Pump device

Abstract

A centrifugal pump for use with a liquid forms one aspect of the invention. This pump comprises a housing and a rotor. The housing has an interior surface defining an interior cavity, an axis intersecting the cavity, an intake port for receiving liquid and communicating same to said cavity, and a discharge port in communication with said cavity. The rotor has an impeller, is positioned in said cavity and is rotatable in said cavity about said axis in spaced relation to the interior surface. The impeller is adapted to force said liquid to flow through said discharge port upon said rotation in use. The pump further comprises means for balancing the pressure in said cavity, adapted so as to avoid the creation of pressure differentials in said cavity that would otherwise in use tend to cause translation of said rotor in said cavity. The pump further comprises a rotating magnetic field generation device adapted to drive rotation of said rotor about said axis in use.

1 . A centrifugal pump for use with a liquid, said pump comprising: 
 a housing having an interior surface defining an interior cavity, an axis intersecting the cavity, an intake port for receiving liquid and communicating same to said cavity, and a discharge port in communication with said cavity;    a rotor having an impeller, said rotor being positioned in said cavity and rotatable in said cavity about said axis in spaced relation to the interior surface, the impeller being adapted to force said liquid to flow through said discharge port upon said rotation in use;    means for balancing the pressure in said cavity, adapted so as to avoid the creation of pressure differentials in said cavity that would otherwise in use tend to cause translation of said rotor in said cavity; and    a rotating magnetic field generation device adapted to drive rotation of said rotor about said axis in use.    
   
   
       2 . A pump according to  claim 1 , wherein the means for balancing the pressure in said cavity is a liquid conduit.  
   
   
       3 . A pump according to  claim 2 , wherein, in use, the discharge port is disposed above the impeller and the liquid conduit extends between a first terminus in the cavity above the impeller and a second terminus in the cavity below the impeller.  
   
   
       4 . A pump according to  claim 3 , wherein the liquid conduit is defined at least in part by an arc-shaped barrier.  
   
   
       5 . A pump according to  claim 1 , wherein the rotor includes a drive member to which is coupled the impeller, for rotation therewith, and wherein the rotating magnetic field generation device is adapted to drive rotation of said rotor about said axis in use by driving rotation of said drive member.  
   
   
       6 . A pump according to  claim 5 , wherein the impeller is a closed impeller having axially-spaced sides and wherein the drive member comprises a metal tube extending axially from one of the sides of the impeller and arranged coaxial with the axis.  
   
   
       7 . A pump according to  claim 1 , wherein the rotor and housing are adapted such that, in use, said liquid supports said rotor for rotation substantially about said axis in spaced relation to said interior surface.  
   
   
       8 . A pump according to  claim 6 , wherein the rotor and housing are adapted such that, in use, said liquid supports said rotor for rotation substantially about said axis in spaced relation to said interior surface.  
   
   
       9 . A pump according to  claim 8 , wherein said adaptation of the rotor and housing, such that, in use, said liquid supports said rotor for rotation substantially about said axis in spaced relation to said interior surface, comprises: 
 a balance tube extending from the other of the sides of the impeller in a direction coaxial with and opposite to the drive member, and    a circular groove forming part of said cavity in which a rim of the balance tube revolves in use.    
   
   
       10 . A pump according to  claim 8 , wherein said adaptation of the rotor and housing, such that, in use, said liquid supports said rotor for rotation substantially about said axis in spaced relation to said interior surface, comprises: 
 for each side of the impeller, a plurality of protrusions defined by the interior surface such that the space between the rotor and the housing, in use, measured axially, undulates in magnitude around the impeller for stabilizing the rotor against axial movement.    
   
   
       11 . A pump according to  claim 10 , wherein, measured axially, in the direction of rotation of the rotor, in each protrusion the space between the rotor and the housing gradually decreases and then quickly increases.  
   
   
       12 . A pump according to  claim 10 , wherein each plurality of protrusions has associated therewith a series of radial grooves forming part of the cavity, the grooves separating the protrusions from one another.  
   
   
       13 . A pump according to  claim 10 , wherein each protrusion comprises a wedge-shaped slope inclined in the direction of rotation of the rotor.  
   
   
       14 . A pump according to  claim 1 , wherein the impeller has defined therethrough, coaxial with the axis, an intake hole, and wherein the housing comprises an inflow regulation boss projecting into the cavity that extends, coaxially with the axis, into the intake hole.  
   
   
       15 . A pump according to  claim 14 , wherein the inflow regulation boss is shaped to direct flow impinging thereupon into the impeller.  
   
   
       16 . A pump according to  claim 14 , wherein the inflow regulation boss has a conical tip to direct flow impinging thereupon into the impeller.  
   
   
       17 . A pump according to  claim 15 , further comprising a tubular intake portion attached to the rim of the intake port and that extends, coaxially with the axis, into the intake hole and towards the inflow regulation boss, to direct flow thereupon.  
   
   
       18 . A pump according to  claim 1 , wherein the impeller has defined therethrough, coaxial with the axis, an intake hole, and further comprising a tubular intake portion attached to the rim of the intake port and that extends, coaxially with the axis, into the intake hole.  
   
   
       19 . A pump according to  claim 1 , wherein the impeller has axially-spaced sides and further comprising extension plates attached around the perimeter of the impeller to increase the area of the impeller sides.  
   
   
       20 . A pump according to  claim 1 , further comprising a liquid detection sensor, capable of detecting the existence of liquid within the cavity and producing a liquid detection signal, and a controller that uses the liquid detection signal from said liquid detection sensor to control the pump during startup.  
   
   
       21 . A centrifugal pump for use with a liquid, said pump comprising: 
 a housing having an interior surface defining an interior cavity, an axis intersecting the cavity, an intake port for receiving liquid and communicating same to said cavity, and a discharge port in communication with said cavity;    a rotor having an impeller, said rotor being positioned in said cavity and rotatable in said cavity about said axis in spaced relation to the interior surface, the impeller being adapted to force said liquid to flow through said discharge port upon said rotation in use;    a liquid conduit for balancing the pressure in said cavity so as to avoid the creation of pressure differentials in said cavity that would otherwise in use tend to cause translation of said rotor in said cavity towards said discharge port; and    a rotating magnetic field generation device adapted to drive rotation of said rotor about said axis in use.