Pump

Abstract

A pump that has a cavity ( 13 ) in which is located a flexible membrane ( 14 ). An inlet ( 24 ) opens into the cavity ( 13 ) and is associated with a valve ( 27 ). A valve ( 28 ) is likewise provided in an outlet ( 25 ). Also opening into cavity ( 13 ) is a port ( 22 ) to which means for applying negative and positive pressures can be connected whereby the flexible membrane ( 14 ) can be moved to its two states corresponding to completion of inlet and exhaust of a pumping cycle.

1 . (canceled)  
   
   
       2 . (canceled)  
   
   
       3 . A pump as claimed in  claim 19  wherein the membrane is formed from an elastomeric material.  
   
   
       4 . A pump as claimed in  claim 3  wherein the membrane is formed from elastomeric sheet material.  
   
   
       5 . A pump as claimed in claims  19  wherein the membrane is damped between first and second sections, of the housing each housing section with one of the opposing surfaces having a cavity section such that when the housing sections are assembled to form the housing, the cavity with opposing surfaces is formed.  
   
   
       6 . A pump as claimed in  claim 19  wherein a pressure port opens into said cavity, said pressure port being connectable to a source or sources of positive and negative pressures.  
   
   
       7 . A pump as claimed in  claim 6  further including a device to cyclically apply the positive and negative pressures to the cavity to cause the membrane to move between the stable states.  
   
   
       8 . (canceled)  
   
   
       9 . A pump as claimed in  claim 5  wherein the housing sections are joined together and to clamp the membrane about a peripheral margin thereof.  
   
   
       10 . A pump as claimed in  claim 5  wherein the first housing section includes a recess into which the membrane is located, the peripheral dimensions of the membrane being greater than those of the recess whereby compressive forces are set up in the membrane when it is installed in the recess to thereby create the preset.  
   
   
       11 . A pump as claimed in  claim 6  wherein the second housing section includes a protruding portion which engages in the recess when the first and second housing sections are combined together, to cause the membrane to be clamped in place.  
   
   
       12 . A pump as claimed in  claim 19  further including a third housing section coupled to the second housing section, said third housing section including means for facilitating connection of inlet and outlet conduits for pumpable material.  
   
   
       13 . A pump as claimed in  claim 12  wherein the second and third housing sections include inlet and outlet openings and means for locating therein a valve element.  
   
   
       14 . A pump as claimed in  claim 13  wherein the valve element is a disk of flexible material.  
   
   
       15 . A pump as claimed in  claim 6  wherein the cavity is elongate and the pressure port is offset in the length of the cavity.  
   
   
       16 . A pump as claimed in claims  7  wherein the cavity is elongate and of curved cross-section.  
   
   
       17 . A pump as claimed in  claim 15  or  16  wherein the ends of the elongate cavity are complex curved.  
   
   
       18 . (canceled)  
   
   
       19 . a pump including a housing, a cavity with opposing surfaces, an inlet port opening into the cavity, an outlet port opening from the cavity, a pressure port connected to the cavity, a flexible membrane located within the cavity, the flexible membrane being mounted within the housing and a pre-set is applied to the flexible membrane such that the membrane adopts a first stable state in contact with one of the opposing surfaces of the cavity and can be caused to invert into a second stable state by the application of pressure to the cavity via the pressure port, the bi-stable membrane thereby being movable between the first and second stable states corresponding to completion of inlet and exhaust of a pumping cycle.  
   
   
       20 . A pump as claimed in  claim 7  wherein the clamping of the membrane creates further compressive forces in the membrane.