US2814338A

US2814338A - Gaseous fuel burner

Info

Publication number: US2814338A
Application number: US224087A
Authority: US
Inventors: Eric H Ryden
Original assignee: SCAIFE Co
Current assignee: SCAIFE Co
Priority date: 1951-05-02
Filing date: 1951-05-02
Publication date: 1957-11-26
Anticipated expiration: 1974-11-26

Description

NOV. 26, E H RYDEN GASEOUS FUEL. BURNER Filed May 2, 1951 NII 1N VENTOR WWK vEPYH; H. RYDEN 'BY :Myw'

ATTORNEYS United GASEOUS FUEL BURNER Application May 2, 1951, Serial No. 224,087

12 Claims. (Cl. 158-116) This invention relates to burners for use with natural, mixed and manufactured gases, and particularly to gas burners of the type employed in domestic heating, and to gas conversion burners which may be installed in gravity and forced warm air furnaces or hot water and steam heating boilers originally designed for burning solid or liquid fuels, and provides a single port, self-piloting, flame-retention type burner which is unique from the standpoint of its precision and safety in operation, relative simplicity of construction, ease in maintenance, and low cost of manufacture.

In the present invention, the burner provides maximum flexibility of operation undery varying conditions of air and gas supply. The air-gas mixing and discharge assembly includes a venturi mixing tube wherein the gaseous fuel is mixed with primary air and a coacting burner tube formed with an upturned extension that terminates in a burner head at the top of the extension, the burner head being of the single port type and having approximately the same cross-sectional area of opening as the burner tube passage in order to avoid the devel opment of static pressure within the tube and burner head during operation.

Heretofore, burners of this type have been used principally for high fuel input rates at elevated pressures wherein the outlet ports in the burner heads are smaller in total cross-sectional area than the fuel inlet, thus producing static pressures within the mixing tube during operation of the burner.

While these previous designs are suitable for large capacity burners, they are subject to what is known as flash-back or concussion upon extinction of the flame. In the present invention, a burner head is provided of the open single port type, which develops little or no static pressure and which gives superior fuel burning characteristics and quiet, non-concussive combustion during all phases of operation at all rates of fuel combustion.

An inherent disadvantage of the single-port type burner has been the fact that the air-gas fuel mixture upon its exit from the head of the tube may possess a higher velocity than that of flame propagation, thereby causing the llame to blow olf or become extinguished, and it is the major object of the invention to provide a novel burner head that eliminates this difficulty.

An object of this invention is to overcome the abovementioned diiculty by providing a special burner head representing an improvement over the burner disclosed in United States Letters Patent No. 1,978,477 issued October 30, 1934, to G. R. Robertson, and which is particularly well adapted for use in domestic type gas burners.

Another object is to provide a novel, safe, compact, economical gas conversion burner which is comparatively easy to service and maintain.

Further and other objects and advantages will become apparentgas the disclosure proceeds in conjunction with the appendedclaimsand the .accompanying drawings, in

which;

`atent AO asians Patented Nov. 26, 1957 Figure l is a longitudinal vertical sectional view of the gaseous fuel burner assembly of this invention;

Figure 2 is a sectional plan view of the burner head taken along the line 2--2 of Figure l;

Figure 3 is a vertical sectional view of the burner head taken along the line 3-3 of Figure 2.

Referring now in detail to the drawing, the air guide structure includes a housing 10 of generally box like construction formed preferably of sheet metal and having a front wall 12, a rear wall 14, joined by parallel side walls 16 and parallel top and bottom walls 20 and 22. This housing is so formed that the top, rear, and portions of the side walls are removable as a unit from the remainder of the housing to facilitate servicing of the burner parts therein. The confines of these walls dene an air intake chamber 23. Air enters this chamber through an aperture 24 which is formed through the front wall 12 near the top thereof and which extends longitudinally thereacross. Air outlet duct 26 is generally rectangular in cross section being defined by parallel side walls 28 and parallel top and bottom walls 32 and 34 and is fixed to and extends from the front wall 12 of the housing 10. This duct 26 forms a secondary combustion air passage from the intake chamber 23 to the combustion zone within the furnace.

