Bladder pump for liquid sampling and collecting

A bladder-type fluid-actuated liquid pump adapted to be at least partially submerged in a liquid to be pumped, said pump comprising:

• a substantially tubular casing adapted to be immersed in the liquid, said casing having an upper end and a lower end;
• at least one liquid inlet provided at said lower end of said tubular casing;
• a top cap attached to said upper end of said casing, said top cap including a fluid communication port and a liquid outlet port;
• a fluid chamber inside said hollow casing for receiving a fluid under pressure therein, said fluid chamber being in fluid communication with said fluid communication port;
• a liquid chamber inside said hollow casing for receiving the liquid therein, said liquid chamber being in fluid communication with said liquid inlet and said liquid outlet port;
• an inlet check valve disposed between said liquid inlet and said liquid chamber for permitting one-way flow of the liquid therethrough from said inlet to said liquid chamber and for preventing back-flow of the liquid from said liquid chamber to said liquid inlet;
• an outlet check valve disposed between said liquid outlet port and said liquid chamber for permitting one-way flow of the liquid therethrough from said liquid chamber to said liquid outlet port and for preventing back-flow of the liquid from said liquid outlet port to said liquid chamber;
• a flexible bladder separating said fluid chamber from said liquid chamber, said bladder being selectively deformable in response to changes in pressure of the fluid in order to cause the liquid to flow through said liquid chamber from said liquid inlet to said outlet;
• a top bladder mandrel secured to said top cap, said top bladder mandrel having a communication passage therethrough for fluidly connecting said liquid chamber to said liquid outlet port in said top cap;
• a mandrel sealing member disposed in said lower end of said casing and defining an inlet chamber within said lower end of said casing, said inlet chamber being in fluid communication with said at least one liquid inlet, said mandrel sealing member sealingly separating said liquid chamber from said inlet chamber;
• a bottom bladder mandrel secured to said mandrel sealing member, said bottom bladder mandrel having a communication passage therethrough for fluidly connecting said liquid chamber to said inlet chamber;
• and
• a support member extending between said top and bottom mandrel inside said bladder,
• wherein said bladder being sealingly secured to said top bladder mandrel at one end and to said bottom bladder mandrel at the other end, and wherein said liquid chamber is enclosed within said flexible bladder.