TWM571420U - Multi-stage vacuum booster pump connector - Google Patents

Abstract

This creation discloses a multi-segment vacuum pump having a section of inter-connected unit vacuum pump. An inter-segment connector for a multi-stage vacuum pump includes: a first inter-section connecting member defining one of a plurality of holes for receiving one of the common rotors shared by adjacent segments of the multi-stage vacuum pump And a second inter-section connecting member separable from the first inter-segment connecting member, the second inter-segment connecting member defining the common rotor for receiving the common rotor shared by the adjacent segments of the multi-segment vacuum pump The second part of one of the holes. In this manner, a connector is provided that enables one of the vacuum pump assembly rotors and the assembly section to be secured together because the assembly rotor can be received within the separable components of the connector, the separable components It can then be assembled to the adjacent segments of the assembly. This maintains the mechanical integrity of the rotor and the adjacent segments while still facilitating assembly of the multi-stage vacuum pump.

Description

Multi-stage vacuum booster pump connector

This creation relates to an inter-segment connector for a multi-stage vacuum booster pump, a vacuum pump and a method.

I know the vacuum pump. These pumps are commonly used as one of the vacuum systems for evacuation devices. In addition, such pumps are used to evacuate manufacturing equipment used, for example, to produce semiconductors. It is well known that instead of using a single pump to perform vacuum pressurization to atmospheric pressure in a single stage, a multi-stage vacuum pump is provided in which each section performs a portion of the entire pressurization process required to convert from vacuum to atmospheric pressure. Although these multi-stage vacuum pumps have their advantages, they have their own disadvantages. Therefore, it is desirable to provide an improved configuration of one of the multi-stage vacuum pumps.

