Patent ID: 8287249
Filing Date: 2012-10-16
Classification: F04B

Abstract:
1. A two-stage pump, comprising: a first pump head having a pump chamber and an inlet port and an outlet port, the inlet port having an inlet valve and the outlet port having an outlet valve; a second pump head having a pump chamber and an inlet port and an exhaust port, the inlet port of the second pump head being in direct connection of flow with the outlet port of the first pump head wherein the inlet port of second pump head does not include an inlet valve to regulate fluid flow in or out of the inlet port of second pump head, the exhaust port having an exhaust valve; a first and second flexible diaphragm each having a surface area suitable for sealing and unsealing the pumping chamber of each of the first pump head and second pump head respectively in pumping relationship; wherein, the action of the first and second diaphragms acting in pumping relation provide alternatively the opening and closing of the first pump head outlet port and second pump head inlet port; and wherein during an upstroke of the second flexible diaphragm, the second flexible diaphragm is configured to substantially seal the inlet port of the second pump head.