US2416924A - Method and means for producing ebullition in liquefied petroleum gases - Google Patents

Description

N. M, JONES .l .Tw e e h q v S t e e h W S T; s mi. T;- m Um BS EA GGSA mMw CUl um my. Pm RP@ ODe FEF I MFM AE1 EUi Q MIF ML Am D O H T E M March 4, .194?.

N. M. JONES 2,416,924 METHOD AND MEANS FOR PRODUCING EBULLITION IN LIQUEFIED PETROLEUM GASES Filed Feb. 27, 1943 3 Sheets-Sheet 2 Zhwentor: Fie/ son Nl. Joh/Es '(1 ttorneg 5 Patented Mar. 4, 41947 METHOD AND MEANS FOR PBODUCIN G EBULLITION IN LIQUEFIED PETROLEUM casas Nelson M. `Jones, Sarasota, Fla., assignor to Greens Fuel, Incorporated, Sarasota, Fla., a corporation of Florida i Application February 27, 1943, Serial No. 477,373

This invention relates to a method and means for producing ebullition and more particularly to the ebullition of liqueed petroleum gases such as .butane, propane, and the like.

Butane mixtures, such as used for domestic `fuels, have a theoretical initial boiling or evaporating point which is around eighteen degrees Fahrenheit. At this temperature, the boiling barely starts. In practice, when the temperature of butane falls to approximately thirty-two to thirty-live degrees Fahrenheit, such boiling. or evaporation ceases because the liquid is still. It, however, 'the liquid is properly agitated by mechanical or other means, the boiling will take place at a lower temperature, theoretically down to eighteen degrees Fahrenheit.

Liqueied petroleum gases are widely used in some sections for domestic purposes. It is a common practice to pipe ,liquefied butane, propane, and the like from a delivery tank into a closed underground tank so that the heat of the earth will cause the liquid to boil and form a gas or vapor, which vapor is piped to points of consumption. 'Since liquid butane, in practice, does not actually boil until a temperature of around thirty-two to thirty-five degrees Fahrenheit is reached, operation in cold weather is sometimes troublesome. Even though the tanks are buried beneath the top of the ground, the temperature of the liquid sometimes falls below vthe actual boiling point, and as a resultI no 3 Claims. (Cl. 62-4) permanently changed and therefore such materials are commonly called ebullators.

It is another object of this invention to provide a catalytic agent of a capillary structure such as rattan, reed, bamboo, or cellular woods with the natura1 skin thereon, in combination with a supply of liqueed petroleum gas, which agent is capable of producing an internal pressure diierential underneath the surface of the liquid and thus produce bubbles of gas for asitating the main body of the liquid. The use of rattan, reed. bamboo, and other cellular woods in. this invention is most effective when employed in the natural form; that is, permitting the natural skin to remain thereon and being cut in suitable lengths between the joints so that the longitudinal capillary passages will extend from end to end of the lengths. The

' natural skin is necessary to this process because g5 ground tank for containing vaporizable liquid petroleum gases such as butane, propane, and the like, or mixtures thereof inf combination with tubular pipes or recesses communicating with the lower portion of the tank for housing catalytic agents such as rattan, reed, bamboo, or other cellular woods. The pipes or recesses are heated by the surrounding earth to cause the liquefied petroleum gas and catalytic agents within the pipes or recesses to also be heated, thereby causing ebullition to be controlled more directly by the ground temperature than is the case when the agent is submerged in the liquid systems practicable in a wider range of temperatures.

It is another object of this invention to provide an ebullition system comprising a tank having a quantity of liquefied petroleum gas such as butane, propane, and the like therein, and a catalytic agent such as a piece of longitudinally porous rattan, bamboo, reed, or cellular woods, submerged in the liqueiled petroleum gas to produce boiling at a lower temperature than the liqueiied gases would otherwise boil. The longitudinally porous structure aids in the change of the liqueed gas to a vapor without itself .being inside the tank.

It is another object of thisV invention to produce ebullition of liquefied petroleum gasesby inserting into the liquid an ebullator comprising an elongated member having a plurality of minute longitudinal capillary passages extending from end to end. This may be a vegetable growth or it may be manufactured by some special process to imitate any vegetable growth having longitudinal capillary passages extending from end to end, the capillary passages being of such small cross-sectional area as compared with the length, so as to lower the pressure of the liquid at the central portions of the capillary passages to where it is much less than the pressure of the liquid at the ,open ends of the capillary passages.

