US2463477A - Gas dispensing device - Google Patents

Description

March l, 1949a w. c. BUTTNER GAS DISFENSING' DEVIGE 5 Sheets-Sheet 1 Filed oct. s. 1946 tQN - INVENTOR. 'MW/0527 a//fze/f March l, 1949..` 'W, C, BUTTNER 2,463,477

GAS DISPENSING DEYTCE Filed Oct. 3, 1.9 46 3,. Sheets-Sheet 2 3.9 n l ya IN VEN TOR.

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March l, 1949., w. c. BUTTNER 2,463,477

GAS DISIENSING DEVICE 3.8)16'etS-She't 3 Filed oct. s. 1941sl 1N VEN TOR.

' its preliminary expansion so `system this heat absorption exothermic reaction Patented Mar. l, 1949 2,463,411 Gas Drs'rnNslNG nnvlcr;v

William C.

Buttncr, Winnetka, Ill., The Bastian-Blessing Company, Chicago, a corporation of Illinois assignor to Ill.,

Application October 3, 1946, Serial No. 700,861

The present invention relates to iiqueiled'gas dispensing systems and more particularly `to a means by which a combustible gas stored in its liquid phase may be vaporlzed in a novel and improved manner anddispensedat a service pressure for use as a fuel in an appliance.

The petroleum product that this'system is designed to handle is preferably a hydrocarbon of the paraflln or olefin series, such as butane, propane or butylene or various mixtures thereof having boiling points below average atmospheric temperature. These fuels are usually stored in their liquid and vapor phases in closed containers and the vapor pressure of the fuel is utilized to move fuel from the container to a point of consumption. In its transition the fuel is expanded, and if not already vaporized, it is vaporized after that the fuel delivered to the appliance is in its vapor phase and at a service pressure.

There are two general types of systems employed. One a .batch system where vapor fuel is withdrawn from above the liquidin the tank and passed through a pressure reducing regulator to the appliance using the fuel, and the other the so-called flash system in which liquid fuel is withdrawn from the bottom of the tank and passed through a pressure reducing regulator and supplied with the latent heat of vaporization to vaporize it at its reduced pressure.

Wherever the vaporizaton takes place the available heat' is absorbed by the gas from its surrounding parts either from its own liquid body or metallic bodies of its controls. In the `batch is largely expended in the tank, whereas with the flash system the heat absorption is confined to a comparatively small area around or beyond the regulator and its connections such as the service line.

The dispensing system of the present invention is similar in many respects to the embodiments .disclosed in the copending application Serial No. 539,6'70filed by William C. Buttner,

Harold L. Norway and Jerome R. Bunce, Jr.. June 10, 1944, incorporation of which is hereby made. u

One of the objects of the present invention is to provide an improved vaporizer for liquefied petroleum gas wherein the latent heat of vaporization is derived from a. controlled Vcatalytic for standbyl and peak load operations in an efficient and safe manner.

Another object of the invention is to provide a liquefied petroleum gas vaporizer supplied with the latent heat of vaporization required at any given time throughout winter,-summer and gale conditions without freezing up and without going out.

Another object of the invention is to provide an improved flash system whereby two pressure reductions are made on a flowing stream of fuel and heat is supplied to the flowing stream in an improved manner between the two pressure reducers to assure vaporization of the fuel so that only dry gas will be delivered to the consuming appliance.

Another object of this invention is to provide an improved dispensing system in which a portion of the latent heat of vaporlzation is sup plied to the stream of fuel by withdrawing and catalytically'oxldizing a minor fraction of said stream to produce heat, and transferring this heat to said flowing stream at a point upstream of the withdrawal point.

Another object of the invention is to establish andfutilize a large amount of radiant heat which is transferred from a catalyst bed to a flowing stream of liquefied petroleum gas simultaneously with the convective transfer of heat from the oxidation products passing upwardly through the bed.

A further object of this invention is to provide an improved vaporizer for flash or batch vaporization systems in which no flame or spark is present which might initiate an explosion. The heat of vaporization being obtained by reacting a mixture of -fuel and air in such proportions as would be non-explosive.

