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EP-4739886-A1 - INTERSTAGE PLATE FOR A VACUUM PUMP

EP4739886A1EP 4739886 A1EP4739886 A1EP 4739886A1EP-4739886-A1

Abstract

An interstage plate system comprising: a first plate portion comprising a first recess in a first mating surface of the first plate portion; and a second plate portion comprising a second recess in a second mating surface of the second plate portion; wherein the first plate portion and the second plate portion are configured to be coupled together so as to form an interstage plate for a vacuum pump and such that: the first mating surface and the second mating surface abut; and the first recess and the second recess are opposing, contiguous recesses which together form an aperture through the interstage plate.

Inventors

  • NORTH, MICHAEL HENRY

Assignees

  • Edwards Limited

Dates

Publication Date
20260513
Application Date
20240515

Claims (15)

  1. 1. An interstage plate system comprising: a first plate portion comprising a first recess in a first mating surface of the first plate portion; and a second plate portion comprising a second recess in a second mating surface of the second plate portion; wherein the first plate portion further comprises a third recess in the first mating surface; and the second plate portion further comprises a fourth recess in the second mating surface; and the first plate portion and the second plate portion are configured to be coupled together so as to form an interstage plate for a vacuum pump and such that: the first mating surface and the second mating surface abut; the first recess and the second recess are opposing, contiguous recesses which together form an aperture through the interstage plate; and the third recess and the fourth recess are opposing, contiguous recesses which together form a further aperture through the interstage plate; and wherein the first plate portion and the second plate portion are fixedly attached together by fasteners passing through a respective pair of fastener holes extending through the first and second mating surfaces.
  2. 2. The interstage plate system of claim 1 , wherein: the first plate portion comprises two first dowel holes that extend into the first plate portion from the first mating surface; and the second plate portion comprises two second dowel holes that extend into the second plate portion from the second mating surface; and the system further comprises: two dowels located in a respective pair of the first and second dowel holes.
  3. 3. The interstage plate system of any preceding claim, wherein the first plate portion comprises a first outer surface opposite to the first mating surface and a first tab extending from the first outer surface, the first tab including a first tab fastener hole passing through the first tab from a first side of the first plate portion to a second side of the first plate portion.
  4. 4. The interstage plate system of any preceding claim, wherein the second plate portion comprises a second outer surface opposite to the second mating surface and a second tab and a third tab extending from the second outer surface, each of the second and third tabs including a respective second tab fastener hole passing through the respective one of the second and third tab from a first side of the second plate portion to a second side of the second plate portion.
  5. 5. The interstage plate system of claim 4, wherein the second plate portion comprises a fifth recess formed in a central portion of the second outer surface between the second tab and the third tab.
  6. 6. The interstage plate system of any of claims 1 to 4, wherein the second plate portion comprises a fifth recess in a surface of the second plate portion other than the second mating surface.
  7. 7. A rotor assembly for a vacuum pump, the rotor assembly comprising: an interstage plate formed by the interstage plate system of any preceding claim; a first rotor; a second rotor; and a first shaft; wherein the first rotor and the second rotor are coaxially aligned and fixed to the first shaft; the first shaft passes through the aperture in the interstage plate formed by the first and second recesses; and the interstage plate is disposed between the first rotor and the second rotor; and a third rotor; a fourth rotor; and a second shaft; wherein the third rotor and the fourth rotor are coaxially aligned and fixed to the second shaft; the second shaft passes through the further aperture in the interstage plate formed by the third and fourth recesses; the interstage plate is disposed between the third rotor and the fourth rotor; and the second shaft is substantially parallel with the first shaft.
  8. 8. The rotor assembly of claim 7, wherein the first rotor and the third rotor are a Roots rotor and the second rotor and the fourth rotor are a screw rotor.
  9. 9. The rotor assembly of claim 7 or 8, wherein the first rotor and the third rotor are intermeshed, and the second rotor and the fourth rotor are intermeshed.
  10. 10. A vacuum pump comprising: a stator having a pumping chamber; and the rotor assembly of any of claims 7 to 9 at least partially disposed within the pumping chamber.
  11. 11 . The vacuum pump of claim 10, wherein: the stator comprises a plate seat formed from one or more walls of the pumping chamber, the plate seat being formed between a first pumping stage of the vacuum pump and a second pumping stage of the vacuum pump; and the interstage plate engages and is fixedly attached to the plate seat.
  12. 12. The vacuum pump of any of claims 10 or 11 , wherein the interstage plate is formed from the same material as the material from which the stator is formed.
  13. 13. A method of assembling a rotor assembly, the method comprising: providing a first rotor shaft assembly comprising: a first rotor; a second rotor; and a first shaft; wherein the first rotor and the second rotor are coaxially aligned and fixed to the first shaft; providing a second rotor shaft assembly comprising: a third rotor; a fourth rotor; and a second shaft; the third rotor and the fourth rotor are coaxially aligned and fixed to the second shaft; providing an interstage plate system comprising: a first plate portion comprising a first recess and a third recess in a first mating surface of the first plate portion; and a second plate portion comprising a second recess and a fourth recess in a second mating surface of the second plate portion; and clamping the first plate portion and the second plate portion about the first and second shafts such that: the first plate portion and the second plate portion together form an interstage plate disposed between the first rotor and the second rotor and between the third and fourth rotor; the first recess and the second recess are opposing, contiguous recesses which together form a first aperture through the interstage plate; the third recess and the fourth recess are opposing, contiguous recesses which together form a second aperture through the interstage plate; the first shaft passes through the first aperture; and the second shaft passes through the second aperture; wherein the step of clamping comprises: abutting the first and second mating surfaces; and fastening the first plate portion to the second plate portion using fasteners passing through a respective pair of fastener holes extending through the first and second mating surfaces.
  14. 14. A method of assembling a vacuum pump, the method comprising: assembling a rotor assembly in accordance with the method of claim 13; providing a stator comprising: a pumping chamber; and a plate seat formed from one or more walls of the pumping chamber, the plate seat being formed between a first pumping stage of the vacuum pump and a second pumping stage of the vacuum pump; inserting the rotor assembly into the pumping chamber thereby moving the interstage plate into contact with the plate seat; and fastening the interstage plate to the plate seat.
  15. 15. The method of claim 14, wherein the inserting the rotor assembly into the pumping chamber comprises moving the rotor assembly in a vertical direction.

