Positive displacement dispenser and method for dispensing discrete amounts of liquid
AssigneeNordson Corporation
InventorsDavid J. Dunlap, Laurence B. Saidman, Edward C. Taylor
Life of this patent
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Abstract
A dispenser for applying small amounts of liquid to a substrate. The dispenser includes a dispenser body, an actuator in the dispenser body, and a dispensing element including a dispensing element body removably coupled to the dispenser body. A valve stem is mounted for reciprocating movement within the dispensing element body. Additional aspects include a deformable valve seat, a deformable and resilient valve stem tip and a method of applying liquid in discrete amounts to a substrate.
Claims8
A dispenser for applying small amounts of liquid to a substrate, the dispenser comprising:
- a dispenser body;
- a valve stem mounted for reciprocating movement within said dispenser body, said dispenser body further including a liquid chamber and said valve stem including a tip mounted for reciprocating movement within said liquid chamber between open and closed positions;
- and
- a valve seat in said dispenser body engaging said valve stem tip in the closed position;
- wherein said valve stem tip is formed from a deformable, resilient material, said valve stem tip being deformed against said valve seat when said valve stem moves to the closed position thereby damping impact of the valve stem tip against said valve seat and forming an area of sealing contact between said valve stem tip and said valve seat.
A method of applying a small amount of liquid to a substrate during a dispense cycle, the liquid being dispensed from a dispenser including a valve stem with a tip, a liquid chamber, a liquid dispensing passage communicating with a liquid dispensing outlet, and a valve seat positioned between the liquid chamber and the liquid dispensing passage, the method comprising:
- (a) moving the valve stem tip from a closed position which is engaged with the valve seat to an open position which is disengaged and spaced from the valve seat;
- (b) allowing pressurized liquid to flow from the liquid chamber past the valve stem tip and into the liquid dispensing passage;
- (c) moving the valve stem tip from the open position to the closed position while dispensing the small amount of liquid onto the substrate;
- maintaining the valve stem tip in the closed position while moving the substrate and the dispenser relative to each other to place the dispenser at a new dispensing location;
- and
- initiating a subsequent dispense cycle at the new location by repeating steps (a)-(c).
Dependencies are inferred from the claim text.