Volumetric Infusion Pump and Method

Abstract

In a first embodiment, an electromagnetic pump has a housing including first and second spaced apart electromagnets. A controller for controlling the magnets and a power source for powering the electromagnets within the housing. A removable cassette is in engagement with the housing between the first and second electromagnets and includes a cavity. The pump also has inlet and outlet ports in communication with the cavity and a magnetic piston disposed within the cavity. In preferred embodiments the electromagnets are capable of operating at different strengths and different polarities.

1 . A electromagnetic pump comprising:
 a housing including first and second spaced apart electromagnets;   a controller for controlling the magnets within the housing;   a power source for powering the electromagnets within the housing;   a cassette in engagement with the housing between the first and second electromagnets and including a cavity;   an inlet port in communication with the cavity;   an outlet port in communication with the cavity; and   a magnetic piston disposed within the cavity.   
   
   
       2 . The electromagnetic pump of  claim 1  wherein the cassette is removable. 
   
   
       3 . The electromagnetic pump of  claim 1  wherein the piston is movable between a first open position and a second closed position. 
   
   
       4 . The electromagnetic pump of  claim 3  wherein the inlet port is part of the removable cassette. 
   
   
       5 . The electromagnetic pump of  claim 4  wherein the outlet port is part of the removable cassette. 
   
   
       6 . The electromagnetic pump of  claim 5  wherein the magnetic piston includes a piston body and a Neodymium magnet. 
   
   
       7 . The electromagnetic pump of  claim 5  wherein the cavity is on a first side of the piston and the piston includes an extension defining a passage on a second side of the piston, the cassette further including a sterile vent in communication with the passage. 
   
   
       8 . The electromagnetic pump of  claim 5  wherein the cassette further includes a flexible barrier disposed within the cavity. 
   
   
       9 . The electromagnetic pump of  claim 5  wherein the inlet port includes a one-way flapper valve. 
   
   
       10 . The electromagnetic pump of  claim 9  wherein the outlet port includes a one-way flapper valve. 
   
   
       11 . The electromagnetic pump of  claim 1  wherein the electromagnets are capable of operating at different strengths and different polarities. 
   
   
       12 . The electromagnetic pump of  claim 3  further comprising a first sensing device capable of detecting when the piston is in the closed position. 
   
   
       13 . The electromagnetic pump of  claim 12  further comprising a second sensing device capable of detecting when the piston is in the open position. 
   
   
       14 . The electromagnetic pump of  claim 13  wherein the first and second sensing devices are LED sensors and the cassette is capable of reflecting light from the LED sensors back to the LED sensors. 
   
   
       15 . The electromagnetic pump of  claim 3  wherein the default position of the piston is in the closed position. 
   
   
       16 . A method of dispensing a liquid, the method comprising the steps of:
 providing an electromagnetic pump including;
 a housing including first and second spaced apart electromagnets, 
 a controller for controlling the magnets within the housing, 
 a power source for powering the electromagnets within the housing, 
 a cassette in engagement with the housing between the first and second electromagnets and including a cavity, 
 an inlet port in communication with the cavity, 
 an outlet port in communication with the cavity, 
 a magnetic piston disposed within the cavity; 
   supplying a liquid to be dispensed to the inlet port;   powering the electromagnets to draw the piston into an open position thereby drawing the liquid through the inlet port and into the cavity; and   powering the electromagnets to draw the piston into a closed position thereby pushing the liquid out of the cavity and through the outlet port.   
   
   
       17 . The method of  claim 16  further including the step of providing free-flow protection against liquid flowing back through the inlet port. 
   
   
       18 . The method of  claim 17  wherein the free-flow protection is provided by the controller controlling the piston to default to the closed position. 
   
   
       19 . The method of  claim 16  further including the step of sensing the position of the piston within the cavity. 
   
   
       20 . The method of  claim 19  where the housing includes a sensor for reading the location of the piston. 
   
   
       21 . The method of  claim 20  wherein the sensor is an LED. 
   
   
       22 . The method of  claim 18  further including the step of calculating the volume of liquid delivered via movement of the piston. 
   
   
       23 . The method of  claim 22  wherein after the step of powering the second electromagnet to draw the piston into a second position thereby pushing the liquid out of the cavity and through the outlet port, the second electromagnet is depowered, thereby allowing a cycle of powering the first electromagnet, depowering the first electromagnet, and powering the second electromagnet is capable of being repeated plurality of times, the method further including the step of:
 calculating the total volume of liquid delivered via the plurality of cycles.   
   
   
       24 . The method of  claim 23  wherein the steps of calculating are performed by the controller. 
   
   
       25 . The method of  claim 16  wherein the cassette is removeable. 
   
   
       26 . The method of  claim 25  further including the step of sensing for the presence of the removable cassette in the pump. 
   
   
       27 . The method of  claim 23  wherein the movement of the piston between the open and closed positions is at a velocity, the method further comprising the step of varying the velocity of the piston to control a rate of delivery. 
   
   
       28 . The method of  claim 27  wherein the velocity is varied by comparing a required delivery rate to an actual delivery rate where the actual delivery rate is determined by sensing the position of the piston within the cavity.