US2149770A - Liquid fuel furnace - Google Patents

Description

March 7, 1939.. s, H HOOK 2,149,770 LIQUID FUEL FURNACE: I

Filed Feb. '7, 1938` 2 Sheets-Sheet O v(DOOOOOOO Patented Mar. 7, 1939 LIQUID FUEL FURNACE Sydney Harold Hook, Gardiner. victoria,l Australia Application February 7, 1938, Serial No. 189,265 In Australia April 22, 1936 '7r Claims.

This invention relates to liquid fuel furnacesV to provide an improved liquid fuel furnace of thel l type indicated which embodies improved means for dividing the film of fuel flowing over the burner plate and the air draft passing thereover, into a large number of relatively small streams thereby ensuring an intimate mixing of the air and fuel vapour and a material improvement in the general efficiency of this type of furnace.

Another object of the invention is to provide in a liquid fuel furnace of the type referred to, improved draft control means whereby one or 20; more'induced airdrafts is or are directed downwardly towards the burner plate and caused to pass over the inner end portion thereof in close proximity to the film of liquid fuel owing there- A over; whereby mixing of the air and fuel vapour 25' and combustion of the resultant gases is greatly improved while the possibility of the ignited gases blowing back towards the front of the furnace, is reduced tofa minimum.

Referring to the drawings which form part of I 3U* this specification:-

Figure 1 is a longitudinal section of an improved liquid fuel furnace in accordance with one embodiment of the present invention.

v Figure 2 is a part-sectional plan View taken on the line II-II of Figure 1. Figure 3 is a fragmentary section onan enlarged scale of the inner edge portion of a burner plate in accordance with a modification of the invention.

` Figure 4 is a fragmentary plan view of the burner plate seen in Figure 3.

Figure 5 is a front view of the furnace seen in Figure 1, parts being broken away for convenience of illustration. Y

Figure 6 is a cross-section taken on the line VIV- VI of Figure 1.

`Figure 7 is a fragmentary plan View on an enlarged scale showing means for delivering a plurality of relatively small streamsY of water onthe burner plate.

Figure Sis a fragmentary longitudinal section of the lower end portion of a burner plate in accordance with a' further modification of the in.-

,65 Yention. v Y

Figure 9 is a cross-section taken on the line IX-IX of Figure 8.

In accordance with one practical embodiment of the invention as illustrated in Figures 1, 2, 5 and 6 of theA drawings, the improved liquid fuel furnace includes a burner plate 2 mounted upon a supporting frame 3 and inclined downwardly from the front towards the rear so as to cause oil or like fuel which is deliver-ed onto the upper surface ofthe burner plate to gravitate in a relativelythin lmtowards the inner edge thereof, as Ahereinafterdescribed.

This burner plate 2 preferably includes a main fiat section 4 provided at its inner end with one or more stepped portions E which are located at a lower level than that of the main section. As illustrated in Figure 1 of. the drawings, two of these stepped portions may be employed and the upper surface 'l of each stepped portion is preferably inclined in the opposite direction to that of the mainV section 4 of the burner plate with a view to trapping the residue of the liquid fuel owing over the lower edge of the main section of the burner plate until the fuel is finally consumed.

. Alternatively, if two of such stepped portions areemployed, the upper one 6a may be inclined in the same direction as that of the main section 4 of lthe burner plate, while the lower stepped portion 6b is inclined in the opposite direction as seen more clearly in Figure 3 of the drawings.

Each stepped portion 6 of the burner plate also includes an upright wall 8 provided with a plurality of longitudinally spaced apertures 9 formed therethrough in order that a draft of air may be induced to pass through the fuel falling downwardly lacross said apertures. Provision is also preferably made for directing a draft of air beneath the lowermost stepped portion of the burner vplate and for this purpose the latter stepped portion may be provided with a plurality of depending lugs II adapted to rest upon a tray or-bottom wall I2 of the furnace, thus forming air passages between said lugs.

