US2982350A - Conversion burner - Google Patents

Description

May 2, 1961 F. F. scHLljrT CONVERSION BURNER Filed Aug. 27. 195'? 5 Sheets-Sheet 1 A r roENEs/s 5 Sheets-Sheet 2 Filed Aug. 27. 1957 INVENTOR FOYD F- SCHL /77 BY R10/5y, WA 775, pesaro/va? M f/vf/v/vy May 2, 1961 F. F. SCHLITT 2,982,350

CONVERSlON BURNER IN V EN TOR.

BY R/cHEY, WA Trs, EoGERTo/v,

MSA/NNY FAR/w aro May 2, 1961 F. F. scHLlTT 2,982,350

CONVERSION BURNER Filed Aug. 27. 1957 5 Sheets-Sheet 5 IIIIIL INVENTOR. /c-OYD FZ SCHL/77' 2,982,350 CONVERSION BURNER Floyd F. Schlitt, 331 Cornell Ave., Elyria, Ohio Filed Aug. 27,1957, ser. No. 680,604 9 claims. (c1. 15s-11s) This invention relates to, conversion units for modifying domestic furnaces for use with gaseous and-vaporous fuels and, more particularly, to a new and improved fuel burner. l

An object of the invention is to Provide a conversion unit for domestic furnaces which` is simple and efficient and yet sufficiently compactto be installed4 in existing furnaces.

Another object of the invention is to provide a `compact furnace conversion unit of relatively high eiiiciency under all conditions of operation.

Still another object of the invention is to provide an improved gaseous and vaporous fuel burner vwhich in corporates an efcient means for `Secondary air control.

A further object of the invention is to provide an improved gaseous andv vaporous fuel burner in whichl a burner utilizes apilot burner in conjunction with a secondary air control;

A still further object of the invention is to provide an i improved combustion chamber `for burners for space heaters. An additional object is to prevent flame roll out over the full range of burner operating capacity.V

Another object is to eliminate the necessity for removing thefburner lspud fitting or disconnecting the spud from the main gas supply line when the burner is to be removed from or introduced into itscasing.

Patented May 2, 1961 centric members. The arrangement is such that the members may be constructed of refractory materials, while maintaining a simple andV compact construction.

It is an important feature of the conversion u nit of the invention that the burner element may be readily removed from the conversion unit after installation for servicing of the burner element.'

In lthe course of making this invention I made several entirely unexpected and unpredictable discoveries which have proven tobe quite valuable and important. In par-V ticular, I found that by providing an opening between the combustion chamber shell and the'top of the casing of a conversion burner unit a Very substantial improvement in the operating characteristics of the assembly can be consistently obtained. By making this space annular as. 1

by providing several spaced supports for thecombustion chamber shell and by maintaining the axial dimension of this annular space within certain limits, results `hitherto unobtainable can be secured in regular production model of the-burner assemblies of this invention.

I further found that the tendency for roll out of flame,

whichis particularly marked in conversion units' of this type in high capacity burner operation, can be eliminated by providing a form of haifle -at a particular location with respect to the burner nozzle in the units 'of this invention.

These and other discoveries that I made andthe new features that I have incorporated in the present assemblies are embodied or incorporated in theassemblies and apparatus described in detail below and illustrated in the drawings accompanying and forming a part of this specification in which:

Fig. 1 shows a partial section of the conversion unit of the invention as installed in a domestic furnace;

' Fig.. 2 is a plan view taken along the lines 2 2 in One method of overcoming the limiting conditions which occur inthe operation of gaseous fuel burners involves the Yuse of secondary air which is added-tothe name to complete the burning voft the initial combustion products of the dame. The method ishighly eicient but suffers certain disadvantages' whenV used in small burner unitsY due to the complexity of the apparatus required'to provide an accuratecontrol of the amount of secondary air.

