US3285317A

US3285317A - Multi-port gas burner

Info

Publication number: US3285317A
Application number: US314996A
Authority: US
Inventors: Jr Louis P Hine; Richard J Vales
Original assignee: CA Olsen Manufacturing Co
Current assignee: YORK-LUXAIRE Inc A CORP OF DE; CA Olsen Manufacturing Co
Priority date: 1963-10-09
Filing date: 1963-10-09
Publication date: 1966-11-15
Anticipated expiration: 1983-11-15

Description

Nov. 15, 1966 1.. P. HINE, JR, ETAL MULTI-PORT GAS BURNER 2 Sheets-Sheet 1 Filed Oct. 9, 1963 INVENTORS.

Louis P. Hines dr.

BY Richard J. Vales flm; m y

ATTORNEYS.

Nov. 15, 1966 Filed Oct. 9, 1965 L. P. HINE, JR., ETAL 3,285,317

MULTI-PORT GAS BURNER 2 Sheets-Sheet 2 Fig. 6

INVENTORS Lou/5 P. Hwss J2. BY PLCHAED J. VALES ATTORNEY United States Patent 3,285,317 MULTI-PORT GAS BURNER Louis P. Hine, Jr., and Richard J. Vales, Elyria, Ohio, assignors to The C. A. Olsen Mfg. Company, Elyria, Ohio, a corporation Filed Oct. 9, 1963, Ser. No. 314,996 8 Claims. (Cl. 158-99) This application is a continuation-in-part of application Serial No. 155,015, filed November 27, 1961, and now Patent No. 3,177,923.

This invention relates to gas heating and particularly to gas burners for furnaces.

It is an object of the invention to obtain increased efliciency and improved characteristics of combustion of fuel gases.

A further object is to avoid tendency for flash-back.

Still another object is to overcome a tendency for resonance or noise. I

Still another object of the invention'is the incineration of entrained lint, the prevention of clogging of gas burners, and simplification and reduction of costs of construction of durable, sturdy gas burners of light weight, which are safe in operation.

Still another object is to provide a universal burner suitable for any type of gas.

Other and further objects, features and advantages of the invention will become apparent as the description proceeds.

In carrying out the invention in accordance with a preferred form thereof, an elongated horizontal burner is provided which is fabricated from sheet material such as carbon steel or other cold rolled steel to form a mixing tube tapering to a relatively small closed end with an open top closed by burner strip having elongated slots therein. The slots or ports are arranged in parallel rows lengthwise along the burner strip and there are at least three rows of such elongated ports or slots. The burner strip is dished or formed concave so that the center ports are lower than the side ports and resonance of the flames is avoided by the difference in height of the flames at the center and side ports. The ports near the gas inlet end of the mixing tube are made narrower to minimize tendency for flashback.

Preferably the burner strip is composed of materials such as chrome type stainless steel, which is not corroded by sulphur-containing gases and withstands high temperatures, permitting use as a universal burner for any type gas. The slots are relatively long, but of considerably less length than the extent of the mixing tube so as to provide enough webs, or material between successive slots in the same row, for adequate structural strength. The use of non-corrosive strip material prevents alteration of slot size or contour in event of contact with corrosive gas.

The burner strip is composed of relatively thin gage stock so as to maintain a relatively high temperature on the inner surface of the burner strip. Nevertheless, there is a high temperature difference between the slots and the edge of the strip so that the mixing tube runs cool. The slots are as narrow or narrower than the thickness of the burner strip and the flashback tendency is in this manner further diminished even for relatively fast flame propagation gases such as manufactured gas and propane gas.

In operation any lint .in the atmosphere is entrained in the column of mixed air and combustible gas traveling lengthwise in the mixer tube. The burner strip forms a zone of high temperature difference between slot edges and mixer tube, incinerating lint carried upwardly toward the slots from the column and the streams of mixed air and gas. Ignition of the air and gas mixture on the outer side of the zone formed by the burner strip produces in= cinerating temperature on the inner side so that the lint is incinerated, leaving only light ash which can travel through the port without clogging. A better understanding of the invention will be afforded by the following detailed description considered in conjunction with the accompanying drawing in which:

FIG. 1 is an elevation of a furnace burner forming an embodiment of the invention.

FIG. 2 is a plan view of the burner of FIG. 1.

FIG. 3 is a view of a cross-section of the burner of FIGS. 1 and 2 cut by a plane 33 represented in FIG. 1.

FIG. 4 is a view of a section of the burner of FIG. 1 cut by a plane 44 passing through the narrower portion of the mixing tube, the plane 44 being indicated in FIG. 1.

FIG. 5 is an end view of the burner of FIG. 1 showing the arrangement of the air mixture control valve.

FIG. 6 is a fragmentary view to an enlarged scale of the burner of FIG. 2 showing variation in slot Width exaggerated.

Like reference characters are utilized throughout the drawing to designate like parts.

The burner comprises a mixing tube 11 having a relatively small closed end 12 and an open end 13 with a venturi throat 14. The open end 13 has a relatively large diameter to receive a conventional rotatable-diaphram type of shutter 15 for controlling the ratio of air to gas in the mixture admitted in the mixing tube 11. The shutter 15 has conventional center opening 16 into which the nipple of a gas pipe (not shown) projects.

