US2247001A - Liquid fuel burner - Google Patents

Description

June 24,1941. M. A. BOWERS 2,247,001

LIQUID FUEL BURNER Filed June 27, 1958 2 Sheets-Sheet 1 LMI 3114x411 hw Fig .5 5:.:- 57.4

/V//fon A, Po Wens June 24, 1941; M, A- POWERS 2,247,001

LIQUID FUELURNER Filed June 27, 1938 2 sheets-sheet 2 E@ Ziff/fon A. Powers Patented June 24, 1941 LIQUID FUEL BURNER.

Milton A. Powers, Detroit, Mich., yass'ignor to The vTirnken-Detroit Axle Company, Detroit, Mich., a `corl'loration of v,Ohio n 'Application June 27, 1938,-seria1-No. 216,144

(Cl. 15s- 4) `8 Claims.

The present invention relates to liquid fuel burners, and especially to fuel burners of the type where a fuel distributor is disposed Silbstantially centrally of a hearth and designed to project the fuel substantially radially outwardly into surrounding parts fof the combustion chamber. 'The invention is especially concerned with an improved wall `tile 'designed to surround the fuel distributor adjacent the periphery of the hearth in or adjacent the region of combustion.

Aring of the :general type improved upon by the present invention is shown in several pat- :ents 4of the .prior art and in xmy v4Patent No. 2,130,471, dated September C20, 1938. However, my improvement -finds'greatest present value "on 'the conversion type instal-lationsi-n loil burners and furnaces Where it has been customary hereto- Afore yto install a row of refractory bricks or to form the wall :from molded hearth material, ,as a backing wa-ll i'over a portion or allot-the periphery lof lthe flame rim and 'located just 1oi-ltside 'of said flame rim.

The backing member formed 'by this wall is positioned radially `outwardly from the fuel impingement wall 'and extends a few inches above the height of the flame rim itself. In this position the wall serves as a substitute for the actual heat absorbing walls or combustion chamber of the -boiler yo'r furnace. Consequently, it serves several useful and important functions-not all @of which may be described Aon any particular installation. One Vof the most important functions is to maintain normal :combustion 'conditions over the length fof the iiame rim, backed by such member. This 'is best I'explained Where, for example, the flame rim is positioned at vary ing distances from the heat absorbing Walls as frequently occurs on a long rectangular hearth where the iiam rim yoccupies but a portion of the total periphery of the combustion chamber. In such cases very vpoor combustion will be obtained if no backing member is used.' vReference to my Patent No. 2,065,393., issued vDecember V22, 1936, and the discussion therein on combustion of the wall flame burner emphasizes the part played by` a wall member in proximity 'to the flame rim of a wallflame burner. y y

Another important function, particularly on 'warm air furnaces, is 'to prevent the intense heat r o'f the flame from `directly impin'ging against the metal wall which, it can be readily under- 's-to'od, materially accelerates its deterioration. ln such lacase it has been the general. practice to .install 'a V`backing member of `4clay refractory brick Aabout theentire inner periphery of the furnace wall,a1though the tile of this type have at various :times 'caused a number of troubles which will be discussed later.

A ring made of vclay refractory brick Vor tile is heavy, relatively expensive, of relatively 'short life, and is open to the further objection -that it has suiiicient porosity to absorb oil or oil vapors, and absorbs large amounts of fheat during the operation -of the burner, 'which heat radiates back and-has -destructive effects on the burner during the periods in which it is not operating.

lIt is, accordingly, vthe primary object of the Ypresent invention to devise animproved metal ring formed of a multiplicity of flexibly 4interlocked segments, thus improving on the earlier types of rings While maintaining any and :all advantages that were present in said earlier rings. rThe multi-segment ring of `this invention is easier 'to handle 'and more compactly bundled for rshipment than either brick or a vone-piece ring. It is vcheaper and lighter than brick, and more flexible than 4a continuous strip steel ring. The flexibility cfmy improved ring also eliminates any warping, distortion or slipping of the ring in use and facilitates installation.

