Patent ID: 8641386
Filing Date: 2014-02-04
Classification: E03F,F04F

Abstract:
1. A method of pumping a liquid with the aid of at least one operating tank ( 2 ) of a pneumatic positive pressure displacement pump ( 1 ), which occurs in a sequence of two phases: a filling phase, during which a liquid is admitted into the operating tank through a pneumatically controlled inflow valve ( 4 ) located on an inflow conduit ( 3 ) to displace gas from the operating tank until the operating tank is filled with the liquid; and a pumping phase during which the pneumatically controlled inflow valve located on the inflow conduit is closed, and then a compressed actuating gas is introduced into the operating tank, which causes an outflow return valve ( 6 ) located on an outflow conduit ( 5 ) connected to the operating tank to open and the liquid is displaced from the operating tank until the operating tank is empty of the liquid, wherein during the pumping phase the pneumatically controlled inflow valve ( 4 ) closure is controlled by the introduction of a control gas into the operating tank ( 2 ) of the pneumatic positive displacement pump ( 1 ) at a pressure lower than the pressure of the compressed actuating gas and lower than the hydrostatic pressure at the egress from the outflow return valve ( 6 ) located on the outflow conduit ( 5 ) but at a pressure higher than the hydrostatic pressure at the ingress into the pneumatically controlled inflow valve ( 4 ) located on the inflow conduit ( 3 ), which causes the pneumatically controlled inflow valve ( 4 ) to close.