Fluid handling – Diverse fluid containing pressure systems – Foam control in gas charged liquids
Reexamination Certificate
1999-09-01
2001-04-03
Michalsky, Gerald A. (Department: 3753)
Fluid handling
Diverse fluid containing pressure systems
Foam control in gas charged liquids
C137S173000, C137S192000
Reexamination Certificate
active
06209567
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
This invention relates to devices for preventing the foam and froth that surges out of a gas propelled liquid container, or from a system using a mechanical pump, when the liquid supply is depleted, from passing into the distribution lines of the dispensing system to which it is attached. This invention relates more particularly to a foam trap, or FOB as it may be called, for keeping the froth from a near-empty beer keg or the like from entering the dispensing lines that carry the beverage to the tap.
2. Background Art
Beer and other carbonated beverages, when poured carefully into a glass or mug for an individual serving, generate a natural head of foam that, when not excessive, tends to enhance the presentation and taste of the beverage for the consumer. In a commercial setting such as a restaurant or tavern, the beer is dispensed from a “remote” beer dispensing system.
To transport the beer from the cooler to the point of dispensing, the beer travels through a beer conduit, an insulated bundle of beer lines and coolant lines. The beer is typically propelled by gas pressure applied over the beer in the keg. The keg is said to “kick” as it empties, when the level of the liquid beer falls below the discharge outlet in the keg. When this occurs, a frothy mixture of propellant gas and residual beer are blown out through the beer lines or hoses. When this happens, it causes at best an erratic, unsatisfactory, gassy pour of the residue that is difficult or impossible to control at the tap. To resume satisfactory dispensing of liquid beer, the lines must be repacked, refilled with beer and the gas displaced.
Various designs of foam traps or FOBs as they may be called, are presently in commercial use to prevent the entrance of excessive foam into the distribution lines as the keg hits empty, with shutoff valves that hold the liquid in the lines while the empty keg is being replaced or the system is being switched to an already connected next keg. The prior art of Francisco Moreno Barbosa, as expressed in UK Patent GB2286581 is instructive, as are the examples of commercial products accompanying this application. Most devices use a float to seal the outlet of a reservoir to which the beer lines are attached when the level of liquid in the reservoir falls low. There is an alternate device that operates on a fluid momentum theory, gas versus liquid. All have inherent problems with cost, operation, sanitation, reliability or maintenance.
There are many commercial and industrial processes that use gas-propelled liquid pumping or dispensing systems, where it is likewise desirable to prevent or control the amount of foam entering the distribution lines. Liquid dispensing systems using vented containers and mechanical pumps are also subject to the same problem, when the liquid level in a vented tank or container falls to level of the outflow port or suction tube so that air is being sucked into the pump along with the residual liquid.
SUMMARY OF THE INVENTION
It is among the objects of the invention to keep the distribution lines that transport the beer or other liquid in a mechanically pumped or gas propelled liquid dispensing system, full of liquid at all times, and free of propellant gas, air, or foam, by utilizing a novel foam trap or FOB connectable to a liquid container or a manifold to which are connected multiple containers.
It is further among the objects of the invention to employ the trap in an automated control system on a liquid dispensing system pre-connected by a manifold to multiple containers, to sequence the containers when empty without introducing gas or air into the dispensing system.
The FOB has a reservoir or chamber into which the liquid is piped. The chamber is of suitable interior volume with respect to the viscosity and flow rate of the liquid to act as a coarse gravity separator of the liquid and gas when gas enters the supply line from the container. The chamber has two outlets, an upper gas vent outlet for discharge, and a lower liquid outlet to which the distribution lines are attached. Each outlet is configured with a horizontally oriented valve seat suitable to accept a vertically displaced spherical closing member or floating ball stopper in a sealing relationship. Within the chamber there is a free floating ball stopper for each valve seat, suitable for sealing its respective valve seat when moved and held against it by pressure or gravity. The FOB also has externally accessible mechanisms for restraining the seating of or for unseating either of the balls independently, when desired. The geometry of the chamber, valves and balls is such that the balls do not compete for either valve seat when both are afloat in rising or falling liquid.
To initiate use, the liquid outlet ball sealing restraint is put in place to insure that the outlet port ball stopper is loose, and the gas vent outlet ball seating restraint is disengaged or removed to allow automatic closure. When liquid enters the chamber from the liquid containers, both ball stoppers are raised with the rising liquid level, and the gas vent ball is floated into place on the vent valve seat, closing the vent port. The ball stopper is held in place by the pressure of the liquid and gas in the system. When maximum pressure is reached, the liquid outlet ball sealing restraint is removed to permit automatic closure, but the liquid outlet ball stopper is still being floated by the liquid in the chamber so the liquid outlet remains open to pass liquid through the lines to the dispensing point until the liquid level drops.
When the container in use is exhausted and “kicks”, and the liquid in the trap chamber goes low as it is replaced by propellant gas or air in the system, the liquid outlet is closed and sealed by its ball stopper so that gas or air does not enter the distribution lines. Meanwhile, the gas vent ball stopper remains in place under pressure, maintained by a check valve at the container end of the liquid supply line. Sensing the low pressure in the dispensing line, the operator or the system controller changes or switches to a full container and the supply of liquid is re-established. Thereupon, the gas vent ball stopper is the unseated to open the vent port, and the restraint then removed. This permits the flow of liquid into the chamber to empty the gas and reseat the vent ball. When the vent has closed and the chamber has stabilized at maximum pressure, the liquid outlet ball stopper is unseated and the restraint then removed to resume normal operation.
It is further among the objects of the invention to provide a FOB that is constructed of materials suitable for contact with food, rugged and reliable, simple to use. hygienic in that it has minimal crevices in the food zone, is easy to disassemble, clean and maintain, and is suitable for regulatory approval. It is yet further among the objects of the invention to utilize principles of symmetry of design and commonality of parts for similar functions to minimize the number of unique parts.
It will be apparent to those skilled in the art, that the invention functions with carbonated or gaseous liquids or fluids, with mixtures of gas and liquid, and with liquids or fluids that are either gas-propelled or mechanically pumped from a container into which replacement air or gas or gaseous fluid flows.
Still other objects and advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein we have shown and described only a preferred embodiment of the invention, simply by way of illustration of the best mode contemplated by us in carrying out our invention.
REFERENCES:
patent: 5564459 (1996-10-01), Dunne
patent: 6082389 (2000-07-01), Latham et al.
patent: 2286581A (1995-08-01), None
Metallocraft FOB Detector FB01, Metallocraft & Engineering Ltd, Dublin, Ireland (Updated).
Banner Profit Guard PG-1, Franklin Park, Illinois (Updated).
1999 Foxx Equipment Company Catalog 20D03-429, Foam Preventer 07D08-101.
Ajax
Asmus Scott J.
Maine Vernon C.
Michalsky Gerald A.
Vernon C. Maine PLLC
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