VSpecifically then, it is a major object of, my invention to devise a multiple segment ring in which the vsegments may be readily and flexibly joined or interlocked, Veither at the factory as part of a complete apparatus or on the job for modern-ization purposes.

It is a further object of the present invention to devise a multi-segment metal ring having flexible joints which permit automatic vertical,

adjustments of the individual segments. In this connection it is also an objectto 'permit a limited amount -of vfiexibi-lity or adjustment circumferentially and radially of the r.ring to allow thermally induced expansion and vcontraction tov freely take place without throwing the wallout of proper alignment and without distorting the rparts thereof.

The vertical wall llame burner requires a generally circular ame ring for proper operation because the -oil and air are thrown toward the fla-me ring by a centrally located distributor head. Although the flame ring assembly may be of elongated or elliptical form, it has been found that in' rectangular furnaces which are being converted into rotary Wall flame furnaces it is impractical to make the flame ring assembly exactly conform to the 'rectangular walls.

In installations of this character spaces are left behind` the flame ring assembly which must be blocked oir to prevent the oil and air from being blown olf into those spaces and incorrectly mixing. Heretofore, it has been the practise to block oli such spaces with refractory clay segments and although they effect proper mixing of the fuel and air, they are not completely satisfactory because they do not t the combustion chamber exactly, requiring filling in with clay, they are heated to an excessive temperature and often crumble away, and they cool slowly, giving rise to pre-ignition diiculties.

It is quite apparent that the use of my metallic wall structure in place of the heretofore conventional masses of clay brick and molded refractory will result in a hearth construction of much less weight and consequently greatly reduced heat absorbing ability. In other Words, a hearth of my improved construction heats and cools very much more rapidly. This produces much higher combustion efliciencyearlier in starting as but little heat is absorbed by the backing structure and it quickly reaches maximum temperature. Furthermore, and probably of even greater importance, particularly in direct red warm air installations, much better room temperature control is possible in addition to improved burning eiciency.

On direct fired installations, there has been a marked tendency inspecifying equipment to provide a heating plant with relatively little excess burning capacity above the maximum heat requirements of the building. This is due to the fact that the rapid response of a forced warm air system will cause too rapid a rise in room temperature, following which the room thermostat is satisfied and considerable time may elapse before the next call is made for heat-resulting in a noticeable unevenness in temperature throughout the building. This undesirable condition is further accentuated by the flywheel eiect of the heat stored in the refractory in the combustion chamber, which slows down the heat delivery to the rooms at the start of the heating period due to heat being absorbed by the refractory. When the thermostat is satisfied, the hot mass gives up its heat, resulting in an overrun in room temperature which is highly undesirable.

With my light weight structure, this characteristic is eliminated and the desired room temperature exactly obtained in the shortest time with maximum burning efficiency during the entire period.

It is, accordingly, a further object of this invention to provide a metallic wall structure for blocking off spaces in furnaces embodying rotary wall iiame burners which are of simple design, will last indenitely without having its eificiency impaired, and which will heat up and cool rapidly, thereby obviating pre-ignition diiiiculties.

It is another object of my invention to devise metal ring segments of generally cylindrical curvature which may be used in varying numbers within a given range to produce rings of different diameters and shapes.

It is a further object of this invention to provide a joint for ring segments or the like comprising cooperating tabs and slots, the slots being wider than the tabs and the tabs having lateral indentations which facilitate bending them after insertion through the slots, and which also locate the bending lines so that the segments will be properly disposed relative to each other.

A further object is to devise a backing wall assembly for a Wall flame burner having an oblong shaped llame wall which is designed to materially improve combustion conditions therein.

'ing combustion chamber wall.

The foregoing and further objects of the present invention will become more clearly apparent from a consideration of the following detailed description taken in conjunction with the accompanying drawings and the appended claims.

