US2356838A - Gaseous fuel burner - Google Patents

Description

Aug. 29, 1944. J. E. FARRELL 2,356,838

GASEOUS FUEL BURNER 3 Sheets-Sheet 1 Filed April 2, 1942 Aug. 29, 1944. E, FARRELL I GASEOUS FUEL BURNER Fild April 2, 1942 s Sheets-Sheet 2 A'Ar Patented Aug. 29, 1944 UNITED GASEOUS FUEL BURNER Joseph E. Farrell, Toms River, N. J., assignor to National Engineering Foundation, Inc., Washington, D. C., a corporation of Delaware Application April 2, 1942, Serial No. 437,437

8 Claims.

ticularly lend themselves to established manufacturing practices, thereby facilitating the manufacture and assembly of the device, while at the same time including a new arrangement anddisposition of these parts which has proved highly satisfactory in service.

With the above and other objects of the in-' vention in view which will more readily appear as the nature of the invention is better understood, the same consists in the novel combination and arrangement of parts hereinafter more fully described, illustrated and claimed.

A preferred and practical embodiment ofthe invention is shown in the drawings, wherein:

Fig. 1 is a vertical sectional view, isometrically projected, of the preferred embodiment of the invention with a portion of the housing of the flame initiator broken away to better show the passage which causes air to sweep downwardly on the initial fuel distributing head.

Fig. 2 is a horizontal cross-sectional view, taken on the line 2-2 of Fig. 1.

Fig. 3 is a horizontal cross-sectional View, taken on the line 3-3 of Fig. 1.

Fig. 4 is a top plan view of the housing of the flame initiator unit.

Fig. 5 is a vertical sectional view of a modified form of construction, with a portion of the flame initiator housing broken away as described in connection with Fig. 1.

Fig. 6 is a horizontal sectional view taken on the line 6-6 of Fig. 5.

Similar reference characters designate corresponding parts throughout the several figures of the drawings.

-According to the embodiment shown in Fig. 1, the invention includes in its organization a casing A having combustion ring B at the upper portion thereof, together with a flame initiator unit, designated generally as C, and arranged within the mixing chamber AI of the casing beneath a gas producing unit, designated generally as D.

The casing A is provided at its bottom with'an provided with 'an'outwardly'extending shelf 4' formed substantially at its outer rim with an upstanding flange -5. This flange cooperates with the laterally spaced upstanding flange 6 of a cover plate I which overlies themixirig' cham ber AI to provide a channel which forms the aforesaid annular combustion ring 13; Between the under side of the cover plate I and the shelf 4 there are provided a plurality of flat annular grid members 8 arranged in vertically spaced relation, which serve to distribute air and gas from the mixing chamber Al 'to the combustion ring B, and also prevent backfire.

The flame initiator unit C preferably includes a cup-like housing 9, which is provided at diametrically opposite points with offset ribs or bosses I0 extending vertically throughout the side wall thereof. Also, the housing is provided at the location of theribs I0 and at points relative thereto, with the offset shoulders I I, which, as presently appear, cooperate with the sleeve I2 of the gas producing unit. At this point it may be noted that the purpose of providing the ribs ID in the side wall of the housing 9 is to permit the main inner sleeve I2 of the gas producing unit to be'spaced from the outer wall of the housing, thereby to provide an air passage -I3 which will later be described in connection with the gas producing unit.

The bottom well I4 of the housing '9 is preferably of frusto-conical formation and has the opening I5 thereof disposed to receive air from the inlet I. As a matter of fact air issuing from the inlet opening I of the casing will pass through the opening I5, and, also, a portion of the air will be deflected by the conical wall I4 outwardly toward the sides of the casing I.

