CN110177947A - Multi-stage vacuum booster pump connector - Google Patents

Abstract

Disclose a kind of multistage vacuum pump with connection unit vacuum pump between grade.Include: coupling part between the first order for connector between the grade of multistage vacuum pump, limits the first part in the gap for the common rotor that the adjacent level for receiving by multistage vacuum pump is shared；And can coupling part between the second level that coupling part separates between the first order, coupling part limits the second part in the gap for the common rotor that the adjacent level for receiving by multistage vacuum pump is shared between the second level.In this way, provide a kind of connector, the assembled grade of assembled rotor and vacuum pump can be fixed together by the connector, the reason is that assembled rotor may be received in the removable part of connector, which can be assembled on assembled adjacent level again.This is maintained the mechanical integrity of rotor and adjacent level, while being still convenient for the assembling of multistage vacuum pump.

Description

Multi-stage vacuum booster pump coupling

technical field

The present invention relates to interstage couplings, vacuum pumps and methods for multistage vacuum booster pumps.

Background technique

Vacuum pumps are known. These pumps are often used as part of vacuum systems to evacuate devices. In addition, these pumps are used to evacuate manufacturing equipment used, for example, in semiconductor production. Instead of using a single pump to compress from vacuum to atmosphere in a single stage, it is known to provide multi-stage vacuum pumps in which each stage performs a portion of the total compression range required to transition from vacuum to atmospheric pressure.

Although such multi-stage vacuum pumps have advantages, they also have their own disadvantages. Accordingly, it would be desirable to provide an improved arrangement for a multi-stage vacuum pump.

Contents of the invention

According to a first aspect, there is provided a multi-stage vacuum pump comprising: a first pumping stage comprising a first integral stator; a second pumping stage comprising a second integral stator; and an interstage coupling unit for For coupling said first pumping stage and said second pumping stage, the coupling unit comprises a first interstage coupling defining a first portion of a space for receiving a common rotor shared by adjacent stages of a multistage vacuum pump portion, and a second interstage coupling portion separable from the first interstage coupling portion, the second interstage coupling portion defining a second portion for receiving a common rotor interspace shared by adjacent stages of the pump.

A first aspect recognizes that one problem with existing multi-stage vacuum pumps is that it is difficult to achieve a mechanically robust arrangement, which makes the pump complex and difficult to assemble. Therefore, the coupling unit is provided in the multi-stage vacuum pump. Coupling units can be used to connect different pumping stages of multistage vacuum pumps. The link may have a first interstage link portion. The first interstage coupling portion may define or provide a first portion or portion of a void or opening that may receive the rotor. The rotor may be shared by or extend into adjacent or adjacent stages of the vacuum pump. The coupling may also provide a second coupling portion. The second coupling part may be separate or separate from the first coupling part. The second coupling portion may define or provide a second portion or portion of the void or opening that receives the rotor. In this way, a coupling is provided which is able to fix together the assembled rotor and the assembled stages of the vacuum pump, since the assembled rotor can be received in a separable part of the coupling, which The separable parts can in turn be fitted to assembled adjacent stages. This allows the mechanical integrity of the rotor and adjacent stages to be maintained while still facilitating assembly of the multi-stage vacuum pump.

In one embodiment, the first interstage coupling part and the second interstage coupling part may be arranged in a coupled configuration in which the common rotor may be held by a gap and in a disconnected configuration in which the common rotor may be removed . Thus, the two coupling parts can be coupled or fixed together, as well as uncoupled or separated, in order to be able to hold or remove the rotor.

In one embodiment, the void is cylindrical and each of the first portion and the second portion defines a semi-cylindrical shape. Accordingly, the coupling portion may provide a substantially cylindrical void to receive a corresponding substantially cylindrical rotor.

In one embodiment, the first interstage coupling portion defines a respective first portion of a plurality of voids, each void for receiving a respective common rotor shared by adjacent stages of the multi-stage vacuum pump, and the second interstage coupling portion defines a plurality of voids. The corresponding second part of the gap. Thus, the coupling may provide more than one void, each coupling portion defining a portion of each of these voids. This enables more than one rotor to be received by the coupling portion.

In one embodiment, the first interstage coupling portion defines a first portion of the first and second coupling surfaces, and the second interstage coupling portion defines a second portion of the first and second coupling surfaces, and each A gap extends between the first coupling surface and the second coupling surface. Thus, the coupling piece can have coupling surfaces, and the interspace can extend through the coupling piece between these surfaces.

