US2279705A - Liquefied gas odorizer and method of using same - Google Patents

Description

April 14, 1942. w. c. DAYHUFF ,2 9, 05

I LIQUEFIED GAS ODORIZER A ND METHOD OF USING SAME Filed Aug. 8, 1938 Fly! Fig.2

INVENTOR ATTORNEY Patented Apr. 14, 1942 UNITED STATES PATENT OFFICE I LIQUEF'IED GAS fit z nn AND METHOD Walter C. Dayhufl, Whittier, Calif., assignor to Standard Oil Company oi. California, San Francisco, Calif., a corporation of Delaware Application August 8, 1938, Serial No. 223,708

(Cl. 62-1) l the liquefied gas and so is independent of such prior art practice.

This invention comprehends broadly a-method and means for withdrawing gas from a cylinder or tank ofodorized liquefiedfuel gas including 7 Claims.

This invention relates to the odorization of liquefied fuel gas, such as butane, propane and the like, and particularly refers to a method and means for releasing gas from the conventional container or portable cylindrical tank in which the liquefied gas is maintained under suitable pressure in such a manner that the concentration of odorant in the gas discharged from the container will remain substantially constant during the entire emptying procedure. 10

Odorization of liquefied gas fuel is considered necessary to provide protection against fire hazards and explosions which may result from gas leaks.- The usual method of efi'ecting odorization is to add the required amount of liquid odorizing material, for example; that described in United States Patent No."2,094,270 issued September 28, 1937 to W. H. Hampton et all, directly to the liquefied gas' stock. -When this stock isv converted into vapor by so-called cross-cut vaporization of the liquid, as by withdrawing liquid per se from its tank or container and then evaporating it in a preheater or vaporizer, the

concentration of. odorant in the liquid remains constant, and is identicah with the concentrausually less volatile than the liquefied gasesto which they are added, and as a result the first gas removed in differential vaporization carries less odorant with it than does the gas removed Y as the liquefied fuel charge in the cylinder ap-' proachesdepletion. Furthermore, if the temperature of the tank or cylinder containing the liquefied gas becomes lower, as by cooling from evaporation or from other causes, the tendency tendency by, modifying the nature of the odorant or by adding'retaining liquids, as in United States Patent No; 1,944,175 issued January 23, 1934. This invention, however, is entirely concerned with the method and means associated with rethe step of passing said vaporized gas over an extended solid surface which is continuously wet with the liquefied material and then releasing the gas for any desired use.

It is an object of this invention to provide a method and apparatus for withdrawing odorized gas from a tank or cylinder containing a quantity ofodorized liquefied gas with a smaller variation in odorant intensity. in the gas than 'has heretofore been possible.

Another object is to provide a simple means that will function automatically and without at- I tention to produce the desired result, and which.

may beinstalled in each cylinder or tank of liquefied fuel gas with slight expense and modification of the'existing structure. I Another object is to provide a method of odorizing liquefied gas that will give a more uniformly odorized product, thereby permitting a smaller quantity of relatively expensive odorant to be used to produce; a given odorant intensity in the gas.

Another objects is to provide an odorizerthat will functioneven when the tank or cylinder is 0 not actually connected to a gas distributing system, to indicate a leak in the tank or in the shutoff valve thereon.

These and other objects and advantages will be apparent from the following description and from the accompanying drawing, which forms a part of this specification and illustrates a preferred embodiment of the invention as applied to a conventional cylinder of liquefied fuel gas.

In the drawing, Figure 1 is-a vertical and part 0 sectional view of a liquefied gas cylinder with its,

discharge connection modified to practice this invention.

V Figure 2 is a longitudinal sectional view, to a for the odordnt to remain in the tank becomes] somewhat larger'spale' of discharge connection more marked as the liquefied gas evaporates and and wick suitable to practice the invention.