Referring further to the flame initiator C, it will be observed that the inner side of the wall I4 is provided with an upstanding collar I fi intended to receive aforaminous air diffusing disc IT. This disc is provided with a central nipple portion I8 which is threaded into theglancl nut I9 carried bythe pipe 20. The said pipe-'20 has its lower end 2| connected-with the boss 22 of a suitable fitting 23 formed in theair' inlet connection or elbow-2. As will also be observed from Fig. 1, thelower end of the pipe 20 communicates with the bypass 23 of the initial fuel supply means which is controlled by the valve 24. This valve is preferably of the electromagnetically controlled type intended to operate under the influence of the electromagnet 25 connected with suitable thermostatic controls in the room or other space to be heated.

The stem on which the valve 24 is mounted is also provided with a valve head 26 for controlling the supply of liquid fuel to the branch line 21, and valves 24 and 26 are both intended to control the supply of fuel from a tank or other source of supply connected with the fitting 28. The valve arrangement is such that when the thermostat registers a demand for heat, the valve 24 is opened and the valve 26 is closed, thereby permitting initial fuel to be supplied through the bypass 23 to the lower end of the pipe.20. On the other hand, after a sufficient quantity of initial fuel has been supplied and the electromagnet 25 is deenergized, the valve 24 will drop to its seat and the valve 26 will be opened, thereby to permit liquid fuel to flow through the branch 21 into the main feed pipe 29 which supplies the retort R of the gas producing unit, as will hereinafter appear. It will be apparent from Fig. 1 that the pipes 20 and 29 are coaxially related so thatthe initial fuel supply is conveyed upwardly to the fuel distributing head 30 of the flame ini tiator unit between the inner wall of the pipe 20 and the outer wall of the pipe 29.

The upper end of the pipe 20 is suitably fitted to the bottom wall of the initial fuel distributing head 30, which is preferably of cup-like formation and has its outer edge formed as the frustum of a cone to provide a fuel cascading surface 3|, The top of the head 2|] is fitted with a cover plate 32 supported by the hollow rivets 33 in such a way that a space is provided between the outer edge of the cover and the upper edge of the cascading surface 3|, thereby to permit initial liquid fuel to spill over a relatively large area to facilitate ignition by the spark plugs or equivalent igniting devices 34. These devices may be of any conventional type and are preferably mounted in the side wall or body of the casing l with their sparking terminals extending through the housing 9 and arranged in relatively close proximity to the bottom edge of the cascading surface 3|. It will, of course, be a'pparent that the fuel distributing head 39 is spaced from the adjacent side of the air diffusing disc I! so that air jets issuing from the disc will supply ample oxygen for sustaining combustion of the initial flame for heating the retort R of the gas producing unit.

Referring now more especially to the gas producing unit D, which includes the main inner sleeve [2 previously referred to, it will be observed from Fig. 1 that the inner face of the inner sleeve I2 is provided with a deflector l2a connected with the inner face of the sleeve by an angularly disposed curved portion I217. The object of this arrangement is to conduct air from passage l3 downwardly into the flame initiating unit so that any raw liquid fuel, dropping from the lower edge of the cascade surface 3| into the recess formed between the bottom wall l4 of the housing and the collar [6, will be supplied with sufficient oxygen to cause its consumption during and after the flame initiator unit has performed its required function of supplying sufficient heat to gasify liquid fuel in the retort R.

The retort R preferably includes a hollow base channel 35 which is connected by the branch pipes 36 with the liquid fuel supply pipe 29. The upper portion of the outer wall of the channel is provided with openings 35a which register with the hollow spokes 31 of a cap 38 which fits over the base channel. The said cap 38, therefore, not only closes the channel but also carries the hollow spokes 3! and is outwardly flanged at 39 and 40 respectively to engage the sleeve I2 and to support an outer sleeve 4| in spaced relation to the main sleeve, thereby to provide an annular space or conduit 42 which is in communication with each of the hollow spokes 31. The lower end of the outer sleeve 4| engages with a cover ring 43 which, together with the cover plate 1, forms a gas accumulating well 44. At suitable spaced intervals the cover plate I is provided with aspirating tubes 45, whose upper ends project into the well 44 and whose lower ends are provided with the inverted cups 46 disposed in the ascending airstream of the mixing chamber Al. The effect of air passing over and about the face of the cups 46 is to form a vacuum at the rear thereof which will pull the relatively inert gas through the tubes from the chamber 44 and through the openings in the bottom of the tube adjacent the cups- The channel 35 of the retort R is also provided with aspirating tubes 41 whose upper ends project into the channel to substantially the level of the openings 35a, thereby to define the depth of liquid fuel held in the ring 35 and also receive a portion of the gas generated in the retort. The said aspirating tubes 41 are also fitted at their lower ends with the cup-like elements 48, which have the effect of producing a vacuum at their downstream faces under the influence of the air blast passing upwardly from the zone of the flame initiator unit, thereby to pull gas from the retort and provide in effect a plurality of torches during burner operation which will supply gasifying heat to the retort, in addition, of course, to the heat imparted to the retort by combustion sustained at the main combustion ring B,