According to a first aspect, a multi-stage vacuum pump is provided, comprising: a first pump section including a first unit stator; and a second pump section including a second unit stator; An inter-segment connection unit for connecting the first pump segment and the second pump segment, the connection unit comprising: a first inter-segment connection member defined to receive adjacent by the multi-segment vacuum pump a first portion of one of the holes of one of the common rotors; and a second inter-section connecting member separable from the first inter-segment connecting member, the second inter-segment connecting member being defined for receiving by the pump A second portion of the one of the holes of the common rotor shared by adjacent segments. The first aspect recognizes that the problem with multi-stage vacuum pumps is that it is difficult to achieve a mechanically stable configuration that complicates the assembly and makes assembly difficult. Therefore, a connecting unit is provided in the multi-stage vacuum pump. The connecting unit can be used to connect different pump segments of a multi-stage vacuum pump. The connector can have a first inter-segment connection component. The first inter-section connecting member can define or provide a first portion or component that can receive one of the holes or openings of a rotor. The rotor may be shared or extended by adjacent segments or adjacent segments of the vacuum pump into adjacent segments or adjacent segments of the vacuum pump. The connector can also provide a second connecting component. The second connecting member can be separated or disconnected from the first connecting member. The second attachment member can define or provide a second portion or component that receives one of the holes or openings of the rotor. In this manner, a connector is provided that enables one of the vacuum pump assembly rotors and the assembly section to be secured together because the assembly rotor can be received within the separable components of the connector, the separable components It can then be assembled to the adjacent segments of the assembly. This maintains the mechanical integrity of the rotor and the adjacent segments while still facilitating assembly of the multi-stage vacuum pump. In an embodiment, the first inter-segment connecting member and the second inter-segment connecting member may be configured such that the common rotor can be held by the hole in one of the connecting configurations and one of the common rotors can be removed. . Thus, the two connecting members can be attached or fixed together and disconnected or separated to enable the rotor to be retained or removed. In an embodiment, the hole is cylindrical and each of the first portion and the second portion defines a semi-cylindrical body. Thus, the connecting member can provide a generally cylindrical bore to receive a corresponding generally cylindrical rotor. In an embodiment, the first inter-segment connecting member defines a respective first portion of the plurality of holes, each of which is configured to receive a common rotor shared by one of the adjacent segments of the multi-segment vacuum pump, and the The inter-segment connection member defines a respective second portion of the plurality of holes. Thus, more than one hole may be provided by the connector, with each connecting member defining one of the components of each of the holes. This enables more than one rotor to be received by the connecting member. In one embodiment, the first inter-segment connecting member defines a first portion of the first connecting surface and the second connecting surface and the second inter-segment connecting member defines a first connecting surface and a second connecting portion And each hole extends between the first connecting surface and the second connecting surface. Thus, the connector can present a connection surface and the holes can extend between the faces through the connector. In one embodiment, each of the first attachment surface and the second attachment surface are configured to be received by respective adjacent segments of one of the plurality of vacuum pumps. Thus, the joining faces can be sized to attach to one of the adjacent sections of the vacuum pump or to an adjacent section of the vacuum pump to form one of the ends of one of the adjacent sections. In one embodiment, each of the first connecting surface and the second connecting surface is configured as a top plate to seal one end of the respective adjacent segments of the plurality of vacuum pumps. Thus, each face can act as a top plate for an adjacent segment to substantially seal one of the perimeters of the segment. In one embodiment, the first connecting surface defines an inlet aperture to receive an exhaust from a first adjacent section of the multi-segment vacuum pump and the second connection surface defines an outlet aperture to deliver the exhaust to One of the