Booster pump with bypass valve integrally formed in gasket

A pump comprising:

• a housing including first and second housing sections;
• a gasket between the first and second housing sections;
• at a least one fastener for holding the first and second housing sections together;
• said housing having at least a first pumping chamber, an inlet, an inlet passage in the housing leading from the inlet to the pumping chamber, an outlet and an outlet passage in the housing leading from the pumping chamber to the outlet;
• a first pumping member movable in the pumping chamber on an intake stroke whereby a fluid from the inlet passage is drawn into the pumping chamber and a discharge stroke whereby fluid in the pumping chamber is discharged into the outlet passage;
• a drive for moving the pumping member on the intake and discharge strokes;
• an inlet check valve in the inlet passage;
• an outlet check valve in the outlet passage, each of said check valves including a movable valve element and a valve seat;
• said gasket forming a seal between the first and second housing sections;
• a bypass passage in said housing leading from a location in the outlet passage downstream of the outlet check valve to a location in the inlet passage upstream of the inlet check valve, said bypass passage including a bypass opening in the gasket;
• a bypass valve including a bypass valve seat in the bypass passage, a region of said gasket and a biasing member for biasing said region of the gasket against the bypass valve seat to close the bypass passage, said region of the gasket being responsive to fluid under pressure from the outlet passage exceeding a pressure for moving off of the bypass valve seat to open the bypass passage;
• and
• the biasing member located in a bore in the housing and the gasket including a raised seal ridge circumscribing said region of the gasket and sealing said bore.

A pump comprising:

• a housing including first and second housing sections;
• a gasket between the first and second housing sections;
• at least one fastener for holding the first and second housing sections together;
• said housing having at least a first pumping chamber, an inlet, an inlet passage in the housing leading from the inlet to the pumping chamber, an outlet and an outlet passage in the housing leading from the pumping chamber to the outlet, the outlet passage including an outlet chamber in the second housing section at least partially defined by the gasket;
• a first pumping member movable in the pumping chamber on an intake stroke whereby a fluid from the inlet passage is drawn into the pumping chamber and a discharge stroke whereby fluid in the pumping chamber is discharged into the outlet passage;
• a drive for moving the pumping member on the intake and discharge strokes;
• an inlet check valve in the inlet passage;
• an outlet check valve in the outlet passage, each of said check valves including a movable valve element and a valve seat;
• said gasket forming a seal between the first and second housing sections;
• a bypass passage in said housing leading from a location in the outlet passage downstream of the outlet check valve to a location in the inlet passage upstream of the inlet check valve, the bypass passage including a bypass opening in the gasket and a bypass passage section in the first housing section;
• and
• a bypass valve including a bypass valve seat on the first housing section in the bypass passage, a region of said gasket and a biasing member for biasing said region of the gasket against the bypass valve seat to close the bypass passage, said region of the gasket being responsive to fluid under pressure from the outlet passage exceeding a pressure for moving off of the bypass valve seat to open the bypass passage.