The operation of the construction shown in Figs. 1 to 4 inclusive is substantially as follows. When the thermostat calls for heat, the electromagnet 25 is energized, thereby lifting the valve 24 from its seat and placing the bypass 23 in communication with the fitting 2B of the oil supply" pipe. Oil or liquid fuel will be conveyed by the pipe 20 to the distributing head'30 where it will cascade over the lsurface 3| and become ignited by the operation of the sparkingdevices 34 which are electrically energized simultaneously with the electromagnet 25. The initial flame thus produced will be, oxidized by air coming in through the inlet l, which makes its way through the opening I5 into the housing 9 of the flame initiator unit, and combustion will also be assisted by down-draft air furnished through space l3 and deflector 12a.

The flame initiator unit thus heats the retort Rof the gas producing unit, which always contains a residual quantity of oil.- As this, oil becomes gasified, the continued operation of the air blast device supplying air to the mixing chamber Al and to the interior of the flame initiator housing, will cause the inert gas formed in the retort to be aspirated from space 42 and well 44through the,tubes 45 and also from the retort through tubes 41. The gas issuingfrom the tubes 41 will be ignited from the flame of the initiator unit and the flame thus propagated will supply heat-to the retort. Likewise, gas aspirated through the tubes 45 into the mixing chamber AI will be mixed with thus connecting the pipe 29 with the-oil supply connection 28. As the air blast supplying means continues to furnish air tothe interior of the casing, sustained combustion will take place due to the mixing of gas and air in the mixing chamber, as well as in the space provided between the retort and the flame initiator unit.

Fig of the drawings illustrates a modification of the invention wherein all of the essential fea- 7 tures and characteristics in connection with Fig. l are preserved, the only exception being in connection with the means for aspirating gas from the retort. In Fig. 5 the casing, combustion ring, flame initiator unit, cover plate and retort of the gas producing unit, are the same as described in connection with Fig. l, and therefore are designated by similar references. I In this construction, however, the main inner sleeve l2 of the gas producing unit and the outer spaced sleeve Ma, which provide the annular gas conducting space 42a, terminate within the upper end of the'mixing chamber Al, the lower ends of the sleeves and the outlet of the space 42a being masked by an annular offset flange or lip 50. This flange or lip is spaced below the bottom edge of the sleeves so that as the ascending airstream passes the peripheral edge of the flange 50, a vacuum will be created behind the flange, .thereby to pull or aspirate gas required for sustained combustion at the combustion ring B.

In this form of the invention the operation will be the same as that described in connection with Fig. 1, except that instead of the major portion of the gas for sustained combustion being aspirated through the tubes 45 in Fig. 1, it will be aspirated from the space 42a directly into the upper portion of the mixing chamberAl before it passes into the combustion ring B.

