Pump apparatus for fluid sampling and collection, and the like

A gas-actuated liquid pump adapted to be at least partially submerged within a liquid to be pumped, said liquid pump comprising:

• a pump body, a liquid inlet, a liquid outlet, a gas chamber in said pump body for receiving a gas therein, a liquid chamber in said pump body in fluid communication with said liquid to be pumped longitudinally through said inlet, a flexible bladder isolating said gas chamber form said liquid chamber, said flexible bladder being selectively deformable in response to changes in the pressure of said gas in order to cause said liquid to flow through said liquid chamber from said inlet to said outlet, inlet check valve means between said inlet and said liquid chamber for allowing one-way flow of said liquid therethrough from said inlet to said liquid camber and for substantially preventing back-flow of said liquid therethrough from said liquid chamber to said inlet regardless of the vertical, horizontal, non-vertical, or inverted orientation of said pump, outlet check valve means between said outlet and said liquid chamber for allowing one-way flow of said liquid therethrough from said liquid chamber to said outlet and for substantially preventing back-flow of said liquid therethrough from said outlet to said liquid chamber regardless of the vertical, horizontal, non-vertical, or inverted orientation of said pump, and anti-chafe means generally surrounding said flexible bladder and disposed between said flexible bladder and the interior of said pump body for substantially preventing contact of said flexible bladder with said pump body, each of said inlet and outlet check valve means including a reed-type check valve member having a body portion having an internal flow opening extending therethrough, a flange portion at one end of said body portion surrounding said internal flow opening in sealing engagement with said pump adjacent said inlet, and a lip portion at the opposite end of said body portion resiliently deflectable between an open position in communication with said internal flow opening for allowing said one-way flow therethrough and a closed position blocking off said internal flow opening for substantially preventing said back-flow therethrough, said lip portion being resiliently biased toward said closed position, said lip portion being resiliently deflectable to said open position in response to a predetermined liquid pressure within said internal flow opening, said lip portion being further biased toward said closed position by a back-pressure exerted thereon from within said liquid camber, said reed-type check valve member including a generally frusto-conical tapered portion converging toward said opposite end of said body portion and defining said lip portion at said opposite end, said anti-chafe means including an anti-chafe sleeve disposed between said flexible bladder and the interior of said pump body in a laterally generally-surrounding relationship with sad flexible bladder, said anti-chafe sleeve having at least one open unsecured end portion thereon providing fluid communication between the interior of said anti-chafe sleeve and said gas chamber.