In the drawings:

Figure 1 is a vertical sectional View through the bottom part of a furnace having the improved liquid fuel burning apparatus of the present invention mounted in its combustion chamber, substantially as it would be seen by looking upon the line I-I in the direction of the arrows of Figure 2 i Figure 2 is a horizontal sectional View through the apparatus of Figure 1 and shows the distributor mechanism and the various walls mounted on the hearth in top plan View;

Figure 3 is a face view cf one of the multiplicity of segments used to form the backing walls illustrated in Figures 1 and 2, the tabs on the segments being shown in their initial or manufactured position prior to bending; y

Figure 4 is a view illustrating the manner of joining a pair of the segments of Figure 3, the tabs in this assembly having been bent'to a position to flexibly interlock the segments;

Figure 5 is a sectional View taken through one of the interlocking joints of Figure 4 as seen when viewed on line 5 5 in the direction of the arrows;

Figure 6 is a vertical sectional view on an enlarged scale of one of the llame ring segments and shows how it cooperates with the backing wall;

Figure 7 is a top plan diagrammatic view somewhat similar to Figure 2 but shows a modified form of backing wall assembly; and

Figure 8 is a fragmental elevational View of one of the backing wall plates' used in the device of Figure 7.

With continued reference to the drawings and with particular reference to Figures 1 and 2, the reference numeral 8 designates'a base forming a compartment and having an upper inturned flange 9 which supports the hollow boiler section I0. A horizontally disposed ceramic hearth assembly indicated generally at I2 is molded in place on a metal plate 'assembly I3 which is supported by flange 9. vPlate assembly I3 is also supported in part by the distributor mechanism, to be presently described.

The distributor mechanism is indicated generally at I1 and is disposed centrally of the apparatus. 'Ihe hearth assembly is centrally apertured to permit installation of the distributor and to also allow the entrance of fuel and air into the combustion chamber, the fuel being thrown in solid droplets substantially radially outwardly by a pair of tubes I8, which rotate in'xed relation to and with a fan structure I9, the latter being designed in well known manner to spread a sheet of air outwardly over the hearth surface toward its periphery.

A plurality of heat resistant metal segments 20, each having a sloping wall 2| and an upright wall 22, are disposed upon the upper hearth surface substantially in concentricity with the surround- Surface 2I deflects the outwardly thrownrstream of air upwardly towards the top of the wall 22. Segments 2D are preferably formed of a sheet metal that has good conductivity and has high resistance to destruction by heat. In operation, the upper portion of wall 22 is impinged by the droplets of oil thrown outwardly from tubes I8. Segments 20 are preferably supported upon brackets 23 which have 'prongs embedded in .the hearth while 'the .latter is still plastic.

The .specific construction of the distributing mechanism and these brackets is described and claimed in my Patent-No. 2,065,393, granted December 22, 1936. The mixture of fuel and air is preferably ignited through electric means, for instance, a pair of electrodes 24 `operating to establish electric arcs between :them and ring 22. As the ignitor mechanism Yis` also shown -in "my aforesaid prior patent, and as no claim is `made thereto herein, .they will not 4`'be further shown ynor described.

After ignition has taken "place, a hot flame is propagated at the top 4of the wall 212, some of the llame passing upwardly and Vthen downwardly outside lof wall 22 to cooperate in' di-rectfheattransmitting relationship with the inner walls of the boiler sections.

