Abstract: An alternative piston pump employed in mechanical pumping systems for oil extraction. The alternative piston pump includes a case part having at least one cavity disposed along its inner surface. Thus, during the pumping cycle, a gas transfer from a bottom chamber to the case part above a piston and an oil transfer from the case part above the piston to the bottom chamber is established.

Abstract: The actual patent refers to an invention for alternative piston pump (40) improvement, and particularly to an alternative piston pump (40) improvement employed in mechanical pumping systems for oil extraction, aiming to solve the shutdown on gas in fluid elevation draining problem. The proposed improvement is characterized by the alternative piston pump (40) case (41) to be provided with at least one cavity (46) disposed along its inner surface (411). Thus, during the pumping cycle, a gas transfer from bottom chamber (45) to the case part (41) above piston (42) and an oil transfer from the case part (41) above the piston (42) to the bottom chamber (45) is established. Therefore solving the shutdown on gas in fluid elevation draining problem, for oil extraction mechanical pumping systems.