Pumps – Expansible chamber type – Valved piston
Reexamination Certificate
1999-12-10
2001-04-24
Walberg, Teresa (Department: 3742)
Pumps
Expansible chamber type
Valved piston
Reexamination Certificate
active
06220835
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to dispensing systems, and more particularly to a pump for dispensing condiments and the like.
It is often desirable to dispense a condiment or the like by consistent amounts. Both mechanical and electronic devices have been used to control the portion dispensed with varying degrees of success. Some of the devices are rather complex and expensive. Others may be unsuitable for dispensing condiments that contain solids or semi-solids.
SUMMARY OF THE INVENTION
The present invention relates to a pump for dispensing condiments or the like. The pump provides a simple and reliable mechanism for providing consistent portion control in dispensing, and is especially suitable for dispensing condiments that contain solids or semi-solids or particles such as in thousand island dressing and various “secret sauces” favored by restaurants.
The invention provides a reciprocating piston in a chamber. The piston has a transfer check valve which permits condiment flow only in a direction from an inlet side of the chamber to an outlet side of the chamber. The outlet side of the chamber includes an outlet with an outlet check valve. When the piston is moved from the outlet side to the inlet side of the chamber, the transfer check valve is open to permit condiment flow from the inlet side to the outlet side of the chamber, and the outlet check valve is closed to accumulate condiment therein. Upon accumulation of a desired amount of condiment in the outlet side of the chamber, the piston is moved from the inlet side to the outlet side of the chamber. During that time, the transfer check valve is closed and the outlet check valve is open to dispense the accumulated condiment in the outlet side of the chamber. At the same time, condiment is flowed into the inlet side of the chamber. The amount of condiment transferred to the outlet side of the chamber is determined by the piston stroke, and can be controlled to produce a consistent amount for each cycle of accumulating and dispensing condiment. The cycle is repeated to provide dispensing action with simple portion control. The outlet check valve and transfer check valve may be elastomeric check valves as described in U.S. patent application Ser. No. 09/422,826.
In accordance with an aspect of the present invention, a condiment dispensing pump comprises a pump chamber including a cavity having an inlet chamber cavity portion and an outlet chamber cavity portion. The pump chamber has an inlet fluidicly coupled with the inlet chamber cavity portion and an outlet fluidicly coupled with the outlet chamber cavity portion. An outlet check valve is disposed at or near the outlet of the pump chamber, and is openable to permit flow only in a direction from the outlet chamber cavity portion out through the outlet check valve. A piston is disposed in the pump chamber cavity between the inlet chamber cavity portion and the outlet chamber cavity portion. The piston is movable in the pump chamber cavity to reapportion the volume of the pump chamber cavity between the inlet chamber cavity portion and the outlet chamber cavity portion. The piston includes a piston check valve which is openable to permit flow only in a direction from the inlet chamber cavity portion through the piston check valve to the outlet chamber cavity portion.
In some embodiments, the piston is movable between a first position when the inlet chamber cavity portion has a minimum volume and the outlet chamber cavity portion has a maximum volume, and a second position when the inlet chamber cavity portion has a maximum volume and the outlet chamber cavity portion has a minimum volume. The piston check valve is closed and the outlet check valve is open when the piston moves from the first position to the second position to draw a flow from the inlet into the inlet chamber cavity portion and to produce a flow from the outlet chamber cavity portion out through the outlet. The piston check valve is open and the outlet check valve is closed when the piston moves from the second position to the first position to permit flow from the inlet chamber cavity portion to the outlet chamber cavity portion and to prevent backflow through the outlet into the outlet chamber cavity portion.
In specific embodiments, the piston is movable in the pump chamber cavity in a generally linear manner. The piston has a generally constant stroke. An air cylinder is coupled with the piston to move the piston in the pump chamber cavity.
In accordance with another aspect of the invention, a portion control dispensing apparatus comprises a chamber including a cavity having an inlet and an outlet. An outlet check valve is disposed at or near the outlet of the chamber, and is openable to permit flow only in a direction from the chamber cavity out through the outlet check valve. A transfer check valve is disposed in the chamber cavity. The transfer check valve is movable in the chamber cavity between a first position near the inlet and away from the outlet and a second position near the outlet and away from the inlet. The transfer check valve is closed when moved from the first position to the second position and is open when moved from the second position to the first position.
In accordance with another aspect of the invention, a condiment dispensing pump comprises a pump chamber including a cavity having an upstream chamber cavity portion and a downstream chamber cavity portion. The pump chamber has an inlet fluidicly coupled with the upstream chamber cavity portion and an outlet fluidicly coupled with the downstream chamber cavity portion. An outlet valve is disposed at or near the outlet of the pump chamber. A transfer valve is disposed in the pump chamber cavity. The pump includes a mechanism for increasing the volume of the downstream chamber cavity portion and decreasing the volume of the upstream chamber cavity portion when the transfer valve is open and the outlet transfer valve is closed to transfer fluid accumulated in the upstream chamber cavity portion into the downstream chamber cavity portion, and for decreasing the volume of the downstream chamber cavity portion and increasing the volume of the upstream chamber cavity portion when the transfer valve is closed and the outlet valve is open to transfer the fluid in the downstream chamber cavity portion out through the open outlet valve and to draw fluid through the inlet for accumulation in the upstream chamber cavity portion.
In some embodiments, the outlet valve comprises an outlet check valve which is openable to permit flow only in a direction from the downstream chamber cavity portion out through the outlet check valve. The transfer valve comprises an transfer check valve which is openable to permit flow only in a direction from the upstream chamber cavity portion to the downstream chamber cavity portion. In specific embodiments, the outlet check valve and transfer check valve may be elastomeric check valves.
Another aspect of the invention is directed to a method of providing portion control pumping, which comprises providing a transfer valve in a chamber between an inlet disposed at an inlet side of the chamber and an outlet disposed at an outlet side of the chamber. An outlet valve is provided at the outlet. The transfer valve is moved from the inlet side of the chamber to the outlet side of the chamber with the transfer valve closed and the outlet valve open to draw fluid through the inlet into the inlet side of the chamber and dispense fluid from the outlet side of the chamber out through the outlet. The transfer valve is moved from the outlet side of the chamber to the inlet side of the chamber with the transfer valve open and the outlet valve closed to transfer fluid from the inlet side of the chamber through the transfer valve to the outlet side of the chamber.
REFERENCES:
patent: 2621889 (1952-12-01), Annin
patent: 4869404 (1989-09-01), Elliott
patent: 5380175 (1995-01-01), Amarume
patent: 5381932 (1995-01-01), Humphrey
patent: 5435466 (1995-07-01), Du
patent: 5667105 (1997-09-01), Hartley et a
Bennett Charles E.
Jepson Antonio J.
Salmela Juha K.
Automatic Bar Controls Inc.
Patel Vinod D.
Townsend and Townsend / and Crew LLP
Walberg Teresa
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