US3182712A

US3182712A - Gaseous fuel burner for producing radiant heat

Info

Publication number: US3182712A
Application number: US235439A
Authority: US
Inventors: Zink John Smith; Robert D Reed
Original assignee: John Zink Co
Current assignee: Zinklahoma Inc
Priority date: 1962-11-05
Filing date: 1962-11-05
Publication date: 1965-05-11
Anticipated expiration: 1982-05-11

Description

May 11, 1965 J. 5. ZINK ETAL GASEOUS FUEL BURNER FOR PRODUCING RADIANT HEAT Filed Nov. 5, 1962 z Sheets-Sheet 1 JOHN SMITH ZI/VK ROBERT D. REED y 1965 J. 5. ZINK ETAL 3,182,712

GASEOUS FUEL BURNER FOR PRODUCING RADIANT HEAT Filed Nov. 5, 1962 2 Sheets-Sheet 2 INVENTORS JOHN SM/T H Zl/VK I? am 0. REED F/ 6. 5 BY Zarronwer United States Patent 3,182,712 GASEGUSFUEL BURNER FOR PRGDUCING RADIANT HEAT John Smith Zink and Robert D. Reed, Tulsa, Okla, assignors to .lohn Zink Company, Tulsa, Okla, 21 corporation of Delaware Filed Nov. 5, 1962, Ser. No. 235,439 3 Claims. (Cl. 158-116) The present invention relates to a burner for gaseous fuel and more specifically pertains to a burner assembly for discharging gaseous fuel over the face of a ceramic member to provide a high temperature source of radiant heat dispersed over a relatively large area of the face of the Wall of a furnace or a chamber to be fired. This application is a continuation-in-part of our application Serial No. 59,972, filed October- 3, 1960, now abandoned.

' It is known to provide for the discharge of a gaseous fuel from a plurality of discharge ports in directions which are parallel to the face of a refractory member to distribute the heat provided'by the burning fuel of over a substantial area of the ceramic member and such a burner assembly is disclosed in the Zink and Reed Patent 2,667,-

- 216. In the prior assembly ribs on the ceramic member intercept the flow of the gaseous fuel discharged from the burner head and .one purpose of the ribs is to slow down the movement of the gaseous .fuel after it escapes from the discharge ports in order to obtain stable combustion. The present invention pertions to a fuel burner assembly devoid of means for obstructing movement of the gaseous fuel after it is discharged from the burner head and stable combustion is attained by the shape and disposition of the'discharge ports which are in the form of elongated slots so that the gaseous fuel after escaping from the burner head loses velocity rapidly to provide for stable combustion and the slots are so disposed in relation to each other that there is co-mingling of the gas streams in areas closely adjacent the exit ends of the discharge ports to further promote stable burning.

An object of the invention is to provide a gas burner assembly wherein the gaseous fuel is discharged through a multitude of slots which are elongated in the direction of the axis of the burner head and so disposed as to provide for the discharge of one quantity of the gaseous fuel through one portion of each slot with respect to the quantity of the gaseous fuel escaping through another portion of each slot and to provide a burner head wherein the discharge slots are arranged to provide for changes in the directions at which gaseous fuel flows from the burner head in proceeding along the length of each slot.

Another object of the invention is to provide a burner head for gaseous fuel with a plurality of slots which are of elongated character measured downstream of the burner head and which are formed in an outwardly bulged wall so that the gaseous fuel which moves in a path which is normal to the surface from which it is discharged provides for the dispersion of the gaseous fuel escaping through the discharge slots in fan like patterns over the face of a refractory member.

A still further object of the invention is to provide a burner head with relatively narrow slots of elongated shape and in such a large number as to provide a large total discharge area for the fuel mixture and to provide slots of such structure as to prevent flashback from the combustion zone into the burner headeven when the gaseous fuel contains appreciable quantities of rapidly reacting gaseous fuels in a stoichiometric mixture with air. 1

Another object of the invention is to provide an up stream surface aon the burner head to develop radially outward components togthe gaseous fuel mixtureafter.

3,182,712 Patented May 11, 1965 it engages the upstream surface of the burner head to develop scrubbing of the associated portions of the burner head with the incoming cooling gaseous fuel to thereby prevent overheating of the downstream portions of the burner head.

A further object of the invention is to provide structure on the burner in the vicinity of the upstream ends of the discharge slots to promote a steady flow of the gaseous fuel through the ports adjacent the upstream ends.