From the foregoing it will be apparent that both forms of the invention provide means for initially heating liquid fuel trapped in a retort so as to produce a gas in the absence of air which may not only be burned when thereafter mixed with air for heating purposes, but will also produce sustained gasification of liquid fuel throughout the required period of burner operation. The constructions described produce a dry gas which, because of the fact that it is produced from low grade fuel oils, has no power of expansion. Therefore, it becomes necessary to pull or aspirate the gas from the retort into the airstream with which it is admixed to provide a proper burnable or combustible mixture. The arrangement described in both forms of the invention provides for superheating the gas in such a way that all residual moisture is driven off in the process of gasification, thereby producing a combustible mixture with the air which produces a flame of much higher temperature than wet gaseous mixtures, that is mixtures wherein the liquid fuel is atomized into the airstream.

I claim:

1. In a fuel burner for converting liquid fuel into gas, the combination with a casing having an air inlet and formed to provide a mixing chamber, and a main combustion ring at the outer edge of the casing; of a flame initiator unit within the casing above the inlet, said unit comprising a housing having an opening at its bottom and exposed to the airstream from said inlet, an air diffusing disc above said opening, a liquid fuel supplying head above the disc and including a fuel cascading face, igniter means adjacent said face; a gas producing unit including a retort'supported in the airstream above the flame initiator, means for aspirating the gaseous fuel from the retort into the mixing chamber and into the airstream below said retort, means for supplying'air tothe casing, and means for conveying liquid fuel to the supplying head and the retort.

-2. In a fuel burner for converting liquid fuel into gas, the combination with a casing and a cover plate providing a mixing chamber, said casing having an air inlet and a main outer combustion ring; of a flame initiator unit in the mixing chamber and comprising a housing provided with lateral offset ribs and having a bottom wall in the form of a truncated cone to provide an opening for admitting air to the unit and also deflecting air towards said combustion ring, a foraminous air diffusing discwithin the housing inwardly of the opening, a liquid fuel distributing head also in the housing inwardly ofthe disc, igniter means adjacent the fuel distributing head; a gas producing unit above the flame initiator unit and including, a sleeve cooperating with the ribs of the housing, a deflector carried by the sleeve to provide an air space betweenthe mixing chamher and the housing, and a retort supported in the upper end of the sleeve to locate it in'the airstream above the flame initiator unit; means for aspirating the gas from the retort into the mixing chamber of the casing and within the sleeve of the gas producing unit, means for supplying air to the casing, and means for supplying liquid fuel to the said fuel distributing head and to the retort.

3. In a fuel burner for converting liquid fuel into gas, the combination with a casing providing a mixing chamber and having a forced air inlet; of a main combustion ring at the upper perimeter of the casing, said ring comprising a shelf and an upstandin peripheral wall, a horizontally disposed grid supported in spaced relation to said shelf, and annular cover plate resting on and spaced from said grid, said plate having a central opening and a marginal flange, the

latter being spaced inwardly of the peripheral wall of the casing to provide an annular flame propagating channel; a flame initiator unit in the casing, ignition means therefor; a gas producing unit arranged within the central opening of the cover plate and including a retort disposed above the flame initiator and having conduit means whose outlet end communicates with the mixing chamber above the flame initiator, means for aspiratin gas from the outlet of said conduit, means for aspirating gas from the retort, and means for supplying liquid fuel to the flame initiator and retort.

4. In a fuel burner for converting liquid fuel into gas, the combination including a casing providing a mixing chamber and having a forced air inlet, a shelf and an upstanding peripheral wall at the upper edge of the casing, a plurality of horizontally disposed vertically spaced grids supported on said shelf, an annular cover plate resting on said grids, said plate having a central opening and an upstanding marginal flange, the latter being spaced inwardly of the peripheral wall of the casing to provide a combustion ring having an annular flame propagating channel, a cover ring cooperating with the cover plate to provide a gas accumulating well; a flame initiator unit in the casing, ignition means therefor; a

gas producing unit arranged within the central opening of the cover plate and including a retort disposed above the flame initiator and havin conduit means communicating with the mixing chamber of the casing and with the space above the flame initiator, means for aspirating gas from the retort into the airstream below the retort, other means for aspirating gas from said weil into the mixing chamber, and means for supplying liquid fuel to the flame initiator and retort.

