US3438718A

US3438718A - Industrial burner

Info

Publication number: US3438718A
Application number: US679344A
Authority: US
Inventors: Charles W Morck Jr
Original assignee: Selas Corp of America
Current assignee: Selas Corp of America; SELAS CORP
Priority date: 1967-10-31
Filing date: 1967-10-31
Publication date: 1969-04-15
Anticipated expiration: 1986-04-15

Description

United States Patent Ofiice 3,438,718 Patented Apr. 15, 1969 US. Cl. 431-158 6 Claims ABSTRACT OF THE DISCLOSURE A commercial burner of the internal combustion type constructed of sheet metal parts. A combustible mixture of fuel and air is injected radially into a substantially cylindrical combustion chamber from a multiplicity of points with the products of combustion being discharged through a slot in the side of the chamber.

SUMMARY OF THE INVENTION The present invention relates to industrial burners, and more particularly to a metal burner of high capacity, primarily for convection heating purposes.

In many heating applications it is desirable to use a metal burner, but for high temperature applications this has not always been possible. One of the main difficulties previously encountered has been the distortion of various parts of the burner due to differential expansion of the elements of which it is made. In addition, the heat of combustion has had the effect of eroding rapidly various of the metal parts.

It is an object of the invention to produce a high heat release burner constructed substantially entirely of metal.

It is a further object of the invention to produce a metal burner constructed in such a fashion that the various parts can move relative to each other without distortion as they expand and contract.

It is a further object of the invention to provide a burner having a slot through which hot products of combustion are released for heating purposes with the discharge of said products being substantially uniform as to temperature and velocity along the length of the slot.

The burner includes a substantially cylindrical co m bustion chamber having a slot in the side thereof through which products of combustion are discharged. A combustible mixture of fuel and air is supplied to this chamber through a plurality of openings around its surface to burn within the chamber. The elements of this chamber and its supporting parts are so constructed that they can move relative to each other, and they are cooled below the working temperature of the metal by the flow of the combustible mixture to the combustion chamber.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, its advantages and specific objects attained with its use, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a section through the burner taken on line 1-1 of FIG. 2, and

FIG. 2 is a section transversely of the burner taken on line 2-2 of FIG. 1.

DETAILED DESCRIPTION The burner includes a housing assembly and a combustion chamber assembly which are fastened together. The housing assembly has an outer shield 1 which is welded to end plates 2 to form, in effect, a plenum which is welded to a base plate 3. This-latter place is, preferably, rectangular in shape and is provided with a rectangular opening into which the combustion chamber assembly is moved. A curved baflle member 6 that is open at the ends and is provided with holes 7' through which the combustible mixture can flow is placed inside housing 1 and is attached to base plate 3 at the edges of the opening therein, as best shown in FIG. 2.

The combustion chamber assembly includes a mounting plate 8 which is also rectangular in shape and which is provided with a rectangular opening substantially the size of the outlet opening from the combustion chamber. This mounting plate has attached to its plates 9 forming the ends of the combustion chamber. Each of these plates is provided with a flange 111 that is bolted to the mounting plate 8 adjacent to the ends of the outlet slot by means of bolts 12. A suitable gasket is used in this connection. Each of the plates 9 is provided with an inner circular flange 13 extending toward the combustion chamber and an outer flange .14 extending in the same direction. The inner flange 13 receives in it a substantially circular refractory end plate 15 that forms the inner surface of the combustion chamber end.

The wall of the combustion chamber is comprised of one or more curved perforated sheets of metal, shown herein being three

sheets

16, 17, and 18. Each of these sheets can be about 6 /2" long and the number that is used will depend upon the length of the burner. The outer ends of the end sheets are received loosely in the groove formed between flanges 13 and 14 of the end plates 9.

Referring to FIG. 2 it will be seen that the outer edges of each sheet are bent backwardly to form flanges 19 which are held in position at the edges of the slot in plate 8 by a clamp 21 that is bolted to the plate. With this construction there is formed a substantially cylindrical combustion chamber having an elongated outlet 27 in its wall. Since the outer wall of the chamber comprises a plurality of sheets, the ends of the sheets are held in alignment by means of a refractory disc or partition 23 within the circle of the sheets and a clamp ring 24 encircling the ends of each sheet. Pins 25 extend through the clamp rings, between the ends of the sheets, into the discs in order to hold the parts in alignment. It is noted that the ends of the

sheets

16, 17, and 18 are slightly separated and that there is provided a compressible ring 26 of asbestos, or the like, between the ends of each sheet and end plates 9 to seal the joints. In addition, a suitable gasket is used between clamp ring 24 and the ends of the sheets. Thus, the various parts of the combustion chamber can move relative to each other as they are heated. The discs or partitions 23 have somewhat the effect of dividing the combustion chamber into a plurality of sections. In order to reduce any effect the discs will have on the discharge of products of combustion, they are tapered as shown at 33 to reduce the thickness of their lower edges immediately adjacent to outlet 27.