plurality of vacuum pumps is a second adjacent segment, and the first inter-segment connection member and the second inter-segment connection member define a transfer conduit configured to fluidly connect the inlet aperture to the outlet aperture. Thus, one of the attachment faces can provide an inlet aperture and the other attachment face can define an outlet aperture. A conduit can extend between the inlet aperture and the outlet aperture. The inlet aperture can receive the exhaust from an adjacent section. The exhaust gas may be delivered by the conduit to the outlet aperture to deliver the exhaust gas to an inlet of an adjacent section. Thus, the connector itself can facilitate the transfer of compressed gas from one section to another without the need for additional piping. In one embodiment, the inlet aperture is located downstream of the fluid of the first adjacent section of the multi-section vacuum pump and the outlet aperture is positioned upstream of the fluid of the second adjacent section of the multi-section vacuum pump. Thus, the inlet aperture can receive compressed gas or exhaust from the first section and deliver it to one of the inlets of the second section for further compression. In one embodiment, one of the first portion and the second portion of the first connection surface defines the inlet aperture and the other of the first portion and the second portion of the second connection surface define the exit aperture . Thus, one of the portions of the connector can provide an inlet and another portion of the connector can provide an outlet. This allows the exhaust from one section to be transferred to the inlet of the other section due to the common rotation of the common rotor. In one embodiment, one of the first portion and the second portion of the first connection surface defines the inlet aperture and the other of the first portion and the second portion of the first connection surface define a recirculation outlet A bore, and the first inter-section connecting member and the second inter-segment connecting member define a recirculation conduit configured to selectively fluidly connect the inlet aperture to the recirculation outlet aperture. Thus, one of the sides may have the inlet aperture and the other portion of the face may have a recirculation aperture. The inlet port and the recirculation port may be selectively connected to the inlet port to be connected to a recirculation conduit of the circulation outlet port to allow recirculation of fluid as needed. In one embodiment, one of the first portion and the second portion of the second connecting surface defines the exit aperture and the other of the first portion and the second portion of the second connecting surface define a second The outlet port is recirculated, and the first inter-segment connection member and the second inter-segment connection member define a second recirculation conduit configured to selectively fluidly connect the outlet port to the second recirculation outlet port. Therefore, the other side may have the outlet hole in one portion and a secondary circulation hole in the other portion. The outlet port and the secondary circulation hole may be connected by a second recirculation conduit. The secondary circulation conduit selectively connects the outlet orifice to the secondary circulation orifice to recirculate fluid as needed. In one embodiment, the recirculation conduit includes a pressure actuated valve actuatable to connect the inlet port to the recirculation in response to a selected pressure differential between the inlet port and the recirculation outlet port Exit hole. Thus, when a predetermined pressure differential exists between the inlet aperture and the recirculation outlet aperture, the recirculation conduit can recirculate fluid to prevent damage to the section of the vacuum pump. In one embodiment, the second recirculation conduit includes a second pressure actuated valve actuatable to connect the outlet in response to a selected pressure differential between the outlet aperture and the second recirculation outlet a hole and the second recirculation outlet port. Thus, when a predetermined pressure differential exists between the inlet aperture and the recirculation outlet aperture, the recirculation conduit can recirculate fluid to prevent damage to the section of the vacuum pump. Further specific and preferred aspects are set forth in the accompanying independent and affiliated technical solutions. The features of the subsidiary technical solutions may be combined with the features of the independent technical solutions, depending on the circumstances and in addition to the combinations explicitly stated in the technical solutions. Although a device feature is described as being operable to provide a function, it should be understood that this includes a device feature that provides the functionality or is adapted or configured to provide that functionality.