'The present invention involves the use of. a burner,

structure in which theflow of secondary air isialong a path concentric with, but separate from the flow of the primary air-gas mixture ofthe` burner element proper. The combustible mixture formed at the burnerr nozzle is directed through van Lopening in a burner casing which surrounds the burner element and so that the iiame ex-` tends vertically through the opening 'in the casing. A

movable baiiie surrounds the nozzle and is adapted to be '60 moved toward andaway from the casing so asl to control the quantity of air which iiows` fromthe interior of the casing into the ame opening. The positionof the baffle may thus be adjusted for most efficient combustion of the fuel gases or vapors. f

vIn the particularembodimentof the invention disclosed herein, the. novel burner is incorporated in a gas conver-v sion unit for solid fuel furnaces and has-associated therewith a novel combustion chamber for imparting the heat generated by theflamekto the heat exchange elements of the furnace proper. Theflame deector is formed of refractory material and utilizes af no vel construction wherein the, flame passesl along a path between two conportions removed to show the arrangement of" the main Fig'. 8 is an elevational, longitudinal, sectional View ofy a conversion burner assembly embodying this invention ina preferred form.;

Fig. 9 is a top -plan'of the assembly of Fig. Swith upper burner and its` Spud ttinginthe burnercasing; Fig. l() is a longitudinal, sectional view of the secondary air regulatingdevice ofthe assembly of Fig. 8;

f Fig. ll is a top plan viewV of the regulator of Fig; 'l0;

Fig. 12 isv an end view of vthe Fig. l() regulator takenv on une 1212; 1

Fig; 13 is a vertical, sectional view of the burnernozzle ofthe assembly of Fig, 8 showing fragmentarily the nozzle discand means securing the discto the nozzle;

Fig. 14 is a top plan view of the-combustion chamber spacerplateof the Fig. 8 assembly; and,

Fig.: l5 is a verticaL',sectionaliview of the plate of Fig. '14 takenon line 15 -1S. Referring now to Fig. 1, the conversion unit i0 of the invention is shown as'installedin the ash box 11 of an v14 as is customary in the art.

ordinary domestic furnace 12. The walls of there pot 13 serve as a heat exchange medium for transmitting heat generated b y theconvers'ion unit 10 to a stream of air which isadmitted totheV furnace through a cold air inlet The conversion unit comprises a burner unit 15 for producing a combustible mixture of fuel and air and for supplying a suitable amount of secondary air to the ilaine generated by combustion of the mixture. Acombustion chamber 16 coniines the ilame of the burner unit in such a way as to provide optimum combustion conditions for the burning air-gas mixture. The combustion chamber also serves to deilect the products of combustion so as to facilitate the transmission of heat to the walls of the lire pot 13. The burner unit is of such a size that it may be inserted into the ask box 11 through the front door thereof while the combustion chamber 16 may be separately inserted and positioned atop the burner unit. Y

Theburner unit 15 comprises a sheet metal outer cas` ing 17 and a burner, including a burner element 18 mounted within the easing, and a secondary air regulator 19. The burner element 18 is of well known construction and includes a gas inlet 720, an air inlet 21 and a needle valve 22 for regulating the primary gas-air mixture. A burner nozzle 23,' mounted at the end of the burner element 18, may be of the same type as is disclosed in my copending application, Serial No. 254,067, filed October 31, 1951, now United States Patent No. 2,757,723.

A pilot burner 24 is mounted upon the burner element 1'8 and is supported adjacent an igition slot which is formed in the side wall of the burner nozzle 23.

The burner element 1S is supported from the bottom wall 25 of the casing 17 by a forward leg 26 and a rear leg 27. Flange portions 28 and 29 rest upon the bottom wall and provide lateral support for the burner element. The burner element is held in place by stops 30 so that the burner clement may be removed from the burner casing through the opening 31 for servicing. It is to be speciiically noted that because of the organization of the burner and pilot burner, it is particularly advantageous in that the position of the pilot burner is iixed and need not be disturbed when the burner element is removed for service. As a result, the usual dangers of explosion due to malpositioning of the pilot burner after the burner proper or the pilot burner is serviced are obviated.

The nozzle 23 is disposed below and aligned with an opening 32 in the upper wall of the casing 17. The combustible mixture from the nozzle 23 is directed through the opening 32 and combustion takes place in the region immediately above the nozzle.

The casing 17` serves as an enclosure for determining ilow of secondary air from the open end 31 of the casing to the opening 32. The air ilows along the casing and concentrically about the body of the burner element V18 and the burner nozzle 23 so that there is a uniform ilow of secondary air into the space above the nozzle from all sides of the nozzle. The rate at which this secondary air ilows into the opening and is supplied to the burning mixture is controlled by a secondary air regulator including a baille 33. The baille 33 surrounds the nozzle 23 andcooperates with the upper Wa1l'37 of the-burnerl casing to restrict the movement of the secondary air.