A further object of the invention is to provide a vaporizer in which the catalyzer bed is` maintained at the required activation temperature by a smaller pilot heater which is also catalytic.

Another object is to provide a vaporizer'having a catalyst bed in which the same kind of fuel as that dispensed is utilized to generate heat, the flow of fuel to said bed being controlled by a temperature responsive valve responsive to the temperature of the flowing stream after the rst stage pressure reduction so that large amounts `from this cabinet 2| y 3 net and the preferred disposition of the various elements therein. j v Fig. 3 is a schematic view of the dispensing system. v

Fig. 4 is an enlarged section of the lower portion of the vaporlzer, and' Fig. 5 is a section showing one form of `a temperature responsive valve.

This invention will be described in connection with a "ilash system of vaporization because its localized latent heat of vaporization requirements are the highest. However, it will be apparent to those skilled in the art that the vaporizing system of this invention may be readily adapted to a batch system and used as a revaporizer to eliminate any condensation formed in the service conduit. s

In the flash system liquefied fuel is forced from a storage tank by the vapor pressure o1' the stored gas and passed through a first stage pressure reducing regulator to reduce its pressure and allow a portion of the fuel to vaporize. Further vaporization occurs to the extent that heat is available at that point in the system to supply the latent heat of vaporization. For the purpose of supplying any deficiency in the available latent heat of vaporization, which may exist beyond the first stage pressure regulator due to a sustained or heavy consumption of gas, a vaporlzer is provided which catalytically oxidizes a limited amount of the yaporized fuel to produce-thev latent heat of vaporization required.

The heat is generated inthe vaporizer by a catalytic bed which glows red without flame. 'I'he radiant energy of the bed is picked up by a ue having a blackened inside wall and the hot by-fproducts of fled to contact the flue wall also. In carrying out the preferred form of the invention, the fuel vaporizlng coil is spaced from the wall of the flue a distance sumcient for a closed body of fluid, such as air, insulated from outside temperatures, to now convectively over the outer wall ofthe flue and then over the coil turns. The coil is shielded from the hot flue at its spaced position by means of a cylindrical sheet of asbestos 'to assure the convective circulation, and the ar.- rangement prevents moisture collecting around the coils at the same time it also prevents condensation occurring in the ilue. Similarly an anti-freeze solution could be employed instead of Referring now to the construction embodying the invention and Fig. 3 particularly, a spherical storage tank l is shown in Fig. 1 mounted on hollow legs ii and I2. provided with a padlocked door i 3 affording access to a fitting I4 such as that shown in Patent No. 2.361.865 granted to Harold L. Norway, hereby incorporated by reference'. This fitting I4 provides a means for filling the tank i0 as well as withdrawing liquid fuel I from the bottom of the tank Ill and includes an excess ow check valve and shut-off valve (not shown). A protective cover I8 is shown on top of the tank I0 which contains a pressure relief safety valve and a liquid level gauge (not shown).

From the fitting i4 a high pressure conduit I1 extends under the ground i8 to a rpoint near a building where it rises into an insulated cabinet containing the pressure reducing regulators 22 and 23, the vaporlzer 24 and various controls to be described. A service conduit 25 extends to the appliance 28 using this fuel. A manually operated shut-oi! valve the oxidation reaction are bai-- 4 21 is providedA in conduit where it enters the building 2li.V

The disposition of the various elements within the cabinet 2| and the construction of the vapors izer 24 are best shown in Fig, 2. The high pressure conduit I1 enters the cabinet 2| through a hole 23 provided in the bottom and leads to the first stage pressure reducing regulator 22. The intermediate pressure conduit 30 extends upwardly tothe temperature responsive valve 3| where the conduit 30 is wound around the temperature sensitive The temperature responsive erably of the "snap action" 15 opened when subjected to a temperature below a certain point and is closed when the temperature is above that point. In some instances, however, a variable valve. such as that illustrated in Fig.v 5, has been found desirable.'

20 From the turns 32 the conduit 30 extends downwardly into the vaporlzer 24 where itis connected to a heat exchanger coil 33. Another conduit 34 connects the other end of the coil 33 and a tra/p 35 which serves to collect any moisture or heavy fractions preferably at the lowest point in the conduit 38 leading into the service stage regulator 23, which conduit is connected to the regulator by an L fitting 3s in weight supported relationship.