The diameter of the mixing tube 11 increases from the venturi throat portion 14 to a point 17 of maximum diameter, after which it again tapers to a relatively small diameter at the end 12. As shown in FIG. 3, the portion of the mixing tube 11 between the maximum diameter point 17 and the end 12 has a longitudinally extending lateral opening 18 covered by a strip 19. Long, narrow slots 20 in a plurality of rows, at least three, are provided in the burner strip 19 to form ports from which separate streams of air-gas mixture issue to form a flame.

Preferably the portion of the material forming the tube 11 adjacent the lateral opening 18 is bent transversely outward to form ribs 22 for spacing the burner strip 19 from the remainder of the mixing tube 11. The burner strip 19 is joined to the edge of the ribs 22 in any suitable manner to form a gas-tight joint. Preferably, the edges 23 of the ribs are bent transversely, sloping slightly upward, and the edges 24 of the burner strip 19 are crimped around the edge portions 23.

and gas flowing upwardly from the column of mixed air I The burner strip 19 is dished or made concave so that the center slots are lower than the outer slots or ports and any tendency for the issuing gas or flame to form resonating columns and to produce obnoxious noise or to sing is avoided by the interference between vibration of any air columns or gas columns at the center ports and the side ports. These columns are of diflerent lengths because the center ports are lower. Therefore, resonance is prevented. To facilitate assembly and formation of tight joints at the ends of the strip 19, the ends may be partially or wholly flattened.

In order to achieve low manufacturing costs, durability and lightness, the mixing tube 11 is preferably fabricated from two pieces of sheet material such as

pieces

25 and 26 composed of cold rolled, carbon-steel sheet. The

pieces

25 and 26 are stamped or pressed to shape to provide a frusto-conical, or circular-cross section, cavity 31 in the central portion of the two

sheets

25 and 26 to form the hollow mixing tube interior with flat side portions 27 and clogging does not occur.

3 28 and with the ribs 22. The end 12 is closed. The

flattened portions

27 and 28 are joined in any suitable manner as by means of crimped over edges 23.

In the embodiment illustrated the slots 20 consist of three rows of slots, each row consisting of 17 slots in alignment.

For guarding against flash-back even with fast burning gases with a high rate of flame propagation such as manufactured gas having high percentage of hydrogen, the slots 20 are made narrow, being no wider than the thickness of the strip 19, preferably slightly less. As shown in the drawing, the thickness of the strip is the depth of the slots and the width of the slots is no greater than their depth. As a further safeguard, the slots 21 at the manifold or inlet end of the burner strip 19 are made slightly narrower than those in the central portion with the slot width becoming progressively narrower toward the manifold end or the inlet end at which the shutter 15 is located.

The invention is not limited to specific dimensions, but in the form of gas burner for furnaces forming a specific embodiment illustrated the slots 20 are approximately of an inch in length with approximately /8 inch spacing between successive slots in each row and with approximately %2 inches between adjacent edges of the slots in adjacent rows. The distance of the center portion of the burner strip 19 below the side edges of the burner strip is approximately the width of the burner strip and the slots 20 occupy approximately to /3 of the width of the burner strip 19.

Where the burner strip 19 is made of 20 gage stainless steel strip the ports are approximately of an inch wide in the central portion of the burner and the width is decreased to approximately of an inch at the end near the manifold, which is approximately ten percent less. In practice, in order to balance the port plates or burner strips, they are made with narrower ports or orifices at each end so that they are symmetrical and there is no danger of an error being made by mounting the strip in the wrong direction.

For structural strength and also for correct thermal balance, the maximum feasible length of slot and minimum web or spacing between successive slots in the same row depends upon slot arrangement and strip thickness. To avoid distortion of slot width we believe that thinner strips will require shorter slots, and greater web dimension than thicker strips. Generally, the optimum slot length is or more times the slot width for most eflicient operation.

The sheet material comprising the

pieces

25 and 26 is smooth surfaced and preferably coated with a smooth lacquer or other coating material. Consequently, lint drawn into the openings of the shutter assembly from the air tends not to adhere to the inner surfaces of the mixing tube 11 and a clogging of the interior does not occur. However, lint tends to be drawn to the ports in the burner strip 19. As will be explained more fully hereinafter, the lint is incinerated at the ports and port When the ports are punched, they may be punched from the inner surface of the strip toward the outer surface in order to avoid forming a burr on the inner surface which might catch lint or arrest its progress through the port opening and to the point of maximum temperature for disintegration.

The burner strip 19 is composedof very thin material, as described, so that the inner surface runs substantially as hot as the outer surface as a result of the flames issuing from the ports 21. Moreover, the material of which the low or lower as that of the carbon steel tube 11 so that there is a high temperature gradient between the slots or ports 20 and the edges 24 of the burner strip 19. Thus, the tube 11 runs relatively cool, notwithstanding the high temperature of the slot portion of the burner strip 19 at the base of the flame.