An overview will first be provided prior to discussing the embodiments in more detail. Embodiments provide for configuring or joining one of the adjacent segments of a multi-segment vacuum pump. A connection assembly positioned between two adjacent segments is a multi-component configuration. The joint assembly can be positioned outside of the stator casing of an adjacent segment or within one or more stator casings of adjacent segments. The connection assembly can be separated to enable the use of a single or single piece rotor extending from one segment to another. That is, instead of having the rotor made of a separate assembly and then assembled in situ, the rotor can be machined into a single product and the connector assembled around the rotor. This provides a significantly more stable rotor that is less prone to failure. The attachment assembly can be separated to also achieve a substantially unitary outer casing for use by the segments. That is, instead of having the outer casings of the segments made of separate components and then assembled, the outer casing can be machined into a single product and the connector assembled to complete the outer casing. This provides a significantly more robust enclosure that is less prone to failure. The connector acts as a top plate between the segments and delivers the exhaust of an upstream section to the inlet of a downstream section. This provides a simplified configuration that avoids the need for an external pipe to transfer gas between the segments. In addition, the connector can house a recirculation valve that fluidly connects a section of the outlet to its inlet to reduce damage in the presence of a high pressure differential. Two-Stage Pump FIG. 1A and FIG. 1B illustrate a two-stage booster pump (generally designated 10) in accordance with an embodiment. A first pump section 20 is connected to a second pump section 30 via an inter-segment connection unit 40. The first pump section 20 has a first section inlet 20A and a first section outlet port 20B. The second pump section 30 has a second section inlet 30A and a second section discharge port 30B. Connector The inter-segment connector 40 is formed by a first portion 40A and a second portion 40B. The first portion 40A is releasably secured to the second portion 40B. The first portion 40A and the second portion 40B define a gallery 130 within the inter-segment connection unit 40 when joined together, and the gas can pass through the gallery 130 during operation of the vacuum pump. The inter-segment connection unit 40 defines a cylindrical hole 100 that extends through one of the widths of the inter-segment connection unit 40. The first portion 40A forms a first portion of the aperture 100 and the second portion 40B forms a second portion of the aperture 100. The hole 100 can be separated to receive a one-piece rotor 50, as will now be described in more detail. Rotor Figure 2 is a perspective view of one of the rotors 50. The rotor 50 is of the type used to utilize one of the positive displacement vane pumps of the meshing vane pair. Each rotor has a pair of lobes symmetrically formed about a rotatable shaft (shaft). Each leaflet 55 is defined by an alternating tangential section of the curve. The curve can have any suitable form, such as a generally known arc or an inner and outer cycloid or a combination of these. In this example, rotor 50 is a single body machined from a single metal component and cylindrical bore 58 extends axially through vane 55 to reduce mass. One of the first axial ends 60 of the shaft is received in one of the bearings provided by one of the first pump segments 20 (not shown) and self-accepting one of the first rotating blades in one of the first segments 20 Part 90A extends. An intermediate axial portion 80 extends from the first rotating blade portion 90A and is received within the bore 100. The bore 100 provides a tight fit on the surface of the intermediate axial portion 80 but does not act as a bearing. A second rotating blade portion 90B extends axially from the intermediate axial portion 80 and is received within one of the stators of the second segment 30. A second axial end 70 extends axially from the second rotating blade portion 90B. The second axial end 70 is received by one of the bearings of one of the second pump segments 30 (not shown). The rotor 50 is machined into a single piece and the cutter forms the surface of the pair of vanes 55. The axial portions 60, 70, 80 are rotated 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 in a second aperture 100 that also extends through the width of the inter-segment connector 40 but is laterally spaced from the first aperture 100. The second rotor 50 is identical to the aforementioned rotor 50 and is rotated by 90° from the aforementioned rotor such that the two rotors 50 are synchronously engaged. The pump section stator returns to Figure 1A, and the first pump section 20 includes a single stator 22 in which a chamber 24 is formed. One end of the chamber 24 is sealed by a top plate (not shown) and the other end is sealed by an inter-segment connection unit 40. The unitary stator 22 has a first inner surface 20C. In this embodiment, the first inner surface 20C is defined by equal semi-circular portions that are connected to the straight sections that extend tangentially between the semi-circular portions to define a hole/cavity that receives one of the rotors 50. Room 24. However, embodiments can also define a generally eight-shaped cross-sectional face hole. The second pump section 30 includes a single stator 32 in which a chamber 34 is formed. One end of the chamber 34 is sealed by a top plate (not shown) and the other end is sealed by an inter-segment connection unit 40. The unitary stator 32 has a second inner surface 30C that defines a