US3416735A

US3416735A - Burner assembly producing radiant heat

Info

Publication number: US3416735A
Application number: US631842A
Authority: US
Inventors: Robert D Reed
Original assignee: John Zink Co
Current assignee: Zinklahoma Inc
Priority date: 1967-04-18
Filing date: 1967-04-18
Publication date: 1968-12-17
Anticipated expiration: 1985-12-17

Description

Dec. 17, 1968 REED BURNER ASSEMBLY PRODUCING RADIANT HEAT 2 Sheets-Sheet 1 Original Filed June 12, 1963 FIG.

FIG. 2.

fl n INVENTQR Robert D. Reed ATTORNEY Dec. 17, 1968 REED BURNER ASSEMBLY PRODUCING RADIANT HEAT 2 Sheets-Sheet 2 Uriginal Filed June 12, 1963 FIG. 6.

FIG. '7.

ZNVENTOR Robert D. Reed ATTORNEY United States Patent 3,416,735 BURNER ASSEMBLY PRODUCING RADIANT HEAT Robert D. Reed, Tulsa, Okla, assignor to John Zink Company, Tulsa, Okla, a corporation of Delaware Continuation of application Ser. No. 287,233, June 12,

1963. This application Apr. 18, 1967, Ser. No. 631,842

The portion of the term of the patent subsequent to May 11, 1982, has been disclaimed 2 Claims. (Ci. 239--567) ABSTRACT OF THE DISCLOSURE A burner assembly for producing radiant heat by discharging the gaseous fuel at an angle towards the surface of a ceramic member fro-m which the heat radiates onto objects to be heated.

This application is a continuation of my copending application, Ser. No. 287,233 filed June 12, 1963 now abandoned.

The present invention relates to a fuel burner in association with a ceramic body for the dispersion of the heat over a relatively large area of the face of the ceramic body and the invention more specifically pertains to a burner assembly for discharging a gaseous fuel mixture in directions generally radially outwardly from a burner head and towards the face of a ceramic body to provide heating apparatus which provides improvements in the dispersion of heat and improvements in the stabilization of the burning fuel and improved dissipation of heat from the burner head and improvements in the delivery of heat substantially uniformly to the surface of the ceramic body.

It is known to provide for the discharge of a gaseous fuel mixture in directions generally radially from a burner head and substantially parallel to and along the face of a ceramic member. In one prior device the ceramic member is provided with ribs which are engaged by the burning fuel to provide turbulence and dispersion of the burning fuel and the hot products of combustion. Such prior apparatus while satisfactory in service tends to provide striation of the heat on the surface of the ceramic member and the stability of burning throughout extreme ranges of the designed heat release is not as good as desired for critical service. The burner head of the prior assembly also attains a relatively high temperature promoting deterioration of the burner tip. The ribs and the discharge port arrangement of the prior device tend to develop a non-uniform heat pattern on the face of the ceramic body.

It is an object of the present invention to provide improvements in an assembly for producing radiant heat from the face of a ceramic member wherein the heat is developed along a convex face on the ceramic body which serves to disperse the radiant heat over an enlarged area forwardly of the burner assembly.

Another object of the invention is to provide a burner assembly wherein the gaseous fuel mixture is discharged from the burner head into impact engagement with the face of the ceramic member to promote stability of the burning of the fuel and to provide discharge ports which provide for the intermingling of the fuel in an annular zone closely adjacent the perimeter of the burner head to further promote stability in the burning of the fuel whereby plural means are provided for the stabilization of the burner throughout a wide range of heat release.

A further object of the invention is to provide a burner head for the assembly designed to promote dissipation of heat from the structure of the burner tip by providing for impact of the cool gaseous fuel mixture against downstream surface portions of the burner tip and structure which promotes acceleration of the fuel mixture along downstream portions of the burner head to scrub heat therefrom and with the discharge ports so formed as to avoid partial burning of the fuel inside the burner head and provide a burner head which operates at or below temperatures eight hundred degrees Fahrenheit under normal furnace conditions.

