US2163871A - Method of generating gas - Google Patents

Description

June 27, 1939.

A. J, DIESCHER METHOD OF GENERATING GAS 2 Sheets-Sheet 1 Filed Dec. 30, 1957 1 m h fi INVENTOR fl/f/ e J D/esc/rer ATTORNEY June 27, 1939. A. J. DIESCHER METHOD OF GENERATING GAS Filed Dec. 50, 1937 2 Sheets-Sheet 2 INVENTOR fl/fia am/ 8:

ATTORNEY Patented June 27, 1939 PATENT OFFICE METHOD OF GENERATING GAS Alfred J. Diescher, Winfield, Kans., assignor to B. E. Hepler, New York, N. Y.

Application December 30, 1937, Serial No. 182,633

2 Claims.

This invention relates to a method of generating a gas, and particularly to the enrichment of air with vapors of a normally liquid hydrocarbon such as a volatile distillate, for example gasoline. Individual apparatuses of this character are particularly useful for supplying gas in rural and suburban districts where conven tional gas supplies are not available for cooking, heating and similar domestic purposes. While there is a large potential market for such apparatus by reason of readily available supplies of a suitable liquid hydrocarbon, they have not proven successful because of ineiliciency, danger of explosions and difficulty of adjustment and operation. These difiiculties have been brought about primarily by variation in prevailing atmospheric conditions and in contact time of the air with the distillate due to varying levels of the contacting liquid in the apparatus. These variable factors control the B. t. u. value of the gas for a given hydrocarbon and constant air supply. Tests have shown that full saturation of air with distillate vapors drops rapidly as the temperature at the point of enrichment lowers. Therefore when the apparatus is set to supply a gas having sufiicient vapors or B. t. u. content to keep the gas above the combustion or explosion range, drop in temperature results in lowering the B. t. u. value into the explosion range and flash-backs are likely to occur. Likewise, should the temperature rise at the point of enrichment, condensation occurs in the lines and burners which interferes with efficient operation. Gradual consumption of the contact liquid shortens the contact time of the air and also results in gradual drop of the B. t. u. value, which is apt to bring the gas within the explosive range. Wide variation in the B. t. u. content of the gas also interferes with burner adjustment and combustion elliciency.

It is, therefore, the principal object of the present invention to provide a method of enriching air with a volatile hydrocarbon which is' efficient and safe in operation.

Other objects of the invention are to provide a constant supply of uniformly enriched gas which is kept above the explosion range of an air vapor mixture and preferably slightly below the full saturation point; to maintain a constant temperature in the zone of enrichment regardless of variation in atmospheric conditions; to secure a uniformly intimate contact of the air and contacting liquid over an ample period of time regardless of the level of liquid carried in the apparatus; to prevent condensation in the lines leading from the generating apparatus to the point of use on moderate temperature changes; and to permit the use of smaller pipes,

valves and other fittings between the enriching unit and the burners by reason of greater efliciency.

In accomplishing these and other objects of the invention, as hereinafter pointed out, I have provided improved details of structure, the preferred forms of which are illustrated in the accompanying drawings, wherein:

Fig. l is a vertical section through a gas generating apparatus constructed and operated in accordance with the present invention.

Fig. 2 is a horizontal section through the contacting chamber on the line 2-2 of Fig. 1.

Fig. 3 is a cross-section through a portion of the motor blower compartment on the line 33 of Fig. 1,

Fig. 4 is a detail perspective view of the air contacting passageway.

Fig. 5 is a horizontal section through a portion of. the radial contact passageway and heater chamber.

Fig. 6 is a vertical section through a modified form of the apparatus.

Fig. 7 is a detail section on the line '!1 of Fig. 6.

Referring more in detail tothe drawings:

I designates a gas generating apparatus in-- cluding a tank or vessel 2 having a cylindrical, vertical wall 3, a bottom 4, and a crowned cover 5. Extending horizontally across the interior of the vessel, between the bottom 4 and cover 5, are spaced partitions 6 and l, forming a heating chamber 8 therebetween and respectively cooperating with the bottom 4 and cover 5 to form a lower motor and blower compartment 9 and an upper contact chamber Ill. The contact chamber Ill contains the volatile hydrocarbon, such as gasoline, as indicated at I l, and which is inserted through a filler connection l2 attached to the side of the vessel and normally closed by a plug l3. The level of the liquid in the contact chamber is shown by a sight gauge l4 that is connected with the side of the vessel and within the normal range of liquid level to be carried in the contacting chamber. 7