In order to control the amount of air entering the air intake chamber 23 through the aperture 24, a shutter or door 36 is pivotally mounted by a hinge 38 on the wall 12 below the aperture 24. A rod 40 is pivotally connected at 42 to door 36 and provided at its opposite end with an outwardly turned extension 44 passing through an elongated slot 46 formed through the side wall 16 to be threadedly engaged exteriorly of Wall 16 by a lock nut (not shown).

Rod 40 and the coacting nut provide a means for supporting and fixing shutter 36 in the desired position re1- ative to aperture 24 for controlling the quantity of air entering chamber 23.

The formation of this air guide structure embodies certain safety features which should be noted in particular. As is best shown in Figure 2, wall 12 is provided at its top edge with an outwardly extending ange 47 which extends completely across the top edge to provide a protecting ledge which, when the burner assembly is placed in its operating position, abuts against the exterior furnace wall to prevent foreign material from falling into a position to block the air intake aperture 24. Further, the construction and mounting of the shutter 36 is such that it is normally biased toward its fully open position so that, should the locking means for its support become loosened, it will move to its open position rather than to its fully closed position, thus eliminating the possibility of shutting off the air supply completely.

Fuel control subassembly The fuel control subassembly includes a pressure regulator valve 48 of the diaphragm type and a solenoid actuated gas control valve 50, the outlet port of the former being connected to the inlet port of the latter by a suitable conduit. Gaseous fuel is supplied to the inlet port of the pressure regulator valve from a supply conduit through a manually operable main shut-off valve (not shown) to which the inlet port of pressure regulator valve 48 is connected by a suitable conduit. Gas control valve 50 is of a conventional type having a normally fully closed position and actuable by a solenoid to a fully open position, the energization of the solenoid being under control of a conventional room thermostat. The gaseous fuel is conducted from the outlet port of the gas control valve 50 through a suitable conduit, designated generally at 56, which in the disclosed form of the im valve 50 to the primary combustion air and gaseous fuel mixing assembly designated generally as 58.

Primary combustion air and gaseous. fuel mzxngassembly Assembly 58 comprises a U-shaped support member 60 having one end wall 61 extruded as indicated at 62 to form a converging bell shapedthroat for a venturi mixing tube generally designated as 63 only the end of the diverging portion 64 of which is shown, As is best shown in Figure 2, the tapered tube forming this diverging portion 6,4 is supported in coaxial alignment with the extruded throat 62, its end being Xed within a recess 66 formed in the outer end of the extruded portion 62. The opposite end wallA 67 of support member 60. is provided with an aperture 68 through which is fitted the reduced end portion 69 of a collar 70. Collar 70 is formed with a coaxially aligned bore through which a burner orilice spud holder 74 extends. Spud holder 74 is secured in the bore by a set screw 76. Spud holder 74fhas an externally threaded end portion 78- by which it is connected to the exit endof the conduit 56 leadingfrom gas control valve 50. An orifice spud 80.havingla'cylindrical aperture or orifice, formed coaxially therethrough is threaded tightly into the, OPpOSite end of spud holder 74; Sleeve, 84 surrounds spud holder 74, its end extending withinra recess formedwithin the end` of collar 70 in coaxial alignment therewith. Sleeve 84 is fixed within that recess by a set screw 88. The gas to be y burned emerges from the orifice intoventuri tube 63 and primary combustion air, is introduced into the venturi tube 63 around the gaseous fuel stream ,as will appear.

Inforder'to control, the lproportion of primary conibustion` air so introduced, an adjustable air flow control structure is provided whichhis mounted on the sleeve 84. lathe-.preferred embodiment of this invention, this adjustable air flow 'controltstructure comprises shutter 90 which is formedwith a radially extending ilange portion 92 andan integral hub portion.v Shutter 90 is mounted for longitudinalmovement along the exterior of sleeve84, a set screw 96 being provided for locking it in adjusted position.