The baille 33 is of generally annular shape and comprises a horizontal portion 34 which has an opening 35 which is slightly larger than the outside of the nozzlev tremity of the nozzle 23. The baille 33 is supported by Y an arm 38 which is supported from the burner element 18 by a pivot member 39. The baille 33 isiixed in posi? tion with respect to the nozzle 23 by means of a set screw 40 and a second member 41. The members l39 and 41 form an integral part of the burner element so that the4 entire assembly may be removed from the burner casing 17 for servicing. ,y .l p

The combustion chamber 16 comprises'an outer portion 50 and a central portion or pier 51 which is disposed within the outer portion 50 so as to form a generally coaxial opening 52 between the two portions. The outer portion 50 comprises a sheet metal casing 53 which may be attached to the upper wall 37 of the casing by any suitable means and a lining comprising a flat annular member 54 and a cylindrical member 55. The lining members 54 and 55 are of refractory material and are supported by the top wall 37 of the burner casing.

The pier 51 is also formed of refractory material and comprises a lower cup-shaped member 56, a cylindrical central member 57 and an upper deilecting member 58.

i lower tapered portion 62 which forms a continuation of the side walls of the conical piece 60. As shown in Fig.

4, the pier members are provided with three radially ex tending ilns 63 which maintain the spacing of the pier members from the lining members of the outer portion 50 of the combustion chamber.

In use, the conversion unit is mounted in the ash box 11 of the furnace. The ash box opening is then closed by a sheet metal member so that the only air which' reaches the interior of the ash box 11 and lire pot 13 must pass through the burner casing and through the ilame opening 32. Positive control of the secondary air supply is thus assured by adjustment of the position of the baille 33 of the secondary air regulator.

Referring now to Fig. 5, there is shown an alternate embodiment of the secondary air regulator of the invention. The baille 64 is similar in cross section to the baille 33 of Fig. 1 but is formed in two semi-annular pieces 65 and 66. The pieces 65 and 66 are supported by arms 67 and 68 and are, in turn, supported by two pivot members 69 and 70 which are secured to the burner casing 17. The pieces 65 and 66 may thus be moved toward and away from each other and from the burner nozzle to control the quantity of secondary air moving into thc space above the burner nozzle-23. The ends of the arms are disposed within the burner casing and may be used as handles to adjust the baille pieces. The top part of the vertical wall portion of the baille members is, of course, separated from the top wall of the burner casing by a small amount so as to minimize the ilow of secondary air between the baille and the casing while permitting horizontal adjustment of the baille pieces.

Referring now to Fig. 6, the alternate embodiment of the combustion chamber incorporates a central pier which` y is supported by a lower pier member 71 rather than by a separate metallic piece as in the embodiment of Fig. 1. The lower pier member 71 has conical lower portion and is supported by a plurality of radially extending iins 72 which rest upon the ilat annular member 73 of the outer portion of the chamber. The central pier member 74 is provided with radial projections 75 which maintain the spacing between that-member and the cylindrical outer member 76. The combustion chamber members are, of course, formed of refractory material.

Referring now to Fig. 7, thee is shown an alternate embodiment of the combustion chamber which is generally similar to the chamber of Fig. l in that it incorporates a metallic pier support. The outwardly projecting portion 77 of the upper deilecting member 78 is, however,

p tapered upwardly to modify the path of the products of combustion as they leave the combustion chamber.

,The burnerrassembly illustrated in Figs. 8 and 9 is i basically similar to that of Figs. 1 and 2 in that they both incorporate thc-same certain novel features of this in-A cludes additional features and `embodies` additional discoveries of mine specifically mentioned above.