Y .Liquid fuel is fed by gravity, for example from ajsuitable container (not shown) through one orimoredelivery pipes I3 into a well or recess I4 formed in the upper surface of the main section 4 of the burner plate. This well may be circular, elongated or any other suitable shape in plan and one or more of such wells may be employed depending upon` the width of the burner plate.V Eachsuch well I4 communicates with a series of open-ended channels I6 which are formed in the uppersurface .of the burner plate and radiate towards the lower inner edge thereof. Y These channels may progressively decrease in depth as they approach the inner edge of the burner plate. Each of these channels may also increase in width as it approaches its lower end, so that the liquid fuel is spread over the burner plate and caused to flow towards the inner end thereof in a relatively thin film.

The main section 4 of the burner plate is provided adjacent the lower or inner end thereof with means for dividing the lm of oil or like fuel passing over this section of the burner plate into a large number of relatively small streams. For this purpose, the burner plate is provided with a series of upstanding and laterally spaced projections i8 which are preferably arranged in one or more rows extending completely across the burner plate adjacent to the rear or inner edge of the main section 4 thereof. Each such projection is of substantially pear-shape in plan, the front edge portion of the projection being relatively wider than the rear edge thereof. For eX- ample, the front edge I9 may be of substantially convex curvature and merge into side walls 2l which taper into a relatively thin tail 22 at the rear of the projection. Such tapered projections have proved to be particularly ecient in effectively dividing the oil or like fuel into a num ber of small streams. Y

If more than one row of such spaced projections I8 are employed, the projections in adjacent rows are preferably staggered in such a manner that the tails 22 of the projections in the front row are located in alignment with the spaces between the projections in the rear row as seen more clearly in Figure 6 of the drawings.

A continuous or unbroken rib 23 preferably eX- tends across the burner plate Ybetween the series of upstanding projections I8 and the inner edge of the main plate section Il. 'I'his rib is adapted to function as a dam for retarding the escape of the liquid fuel over the inner edge of the main plate section.

If desired, the inner edge portion of the main section of the burner plate may overhang the upright wall 8 of the associated stepped portion as at 26 so as to induce the liquid fuel to fall freely from the outer edge of such overhanging portion instead of creeping down the rear face of the upright wall. If more than. one stepped portion 6 is employed, the rear edge of the uppermost stepped portion may overhang the upright wall 8 of the next stepped portion as at 21.

In combination with the foregoing, means is provided for inducing one or more air drafts to pass downwardly towards and over the upper surface of the main section of the burner plate in close proximity to the liquid fuel flowing thereover. For this purpose, one or more hoods is or are mounted above the burner plate and one of these hoods 3l communicates with one or more inlet openings 32 in the supporting frame 3. These inlet openings may be arranged one above the other as shown and each of these openings is tted with an adjustable closure for the purpose of Varying the effective area thereof in accordance with requirements. Such closures preferably consistof hinged doors 33 as seen more clearly in Figure 1 of the drawings. These doors are provided with handles 34 and retaining means for holding them in the desired positions.

The hood or deflector 3l extends downwardly and rearwardly across the main section 4 of the burner plate and the lower or rear edge 36 of this hood is, in the embodiment illustrated in Figure 1, located in close proximity tothe upstanding projections I8 thus forming a restricted discharge opening which is interrupted by the series of projections. The latter are thus adapted to perform the additional function of baffling the air drafts. This hood 3l is also preferably provided with a series of apertures 3l adjacent to the top thereof in order to by-pass part of the air draft and thus obviate the formation of soot upon the rear surface of the hood. Another series of apertures 38 may also be formed in the supporting frame 3 immediately above the hood 3| for a similar purpose.

The position of the lower edge 36 of the hood 3l in relation to the series of upstanding projections IB may vary in order to increase or reduce the effective area of the discharge opening for the air draft in accordance with requirements. For example, the velocity of the air drafts may be reduced by increasing the height of the discharge opening or by positioning the lower edge 33 of the hood either forwardly Aor rearwardly of said projections.