Some of the objects of the invention having 3 been stated, other objects will appear as the de'- scription proceeds when taken in connection with the accompanying drawings, in which:

Figure 1 is a side elevation, partly in section, I

Figure 5 is an enlarged longitudinal sectional view with lthe central portion thereof broken away, and taken along the line 5-5 in Figure 4;

Figure v6 is a View of a portion of a piece of rattan, bamboo, or cellular wood in its natural state, from which the element for producing ebullition is cut;

Figure 7 is an elevation of a liquefied petroleum gas tank partly in section, showing a slightly modified form of the invention;

Figure 8 is a transverse vertical sectional view taken along the line 8 8 in Figure 7,;

Figure 9 is an enlarged sectional view ofthe lower right-hand portion of Figure '7;

Figure 10 is a sectional plan view taken along the line Ill-l0 inFigure '1;

Figure 11 is an elevation of another liquefied petroleum gas tank, illustrating another modied form of the invention;

Figure 12 is a transverse vertical sectional view taken along the line I2I2 in Figure 11;

Figure 13 is an enlarged sectional detail view of the right-hand central portion of Figure 12,

illustrating the manner of positioning the element for producing the ebullition relative to the main liquid body in the tank;

Figure 14 isan enlarged sectional view-taken along the lines Ill- I4 in Figures 12 and 13;

Figure 15 is anisometric view of a spring clip 58 employed for conning the ebullition element in position near the lower portion of the tank; Figure 16 is a view similar to Figure 13, lbut showing the ends of the ebullition element cut in a special manner so that spacer elements therebetween can be eliminated.

posed in housing 24. on the upper end of lpipe ls. The rising and :suing of the nquid ievei' s yactuates the float I8 which, in turn, actua-tes the pointer or indicator in the housing 2l tol cause it to rotate to diierent positions. When filling the above-described tank, a cap 2B is removed from the upper portion of the ll pipe land. fuel is conducted into the tank. At the saine time, the displaced vapor within the ta-nk is permitted to flow therefrom through a vent pipe 21. The details of the structure thus far describedcan be more completely understood by referring to my 'copending patent application Serial No.

473,555, led January 25, 1943.

As heretofore explained, butane mixtures such as used for domestic fuel have an initial theo- -retical boiling or evaporation point of approxi- Referring more particularly to the drawings,

, tank through a service pipe line I4, said pipe line extending upwardly through the interior of a ll pipe I5, and then to points of consumption. The service pipe line I4 is provided with a conventional excess flow valve I6 and a shut-0E valve I 1.

The tank is also provided with a conventional gauge for indicating the liquid level within the tank, this gauge comprising a float I8, disposed on one end of a rod I9, said rod being secured intermediate its ends upon a shaft 20. The shaft 20 has a gear 2l xed thereon, which gear meshes with another gear 22, said gear 22 being secured on the lower end of an indicating gauge shaft 23. Shaft 23 extends upwardly 'throughthe ll mately eighteen degrees Fahrenheit, and this is A* the point where suchl boiling barely starts when the temperature of the liquid is rising, or the point where the boiling stops when the temperature of the liquid is falling. Dueto the lack'of circulation or movement of the fuel disposed within the tank, this boiling to -any appreciable amount. actually ceases when the temperature fallsy to thirty-two or thirty-five degrees Fahrenheit. On account ofthe last-named temperature range be.

ing above some of the normal winter ground temperatures, the boiling ceases in the tanks in cold weather and gives considerable trouble. Of course, when the boiling of the fuel ceases, no vapor will be formed, and consequently, the service lline I 4 to the points of consumption cannot supply any fuel. The above example 'relates to butane mixtures, however, the present invention is not limited to this particular gas, because the same principle might be employed in association with other liquefied petroleum gases such as propane, and the like.

It is therefore evident that must be provided for producing ebullition or the boiling o f mixtures such as butane at lower temperatures than thirty-two to thirty-ve degrees Fahrenheit in order to make the .systems more operable during winter months.