Other objects and features of the invention will be appreciated by those skilled in the art pertaining to the combustion of gaseous fuels and as the present disclosure proceeds and upon consideration of the following detailed description taken in conjunction with the accompanying drawings wherein exemplary embodiments of the invention are disclosed.

In the drawings: 7 FIG. 1 is a plan view of a burner head exhibiting the invention shown in association with a ceramic member and a portion of the wall of a combustion chamber.

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

FIG. 3 is a sectional view of the burner head taken on the line 3-3 of FIG. 2 and showing a portion of the ceramic burner block.

FIG. 4 is a sectional view of a modified burner head taken on the line 4--4 of FIG. 5. a

FIG. 5 is a plan view of the burner head shown in FIG. 4 with a portion illustrated in section and taken on, the line 55 of FIG. 4.

The'invention pertains to a burner for discharging a gaseous fuel mixture in a substantially annular pattern about the burner head and along the face of a ceramic member to provide a relatively large area of radiant heat over the wall of a furnace chamber. A portion of a fire box wall 11 formed of refractory material is shown in FIG. 1 and this may constitute the floor of a chamber which is to be fired. A burner block 11 formed of suitable ceramic material desirably provides a part of the wall or floor of the furnace chamber. The block 11 may be of rectangular shape as shown in FIG. 1 and provided with a fiat face 12 (FIG. 2) mounted flush with the inner face of the refractory wall.

The burner block 11 is provided with a cylindrical shaped opening 14 for accommodating a portion of the burner head 16. The burner head formed of metal has a diameter which is slightly less than that of the opening 14. The downstream end of the burner head 16 is closed by a disc shaped wall 17 and it has a conical shaped upstream face 18. The apex 19 of the upstream face. is directed upstream of the burner and coincides with the axis of the burner head.

A conduit 21 forms a part of the burner head and provides means for guiding a gaseous fuel mixture towards the face 18 of the Wall 17 in the direction of the arrows 22. An annular wall 23 joins the downstream end of the conduit 21 with the perimeter of the discshaped wall 17. The diameter of the conduit 21 is smaller thanthat of the disc-shaped wall 17 but the wall 23 desirably has an arcuate or spherical shape and bulges outwardly as shown in FIG. 2. The burner is maintained in a centered position with respect to the opening 14 in the burner block by means of circumferentially spaced lugs 24 extending radially from the perimeter of the conduit 21.

g A unique feature of the burner head pertains to the shape and disposition of the discharge ports for the escape of the gaseous fuelmixture from the chamber 28 provided between the wall 17 and the annular bulged wall 23; The discharge ports are in the form of elongated slots 26. A multitude of slots 26 are provided in the wall 22 and in the embodiment illustrated there are more than forty of such slots spaced from each other around the circumference of the burner head. Each slot 26 extends from the downstream end portion of the conduit 21 to the upstream face 18 of the end wall 17. These elongated discharge slots 26 may be formed in any suitable manner and in one embodiment each slot 26 has a width of approximately 0.0 r inch. Each slot is long in relation to its width and in a typical embodiment each slot has a length of approximately one and one-half inches. Each discharge slot 26 may have an area of approximately 0.06 square inch. The wall 23 is relatively thick and may be secured to the conduit 21 by weldingas indicated at 27.

A supply of gas with air inspirated thereinto and mixed therewith in volume equal to or greater than theoretical is supplied under pressure into the conduit 21. The fuel mixture moves in the direction of the arrows 22 and encounters the face 18 of the wall 17. Pressure is thus built up adjacent the face 18 and the zone of highest pressure within the chamber 28 is indicated at A in FIG. 2. The pressures at B, C, D and E are progressively lower. If the pressure Within the burner head adjacent the zone E is but a few hundredths of an inch of water greater than the pressure externally of the burner head the pressure in the zone A is greater than one inch of water. The volume of the flow of the gaseous fuel mixture outwardly through any one of the discharge slots 26 varies with the square root of the pressure applied at the portal of the slot. Thus when the pressure in the zone A amounts to one inch of water and the pressure in the zone B is 0.10 inch of water the flow of the gaseous fuel through the zone A of each slot 26 will be 3.16 times greater than the flow through the portion E of each slot 26. The velocity of the discharge of the gaseous fuel mixture varies at the same ratio.

