Patent ID: 7390173

Claim:
A liquid well pumping arrangement comprising: a pair of adjacent downhole reciprocating pumps each having a barrel, a piston rod connected to a piston slidable within the barrel, and valve means adapted to cause liquid to flow from a lower inlet of the barrel to an upper outlet from the barrel when the piston is reciprocated in the barrel; said pumps including an upper pump and a lower pump, the upper pump barrel being located wholly above the barrel of the lower pump, with said upper pump barrel having a central axis which is off-set from a central axis of the lower pump barrel; wherein the central axis of the upper pump barrel lies within the boundaries of the lower pump barrel; first and second sucker rod means attached respectively to the piston rods of the upper pump and lower pump, said second sucker rod means including a pair of rods which are connected to the piston rod of the lower pump and which are spaced apart so as to straddle a portion of the upper pump barrel; a well head pumping mechanism for applying reciprocating movement to each of the sucker rod means to cause movement of the pistons; said well head pumping mechanism being arranged to reciprocate each of said sucker rod means at the same cyclic rate but with the motions of the first sucker rod means being out of phase with motions of the second sucker rod means by 180°; and wherein there is provided a single delivery tube connected to both of the outlets from the pump barrels such that, with the pumping mechanism operating, a substantially continuous flow of liquid can be produced from said delivery tube.