Dual chamber liquid pump

Abstract

The fluid pump of the present invention includes an upper enclosure for holding fluid (typically a liquid) from a fluid input source, and a lower enclosure for outputting the fluid to an output line. A first valve (a) controls the fluid input flow into the upper enclosure. A second valve (b) is engaged in a line between the upper enclosure and the lower enclosure to control the fluid flow from the upper enclosure to the lower enclosure. A second fluid input line is engaged to the lower enclosure to input a second fluid (typically a pressurized gas) into the lower enclosure, and a third valve (d) is engaged in a line between the lower enclosure and upper enclosure to control the flow of the second fluid into the second enclosure. A fourth valve (c) is engaged in a fluid output line to control the flow of the second fluid out of the upper enclosure. In the preferred embodiments, each of valves a, b, c and d is controlled by an automated pump system controller. Various embodiments of the present invention include further valves and check valves to provide improved control in the system. The preferred embodiment of the dual chamber pump operates by outputting the liquid from the lower enclosure under a constant, controlled gas pressure. When the liquid level in the lower enclosure is low, the lower enclosure is filled with liquid from the upper enclosure. To accomplish this, the upper enclosure is pressurized to the same pressure as the lower enclosure, and because the upper enclosure is disposed above the enclosure, the gravitational head causes the liquid in the upper enclosure to flow into the lower enclosure. The upper enclosure is filled during the pump cycle in which the lower enclosure is outputting liquid. The pump thus has a repeatable cycle, although the gas pressure in the lower enclosure remains constant and liquid is constantly output from the pump at a controlled pressure.