Patent ID: 7735563

Claim:
A pressure driven pumping system, comprising: a housing; a separating member disposed within a first bore of the housing to separate a process chamber from a working chamber, the separating member movable within the housing; and a rod member coupled to the separating member and extending into a reduced pressure chamber, the reduced pressure chamber being sealed from the working chamber and configured for sustaining a pressure less than a pressure in the working chamber; one or more working fluid ports passing through the housing to the working chamber; and one or more working fluid valves for controlling flow through the one or more working fluid ports, wherein the separating member comprises a first face exposed to a process fluid and a second face exposed to a working fluid, the first face having an effective area greater than an area of the second face, wherein the working chamber is sandwiched between the process chamber and the reduced pressure chamber such that the rod member extends through the entire working chamber; and wherein at least one of the working fluid ports is in fluid communication with a pump for passing working fluid into the working chamber.