'I'he apparatus thus `far described corresponds with that disclosed in my aforementioned patents, and the apparatus of my invention which makes it possible to mount a wall flame burner, which normally requires a circular or elliptical flame wall, in a rectangular or Voblong boiler, will now be described. Y

Referring to Figures 1 and 2, a large "dead space is located in the rear of the furnace and two smaller spaces appear nace between the furnace wall and the flame ring segments. These dead spaces 'are blocked foif as follows:

Disposed outwardly of segments 20, and disposed in substantially parallel` spaced relationship thereto, both at the front and rear of the boiler, is a backing wall 25 composed of a multiplicity of identical steel segments 26, the segments being flexibly secured together ina manner yet to be described to present, in eiect, a continuous surface outwardly of segments 20 at opposite ends of the boiler. Backing wall '25 is considerably higher than segments 20, approximately twice as high in the illustration, but the height may be varied as is found suitable, depending upon the factors of the particular installation at hand. Backing wall 25 maybe 'secured to the hearth by means of a plurality of brackets (not shown) having prongs embedded in the 'hearth and a Vpair of upstanding fingers between which the .individual elements of the backing wall may seat. In the drawings, however, I have 'illustrated the backing wall as seating snugly agains'tfthe hearth surface and supporting brackets 23 as being provided with fingers 21 whichv abut-the inner surface of backing wall 25 and maintain it in proper spaced relation tothe :flame ring. lf desired, however, elements 21 .may be fpar'tia'lly embedded in the hearth.v Y

Both of the backing 'walls 25 .terminate at each end adjacent the boiler wall, where the latter vis of flat coniiguration, and are located close 'to ring 22. In other words, walls Y25 vare only used in that part of the vchamber wherein the boiler wall is spaced considerably from seg-ments V2l] and would otherwise allow the products of combustion to eddy out into the large dead spaces and be improperly combusted. Walls '25 `also inoidentally function to prevent oil from splattering or splashing and thereafter accumulating f' remote from the flame ring where it would be difficult to vaporize, and it alsocooperates with the back of the impingement wall 22 to form a reverberatory chamber forvthe downwardly swirling flames and gasses of combustion, thus mainat the front of the furtaining vthe efllciency Iof 'Lheat transmission at the highest possible maximum.

If kit 'were'not for the "fact that, in the conversion installation illustrated, 'aclinker clean-out door 23 is located at the front of the boiler, and which iis filled vwith refractory cement so as to constitute `a dead wall, the backing wall rfor the'iront of -vthe furnace could be made in ltwo parts, so as to merely block olf the two corners and allow the flame `to cooperate directly with the front wall of the furnace.

'-Il-ie :segments 26 of the backing wall are formed of very thin sheet metal, such as chromium steel, that Ais highly resistant to distortion or destruction by heat and that does not easily bend out of shape in handling, The thickness is exaggerated in the drawinlgs for Yclarity of illustration. The segments thus `'are very light in weight and, be- 'ing of uniform rectangular size may be packed 4nicely for shipment and for ease of handling. An important feature of Vthe present invention resides in the means for flexibly interlocking the segments -to form -the complete ring. This feature will ynow be described in detail, with reference particularly to Figures 3, 4 and 5. Y Y,

Each plate or segment is of substantially cyl-indrical curvature and its height preferably is considerably greater than its width. Along one of itsvertical edges it has two or more (three in the illust-rated form) rectangular ,fastening elements '2'97 which are horizontally disposed and properly spaced with respect to' lone another vertically along the edge. Each element 29 is formed of vvery thin metal having substantially the same lcharacteristics as the metal of the segments 26, and it is arranged with one of its ends in surface contact `with the segment, to which it preferably is secured by spot .welding as indicated at v30. The vother end Yfof the fastening element thus projects `horizontally beyond the edge of the `segment 'to form a .tab 32. Horizontally aligned with this tab and disposed in the opposite yvertical `edge of the .segment isja slot 33V which is cut vertically and vwhich is considerably wider than the tab thickness and considerably longer than 'the tab Width. VThenumber .of slots, of course, Acorresponds with the. number of tabson each segment. l Y

T he tabs at the edge of one segment are readily inserted, just as they appear in Figure 3, through Ythe slots of another segment by disposing the two segments at a slight angle to each other and bringing 'their edges thatare to be joined into overlapping relationship. The angle of `disposition for performing this manipulation may be very small 'due'to 'the fact that the tabs pass freely :through 'the slots Vas a result of the fs'lot :dimensions-being 4considerably ygreater than those of the tabs.

