Solenoid pump

Abstract

A solenoid pump for moving a fluid is disclosed. The pump includes a solenoid coil that generates an electromagnetic field for moving a plunger relative to a stationary core. Magnetic components of the solenoid pump direct the electromagnetic field to provide a substantially balanced magnetic force on the plunger.

1 . A solenoid pump comprising:
 a body having a fluid inlet and a fluid outlet and a fluid conduit connecting the fluid inlet and the fluid outlet;   a reciprocating member supported by the body and moveable along an axis between a first position and a second position, the reciprocating member moving fluid received from the fluid inlet on towards the fluid outlet during a movement between the first position and the second position;   an electromagnetic coil configured to generate an electromagnetic field to move the reciprocating member from the first position to the second position; and   a pole piece positioned radially outwardly from the coil for directing the electromagnetic field generated by the coil, the pole piece being substantially symmetrical relative to the axis to provide a substantially balanced magnetic force on the reciprocating member with respect to the axis.   
     
     
         2 . The solenoid pump of  claim 1 , further comprising a pole extension positioned at least partially between the pole piece and the reciprocating member, the pole extension bridging the electromagnetic field between the pole piece and the reciprocating member. 
     
     
         3 . The solenoid pump of  claim 2 , further comprising a stationary core positioned at least partially within the electromagnetic coil and having a fluid conduit in fluid communication with the fluid inlet and the fluid outlet. 
     
     
         4 . The solenoid pump of  claim 3 , wherein the reciprocating member, the pole piece, the pole extension, and the stationary core are made of stainless steel. 
     
     
         5 . The solenoid pump of  claim 3 , further comprising a first valve positioned within a cavity of the reciprocating member and a second valve positioned between the stationary core and the fluid outlet, the first valve and the second valve cooperating to regulate the flow of fluid from the fluid inlet to the fluid outlet. 
     
     
         6 . The solenoid pump of  claim 5 , wherein the first valve is a duckbill valve and the second valve is a poppet valve. 
     
     
         7 . The solenoid pump of  claim 3 , further comprising a seal providing a radial sealing surface around the circumference of the reciprocating member, the reciprocating member being movable relative to the seal. 
     
     
         8 . The solenoid pump of  claim 7 , wherein the seal is one of a rod seal and a ramped seal. 
     
     
         9 . The solenoid pump of  claim 7 , further comprising a sleeve positioned between the stationary core and the pole extension and received within the electromagnetic coil, the sleeve cooperating with the pole extension and the seal to form a sealed travel path for the reciprocating member. 
     
     
         10 . The solenoid pump of  claim 3 , further comprising a first stop and a second stop each configured to limit the travel of the reciprocating member, the first stop limiting movement of the reciprocating member away from the stationary core and the second stop limiting movement of the reciprocating member towards the stationary core. 
     
     
         11 . The solenoid pump of  claim 10 , wherein the first and second stops each include a wave spring washer and at least one of an elastomeric washer and a metal washer. 
     
     
         12 . The solenoid pump of  claim 10 , wherein the reciprocating member includes a magnetic body portion coupled to a nonmagnetic end piece, the end piece including a flanged portion for engaging the first and second stops. 
     
     
         13 . The solenoid pump of  claim 10 , further comprising a washer coupled between the stationary core and the reciprocating member and configured to cooperate with the second stop to limit movement of the reciprocating member towards the stationary core. 
     
     
         14 . The solenoid pump of  claim 10 , further comprising a spring positioned between the stationary core and the reciprocating member for biasing the reciprocating member towards the first stop. 
     
     
         15 . The solenoid pump of  claim 14 , wherein the solenoid coil is energized by a half-wave rectified AC current signal, wherein when the solenoid coil is energized the electromagnetic field pulls the reciprocating member towards the stationary core and when the solenoid coil is de-energized the spring pushes the reciprocating member away from the stationary core. 
     
     
         16 . The solenoid pump of  claim 3 , wherein the reciprocating member includes an end having a tapered outer surface and the stationary core includes a receiving end having a tapered inner surface configured to cooperate with the tapered outer surface of the reciprocating member, wherein the end of the reciprocating member is received within the receiving end of the stationary core as the reciprocating member moves towards the stationary core. 
     
     
         17 . The solenoid pump of  claim 16 , wherein the end of the reciprocating member includes an inner opening for receiving a spring, the spring extending between the end of the reciprocating member and the receiving end of the stationary core for biasing the reciprocating member away from the stationary core. 
     
     
         18 . The solenoid pump of  claim 1 , wherein the pole piece is constructed of a plurality of metal layers and a viscoelastic bonding material coupled to at least one of the metal layers. 
     
     
         19 . The solenoid pump of  claim 1 , wherein the solenoid pump is configured to move a heat exchange fluid through a heat exchange system. 
     
     
         20 . The solenoid pump of  claim 1 , wherein the solenoid pump is configured to deliver water to a heating element of a steam device. 
     
     
         21 . The solenoid pump of  claim 1 , wherein the solenoid pump is configured to advance a drink product towards a dispenser of a drink dispensing device. 
     
     
         22 . The solenoid pump of  claim 1 , wherein the solenoid pump is configured to provide water to a chamber of a coffee machine. 
     
     
         23 - 51 . (canceled)