' This latter assembly thus comprises, a sheet metal burner casing which has an opening at oneend indicated at 81 which serves as bot-l1 an access opening and as anair inlet opening for main burner and pilot burner primary and secondary :air supply. In the top wall of casing 80 remote from end 81 -a flame opening 84 is provided. A straight rail85 and an angular rail S6 are spot welded to the bottom Wall of casing 80, and `located with respect to each other and` to ilame opening 84-so as to insure alignment of the main burner nozzle with the flame opening when the burner is installedk in the casing.`

Main burner 87 as shown in Figs. 8 and 9 islpositioned withits axis at a small Vangle tothe longitudinal axis of the casing and with ,its leg-S8 wedged between the rails 85 and 86 near their iner'ends and its leg 39 abutting rail 85 near its outer endf-k Burner spud fitting90 is disposed coaxially ofthe main burner and adjacent to the inlet end thereof in` accordance with standard practice andre'-l quirements. This spud Vtting is semi-.permanently fixed to the bottom wall of the housing. vIn other words,- ac# cording to standard requirementslis not readily removed from its original position; The main gassupply line 92 is connected to the spud fitting and byvirtue of the easy removability of burner V87 without `disturbing the spud or disconnecting the main gas supply line, the entire gas,

supply system may be left undisturbed when the burner is to be replaced or repaired. Rails v85* and 86 as indicated in outline on Figure 8 permit swinging'of the inlet end of burner 87 away from spud A90 in 'order to clear the burner for withdrawal from engagement with the rails and through opening 31 between the spud ittingand the opposed side wall of casing 80.' i

Pilot burner 94 is suitably the same as" pilot burner 24 of Fig. 1 and thus islocated with respect to main burner' nozzle 95 so as to servethe `burner after the manner described in rnycUnited States Patent .No/2,757,723, granted August 7, 19546f Details` ofY construction of my" patented nozzle 95 are illustrated in Fig. 13 wherenozzle,

discV 97 is secured in position `on topY of the nozzle by.

means of self tapping screws l98.

6 ported by Aburner casing 80 and consists of two. basic elements, namely a hollow refractory body l12,1 and a spacer plate 122 to support body 121 in vertical spaced relation to casing80 to provide an annular opening 124 for gas ow between body 121 and casing'80 to relieve combustion chamberpressure during main burner ignition. In addition, as shown inrFig. 8the combustion chamber will normally include a center pier 125 in body 121 and means including three Alegs 126V (two shown in Fig. S) for ipporting the pier in position above llame openlng Y i Refractory body 121 may suitably be of cylindrical or polygonal form'but it'must be open at its two ends and Y in accordance with this invention'it must be disposed above casing 80 to provide 'annular space 124.. In addition the refractory body shouldbe composed of material suitable for service *over long periods of usejunder the conditions of maximum capacity of the burner and the furnace in which this assembly is installed. It' isralso desirable that refractory body 121 be centered with respect to theburner nozzle and darne opening 84 and that it be substantially uniformly spaced. radially vfrom centerY pier 125.

Spacer plate 122 comprises a thin lmetal sheet or bed plate 123 which has a 'central opening 127 closely ap-v proximating in size and shape flame opening S4 in casing ing 127 with'their inner ends adjacent tothe inner V pe-y riphery of the bed plate. These rails, as shown in Fig'. l5, Vare angle irons which have been formed with upstanding tabs 131 Yat their ends remote from opening 127 so` thatthey provide lateral abutments to guide and hold yrefractory body 121 in centered position with respect to Yllame opening 84 and thev nozzle of burner 87. The

Control over flow of secondary air for both the main burner and the pilot burner is afforded by the apparatus shown.v in Figs. 10 and 1'1. This apparatus, which'isalso shown as part of the assembly of Fig. 8 in' closed position and in outline in open position, includes a cup-shaped body `or secondary air cupr100 having an enlarged centralv a rigid handle or operating lever-.1012 supported by ak pivotal connection to a supportingbracket'so that gravity will tend to maintain thecup in ,wide open position. Thel pivoted connection is' made by means of pin 104 disposed through registered openings 10e kinrlever i102 andthrough an opening in a supporting bracket 107 for the` secondaryl air control apparatus Vmounted on burner 87.