5. In a fuel burner for converting liquid fuel into gas, the combination with a casing formed to provide a mixing chamber and having an air inlet and a main combustion ring; of a flame initiator unit including a housing opening at its bottom end into the mixing chamber, an initial fuel supply head and an air difiusing disc in the housing, ignition means adjacent the said head; a gas producing unit comprising a pair of spaced sleeves, one of which cooperates with said housing and including a retort in communication with the space between said sleeves, means forming a gas accumulating well in communication with said retort through the spaced sleeves, said last named means lying above the mixing chamber of the casing and within the combustion ring, means for aspirating gas from said well into the mixing chamber, means for aspirating gas from the retort into the said sleeve, means for supplying liquid fuel to the said head, and means for supplyin liquid fuel to said retort.

6. In a fuel burner for converting liquid fuel into gas, the combination with a casing formed to provide a mixing chamber and having an air inlet and a main combustion ring; of a flame initiator unit including a housing opening at its bottom end into the mixing chamber, an initial fuel supply head and an air diffusing disc in the housing, ignition means adjacent the said head; a gas producing unit comprising a, pair of spaced inner and outer sleeves, a retort supported by the inner sleeve and in communication with the space between said inner and outer sleeves, said inner sleeve being spaced from the housing to provide an air passage, a deflector carried by the inner face of the inner sleeve and extending over and parallel to the inner side of the housin to direct air from the mixing chamber downwardly and about the flame initiator unit; means forming a gas accumulating well in communication with said retort through the spaced sleeves, said last named means lying above the mixing chamber, means for aspirating gas from the retort through the space defined by said sleeves; and from said well into the mixing chamber, means for supplying liquid fuel to the said head, and means for supplying liquid fuel to said retort.

7. In a fuel burner for converting liquid fuel into gas, the combination with a casing providing a mixing chamber and having an air inlet axially of its bottom and extending upwardly and outwardly to form a shelf and a peripheral wall; of co-axial outer and inner fuel supply pipes projectin through said air inlet for supplying liquid fuel for initial and sustained operation; a flame initiator unit supported on said outer pipe and including a housing having a bottom air intake opening, a foraminous air diffusing disc inwardly of said opening, a fuel supply head communicating with the outer pipe and having a fuel outlet, igniter means cooperating with said head; a gas producing unit including an annular sleeve having its lower portion fitting over the upper part of said housing in spaced relation to the outer wall thereof, a deflector wall carried by the inner side of the sleeve and disposed in spaced relation to the inner wall of the said housing to form a passage for directing air from the mixin chamber toward the flame initiator unit, a retort communicating with the inner fuel pipe, aspirating tubes having their inlet ends disposed in the gas chamber of the retort and having their discharge ends disposed in the airstream below the retort, a combustion ring formed at the periphery of the said shelf, and means forconducting and aspirating gas from the retort to the mixing chamber and combustion ring.

8. In a fuel burner for converting liquid fuel into gas, a casing having an air inlet, a cover plate for the casing defining therewith a mixing chamber, means formin a main outer combustion ring at the outer edge of the casing, a flame initiator unit in the mixing chamber and comprising a housing having a bottom opening disposed in the air stream entering said inlet, air and liquid fuel distributing elements arranged in axially spaced relation above said bottom opening, igniter means adjacent the fuel distributing element, a gas producing unit disposed centrally of said cover plate above the flame initiator unit and comprising asleeve and a deflector which are disposed in concentric spaced relation and connected by a wall disposed substantially at right angles to the vertical planes of the sleeve and deflector, said sleeve and deflector being dis-l posed astride the upper end of said housing to provide air circulating space between the mixing chamber and the housing, a retort carried by the upper end of the sleeve and located in the air stream above the flame initiator unit, separate means respectively for aspirating gas from the retort into the mixing chamber of the casing and into the sleeve below the retort, and means for supplying liquid fuel to the said fuel distributing element and to the retort.

JOSEPH E. FARRELL.

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