Puming system

Abstract

A pump unit which includes a pipe, a flexible bladder inside the pipe, an operating volume between an outer surface of the bladder and an opposing inner surface of the pipe, a valve arrangement to introduce pressurised water into the operating volume and to allow pressurised water to flow from the operating volume and another valve arrangement to allow slurry to flow into the interior of the bladder as water is expelled from the operating volume and to—allow slurry to flow from the bladder when water is introduced into the operating volume.

1 . A pump unit comprising:
 an elongate tubular housing with an inner surface, an inner bore, a first end and an opposing second end,   an elongate flexible bladder of tubular form with an outer surface, an interior, an inlet, at one end of the bladder, to the interior, and an outlet, at an opposing end of the bladder, from the interior, wherein the bladder is positioned inside the bore with the bladder in sealing engagement with the housing at opposed ends of the bladder whereby the inlet is in communication with the first end of the housing, the outlet Is in communication with the second end of the housing and an operating volume of variable size is formed between the outer surface of the bladder and the opposing inner surface of the housing,   a port for an actuating fluid which is provided on the housing in communication with said operating volume,   an inlet non-return valve connected to the first end of the tubular housing,   an outlet non-return valve connected to the second end of the tubular housing,   a first control valve for controlling the flow of the actuating fluid through the port into the operating volume, and   a second control valve for controlling the flow of the actuating fluid from the operating volume through the port.   
     
     
         2 . The pump unit according to  claim 1 , wherein the elongate tubular housing is a pipe with opposing first and second ends which are flanged and opposing ends of the bladder are sealingly engaged with respective flanges at the first and second ends of the pipe. 
     
     
         3 . The pump unit according to  claim 1 , wherein the inlet non-return valve allows the medium which is to be pumped to move, under gravity action, into the interior of the bladder. 
     
     
         4 . The pump unit according to  claim 1 , wherein the outlet non-return valve is adapted to allow the medium which is pumped to pass, under pressure, into a discharge line. 
     
     
         5 . The pump unit according to  claim 1 , further comprising a bi-directional flow meter for metering the flow of the actuating fluid through the port. 
     
     
         6 . The pump unit according to  claim 5 , further comprising a controller which is connected to the flow meter and which monitors the volume of actuating fluid which flows into the operating volume, and out of the operating volume. 
     
     
         7 . The pump unit according to  claim 1 , further comprising a plurality of sensors at respective axially spaced locations on the tubular housing, each sensor providing a respective signal which indicates the proximity of the bladder to the respective location of the tubular housing. 
     
     
         8 . A Pumping apparatus comprising three pump units, each pump unit being according to  claim 1 , wherein the three pump units are mounted substantially parallel to each other on supporting structure, and wherein with the supporting structure on a level surface, the first ends of the tubular housings are elevated so that each housing then slopes downwardly over the length of the supporting structure towards the second end. 
     
     
         9 . The Pumping apparatus according to  claim 8 , wherein the first non-return valves and a first manifold are, in use, positioned so that they lie outside the supporting structure and the second non-return valves and a second manifold, in use, lie outside the supporting structure. 
     
     
         10 . A method of operating the pumping apparatus of  claim 8  wherein, in sequence:
 pumping a medium from a first pump unit and, at the same time, preparing a second pump unit for pumping, 
 pumping the medium from a third pump unit and the preparation of the second pump unit is completed. 
 preparing the first pump unit for pumping is 
 preparing the first pump unit is completed and the preparation of the third pump unit for pumping is commenced.