Located in the compartment 9 is a blower I5, having its inlet side located in registry with an air inlet opening it that is formed in the side wall 3 and covered by a suitable screen IT. The outlet I8 of the blower is connected by a duct IS with an air inlet connection 20 opening into the heater chamber 3, which in turn communicates with the contacting chamber ll! through a centrally located stand pipe 2|. The blower I5 is operated by a motor 22 that is connected therewith to drive the blower at a suitable speed for maintaining flow of a predetermined volume of air from the atmosphere through the inlet opening l6, and for discharging the air at higher pressure through the duct l9 into the heating chamber 8 and from the heating chamber through the stand pipe 2| from where it is diverted for travel through the body of contactin liquid l, as now to be described.

Extending radially from the stand pipe 2|, and resting upon the partition 6, are channel-shaped supports 23 having upper flanges 24 sloping downwardly toward the wall 3, as best shown in Fig. 1. Seated upon the flanges 24, in telescoping relation with the stand pipe 2|. is a contact baffle 25 including a flat, slightly cone-like corrugated diaphragm 26 having its base periphery terminating short of the wall 3 to provide an annular passageway 2'! therebetween, the periphery of the diaphragm having an upwardly directed annular flange or lip 28. Connected with the center of the diaphragm is a cap-like sleeve 29 located in covering relation with the stand pipe and having a closed upper end 30, the sleeve being of sufficient length and diameter relatively to the stand pipe to provide a gas passageway 3| extending across the top of the stand pipe, and a vertical, annular passageway 32, encircling the stand pipe, and communicating with the passageway 34 through an annular opening 33 in the axis of the diaphragm. The air is thus diverted from the stand pipe 2| and flows downwardly through the passageway 32 and radially through the passageway 34 in contact with the liquid carried in the contacting chamber. The air, upon contact with the liquid, is enriched by the vapors therefrom and is discharged through an outlet 35 in the apex of the cover 5.

As above pointed out, the amount of vapor picked up by the air is controlled by the temperature and humidity of air drawn into the inlet l6, and since apparatus of this character must be constructed to operate at temperatures varying from around 100 F. to a temperature of 35 F., it is impossible at these varying temperatures, to provide a gas having a constantly uniform B. t. u. content due to variation of absorption capacity of the air at different temperatures. For example, with a liquid hydrocarbon having 180 initial boiling point and a 323 end point, which is a distillate cut principally of the parafiin series of hydrocarbon compounds and falling between C'lHlS and CsHzo, or pentane and nonane with octane CsHm representing the average composition of hydrocarbon for use in the apparatus, and with the air supply adjusted so as to fully maintain saturation of the air with distillate vapors at a given temperature, lowering of the temperature results in rapid decrease in the vapor absorbing power of the air. Actual laboratory tests have shown the following results wherein the 100% column indicates results at 100% saturation. In the third column is the vaporization efficiency which could be obtained in normally good practice.

On vaporizing with, say octane, the upper limit of explosibility is on a 210 B. t. u. mixture. By

observing the 80% column it will be noted that in normally good practice the B. t. u. value is 264, which is above the upper explosive limit. At 60 F. and allowing 80% efliciency, the result is noted at 192 which is somewhat under the upper limit of explosibility but not dangerously under it. Below temperatures of 60 F. the resultant gas would be well within the range of combustibility with the result that flash-backs are liable to occur and result in a serious explosion. I therefore provide the chamber 8 with a heater here shown as an electric resistance element 36 that is supplied with a suitable current under control of a thermostatic regulator 36' so as to maintain a predetermined uniform temperature of the air discharged into the contact chamber regardless of the prevailing atmospheric temperatures. The bulb element 35" of the thermostat may be located at any convenient place in the heat zone of the generator or distribution system, but is shown in the drawings as located in the manifold connection 39 and operably connected with the switch element of the regulator controlling electric current to the heating element. The space between the partitions 8 and I is, therefore, insulated circumferentially of the heater, as indicated at 31. and the entire outer side wall 3 and cover 5 are provided with a suitable insulating cover 38 so as to reduce the influence of external temperatures upon the temperature carried within the contacting chamber. By thus maintaining a substantially uniform temperature Within the contacting chamber, gas having a constant B. t. u. value may be delivered through the outlet 35 as long as the level of the liquid remains uniformly constant. The gas upon discharge through the outlet 35 flows into a manifold connection 39 for distribution to the point of use through a pipe line 40. I also find it desirable to cover the pipe line with an insulating material, indicated at ll, so as to prevent condensation of vapor from the gas incidental to effects of the surrounding temperature. The inlet of the pipe GE! is provided with a suitable fire-stop in the form of a gauze cone, as indicated at 42, so that should any flash-back occur in the line it cannot ignite the gas mixture contained in the contact chamber I0. The out let 35 is also provided with a grill 4 3 which serves as a spray eliminator as well as a secondary firestop.

