Patent ID: 8535018
Filing Date: 2013-09-17
Classification: F04F

Abstract:
1. A system for pumping liquid comprising: two liquid columns for reaching a body of liquid at their bottom, each liquid column comprising a liquid level detector and a unidirectional valve allowing liquid to flow upward; an upper conduit for sealably connecting to tops of the two liquid columns so as to form a continuous conduit between the unidirectional valves of the two liquid columns; a sealable gas valve for extracting gas from the upper conduit; an actuated conduit having ends connecting to each of the two liquid columns above their unidirectional valve, the actuated conduit comprising, at each end, a unidirectional valve allowing liquid to flow inward from each of the two columns, wherein the unidirectional valves of the actuated conduit are located on a different axis than the axis on which the unidirectional valves of the two liquid columns are arranged the actuated conduit further comprising, between its two unidirectional valves, a switched valve allowing liquid to flow out of the system from one end of the liquid columns at a time; and a controller connected to the liquid level detectors and to the sealable gas valve, for controlling the switched valve and the sealable gas valve so that