Refrigeration – Cooled enclosure – Ice support – e.g. – container
Reexamination Certificate
2000-02-04
2001-05-15
Doerrler, William (Department: 3744)
Refrigeration
Cooled enclosure
Ice support, e.g., container
C062S049200, C062S050100
Reexamination Certificate
active
06230516
ABSTRACT:
BACKGROUND OF THE INFORMATION
1. Field of the Invention
The present invention generally relates to a container holding a liquid and, more particularly, to a mixing container holding at least two liquid constituents in intended proportions. In a preferred form of the present invention, the liquid held in the mixing container is a breathable, cryogenic liquid.
To provide the breathable, cryogenic liquid, a first liquid constituent, predominantly comprising either oxygen or nitrogen, is loaded into the mixing container until it occupies that percentage of the total interior volume intended to hold liquid corresponding approximately to the first liquid constituents known percentage of air. Then, a second, cryogenic liquid constituent, predominantly comprising the other of oxygen or nitrogen, is loaded into the mixing container to completely fill the interior container volume intended to hold liquid. The percentage of the interior volume occupied by the second liquid constituent corresponds approximately to the known percentage of air of the second liquid constituent. The percentages can be adjusted to make the mixture richer in oxygen to insure that the mixture is at least twenty-one percent oxygen and to account for variations in the concentration of the oxygen related to time and other factors.
2. Prior Art
It is known that space requirements and container weight can be substantially reduced for gas storage and delivery systems involving relatively large volumes by maintaining the gas in the more dense liquid phase rather than as a gas or a supercritical fluid. When the liquefied gas is intended to be a breathable gas or in any system intended to contain multi-constituent gases of different boiling points, the conventional practice is to mix the various liquid constituents and store the mixture in a main storage tank. However, when multi-constituent liquefied gases are stored in insulated containers over relatively extended time periods, inevitable heat input to the stored liquid tends to cause evaporation. With multi-constituent liquefied gases of different boiling temperatures, this evaporation will change the relative composition of the stored liquid. Specifically, liquid constituents having lower boiling points will tend to evaporate preferentially resulting in vapor in the container being relatively richer in those constituents with the remaining liquid being leaner in constituents having lower boiling points.
The mixing container of the present invention is an improvement in filling and storing a multi-constituent liquid in that it enables the liquid, for example, a liquefied breathable gas mixture such as liquid air predominantly comprising oxygen and nitrogen to be mixed only at such time as it is anticipated that the breathable gas will be used in the near future. During periods of extended storage, the oxygen and nitrogen liquid constituents can be separately held in dedicated bulk storage containers. That way, the inevitable heat transfer to each of the stored liquid constituents will not result in any change in the composition of the liquid or its gaseous head. Then, at such time as it is anticipated that a liquefied, breathable gas mixture will be needed, the oxygen and nitrogen liquid constituents are filled into the mixing container of the present invention.
The thusly prepared liquid mixture can then be dispensed from the mixing container and gasified for use or, the mixing container can be used to fill the liquid mixture or its gaseous state into other cylinders such as the kind typically used in self-contained breathing apparatus (SCBA) and the like. If the interim period between filling and use is not too prolonged, the liquid and/or gaseous mixture will comprise its constituents within acceptable intended percentages. Also, the present mixing container is constructed such that filling the liquid constituents therein automatically results in a liquid mixture comprising each of the constituents in their intended respective percentages.
SUMMARY OF THE INVENTION
The present invention is thus directed to a mixing container for providing a multi-constituent liquid, preferably a cryogenic liquid air mixture filled in the container. The mixing container has at least two vent conduits communicating between respective fill positions or levels inside the container and the outside thereof. A first liquid, which is preferably nitrogen, is filled into the mixing container through a fill conduit until the first liquid contacts the first vent conduit disposed at a first level inside the container. The nitrogen then communicates through the first vent conduit and blows off through a vent valve. This valve is closed and liquid oxygen is then introduced into the mixing container through the fill conduit until the quantity of the liquid oxygen and liquid nitrogen mixture in the container contacts the second vent conduit disposed at a second level inside the container, spaced from the first level. The combined liquid oxygen and nitrogen mixture then communicates through the second vent conduit and blows off through a second vent valve. The second vent valve and a valve for the fill conduit are closed to complete the filling procedure.
The sequence for introducing the two liquids can be reversed. In that case, liquid oxygen having a boiling point of about −300° F. is first loaded into the cryogenic mixing container followed by the liquid nitrogen having a boiling point of about −320° F. Thus, the liquid nitrogen will boil relatively little of the liquid oxygen off of the mixture. However, liquid nitrogen is non-flammable and when it is loaded first, it acts as a diluent for the liquid oxygen to thereby lessen the probability of a fire.
By addition of a mechanical refrigerator, the mixing tank of the present invention can be made into a zero loss liquid-air container that can be stored for extended periods of time without changing the percentage of oxygen in the mixture.
The foregoing and additional advantages are characterizing features of the present invention that will become clearly apparent upon a reading of the ensuing detailed description together with the included drawings wherein:
REFERENCES:
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patent: 2645907 (1953-07-01), Droste et al.
patent: 3371497 (1968-03-01), Singleton
patent: 3717006 (1973-02-01), Kimmel et al.
patent: 3830073 (1974-08-01), Cappiello
patent: 3838576 (1974-10-01), Geffs
patent: 4918927 (1990-04-01), Eigenbrod
patent: 5357758 (1994-10-01), Andonian
patent: 5819544 (1998-10-01), Andonian
Andonian Family Nominee Trust
Doerrler William
Hodgson & Russ LLP
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