In one embodiment, each of the first coupling surface and the second coupling surface is configured to be received by a respective adjacent stage of the multi-stage vacuum pump. Accordingly, the coupling face may be dimensioned to attach to or couple with an adjacent stage of the vacuum pump to form one end of the housing of the adjacent stage.

In one embodiment, each of the first coupling surface and the second coupling surface is configured as a top plate to seal the ends of respective adjacent stages of the multi-stage vacuum pump. Thus, each face can act as a roof for an adjacent stage to substantially seal the periphery of that stage.

In one embodiment, the first coupling face defines an inlet port to receive exhaust gas from a first adjacent stage of the multi-stage vacuum pump, and the second coupling face defines an outlet port to deliver exhaust gas to the first adjacent stage of the multi-stage vacuum pump. Two adjacent stages, and the first interstage coupling portion and the second interstage coupling portion define a transfer conduit configured to fluidly couple the inlet port with the outlet port. Thus, one coupling face may provide the inlet aperture, while the other coupling face may define the outlet aperture. A conduit may extend between the inlet hole and the outlet hole. Inlet holes may receive exhaust from adjacent stages. Exhaust gas may be piped to an outlet port to route the exhaust gas to the inlet of an adjacent stage. Thus, the coupling itself facilitates the transfer of compressed gas from one stage to another without the need for additional piping.

In one embodiment, the inlet orifice is located fluidly downstream of a first adjacent stage of the multi-stage vacuum pump and the outlet orifice is located fluidly upstream of a second adjacent stage of the multi-stage vacuum pump. Thus, the inlet port can receive compressed gas or exhaust from the first stage and send it to the inlet of the second stage for further compression.

In one embodiment, one of the first and second portions of the first coupling surface defines an inlet aperture and the other of the first and second portions of the second coupling surface defines an outlet aperture. Thus, one part of the coupling may provide the inlet, while another part of the coupling may provide the outlet. This enables exhaust gas from one stage to be conveyed to the inlet of another stage due to the common rotation of the common rotor.

In one embodiment, one of the first and second portions of the first coupling surface defines an inlet aperture, and the other of the first and second portions of the first coupling surface defines a recirculation outlet aperture, and the first stage The interstage coupling portion and the second interstage coupling portion define a recirculation conduit configured to selectively fluidly couple the inlet port with the recirculation outlet port. Thus, one part of one face may have inlet holes, while another part of the face may have recirculation holes. The inlet port and the recirculation port may be connected by a recirculation conduit that selectively connects the inlet port with the recirculation outlet port to allow recirculation of fluid when required.

In one embodiment, one of the first and second portions of the second coupling surface defines an outlet aperture, and the other of the first and second portions of the second coupling surface defines a second recirculation outlet aperture, and the second The interstage coupling portion and the second interstage coupling portion define a second recirculation conduit configured to selectively fluidly couple the outlet port with the second recirculation outlet port. Thus, the other face can also have an outlet hole in one part and a second circulation hole in another part. The outlet hole and the second circulation hole may be connected by a second recirculation conduit. A second circulation conduit may selectively couple the outlet port with the second circulation port to recirculate fluid when desired.

In one embodiment, the recirculation conduit includes a pressure-actuated valve actuatable in response to a selected pressure differential between the inlet port and the recirculation outlet port to separate the inlet port from the recirculation outlet port. connect. Thus, when there is a predetermined pressure differential between the inlet port and the recirculation outlet port, the recirculation conduit can recirculate fluid to prevent damage to this stage of the vacuum pump.

In one embodiment, the second recirculation conduit includes a second pressure-actuated valve actuatable in response to a selected pressure differential between the outlet orifice and the second recirculation outlet to The outlet hole is coupled with a second recirculation outlet hole. Thus, when there is a predetermined pressure differential between the inlet port and the recirculation outlet port, the recirculation conduit can recirculate fluid to prevent damage to this stage of the vacuum pump.

According to a third aspect, there is provided a method comprising: in a first portion of the void defined by a first interstage coupling portion of an interstage coupling and by an interstage coupling separable from the first interstage coupling portion A common rotor shared by adjacent stages of the multi-stage vacuum pump is received in a second portion of the void defined by the second interstage coupling portion.

In one embodiment, the method includes receiving a common rotor in the first portion of the void when the first interstage coupling portion and the second interstage coupling portion are in the disengaged configuration.