By this construction, gaseous fuel is directed by the orifice spud 80 coaxially into the throat of the venturiV mixing Vtube 63 andl primary air enters the throat of the venturi mixing tube from the air inlet chamber, of the housing within which the mixing assembly 58 is locatedrin surrounding `relation to this centrally introduced fuel stream. The primary air stream defined byv flange 92 4and'wall61 is thus an annular air stream surrounding the enteringY fuel charge,and axial adjustmentl of ange 92 controls the effective air intake opening. The quantity of air passing into the venturi mixing tube is thus determined by the axial position of the flange prortiong92 of theair shutter 90 relative to the extruded venturi throat of the end wal1,61 of the support bracket 60. Once the proper position of air shutter 90 has'been determined, it is locked in placeon sleeve 84 by set screw 96 and need not be again disturbed,

It should be noted, that the burner Spud holder 74 may, after loosening set screw 76, be slipped axially from sleeve 84 and collar 70 of the mixing assembly without disturbingthe adjustment of the air shutter 90. Due to this construction, when it becomes necessary to clean, adjust or replace the pressure regulator valve 48, the gas control valve 50 (both shown in Figures 1 and 2), or the orifice spud 80 (shown in Figure 6), these elements can be removed as a unitary subassembly merely by loosening theset screw.,76, decoupling the conduit 54 from the manuallyoperable shut-otfvalve to which it is connected by.aconventional union connection, and removing the connection to one other conduit.

Asis best shown in Figure2, the diverging portion 64 of 4the-venturi mixing .tube-63 terminates in a substantiallypylindrical portion 100.` A conduit or burner tube- 102, which is of substantially constant circular cross section throughout its entire length and which, in the position shown, closely surrounds the diverging portions 64 and the cylindrical portion 100 of the venturi mixing tube 63, forms an extension thereof of variable length for directing the intermixed fuel and air to the combustion zone within the furnace. Burner tube 102 is supported at one end by a channel member 104 within which it rests and to which it is secured as by welding and at the other end by a support member 106 within the bottom of the tubular air conduit 26. A bolt 108 threadedly engages a nut 110 welded to the channel member 104 to serve as an adjustable support leg for the forward end of the burner tube.

Burner head and flame deflector The burner tube 102 terminates in an upwardly turned portion indicated at 126 at the end of which is provided a flame retention type burner head assembly 128. The flame retention burner head of the present invention is, as previously indicated, an improved form of the type disclosed in the aforesaid Robertson patent. As is best shown in Figures 2 and 3, this assembly comprises a collar 130 and a spider 132. Collar 130 is essentially cylindrical in cross section and is provided with a plurality of equally spaced longitudinally extending depressions or dimples 134 of the same size formed inwardly along its outer surface which serve to locate the outer diameter of the cylindrical spider rim 135 in radially spaced relation with respect to the inner diameter of the collar to provide a substantially annular passage consisting of several arcuate passages 136 for permitting liow of part of the gas air mixture between the collar and the spider.

The collar 130, as is best shown in Figure 3, has a lower cylindrical portion 131 of reduced cross-sectional area which is press-fitted upon the end of the burner tube 126. The collar 130 is so positioned relative to the end of the burner tube 102'by a plurality of studs 138 passing through the wall of the collar 130 that an annular opening is formed between the bottom edge of the rim 135 and the coaxially aligned upper edge 141 of burnerK tube portion 126, through which opening some of the intermixed gaseous fuel and primary combustion air may pass into the substantially annular passage at.136. Since thestuds 138 rest on the edge 141 of burner tube portion 126 and the bottom edge, of thev rim 135 rests on-the studs 138, the widthof opening 140 is determined by the diameter of studs 138. By this construction the major portion of the intermixed gaseous fuel and primary combustion air passes through the burner head interiorly of the rim 135 while a smaller portion passes radially through the annular opening 140 and upwardly through the passages 136. Due to the change in direction of the ow of the gaseous mixture necessary to enter the annular passage at 136, the gases passing therethrough leave the burner head at a lower velocity than the exit velocity of the gases of the main jet. The velocity of the gasespassing `through these arcuate passages 136 is sufficiently small so that the rate of flame propagation is equal to or greater than the velocity of the gases so that the tendency of the flame to blow-off the burner head is eliminated.

