Fluid pump

Abstract

A fluid pump includes an inlet; an outlet; a motor; and an impeller rotated by the motor about an axis, the impeller being positioned axially between an inlet plate and an outlet plate. The inlet plate includes a channel that receives fluid from the inlet, the channel being defined by an inner wall and an outer wall. The channel has a first region extending over an angle of at least 150° and a second region extending from the first region over an angle of 61.8° to 71.8°. The inner wall has a first radius centered about the axis which is constant over the first region and the second region. The outer wall has a second radius centered about the axis which is constant over the first region and also has a third radius not centered about the axis which is constant over the second region.

We claim: 
     
         1 . A fluid pump comprising:
 an inlet which introduces fluid into said fluid pump;   an outlet which discharges fluid from said fluid pump;   a motor within said fluid pump; and   a pumping member rotated by said motor about an axis such that rotation of said pumping member by said motor pumps fluid from said inlet to said outlet, said pumping member being positioned axially between an inlet plate which is stationary and an outlet plate which is stationary;   said inlet plate includes an inlet plate flow channel in an inlet plate face of said inlet plate that faces toward said pumping member such that said inlet plate flow channel receives fluid from said inlet, said inlet plate flow channel being defined by an inner wall and an outer wall wherein:   said inlet plate flow channel has a first region and a second region, said first region extending over an angle of at least 150° and said second region extending from said first region over an angle of 61.8° to 71.8°;   said inner wall has a first radius which is constant over said first region and said second region, said first radius being centered about said axis; and   said outer wall has a second radius which is constant over said first region and which is centered about said axis, said outer wall also has a third radius which is constant over said second region and which is not centered about said axis.   
     
     
         2 . A fluid pump as in  claim 1  wherein said second region of said inlet plate flow channel has a first end that is proximal to said first region and a second end which is distal from said first region and terminates said inlet plate flow channel. 
     
     
         3 . A fluid pump as in  claim 2  wherein said outer wall converges to said inner wall at said second end. 
     
     
         4 . A fluid pump as in  claim 1  wherein said third radius is less than said second radius. 
     
     
         5 . A fluid pump as in  claim 1  wherein:
 said inlet plate flow channel is further defined by a bottom wall which connects said inner wall to said outer wall; and 
 said bottom wall tapers over the entirety of said second region, thereby varying the depth of said inlet plate flow channel within said second region. 
 
     
     
         6 . A fluid pump as in  claim 5  wherein said bottom wall tapers at a constant rate over the entirety of said second region. 
     
     
         7 . A fluid pump as in  claim 6  wherein said bottom wall tapers at said constant rate over the entirety of said second region to said inlet plate face. 
     
     
         8 . A fluid pump as in  claim 5  wherein:
 said bottom wall has an initial tapered section within said second region such that said initial tapered section is proximal to said first region; 
 said bottom wall has a final tapered section within said second region such that said initial tapered section is between said final tapered section and said first region; 
 said initial tapered section tapers at a first constant rate from said first region to said final tapered section; and 
 said final tapered section tapers at a second constant rate from said initial tapered section. 
 
     
     
         9 . A fluid pump as in  claim 8  wherein: said first constant rate is greater than said second constant rate. 
     
     
         10 . A fluid pump as in  claim 9  wherein said final tapered section tapers from said initial tapered section to said inlet plate face. 
     
     
         11 . A fluid pump as in  claim 1  wherein said third radius is centered about a center point which is laterally offset from said axis toward said first region. 
     
     
         12 . A fluid pump as in  claim 11  wherein said center point is offset from said axis toward said second region in addition to toward said first region. 
     
     
         13 . A fluid pump as in  claim 1  wherein:
 said inlet plate flow channel has an inlet region at one end of said inlet plate flow channel such that said first region is between said inlet region and said second region and such that said inlet opens into said inlet region; and 
 said second region terminates said inlet plate flow channel.