A relationship of velocities and pressures as hereinabove described, provides the advantageous result of dispersing the burning gaseous fuel over the face 12 of the ceramic block 11. The discharge of the fuel is in an annular pattern so that the dispersion of the burning gaseous fuel is over a large annular area of the block 11 and the wall and such a pattern is provided by the varying pressures at which the fuelis discharged. from the zones A to D. The flow from the zone B is relatively small in relation to the volume of fuel discharged through other portions of each slot 26. The relatively small volume of fuel mixture escaping in the zone B is influenced by the gaseous fuel escaping through that portion of each slot 26 downstream of the zone B so that the higher velocities in the zones D to A pull the fuel mixture escaping through the zone E forwardly to cause the fuel mixture escaping in the zone E to move outwardly along the downstream face 12 of the refractory block. a The arrows 31 associated with the zones A to D in FIG. 2 indicate the approximate direction of the flow of the gaseous fuel in the respective zones. It will be observed that the outward movement of the gaseous fuel as represented by the arrows 31 is in one general direction with portions of the fuel moving at slightly different directions but all of the escaping fuel converges upon the face 12 of the ceramic block. The gaseous fuel mixture escaping through each slot 26'tends to flow normal to the surface from which it is discharged and as a consequence of the arcuate. character of the outer surface of the wall 23 the fuel escaping through each slot 26 has a fan shape and is directed towards the facelZ of the ceramic block.

The ceramic body 11 is accordingly heated to provide a source of radiant heat and the burning fuel mixture is dispersed over a large area of the face 12. A high temperature is' developed over an annular area around the burner head and the high temperature is not confined to the zone immediately adjacent the burner head. The area of the face 12 may vary and the ceramic block 11 is d heated and adjacent portions of the wall 19 are also heated as a result of the gaseous fuel escaping from the zone A and some of the gaseous fuel mixture discharged in the zone B. The heat need not be confined to the block 11 and there may be some heating of the face of the wall 10.

The deceleration of the gas escaping through the slot 26 is such that it is not necessary to provide means obstructing the outward flow of the mass of gas. Stable burning is attained by the close proximity of the slots 26 to each other and in one embodiment they are spaced on one quarter inch centers. The fuel mixture escaping through the exit ends of the slots 26 co-mingle close to the exterior of the wall 23 and an ignition temperature is developed close to the perimeter of the burner head. The co-mingling of the fuel immediately after passing the exit ends of the slots 26 is a consequence of the low pressure in the adjacent streams while there is a normal pressure out-side the wall intermediate the slots 26. The action of co-mingling of the gaseous fuel and the quick ignition of the fuel develops an extraordinarily high temperature close to the perimeter of the burner head so that the flow as it is directed towards the ceramic block 11 causes the temperature thereof to rise to high levels in the annular area surrounding the burner head. The high temperature of the refractory material enhances the condition of radiant heat density immediately downstream of the refractory member.

The wall 23 is thick so that the length of the passage through each slot 26 in the direction of the arrows 31 is long in relation to the area of the discharge ports. It is this relationship which serves to prevent flashback from the combustion zone into the chamber 28. The length of the discharge passages measured in the direction of the arrows 31 is such as there is cooling action by the flow of the gaseous fuel mixture therethrough so that the burner head operate-s satisfactorily even when the fuel is a mixture of air with hydrogen, acetylene or ethylene because the flow passages are long enough to'produce the cooling efiFect required for these extremely actively chemically gases.

A modified head is shown in FIGS. 4 and 5 wherein the end wall 17a is provided with a conical surface 18a which is disposed at a smaller angle with respect to the axis of the burner head. The apex 19a of the conical surface is directed upstream of the burner head and is substantially aligned with the axis of the burner. The conical surface 18 and the conical surface 18a serve to deflect the gaseous fuel mixture radially outward from the axis of the burner head. The conical surface 18a may be disposed at an angle of approximately forty degrees with respect to the axis of the conduit 21 so as to effectively deflect the gaseous fuel radially outward and avoid any tendency of eddy currents being developed along the upstream surface of the end wall. The conical surface 18a is subjected to scrubbing by the cool gaseous fuel mixture whereby overheating of the end wall of the burner head is avoided. The downwstream portion of the burner head shown in FIGS. 4 and 5 operates at a temperature which is significantly lower than the operating temperature of the burner head shown in FIG. 1.

The burner head shown in FIGS. 4 and 5 includes a generally cylindrical shaped conduit portion 4-1 which may be welded to the conduit 21 as indicated at 27. The conduit portion or sleeve 41 has an outwardly flared annular surface 42 which merges smoothly with the inner surface of the bulged wall 23 so that the gaseous fuel mixture flows smoothly thereover and avoids the possibility of eddy currents being developed at the upstream ends of the discharge slots 26.