In View of the fact that the liquid fuel and the combustible gases are intended to be ignited at the rear of the series of upstanding projections I8 on the burner plate, it is preferred to locate the lower edge 36 of the hood in relatively close proximity to the top of the projections I8 as shown, in order to minimize the possibility of the ignited gases being blown back under the hood and thus igniting the fuel on the burner plate in front of the projections.

Should it be desired to still further increase the air draft, an auxiliary hood 39 may be positioned at the rear of the hood 3| and communicates at its upper end with another aperture in the frame 3 fitted with an adjustable closure. This auxiliary hood extends downwardly over the stepped portions 6 of the burner plate 2 as indieated for example in Figure l and. thus functions to direct the ignited gases downwardly towards the inner end portion of the burner plate thus increasing the temperature of the latter and tending to ensure complete combustion of the gaseous fuel.

The interior of the hood is preferably divided by one or more partitions or deectors 4I in order to direct the air draft downwardly towards different areas of the burner plate. In the embcdiment illustrated in Figure I of the drawings, a vfunnel 42 is preferably provided at the front of the burner plate in order to direct a draft of air straight across the latter towards the series of projections I8 in close proximity to the surface of the fuel flowing over the burner plate. This funnel is preferably open-ended and devoid of any adjustable closure. f

As Vpreviously mentioned, it is also desirable to cause an air draft to pass through the apertures 3 in the stepped portions 6 of the burner plate and also beneath the lowerrnost stepped portion. An air passage may be formed between the bottom ofthe burner plate, the tray i2 at the bottom of the furnace-and walls 46 upstanding at the top of the burner plate 2 and associated hood or hoods 3| as indicated in Figure 1.

In order to still further improve the caloric value of the furnace gases a relatively small quantity of water may be fed onto the burner plate. This water rapidly vaporizes upon reaching the hot burner plate and the constituent gases of the water are entrained in the air draft and mixed with the combustible gaseous mixture within the furnace. This water may be delivered to the burner plate 2 at several spaced points in relatively small streams. For this purpose, a distribution cup I may be provided for receiving water from a main water supply pipe 52 and this cup communicates with a series of spaced delivery pipes 53 extending downwardly towards the surface of the burner plate. The cup is provided with a plurality of internal baffles 54 adapted to split the stream of water received from the main supply pipe into a series of small streams which are directed to the respective delivery pipes. Or if desired, the water may be introduced into the delivery pipe I3 for the liquid fuel and discharged therewith onto the burner plate.

According to a modification as illustrated in Figures 3 and 4 of the drawings, a single row of upstanding spaced projections I8 on the burner plate is provided. This row of projections is positioned between the rear edge of the burner plate which is serrated as at 56 and a rib 51 which extends transversely of th'e burner plate in advance of such projections and is divided at klongitudinally spaced points so as to form openings 58 through which the liquid fuel is permitted to pass to the row of projections. This rib 51 also functions as a dam so as to retard the escape of the fuel over the lower end of the burner plate, thus retaining it as long as possible upon that part of the plate which is at the highest temperature and facilitating the vaporization of the fuel.

According to a still further modification as illustrated in Figures 8 and 9, the upstanding projections upon the upper surface of the burner plate 2 form part of a plurality of plates 6I which are spaced apart by supporting bars 62 and extend transversely of the burner plate. Each of these plates is provided with a series of longitudinally spaced apertures 63 forming projections Ia therebetween. As seen in Figure 9, each of these projections is tapered downwardly towards its lower end so as to divide the oil or like fuel flowing across the burner plate into relatively small streams. The projections in the associated plates are staggered in order to'improve the division of the fuel as aforesaid.

If desired, a burner 66 adapted to be supplied with oil or like fuel for example, from the aforesaid liquid fuel container, may be positioned beneath the burner plate 2 in order to increase the temperature thereof and thus facilitate vaporization of the liquid fuel.