Another object of the invention is to provide a burner head with discharge ports so that the fuel steams escaping through the exit ends of the discharge ports merge closely adjacent the perimeter of the burner head and to direct the fuel escaping from the burner head along the surface of a ceramic body and into contact with the surface thereof whereby the lower pressure zone in the moving fuel in contact with the surface causes the gaseous materials to cling to the surface of the ceramic body even through changes in the contour of the surface thereof to heat the surface of the ceramic body substantially uniformly throughout a large annular zone surrounding the burner head.

Other objects and features of the invention will be appreciated and become apparent to those skilled in the art to which the invention pertains as the present disclosure proceeds and upon consideration of the following detailed description taken in conjunction with the annexed drawings wherein an exemplary embodiment of the invention is disclosed.

In the drawings:

FIG. 1 is an elevational view of a burner assembly embodying the invention illustrated in association with a furnace wall.

FIG. 2 is a sectional view taken on the line 2-2 of FIG. 1.

FIG. 3 is a sectional view of the burner head illustrating a portion of the ceramic member.

FIG. 4 is a fragmentary section taken on the line 44 of FIG. 3.

FIG. 5 is a fragmentary sectional view on a larger scale illustrating the spacing and disposition of the discharge ports and taken on the line 5-5 of FIG. 3.

FIG. 6 is a diagrammatic view of the face of the burner assembly illustrating the uniform distribution of heat over the face of the ceramic body.

FIG. 7 is an elevational view on a smaller scale illustrating the manner in which burner assemblies embodying the invention may be mounted on the wall of a furnace.

The invention pertains to a burner in combination with a ceramic body or tile represented at 10 in FIG. 1 which is adapted to be mounted in and form a part of the inner face of a furnace wall 11. The ceramic body 10 may be in the form of a slab shaped member and while the perimeter is represented as having a rectangular formation the boundary may have any desired shape for convenience in mounting it in a furnace wall. The ceramic member 10 has an inner face 12 which is in general flush with the inner surface of the furnace wall 11.

A feature of the invention pertains to the shape of the face 12 which is of arcuate formation and of convex shape and preferably forms a segment or a parabolic curve as best shown in FIG. 2. The ceramic body 10 is provided with a central opening 14 in which a burner head 16 is accommodated and the arcuate surface 12 retreats outwardly of the furnace chamber in proceeding in radial directions from the opening 14. The major portion of the inner face of the ceramic body 10 is of convex shape which serves to disperse heat radiating from the ceramic member and this feature will be further appreciated as the disclosure proceeds.

The burner head 16 for gaseous fuel is supported in the opening 14 and lugs 17 maintain the burner head 16 in a centered position therein. A gaseous fuel mixture is supplied into the burner head through a conduit 18. The

burner head 16 is generally of tubular formation and the downstream end is obstructed by means of a closure member 21 as best shown in FIG. 3. The closure member is desirably formed as a separate element and provided with fillets 20 to position the closure member in proper relationship with an outwardly flared downstream end portion of the tubular structure of the burner head 16. The closure member 21 may be secured to the flared end of the tubular portion by welding as indicated at 22. A cavity is provided in the portion of the closure member facing the furnace interior and a pronounced conical surface 23 forms the upstream face portion of the closure member. The apex portion 26 of the closure member substantially coincides with the axis of the burner head and serves to divert the gaseous fuel mixture entering the burner head from the conduit 18. The fuel mixture accelerates along the conical surface 23 to carry heat from the closure member and for the further purpose of diverting the gaseous fuel mixture to positions for escape through discharge ports 24.