Lever 102 is made up yof a channel 108 which is welded v lto the` bottom of cup 100, a channelk109 in the sides of which openings arep-rovided-vand `a pair of metal fastening straps 110 and 111 which are welded to the` adjacent ends of the channels 108'and` 109, holding thema rigidly. together with the channels-opposed` to each other `as shown to best advantage in Fig, l2.) A nut 114 is Weldedtofthepweb 'of channel 109 near its .-free end in` l register with an opening in fthe hannel'web to receive an .screw-115 shown inlFig. 8.` Screw 11'5, bears atall` times i against Aa` uflangefportion of bracket107 tovmaintain bodyr 100 in predetermined` positionwith` respect to burner 87 screwL 115 -as indicated inV Fig. 8,`

Combustion chamber `is;4 maintained onfand'fsnp- .LILO

upper edges of these rails or irons extending inwardly from tab 131 engagethe lower end or edge portion of refractory body 121 and support the body in upright po# sition and spacedv relation to casing 80. The height of *i these rails above bed plate 123, except for the tab portions. 131, is preferably carefully iixed in accordance with this invention to provide the optimum dimensions of gap 124.` I have found, for example, that in gas conversion burners ofV this invention designed for the ordinary heating furnace using a `burner of maximum Vcapacity in the range of 400,000B.t.u., per hour maximum,4 gas input rating, gap 124 should be about 1%: inches high (axial I dimension). n

Three rails 13-5 whichappear U-shaped in plan view are welded to plate l2-3'atlocations 120 degrees apart around the inner periphery of. thef bed plate. These rails are modi-tied angle irons, the flange portions of which are disposed against and welded tothe" upper faceof the bed plate 123 whilethe `inner ends are situated adjacent to opening 127. These rails in cooperation with the bed `plate'nthus provide pockets in which to receive the lower ends of legs 126, `this relationship being illustrated in Fig. 8.

Pier Y125 comprises a conical, metallic, support member 1;'38`to-which the upper ends of` legs 126 are welded; a

cylindrical, central, refractory member V139 which rests on the inverted base of conical member 13S and an `upper l refractory deflecting member 140 which rests on the upper eter of the base of support member 138, while the'diam-V eter of` deflecting member 140 is` substantially greater,

Yapproximating the. inside diameter of body 121. This pier assembly isV supported Vin position in the combustion chaming of' burner nozzle 95.

7 With 4the'parts of the combustion 'chamber thus located with `respect to each other the best flame flow patterns and operating characteristics of the entire conversion burner apparatus will be obtainable. Flame entering the combustion chamber through fiame opening 84 will flow substantially uniformly through the combustion chamber and produce maximum heating elfects.- At the same time the burner and burner nozzle and Vother parts within casing 30 will vnot be subject tol high temperatures in the range of combustion chamber temperatures in operation or exposed to radiant heat in large amounts as is typical in prior conventional burner assemblies. This combustion chamber in other words will operate more efficiently and at a higher temperature Vand higher heat level on a given gas4 input, and the burner components in casing 80 will operate atA substantially lower temperature levelspthan the corresponding elements of prior art devices of this general type.

I have found that under certain circumstances nozzle disc 97 will function not only to prevent flame roll out as it cooperates with gap 124, but also this disc will control the secondary air supply in cooperation with adjacent portions of casing 80. Disc 97 in the illustrated embodiments is not adjustable in position relative to the burner casing but its initial position may be established infaccordance with predetermined secondary air requirements of normal operation of the main and pilot burners so that no additional secondary air control or regulation means such as cup 100 will be repaired to make the apparatus operate properly and efficiently.

While the novel burners and combustion chambers have been particularly illustrated and described with reference to conversion units for a Warm air heating system, it is nevertheless intended that the apparatus be equally useful in connection with hot water andsteam boiler systems either as conversion units or in original installations.

This is a continuation-in-part of my copending application Serial No. 389,274, filed October 30, 1953, and entitled Conversion Burner.

Having thus described this invention in such full, clear, concise and exact terms as to enable any4 person skilled in the art to which it pertains to make and luse the same, and having set forth the best'mode contemplated of carrying out this invention, I state that the subject nace and having top, bottom, end and side Walls, thev casing defining an air inlet between said top and bottom walls and a fiame opening in the top wall remote from said air inlet, a burner in the casing, the burner including a nozzle, the burner being fixed to the bottom' wall thereof with its fuel inlet at said air inlet and the nozzle aligned with said ame opening and spaced below said top wall, and means for regulating the air flow through said ame opening including a baffle in the casing around said nozzle and movable toward and away from said top wall, and means in the casing pivotally supported by said burner and carrying said baie.

2. The combinationl of `elements set forth in claim 1 in which a pilot burner is mounted on said burner to receive primary air at a point below the baie and secondary air at a point above the baffle and in whichsaid baille is provided with a recess to receive said pilot burner.

