Uniform flow displacement pump

Abstract

A displacement pump comprising a pump assembly and a cassette assembly. The pump assembly includes upper and lower housing portions that define a cavity, an arm disposed in the cavity, a roller attached to the distal end of the arm, and a motor attached to the proximal end of the arm for rotating the arm. The cassette assembly is removably disposed in the cavity and comprises upper and lower cassette housing portions that form an annular compression surface with a channel therein. A hollow compression tube having a flange extending along a length thereof is secured to the compression surface by the flange being engaged with the channel. As the motor rotates the roller arm, the roller presses the compression tube against the compression surface to create a moving occlusion of the compression tube for pushing fluid through the compression tube.

1 . A pump, comprising: 
 a compression surface;    a hollow compression tube secured to the compression surface;    compression means for incrementally compressing the compression tube against the compression surface to create a moving occlusion of the compression tube that uniformly pushes fluid through the compression tube, wherein the compression means has at least one rest position in which the compression means is free of all contact with the compression tube in a manner such that the compression tube is free of any occlusions; and    wherein: 
 a channel is formed in the compression surface,  
 the hollow compression tube includes a flange extending along a length thereof that is engaged with the channel for securing the compression tube to the compression surface, and  
 the flange is cylindrically shaped and integrally formed with the compression tube.  
   
   
   
       2 . The pump of  claim 1 , wherein the compression means is a single roller that rolls along the compression tube.  
   
   
       3 . The pump of  claim 2 , wherein: 
 the compression surface is annularly shaped; and    the single roller rotates about a fixed point.    
   
   
       4 . The pump of  claim 2 , wherein: 
 the compression surface is elliptically shaped; and    the single roller is mounted to a spring loaded arm that rotates about a fixed point.    
   
   
       5 . The pump of  claim 4 , wherein as the spring loaded arm rotates through a complete revolution about the fixed point, the single roller disengages from the compression tube at least twice.  
   
   
       6 . The pump of  claim 1 , wherein: 
 the compression means is a plurality of rollers that roll along the compression tube; and    no more than one of the plurality of rollers compresses the compression tube at any given time.    
   
   
       7 . The pump of  claim 1 , further comprising: 
 a pump housing that defines a cavity, wherein the compression means is disposed in the cavity; and    a cassette assembly removably disposed in the cavity, wherein the cassette assembly includes the compression surface and the hollow compression tube.    
   
   
       8 . The pump of  claim 1 , wherein the compression means includes a second rest position in which the compression means forms a temporary pinch-valve by temporarily stalling the moving occlusion of the compression tube.  
   
   
       9 . A pump, comprising: 
 a pump assembly that includes: 
 a pump housing that defines a cavity,  
 a roller disposed in the cavity, and  
 a motor for moving the roller relative to the housing;  
   a cassette assembly removably disposed in the cavity and including: 
 a cassette housing having a compression surface, and  
 a hollow compression tube secured to the compression surface;  
   wherein as the motor moves the roller, the roller presses the compression tube against the compression surface to create a moving occlusion of the compression tube for pushing fluid through the compression tube, and wherein the roller has a rest position where the roller does not contact the compression tube and the compression tube is free of any occlusions;    wherein: 
 a channel is formed in the compression surface,  
 the hollow compression tube includes a flange extending along a length thereof that is removably engaged with the channel for securing the compression tube to the compression surface, and  
 the flange is cylindrically shaped and integrally formed with the compression tube.  
   
   
   
       10 . The pump of  claim 9 , further comprising: 
 an arm disposed in the cavity and including a proximal end and a distal end, wherein the roller is attached to the distal end of the arm and the motor is attached to the proximal end of the arm.    
   
   
       11 . The pump of  claim 10 , wherein the arm is spring loaded for applying pressure on the compression tube by the roller.  
   
   
       11 . The pump of  claim 10 , wherein the arm has a rest rotational position where the roller does not contact the compression tube.  
   
   
       13 . The pump of claim  12 , wherein the arm has a second rest rotational position where the roller forms a temporary pinch-valve by temporarily stalling the moving occlusion of the compression tube.