In carrying out the present invention, it has been found that a longitudinally porous ebullition element such as a piece of rattan 30, or allied vegetable matter such as bamboo,'reeds,.cellular wood, or the like may be employed to accomplish this purpose. Since these woods possess similar characteristics, a description will be made in association with rattan in order to more speciflcally describe the operation of the invention. Rattan has been defined yby Century Dictionary as follows:

Rattan is any of the various climbing palms of the genus Calamus; any of certain low palms of the genus Rhaphis; also the tuft stems 'o'f such palms used for wicker work, canes, etc.; also a stock or switch of this material. l

Rhaphis or Raphis is any of the palms of the genus Raphia, as of tropical Africa and America Botanically speaking, raphia is one of the minute needle-shaped crystals of calcium oxalate which occur in the cells of many plants.

Calamus is a reed or cane (these two terms are now obsolete to describe Calamus) The sweet iiag, Acorus calamus, or its aromatic root; any palm of the genus Calamus yielding rattan,

canes,'etc. (cf. rattan and Malacca cane); also the quill of a feather. The above-mentioned ebullition element of rate some simple means c as rouia of Madagascar which yields rama fiber.y

tan 30 is cut from betweenloints 3| of a `stall:

or limb of rattan 32 such as disclosed in Figure 6. The piece 30 may be cut along any suitable spaced intervals such as long dotted lines 33 provided the piece has the joints eliminated therefrom. Where a joint is present, the capillary passages in the rattan limb are very much restricted in size, if not entirely closed, but the capillary passages 36 have substantially the same size throughout the entire length of material between the severing lines 33.

When a piece of rattan 30 is cut from the stalk 32, the natural skin 34 is permitted to remain thereon to thereby seal the inside core portion 35 of the rattan element. In other words, the natural skin 34 is of a hard non-porous nature, whereas the inside core portion 35 is of a `softer material. This intermediate core portion of element 30 has a large number of longitudinal microscopic capillary passages 36 therein extending from one end to the other of the element. The cross-sectional diameter of these passages will range from one-thousandth to three-thousandths of an inch, depending upon the outside diameter of the piece of rattan used. Such pieces of rattan as used usually range in size from threeeighths of an inch outside diameter by four inches long to three-fourths of an inch in outside diameter by twelve inches long, and, of course, these pieces are cut from between the joints and have a cellular structure'comprising a series of natural longitudinal passages which continue from one end to the other. However, I desire it to be understood that any size of ebullator may be used.

On account of the small diameter of capillary passages 36 as contrasted with relatively long length of the columns of liquid contained within, there is a pressure differential between the central portion of each passageway and the points where the liquefied petroleum gas enters these passageways. In other words, the pressure on the ends of-the liquid column within the passageways might be two pounds to the square inch, and the pressure at the center of the column within the passageway might be only one and one-half pounds per square inch. This pressure differential is due, in part, to the capillary action or friction existing between the liquid and the wall of the passage, said capillary action creating a friction which tends to lower the pressure at the longitudinal center of the liquid column.

This pressure differential is 'similar to that existing in pipe lines and is due to an exactly simiy to cause it to boil at a much lower temperature lar action, and is a well known phenomenon.

For example, the longerv the pipe in a water main, the greater will be the friction loss, which will reduce the effective water lhead at the point of distribution. Therefore, the pressure might be one hundred pounds per square inch where the water enters a main and only sixty pounds per square inch at the point of distribution, the loss in head resulting from friction. Each microscopic passageway 36 through the rattan element 30 is, in effect, similar to such a pipe line and it follows that the action therein is similar.

This difference in pressure existing within the microscopic column of liquid disposed in the passages 36 enables boiling or evaporation of the liquid to start at the center of the columns before it will start at the ends of the columns and in the surrounding liquid. It is a well known fact that there is a very definite relationship besure `will be less at the center of each passage 36, a condition is created where the liquid will boil at this low pressure area before it will boil at the surrounding points which are under a greater pressure.

Since rattan, bamboo, reeds, cellular wood; palm stems, and similar vegetable fiber in their natural state are usually of a porous character, and usually have a lower specific gravity than liquefied petroleum gases il, these woods will oat unless they are weighted or otherwise prevented from floating. In the present form of the invention, each piece of rattan 30 has a pair of spaced metallic washers 39 secured therearound, said washers serving to space the rattan from the bottom of the tank and also serving to weight the piece of rattan suiliciently to prevent it from oating.