The outlet of the second stage regulator 23 in turn is connected to the service conduit 25 by a T fitting 31 while the remaining opening receives a second T 38 connected by means of a nipple 40. From this second T 38 two conduits 4| and 42 extend downwardly to the bottom of the vaporizer 24. One conduit 4i leads directly to the pilot port 43 and the second conduit 42 is connected to the temperature responsive valve 33 from which the conduit 44 extends to the bottom of the vaporlzer 24 where it ends in a gas mixer valve 3| is preftype which is fully An air inlet pipe 48 extends from outside the cabinet 2| to the base casting 41 of the vaporlzer 24 and an exhaust pipe 43 extends from the top ofthe vaporlzer 24 to a point outside the cabinet 2|. Each of these pipes 48 and 48 is provided with devices such a caps 50 to allow tl-.e passage of gases and prevent the entrance oi' moisture or snow in the flue 49.

'I'he exhaust pipe 48 is shown in the drawings to lie horizontally. If this pipe 48 were vertical, condensing of moisture in its upper end could drain back into the vaporlzer to cool the catalyst bed and stop the reaction. Where operation in tageous to have this pipe 48 slope downwardly with the outlet below the top of the vaporizer 24 so that any liquid formed will drain out of the pipe 48. The bottom of prises a base casting 41 secured to the floor of the cabinet 2|. A plurality of tubular shells such as metal housing 52 and an asbestos partition 53 extend upwardly therefrom and receive at their top a closure comprising a casting 5|. Two annular spaces 54 and 55 are thus formed by the tubular members, the outer one of which receives the coil 33 against the outer face of the shell 53 and the inner one of which is adjacent to the flue 49. This arrangement allows the convective cirthese spaces upward through the inner space over the outer surface of the flue 49 and downward in the outer space over the coil 33. The asbestos shield 53 prevents any substantial amount of 15 heat being absorbed during said upward moveportion of the valve 3i as at 32.

cold climates is encountered, it has proved advanthe vaporlzer 24 com' culation of antifreeze fluid or air contained in I -iiowing from ment o! said huid so thatconvective circulation is assured and the temperature ci the nue wall is ept above the dew point of the hot gases in the ue. The base casting (Fig. 4) approximately cylindrical in shape, is provided with a hollowed out central portion 59 open at its upper end and apertured to receive the inner end of the air inlet pipe 44. An externally threaded boss 51 is provided at the bottom of this cavityto receive the tube I9 of the mixer 45. A drilled passage 89 extends from a suitable fitting 5I on the side of the casting 41 to the orifice passage 42 which is drilled from the top oi the boss l1. The mixing tube 59 extends upwardly through a plate Il which seals the top of the cavity -from the lower end of theiiue. The walls of the casting 41 extend upwardly beyond this plate I9 and support a second periorated plate or screen 94 on which the catalyst pellets ,l5 are retained. An external shoulder 5l on the base casting 41 is also provided which supports the ue 49 and a grooved ring `91 which in turn supports thefouter shell 52. The groove 99 in this ring 91 receives the lower end of the baille shell 59 between the flue 49 and the outer shell 52. The baille shell 59 carries the heat exchanger coils $3 which may be fastened thereto by brazing or soldering or by other suitable means. In certain applications it has been found desirable to provide a metal baille shell to support the asbestos partition. In fact an asbestos coating on a metal 'shell is very good for the partition when the asbestos is located next to the coils I3 to promote thci convective circulation of the heat exchange il d.

A second tting 10 is screwed tinto a hole' 1I in the sldeof the casting 41 and a passage 12 con nects this hole 1| with atube 13 leading -to the pilot heater 43. This heater 49 consists of a periorated enclosure containing platinized or palladiumized asbestos 14. The annular spaces 54 and 55 may either contain an antifreeze solution or air as a heat transfer medium.