Ylilach tab is -provided, adjacent the edge of the segment 'to which it is secured, 'witha pair of vertically aligned notches 31%, these Ynotcl'ies being located in the upper -and lower edges of the tab. After the tabs have been inserted in the slots in the manner set forth in the preceding paragraph, they may be readily bent into the position shown in Figure 4 by applying .force laterally to 'their outer ends. This stepis easily performed as a result of localized weakness produced by the notches 315. vThese notches 34 not only facilitate the bending operation, but they also definitely `and accurately locate the vertical lline Vof bend so that the joints between each pair of segments will properly position lthe matchedv edges of the latter to bring one into slightly overlapping relation on the other and afford, in effect, a continuous cylindrical surface through which the fuel cannot escape in a direction radially of the hearth.

The Width of each tab, between the bottoms of its pair of notches, is only about half the width of the slot in which it is confined, and thus each segment has considerable vertical play with respect to the others of the ring or backingwall. Each segment also has a circumferential play as a result of the width of the slot being greater than the thickness of the tab which it receives. In addition, the notches are sufficiently wide in a horizontal direction to permit each segment to have a slight radial play with respect to the axis of the ring.

The series of joints thus formed are very flexible and,l permit automatic adjustment of the segments relative to each other in all directions. As a result the entire ring will seat itself fully upon the hearth, and should any segment have a tendency to distort into changed shape as a result of high and varying temperatures, there will be little or no tendency for the entire ring to warp or pull out of place. The life of the backing rings is, therefore, equal to or greater than that of the rest of the oil burning apparatus.

As seen in Figure 6, brackets 23 are secured to supports 23a as by welding or the like and fingers 2 are formed as a part of the support and are of the requisite length to properly space segments 25 from segments 20, and if desired, they may be welded or otherwise secured thereto, so as to more firmly anchor the parts together. Brackets 23 are provided with tabs which are bent over to clamp segments 20 in place as seen more clearly in Figure 6.

The advantages of the metal backing wall over the refractory clay segments heretofore used are many. The ease of installation is apparent, the segments being selected in proper number to just exactly fill the space involved and may be arranged to assume any desired shape of wall.

Also, the metal segments, being thin and highly conductive, heat up and cool down rapidly, thereby eliminating preignition dilhculties, thereby allowing the burner to be restarted shortly after being shut down. The metallic segments, moreover, will not burn out or crumble as clay refractories have done in the past.

In some installations a set of metal grills of the type shown in my aforesaid Patent No. 2,- 055,3.93 and which are of a type now well known, may be mounted on the upper edge of segments 20 to shorten the ame of combustion.

Also, I have shown my invention incorporated in an apparatus having a ceramic hearth but it is to be understood that if desired it may be mounted in a furnace having a metal hearth, and in that case both segments 20 and 2E may be welded or otherwise suitably secured thereto. Also, the invention may be employed in combustion chambers having other than a* rectan.-l gular cross section if desired.

For instance, in combustion chambers which are substantially square in horizontal section, the backing wall of my invention may be utilized to block off the corner spaces. Also, I have shown a fuel burning apparatus embodying segments 20, but it is to be understood that the backing ring of the invention may be used with apparatus embodying two concentric upstanding rings which provide 'both an air deflecting wall and an impingement wall such as is shown in my Patent No. 2,107,800, dated February 8, 1938, and they may be disposed so as to denne a truly circular llame ring assembly or may deline an elliptical assembly.

From the foregoing, it is apparent that I have provided a novel and efcient apapratus for cornbusting liquid fuel andv it is, moreover, ideally adapted to the conversion of rectangular or other odd-shaped coal burning furnaces into wall llame burners since the installation of the backing wall is readily effected by selecting the proper number of metal segments required to ll the dead spaces and putting them in place on the hearth, thereby obviating the need for cutting or shaping the parts or using clay or other ceramic material to ll in gaps between the backing wall and the boiler sections.