In use, oil or like fuel is fed onto the burner plate 2 and caused to flow downwardly thereover in the form of a relatively` thin film until it strikes the series of upstanding projections I8 which divide the fuel into a large number of relatively small streams. The fuel is ignited at the rear of the projections I8 in any suitable manner such as by employing a wad of inflammable cotton waste or the like. The air drafts passing through the furnace both above and below the burner plate 2 may be readily controlled simply by adjusting the aforesaid closures 33, 4l associated with the air inlet apertures in the supporting frame 3. After the burner plate has been heated to a suitable temperature, the water may be supplied to the burner plate as aforesaid and the air draft increased in accordance with requirements. It is to be understood that various alterations, modifications and/or additions may be introduced in the foregoing construction and arrangement of parts without departing from thescope of the invention as defined by the appended claims.

Having now described my invention what I claim as new and desire to secure by Letters Patent isr-- 1. A liquid fuel furnace comprising an inclined burner plate adapted to be heated and provided upon its upper surface with a plurality of upstanding spaced projections, a plurality of deflectors arranged over the burner plate in spaced `relation relative to the flow direction of the fuel on the plate for causing a plurality of air drafts to be directed against different areas on the top of the burner plate of which one deflector terminates in close proximity to the projections to create a restricted passage for the air draft located adjacent to said projections whereby the liquid fuel and the air draft are forced to pass between said projections and are thus divided into 'a number of relatively small streams which facilitates vaporization of the fuel and mixing of the air draft and fuel vapour.V

2. A liquid fuel furnace according to claim 1, 1n which the burner plate includes a relatively fiat section and said upstanding projections being arranged in at least one row adjacent to the lower or rear edge of said flat section, and in which each projection has in plan a convex front edge merging into converging side walls which terminate at the rear in a relatively thin tail.

3. A liquid fuel furnace comprising an inclined burner plate adapted to be heated and provided upon its'upper surface with a plurality of upstandingspaced projections, means providing a restricted passage or outlet located adjacent to said projections comprising at least one hood positioned above said burner plate and extending downwarly and rearwardly thereover, said hood being provided with at leat one air inlet opening through which an induced air draft is admitted to said hood which is adapted to direct said air draft downwardly towards the burner plate and over the top thereof in close proximity thereto before passing through said restricted outlet whereby liquid fuel and the air draft are forced to pass between said projections and are thus divided into a number of relatively small streams which facilitates vaporization of the fuel and mixing of the air draft and fuel vapour, and at least one internal partitionfor dividing the air draft passing beneath said hood into a number of separate air streams and directing such air streams downwardly towards different areas of the burner plate.

4. A liquid fuel furnace according to claim 3, in which an air inlet funnel is provided below the level of the inlet to said hood and is adapted to direct a draft of air straight across the burner plate in close proximity to the upper surface thereof, and in which adjustable closures are provided for the inlet openings associated with said hood to vary the effective area thereof.

5. A device according to claim l, in which means are provided for discharging relatively small streams of water ontothe heated burner plate in advance of said restricted passage, said water supply means including a series of delivery pipes, the lower ends of which are laterally spaced above said burner plate and said delivery pipes communicating at their upper ends with a cup adapted to receive the water and having means for dividing the water into a number of streams which pass to the respective delivery pipes.

6. A device according to claim 1, in which the burner plate is provided With a stepped portion at the lower end of the plate, the upper surface of said stepped portion being inclined in the opposite direction to that of the main section of the burner plate and said main section being provided with an extension overhanging an upright wall of the stepped portion.

7. A device according to claim l, in which the burner plate is provided with a stepped portion at the lower end of the plate, the upper surface of said stepped portion being inclined in the opposite direction to that of the main section of the burner plate and said main section being provided with an extension overhanging an upwith a serrated edge.

SYDNEY HAROLD HOOK.

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