In Fig. 4 the pilot heater 49 is shown supported at the same level'with the screen 94 holding the catalyst bed 65, but in some instances it has been found advantageous to locate this heater 49 below the screen 64. A second ring (Fig. 2) is supported by the upper ends of the outer shell 52 and flue 49 and carries the top casting 5| which is hollowed out as indicated to provide communication between the nue and the exhaust pipe 4l. The baille shell 59 is supported in a groove 19 inthe ring l5 and is provided with a plurality of holes 'I1 at the top, as well as a second plurality 19 at the bottom so that the two annular spaces 54 and l55 are in communication with one another at both the top and bottom oi the vaporizer 24. This is done so that a convective circulation of air or antifreeze solution will occur through these annular spaceswith respect to the flue and the coils 93 when the vaporizer 2'4 is in operation. A number `of horizontal baille plates 80 are supported by brackets 8| within the flue 49 and serve to inhibit the passage of hot gases through the ilue 49 until much of their heat has been transferred to the ilue wall.

The mixing tube 5l is so constructed and arranged that a plurality or holes l5 are provided in the side wall of the tube 59 through which air is `drawn by both the circulationinduced by the pilot heater and the'pressurized stream of fuel gas the tube 59 through the orifice 92. The diameter of this oriilce 92 is such that the rate oi gas iiow after it leaves this tube 59 is combustion are `jacket is sealed greater than the rate ot name propagation of the fuel being used. Thereby ignition in the tube il cannot possibly occur even if a llame were introduced from the outside through .one of the holes 9 5. Any llame produced would have to travel upwardly in the tube 5I and would pass the point where the gases are completely mixed. Above this point the mixture, as has been stated, would be too lean to support combustion.

If propane or butane is burned in air, the percentages oi fuel to air required for complete iiame respectively 3.85% and 3.08% by volume. If more fuel than this amount is used,

. it will not be completely burned. The explosive or combustible range of these two gases varies from 2.4% to 9.5% for propane andy from 1.9% to 8.5% for butane. the range of name combustion, preferably upon the lean side for the sake of economy.

Referring to the alternate type temperature responsive valve 3Ia as shown in Fig. 5, this valve depends on the principle of utilizing two metals having different coefficients yof thermal expansion to vary the opening position of the valve member 98 with respect to a port 99. The valve 9Ia comprises a tubular iiuid jacket 99 equipped with a iluid inlet Vill and outlet 89. The upper end of this tube is provided with external threads 90. for attachment to the valve body 9i. A flexible metallic diaphragm 92 is retained against a shoulder' 99 in the body 9i by the end of the jacket I6 and serves to seal the cavity 94 in-the valve body 9| from the jacket 99. The other end of the by a gasketed cap 95. The jacket 9K9 is made of brass, stainless steel. or other metal having a small coefilcientv oi' thermal expension.

sage 95 which`extends from the top to the valve` port 96 opening into the cavity 94. An outlet passage 91 extends outwardly from the chamber 94. The valve member 991s urged away from the port 96- by a spring |00 which bears against the end of the cavity 94 and a flange IIII on the lowerend of the member 98. The upper end of the member 99 is recessed'to receive the valve disc |92 which is preferably formed of nylon or a material having similar physical properties.

Disposed within the jacket 96 is the operating member |93, preferably formed of aluminum or other metal having a high coefcient of expansion. The member |09 bears against the lower face of 'the exible diaphragm 93 and an adjusting screw |04v provided at the bottom of the jacket 96. The flange |05 is provided to hold the upper end of the rodlike member |09 inl axial position.

When this valve lia is used in the dispensing system, the helix 32 is eliminated and the conduit 39 is connected to the openingsl 91 and 89 in the jacket 89 so that all uid passing through the conduit passes through the jacket 45. The passage is connected to the conduit 42. and the outlet 91 is connected to the conduit 44 leading to the mixer 45.

Variations in the temperature of the stream of gas and liquid -leaving the nrst stage pressure reducer 22 cause the member |03 as well as the jacket to expander contract, but since the coelcients oT expansion oi'the two metals are diflerent, a change in temperature causes the end oi the member |09 to assume a varied position with respect to the t'opoi the jacket 96 and the diaphragm 92. Since the diaphragm 92 is iiexible this movement is transferred to the The invention operates outside of 7 valve member Il and permits the fuel to flow in varying amounts dependent upon the temperature of the gas in the service line.

