Peristaltic pump with linear flow control

Abstract

A peristaltic pump includes a conduit having a first end tor receiving a fluid from a reservoir and a second end for delivering the fluid. A plurality of fingers are disposed at respective locations along a segment of the conduit and are configured to alternately compress and release the conduit at the locations. A cyclical pump mechanism is coupled to move the fingers between respective compressed and released positions in a spatio-temporal pattern so as to drive a predetermined quantity of the fluid through the segment of the conduit in each pump cycle. A motor is coupled to drive the pump mechanism. A controller is coupled to activate and deactivate the motor in alternation during each pump cycle with a duty cycle that varies within the pump cycle.

1 . A fluid pump comprising:
 An electrical motor to convert an electrical signal into a mechanical rotation of a shaft, such that an instantiations rotational velocity of said shaft corresponds to an instantaneous parameter of the electrical signal applied to said motor;   a fluid pumping mechanism driven by said shaft such that a rotation of said shaft causes said pumping mechanism to force some volume of fluid flow through a functionally associated fluid conduit, wherein the pumping mechanism is characterized by non-uniform shaft rotation to fluid volume function across different angles of a full shaft rotation cycle (e.g. 360 deg), such that a given rotation angle (e.g. 0.33 deg) of said shaft starting at a first shaft angles results in a different fluid flow than the same given rotation angle starting at a second shaft angle;   a sensor adapted to detect one or more parameters relating to an instantaneous position of said shaft within the full shaft rotation cycle; and   a variable electrical signal source to receive an output of said sensor and in response to generate a non-uniform electrical signal with at least one electrical parameters being a function of a sensed instantaneous position of said shaft, wherein the sources generates a non-uniform electrical signal which compensates for the non-uniform shaft rotation to fluid volume function across different angles of a full shaft rotation cycle.   
     
     
         2 . The pump according to  claim 1 , wherein said sensor is an angular encoder. 
     
     
         3 . The pump according to  claim 1 , wherein said variable signal source includes a micro-controller. 
     
     
         4 . The pump according to  claim 3 , wherein said variable signal source includes a shaft rotation angle to instantaneous electrical signal parameter converter. 
     
     
         5 . The pump according to  claim 4 , wherein said variable signal source includes one or more of:
 (a) a digital to analog converter; (b) an electrical amplifier, and (c) a power sources.   
     
     
         6 . The pump according to  claim 1 , wherein the instantaneous parameter of the electrical signal applied to said motor is a pulse rate. 
     
     
         7 . The pump according to  claim 1 , wherein the instantaneous parameter of the electrical signal applied to said motor is a voltage. 
     
     
         8 . The pump according to  claim 1 , wherein the fluid pumping mechanism includes three or more compressing elements placed in a linear arrangement relative to one another, and wherein each compressing element is configured to cyclically compress and release a separate cross-section of the fluid conduit at different angles along the full rotation cycle of said shaft.