As an example, consider a condition where liquefied butane gas is disposed in tank I0, and where the boiling has ceased when the temperature has dropped to thirty-four degrees Fahrenheit. Theoretically, this mixture should boil until a temperature of eighteen degrees Fahrenheit has been reached, but as heretofore stated, due to the quiet state of the liquid, the boiling will cease at a much higher temperature. 'I'he purpose of this rattan element 30 is to cause a boiling of selected columns of liquefied gas which will, in turn, agitate the main body of the liquid than thirty-four degrees.

In the above example, when the temperature reaches thirty-four degrees and the boiling ceases, the vapor pressure in space I2 within the tank is zero pounds per squareinch or atmospheric pressure. The pressure within the liquidv body Il outside the rattan element 30 is therefore zero pounds per square inch or atmospheric pressure plus the depth pressure, and'this depth pressure in shallow tanks such as shown is so small that it may be disregarded. The pressure on the ends of the columns of liquid contained within each rattan passagel 36 is likewise zero pounds per square inch or atmospheric pressure, but the pressure at the center of said column will be considerably less than the pressure that prevails in the main body of the liquid outside 'the rattan element. The liquid at the center of the column of the liquid within each passage 36 will therefore start evaporation first to cause gas bubbles to be ejected from the ends of each of these pores, said bubbles rising after escaping from the passages through the main body of liquid Il and serving to agitate it to thereby cause the main body of liquid to start evaporating or boiling at a point more vnearly to or at its initial boiling point, which in the present example, has been designated as eighteen degrees Fahrenheit for butane mixtures.

Particular attention is called to the fact that the elements 30 when comprised of rattan, bamtween pressure and boiling point.l In other words,

boo, reed, or the like have the natural skins 34 thereon. This natural skin is very hard and nonporous and therefore seals the core portion against leakage.V The lpressure differential between the main body of liquid H and the centers of passages 36 could not exist if radial leakage from the passages were permitted. Since -the inner core portion 35 of the wood is of a softer material, it naturally follows that a certain amount of leakage would be permitted werel it not for the natural non-porous skin .34 which encases the entire assembly of longitudinal passages 36. 1t is therefore seen that the natural vskin 34 sameeffect would be produced, however, the con struction of such an element is costly, especially when vegetable material, such as bamboo, reed, l rattan, and the like are available at low cost.

It is therefore seen that the elements 30, regardless of the material from whichthey are formed, clearly act as a catalytic agent. A catalytic agent is defined in chemistry as a material that aids chemical action without itself being permanently changed. These catalytic agents are commonly called ebullators.

In explaining the operation of the present invention, attention is called to the fact that vaporization is believed to mean the conversion of a substance into the gaseous form. If the change takes place slowly from the surface of the liquid, it is called evaporation, but if the liquid is visibly agitated by rapid internal evaporation, the process is called ebullition or boiling. The rattan, bamboo, reed, cellular wood, or other elements 30 act at ebullators, and bring about the latter process.

Figures 7 to 10 inclusive show a slightly modi- Vfled form of the invention in which the holding means for the' ebullition elements 36 is a built-in part of the storagetank in which the ebullition process is augmented, said holding means comprising tubes or pipes, welded to the lower portion of the tank. Specically, the numeral 45 denotes a tank having a plurality of vertically disposed tubular pipes 46 extending downwardly from the lower portion thereof. There is also vertically disposed end pipes 41 extending downwardly from the lower portion of the tank, said pipes 46 and 41 having their lower ends joined by a longitudinal header pipe 48. The pipes 46, 41, 48, as well as tank 45 are buried in the earth 49.' A. piece of rattan, reed, bamboo, cellular wood, or similar ebullition element 30 if, inserted into each of lthe vertically disposed pipa-s 46, .and each of these elements are held in position within its respective pipe by any suitable means such as a spring clip 50. The end pipes 41 do not have an element 30 disposed therein.