The operation of this dispensing system is as follows:

As fuel is consumed by the appliance 28. the vapor pressure of the liquid il in the tank il forces liquid to pass through the underground conduit i1 to the first stage pressure reducing regulator 22 in the insulated cabinet 2l. As the liquid fuel passes through this regulator 22 the pressure is greatly reducedwith the result that a portion of the fuel is flashed into vapor and simultaneously expanded and chilled. Some heat is supplied at this point .to the chilled liquid from the walls of the regulator 22 and conduit I to vaporize further fuel. Any fuel remaining unvaporized in the service linerpasses along with the vapor through the turns I2 surrounding the temperature responsive valve II where the temperature sensitive portion of the valve 2| is brought to substantially the temperature of the fuel stream. Ii' the fuel is cold enough, say 40 F. for butane, the valve il will be opened to allow a full supply of fuel at service pressure' to flow to the catalyzer bed 65 in the vaporizer 24 as controlled by the restricting effect of the passage l2.

After leaving the turns 32 the wet gas stream passes into the heat exchanger coil 32 in the vaporizer 24 where heat is transferredto. it by radiation and convective circulation as already described, and the remaining liquid present is vaporized. From ances.

0n leaving this regulator 2l the major portion of the vapor stream passes through the conduit 2B to the gas consuming appliance 26 within the building 20. A minor portion of the stream passes into the T 38. Two streams of gas leave this fitting 2l. One stream flows at a rate of approximately one tenth of a cubic foot per hour through the conduit 4i to the pilot heater le. The volume supplied to this catalytic heater 14 is just suiiicient to maintain a portion of the main catalyst bed 86 above the activation temperature or that temperature at which catalytic combustion will occur. This temperature varies the fuel dispensed, but a temabove the minimum requireall cases the temperature provided is considerably below the ignition temperature of the fuel. so that the danger of overheating and ignition or flame combustion is entirely eliminated.

A second stream of gas leaving the T tt'ing 28 passes through the temperature responsive valve 3i, during the time that this valve is opened, to the main supply mixer 46 of the vaporizer 24. The gas stream enters the mixer 45 through the passage Bil. jThe rate of flow through this passage is regulated by the size of the orinee I2 and the pressure setting of the second stage regulator 22. A constant velocity stream of gas therefore passes upwardly through the tube il. Air enters through the holes' and is mixed with the gas stream in the tube 58. The mixture then passes through the catalyst bed .85 where it is oxidized to release heat and hot gases upwardly into the flue Il. Radiant heat ture actuated -iiue and the passage of the hot of the gases is slowed down by the baiiies 0l so that their heat is* transferred to the wallspf the nue 48. 'Ihus the-air or antifreeze solution in the annular space all is heated. This heat transfer medium rises .by

convection to the top of the space l5 where it. passes through the holes 'l1 into the outer annular space 5I flowing downwardly over the coils Il and heating the stream of fuel flowing through them. The descending cooled medium then passes inwardly through the holes 18 at the bottom and back into the inner space Ill where it is reheated. The recirculation of the same medium,

in event it is air as shown, .avoids condensation problems. Furthermore, the fact that the hot gases do not comeinto direct heat exchange con-` tact with the cold coil 22 eliminates condensation in the flue.

In view of the fact that the pressure in the conduits and coil between the first and second stage regulators is governed by the first stage regulator and is constant, the temperature of the stream of vapor and liquid flowing through these conduits is constant as long as-unvaporid liquid is present in the stream. Any heat applied will merely serve to vaporize liquid rather than raise the temperature. Thus, heat can be supplied as long as liquid is present in the line at a constant temperature setting. f

Consequently, it is possible to use a temperavalve 3Ia which does not have a snap action and still achieve a substantially constant rate of flow of fuel to the burner 4I at the vaporizer 24. This is accomplished -by using a valve such as that shown in Fig. 5 having a port 88 at a relatively large cross sectional area compared with the area of the orifice 82 in the mixer 4l. By this means a very slight opening of the valve lla allows sufficient fuel to pass that no appreciable pressure drop occurs in the valve I la;

In practice the pressure at which the temperature responsive valve Il opens is set at a value a few degrees above the equilibrium temperature for saturated vapor of the fuel being used at the pressure setting of the first stage regulator 22.

