Contactless centrifugal pump

Abstract

A centrifugal pump for use with a liquid is disclosed. The pump includes a hollow casing arrangement, a rotor and a magnet arrangement. The casing arrangement defines an interior and an intersecting axis, an intake port for receiving said liquid in use and communicating same to said interior and a discharge port communicating with the interior. The rotor is positioned in said interior and rotatable about said axis in spaced relation to said casing. The rotor includes a drive member, a shaft extending axially from the drive member and an impeller coupled to said drive member by said shaft for rotation therewith and adapted to cause fluid from said interior to be ejected through said discharge port upon rotation. The magnet arrangement is disposed outside said interior and is adapted to drive rotation of said drive member about said axis in use through the creation of a rotating magnetic field.

1 . A centrifugal pump for use with a liquid, said pump comprising: 
 a hollow casing arrangement defining an interior, an axis intersecting the interior, an intake port for receiving said liquid in use and communicating same to said interior and a discharge port communicating with the interior;    a rotor positioned in said interior and rotatable about said axis in spaced relation to said hollow casing arrangement, said rotor including: 
 a drive member;  
 a shaft extending axially from the drive member; and  
 an impeller coupled to said drive member by said shaft for rotation therewith and adapted to cause fluid from said interior to be ejected through said discharge port upon said rotation, and  
   a magnet arrangement disposed outside said interior and adapted to drive rotation of said drive member about said axis in use through the creation of a rotating magnetic field.    
   
   
       2 . A centrifugal pump for use with a liquid and a motor, said pump comprising: 
 a hollow casing arrangement defining an interior, an axis intersecting the interior, an intake port for receiving said liquid in use and communicating same to said interior and a discharge port communicating with the interior;    a rotor positioned in said interior and rotatable about said axis in spaced relation to said hollow casing arrangement, said rotor including an impeller adapted to cause fluid from said interior to be ejected through said discharge port upon said rotation; and    a magnet arrangement disposed outside said interior, coupled to said motor in use and adapted to drive rotation of said rotor about said axis in use through the creation of a rotating magnetic field,    the rotor and casing arrangement being adapted such that, in use, said liquid supports said rotor for rotation substantially about said axis in spaced relation to said hollow casing arrangement.    
   
   
       3 . A centrifugal pump according to  claim 1 , wherein 
 the impeller is a closed impeller;    the hollow casing arrangement includes 
 a central casing defining a hole through which the shaft extends  
 a front casing defining, in combination with the central casing, a portion of the interior in which the impeller is positioned; and  
 a rear casing defining, in combination with the central casing, a portion of the interior in which the drive member is positioned; and  
   in use, the intake port is horizontally disposed relative to said impeller and the discharge port is upwardly disposed relative to said impeller.    
   
   
       4 . A centrifugal pump according to  claim 2 , wherein the rotor and casing arrangement are shaped such that 
 a first portion of the space between the rotor and the casing arrangement, in use, measured radially, undulates in magnitude around the impeller for stabilizing the rotor against radial movement; and    a second portion of the space between the rotor and the casing arrangement, in use, measured axially, undulates in magnitude around the impeller for stabilizing the rotor against axial movement.    
   
   
       5 . A centrifugal pump according to  claim 4 , wherein measured radially, in the direction of rotation of the rotor, in each undulation in the first portion the space between the rotor and the casing arrangement gradually decreases and then quickly increases.  
   
   
       6 . A centrifugal pump according to  claim 5 , wherein measured axially, in the direction of rotation of the rotor, in each undulation in the second portion the space between the rotor and the casing arrangement gradually decreases and then quickly increases.  
   
   
       7 . A centrifugal pump according to  claim 6 , wherein 
 the impeller has projecting from axially opposite sides thereof a pair of circular flanges, arranged coaxial with the axis;    the casing arrangement has defined therein a pair of circular channels in which the flanges rotate in use;    the channels have defined therein a plurality of first wedge-shaped protuberances; and    the spaces between the flanges, channels and first wedge-shaped protuberances define the first portion.    
   
   
       8 . A centrifugal pump according to  claim 7 , wherein the first wedge-shaped protuberances are circumferentially spaced-apart from one another and disposed radially outwardly from the flanges.  
   