The outlet 27 of the combustion chamber is surrounded by a metal skirt formed of end pieces of sheet metal 28 and side pieces 29 as shown in the drawing. Clamp 30 holds the end pieces and the side pieces of the skirt in position on plate 8. This clamp member is held in position by bOlts 31. It is noted that the end pieces and the side pieces of the skirt are, preferably, individual pieces of metal and that the side pieces 29 can be made of a single piece of metal or of a plurality of pieces. In either event the side pieces and the flanges 19 are held in aligned position by pins 32 which extend, as best shown in FIG. 2, through the mounting plate 8 around the outlet opening. It is noted that the holes provided in flanges 19 and skirts 28 and 29 through which the pins 32 extend, are slightly larger than the pins so that it is possible for these pieces to move with respect to each other without buckling and changing shape.

The burner is ignited by a standard ignition device which may consist of a pair of electrodes across which a spark is jumped. This ignition device, indicated at 34, is held in position by a flange 35 to extend through an opening 36 in the right hand end plate 2. The inner end of this device extends through an opening provided in the end plate of the combustion chamber. The ignition device is sealed in the combustion chamber by means of a sealing plate 37 and a suitable gasket that are fastened to end plate 9. When a fuel mixture is supplied to the combustion chamber and the ignition device is operating, the mixture will be ignited and will flash through openings 38 in the partitions from one section of the combustion chamber to the next. Ignition of the burner is detected by a conventional ignition detection device, which may be of the ultra-violet type, that is mounted in a plate 41 attached to the left hand end plate 2 of the housing. This detection device extends through plate 15 at the end of the combustion chamber and is sealed with respect to the opening through which it extends by means of a plate 42 and a suitable gasket. It will be noted that the openings 38 in the partitions are not aligned with the axes of the ignition device and the detection device so that the detection device can only respond when flame has flashed through all of the sections.

The combustion chamber assembly is moved into the housing assembly and held in position therein by suitable bolts extending through mounting plate 3 and base plate 8. It will be seen that the entire structure with the exception of end plates 15 and partitions 23 are made of individual pieces of sheet metal which can easily be formed and fastened together. The end plates 15 and partitions 23 can be made of some high temperature refractory metal or they can be made of a ceramic that will not spall or crumble at the temperatures encountered. The connection between each of the parts under heat is such that they can move relative to each other to prevent distortion or buckling thereof as the burner is operated.

When in operation, the burner can be supported either by flange 5 on the inlet or by attaching mounting plate 8 to a suitable support. A combustible mixture of fuel and air under pressure is supplied through inlet 4 to the plenum chamber formed between housing 1 and the exterior of the combustion chamber. Baffle 6 serves to break up the mixture so that it flows evenly through openings 43 of the chamber wall into each section of the combustion chamber entirely around its periphery, except for outlet 27. Openings 43 are so formed that the jets of mixture are discharged radially inward and meet substantially at the axis of the chamber. Thus, there is created substantial turbulence that results in rapid combustion. The hot products of combustion flow in an even sheet of substantially uniform temperature and velocity through outlet 27 for the purpose of heating an object or space.

In actual operation a burner having an outlet opening inches in length and 1%" wide was operated on a natural gas-air mixture at 6 pounds per square inch guage at the rate of over 230,000 B.t.u. per hour per inch of opening. At this rate of burning none of the metal parts was heated above use limits of the materials employed and, although there was some shifting due to diiferential expansion, no bending or distortion of the various parts occurred. The burner has a turndown ratio of over 8 to 1,

and at all rates of operation the uniformity of the temperature and velocity of the sheet of hot products of combustion discharged through the outlet was well within acceptable limits.

While in accordance with the provisions of the statutes I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit and scope of the invention set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

What is claimed is:

1. In apparatus to produce hot combustion gases, the combination of means forming a substantially cylindrical combustion chamber having a wall and ends, said wall being provided with an axially extending elongated outlet and a plurality of perforations extending around and along said wall, means to join said ends to said wall loosely, means to seal said joints, a plate attached to said walls and ends around said outlet, a casing surrounding said combustion chamber and attached to said plate around said outlet, the space between said casing and Wall forming a plenum, means to supply a fuel air mixture to said plenum to flow radially through the openings in said wall to said combustion chamber to be burned therein, the products of combustion being discharged through said opening.

2. The combination of claim 1 in which said wall is composed of a plurality of perforated sheets of metal bent to substantially cylindrical shape with the ends thereof slightly separated and the edges thereof forming the edges of said opening, and means to hold said separated ends in alignment and close the space between them.

3. The combination of claim 2 in which said means to hold said ends in alignment includes a partition across said combustion chamber which is thicker than the space between said ends, said partition being provided with an opening to connect the portions of the combustion chamber on opposite sides thereof.

4. The combination of claim 3 in which said partition is reduced in thickness at said outlet.

5. The combination of claim 1 in which one of said ends is provided with an opening, an ignition device extending into said chamber through said opening, a combustion responsive device, and means to mount said combustion responsive device in the other of said ends.

6. The combination of claim 1 in which there is provided a diffuser member in said plenum, said diffuser member extending between said means to supply and said wall of said chamber.

References Cited UNITED STATES PATENTS 2,591,283 4/1952 Nesbitt et a1 431158 3,251,394 5/1966 Thorpe et al 431--158 FREDERICK I. MATTESON, JR., Primary Examiner.

EDWARD G. FAVORS, Assistant Examiner.

U.S. Cl. X.R. 239-265. 1 1