US3526367A - Gas burner - Google Patents

Description

Sept. 970 J, M. TRn-n-:Yv I 3,526,367

GAS BURNER Filed May 9, 1968 ATToEWE VS United States Patent O 3,526,367 GAS BURNER John Massey Trihey, Burwood, Victoria, Australia, as-

siguor to Vulcan Australia Limited, Burwood, Victoria, Australia, a corporation of Australia Filed May 9, 1968, Ser. No. 727,883 Claims priority, application Australia, May 12, 1967, 21,656/ 67 Int. Cl. Bb 1/14 U.S. Cl. 239-556 6 Claims 'ABSTRACT OF THE DISCLOSURE A gas burner in which a combustible gas and air mixture issues from a chamber through openings in the chamber wall as a plurality of jets. The wall comprises inner and outer sheet members disposed face to face and the inner sheet member is perforated by a plurality of holes which communicate with said openings via passages defined between the sheet members whereby small jets are formed at the bases of the main jets.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to gas burners and more particularly to multi-jet gas burners.

lDescription of the prior art In multi-jet gas burners, which may be either for industrial or domestic heating applications, the burning jets are generally formed at a plurality of jet openings in a wall of a chamber which is supplied with a combustible gas and air mixture. The gas usually ows to the chamber via a Venturi nozzle having an air inlet opening whereby suction is generated within the nozzle to draw in air for mixing with the gas. The amount of air entrained 1s dependent on a mass flow of the gas through the nozzle and this is an important reason for the fact that there has hitherto been no mass-produced burner, particularly burners used under radiants, which can operate satisfactorily on a supply of either coal gas or natural gas. Natural gas has a much higher calorific value than the coal gas in reticulated town supplies and natural gas has a lower mass ow of gas than town gas for the same heat capacity. This lower mass flow in natural gas burners leads to air entrainment problems and it is usual to provide natural gas burners with a relatively large diameter Venturi nozzle and larger jet holes to reduce back-pressure for maximum air entrainment. This in turn leads to low gas velocities in the supply manifold and at the jets and if such a burner is supplied with coal gas the flame at the jets tends to burn-back into the manifold. On the other hand, if a town coal gas burner (which has a relatively small diameter Venturi, small jet holes and therefore relatively high gas velocities) is supplied with natural gas the flames tend to lift off the jets. Also the back-pressure makes air entrainment difiicult.

SUMMARY OF THE INVENTION The present invention provides a novel -gas burner construction which is particularly suitable for mass-production. The construction according to the invention also enables the mass-production of burners which will operate satisfactorily on coal gas or natural gas. According to the invention there is provided a gas burner comprising a chamber to receive a combustible gas and air mixture which chamber has a wall perforated by openings for the passage of said mixture from said chamber in a plurality of jets, wherein said wall comprises inner and 3,526,367 Patented Sept. 1, 1970 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of one form of burner constructed in accordance with the invention;

FIG. 2 is a cross-section on the line 2 2 in FIG. 1;

FIG. 3 is a View on the line 3 3 in FIG. 1 and is esentially a plan of part of a burner plate incorporated in the burner;

FIG. 4 is a cross-section on the line 4-4 in FIG. 3;

FIG. 5 is a broken and exploded perspective view of a modified burner plate;

FIG. 6 is a broken plan of the modified burner plate shown in FIG. 5;

FIG. 7 is a cross-section lon the line 7-7 in FIG. 6; and

FIG. 8 is a cross-section on the line 8-8 in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The burner illustrated in FIGS. 1 to 4 comprises a pair of body plates 5 which have a generally rectangular outline and have pressed portions `6. The plates are placed face to face so that their pressed portions register with one another to define a chamber 7 extending along the upper edge portions of the plates and a supply manifold -8 which communicates with chamber 7. The inlet end of supply manifold 8 is in the form of a convergent nozzle 9 and the supply manifold diverges outwardly in the direction away from this nozzle. In use of the burner, a gas supply pipe is inserted into nozzle 9 so that a space is left between the nozzle and the gas pipe. Gas flows from the pipe via the nozzle into manifold 8. The suction caused within the nozzle by the ow of gas draws in air through the clearance space and this air mixes with the gas in the manifold 8.

The top of chamber 7 is closed by an elongated burner plate denoted generally as 11 and formed as a composite body from three metal strips 12, 13A, 13B, which are spot welded together, the longitudinal edges of this plate 11 fitting into crimped upper margins 10 of plates 5. Strip 12 has two longitudinal rows of equispaced holes 16, 17 punched in it, the holes 16 of one row being staggered with respect to holes 17 of the other row. Strips 13A, 13B also have two longitudinal rows of holes 18, 19 punched through them so as to register with the holes 1'6, 17 in strip 12. Holes 18, 19 through strips 13A, 13B are of smaller diameter than the holes 16, 17 in strip 12.

Further holes 21 are punced through strips 13A, 13B so that each is located between a pair of holes 18 or 19. As shown in FIGS. 3 and 4 each hole 21 is adjacent three of holes 18, 19 disposed in a triangular array in strips 13A, 13B. Above each hole 21, plate 12 is pressed so as to form a three-legged recess or trough 22 in its under side. The legs of each recess 22 are in T-formation with the hole 21 communicating with it at the junction of the T. T'he ends of the legs of the recess communicate respectively with the three of holes 16, 17 in strip 12 which register with t-he triangular array of holes 18, 19 in strips 13A, 13B. There is one hole 21 for every three of holes 16, 17 and each hole 21 communicates with three 3 of the holes 16, 17 via a T-shaped passage defined by a recess 22.