A suitable material for the burner strip 19 has been found to be stainless steel particularly the chromium type of stainless steel which is not corroded when exposed to sulphur-bearing gases and will withstand higher temperature than carbon steel without explosion of the metal. This is especially important when low pressure or bottled gas or manufactured gas is used which may have a flame temperature of about 1200 F., not far from the critical temperature for carbon steel. Heat resisting steel, moreover, minimizes grain growth and therefor minimizes permanent deformation. It also has a somewhat lower conductivity than carbon steel. In the embodiment illustrated, the burner strip 19 is composed of 20 gage stainless steel, which is approximately .035 inch in thickness. Such thin strip runs very hot at the lower surface immediately adjacent the slot 20 and causes incineration of any lint drawn to the slot 20.

We have found that with three rows of ports the flame is brought down close to the ports to increase the temperature of the burner strip and obtain satisfactory consumption of lint. The arrangement permits delivering suflicient gas to generate 25,000 B.t.u.s an hour for each square inch of port area without blowing the flame away from port as well as permitting greatly reduced gas delivery without flash-back.

In order to permit use of one pilot burner for several adjacent burners, each burner may be provided with a carry-over slot 35 which overhangs a port for transferring flame to an adjacent burner to ignite it.

While the invention has been described as embodied in concrete form and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that the invention is not limited thereto, since various modifications will suggest themselves to those skilled in the art without departing from the spirit of the invention.

What is claimed is:

.1. A gas burner comprising a mixing tube having a gas inlet opening and a longitudinal outlet opening, and a burner strip across said outlet opening composed of sheet material and having elongated parallel slots therein no wider than the depth of the slots, the slots being approximately ten percent narrower at the end near the gas inlet opening and of such an order of magnitude as ordinarily to preclude flash back.

2. A gas burner comprising a mixing tube extending longitudinally, closed at one end and having an inlet opening at the other end for admitting gas and a longitudinal outlet opening extending lengthwise along the side of the tube, and a burner strip across said outlet opening composed of sheet material and having elongated parallel slots therein no wider than the depth of the slots, said slots being approximately ten percent narrower toward the gas inlet opening and of such an order of magnitude as ordinarily to preclude flash back.

3. A gas burner comprising a mixing tube extending longitudinally, closed at one end and having an inlet opening at the other end for admitting gas and a longitudinal outlet opening extending lengthwise along the side of the tube, and a burner strip across said outlet opening having elongated parallel slots therein, the slots being of the order of of an inch across in the central portion of the mixing tube and of the order of 1 of an inch across at the gas inlet opening end of the mixing tube.

4. A gas burner comprising a frusto-conical mixing tube extending longitudinally between a closed end and a second end having a gas inlet opening and having a longitudinal outlet opening extending along the side of the tube, and a burner strip across said outlet opening having elongated parallel slots therein extending lengthwise of the mixing tube, said strip being concave to lower the central slots below the side slots of the burner strip sufliciently to change the length ofthe air column at the central slots, the slots being approximately ten percent narrower at the end near the gas inlet opening and of such an order 0 magnitude as ordinarily to preclude flash back.

5. A burner as in claim 4 wherein the burner strip is dished to the extent of about A its Width.

6. A burner as in claim 4 wherein the longitudinally extending slots occupy between /3 and A the width of the burner strip.

7. A burner as in claim 4 wherein the burner strip has at least 3 parallel rows of longitudinally extending slots.

8. A gas burner comprising a mixing tube extending.

longitudinally, closed at one end and having an inlet opening at the other end for admitting gas and a longitudinal outlet opening extending lengthwise along the side of the tube, and a unitary burner strip across said outlet opening composed of sheet material .and having elongated parallel slots therein, said slots being no wider than the depth of the slots and being approximately ten percent narrower towards the ends of the burner strip and of such an order of magnitude as ordinarily to preclude flash back.

References Cited by the Examiner UNITED STATES PATENTS 702,873 6/1902 Holland 158-1 16 762,183 6/ 1904 Montgomerie et al. 1,568,771 1/1926 Roy 158116 2,044,528 6/1936 Guhl 15899 X 2,373,492 4/1945 Nelson et -al 158114 X 2,755,851 7/1956 Dow et al 158114 2,781,833 2/1957 Feyling 157117 X 2,828,532 4/1958 Taylor 158116 X 2,869,630 1/1959 Flynn 158105 3,053,316 9/1962 Flynn 158116 FOREIGN PATENTS 12,327 2/1903 Austria.

FREDERICK L. MATTESON, JR., Primary Examiner.

Claims

1. A GAS BURNER COMPRISING A MIXING TUBE HAVING A GAS INLET OPENING AND A LONGITUDINAL OUTLET OPENING, AND A BURNER STRIP ACROSS SAID OUTLET OPENINGS COMPOSED OF SHEET MATERIAL AND HAVING ELONGATED PARALLEL SLOTS THEREIN NO WIDER THAN THE DEPTH OF THE SLOTS, THE SLOTS BEING APPROXIMATELY TEN PERCENT NARROWER AT THE END NEAR THE GAS INLET OPENING AND OF SUCH AN ORDER OF MAGNITUDE AS ORDINARILY TO PRECLUDE FLASH BACK.