In one embodiment, the method includes retaining the common rotor in the second portion of the void by arranging the first interstage coupling portion and the second interstage coupling portion in a coupled configuration.

In one embodiment, the void is cylindrical and each of the first portion and the second portion defines a semi-cylindrical shape.

In one embodiment, the method includes receiving a plurality of common rotors in respective first portions of the plurality of voids and respective second portions of the plurality of voids.

In one embodiment, the first interstage coupling portion defines a first portion of the first and second coupling surfaces, and the second interstage coupling portion defines a second portion of the first and second coupling surfaces, and each A gap extends between the first coupling surface and the second coupling surface.

In one embodiment, the method includes receiving a respective adjacent stage of the multi-stage vacuum pump through each of the first coupling surface and the second coupling surface.

In one embodiment, the method includes sealing the ends of respective adjacent stages of the multi-stage vacuum pump with each of the first coupling surface and the second coupling surface.

In one embodiment, the method includes receiving exhaust from a first adjacent stage of a multi-stage vacuum pump through an inlet hole in a first coupling face, fluidly coupling the inlet hole with the outlet hole using a transfer conduit, and connecting the An outlet hole in the face conveys the exhaust gas to the second adjacent stage of the multistage vacuum pump.

In one embodiment, the method includes positioning the inlet port fluidly downstream of a first adjacent stage of the multi-stage vacuum pump and positioning the outlet port fluidly upstream of a second adjacent stage of the multi-stage vacuum pump.

In one embodiment, one of the first and second portions of the first coupling surface defines an inlet aperture and the other of the first and second portions of the second coupling surface defines an outlet aperture.

In one embodiment, one of the first and second portions of the first coupling surface defines an inlet aperture, and the other of the first and second portions of the first coupling surface defines a recirculation outlet aperture, the first interstage The coupling portion and the second interstage coupling portion define a recirculation conduit, and the method includes selectively fluidly coupling the inlet port with the recirculation outlet port.

In one embodiment, one of the first and second portions of the second coupling surface defines an outlet aperture, the other of the first and second portions of the second coupling surface defines a second recirculation outlet aperture, and the first stage The interstage coupling portion and the second interstage coupling portion define a second recirculation conduit, and the method includes selectively fluidly coupling the outlet port with the second recirculation outlet port.

In one embodiment, the recirculation conduit includes a pressure-actuated valve, and the method includes coupling the inlet orifice with the recirculation outlet orifice in response to a selected pressure differential between the inlet orifice and the recirculation outlet orifice.

In one embodiment, the second recirculation conduit includes a second pressure-actuated valve, and the method includes connecting the outlet orifice to the second recirculation outlet in response to a selected pressure differential between the outlet orifice and the second recirculation outlet. hole connection.

Further particular and preferred aspects are set out in the appended independent and dependent claims. Features of the dependent claims may be combined with features of the independent claims as appropriate and in combinations other than those explicitly set out in the claims.

Where a device feature is described as being operable to provide a functionality, it should be understood that this includes device features that provide that functionality or are adapted or configured to provide that functionality.

Description of drawings

Embodiments of the invention will now be further described with reference to the accompanying drawings, in which:

Figures 1A and 1B illustrate a two-stage booster pump according to one embodiment;

Figure 2 is a perspective view of a rotor used in the two-stage booster pump of Figures 1A and 1B;

3 is a perspective view of a two-stage booster pump according to another embodiment;

Figure 4 is an exploded view of the pump of Figure 3;

Figure 5 shows an interstage coupling unit; and

Figure 6 shows an alternative configuration of the coupling unit.

Detailed ways

Before discussing the embodiments in more detail, an overview will first be provided. Embodiments provide arrangements that couple or link adjacent stages of a multi-stage vacuum pump. The coupling assembly located between two adjacent stages is a multi-part arrangement. The coupling assembly may be located outside the stator housing of an adjacent stage, or within one or more stator housings of an adjacent stage. The coupling assembly may be separated to enable the use of integral or one-piece rotors extending from one stage into the other. That is, rather than the rotor needing to be made from separate components and then assembled in situ, the rotor could be machined as a single item and the coupling assembled around the rotor. This provides a significantly stronger rotor which is less prone to failure. The coupling assembly may be separated to enable the use of a substantially unitary housing for each stage as well. That is, rather than each stage of housing needing to be made from separate components and then assembled, the housings can be machined as a single item and the couplings assembled to complete the housing. This provides a significantly stronger housing which is less prone to failure. This coupling acts as a roof between the stages and routes the exhaust from the upstream stage to the inlet of the downstream stage. This provides a simplified arrangement which avoids the need for external piping to transport gas between stages. Additionally, the coupling may house a recirculation valve that fluidly couples the outlet of a stage with its inlet in the presence of a high pressure differential to reduce damage.