The novel backing wall of the invention may be used in other relationshipsin liquid fuel burning apparatus of" the general type illustrated and in other types where a heat-resistant, light flexible ring is desired or needed.

In Figure 7 I have somewhat diagrammatically illustrated the parts shown in Figure 2 as coop- @rating with a modified form of backing wall which is shown more clearly in Figure 8.

It has been discovered that in some wall flame burner installations where the flame wall is of oblong shape, the flame will tend to creep into the regions designated as A in Figure 7. This is a distinct disadvantage because the flame is divided in two parts and ineffcient combustion and heat transmission results. I have found that by providing perforated backing plates 26a in the two regions designated 13, the flame is held in those regions and does not creep around and concentrate itself in the regions .A. One of the plates 26a is illustrated in Figure 8 and it is provided with a plurality of apertures 35 through which the flame may eddy and mix, thereby improving the character of the iianie. If desired, all of the plates 26 may be perforated as shown in Figure 8.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. 'Ihe present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated b the appended claims rather than,- by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are, therefore, intended to be embraced therein.

. What is claimed and desired to be secured by United States Letters Patent is:

1. In a liquid fuel burning apparatus, a conibustion chamber closed by a hearth, fuel projecting meansv at the center of said hearth, a fuel intercepting wall disposed outwardly from its center, a backing wall of greater height than said fuel intercepting wall and spaced outwardly therefrom in proximity to the hearth periphery, said backing wall comprising a multiplicity of upright thin sheet steel segments, each being of substantially cylindrical curvature and slightly overlapped on another, and means for retaining said segments in their upright overlapped relationship.

2. 'A liquid fuel burning apparatus comprising a hearth, fuel supply means located centrally of and above said hearth and designed to project liquid fuel toward the hearth periphery, a refractory ring located inwardly from the hearth periphery, and providing a fuel impingement wall facing inwardly toward the fuel supply means. and a backing wall adjacent the hearth periphery in parallelism with said refractory ring, said ring being materially spaced from said backing wall upon the hearth surface and the backing wall being materially higher than the refractory ring, said backing wall comprising a flexibly interconnected series of thin segmental plates of a material resistant to destruction by heat.

3. In the apparatus defined in claim 2, means for feeding air against said impingement wall in a manner to cause the flame of combustion to swirl downwardly into the space between said refractory ring and said backing wall, said wall and said refractory ring both being of metal of good heat conductivity, and the surfaces of said plates being smooth and mirror-like.

4. In the combination defined in claim 2, said plates being interconnected by joints that are slightly exible vertically, circumferentially and radially, whereby a change in shape in one of the plates will not warp the entire backing ring or move any portion thereof out of contact with the hearth. n

5. The combination defined in claim 2, with refractory bridge elements extending between said backing wall and said refractory ring for maintaining the same in accurately spaced relationship.

6. In a liquid fuel burning apparatus, a combustion chamber of generally rectangular shape in plan, a hearth structure mounted in said chamber, a centrally located distributor for throwing a blast of oil and air outwardly over said hearth, a flame ring assembly cooperating with said distributor and mounted on said hearth and being of generally curved form, said flame ring assembly lying in close proximity to the Walls of said chamber but being curved at the corners of the latter, and an upright metallic Wall structure disposed between said flame ring structure and the walls of said chamber for preventing said oil and air blast from blowing into said corners of said chamber. y

7. The liquid fuel burning apparatus described in claim 6, wherein said metallic wall is made up of a plurality of articulated segments.

8. The liquid fuel burning apparatus defined in claim 6, wherein at least a portion of said metallic wall structure is perforated, for preventing the flame from localizing itself in certain regions of said combustion chamber.

MILTON A. POWERS.

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