Gear Pump

Abstract

A gear pump has a face plate 2 cooperating with central plate 24 defining a pump chamber 21 holding gears 16. The pump chamber 21 is in fluid communication with drive chamber 32 holding the rotor 40 of an electric motor. An O-ring 18 may be used to seal the face plate 2 . Other elements may be sealed using a permanent seal such as glue.

1 . A gear pump for pumping a pump fluid, comprising
 a pump chamber ( 21 ) having a first port ( 6 ) and a second port ( 8 ), and a pair of gears ( 16 ) mounted for rotation in the pump chamber for driving pump fluid between the first port ( 6 ) and second port ( 8 );   a motor comprising a rotor ( 40 ) and a drive shaft ( 48 ) connected to the rotor to drive the pair of gears, the drive shaft and rotor being arranged in a drive chamber ( 32 ), the motor further comprising a stator arranged around the drive chamber ( 30 );   wherein the pump chamber ( 21 ) and the drive chamber ( 32 ) are connected to allow pump fluid to pass between them.   
     
     
         2 . A gear pump according to  claim 1 , comprising:
 a face plate ( 2 ) having the first port ( 6 ) and the second port ( 8 );   an central plate ( 24 ), the central plate ( 24 ) and the face plate ( 2 ) defining the pump chamber ( 21 ) between them;   wherein the central plate ( 24 ) has a central opening to provide a fluid path between the pump chamber and the drive chamber and wherein the drive shaft passes through the central opening to drive the gears.   
     
     
         3 . A gear pump according to  claim 2  further comprising an inner plate ( 22 ) sealed to the face plate with an O-ring ( 18 ). 
     
     
         4 . A gear pump according to  claim 2 , further comprising a motor plate ( 34 ) on the opposite end of the gear pump to the face plate, the stator ( 30 ) being provided between the motor plate ( 34 ) and the central plate ( 24 ). 
     
     
         5 . A gear pump according to  claim 4 , wherein the stator ( 30 ) is a sealed unit extending around the drive chamber ( 32 ), one end of the drive chamber being sealed by the motor plate ( 34 ) and the other end of the drive chamber being externally sealed against the central plate ( 24 ). 
     
     
         6 . A gear pump according to  claim 4  wherein the central plate ( 24 ) and motor plate ( 34 ) are sealed to the stator ( 30 ) with a permanent seal. 
     
     
         7 . A gear pump according to  claim 6  wherein the permanent seal is glue. 
     
     
         8 . A gear pump according to  claim 4 , further comprising a plurality of screws ( 44 ) passing through the motor plate ( 34 ) and face plate ( 2 ) arranged in tension to hold urge the face plate ( 2 ) towards the motor plate ( 34 ). 
     
     
         9 . A gear pump according to  claim 8  wherein the face plate ( 2 ) and the motor plate ( 34 ) have flanges ( 4 , 36 ) extending radially outwards from the plate, the screws ( 44 ) passing through the flanges.