two stage pump

1A and 1B illustrate a two-stage booster pump, generally 10 , according to one embodiment. The first pumping stage 20 is coupled to the second pumping stage 30 via an interstage coupling unit 40 . The first pumping stage 20 has a first stage inlet 20A and a first stage discharge 20B. The second pumping stage 30 has a second stage inlet 30A and a second stage outlet 30B.

Connector

The interstage coupling 40 is formed by a first portion 40A and a second portion 40B. The first portion 40A can be releasably secured to the second portion 40B. When placed together, the first portion 40A and the second portion 40B define a gallery 130 within the interstage coupling unit 40 through which gas may pass during operation of the vacuum pump. The interstage coupling unit 40 defines a cylindrical void 100 extending across the width of the interstage coupling unit 40 . The first portion 40A forms a first portion of the void 100 and the second portion 40B forms a second portion of the void 100 . The void 100 is divided to receive the one-piece rotor 50, which will be described in more detail below.

rotor

FIG. 2 is a perspective view of the rotor 50 . Rotor 50 is of the type used in positive displacement lobe pumps utilizing intermeshing pairs of lobes. Each rotor has a pair of cams formed symmetrically about the axis of rotation. Each cam 55 is defined by alternating tangential segments of a curve. As is well known, the curves may be of any suitable form, such as arcs of circles, or hypocycloidal and epicycloidal curves, or combinations thereof. In this example, the rotor 50 is integral, machined from a single metal element, and a cylindrical void 58 extends axially through the cam 55 to reduce mass.

A first axial end 60 of the shaft is received within a bearing provided by a top plate (not shown) of the first pumping stage 20 and extends from a first rotating blade portion 90A received within a stator of the first stage 20 . The intermediate axial portion 80 extends from the first rotating blade portion 90A and is received within the void 100 . The void 100 provides a tight fit on the surface of the intermediate axial portion 80, but does not act as a bearing. The second rotating blade portion 90B extends axially from the intermediate axial portion 80 and is received within the stator of the second stage 30 . The second axial end 70 extends axially from the second rotating blade portion 90B. The second axial end 70 is received by bearings in the top plate (not shown) of the second pumping stage 30 . The rotor 50 is machined as a single piece, with cutters forming the faces of a pair of cams 55 . The axial portions 60, 70, 80 are turned to form a first rotating blade portion 90A and a second rotating blade portion 90B.

It will be appreciated that a second rotor 50 (not shown) is received within a second void 100 which also extends across the width of the interstage coupling 40 but is spaced laterally from the first void 100 . The second rotor 50 is identical to the previous rotor 50 and is rotationally offset by 90° relative to the previous rotor 50 so that the two rotors 50 mesh synchronously.

pump stage stator

Returning to FIG. 1A , the first pumping stage 20 includes a one-piece stator 22 within which a chamber 24 is formed. The chamber 24 is sealed at one end by a top plate (not shown) and at the other end by an interstage coupling unit 40 . The one-piece stator 22 has a first inner surface 20C. In this embodiment, the first inner surface 20C is defined by equal semicircular portions coupled to straight segments extending tangentially between the semicircular portions to define a void/cavity for receiving the rotor 50 Room 24. However, embodiments may also define voids that are generally figure-eight-shaped in cross-section. The second pumping stage 30 includes a one-piece stator 32 forming a chamber 34 therein. The chamber 34 is sealed at one end by a top plate (not shown) and at the other end by an interstage coupling unit 40 . The one-piece stator 32 has a second inner surface 30C that defines a cavity 34 of generally figure eight cross-section that receives the rotor 50 . The presence of the integral stator 22 , 32 greatly increases the mechanical integrity and reduces the complexity of the first pumping stage 20 and the second pumping stage 30 . In an alternative embodiment, the top plate could also be integrally formed into each stator unit 22, 32 to form a bucket arrangement, which would further reduce the number of parts present.

