Vacuum pump

Abstract

A dry vacuum pump comprises a stator component and at least one rotor component. To improve the tolerance of the pump to corrosive gases passing through the pump, the stator component and/or said at least one rotor component are formed from silicon-molybdenum (SiMo) ductile iron.

1 . A dry vacuum pump stator component, wherein the stator component is formed from silicon-molybdenum (SiMo) ductile iron alloy. 
   
   
       2 . A dry vacuum pump rotor component, wherein the rotor component is formed from silicon-molybdenum (SiMo) ductile iron alloy. 
   
   
       3 . A dry vacuum pump comprising a stator component and at least one rotor component, wherein the stator component and/or said at least one rotor component are formed from silicon-molybdenum (SiMo) ductile iron alloy. 
   
   
       4 . The pump according to  claim 3 , wherein the alloy contains silicon in an amount from about 3.5 to about 5 wt %. 
   
   
       5 . The pump according to  claim 3 , wherein the alloy contains molybdenum in an amount from about 0.4 to about 1 wt %. 
   
   
       6 . The pump according to  claim 3 , wherein said at least one rotor component has one of a screw, Roots or Northey profile. 
   
   
       7 . The pump according to  claim 6 , comprising first and second intermeshing rotor components adapted for counter-rotation within the stator component. 
   
   
       8 . The pump according to  claim 7 , wherein intermeshing rotor components are located on respective shafts, the pump comprising a gear assembly for transmitting torque from one shaft to another, at least one gear of the gear assembly being formed from SiMo ductile iron alloy. 
   
   
       9 . The pump according to  claim 3 , in the form of a multi-stage dry vacuum pump in which the stator component defines a plurality of interconnected pumping chambers each housing a respective pair of rotor components each formed from SiMo ductile iron alloy. 
   
   
       10 . The pump according to  claim 3 , in the form of a scroll pump in which the stator component comprises a fixed scroll member having an end plate with a first spiral wrap extending therefrom, and said at least one rotor component comprises an orbital scroll member having an end plate with a second spiral wrap extending therefrom to intermesh with the first spiral wrap.