Removal of magnetic particles from a fluid

Abstract

An apparatus ( 10 ) for removing magnetic particles from a mud slurry is disclosed. The apparatus ( 10 ) includes one or more endless belts or chains ( 12 ) enclosed almost wholly within a pipe ( 22 a ). A motor ( 28 ) drives the chain ( 22 ) around the pipe ( 22 a ). When the pipe ( 22 a ) is located within a mud slurry, magnetic particles in the mud slurry are drawn to the pipe ( 22 a ) and carried along the outside and away from the slurry until a collar ( 29 ) is reached. Once so separated the particles can be collected for disposal. The chain ( 12 ) comprises a series of units linked together. Each unit includes a magnet ( 50 ) with pole pieces ( 51 a, 51 b ) at either pole to direct magnetic flux. Wear discs ( 52 a, 52 b ) prevent the magnets ( 50 ) and pole pieces ( 51 a, 51 b ) from abrasion as they are drawn through the pipe ( 22 a ). Units can be included in the chain ( 12 ) which units do not include a magnet, thereby providing a break in the field, allowing particles to fall away from the collar region.

1 . An apparatus for removing magnetic particles from a liquid or slurry; said apparatus comprising;
 an endless belt of chain, including along its length, a plurality of magnetic field generation units to attract magnetic particles;   an enclosing means preventing contact of magnetic particles with said magnetic field generation units;   drive means to circulate said endless belt within the said enclosing means; and   collection means to collect the particles.   
   
   
       2 . An apparatus according to  claim 1 , wherein said magnetic field generation unit comprises at least one permanent magnet. 
   
   
       3 . An apparatus according to  claim 2 , wherein said magnetic field generation unit comprises at least one pole piece to direct the magnetic field of said magnets. 
   
   
       4 . An apparatus according to  claim 1 , wherein said magnetic field generation unit includes at least one wear disc ( 52   a ) to reduce wear on a magnet or a pole piece. 
   
   
       5 . An apparatus according to  claim 2 , wherein said magnet includes a hole along its axis. 
   
   
       6 . An apparatus according to  claim 1 , wherein said endless belt or chain comprises a plurality of units linked together. 
   
   
       7 . An apparatus according to  claim 6 , wherein said endless belt or chain includes at least one unit not including a magnet. 
   
   
       8 . An apparatus according to  claim 1 , wherein said apparatus includes a plurality of enclosing means, arranged in an array each enclosing means enclosing said endless belt. 
   
   
       9 . An apparatus according to  claim 8 , wherein the relative positions of said enclosing means can be adjusted. 
   
   
       10 . An apparatus according to  claim 1 , wherein said enclosing means is mounted to mounting means. 
   
   
       11 . An apparatus according to  claim 1 , wherein said enclosing means is formed of steel. 
   
   
       12 . A device for removing magnetic particles from a liquid or slurry, the device comprising;
 an elongate magnetic field generator;   a casing separating said generator from a liquid or slurry;   the magnetic field passing through said casing causing magnetic particles in a slurry to be attracted to said device and be retained on said casing; and   means for removing the attracted particles from the field generated by said generator, enabling the particles to be removed from said device ( 70 ).   
   
   
       13 . A device according to  claim 12 , wherein said device comprises a helical cleaning means, rotatable about the axis of said magnetic field generator, the inner surface of said cleaning means engaging said casing and rotation of said cleaning means moving the attracted particles from the field generated by said generator. 
   
   
       14 . A device according to  claim 12 , wherein said device includes a cleaning barrier, engaging said casing said barrier being movable between a first and second position, the motion causing particles to move out of the field generated by said generator. 
   
   
       15 . A device according to  claim 12 , wherein said magnetic field generator comprises a stack of magnets alternating polarity along the length of the generator. 
   
   
       16 . A device according to  claim 12 , wherein the magnetic poles are orientated along the length of the axis of said magnetic field generator. 
   
   
       17 . A device according to  claim 12 , wherein the poles are orientated perpendicularly to the axis of said magnetic field generator. 
   
   
       18 . An array for removing magnetic particles from a liquid or slurry, the device comprising;
 at least one magnet, said magnet being housed within a casing;   said housing being attached to a framework, which framework being locatable on a fluid-carrying channel, and such that said casing is at least partially immersed in the fluid.   
   
   
       19 . (canceled) 
   
   
       20 . (canceled)