The first rotating blade portion 90A of the rotor 50 operatively engages and follows the first inner surface 20C to compress gas provided from an upstream device or equipment at the first stage inlet 20A and to provide the compressed gas at the first stage discharge 20B . The compressed gas provided at the first stage discharge port 20B is passed through the inlet hole 120A formed in the first face 110A of the interstage coupling unit 40 . The first face 110A represents the boundary between the first pumping stage 20 and the gallery 130 . The compressed gas travels through a gallery 130 formed in the interstage coupling unit 40 and is discharged through an outlet hole 120B in the second face 110B of the interstage coupling unit 40 . The second face 110B represents the boundary between the gallery 130 and the second pumping stage 30 . The compressed gas exiting the outlet port 120B is received at the second stage inlet 30A. When the second rotating blade portion 90B of the rotor 50 engages and follows the second inner surface 30C, the compressed gas received at the second stage inlet 30A is further compressed by the second rotating blade portion 90B of the rotor 50, and the gas is discharged through the second stage. Exit 30B exits.

components

Assembly of the two-stage booster pump 10 is typically performed on a flip jig. The integral stator 22 of the first pumping stage 20 is fixed to the build jig. The top plate is attached to the stator 22 and the assembly is then rotated through 180 degrees.

Both rotors 50 are lowered into the first stage stator 22 . The first portion 40A and the second portion 40B of the interstage coupling 40 slide together on the intermediate axial portion 80 to retain the first rotating vane portion 90A within the first pumping stage 20 . The first part 40A and the second part 40B of the interstage coupling unit 40 are then typically doweled and bolted together. The assembled halves of the interstage coupling 40 are then attached to the integral stator 22 of the first pumping stage 20 .

The integral stator 32 of the second pumping stage 30 is now carefully lowered onto the second rotating blade part 90B and attached to the interstage coupling unit 40 .

The top plate is now attached to the integral stator 32 of the second stage pump 30 . The two rotors 50 are held by bearings in the two top plates.

Modified connectors

Figures 3 and 4 illustrate a two-stage booster pump, generally 10', according to one embodiment. The first pumping stage 20' is coupled with the second pumping stage 30' via an interstage coupling unit 40'. An interstage coupling 40' is located within the housing or stator 32' of the second pumping stage 30'. In this way, the interstage coupling 40' reuses the housing/stator 32' of the second pumping stage 30' as part of its construction, which provides a simplified construction by reducing the number of parts and by reducing the Quantity increases reliability. In Figure 4, the stator 32' of the second stage pump 30' has been removed to show the two halves of the interstage coupling 40'. In this embodiment, as shown more clearly in FIG. 5 , an axially extending curved web or skin 112 is provided along at least a portion of the outer perimeter of the plates 110A', 110B' to form a wall defining a gallery 130'. box section.

Returning to Figure 4, the interstage coupling 40' is formed by a first portion 40A' and a second portion 40B'. It can be seen that a pair of rotors 50 have been inserted into the inner bore of the first stage pump 20'. Furthermore, the second part 40B' has been inserted into place. The first part 40A' can be releasably secured to the second part 40B'. The first part 40A' and the second part 40B' can be fixed if desired. This can be done using grub screws which are inserted radially through the stator wall into flanges on the interstage coupling 40'. These screws can be sealed with sealant or PTFE tape.

The interstage coupling 40' defines a cylindrical void 100' extending across the width of the interstage coupling 40'. The first portion 40A forms a first portion of each void 100' and the second portion 40B' forms a second portion of each void 100'. Each void 100' is divided to receive a single-piece rotor 50.

The first stage pump 20' is formed by an integral chamber sealed at one end by a top plate (not shown) and at the other end by the combination of the second stage pump 30' and interstage coupling 40'. The second stage pump 30' is formed by an integral chamber sealed at one end by a top plate (not shown) and at the other end by the combination of the first stage pump 20' and the interstage coupling 40'.

In this embodiment, an interstage coupling 40' is located within the second stage pump 30'. The presence of the integral chamber greatly increases the mechanical integrity and reduces the complexity of the first stage pump 20' and the second stage pump 30'. Again, in an alternative, the top plate could be integrally formed with the stator of the second stage pump to provide a "bucket" type stator unit.

