The sealing component 35 comprises a frame 38 and a sealing cover 39, the frame 38 is a hollow structure with an open top, the top of the frame 38 is provided with a connecting cavity 40, and the bottom surface of the frame 38 is provided with two through grooves 41 communicated with the connecting cavity 40, the two through grooves are respectively arranged opposite to the top of the Roots connecting channel and the top of the screw connecting channel, and the two ends of the frame are respectively mounted on the top of the Roots pump body and the second bearing shell, so that the two through grooves are respectively abutted against the top of the Roots connecting channel and the top of the screw connecting channel. In this way, the gas sent out from the Roots connecting channel can enter the connecting cavity through the corresponding through groove, and the sealing cover seals the top of the connecting cavity. In this way, the gas sent out from the secondary Roots pump body cavity enters the connecting cavity through the Roots connecting channel and the corresponding through groove, and then enters the screw connecting channel through the other through groove, and then enters the screw pump body cavity. In this way, the Roots connecting channel, the screw connecting channel and the connecting cavity constitute a complete connecting channel. In this way, the operator can directly open the sealing cover and the frame, so that the Roots connecting channel and the screw connecting channel are exposed. The operator can observe the internal situation through the corresponding Roots connecting channel and screw connecting channel. The operator can perform a simple maintenance without disassembling the pump body, and then perform targeted disassembly and maintenance without disassembling the pump body for maintenance, thereby improving the convenience of subsequent maintenance. In addition, during assembly and debugging of the Roots pump, the operator can observe the internal situation through the Roots connecting channel and the screw connecting channel, and insert a caliper into the internal situation to observe the assembly gap, thereby facilitating debugging.

[0104] Further, a filter screen can be arranged in the through groove to filter dust and other impurities in the Roots connecting channel and the screw connecting channel. In addition, the filter screen can prevent impurities from entering the corresponding secondary Roots pump body cavity or screw pump body cavity through the through groove during assembly.

[0105] Further, a fluid treatment component (not shown in the figure) can be detachably installed in the connecting passage at the gap. The fluid treatment component can be directly placed in the connecting cavity to treat the fluid flowing through the connecting passage. The fluid treatment component can be a filter, a caustic pack, a cooler or a heater, etc. The filter can be used to filter dust and other impurities flowing through the connecting passage. The caustic pack is used to adsorb water vapor to prevent the mixture of dust and water vapor from blocking the adjacent screw rotor component or the screw pump body cavity. If the temperature of the secondary Roots pump body cavity entering the screw pump body cavity is too high, a cooler can be provided to cool the gas to prevent the coking of the hydrocarbon mixture. If the temperature of the secondary Roots pump body cavity entering the screw pump body cavity is too low, the gas entering the screw pump body cavity is too cold, which can cause condensation, and the mixture of dust and condensate can block the screw pump body cavity. Therefore, a heater can be added to heat the gas to prevent condensation. Of course, there are other situations, and the selection can be made according to different construction environments. This has expandability, wider application range, can effectively ensure the vacuum pumping effect of the mixing pump, prolong the service life, and reduce the maintenance rate.

[0106] In the description of the present application, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0107] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, such as, the two are connected in a mechanical abutting or abutting manner through abutting, touching, etc., the two can also be directly hung or hung through an intermediate medium, or the two elements can be connected in an internal communication or mutual action relationship. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

Claims

1. A triaxial hybrid pump characterized by: The pump body and a connecting shaft rotatably installed in the pump body; The pump body is sequentially provided with a first-stage Roots pump cavity, a second-stage Roots pump cavity and a screw pump cavity along the axis of the connecting shaft; The pump body is provided with an air inlet, an air outlet, an intermediate connecting passage and a connecting passage, the air inlet connects the first-stage Roots pump cavity with the atmosphere, the air outlet connects the screw pump cavity with the atmosphere, the intermediate connecting passage connects the first-stage Roots pump cavity and the second-stage Roots pump cavity, and the connecting passage connects the second-stage Roots pump cavity and the screw pump cavity; The connecting shaft comprises an intermediate connecting shaft and first and second connecting shafts arranged in parallel on both sides of the intermediate connecting shaft; The first-stage Roots pump cavity is provided with two first-stage Roots rotor components in mesh with each other, the two first-stage Roots rotor components are respectively installed on the intermediate connecting shaft and the first connecting shaft, and when the two first-stage Roots rotor components rotate, fluid entering the air inlet is sent into the second-stage Roots pump cavity through the intermediate connecting passage; The second-stage Roots pump cavity is provided with two second-stage Roots rotor components in mesh with each other, the two second-stage Roots rotor components are respectively installed on the intermediate connecting shaft and the second connecting shaft, and when the two second-stage Roots rotor components rotate, fluid entering the intermediate connecting passage is sent into the screw pump cavity through the connecting passage; The screw pump cavity is provided with two screw rotor components in mesh with each other, the two screw rotor components are respectively installed on the intermediate connecting shaft and the first connecting shaft, and when the two screw rotor components rotate, fluid sent into the screw pump cavity through the connecting passage is discharged from the air outlet.