The usual construction of a tank or cylinder for liquefied'gas, such as propane, butane and the like, includes a tank shell l0, usually of drawn steel, to which is secured a cap or closure l 1, threaded as at l2 to receive a similarly threaded valve member l3. @Valve l3 isfitted at one side with a-threaded: outlet it and a suitable valve stem l5, by means of which the release of gas from the tank may bec'ontrolled.

' moval of gas from the cylinder or container for r In order to' provide an extended solid wette surface over which the vapor or-gas must pass in leaving tank II, the inlet to valve I3 is threaded as at It to receive a nipple i1 and pipe II, the latter extending substantially to the bottom of tank shell, is. Pipe is is perforated at intervals 5 as at II, and is preferably so arranged that all the gas or vapor leaving tank ll must pass along -a substantial portion of its length. Preferably the perforations II are closer together at the upper end of pipe II, as shown.

The extended solid wetted surface may be 'of any suitable material, but in the example shown isa wick of soft cotton or other capillary ma- 7 terialjl, extending throughout pipe I8 and preferably provided with some means for retaining it in place, such as pin 2l.- Liquefied fuel was cylinders of this type are invariably placed in the upright position shown when they are con-- nected for use, so that-the wick II will always be wet for at least a portion of its length so long as any odorised liquefied gas remains in tank ll.

The'explanation for the operation of this invention is not. definitely understood, but its usefulness has been demonstrated by numerous successful tests, and appears to involve only the step of intimately contacting the outgoing gas or vaporwith an extended solid wetted by the odorised liquid. Obviously other means than that shown could be utilized'for carrying out this procedure: With variations in temperature between 32' F. and 90 1". and for full andhalf empty cylinders the variation in odor intensity of the withdrawn gas or vapor was found to be negligible. Also, the odor intensity of gas withdrawn from cylinders using this method was at least twice as great as that withdrawn from cylinders of the same material and containing the 1 same kind and amount of odorant but where the outgoing gas was not contacted with the ex tended solid wetted surface.

Although but a single application of the -methcd and asingle specific example ofmeans passing to the outlet-of said ontalner.

for practicing this invention are described above,

. itis obvious that numerous modifications and changes could be made without departing from their essential features, and'all such that come within the scope-of the appended claims are embraced thereby. 4

I claim: v .1

1. In themethod-of odorislng liquefied -fuel gas such as butane, propane and the like, to which a volatile odorant material has been added in the liquidphase. and which-is maintained in.

liquid phase by being stored under pressure. the steps of releasing. the pressure onsaid liquefied I gas so that it will evaporate and contacting said vapor with an extended solid surface wetted by said liquefied gas.

2. The method of odorizing a liquefied hydrocarbon or a mixture of hydrocarbons, such as butane, propane, and the like, comprising the steps of adding an odorant material to said liquefied hydrocarbon, maintaining said odogized hydrocarbon in a container under a pressure adequate to maintain a liquid phase and a vapor phase hydrocarbon from said container by releasing the pressure thereon, and, prior to its withdrawal, contacting said vapor phase hydrocarbon with an extended solid surface in said container wetted with the liquid phase of said hydrocarbon.

3. In combination with a pressure container for odorized liquefied gas, only a single valved outlet means for releasing gas from said container and means in said container adapted to .provide an extended surface wettedby the liquefied gas in said container and in communication with said outlet. so constructed and arranged that gas released from said container will-first said last named means extends substantially throughout the height of said container so as to contact said extended surface. 4. A. combination as defined in-claim 3 in which tainer, and means in said conduit forming an extended surface adapted to be wetted by the liquid in said container and to be contacted by the gas 6. An 'odorizer for liquefied gas contalners as defined in claim 5 in which last named means comprises a capillary material.

7. An attachment foran odorized liquefied gas container comprising a tube adapted to extend inwardly from the outlet of said container to a point near the bottom thereof, a plurality of openings in the wall of said tube, so that gas released from said liquid in said container may enter said tube'regardless of the level of the liquid in said container and a wick'of capillary material extending substantially throughout the length or said tube. 1

' v C. DAYHUFF.

phase in said containenvwithdrawing only vapor

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