While the invention has been described with reference to specific structural characteristics and with regard to one burner head and a ceramic body it will be appreciated that changes may be made in the various elements as well as alteration in the overall assembly. ,Such modifications and others may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

What We claim and desire to secure by Letters Patent is: 1. A burner assembly for gaseous fuel comprising, ceramic means having a flat face throughout and in a single plane confronting a space to be fired, said ceramic means 7 under pressure from said conduit, said annular wall having a spherical shaped outer surface and having a plurality of elongated slots therein all extending in the direction of the axis of the burner head, said annular wall having a thickness ,of such magnitude with relation to the width of said slots as to prevent backfla'sh, upstream ends of said slots being positioned adjacent the face of said ceramic means and downstream of said face, and the downstream ends of said slots terminating adjacent the upstream face of said end wall.

2. A burner assembly for gaseous fuel comprising, ceramic means having a flat face in a single plane confronting a chamber to be fired, said ceramic means having an opening therethrough, a conduit of smaller cross section than said opening arranged therein, an end wallarranged transversely of and spaced from the downstream end of said conduit, the perimeter of said end wall projecting beyond the perimeter of said conduit, an annular wall joining the perimeter of said end Wall with the downstream end of said conduit providing a burner head with a chamber therewithin for receiving gaseous fuel under pressure from saidconduit, said annular wall having a convex shaped outer surface arching from said end Wall to said conduit, said annular wall having a plurality of elongated slots therein all extending in the direction of the axis of the burner head, a conical surface on said end Wall having its apex directed upstream of said burner head, said annular Wall having a thickness of such magnitude with relation to the Width of said slots as to prevent backfiash, up-

. stream ends of said slots being positioned adjacent the face of said ceramic means and downstream of said face, the downstream ends of said slots terminating adjacent the upstream face of said end wall, and said elongated slots being disposed adjacent each other measured circumferentially of said annular wall whereby the gaseous fuel escaping through the slots co-mingle close to the exterior of said annular Wall.

3. A burner assembly for gaseous fuel according to claim 2, wherein the apex of the conical surface is substantially in alignment with the axis of the burner head and the conical surface has a slope of approximately forty degrees with respect to the axis of the burner head.

References Cited by the Examiner UNITED STATES PATENTS 103,297 5/70 Burt 158116 X 194,561 8/77 Prentiss 158-68 1,393,547 10/21 Kotzebue 158-69 2,591,263 4/52 James et al. 158116 2,667,216 1/54 Zink et a1. 158-113 2,806,465 9/57 Hess. 2,870,829 1/59 Williams.

FOREIGN PATENTS 3 86,223 4/08 France.

570,248 1/24 France.

142,759 5/20 Great Britain.

JAMES W. WESTHAVER, Primary Examiner.

FREDERICK L. MATTESON, JR., PERCY L. PAT- RICK, Examiners

Claims

1. A BURNER ASSEMBLY FOR GASEOUS FUEL COMPRISING, CERAMIC MEANS HAVING A FLAT FACE THROUGHOUT AND IN A SINGLE PLANE CONFRONTING A SPACE TO BE FIRED, SAID CERAMIC MEANS HAVING AN OPENING THERETHROUGH, A CONDUIT OF SMALLER CROSS SECTION THAN SAID OPENING ARRANGED THEREIN, AN END WALL ARRANGED TRANSVERSELY OF AND SPACED FROM THE DOWNSTREAM END OF SAID CONDUIT, THE PERIMETER OF SAID END WALL PROJECTING BEYOND THE PERIMETER OF SAID CONDUIT, AN ANNULAR WALL JOINING THE PERIMETER OF SAID END WALL WITH THE DOWNSTREAM END OF SAID CONDUIT PROVIDING A BURNER HEAD WITH A CHAMBER THEREWITHIN FOR RECEIVING GASEOUS FUEL UNDER PRESSURE FROM SAID CONDUIT, SAID ANNULAR WALL HAVING A SPHERICAL SHAPED OUTER SURFACE AND HAVING A PLURALITY OF ELONGATED SLOTS THEREIN ALL EXTENDING IN THE DIRECTION OF THE AXIS OF THE BURNER HEAD, SAID ANNULAR WALL HAVING A THICKNESS OF SUCH MAGNITUDE WITH RELATION TO THE WIDTH OF SAID SLOTS AS TO PREVENT BACKFLASH, UPSTREAM ENDS OF SAID SLOTS BEING POSITIONED ADJACENT THE FACE OF SAID CERAMIC MEANS AND DOWNSTREAM OF SAID FACE, AND THE DOWNSTREAM ENDS OF SAID SLOTS TERMINATING ADJACENT THE UPSTREAM FACE OF SAID END WALL.