It is apparent that the liquid is gradually consumed so that the level thereof falls within the contact chamber with the result that the con tact period becomes less, and therefore pick-up of the vapor is reduced with the result that the B. t. u. content of the enriched air drops below that required to maintain the burners operating efficiently. The B. t. u. content would also drop below that required to keep the gas safely above the combustion range. I therefore provide the apparatus with means for maintaining a definite contact period of the air with the liquid regardless of the rise and fall of the liquid within the chamber ID. This is accomplished by providing a uniformly constant contact head of liquid above the passageway 34.

Supported within the contact chamber H], and having its lower end resting upon the periphery of the diaphragm 26 in inwardly spaced relation with the flange 28, is an annular wall 44 spaced from the Wall 3 to form a vertical passageway 45 through which the enriched air must pass on its way to the discharge outlet 35. The upper edge of the wall 44 forms a weir 56 over which surplus liquid overflows into the body of the liquid carried in the contact compartment. Liquid is admitted into the passageway 45 through a series of perforations 41 that is formed in the lower edge of the wall 44 in substantially horizontal.

registry with the flange 28. The flange, or 11p 28, directing the air past the perforations, causes aninducing action whereby liquidis drawn, from the chamber I above the diaphragm and moved upwardly through the passageway 45 for overflow across .the weir 4'6. Inv order to maintain the wall 44 in centered relation with the wall 2, the periphery thereof is provided with vertical spacers 41'.

The contact time of the liquid with the air is thus kept, constant as a fixed static head is maintained in the passageway 45 incidental to the inducing action of, the air. This constant circulation of the liquid from the chamber |D through ration by the air so that the B. t. u. content of the gas is as high as possible to keep it out of the explosion range and to get greatest efiiciency and capacity from the unit.

In order to maintain the pressure within the contact chamber and pipe line when the blower is out of operation, the discharge end of the stand pipe 2| is provided with a gravity valve 48 which is kept open as long as the blower is in operation, but which drops into seating relation with the end of the pipe when the blower is out of service.

The form of the invention illustrated in Fig. 6 is substantially the same as that of the preferred form with exception of the arrangement of contact passageways. In this form the cap-like sleeve 49, which covers the stand pipe 50, carries a disk-like baffle that is suspended above a horizontally arranged secondary baffle 52 which is supported above the upper partition 6 to provide a liquid passageway 53 thereunder. The bafiles 5| and 52 thus form a radial passageway 54 therebetween through which the air must travel before it can escape over the edge of the baflie 5|. Extending about the periphery of the bafile 52 is an annular ring 55 which projects above the baflle 5| and terminates in an inwardly directed annular wing 56 for diverting the air toward the axis of the contacting chamber for return flow across the top of the baffle 5|. In order to provide a constant head of liquid through which the air must move, the baflies just described are covered by a baffle 51 that is spaced therefrom by an annular flange 58 to provide a liquid passageway 59 above the wing 56, and which extends about the periphery of the ring 55. The inner periphery of the baffle 51 is connected with a cylindrical collar 60 that extends upwardly of the sleeve-like cap, in spaced relation therewith, to form a head of fixed height. In order to supply liquid to the air passageways, the flange 56 and ring 55 are provided with ports 6| and 62. The cap-like sleeve 49 carries a deflector plate 63 that is spaced above the edge 64 and projects radially to form a bafile to prevent any entrained liquid from. being carried with the gas through the outlet 35. The stand pipe, cap-like sleeve and cylindrical collar 60 are spaced apart by suitable spacers 65 and 66, as best shown in. Fig. 7.