   
       9 . A centrifugal pump according to  claim 7 , wherein 
 the casing arrangement has defined thereon, on axially opposite sides of and in spaced relation to the impeller, a plurality of second wedge-shaped protuberances; and    the spaces between the impeller and the second wedge-shaped protuberances define the second portion.    
   
   
       10 . A centrifugal pump according to  claim 9 , wherein the second wedge-shaped protuberances are formed on a pair of annular inserts fitted in hollows formed, respectively, on the front and central casing.  
   
   
       11 . A centrifugal pump according to  claim 2 , wherein the rotor further comprises a drive member and a shaft coupling the rotor to the drive member for rotation therewith, and wherein the magnet arrangement is adapted to drive said rotation of said rotor by causing rotation of said drive member.  
   
   
       12 . A centrifugal pump according to  claim 11 , wherein the rotor and casing arrangement are shaped such that 
 a third portion of the space between the rotor and the casing arrangement, in use, measured radially, undulates in magnitude around the drive member for stabilizing the rotor against radial movement.    
   
   
       13 . A centrifugal pump according to  claim 12 , wherein measured radially, in the direction of rotation of the rotor, in each undulation in the third portion the space between the rotor and the casing arrangement gradually decreases and then quickly increases.  
   
   
       14 . A centrifugal pump according to  claim 13 , wherein the drive member has projecting in an axial direction therefrom a circular flange, arranged coaxial with the axis; the casing arrangement has defined therein a circular channel in which the flange rotates in use; the channel has defined therein a plurality of first wedge-shaped protuberances; and the space between the flange, channel and first wedge-shaped protuberances define the third portion.  
   
   
       15 . A centrifugal pump according to  claim 14 , wherein the first wedge-shaped protuberances are circumferentially spaced-apart from one another and disposed radially outwardly from the flanges.  
   
   
       16 . A centrifugal pump according to  claim 2 , wherein said adaptation of the rotor and casing arrangement, such that said liquid supports said rotor in use for rotation substantially about said axis in spaced relation to said hollow casing arrangement, comprises: 
 a first wedge device which arrests radial translation of the rotor in use; and    a second wedge device which arrests axial translation of the rotor in use.    
   
   
       17 . A centrifugal pump according to  claim 1 , further comprising: 
 a first wedge device which arrests radial translation of the rotor in use; and    a second wedge device which arrests axial translation of the rotor in use.    
   
   
       18 . A centrifugal pump according to  claim 3 , further comprising: 
 a first wedge device which arrests radial translation of the rotor in use; and    a second wedge device which arrests axial translation of the rotor in use.    
   
   
       19 . A centrifugal pump according to  claim 1 , wherein the shaft has positioned thereon at least one wing for arresting liquid flow from the impeller towards the drive member in use.  
   
   
       20 . A centrifugal pump according to  claim 19 , wherein said at least one wing is a spiral wing.  
   
   
       21 . A centrifugal pump according to  claim 19 , further comprising a conduit providing for fluid communication between a portion of the interior in which the drive member is positioned and the intake port.  
   
   
       22 . A centrifugal pump according to  claim 1 , wherein 
 the drive member comprises: a rotor plate having a rim; and a non-magnetic electrical conductor secured to said rim, the conductor having a surface coated in an insulator,    the casing arrangement includes a non-magnetic electrical insulating barrier between the conductor and the magnet arrangement, and    the magnet arrangement comprises two sets of permanent magnets surrounding said conductor and rotatable in use such that, upon said rotation, said rotating magnetic field is generated between the two sets of magnets to intersect the conductor.    
   
   
       23 . A centrifugal pump according to  claim 22 , wherein 
 the conductor is an annular disc; and    each of the two sets of permanent magnets includes an even number of permanent magnets arranged in an arc and attached to a yoke,    the yokes of the two sets being connected together and the two sets of permanent magnets being axially spaced from one another.    
   
   
       24 . A centrifugal pump according to  claim 22 , wherein 
 the conductor is a hollow cylinder; and    each of the two sets of permanent magnets includes an even number of permanent magnets arranged in an arc and attached to a cylindrical yoke,    the yokes of the two sets being connected together and the two sets of permanent magnets being radially spaced from one another.    
   
   
       25 . In combination, 
 a centrifugal pump according to  claim 2;  and    a motor, said motor being coupled to said magnet arrangement and, in use, driving said magnet arrangement to create said rotating magnetic field.