The ebullition action of the elements 30 within the pipes 46 causes the liquefied petroleum gas Il within the tank to be drawn downwardly through Vend pipes 41 and then horizontally .through header pipe 48,from whence it passes upwardly through the ebullition elements 30 within pipes 46, and is finally ldischarged into the main bodyof liquid in the tank 45. The liquid in the passages 36 of the elements 30' is formed into bubbles on account of the pressure differential, and these bubbles pass upwardly through the main body of the liquefied petroleum gas Il to thus produce the desired ebullition such as described in the preceding form of the invention. i y

In the present form of the invention, the earth temperature will more directly affect the liquid within pipes 46, 41, and 48, as well as affect the temperature of the elements 30 disposed within `perature in cold weather will be much higher .than at shallower depths. Therefore, such a system will provide a means whereby the ground temperature can be more favorably employed in cold weather to augment or agitate the main body of liquid Within the tank.

Such a system is designed to give a more violent bubbling and agitating eiect to the main body of the liquid, thus achieving more complete vaporization of the main body of liquid at lower temperatures than in the conventional systems. Figures l1, l2, 13, 'and 14 show s`till another vmodified form of the invention in which the holdf ing means of the ebullition elements 30 are also a built-in portion of the tank, but of a dierent design. vIn this form, the numeral designates` a tank for"liqueed petroleum gas Il, said tank having the ends .of a plurality of spaced circular pipes 56 communicating therewith as at 51, A plurality of ebullition elements 30 are loosely fitted within each pipe l56, said elements being con-v ned .therein and prevented from floating into the main body of the liquid Il by any suitable means such as circular spring clips 58.

I These spring clips 58 have inturned leg portions 58a, said inturned portions serving to coniine the uppermost ebullition element 30 within the pipe 56, and also serving as projections which may be engaged by a suitable clamping .element when it is desired to contract the/clip to remove or insert the same in position within the pipe.

y Attention is called to the fact that suitable spacer members such as compression springs 60 are provided between adjacent ebullition elements 30 within pipes 56` These elements prevent the cut ends of the elements from abutting and thus cutting off liquid contact. As an alternate method of preventing liquid contact from being cut. off at the ends, the ebullition elements may be cut in .the manner shown in Figure 16. In this form of the invention, the ebullition element isl designated by reference character 62, and one end of each element is pointed or cut on a bias as at 62a, said bias portion being adapted to provided with a similar manhole 55a which is employed for the same purpose. It is to be understood, however, that the employment of these the pipes 46 than in the preceding form 'of theinmanholes is an optional feature, because the ebullition elements 38, in many instances, may be inserted or removed through the stand .pipe attachment hole by employing a long handled gripping tool.

The circular pipes llili always communicate with the main body of liquid and will therefore remain lled so that the ebullition -action of the elements 3U will form vapor bubbles.

lThis ebullition action is greatly augmented by the heat of the surrounding earth 48, and therefore, bubbles or Vaporization within the elements will be formed at a faster rate than in the iirst form of the invention, wherein theebullition elements are deposited within the lower portion of the main body of the liquid. The bubbles which are formed within the circular pipes 56 are permitted to escape as at 5 1 into the main body of the estense liquid l l, and thus agitate this liquefied petroleum gas to cause boiling to take place at e lower tem pereture than it would otherwise boil.

In the drawings and specification, there has been set forth a, preferred embodiment of the invention and although specific terms are employed, they are used in a. generic and descriptive sense only and not for purposes of limitation, the scope of the invention being dened in the claims.

ll claim:

v 1. The method of promoting veporizetion in e confined body of liquefied fuel, which includes submerging in said body one,or more rods each comprising e. jointfree portion of ratteniike plant metter and having the capillary passages et the end of the rod open for penetration by the lionen ed fuel end the portions between the ends pro= tected by the neturel skin of the plant.

2. The method of promoting vaporizetion in e. s

confined body of liqueed fuel, which consists in drawing fuel vapors from seid body and et the same time exposing the iuel to' the capillary ection of the natural plant passages of one or more submerged rods, each comprising a jointlree por tion of e, steil; of rettenlilse plant metter and having the portions between the ends of the rod protected by the naturel slain of the nient., v

lil

nismsnnuoes einen The following references are of record in the Number Name Date l.,917,154 Porter July 4, 1933 1,931,268 ,Philipp Oct. l?, i933 2,121,6'l5 White June 2l, i938 1,298,821 Nordell Dec. i9, 1.9i@ i,23,079 Andrews Sept. l5, i931 1,929,511 Mulkey Oct, i0, 1933 2,1%,367 Mead Feb. 13, 19450 2,332,349 Schulz Ooi; 19, i943 2,255,584 Hubacker l.- Sept. 9, 194i.

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