The first portion 40A' and the second portion 40B' are configured to reside within a bore in the stator 32' of the second stage pump 30'. The bore is slightly larger than the bore in which the rotor 50 rotates. This positions the interstage coupling 40' axially between this small step in the bore of the second stage and the stator 22' of the pump 20' of the first stage, which is connected to the bore of the rotor of the pump 20' of the second stage. The same as in the stage stator.

The first rotating vane portion 90A of the rotor 50 operatively engages and follows the first inner surface 20C' to compress gas provided at the first stage inlet 20A' from an upstream device or equipment and provided at the first stage discharge. compressed gas. The compressed gas provided at the discharge of the first stage passes through the inlet port 120A' coupled to the interstage coupling 40'. The compressed gas travels through a gallery 130' formed in the interstage coupling 40' and exits through an outlet port 120B' coupled with the interstage coupling 40'. The compressed gas exiting the outlet port 120B' is received at the second stage inlet. When the second rotating blade portion 90B of the rotor 50 engages and follows the inner surface of the second stage pump 30 ′, the compressed gas received at the inlet of the second stage is further compressed by the second rotating blade portion 90B of the rotor 50 and passed through the first The secondary discharge port 30B' discharges.

In an alternative embodiment as shown in Figure 6, axially extending spacer bars 114 are provided between the plates 110A", 110B", to form a gallery 130, the outer extent of which is defined by the stator 32 itself.

Thus, it can be seen that embodiments provide couplings coupling the stages of a multi-stage vacuum pump. That is to say, the couplings are located between the stages of the multistage vacuum pump. A multi-stage vacuum pump may have any number of stages, and one or more couplings may be located between any adjacent two of these stages, which need not be the first and second stages of the pump. The coupling has a pair of opposing outwardly facing coupling surfaces that are attached to adjacent stages. The coupling has an internal arrangement coupling an inlet formed in one coupling face with an outlet formed in the coupling face. The arrangement may have a valve that selectively couples the inlet to the outlet in response to a pressure differential between the inlet and the outlet. This coupling recirculates excess gas from the discharge of an adjacent stage back to the Inlet of this stage in order to reduce the strain on this stage of the pump. A variety of different pressure-actuated valve arrangements can be implemented, and some embodiments can reuse existing interstage transfer piping to provide a portion of the recirculator.

Thus, it can be seen that embodiments provide a two-stage supercharger with clamshell coupling units (transfer stages/transfer ports). Both the first and second stage supercharger rotors run in conventionally machined one-piece stators. The transfer ports that carry gas from the first stage to the second stage have a clamshell design consisting of two halves separated along the axes of the two rotors.

Embodiments recognize that conventional supercharger stators have a one-piece design. These are easy to machine and are very strong should the rotor fail. However, the embodiments also recognize that for a two-stage supercharger using three separate stator components (first stage stator, one-piece transfer stage, and second stage stator), the second stage supercharger rotor must be a separate parts to assemble the pump.

Embodiments also recognize that if a single piece rotor is used, the top and bottom clamshell stators can house the first and second stage rotors and form the transmission stage. However, these two components must be designed to be very rigid to avoid twisting during machining and assembly. They are also relatively difficult to machine due to their size.

Embodiments enable the use of a one-piece rotor and easily machined components. Both the first-stage supercharger rotor and the second-stage supercharger rotor run in a conventionally machined one-piece stator. The transfer stage transports gas from the first stage exhaust to the second stage inlet and has a clamshell design consisting of two halves separated along the axis of the two rotors.

Embodiments maintain the ease of manufacture and high strength of a one-piece stator, but utilize clamshells as transmission stages. This enables the assembly of a one-piece rotor design for a two-stage supercharger. Embodiments provide multi-stage pumps, particularly Roots-designed multi-stage pumps. Tighter tolerances can be maintained by using a clamshell transmission stage and a one-piece through-bore stator. The through-bore stator enables the use of rotors without the top end fillets that would normally be necessary for the fillets at the corners passing through the blind bore of the stator. Increased part accuracy and tighter tolerance control can enable a five-stage Roots design rather than a six- or seven-stage design that can still withstand the same low pressure.

In one embodiment, the clamshell half of the interstage coupling unit extends to the outside of the pump. In another embodiment, the clamshell half of the interstage coupling is received within one end of the stator component. Specifically, the clamshell halves may be housed within one of the two stators, preferably the shorter second stage stator.