cross-sectional chamber 34 that receives a slightly 8-shaped shape of the rotor 50. The presence of the unitary stators 22, 32 greatly enhances mechanical integrity and reduces the complexity of the first and second pump sections 20, 30. In an alternate embodiment, the top plate may also be integrated into each of the stator units 22, 32 to form a barrel configuration, which will further reduce the number of components present. The first rotating blade portion 90A of the rotor 50, 50' engages in operation and follows the first inner surface 20C to compress the gas provided by an upstream device or device at a first stage inlet 20A and at a first stage discharge port Compressed gas is supplied at 20B. The compressed gas supplied at the first stage discharge port 20B passes through one of the inlet holes 120A formed in one of the first faces 110A of the inter-segment connection unit 40. The first face 110A represents a boundary between the first pump section 20 and the gallery 130. The compressed gas travels through the gallery 130 formed in the inter-segment connection unit 40 and exits through one of the outlet holes 120B in one of the second faces 110B of the inter-segment connection unit 40. The second face 110B represents a boundary between the gallery 130 and the second pump segment 30. The compressed gas discharged from the outlet port 120B is received at a second section 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 passes through a second segment. The discharge port 30B is discharged. Assembly The assembly of the two-stage booster pump 10 is typically performed on a flipping fixture. The single stator 22 of the first pump section 20 is fixed to the build fixture. The top plate is attached to the stator 22 and then the assembly is rotated 180 degrees. The two rotors 50 are lowered into the first stage stator 22. The first portion 40A and the second portion 40B of the inter-segment connector 40 are slid together on the intermediate axial portion 80 to retain the first rotating blade portion 90A within the first pumping section 20. Next, the first portion 40A and the second portion 40B of the inter-segment connection unit 40 are typically connected and bolted together by dowels. Next, the assembly half of the inter-segment connector 40 is attached to the unitary stator 22 of the first pump section 20. The single stator 32 of the second pumping section 30 is now carefully lowered onto the second rotating blade portion 90B and attached to the inter-segment connecting unit 40. A top plate is now attached to the single stator 32 of the second stage 30. The two rotors 50 are held by bearings in the two top plates. Modified Connector FIGS. 3 and 4 illustrate a two-stage booster pump (generally indicated at 10') in accordance with an embodiment. A first pump section 20' is coupled to a second pump section 30' via an inter-segment connection unit 40'. The inter-segment connector 40' is positioned within one of the outer casings or stators 32' of the second pumping section 30'. Thus, the inter-segment connector 40' uses the outer casing/stator 32' of the second pumping section 30' as a component of its structure, which provides a simplified construction by reducing the number of components and is improved by reducing the number of external seals. reliability. In Figure 4, the stator 32' of the second stage 30' has been removed to show the two halves of the inter-segment connector 40'. In this embodiment, as shown more clearly in FIG. 5, at least a portion of the outer periphery of one of the panels 110A', 110B' provides an axially extending curved web or outer panel 112 to define a defined gallery 130'. A box section. Returning to Figure 4, the inter-segment connector 40' is formed by a first portion 40A' and a second portion 40B'. As can be seen, a pair of rotors 50 are inserted into the bores of the first section of the pump 20'. Further, the second portion 40B' is inserted into position. The first portion 40A' is releasably secured to the second portion 40B'. The first portion 40A' and the second portion 40B' may be fixed as needed. This can be accomplished using a headless screw that is inserted radially through the stator wall into the flange of the inter-segment connector 40'. These screws can be sealed with a sealant or PTFE tape. The inter-segment connector 40' defines a cylindrical bore 100' that extends through the width of the inter-segment connector 40'. The first portion 40A' forms a first portion of each of the holes 100' and the second portion 40B' forms a second portion of each of the holes 100'. Each of the holes 100' can be separated to receive a one-piece rotor 50. The first stage pump 20' is formed by a single chamber, one end of which is sealed by a top plate (not shown) and the other end is made up of one of the second stage 30' and the inter-segment connector 40' Combination seal. The second stage pump 30' is formed by a single chamber, one end of which is sealed by a top plate (not shown) and the other end is made up of one of the first stage pump 20' and the inter-segment connector 40' Combination seal. In this embodiment, the inter-segment connector 40' is positioned within the second segment of the pump 30'. The presence of a single chamber greatly enhances mechanical integrity and reduces the complexity of the first stage 20' and the second stage 30'. Additionally, in an alternative, the top plate can be integrated 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 be positioned within an inner bore of the stator 32' of the second length of the pump 30'. The inner bore is slightly larger than the inner bore in which the rotor 50 rotates. This axially positions the inter-segment connector 40' between the small stage of the second section bore and the stator 22' of the first section of the pump 20'. The rotor