Scroll pump with axial load control system

Abstract

A scroll pump includes a first scroll member and a second scroll member. An electromagnet is fixedly connected to one of the first scroll member and a second scroll member, and a magnetic target is fixedly connected to the other of the first scroll member and the second scroll member. The electromagnet is operable to generate a magnetic field between the electromagnet and the magnetic target, thereby establishing an axially-directed magnetic biasing force between the first scroll member and the second scroll member.

1 . A scroll pump comprising:
 a first scroll member, the first scroll member comprising:
 a first end plate; and 
 a first scroll extending in an axial direction from the first end plate to a first scroll tip; 
   a second scroll member, the second scroll member comprising:
 a second end plate; and 
 a second scroll extending in the axial direction from the second end plate to a second scroll tip, wherein the second scroll is intermeshed with the first scroll, wherein the first scroll member and the second scroll member define a working volume therebetween, and wherein the second scroll is movable in the axial direction with the respect to the first scroll; and 
   an electromagnet fixedly connected to the fixed scroll member, wherein the electromagnet is operable to selectively bias the second scroll member axially with respect to the first scroll member.   
     
     
         2 . The scroll pump of  claim 1  wherein the electromagnet comprises a coil. 
     
     
         3 . The scroll pump of  claim 2  wherein the electromagnet further comprises a ferromagnetic core. 
     
     
         4 . The scroll pump of any preceding claim further comprising a magnetic target fixed to the other of the first scroll member and the second scroll member. 
     
     
         5 . The scroll pump of  claim 4  wherein the magnetic target comprises a ferrous target made of ferromagnetic material. 
     
     
         6 . The scroll pump of  claim 4  wherein the magnetic target comprises a permanent magnet. 
     
     
         7 . The scroll pump of any preceding claim further comprising a spring associated with the first scroll member and the second scroll member and operable to bias the second scroll member toward the first scroll member. 
     
     
         8 . The scroll pump of any of any preceding claim further comprising a controller operable to selectively energize and de-energize the coil and thereby selectively cause the electromagnet to bias the second scroll member axially with respect to the first scroll member. 
     
     
         9 . The scroll pump of  claim 8  wherein the controller is operable to selectively cause the electromagnet to bias the second scroll member away from the first scroll member. 
     
     
         10 . The scroll pump of  claim 8  wherein the controller is operable to selectively cause the electromagnet to bias the second scroll member toward the first scroll member. 
     
     
         11 . The scroll pump of  claim 8  wherein the controller is operable to selectively cause the electromagnet to bias the second scroll member toward the first scroll member to mitigate leakage of a working fluid between the first scroll and the second scroll. 
     
     
         12 . The scroll pump of  claim 8  wherein the controller is operable to selectively cause the electromagnet to bias the second scroll member away from the first scroll member to induce leakage of a working fluid between the first scroll and the second scroll.