Patent ID: 6948917

Claim:
A hydraulically actuated downhole pump comprising: a power piston vertically reciprocated in a power cylinder; a reversing valve carried with said power piston and serving, when in a first position, to direct fluid flow to force said piston upwardly in said cylinder and in a second position to provide bypass fluid flow to cause said piston to move downwardly in said cylinder; a pilot valve carried by said power piston and having an upper and a lower position and serving when in said lower position to direct fluid flow to move said reversing valve from said first to said second position; a probe fixedly secured relative to said cylinder and configured to move said pilot valve to said lower position when said piston reaches an upper limit of travel, wherein said probe includes a downwardly extending essentially closed conduit at its upper end and except for at least one orifice to control flow of hydraulic fluid as said piston reaches said upper limit of travel; a pump cylinder in fixed and in coaxial relationship to said power cylinder; a pump piston reciprocated within said power cylinder; a pump rod interconnecting said power piston and said pump piston; and valves actuated in response to movement of said pump piston to cause pumping of fluid.