Multi-stage vacuum booster pump coupling

Abstract

A multi-stage vacuum pump having an interstage coupling unit vacuum pump may include a first inter-stage coupling part defining a first portion of a void for receiving a common rotor shared by adjacent stages of the multi-stage vacuum pump; and a second inter-stage coupling part separable from the first inter-stage coupling part, the second inter-stage coupling part defining a second portion of the void for receiving the common rotor shared by adjacent stages of the multi-stage vacuum pump. In this way, a coupling is provided which enables an assembled rotor and assembled stages of the vacuum pump to be fixed together, since the assembled rotor can be received within the separable parts of the coupling which, in turn, can be fitted to the assembled adjacent stages. This enables the mechanical integrity of the rotor and adjacent stages to be preserved while still facilitating assembly of the multi-stage vacuum pump.

1 : A multi-stage vacuum pump comprising:
 a first pumping stage comprising a first unitary stator;   a second pumping stage comprising a second unitary stator; and   an inter-stage coupling unit configured to couple the first pumping stage with the second pumping stage, the inter-stage coupling unit comprising:
 a first inter-stage coupling part defining a first portion of a void for receiving a common rotor shared by adjacent stages of the multi-stage vacuum pump; and 
 a second inter-stage coupling part separable from the first inter-stage coupling part, the second inter-stage coupling part defining a second portion of the void for receiving the common rotor shared by adjacent stages of the multi-stage vacuum pump. 
   
     
     
         2 : The vacuum pump according to  claim 1 , wherein the second unitary stator is configured to receive the inter-stage coupling unit therewithin. 
     
     
         3 : The vacuum pump according to  claim 1 , wherein the first inter-stage coupling part defines a first portion of first and second coupling faces and the second inter-stage coupling part defines a second portion of first and second coupling faces and the void extends between the first and second coupling faces. 
     
     
         4 : The vacuum pump according to  claim 3 , wherein each of the first and second coupling faces is configured to be received by a respective adjacent stage of the multi-stage vacuum pump. 
     
     
         5 : The vacuum pump according to  claim 3 , wherein each of the first and second coupling faces is configured as a head plate to seal an end of the respective adjacent stage of the multi-stage vacuum pump. 
     
     
         6 : The vacuum pump according to  claim 3 , wherein the first coupling face defines an inlet aperture to receive an exhaust from a first adjacent stage of the said multi-stage vacuum pump and the second coupling face defines an outlet aperture to deliver said exhaust to a second adjacent stage of the multi-stage vacuum pump and the first and second inter-stage coupling parts define a transfer conduit configured to fluidly couple the inlet aperture with the outlet aperture. 
     
     
         7 : The vacuum pump according to  claim 6 , wherein the inlet aperture is located fluidly downstream of the first adjacent stage of the multi-stage vacuum pump and the outlet aperture is located fluidly upstream of the second adjacent stage of the multi-stage vacuum pump. 
     
     
         8 : The vacuum pump according to  claim 3 , wherein one of the first and second portions of the first coupling face defines the inlet aperture and another of the first and second portions of the second coupling face defines the outlet aperture. 
     
     
         9 : The vacuum pump according to  claim 3 , wherein one of the first and second portions of the first coupling face defines the inlet aperture, another of the first and second portions of the first coupling face defines a recirculation outlet aperture, and the first and second inter-stage coupling parts define a recirculation conduit configured to selectively fluidly couple the inlet aperture with the recirculation outlet aperture. 
     
     
         10 : The vacuum pump according to  claim 3 , wherein one of the first and second portions of the second coupling face define the outlet aperture, another of the first and second portions of the second coupling face defines a second recirculation outlet aperture, and the first and second inter-stage coupling parts define a second recirculation conduit configured to selectively fluidly couple the outlet aperture with the second recirculation outlet aperture. 
     
     
         11 : The vacuum pump according to  claim 9 , wherein the recirculation conduit comprises a pressure-actuated valve actuatable to couple the inlet aperture with the recirculation outlet aperture in response to a selected pressure differential between the inlet aperture and the recirculation outlet aperture. 
     
     
         12 : The vacuum pump according to  claim 11 , wherein the second recirculation conduit comprises a second pressure actuated valve actuatable to couple said outlet aperture with the second recirculation outlet aperture in response to a selected pressure differential between the outlet aperture and the second recirculation outlet.