Dry vacuum scroll pump

Abstract

A dry scroll vacuum pump includes a fixed scroll, a drive shaft having an axis and an eccentric shaft portion, an orbiting scroll connected to the eccentric shaft portion so that during use rotation of the shaft imparts an orbiting motion to the orbiting scroll relative to the fixed scroll for pumping gas between a mechanism inlet and a mechanism outlet of a scroll mechanism comprising the scrolls; an inlet vacuum region for conveying gas from the pump inlet to the mechanism inlet; a cooling flow path formed inside the orbiting scroll for guiding a cooling fluid for cooling the orbiting scroll, the cooling flow path having a fluid inlet; and a sealing arrangement for sealing the fluid inlet from the inlet vacuum region so a cooling fluid can be conveyed across the inlet vacuum region through the sealing arrangement to the fluid inlet.

1 . A dry scroll vacuum pump comprising:
 a pump housing having a housing inlet and a housing outlet;   a fixed scroll fixed relative to the pump housing;   a drive shaft having an axis and an eccentric shaft portion;   an orbiting scroll connected to the eccentric shaft portion so that during use rotation of the shaft imparts an orbiting motion to the orbiting scroll relative to the fixed scroll for pumping gas between a mechanism inlet and a mechanism outlet of a scroll mechanism comprising the scrolls;   an inlet vacuum region at inlet pressure within the pump housing for conveying gas from the pump inlet to the mechanism inlet during said orbiting motion;   a cooling flow path formed inside the orbiting scroll for guiding flow of a cooling fluid for cooling the orbiting scroll, the cooling flow path having a fluid inlet located in the inlet vacuum region; and   a sealing arrangement for sealing the fluid inlet from the inlet vacuum region so a cooling fluid can be conveyed across the inlet vacuum region through the sealing arrangement to the fluid inlet.   
     
     
         2 . The dry vacuum scroll pump as claimed in  claim 1 , wherein the cooling flow path has a fluid outlet located in the inlet vacuum region and the sealing arrangement seals the fluid outlet from the inlet vacuum region so that low vacuum cooling fluid can be conveyed across the inlet vacuum region through the sealing arrangement to the fluid outlet. 
     
     
         3 . The dry vacuum scroll pump as claimed in  claim 1 , having a reverse scroll arrangement wherein the fixed scroll has an opening through which the shaft extends and is connected to the orbiting scroll with the orbiting scroll on an opposing side of the fixed scroll to a drive motor, and the inlet vacuum region is located adjacent the orbiting scroll. 
     
     
         4 . The dry vacuum scroll pump as claimed in  claim 1 , wherein the sealing arrangement has an inlet seal having a first inlet portion fixed at the fluid inlet of the orbiting scroll, a second inlet portion fixed relative to a pump housing fluid inlet through which cooling fluid is conveyed, and a connecting inlet portion which is flexible to allow relative orbiting motion between the first inlet portion and the second inlet portion during movement of the orbiting scroll in two orthogonal dimensions with respect to the axis. 
     
     
         5 . The dry vacuum scroll pump as claimed in  claim 1 , wherein the sealing arrangement has an outlet seal having a first outlet portion fixed at the fluid outlet of the orbiting scroll, a second outlet portion fixed relative to a pump housing fluid outlet through which cooling fluid is conveyed, and a connecting outlet portion which is flexible to allow relative orbiting motion between the first outlet portion and the second outlet portion during movement of the orbiting scroll in two orthogonal dimensions with respect to the axis. 
     
     
         6 . The dry vacuum scroll pump as claimed in  claim 4 , wherein the inlet and/or outlet seal comprises a gaiter seal. 
     
     
         7 . The dry vacuum scroll pump as claimed in  claim 1 , comprising a source of cooling fluid configured for conveying cooling fluid through the cooling flow path of the orbiting scroll. 
     
     
         8 . The dry vacuum scroll pump as claimed in  claim 7 , wherein the flow source comprises a mechanical fan rotated by the drive shaft. 
     
     
         9 . The dry vacuum scroll pump as claimed in  claim 1 , wherein the source of cooling fluid comprises a pump external to the pump housing for conveying cooling fluid through the cooling flow path. 
     
     
         10 . The dry vacuum scroll pump as claimed in  claim 1 , wherein the source of cooling fluid is caused by motion of the fluid inlet to convey cooling fluid through the cooling path. 
     
     
         11 . The dry vacuum scroll pump as claimed in  claim 1 , wherein the cooling flow path is formed by casting within the orbiting scroll during manufacture. 
     
     
         12 . The dry vacuum scroll pump as claimed in  claim 1 , wherein the cooling flow path has a tortuous configuration within the orbiting scroll. 
     
     
         13 . The dry vacuum scroll pump as claimed in  claim 1 , wherein the cooling fluid is air or water. 
     
     
         14 . The dry vacuum scroll pump as claimed in  claim 1 , wherein the cooling fluid is at or in the region of atmospheric pressure 1 bar to 0.5 bar and preferably 1.0 to 1.2 bar. 
     
     
         15 . (canceled)