Therefore, when no fuel or only a small amount is being used in the appliance 28. the rate of heat transfer through the walls of the regulator 22 and the conduit 20 is sufiicient to supply all the latent heat of vaporization required and the fuel stream through the turns 2| or the Jacket 86 is at a temperature well above that at which the valve 2i is set to open, the extra supply to the vaporizer is turned oil'. However,

from the glowing bed warms the wall when the load used by the appliance 28 is instream will quickly fall below the setting of the in the objects and the description, the scope of which is commensurate with the appended claims.

What is claimed is:

1. For use in a liqueed petroleum gas dispensing system a vaporizer comprising a ue, a.

catalyst bed disposed at the lower end of said flue, an annular space containing a fluid medium surrounding said flue, a second annular space surrounding and in communication with said first mentioned annular space, a conduit coil disposed in said second annular space, and means for supplying a mixture of fuel gas and air to the bottom of said flue below said catalyst bed. 2. For use in a liquefied petroleum gas dis- 3. For use in a liquefied petroleum gas dispensing system a vaporizer comprising a flue, a catalyst bed disposed at the lower end of said flue, an annular space containing a iiuid medium surrounding said iiue, and having a wall dividing the space into two compartments in communication with each other at the top and bottom, a conduit disposed in said space in the compartment remotev from the flue, and means for supplying a mixture of fuel gas and air to the bottom of said flue below said catalyst bed, said conduit being a. portion of a service line conducting liquefied petroleum fuel from a place of storage to a point of use.

4. In a vaporizer for use in a liquefied petroleum gas dispensing system the combination including a flue, a catalyst bed disposed at the lower end of said flue, a pilot catalyzer bed disposed in intimate relationship with the first bed, a service conduit for liquefied petroleum fuel disposed in heat exchange relationship with said flue. and means for supplying a mixture of air and fuel gas to said catalyst beds in a ratio less than that supporting flame combustion, said means comprising a mixer for admitting a stream of fuel gas and air below said first bed,

35 warmed catalyst 50 Number and an element for supplying a separate stream of said fuel gas and air tothe pilot bed continu- I ously.

5. The method of dispensing liquefied fuel comprising educting a stream of liquid fuel from a container, reducing the pressure to vaporize a portion thereof, supplying heat to the stream to vaporize the remainder,l reducing the pressure to a service pressure, withdrawing a portion of the flowing stream at service pressure, mixing thewithdrawn portion with air, oxidizing the resultant mixture in the presence of a catalyst to supply heat to a larger catalyst bed, and withdrawing a second portion of the flowing stream 1'5 intermittently when required, mixing said second portion with air and oxidizing it in said larger catalyst bed to produce heat which is supplied to said flowing stream after said first mentioned pressure reduction.

6. The method of dispensing liquefied fuel comprising educting a stream of liquid fuel from -a container, reducing the pressure to vaporize a portion thereof, supplying heat to the stream to further vaporize same, reducing the pressure to a service pressure, withdrawing a portion of the flowing stream at service pressure, mixing the withdrawn portion with air, reacting the resultant mixture of fuel and oxygen from the air in the presence of a catalyst to warm a catalyst bed, and withdrawing a second portion of the flowing stream intermittently when required, mixing said second portion with air and reacting it in said warmed catalyst bed to produce heat and transferring the heat produced in the bed to said educted stream ahead of said reduction to service pressure.

'1. The method set forth in claim 6 wherein the withdrawal of said' second stream is controlled in relation to the temperature of the flow- 40 ing stream at a point ahead of said reduction to service pressure and ahead of the point at which said transfer of heat occurs.

WILLIAM C. BU'I'I'NER.

REFERENCES orrED UmTED sTATEs PATENTS Name Date Re. 20,091l Knox Sept. 1, 1936 1,906,335 Rathourn May 2, 1933 1,948,298 Howard Feb. 20, 1934

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