The operation of the apparatus constructed and assembled as illustrated in Figs. 1 to 5 inclusive is as follows:

The plug I3 is removed and a suitable liquid hydrocarbon, such as gasoline, is poured into the contacting chamber-through the inlet connection I2 until the level in the contacting chamber sub.- stantially reaches the top of the fill connection. The plug I3 is then replacedand the motor 22 and heater 35 are put in operation by connecting them with a suitable current supply shown in diagram Fig. 1. Air is then drawn by the blower through the inlet l6 and discharged at higher: pressure through the pipe l9 and connection into the heating chamber 8 where the air is brought to the desired temperature as set by the thermostat, for example the minimum tempera.- ture of 70 F. The heater also raises the tem. perature of the liquid to substantially the air, temperature. The air discharges from the heating chamber through the stand pipe 2| and lifts the check valve 48 for flow through the passageways SI and 32 in the sleeve-like cap. The air then moves downwardly through the liquid which rises within the sleeve-like cap through the liquid contained in the passageway 34 where it moves radially in scrubbing relation with the corrugations on the under side of the diaphragm 26 toward the annular passageway 21 and over the lip through the liquid carried in the annular passageway 45. This movement of the air lifts the liquid in the passageway 45 in the form of bubbles and effects inducing action thereof from the contacting chamber through the apertures 41 so that as the liquid is displaced within the passageway 45 it is continually replenished from the main supply. The air is thus thoroughly contacted with the liquid and is discharged from the top of the passageway into the space that is carried above the liquid in the contacting chamber. The surplus liquid flowing over the top of the weir 46 falls back into the body of liquid and the enrichened air discharges through the grill 43 into the manifold 39, and through the cone 42 into the pipe 40 where it flows to the burner.

With the apparatus as above described, the air is kept moving through the same hydrostatic head of liquid so that with a uniform temperature, as controlled by the heater, a uniformly enriched mixture is maintained for flow to the burner. By proportioning the amount of air and controlling the temperature the B. t. u. value may be kept near the saturation point so that it is well above combustible range, and there is little or no possibility of flash-back through the pipe line 40 for the reason that the gas mixture is too rich to produce an explosion.

The form of the invention illustrated in Fig. 6 operates in substantially the same manner as in the preferred form. In this form of the inven tion the air, after being heated, moves downwardly in the passageway surrounding the stand pipe 50, through the passageway 54 over the edge of the baffle 5| and inwardly through the passageway 56 for flow up through the passageway formed within the collar 60, the latter passageway being soproportioned that the air flow induces movement of liquid through the ports BI and 62 to retain the air passages full of liquid. The liquid being carried by the air overflows the edge 64 and the air enriched by the vapors picked up through contact with the liquid is discharged around the periphery of the deflector 65 to accumulate in the space above the level of liquid in the contacting chamber. The enriched air or gas is drawn off through the grill 43 in the same manner as described in the first form of the invention.

From the foregoing it is obvious that I have provided a method of forming a combustible gas by enriching air with a hydrocarbon vapor which is eflicient in operation and wherein the B. t. u. value of the gas may be kept at a minimum Well above the explosion range.

What I claim and desire to secure by Letters Patent is:

1. The method of preparing and maintaining a normally non-explosive air and vapor mixture including, contacting air and. a volatile petroleum hydrocarbon liquid to eiTect absorption by the air of hydrocarbon vapors in quantity to form a mixture having a B. t. u. value within a safely non-explosive range at the upper explosive limit, applying heat in the zone of contact to maintain the absorbing power of the air necessary in effecting said B. t, u. value upon drop in atmospheric temperature, controlling said heat to maintain a substantially uniform temperature necessary to maintain said B. t. u. value of the mixture, and storing said mixture and conveying said mixture Without material loss of heat to a point of use.

2. The method of preparing and maintaining a normally non-explosive air and vapor mixture including, confining a body of volatile petroleum hydrocarbon liquid, passing air in sub-surface flow through said liquid in a plurality of superimposed levels to provide contact time for the air to absorb sufficient hydrocarbon vapors to form a mixture having a B. t. u. value within a safely non-explosive range at the upper explosive limit, applying heat in the zone of contact to maintain the absorbing power of the air necessary in efiecting said B. t. u. value upon drop in atmospheric temperature, controlling said heat to maintain uniform temperature of the mixture necessary to retain said B. t. u. value, and storing and conveying said mixture to a point of use Without material loss of heat.

ALFRED J. DIESCHER.

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