3. The combination of'elements set forth claim l in which said casing is provided with a combustion cham-- ber on the top wall thereof around said fiameop'ening` asaso 4. The combination of elements set forth in claim 1 in which said casing is provided with a combustion chamberk including a metal shell attached to the top Wall of the casing around said fiame opening, and a refractory liner within said shell to provide a combustion space coaxial with said burner.

5. A burner unit comprising a burner casing having top-and bottom walls, an inlet opening at one end thereof and a flame opening in the top wall of the casing at the remaining end thereof, a burner comprising a burner element having an inlet end thereof at the inlet end of the casing and a nozzle at the remaining end of the burner element and disposed below the top wall of the casingand aligned with the llame opening,

means secured to the inside of the burner casingfor removably mounting the said burner in the burner casing, ignition means comprising a pilot burner mounted adjac ent the nozzle and supported by the burner, and a sec- Y ondary air regulator comprising an annular baffle surrounding the nozzle and carried by an arm and a pivot for the arm mounted upon the burner, to permit vertical movement of the bale relative to the nozzle and the top wall of the casing, whereby the said burner, the said pilot burner and the `said airregulator are fixed with respect to each other and constitute a unitary apparatus which may be removed from the burner casing through the inlet vend thereof.

56; A gas conversion burner assembly comprising a burner vcasing having top, bottom, side and end walls,

the casinghaving an air inlet between the top and bottom walls and a flame lopening in the top wall remote from the air inletopening, a burner in the casing, the burner includingV a nozzle having an outlet opening aligned with and below the flame opening, and a combustion chamber above the casing including a hollow refractory body open at its ends and means for supporting said body above the casing top wall in vertical 'spaced relation tov the casing to provide an annular opening to relieve combustion chamber pressure during main burner ignition. n

7. In a burner unit including a casing having top, bottom, end and side walls, Va ame opening in the top Wall, a burner in the casing with its nozzle aligned with the casing flame opening, and means for regulating secondary air fiow through the casing flame opening including a cup-shaped body within the casing and having an enlarged central opening to receive the burner and a lever for moving that body toward and away from thel casing v top wall, the combination of a disc carried by the burner and having a diameter greater than said cup shaped body central opening, said disc cooperating with the cup-shaped body to prevent flame roll-out when the body is in open position and said disc being in substantially annular abutment with the cup shaped body to prevent flow of secondary air around'the burner nozzle when the body is in closed position.

8. A transportable conversion burner unit comprismg acasing to be insertedlin the ash pit of a domestic furnace and having top, bottom, end'and side walls; the caswall thereof with the nozzle aligned with said flame open- 'ilo ing and spaced below said top wall, a burner spud fitting in the casing and fixed to the bottom thereof, and burner guide means comprising rails secured to the casing bottom wall and disposed relative to the spud fitting and the flame opening to guide the burner in travel relative to the stationary spud fitting during burner removal from and introduction into the casing whereby burner replacement arid repairs can be accomplished Withoutdisconnecting the spud fitting from its lmain gas supply line.

9.- In a burner unit including a casing having` a liame opening in its topwall' and a burner in the casing with its nozzle aligned with the casing ame opening, the combination of a cup shaped body having an opening in the bottom thereof, the body being disposed around and spaced from a portion of the burner with the burner projecting through said opening, a disc connected to the top of the burner in annular abutment therewith and cooperating with the cup-shaped body to prevent flame roll back and to regulate the supply oi?k secondary air to the burner, said disc having a diameter greater than the diameter of the opening in the bottom of said cup shaped body, and means interposed between the cup shaped body and the casing to adjustably move the cup shaped body relative to said casing and relative to said burner and to selectively move said cup shaped body into substantial annular abutment with said disc with the disc disposed 15 within the cup.

1,640,284 Mitchell Aug. 23, 1927 Wetherbee Oct. 30, Power Mar. l0, Hassmer July 5, Pattinson Feb. 14, Heller Feb. 21, Zink Mar. 7, Torpy Feb. 6, West Feb. 13, Christenson Apr. l0, Norman July 10, Jones Mar. 9, Du Fault July 27, Corsiglia Aug. 3,

. FOREIGN PATENTS Netherlands Feb. 15, Denmark Oct. 22,

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