2. The triaxial hybrid pump of claim 1, wherein: The intermediate connecting shaft is inserted into the first-stage Roots pump cavity, the second-stage Roots pump cavity and the screw pump cavity; One end of the second connecting shaft is inserted into the second-stage Roots pump cavity; One end of the first connecting shaft is located in the screw pump cavity, and the other end is located in the first-stage Roots pump cavity.

3. The triaxial hybrid pump of claim 1, wherein: The pump body of the head of the first-stage Roots pump cavity is further provided with a gear cavity, the first-stage Roots pump cavity is arranged between the second-stage Roots pump cavity and the gear cavity, and the heads of the three connecting shafts are respectively inserted into the gear cavity; The head of each connecting shaft is respectively provided with a gear, and the gears of the heads of the first and second connecting shafts are respectively engaged with the gear of the head of the intermediate connecting shaft.

4. The triaxial hybrid pump of claim 3, wherein: The end of the intermediate connecting shaft sequentially passes through the first-stage Roots pump cavity and the second-stage Roots pump cavity and is inserted into the screw pump cavity, and the end of the intermediate connecting shaft and the end of the screw pump cavity have a spacing therebetween; And / or, the pump body beside the axis of the first-stage Roots pump cavity is provided with a second clearance hole connecting the gear cavity and the second-stage Roots pump cavity, the second connecting shaft is inserted into the second clearance hole, the end of the second connecting shaft is arranged in the second-stage Roots pump cavity and is rotatably connected with the pump body. And / or, the first displacement hole is arranged in the pump body beside the axis of the secondary Roots pump cavity and communicates the primary Roots pump cavity and the screw pump cavity, the middle part of the first connecting shaft is inserted into the first displacement hole, and the first connecting shaft on the two sides of the first displacement hole is respectively installed with the primary Roots rotor component and the screw rotor component.

5. The triaxial hybrid pump of claim 1, wherein: The pump body comprises a gear housing, a first bearing housing, a Roots pump body, a second bearing housing and a screw pump body which are sequentially and sealingly connected, The primary Roots pump cavity and the secondary Roots pump cavity are arranged in the Roots pump body, one end of the primary Roots pump cavity is communicated with the head of the Roots pump body, and one end of the secondary Roots pump cavity is communicated with the tail end of the Roots pump body; The first bearing housing and the second bearing housing are sealingly connected with the head and the tail end of the Roots pump body respectively; The screw pump cavity is arranged in the screw pump body, and one end of the screw pump cavity is communicated with the head of the screw pump cavity, and the head of the screw pump body is sealingly connected with the second bearing housing; The gear housing is provided with a gear cavity communicated with the tail end of the gear housing, and the tail end of the gear housing is sealingly connected with the first bearing housing.

6. The triaxial hybrid pump of claim 5, wherein: The first bearing cavity is arranged in the first bearing housing, and the heads of the three connecting shafts are respectively rotationally connected with the first bearing cavity through bearings; The second bearing cavity is arranged in the second bearing housing, and the tail end of the second connecting shaft is rotationally connected with the second bearing cavity through a bearing; The middle part of the intermediate connecting shaft and the first connecting shaft is respectively rotationally connected with the second bearing cavity through a bearing; And / or, the heads of the three connecting shafts are respectively inserted into the gear cavity through the corresponding bearings; The head of each connecting shaft is respectively provided with a gear, and the gears at the heads of the first connecting shaft and the second connecting shaft are respectively engaged with the gears on the two sides of the head of the intermediate connecting shaft.

7. The triaxial hybrid pump of claim 6, wherein: The first bearing housing and the second bearing housing are respectively provided with cooling cavities covering the first bearing cavity and the second bearing cavity, and the first bearing housing and the second bearing housing are respectively provided with a cooling medium inlet and a cooling medium outlet communicated with the corresponding cooling cavities.

8. The triaxial hybrid pump of claim 3 or 6, wherein: The head of the pump body is provided with a driving device configured to drive one of the gears or one of the connecting shafts to rotate.

9. The triaxial hybrid pump of claim 1, wherein: The screw rotor component is installed on the outer surface of the corresponding connecting shaft, and a micro gap is formed between the tail end of the screw rotor component and the tail end of the screw pump cavity; And / or, the primary Roots rotor component and the secondary Roots rotor component are in an integral structure with the corresponding connecting shaft.

10. The triaxial hybrid pump of claim 1, wherein: The outer wall of the pump body is further provided with a notch communicated with the connecting channel, and the pump body is provided with a sealing component sealing the notch; And / or, the fluid treatment component is detachably installed in the connecting channel at the notch.

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