While the illustrative embodiments of the present invention have been disclosed herein in detail with reference to the accompanying drawings, it is to be understood that the invention is not limited to the precise embodiments and that those skilled in the art can obtain the present invention without departing from the scope of the appended claims and their equivalents. Various changes and modifications are made within the scope of the present invention.

reference sign

two-stage booster pump 10; 10' first stage pump 20; 20' first level entrance 20A; 20A' first stage outlet 20B first inner surface 20C; 20C' second stage pump 30; 30' second level entrance 30A second stage outlet 30B; 30B' second inner surface 30C Interstage connectors 40; 40C first part 40A; 40A' the second part 40B; 40B' rotor 50, 50'; 50A; 50B first axial end 60 second axial end 70 middle axial part 80; 80A first rotating blade part 90A Second Rotary Blade Section 90B gap 100; 100' first side 110A second side 110B entrance hole 120A; 120A’; 120C exit hole 120B; 120B'; 120D; 120E corridor 130; 130' Transmission pipeline 140; 140'

Claims (12)

1. a kind of multistage vacuum pump, comprising:

First pump stage, including the first one-piece stator；

Second pump stage, including the second one-piece stator；And

Connection unit between grade, is used to couple first pump stage and second pump stage, connection unit includes:

Coupling part between the first order limits the first part for receiving the gap by the shared common rotor of the adjacent level pumped； With

Can coupling part between the second level that be separated with coupling part between the first order, coupling part, which limits, between the second level uses In the second part for receiving the gap by the shared common rotor of the adjacent level pumped.

2. vacuum pump according to claim 1, wherein second one-piece stator is configured to join between receiver stage in it Order member.

3. according to claim 1 or vacuum pump as claimed in claim 2, wherein coupling part limits first between the first order Coupling part limits the first conjunction plane and the second connection between conjunction plane and the first part and the second level of the second conjunction plane The second part in face, and each gap extends between first conjunction plane and second conjunction plane.

4. vacuum pump according to claim 3, wherein each of first conjunction plane and second conjunction plane It is configured as being received by the corresponding adjacent level of the multistage vacuum pump.

5. vacuum pump according to claim 3 or claim 4, wherein first conjunction plane and second connection Each of face is configured as top plate, to seal the end of the corresponding adjacent level of the multistage vacuum pump.

6. vacuum pump according to any one of claim 3 to 5, wherein first conjunction plane limits ingate, to connect The exhaust of the first adjacent level from the multistage vacuum pump is received, and second conjunction plane limits outlet opening, it will be described Exhaust is transported to the second adjacent level of the multistage vacuum pump, and joins between coupling part and the second level between the first order Socket part point limits transmission pipeline, and the transmission pipeline is configured as coupling the ingate with the outlet opening fluid.

7. vacuum pump according to claim 6, wherein the ingate is located at first phase of the multistage vacuum pump The downstream fluid of adjacent level, and the outlet opening is located at the fluid upstream of second adjacent level of the multistage vacuum pump.

8. the vacuum pump according to any one of claim 3 to 7, wherein the first part of first conjunction plane The ingate is limited with one in the second part, and the first part of second conjunction plane and described the Another in two parts limits the outlet opening.

9. the vacuum pump according to any one of claim 3 to 8, wherein the first part of first conjunction plane The ingate is limited with one in the second part, and the first part of first conjunction plane and described the Another in two parts limits recycling outlet opening, and connection part between coupling part and the second level between the first order Point recirculation conduit is limited, the recirculation conduit is configured as the ingate and the recycling outlet opening selectively Fluid connection.

10. the vacuum pump according to any one of claim 3 to 9, wherein the first part of second conjunction plane The outlet opening is limited with one in the second part, and the first part of second conjunction plane and described the Another in two parts limits the second recycling outlet opening, and joins between coupling part and the second level between the first order Socket part point limits the second recirculation conduit, and second recirculation conduit is configured as with described second following the outlet opening again Selectively fluid couples ring outlet opening.

11. according to claim 9 or vacuum pump described in any one of claim 10, wherein the recirculation conduit includes pressure actuated Valve, the pressure actuated valve can in response to the ingate and it is described recycling outlet opening between selected pressure difference and be activated with The ingate is coupled with the recycling outlet opening.

12. according to claim 10 or claim 11 described in vacuum pump, wherein second recirculation conduit include second Pressure actuated valve, the second pressure actuating valve can be in response to selected between the outlet opening and second recycling outlet Pressure difference and be activated with by the outlet opening with it is described second recycling outlet opening couple.