Pig pumping unit

Abstract

A pumping unit is provided that allows at least four passes to be made simultaneously with a single pumping unit. A single engine is used to drive two pumps, each connected into separate pumping circuits. Fluid flow in each of the pumping circuits is controlled by respective flow control elements on the pumping circuits, as for example a variable flow valve. Two engines may thus be used to drive four pumps.

1 . A multipass pig pumping unit, comprising:
 a trailer   one or more clean water tanks on the trailer;   one or more dirty water tanks on the trailer;   at least a first engine on the trailer, the first engine connected to drive a first pump and to drive a second pump;   the first pump having at least a first inlet and a first power outlet, the first inlet being connected to receive water from at least one of the one or more clean water tanks;   the second pump having at least a second inlet and a second power outlet, the second inlet being connected to receive water from at least one of the one or more clean water tanks;   a first valved pumping circuit connected to receive pig drive fluid from the first power outlet and including a first return conduit connected to return pig drive fluid to at least one of the one or more dirty water tanks, the first valved pumping circuit having connections for connecting a first pipe to be cleaned into the first valved pumping circuit;   a second valved pumping circuit connected to receive pig drive fluid from the second power outlet and including a second return conduit connected to return pig drive fluid to at least one of the one or more dirty water tanks, the second valved pumping circuit having connections for connecting a second pipe to be cleaned into the second valved pumping circuit;   a first variable flow control element on the first valved pumping circuit;   a second variable flow control element on the second valved pumping unit; and   a second engine on the trailer, the second engine connected to drive a third pump;   the third pump having at least a third inlet and a third power outlet, the third inlet being connected to receive water from at least one of the one or more clean water tanks;   a third valved pumping circuit connected to receive pig drive fluid from the third power outlet and including a third return conduit connected to return pig drive fluid to at least one of the one or more dirty water tanks, the third valved pumping circuit having connections for connecting a third pipe to be cleaned into the third valved pumping circuit; and   a third variable flow control element on the third valved pumping circuit.   
     
     
         2 . The pig pumping unit of  claim 1  in which:
 the at least a first engine is located in an engine compartment; 
 the one or more clean water tanks comprise at least a first clean water tank connected to the first inlet and a second clean water tank connected to the second inlet; and 
 the first clean water tank and die second clean water tank are located on opposite sides of the engine compartment. 
 
     
     
         3 . The pig pumping unit of  claim 1  in which:
 the first variable flow control element is a first valve is located on the first return conduit; and 
 the second variable flow control element is a second valve is located on the second return conduit. 
 
     
     
         4 . The pig pumping unit of  claim 3  in which:
 the at least a first engine is located in an engine compartment; 
 the one or more clean water tanks comprise at least a first clean water tank connected to the first inlet and a second clean water tank connected to the second inlet; and 
 the first clean water tank and the second clean water tank are located on opposite sides of the engine compartment. 
 
     
     
         5 - 10 . (canceled)