Fluid pump

Abstract

A fluid pump includes a chamber and a plunger extending into the chamber and supported for sliding movement on a suction stroke to introduce fluid into the chamber and on a discharge stroke to force fluid out of the chamber. A driver slides the pumping member in opposite directions. A seal ring is located between the chamber and the pumping member and permits the sliding movement of the pumping member. The seal ring has an outer annular portion having a generally flat cross-section, clamped in a wall of the chamber and an inner annular portion having a bulbous cross-section and in sliding sealing engagement with the pumping member.

1 . A fluid pump comprising: 
 a chamber having an inlet and an outlet;    a pumping member extending into the chamber and supported for sliding movement on a suction stroke in first directions outwardly of the chamber, to introduce fluid into the chamber via the inlet and, on a discharge stroke in a second direction, opposite the first direction, inwardly of the chamber, to force fluid out of the chamber via the outlet;    a driver for sliding the pumping member in first and second directions; and    a seal ring located between the chamber and the pumping member and permitting the sliding movement of the pumping member relative to the chamber, wherein the seal ring has a first annular portion clamped in a wall of one of the chamber and the pumping member, and a second annular portion, having a bulbous cross-section, in sliding sealing engagement with a wall of the other of the chamber and the pumping member.    
   
   
       2 . The fluid pump as claimed in  claim 1 , wherein the bulbous cross-section is thicker than the first annular portion.  
   
   
       3 . The fluid pump as claimed in  claim 1 , wherein the bulbous cross-section is at least partially circular.  
   
   
       4 . The fluid pump as claimed in  claim 1 , wherein the first and second annular portions have cross-sections that are symmetrical about a common central axis.  
   
   
       5 . The fluid pump as claimed in  claim 1 , wherein the first annular portion has a cross-section that is generally flat.  
   
   
       6 . The fluid pump as claimed in  claim 1 , wherein the first annular portion has a cross-section that is generally T-shaped.  
   
   
       7 . The fluid pump as claimed in  claim 1 , wherein the first and second annular portions have a combined cross-section that is generally dumbbell-shaped.  
   
   
       8 . The fluid pump as claimed in  claim 1 , wherein the seal ring has an outer annular portion as the first annular portion, clamped in the wall of the chamber, and an inner annular portion as the second annular portion, in sliding sealing engagement with the wall of the pumping member.  
   
   
       9 . The fluid pump as claimed in  claim 8 , wherein the seal ring is located at an opening of the chamber, through which the pumping member extends into the chamber.  
   
   
       10 . The fluid pump as claimed in  claim 9 , wherein the opening coincides with the inlet of the chamber.  
   
   
       11 . The fluid pump as claimed in  claim 1 , wherein a part of the second annular portion of the seal ring is also clamped in the wall of the one of the chamber and the pumping member.  
   
   
       12 . The fluid pump as claimed in  claim 1 , wherein the pumping member has a bore that is the inlet of the chamber.  
   
   
       13 . The fluid pump as claimed in  claim 1 , wherein the pumping member comprises a plunger.  
   
   
       14 . The fluid pump as claimed in  claim 1 , including one-way valves located at the inlet and the outlet respectively.  
   
   
       15 . The fluid pump as claimed in  claim 1 , wherein the driver is an electro-mechanical driver.  
   
   
       16 . The fluid pump as claimed in  claim 15 , wherein the driver includes a solenoid comprising an electromagnetic coil surrounding a ferro-magnetic plunger and the pumping member comprises a front end of the plunger.