A circular deector plate 142 is mounted directly above the exit opening in the burner head. 128 and is suitably formed as shown, to direct the stream of gaseous mixture outwardly toward the walls of the `combustion chamber. The flame deflector 142 is axially fixed upon the upper end of a support rod 144 which is in turn supported in its vertical position coaxially of the burner head 128 by the hub portion 145 of the spider 132 of the burner head. The manner in which rod 144 is supported is best shown in Figure 2. The spider 132 is preferably formed of two similar scroll like members 146 and 148 suitably secured together at 150 and 152 as Aby tack welding -and being fonmed of stainless steel strips. Members 146 and-148 asians are formed with arcuate portions at 154 and 156 respectively which after the members are 4secured together and mounted within collar 130 dene a compressed resilient hub or a substantially circular opening having resilient walls through which the rod 144 extends. Due to the resiliency of the spider structure, the

arcuate portions

154 and 156 are pressed against the rod 144 with sutlicient force to hold it in alignment with the hub portion 145 of the spider.

Stops

157 and 158 are attached, as by Welding, to the rod 144 to support the flame deector 142 in the desired position above the burner head 128. Stop 157 locates the deector 142 on rod 144, and stop 158 limits the downward movement of rod 144 into the spider hub.

, Burner ignition assembly 'f This assembly includes a conduit connected to the vent openings of both the pressure regulator valve 48 and gas control valve 50 for discharging any gas escaping from these valves directly into the flame so that it will be burned, the conventional automatic pilot connected to the main fuel supply conduit for the ignition of the burner, and a runner tube for determining whether the pilot is ignited and for facilitating ignition thereof in the event that it has become extinguished.

The venting conduit for the pressure regulator valve 48 and the gas control valve 50 comprises, as is shown in Figures 1 and 2, a street T connector 160 which is threaded into an aperture through the wall of the control chamber side of the pressure regulator 48 which is connected through a duct 162 to the vent aperture of the gas control valve 50, and which is connected to one end of a tubular conduit 164 which extends through the air duct 26. Conduit 164 is formed at its opposite end with an upwardly turned portion terminating in an upwardly facing opening adjacent the pilot flame so that any portion of the gaseous fuel collecting in the vented side of the pressure regulator valve 48 or gas control valve 50 will be discharged directly into the ame at the burner head and burned rather than discharged into the atmosphere.

The safety pilot assembly is of a generally conventional design, comprising a fully automatic pilot 168 to which gaseous fuel is supplied from the main supply conduit (not shown) through conduit 170, T connector 172 and conduit 174. A conventional thermally responsive electrical switch mechanism 176 (Figure 1) is mounted adjacent the pilot assembly 168 and is of such construction that so long as the pilot 168 is ignited, the switch will be maintained closed and will assume an open position if the flame of pilot 168 has become extinguished. 'I`he switch of this mechanism is connected by wiring (not shown) in the electrical control circuit of the solenoid of the gas control valve 5t) so that if the pilot 168 has become extinguished the solenoid of valve 50 cannot become energized to open valve 50 to permit introduction of the gaseous fuel into the burner.

lA runner tube ignition is provided for reigniting the pilot and burner in the event that its flame has become extinguished. This runner tube ignition comprises a tubular conduit 178 terminating adjacent the pilot 168 and connected to a normally closed valve 180 actuate to its open position by push button 181. The inlet port of valve 180 is connected to the main fuel supply conduit through T connector 172 and the conduit 170. The wall of the tube 178 is pierced with many small slots along its length to permit escapeof a part of the gaseous fuel introduced therein. In order to determine if the pilot 168 is ignited, itismerely necessary to open the valve 180. If the pilot is ignitedpthe pilot flame will ignite the gas escaping through the slots along the tube 178 back to a point where the llame becomes visible. 1f the pilot is not ignited, in order to ignite the pilot it is merely necessary to open the valve 180 and hold a lighted match adjacent the valve end of the runner tube 178 to ignite the gas escaping through the slot in the wall thereof. After this escaping gas'is once ignited, the flame will pass along the runner tube 17 8 toward the pilot 168 and ignite the pilot.

The three

tubular conduits

164, 174 and 178 are connected together and mounted so that they may be readily removed as an assembly for servicing or replacement of the parts thereof. These three tubes are connected together by a bracket 182. In order to support this assembly at its forward end, a supporting bar or rack 184, which extends substantially chordally across the arcuate portion of the burner tube 102 and which is suitably secured to the exterior thereof at its opposite ends as by welding, is provided with a notch 186 which receives a clip 188 which is fixed to the mounting bracket 190 for the thermal responsive switch assembly 176 and the pilot assembly 168. Bracket 190, which is L-shaped, supports the forward end of

conduits

178 and 164 in addition to supporting the thermal responsive switch assembly 176 and the pilot assembly 168.