bore of the first section of the pump 20' is the same as The inner bore of the rotor in the second stage stator. The first rotating blade portion 90A of the rotor 50 engages in operation and follows a first inner surface 20C' to compress the gas provided by an upstream device or device at a first stage inlet 20A' and at a first stage discharge port Compressed gas is supplied at the site. The compressed gas supplied at the first stage discharge port is connected to one of the inlet holes 120A' through the inter-segment connector 40'. The compressed gas travels through one of the corridors 130' formed in the inter-segment connector 40' and exits through one of the outlet holes 120B' connected to the inter-segment connector 40'. The compressed gas discharged from the outlet port 120B' is received at a second stage inlet. When the second rotating blade portion 90B of the rotor 50 engages and follows an inner surface of the second segment of the pump 30', the compressed gas received at the second segment inlet is further compressed by the second rotating blade portion 90B of the rotor 50 and via a second The section discharge port 30B' is discharged. In an alternate embodiment, as depicted in Figure 6, axially extending spacer bars 114 are provided between the plates 110A", 110B" to form a gallery 130 that is defined by the stator 32 itself. Thus, it can be seen that the embodiment provides one of a plurality of segments connected to a multi-segment vacuum pump. That is, the connector is located between segments of a multi-segment vacuum pump. The multi-segment vacuum pump can have any number of segments and one or more connectors can be located between any two neighbors of the segments (which need not be the first and second segments of the pump). The connector has an opposing connecting face that is attached to one of the adjacent segments. The connector has an internal configuration that connects one of the inlets formed in one of the joint faces and one of the outlets formed in the joint face. The arrangement can have a valve that selectively connects the inlet to the outlet in response to a pressure differential between the inlet and the outlet. The connector recirculates excess gas from one of the adjacent sections to the inlet of the section to reduce strain on the section of the pump. A so-called "gas discharge" should occur by introducing excess gas into the section. In the discharge port, for example, it may occur when the pump is vented. A variety of different pressure actuated valve configurations can be implemented, and some embodiments can reuse an inter-segment transfer conduit to provide a portion of the recirculator. Thus, it can be seen that the embodiment provides a two-stage supercharger having a clamshell connection unit (transfer section/transfer port). Both the first stage supercharged rotor and the second stage supercharged rotor operate in a conventionally machined one-piece stator. The transfer port for transferring the gas from the first section to the second section has a clamshell design consisting of two halves separated along the axis of the two rotors. Embodiments recognize that conventional supercharged stators have a one-piece design. These stators are easy to machine and are very robust in the event of a rotor failure. However, the embodiment also recognizes that since a two-stage supercharger uses three separate stator assemblies (a first stage stator, a one-piece transfer section and a second stage stator), the second stage booster rotor will have to To separate the components to assemble the pump. Embodiments also recognize that if a one-piece rotor is used, the top and bottom clamshell stators can receive the first and second rotors and form a transfer section. However, these two components will have to be designed to be very hard to avoid deformation during processing and assembly. These components are also relatively difficult to machine due to their size. Embodiments are capable of using a one-piece rotor and easy-to-machine assembly. Both the first stage supercharged rotor and the second stage supercharged rotor operate in a conventionally machined one-piece stator. The transfer section diverts gas from the first stage exhaust outlet to the second section inlet and has a clamshell design consisting of two halves separated along the axis of the two rotors. The embodiment maintains the ease of manufacture and high strength of the one-piece stator, but uses a clamshell for the transfer section. This achieves the assembly of a one-piece rotor design for a two-stage supercharger. The embodiment provides a multi-segment pump, in particular, a multi-segment pump root design. Due to the use of a clamshell transfer section and a one-piece through-hole stator, tight tolerances can be maintained. Through-hole stators can use rotors with no tip radius, and tip radius is typically required to eliminate the radius of the corners of the stator blind holes. The improved accuracy of the components and tight tolerance control allow for a five-segment design rather than a six- or seven-segment design that will still withstand the same low voltage. In an embodiment, the clamshell half of the inter-segment connection unit extends to the exterior of the pump. In another embodiment, the clamshell half of the inter-segment connector is received in one of the ends of a sub-assembly. In particular, the clamshell half may be housed in one of the two stators, preferably in the shorter second stage stator. Although the present embodiments of the present invention have been disclosed in detail herein with reference to the drawings, it is understood that the invention is not limited to the precise embodiments and the skilled artisan can Various changes and modifications of the embodiments are made in the context of the invention.

