Pumping chamber movement activated downhole pneumatic pump

Abstract

A floatless pneumatic pump having an elongated housing including a sealable fluid entry aperture and a pipe communicating between an interior and an exterior of the housing, with the housing movably attached to the pipe for axial displacement therewith. The housing includes a bottom wall and a cylindrical side wall extending from the bottom wall and terminating in an opening. A switchable valve control having a pod closes the opening. The pod has a plurality of valve seats and a plurality of corresponding valve elements, with the plurality of valve seats defining at least one fluid inlet port and at least one fluid outlet port. The valve elements alternatingly seal the inlet and outlet ports in relation to the axial displacement of the housing, allowing both fluid to ingress through a sealable fluid entry aperture and fluid to egress through the pipe. Another embodiment includes a variable buoyant actuator coupled to the pod to alternatingly place the valve elements in sealing engagement with the inlet and outlet ports in response to a level of fluid in the housing. The variable buoyant actuator includes a neutral density weight disposed proximate to the bottom wall, and a buoyant amplifier, disposed opposite to the neutral density weight, proximate to the pod. In this manner, the use of a float may be obviated or a float of substantially reduced volume may be employed.