Membrane fluid pump

Abstract

A membrane fluid pump includes a rotatable drive shaft. The shaft is equipped with a number of eccentrics arranged axially along the shaft. The membrane fluid pump further comprises a set of connecting rods connected to each of the eccentrics. Each connecting rod is attached between one of the eccentrics on the shaft and a corresponding membrane so that each of the connecting rods is arranged to transfer a rotating movement of the shaft to a reciprocating movement pattern of the corresponding membrane. Each of the eccentrics and the connecting rods are arranged such that all of the membranes will reciprocate with a phase shift evenly distributed over a 360 degree rotation of the drive shaft, and wherein all of the eccentrics are rotationally offset to each other with an angle so that they are evenly distributed over a 360 degree rotation of the drive shaft.

1 . A membrane fluid pump comprising:
 a drive shaft rotatable within said membrane fluid pump,   a plurality of eccentrics arranged axially along the drive shaft,   a set of connecting rods being connected to each eccentric, wherein each connecting rod of said set of connecting rods is attached between one of said plurality of eccentrics on said drive shaft and a corresponding membrane, so that each of said connecting rods is arranged to transfer a rotating movement of said drive shaft to a reciprocating movement pattern of the corresponding membrane,   wherein each eccentric and said connecting rods are arranged such that all of said membranes will reciprocate with a phase shift evenly distributed over a 360 degree rotation of said drive shaft, and   wherein all of said eccentrics are rotationally offset to each other with an angle so that they are evenly distributed over a 360 degree rotation of said drive shaft.   
     
     
         2 . (canceled) 
     
     
         3 . The membrane fluid pump according to  claim 1 , wherein the connecting rods of each set of connecting rods are arranged to reciprocate from a same axial position along said drive shaft. 
     
     
         4 . The membrane fluid pump according to  claim 1 , wherein each of said eccentrics has a ball or a sleeve bearing between said drive shaft and said set of connecting rods attached to that eccentric. 
     
     
         5 . The membrane fluid pump according to  claim 1 , further comprising a pump head including an inlet valve and an outlet valve or a valve combining inlet and outlet valve functionality for each membrane fluid pump. 
     
     
         6 . The membrane fluid pump according to  claim 5 , where said each inlet valve and outlet valve are opening and closing by the fluid flow that the said membrane induces when moving in the reciprocating movement pattern. 
     
     
         7 . The membrane fluid pump according to  claim 5 , where said each inlet valve and outlet valve are opening and closing as an active mechanism. 
     
     
         8 . The membrane fluid pump according to  claim 5 , wherein opening and closing of each inlet valve and outlet valve is in response to a predetermined pressure difference threshold. 
     
     
         9 . The membrane fluid pump according to  claim 8 , including membrane inlets and outlets in communication with corresponding inlet and outlet valves, wherein the plurality of membrane inlets and outlets are connected such that the fluid pressure change produced by each of said reciprocating membranes contributes to the opening and closing of said inlet and outlet valves. 
     
     
         10 . A plurality of membrane fluid pumps according to claim l, wherein the drive shafts of at least two of the plurality of membrane fluid pumps are connected in series so as to increase the total number of membranes. 
     
     
         11 . The plurality of membrane fluid pumps according to  claim 10 , wherein the drive shafts of at least two of the plurality of membrane fluid pumps are connected in series by a gearbox to permit the drive shafts of the at least two of the plurality of membrane fluid pumps connected in series to have different rotational speeds. 
     
     
         12 . The membrane fluid pump according  claim 8 , wherein the flow rate of the membrane fluid pump is controlled by enabling and disabling opening and closing inlet and outlet valves of different membranes. 
     
     
         13 . The membrane fluid pump according to  claim 1 , wherein rotation of the drive shaft and the eccentrics arranged axially along the drive shaft produce a membrane stroke for respective membranes, and a flow rate of the membrane fluid pump is controlled by changing an offset of at least some eccentrics thereby changing a displacement volume for respective membrane strokes. 
     
     
         14 . The membrane fluid pump according to  claim 5 , wherein the pump head includes a pump head cavity and a flow rate of the membrane fluid pump is controlled by changing a dead volume of the pump head cavity. 
     
     
         15 . The membrane fluid pump according to  claim 9 , wherein at least one of the membrane inlets and outlets from all membranes are interconnected via a cavity so as to reduce interference between opening and closing of inlet valves and outlet valves in said pump heads.