Description

INTERSTAGE PLATE FOR A VACUUM PUMP FIELD OF THE INVENTION The present invention relates to an interstage plate system for forming an interstage plate for a vacuum pump, a rotor assembly for a vacuum, and a vacuum pump. The present invention relates to methods of assembly for a rotor assembly and a vacuum pump. BACKGROUND Vacuum pumps comprising multiple pumping stages are known. Also, compound vacuum pumps comprising multiple stages with different respective pump types are known. For example, Roots-screw compound vacuum pumps may comprise a first pumping stage housing intermeshed Roots rotors in fluid communication with a second pumping stage housing intermeshed screw rotors. SUMMARY OF THE INVENTION In an aspect, there is provided an interstage plate system comprising a first plate portion comprising a first recess in a first mating surface of the first plate portion, and a second plate portion comprising a second recess in a second mating surface of the second plate portion. The first plate portion and the second plate portion are configured to be coupled together so as to form an interstage plate for a vacuum pump and such that: the first mating surface and the second mating surface abut; and the first recess and the second recess are opposing, contiguous recesses which together form an aperture through the interstage plate. The first plate portion may further comprise a third recess in the first mating surface. The second plate portion may further comprise a fourth recess in the second mating surface. The first plate portion and the second plate portion may be further configured such that, when couped together to form the interstage plate, the third recess and the fourth recess are opposing, contiguous recesses which together form a further aperture through the interstage plate. The second plate portion may comprise a fifth recess, which may be formed in a surface of the second plate portion other than the second mating surface. For example, the fifth recess may be in a surface of the second plate portion that is opposite to the second mating surface. In a further aspect, there is provided a rotor assembly for a vacuum pump. The rotor assembly comprises: an interstage plate formed by the interstage plate system of the preceding aspect, a first rotor, a second rotor, and a first shaft. The first rotor and the second rotor are coaxially aligned and fixed to the first shaft. The first shaft passes through the aperture in the interstage plate formed by the first and second recesses. The interstage plate is disposed between the first rotor and the second rotor. The first rotor may be a Roots rotor. The second rotor may be a screw rotor. The rotor assembly may further comprise a third rotor, a fourth rotor, and a second shaft. The interstage plate comprise a further aperture therethrough, which may be formed by the third recess and the fourth recess. The third rotor and the fourth rotor may be coaxially aligned and fixed to the second shaft. The second shaft may pass through the further aperture in the interstage plate. The interstage plate may be disposed between the third rotor and the fourth rotor. The second shaft may be substantially parallel with the first shaft. The third rotor may be a Roots rotor. The fourth rotor may be a screw rotor. The first rotor and the third rotor may be intermeshed. The second rotor and the fourth rotor may be intermeshed. In a further aspect, there is provided a vacuum pump comprising a stator having a pumping chamber, and the rotor assembly of any preceding aspect. The rotor assembly is at least partially disposed within the pumping chamber. The stator may comprise a plate seat formed from one or more walls of the pumping chamber. The plate seat may be formed between a first pumping stage of the vacuum pump and a second pumping stage of the vacuum pump. The interstage plate may engage the plate seat. The interstage plate may be fixedly attached to the plate seat. The interstage plate may be formed from the same material as the material from which the stator is formed. In a further aspect, there is provided a method of assembling a rotor assembly. The method comprises: providing a first rotor shaft assembly comprising a first rotor, a second rotor, and a first shaft, wherein the first rotor and the second rotor are coaxially aligned and fixed to the first shaft. The method further comprises providing an interstage plate system comprising a first plate portion comprising a first recess, and a second plate portion comprising a second recess. The method further comprises clamping the first plate portion and the second plate portion about the first shaft such that: the first plate portion and the second plate portion together form an interstage plate disposed between the first rotor and the second rotor; the first recess and the second recess are opposing, contiguous recesses which together form a first aperture through the interstage plate; and the first shaft passes throug