While the discharge ports may be of any desired shape they advantageously take the form of elongated slots 24 as shown in FIGS. 2 and 3. The discharge slots 24 are formed in the outwardly flared portion of the tubular shaped burner head 16 and may be formed in milling operation. The outer annular surface 27 of the flared portion of the burner head provides a concave surface which defines the exit ends of the discharge slots 24. The inner face 30 of the flared portion provides an annular convex surface which defines the entrance ends of the discharge slots 24. The gaseous fuel mixture escaping from the discharge ports 24 moves in the directions of the arrows and the reuslting direction of the gaseous fuel mixture is represented by the arrow 29. The escaping fuel mixture thus moves in a direction to impact the face 12 of the ceramic body 10.

The width of each discharge slots 24 may vary but should not exceed 0.045 inch. There is a large number of discharge slots 24 as will be appreciated from a consideration of FIG. 5 and the discharge slots are equally spaced about the periphery of the burner head. In one embodiment the circumferential spacing of the discharge ports 24 is on one quarter inch centers and at 0.205 inch from the edge of one slot to the adjacent edge of the next adjacent slot. The discharge slots 24 have a length of about one and a quarter inches so that the length-width ratio of the slots is in the neighborhood of 27.7 to avoid flashback of the burning fuel into the burner head.

The gaseous fuel mixture as it escapes from the exit ends of the discharge slots 24 moves in the directions of the arrows 25 (FIG. 3). The direction of flow of the escaping gaseous fuel mixture is at right angles to the surface at the point or zone therealong where the flow initiates. The convergent energies within a stream cause it to widen in directions transversely to the plane of the slot 24. The gaseous fuel streams escaping through the exit ends of the discharge ports 24 merge and the expansion angle of the fuel streams is greater than the divergent angles of the slots 24 as will be appreciated from a consideration of FIG. 5. The merger of the fuel streams is close to the perimeter of the burner head and approximately at the annnlar band 31 (FIG. 6). Such merging promotes stability of burning of the fuel which taken with the impacting of the fuel on the surface 12 provides plural means serving to stabilize the flame throughout a wide range of operating conditions involving changes in the volume of the fuel mixture.

The merging of the fuel streams in an annular zone closely adjacent the perimeter of the burner head provides a further advantage and serves to develop a substantially uniform temperature throughout the annular area between the ban-d 31 and the band 32 (FIG. 6) which represents the outer limits of the heating of the face of the tile. The ceramic body 10 may be provided with bosses 41 which may be formed integral therewith and project from the surface 12. The bosses serve to enhance radiant dissipation through the addition of areas to the surface of the tile. The bosses 41 are aerodynamica-lly shaped to produce a gas flow pattern as depicted in FIG. 1 for the delivery of the heat to the side edge surfaces of the bosses. The inner ends of the bosses 41 are of wider shape than the outer ends as shown in FIG. 1.

In operation and when the gaseous fuel mixture is supplied under pressure into the burner head 16 the fuel escapes through the discharge slots 24 and moves along the arcuate surface 12 of the ceramic body 10. This surface radiates heat evenly and in view of the fact that the surface 12 is convex the dispersion is radiated throughout a greater are than the radiation taking place if the surface 12 was flat. The discharge of the gaseous fuel through the large number of discharge slots 24 serve to produce substantially uniform heat values along all circumferential portions of the surface 12 of the ceramic body 10 and substantially uniform temperatures along the surface between the

annular bands

31 and 32.

The bosses 41 which constitute auxiliary elements further enhance the dissipation of the radiant heat through the addition of area to the face 12 of the ceramic body 10. The side edges of the bosses 41 are disposed at approximately ninety degrees to the surface 12 and thus dissipate radiant energy at low angles. The aerodynamic shape of the bosses facilitates the flow pattern as shown in FIG. 1 for the delivery of heat to the side edges of the bosses 41.

A burner assembly may be mounted in the wall of a furnace or several may be employed as shown in FIG. 7 and in patterns which need not be symmetrical. The ceramic bodies 10 are heated and there is delivery of heat from the ceramic bodies 10 to adjacent portions of the furnace wall 11. This delivery of heat varies in accordance with the fourth power of the absolute temperature differential between the hot ceramic bodies 10 and the colder portions of the furnace wall 11. Thus substantial quantities of heat are delivered to the furnace wall for radiation therefrom.

