Dispensing – Nozzles – spouts and pouring devices – Antidrip
Reexamination Certificate
2001-05-10
2004-03-02
Mancene, Gene (Department: 3754)
Dispensing
Nozzles, spouts and pouring devices
Antidrip
C222S383100, C222S108000, C239S119000
Reexamination Certificate
active
06698629
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to fluid dispensers, and more particularly to comestible fluid dispensing taps and methods of dispensing comestible fluid from such taps.
BACKGROUND OF THE INVENTION
A large number of comestible fluid dispensing systems and taps exist, most of which are adapted to dispense a particular type of comestible fluid. For example, some systems and taps are well-suited for dispensing relatively low-viscosity comestible fluids such as beer, soda, and other beverages, while other systems and taps are designed for dispensing more viscous comestible fluids such as ketchup, mustard, relish, mayonnaise, and other condiments. These latter comestible fluids often present unique problems for condiment dispensing systems and taps due to their higher viscosity. For example, relatively viscous condiments hang from a tap after dispense. This not only presents an unappealing appearance to later users of the tap, but also increases the chance that the dangling condiment will spoil before being used. Either result can significantly lower the desirability of the condiment and can therefore negatively impact condiment sales. Although the chances for hanging condiment is greater with higher viscosity fluids, the problems just described are relevant for virtually every comestible fluid (and are addressed by the present invention as described below).
Conventional comestible fluid dispensing systems and taps also address comestible fluid drip problems in varying ways and with varying success. Comestible fluid dripping between dispenses is undesirable for obvious reasons, and can be dependent upon the type of comestible fluid being dispensed.
A number of conventional devices and methods exist for addressing dangling comestible fluid and dripping problems described above. For example, the condiment dispensing system disclosed in U.S. Pat. No. 5,624,056 issued to Martindale employs a movable valve element which swipes the nozzle of the tap to remove excess condiment therefrom. In U.S. Pat. Nos. 6,082,587 and 5,906,266 issued to Martindale et al., a valve is used to reverse condiment flow at the end of condiment dispense to pull condiment on the nozzle back into the nozzle.
Conventional devices and method used for preventing comestible fluid buildup, dangling, and drips on a tap nozzle have a number of significant limitations. Typically, such devices and methods only partially protect against comestible fluid spoilage because comestible fluid that has exited the tap or nozzle is often still partially or fully exposed to the outside environment (although not always visible to a user). Also, such devices and methods employ relatively complex mechanisms for performing their tasks to prevent comestible fluid buildup, dangling, and drips. These mechanisms can therefore can be expensive to manufacture, assemble, and maintain, thereby adding to dispensing system and tap cost.
As mentioned above, some conventional devices and systems employ a drawback valve to draw comestible fluid back into the tap or nozzle after a dispense. A problem with such devices and systems is that the draw-back valve adds yet another component to the comestible fluid dispenser, requiring additional comestible fluid lines and connections, significantly adding to the total cost of the dispenser, and increasing system complexity. Furthermore, the draw-back valve in these dispensers is a separate device located a distance from the tap and connected to the tap often by two or more fluid lines. Therefore, the ability to control the draw-back force and the amount of comestible fluid drawn back by the valve is limited.
The required draw-back force and the resulting amount of drawn comestible fluid can vary greatly from fluid to fluid (often dependent at least in part upon comestible fluid viscosity and other comestible fluid properties). Lack of draw-back control can present problems when the same dispensing system and draw-back valve is employed to dispense different types of comestible fluids. Problems include drawing in air with the comestible fluid using too much drawing force from the draw-back valve and not providing sufficient force to draw comestible fluid back into the tap or nozzle.
In light of the problems and limitations of the prior art described above, a need exists for a comestible fluid dispensing apparatus, tap, and method which is well-suited for dispensing different types of comestible fluids, reduces or preferably eliminates comestible fluid buildup and dangling comestible fluid from nozzles and taps, prevents dripping, reduces exposure of comestible fluid to the environment between dispenses, is relatively simple in construction, assembly, and maintenance, is inexpensive and adds little to no cost to a conventional comestible fluid dispensing system or tap, and permits increased control over comestible fluid draw-back. Each preferred embodiment of the present invention achieves one or more of these results.
SUMMARY OF THE INVENTION
In one preferred embodiment of the present invention, the dispensing apparatus includes a pump operable to pump comestible fluid from a comestible fluid source to a tap provided with a draw-back valve. In some embodiments, the pump can be manually operated or can be powered by a motor or other conventional driving device, while other embodiments do not employ a pump but instead control the flow of comestible fluid under pressure to the tap. In the latter embodiments, flow to the tap can be controlled by an upstream valve.
The tap of the present invention is preferably provided with a draw-back valve capable of drawing comestible fluid in an upstream direction in the tap. Preferably, suction generated by closure of the draw-back valve is employed for one or more purposes including: to remove any comestible fluid dangling from the tap, to draw comestible fluid into the tap away from view and from exposure to the environment, to reduce comestible fluid buildup on and near the tap outlet, to enclose or at least partially enclose comestible fluid downstream of the draw-back valve, and to operate a downstream cutoff valve in the tap.
The draw-back valve is preferably a plunger valve, although other types of valves known in the art can generate sufficient suction force to perform the functions just described. The draw-back valve is movable between opened and closed positions, and more preferably is movable between at least one open position and a range of closed positions. As used herein and in the appended claims the term “valve” refers to that element or mechanism that is movable to enable and stop fluid flow out of the tap in different positions of the valve. For example, the draw-back valve in some preferred embodiments is a plunger valve as mentioned above. In such cases, the plunger valve refers to the plunger itself, and not to the passage through which the plunger moves or the seat (if any) against which the plunger stops when fully closed.
Some highly preferred embodiments employ a draw-back valve that moves through a passage having a substantially constant cross sectional area, a cross sectional area that increases in the downstream direction, or a passage having a portion with a substantially constant cross sectional area and a portion having an increasing cross sectional area in the downstream direction. The draw-back valve need not move fully through the passage (or passage portions), but moves sufficiently to produce the suction force described above. The size of the passage with respect to the draw-back valve, the shape of the passage and passage portions, the distance the draw-back valve moves in the passage (or passage portions), and the speed at which the draw-back valve moves are preferably selected to provide the desired suction force.
In one highly preferred embodiment, the closing draw-back valve moves first at least partially through a passage portion having a passage portion having an increasing cross sectional area in the downstream direction and then through a passage portion having a substantially constant cross sectional area.
Mancene Gene
Michael & Best & Friedrich LLP
Nicolas Frederick C.
SHURflo Pump Manufacturing Co., Inc.
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