Patent ID: 7275590

Claim:
A submersible pump for connection to a discharge tube having a lower end including an entrance; said pump for pumping a liquid into the entrance of the discharge tube; said pump including: a wet portion for disposition in the liquid including: a collecting tuba defining a collection chamber for collecting the liquid; said collecting tube including: an upper end; and a lower end including: a collection port for ingress of the liquid into said collection chamber; and a collection valve having open and closed positions that open and close said collection port; and a pumping tube for pumping the liquid; said pumping tube defining a lifting chamber; said pumping tube having a longitudinal axis and including: an upper end including an egress orifice for ingress of lifted liquid into the discharge tube; a lower end including: an ingress port for ingress of liquid from said collection chamber; and an ingress valve having open and closed positions that open and close said ingress port; said pumping tube adapted for reciprocating, longitudinal, sealed, and sliding lifting and pushing movements with the discharge tube and with said collecting tube; the lifting movement being from a lower position, wherein said pumping tube lower end is within said collecting tube and distal the entrance of the discharge tube and said ingress valve is closed, to an upper position, wherein said pumping tube lower end is proximal the entrance of the discharge tube, such that liquid within said lifting chamber is lifted into the entrance of the discharge tube and liquid flows into said collection chamber through said collection port; the pushing movement being from the upper position, wherein said collection valve is closed, to the lower position such that, due to displacement by said pumping tube, a first volume of liquid is forced from said collection chamber through said ingress port, through said pumping tube, and into the entrance of the discharge tube and a second volume of liquid from said collection chamber passes through said ingress port into said lifting chamber; and reciprocating means fix reciprocating said pumping tube.