The invention relates to a positive displacement pump (10) comprising a pump body (11, 101, 201) comprising an inlet end (16, 116, 216) and an outlet end (18, 118, 218), a pumping chamber (30, 130, 230) arranged between said inlet end (16, 116, 216) and said outlet end (18, 118, 218), at least one membrane (20, 120, 220) active in the pumping chamber (30, 130, 230) and mobile between an expanded configuration in which the volume of the pumping chamber (30, 130, 230) is maximum and a retracted configuration in which the volume of the pumping chamber (30, 130, 230) is minimum, a delivery valve (46, 146, 246) arranged close to the outlet end (18, 118, 218) of the pump body (11, 101, 201), an intake valve (26, 126, 226) comprising an intake mouth (27, 127, 227), an outlet mouth (28, 128, 228) and a valve wall (29, 129, 229) that joins the intake mouth (27, 127, 227) to the outlet mouth (28, 128, 228), the intake mouth (27, 127, 227) being coupled to the inlet end (16, 116, 216) of the pump body (11, 101, 201) and the outlet mouth (28, 128, 228) being inserted in the pumping chamber (30, 130, 230). Said at least one membrane (20, 120, 220), when in the retracted configuration, adheres to the valve wall (29, 129, 229) of the intake valve (26, 126, 226) and the intake valve has the outlet mouth closed.

The invention relates to a positive displacement pump (10) comprising a pump body (11, 101, 201) comprising an inlet end (16, 116, 216) and an outlet end (18, 118, 218), a pumping chamber (30, 130, 230) arranged between said inlet end (16, 116, 216) and said outlet end (18, 118, 218), at least one membrane (20, 120, 220) active in the pumping chamber (30, 130, 230) and mobile between an expanded configuration in which the volume of the pumping chamber (30, 130, 230) is maximum and a retracted configuration in which the volume of the pumping chamber (30, 130, 230) is minimum, a delivery valve (46, 146, 246) arranged close to the outlet end (18, 118, 218) of the pump body (11, 101, 201), an intake valve (26, 126, 226) comprising an intake mouth (27, 127, 227), an outlet mouth (28, 128, 228) and a valve wall (29, 129, 229) that joins the intake mouth (27, 127, 227) to the outlet mouth (28, 128, 228), the intake mouth (27, 127, 227) being coupled to the inlet end (16, 116, 216) of the pump body (11, 101, 201) and the outlet mouth (28, 128, 228) being inserted in the pumping chamber (30, 130, 230). Said at least one membrane (20, 120, 220), when in the retracted configuration, adheres to the valve wall (29, 129, 229) of the intake valve (26, 126, 226) and the intake valve has the outlet mouth closed.

A reciprocating fluid pump includes a pump body, a first subject fluid chamber, a second subject fluid chamber, a first plunger at least partially defining a first drive fluid chamber and including a flexible material and configured to expand and compress in a reciprocating action to pump the subject fluid through the first subject fluid chamber within the pump body, and a second plunger located within the pump body and at least partially defining a second drive fluid chamber and including a flexible material and configured to expand and compress in a reciprocating action to pump the subject fluid through the second subject fluid chamber within the pump body, wherein the first plunger is not structurally coupled to the second plunger, such that the first plunger and the second plunger are independently movable during operation.