Referring now to Figure l, the opposite end of this ignition assembly is supported by an L-shaped bracket 192 secured to the Wall 12 of a housing 10 at one side of the opening formed by the air duct 26.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by 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:

l. In a gaseous fuel burner, in combination with a tube of substantially constant cross-sectional area terminating in an upwardly facing opening and adapted for guiding a gaseous fuel and air mixture to the combustion zone of a furnace, a llame retention burner head secured to said tube over said opening comprising an outer substantially cylindrical collar having an internal diameter slightly larger than that of said tube, a spider having a cylindrical rim portion of substantially the same internal diametervas that of said tube, a hollow hub mounted concentrically on said spider, a flame dellector plate disposed above said burner head and having a support rod mounted in said hub, and means mounting said spider coaxially Within said collar in such a position that the lower edge of the spider rim is axially spaced above the edge of said tube and the external wall of said spider rim is in concentric spaced relation from the internal wall of said collar, said burner head thus dening a central main opening and a concentric substantially annular opening therearound for retardation of a portion of the gaseous mixture passing through said burner head.

2. In a gaseous fuel burner, in combination with a duct of substantially constant cross-sectional area terminating in an upwardly facing opening and adapted for guiding a gaseous fuel and air mixture to the combustion zone of a furnace, a flame retention burner head secured to said duct over said opening comprising an outer substantially cylindrical collar having an internal diameter slightly larger than that of said duct, spacer means projecting radially inwardly from said collar over the top of said duct, and a spider mounted coaxially within said collar and having a central flame deflector mounting hub and a cylindrical rim portion of substantially the same internal diameter as that of said tube duct the lower edge of which rests on said spacer means so as to be axially spaced above the top edge of said duct and the external wall of which is in concentric spaced relation from the internal wall of said collar, said burner head thus defining a central main opening and a concentric substantially annular opening therearound for retardation of a portion of the gaseous mixture passing through said burner head.

3. In a gaseous fuel burner in combination with a con duit terminating in an exit port and adapted forV guiding a gaseous'Y fuel and airmixtureto thel combustion zone4 offa'furnace, a burner head mounted on' saidconduit at said' exit port comprising a collar having a portion adapted to'be mounted'on said conduit at said port'and definingl a channel oflarger cross-sectional'area than ysaid conduit, a spider having a rim portion of substantially'the same shape and size as said conduit and a central'hub coaxial therewith, means for supporting said` spider in axially` spaced relation above the'exit port ofsaid conduit and in'axially spacedrelati'on-within said'collar to define a main passage anda peripheral passagetherearound, and a flame deflector mounted on said spider hub'aboveand coaxial withl said passages;

4; Aame-retention-burnerheadadapted to be mountedover the' exit' port of a conduit'of a gaseous fuel burner for guiding'a gaseous fuel and air mixture to the combustion zone of a furnace comprisinga collar having a portion adaptedto'bemounted on theI conduit at the exit'port and defining achannel of larger cross-sectional area than that of the conduit, a spider having a rim portion of substantially the same size; shape and thicknessas-thelconduit and a central'hub coaxial therewith, andadapted to support a llame deflector above yand coaxial withtheburner head, and means for supporting said spider within said collar so as toibeIV in axially spaced relation'above-'the exit port of the conduit and in coaxially'spaced relation within said collar to divide theA channel defined by the collar into a main passage and a peripheral passage therearound.

5. A burner head for a gaseous fuelburner comprising aV gaseous mixtureconducting tube having an upwardly facing end, a collar fixed on said tube end and having a section of larger diameter than the tube and extending above the tube end, a tubular member having a downwardly facing end, said member. constituting a substantial'continuation of the tube end mounted-within said collar above said tube end and so radially spaced inwardly of the collar as to deiinean annular passage with the collar, at least a portion of said ends of said tube and said member being spaced apart to form passages connecting said annular passage and said tube, said annular passage being entirely unobstructed at its upper end and providing a relatively low velocity path for part of the fuel mixture for maintaining combustion of the fuel mixture emerging through the said member, and a central ame dellector support socket rigid with said tubular member.

