Wobble piston pump with carbon graphite cylinder

Abstract

A two-cylinder axial displacement wobble piston air compressor/vacuum pump ( 10 ) has a pair of open-ended cylinder sleeves ( 36 ) lining the pump chambers ( 34 ) of the housing ( 16 ).The cylinder sleeves are made of a pressed powder carbon graphite material that is impregnated with a phenolic resin. The wobble pistons ( 18 ) include a piston cup ( 48 ) made of a PTFE material and having a diameter sized to abut the bore of the cylinder throughout the compression and suction strokes of the piston.

1 . In a pump having a housing containing a rotatable shaft extending into a pump chamber having a cylinder through which travels a wobble piston eccentrically mounted at one end to the shaft and having a head at an opposite end that is pivotal with respect to a cylinder axis, the improvement wherein the cylinder is a carbon graphite composition.  
   
   
       2 . The improvement of  claim 1 , wherein the cylinder is an open-ended cylindrical sleeve separate from the housing lining the inside of the pump chamber.  
   
   
       3 . The improvement of  claim 2 , wherein the cylinder is a pressed carbon graphite powder.  
   
   
       4 . The improvement of  claim 3 , wherein the carbon graphite powder is impregnated with a thermoset resin.  
   
   
       5 . The improvement of  claim 4 , wherein the thermoset resin is a phenolic.  
   
   
       6 . The improvement of  claim 1 , wherein the piston head includes a piston cup having a periphery with a diameter larger than the piston head sized to abut an inner diameter of the cylinder throughout compression and suction strokes.  
   
   
       7 . The improvement of  claim 1 , wherein the housing includes multiple pump chambers, each having an associated wobble piston and graphite cylinder.  
   
   
       8 . A pump, comprising: 
 a housing defining a pump chamber and housing a rotatable shaft extending into the pump chamber;    a carbon graphite cylinder lining the inside of the pump chamber; and    a wobble piston mounted to the shaft so as to reciprocate within the cylinder and pivot, with respect to a cylinder axis, wherein the piston includes a piston cup fixedly mounted to a head of the piston opposite its connection to the shaft and having a periphery with a diameter sized to abut an inner diameter of the cylinder throughout compression and suction strokes of the piston.    
   
   
       9 . The pump of  claim 8 , wherein the piston cup is a PTFE composition.  
   
   
       10 . The pump of  claim 9 , wherein the cylinder is a pressed carbon graphite powder.  
   
   
       11 . The pump of  claim 10 , wherein the carbon graphite powder is impregnated with a phenolic resin.  
   
   
       12 . The pump of  claim 8 , wherein the housing includes multiple pump chambers, each having an associated wobble piston and carbon graphite cylinder.