The burner assembly is stable in operation and burning of the fuel is maintained when turned down to ten percent of the designed heat release and through a range of one hundred percent of the designed heat release. Stable burning is maintained by impact of the gaseous fuel streams with the face 12 of the ceramic body 10 and as a consequence of merging of the gas streams soon after escape from the exit ends of the discharge ports 24.

The assembly provides for improved dissipation of heat from the structure ,of the burner tip. The cool gaseous fuel mixture enters the burner head 16 and impacts against the conical surface 23. There is acceleration of the fuel mixture along this conical surface which serves to carry heat away from the burner head and particularly the closure member 21. In operation the temperature of the closure member does not exceed seven hundred and fifty degrees Fahrenheit in an average operating condition. The relatively long and narrow discharge slots 24 provide a high ratio of length to width to prevent flashback for the burning fuel and thus avoids partial burning of the fuel within the burner head. These features promote cooler operation of the burner head.

The close proximity of the discharge slots 24 to each other and their disposition which provides that the fuel streams merge closely adjacent the perimeter of the burner head 16 assures an even delivery of heat to all circumferential portions of the ceramic body 10. As the gaseous materials move along and in contact with the convex face 12 the lower pressure zone in the moving gaseous medium in contact with the surface 12 causes the gaseous materials to cling to the face 12 even though there is a significant change in the contour as formed by the convex character of the face 12. Thus the gases cling to the arcuate face 12 to heat the surface of the ceramic body 10 evenly and uniformly.

While the invention has been described with reference to specific structural features and characteristics it Will be appreciated that changes may be made in the elements as well as the overall organization. The perimeter of the ceramic body need not be of rectangular formation and such changes and others may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

What I claim and desire to secure by Letters Patent is:

1. A burner head for firing onto the surface of a ceramic member to produce radiant heat comprising, a tubular member, a downstream end portion on said tubular member flaring outwardly from the axis of said member in proceeding to the downstream end thereof, said end portion having an outer annular surface of concave shape viewed in side elevation, said end portion having an inner annular surface of convex shape opposite said concave surface, a closure member obstructing the downstream end of said end portion, a conical surface forming the upstream face of said closure member with the apex thereof substantially coinciding with the axis of said tubular member, said end portion having a plurality of circumferentially spaced elongated discharge slots therein throughout the circumference of said tubular member with their outlets defined by said concave surface, said slots being disposed with their lengths substantially parallel to each other and substantially parallel to the axis of the tubular member and the portals of said slots being defined by said convex surface which arches inwardly from a line intersecting opposite ends of a slot in proceeding from one end of the same slot to the midportion of the same slot and thereafter arches towards said line in proceeding to the other end of the same slot, means for guiding a gaseous fuel into said tubular member and into said end portion for engaging said conical surface which diverts the gases towards said convex surface whereby the gaseous fuel escaping through said discharge slots flows from said arched convex surface and the gaseous fuel escaping through opposite ends of each discharge slot converges towards the gaseous fuel escaping through the intermediate portion of the same slot, and said discharge slots diverging from each other in proceeding radially from the axis of the tubular member at angles less than the divergent angle of the fuel streams escaping therethrough.

2. A burner head according to claim 1 wherein the discharge slots are circumferentially spaced from each other by no more than one-quarter of an inch.

References Cited UNITED STATES PATENTS 94,103 8/1869 Gill 239-597 XR 1,043,396 11/1912 Buddington 239-597 1,573,749 2/1926 Ross 239-567 XR 3,139,138 6/1964 Bloom 158-11 3,182,712 5/1965 Zink et al. 158-113 FREDERICK L. MATTESON, JR., Primary Examiner.

HARRY B. RAMEY, Assistant Examiner.

US. Cl. XtR.