6 The burner head defined in claim 5, wherein adjacent-portions of said tubular member and said collar have icoacting means determining their radial spacing to define said annular passage.

7. A burner head for gaseous fuel comprising a gaseous mixture conducting tube having an upwardly facing open end, a collar fixed on the tube end and having a section of larger diameter than the tube projecting above the tube end, and a spider mounted within said collar section having a rim disposed a short distance above the tube end in coaxial spaced relation with said collar section and a central hub for mounting a ame deector, the space between said rim and collar providing an annular fuel mixture passage surrounding the main fuel mixture passage through the spider.

8. A burner head for gaseous fuel comprising a gaseous mixture conducting tube having an upwardly facing open end, a collar fixed on the tube end and having a section of larger diameter than the tube projecting above the tube end, a spider having a rim constituting a substantial continuation of said tubemounted-onl -said 'collar/in 'axiallyS spaced'relationabovetheendotsaid tube and4 spaced inwardly of Vlthecollar'so as 'to defineean' annular passagejA therebetweengand means providing a' resilientlhub socketL for a' flame'deilectorsupport rod yon said-spiders 9. Aburner'headfor gaseous'fel comprising afgaseous mixture'conducting tube having Aan upwardly facing openJ end, a collar xedon thetube'end' andhaving'asection'- of'larger-diameter thanY thee tube projecting above-thel tubeend, a radially compressible and--expansible ytubularl element mountediwithin'said collarl in axially spaced relation to 'the tube" ende; means'ma-intaining said collar andtubular element lin substantially 'coaxially 'lixedlyA spaced'y relation so as to provide therebetween a substantiallyamnular low velocityfe'l mixture' passage; and a hub centrally mounted-onfsaiddtubular element formounting a flame deflecton support rod. f,

10. Af burner-head@ forgaseousfuel comprising a. gaseous mixture. conducting.;,tube; havingzanr upwardly facing open, end, a collar ixedon the tube yend and having;afsection1 offlarger'diameter thanthe tube projecting? above theftubezend,v a pluralityy of longitudinal ribs in-T ternally of lsaid collar-section,a'plurality.- of spacer ele-v ments on said collar extendingjinwardly above the :tube

4 end,v and:a=spiderisurrounded.by said collar having an expansible:andcontractible rimperipherally spaced from said: collar by said ip rojections and having its lower edge restingonsaidpacer elements, Aand a resilient ame rde-V ector. support rodunounting hubcentrally of saidspider.,

11. In thefburnenheaddefned in claim 10, saidhub. being'definedby spring armsnextending inwardly,y from. said 12. A burner head for gaseous fuel'burner comprisingl a gaseous mixture-conducting/tube' having an upwardlyE facingend, a. collar. fixedl onA said tube end and having a section off-larger` diameter than the tube and extending above the` tube end, a spider having a tubular peripheral portion constituting a substantial continuation of the tube end mounted vwithin-said collar above said tube end and so radially spaced inwardly ofthe collar as to define an annular passage-with the collar, said annular passage being in communication at its lower end with said tube and entirely unobstructed at its upper end and providing a relatively low velocity path for part of the fuel mixture for maintaining combustion of thefuel mixture emerging ,through saidfspider, a central ame deflector support socket on said spider, and coacting means on said spider and collar for determining their radial spacing to define said annular passage.

Referencesf Cited in the le of this patent UNITED STATES PATENTS 892,190 Sheppard et al. June 30, 1908 1,919,894V Lorimerv July 25, 1933 2,130,086 Hart Sept. 13, 1938 2,162,374I Chambers June 13, 1939 2,178,703! Robbins Nov. 7, 1939 2,183,836 Gordon Dec. 19, 1939 2,237,889" Rickert` Apr. 8, 1941 2,367,143 Schrader Ian'. 9, 1945 2,467,626 NormanI Apr.- 19, 1949 2,475,240 Hassmer'et al.' July 5, 1949 2,537,542 Norman' Jan. 9, 1951 2,541,315 West Feb. 13, 1951 2,541,433 Mueller Feb. 13, 1951 2,549,347 Van Tuyl Apr. 17, 1951 2,560,184- Norman July 10, 1951