Hydraulic metering device
AssigneeOil-Rite Corporation
InventorsDonald G. Gruett, Michael J. Wech
Life of this patent
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Abstract
The metering device for a liquid medium comprises a cylinder and a piston operatively disposed therein to define a metering chamber ahead of the piston. The outlet end of the cylinder is open and closed by an evacuation valve. The piston is driven forwardly through a working stroke to force the liquid medium in the metering chamber out of the chamber and past the evacuation valve. A check valve located in the metering chamber moves from a closed to an open position on each working stroke to preclude entrapment of air in the metering chamber and thus provide for more accurate metering. The metering device may include means to regulate the length of the working stroke.
Claims6
A metering device for a liquid medium under pressure, the metering device comprising:
- a housing having an inlet and an outlet for said liquid medium, said housing including a first chamber having an open end communicating with said outlet;
- a first check valve means in said housing, said first check valve normally biased to close said open end of said first chamber;
- a first piston having a drive end, said first piston slidably received and operatively disposed in said first chamber, said first piston and said first chamber defining a metering chamber;
- means to conduct said liquid medium from said housing inlet to said metering chamber;
- a second check valve located in said housing, received and operatively disposed in said first piston drive end and moveable between and including at least a first position and a second position, whereby pressure from said liquid medium moves said second check valve;
- and
- said first piston forcing said liquid past said first check valve means to completely evacuate said metering chamber on each working stroke to thereby generally preclude entrapment of air in said metering chamber.
Dependencies are inferred from the claim text.