Patent ID: 6988332
Filing Date: 2006-01-24
Classification: A01G

Abstract:
1. An air driven liquid pump for pumping a target volume of liquid emanating from a liquid inlet duct into a liquid outlet duct, both said liquid inlet and outlet ducts being subjected to at least a partial air vacuum, said liquid inlet and outlet ducts being fluidly coupled together respectively upstream from said liquid pump and downstream from said liquid pump by a by-pass duct extending therebetween, said liquid pump comprising: a reservoir having a reservoir wall enclosing a reservoir chamber; a liquid inlet aperture extending through said reservoir wall for fluid coupling to said liquid inlet duct; a liquid outlet aperture extending through said reservoir wall for fluid coupling to said liquid outlet duct, said liquid outlet aperture being in fluid communication with an outlet level inside said reservoir chamber located below said liquid inlet aperture and corresponding to a predetermined lower threshold value of the volume of said liquid within said reservoir chamber; an air aperture extending through said reservoir wall for pneumatically coupling said reservoir chamber with the atmospheric air located exteriorly to said reservoir; a liquid inlet valve operationally coupled to said liquid inlet aperture, said liquid inlet valve being operable between a liquid valve open configuration and a liquid valve closed configurations for respectively allowing and preventing the flow of a fluid through said liquid inlet aperture; an air valve operatively coupled to said air aperture, said air valve being operable between an air valve open configuration and an air valve closed configurations for respectively allowing and preventing the flow of air through said air aperture; a volume responsive first actuating means for selectively moving said liquid inlet valve to said liquid valve closed configuration and said air valve to said air valve open configuration upon the volume of liquid within said reservoir reaching a predetermined upper threshold value; a volume and pressure responsive second actuating means for selectively moving said liquid inlet valve to said liquid valve open configuration and said air valve to said air valve closed configuration upon the volume of liquid within said reservoir reaching said predetermined lower threshold value and the pressure differential between the air pressure inside and outside said reservoir reaching a predetermined differential threshold; whereby with said liquid inlet valve in said liquid valve open configuration and said air valve in said air valve closed configuration said liquid is allowed to flow into said reservoir chamber for filling the latter while the pressure inside said reservoir chamber is lowered by said at least partial air vacuum at a level lower then that of the atmospheric pressure outside said reservoir so as to create a pressure differential therebetween, when the volume of liquid within said reservoir chamber reaches said predetermined upper threshold value said first actuating means when the volume of liquid inside said reservoir chamber falls to said lower threshold value, the air now allowed to flow out of the reservoir chamber through said liquid outlet aperture lowers the pressure inside said reservoir chamber to said predetermined differential threshold allowing said second actuating means to move said liquid inlet valve to said liquid valve open configuration and said air valve to said air valve closed configuration for a new cycle to begin.