10‧‧‧Two-stage supercharged pump

10'‧‧‧Two-stage supercharged pump

20‧‧‧The first wave of the section

20'‧‧‧The first group of Pu

20A‧‧‧ first paragraph entrance

20A'‧‧‧ first paragraph entrance

20B‧‧‧ first stage discharge

20C‧‧‧First inner surface

20C'‧‧‧ first inner surface

22‧‧‧First stage stator

22'‧‧‧ Stator

24‧‧‧ chamber

30‧‧‧Second section

30'‧‧‧Second section

30A‧‧‧ second paragraph entrance

30B‧‧‧Second section discharge

30B'‧‧‧Second section discharge

30C‧‧‧Second inner surface

32‧‧‧ Stator

32'‧‧‧ Stator

34‧‧‧ chamber

40‧‧‧Inter-segment connection unit/inter-segment connector

40'‧‧‧Interconnection unit/inter-segment connector

40A‧‧‧Part 1

40A'‧‧‧Part 1

40B‧‧‧Part II

40B'‧‧‧ Part II

50‧‧‧Rotor

50'‧‧‧Rotor

55‧‧‧leaf

58‧‧‧ hole

60‧‧‧First axial end

70‧‧‧second axial end

80‧‧‧ intermediate axial part

90A‧‧‧First rotating blade section

90B‧‧‧Second rotating blade section

100‧‧‧ holes

100'‧‧‧ hole

110A‧‧‧ first side

110A'‧‧‧ board

110A''‧‧‧ board

110B‧‧‧ second side

110B'‧‧‧ board

110B''‧‧‧ board

112‧‧‧Axial extension curved web/outer plate

114‧‧‧ spacer

120A‧‧‧ entrance hole

120A'‧‧‧ entrance hole

120B‧‧‧Exit hole

120B'‧‧‧Exit hole

130‧‧‧ Corridor

130'‧‧‧ Corridor

Embodiments of the present invention will now be further described with reference to the accompanying drawings in which: FIG. 1A and FIG. 1B illustrate a two-stage booster pump according to an embodiment; FIG. 2 is a two-stage booster pump for FIG. 1A and FIG. 1 is a perspective view of one of the rotors; FIG. 3 is a perspective view of one of the two-stage booster pumps according to another embodiment; FIG. 4 is an exploded view of the pump of FIG. 3; And Figure 6 illustrates an alternative configuration of the connection unit.

Claims (12)

A multi-stage vacuum pump comprising: a first pump section including a first unit stator; a second pump section including a second unit stator; and an inter-segment connection unit for Connecting the first pump segment and the second pump segment, the connecting unit comprising: a first inter-segment connecting member defining a hole for receiving one of the common rotors shared by adjacent segments of the pump a first portion; and a second inter-section connecting member separable from the first inter-segment connecting member, the second inter-segment connecting member defining a common rotor for receiving an adjacent segment shared by the pump The second part of one of the holes. The vacuum pump of claim 1, wherein the second unitary stator is configured to receive the inter-segment connection unit therein. The vacuum pump of claim 1 or 2, wherein the first inter-section connecting member defines a first portion of the first connecting surface and the second connecting surface and the second inter-segment connecting member defines the first connecting surface and the first a second portion of the two connecting faces, and each of the holes extends between the first connecting face and the second connecting face. The vacuum pump of claim 3, wherein each of the first connection surface and the second connection surface is configured to be received by a respective adjacent one of the plurality of vacuum pumps. The vacuum pump of claim 3, wherein each of the first connection surface and the second connection surface is configured as a top plate to seal one end of the respective adjacent segments of the plurality of vacuum pumps. The vacuum pump of claim 3, wherein the first connecting surface defines an inlet aperture to receive an exhaust from a first adjacent segment of the multi-segment vacuum pump and the second connection surface defines an exit aperture to define Exhaust gas is delivered to one of the second adjacent segments of the multi-stage vacuum pump, and the first inter-segment connecting member and the second inter-segment connecting member are configured to fluidly connect the inlet port to the one of the outlet holes catheter. The vacuum pump of claim 6, wherein the inlet aperture is located downstream of the fluid of the first adjacent section of the multi-section vacuum pump and the outlet aperture is positioned at the second adjacent section of the multi-section vacuum pump Upstream. The vacuum pump of claim 3, wherein the first portion of the first connection surface and one of the second portions define the inlet aperture and the first portion of the second connection surface and the other of the second portion Define the exit hole. The vacuum pump of claim 3, wherein the first portion of the first connection surface and one of the second portions define the inlet aperture and the first portion of the first connection surface and the other of the second portion A recirculation exit aperture is defined, and the first inter-segment connection component and the second inter-segment connection component define a recirculation conduit configured to selectively fluidly connect the inlet aperture to the recirculation exit aperture. The vacuum pump of claim 3, wherein the first portion of the second connection surface and one of the second portions define the outlet aperture and the first portion of the second connection surface and the other of the second portion Defining a second recirculation outlet aperture, and the first inter-segment connection component and the second inter-segment connection component are configured to selectively fluidly connect the outlet aperture to the second recirculation outlet aperture Recirculation conduit. The vacuum pump of claim 9, wherein the recirculation conduit includes a pressure actuated valve actuatable in response to a selected pressure differential between the inlet aperture and the recirculation outlet aperture The inlet port and the recirculation outlet port are connected. The vacuum pump of claim 10, wherein the second recirculation conduit includes a second pressure actuated valve actuatable in response to the outlet aperture and the second recirculation outlet A selected pressure difference therebetween connects the outlet orifice to the second recirculation outlet orifice.