In use of the burner, combustible gas and air mixture in chamber 7 issues through - holes 18, 19 and is lit at holes 16, 17 to form ames 423. Some gas and air mixture ows through holes 21 into the T-shaped passages defined by recesses 22 and issues from the three ends of each passage into holes 16, 17 to cause small retention flames 24. Flames 24 are fed with much less fuel than flames 23 since there is only one feed hole for every three flames 24 and the size of the feed passages thereto are relatively small. However, ames 24 are sufficient to ensure that the gas in ames 23 is ignited at the outlet of holes 18, 19 so that ames 23 cannot lift-off the burner.

FIGS. to 8 show a modified form of burner plate 111. This of similar construction to the previously described burner plate 11 and like parts and features have been denoted by like reference numerals with primes added. The two strips 13A, 13B of plate 11 have been replaced by a single strip 131 in plate 111 and, whereas recesses 22 of plate 11 were formed as T-shaped troughs in the upper strip, the recesses 221 of plate 111 are domeshaped, each being formed by pressing a dish upwardly into plate 121 so that it breaks into the appropriate three holes 161, 171. The function of recessess 221 is equivalent to that of recesses 22 in that they serve as passages for flow of gas and air mixture from holes 21 in strip 131 to the holes 161, 171 to cause small retention flames at the bases of the main jets issuing from the latter holes.

All of the above described burner components are particularly suitable for mass-production since they are comprised entirely of pressed sheet metal components which can be stamped and pressed as requi-red before being assembled and welded together. Moreover the particular construction of each form of burner plate not only causes the formation of retention flames which prevent the main flames from lifting oliC but it also provides relatively small obstruction to the gas flow so that the back pressure caused in chamber 7 is quite low. This in turn means that the Venturi nozzle 9 can have a relatively small cr-oss-section since sufficient air can be entrained for complete combustion with relatively low mass ow of gas. The Venturi nozzle can be such as to give high enough velocity of gas flow to avoid any tendency for burning back to occur if the burne-r is supplied with coal gas. Thus the burner can operate on either coal gas or natural gas and it has been found that it will provide sufiicient heat on either gas to heat radiant elements. It has also been found that the burner has an exceptionally good turn-down ratio of up to to 1.

It is to be understood that the illustrated constructional details are given only by way of example and may be varied considerably to suit different applications. For example, the invention may be applied to both the cooking range burners and the griller burners of domestic gas stoves. In the case of a cooking range burner, the chamber could be generally cylindrical and the composite perforated wall curved to constitute the peripheral wall of this chamber. Such variations may be made without departing from the spirit and scope of the present invention as defined by the appendent claims.

What it is desired to secure by Letters Patent is:

1. A gas burner comprising a structure defining a chamber to receive a combustible gas and air mixture, said structure comprising a plate-like wall of said chamber, said plate-like wall being perforated by openings for the flow of said mixture from said chamber in a plurality of main jets issuing transversely of the wall, said wall being of laminated construction comprising inner and outer sheet laminations disposed face-to-face, the inner lamination being perforated by holes which do not extend through the outer lamination, a plurality of passages extending along the interface between the laminations to provide communication between said holes and said openings to provide for auxiliary ows of said mixture through said openings and said passages such that said mixture will issue from said passages as auxiliary jets directed into the main jets at the roots of the main jets and transverse thereto, said openings being arranged in at least one pair of parallel rows, the openings of each row of said pair being equi-spaced with respect to each other and staggered with respect to the openings of the -other row of the pair such that the two rows form successive groups of three openings disposed in triangular array, each said group of openings including at least one of said holes which hole is disposed midway between the two openings of its respective group of openings which are in the same row and is connected with each of the openings of the group by one of said passages.

2. A gas burner as claimed in claim 1 wherein said passages are in the form of T-shaped troughs.

3. A gas burner as claimed in claim 1 wherein said passages are defined by generally dome-shaped recesses in one of the sheet laminations.

4. A gas burner comprising a structure defining a chamber to receive a combustible gas and air mixture, said structure including a plate-like wall of said chamber, said plate-like wall being perforated by openings for the flow of said mixture from said chamber in a plurality of main jets issuing transversely of the wall, said wall being of laminated construction comprising inner and outer sheet laminations perforated by holes which do not extend through the outer lamination, a plurality of passages extending along the interface between the laminations to provide communication between said holes and said openings to provide for auxiliary flows of said mixture through said openings and said passages such that said mixture will issue from said passages as aux iliary jets directed into the main jets at the roots of the main jets and transverse thereto.

5. A gas burner as claimed in claim 4 wherein said passages are defined by recesses pressed into one of the sheet laminations.

6. A gas burner as claimed in claim 5 wherein each passage connects one of said holes with a plurality of said openings.

References Cited UNITED STATES PATENTS 1,482,5.29 2/ 1924 Taylor 239-556 X 1,729,149 9/1929 Brown et al. 239--55-8 X 2,588,895 3/1952 Tavener 431-349 FOREIGN PATENTS 1,489,404 12/1967 France.

M. HENSON WOOD, JR., Primary Examiner J. I. LOVE, Assistant Examiner U.S. Cl. X.R. 239-548; 431-349

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