Patent ID: 7381035

Claim:
A device for use in dispensing a liquid, the device comprising: a pump housing having an inlet passageway with a valve seat, an outlet passageway, and a pumping chamber between said inlet passageway and said outlet passageway; a piston slidably disposed within said pump housing for movement in a first direction for admitting an amount of the liquid into said pumping chamber through said inlet passageway and in a second direction for pumping the amount of the liquid from said pumping chamber through said outlet passageway, said piston including a throughbore aligned with said valve seat; a shaft disposed in said throughbore for movement relative to said piston when said piston is moved in said first and second directions; a check valve in said outlet passageway, said check valve having a movable body that is in a continuously spring-biased condition to control flow in said outlet passageway as said piston is moved in said first and second directions; and a valve body coupled with said piston, said valve body being disengaged from said valve seat to open said inlet passageway for admitting the amount of liquid into said pumping chamber when said piston is moved in said first direction and being engaged with said valve seat to close said inlet passageway when said piston is moved in said second direction.