US3303869A - Radiant burner - Google Patents

Description

Feb. 14, 1967 Mo-roo HAYAMA 4 3,303,869

RADIANT BURNER Filed May 6, 1964 2 Sheets-Sheet 1 INVENTOR. MoToo HAYAMA ATTORNEY RADIANT BURNER 2 Sheets-Sheet 2 Filed May G, 1964 INVENTOR MOTOO H AYAMA 7/ ATTORNEY United States Patent 3,303,869 RADIANT BURNER Motoo Hayama, Tokyo, Japan, assignor to Caloric Corporation Filed May 6, 1964, Ser. No. 365,281 1 Claim. (Cl. 158-116) This invention relates to a burner of the type in which a gaseous fuel is burned on the surface of a screen in which the resulting incandescence generates infra-red and, possibly, other rays.

Burners of this type are presently known and, when use-d in the broiler or in the oven compartment of a cooking stove, or as space heaters in other fairly draft-free, enclosures, they operate satisfactorily. But, I have discovered that lthe presence of perceptible drafts, or wind pressure uctuations, interferes with the satisfactory operation of the burner and may partly, or wholly, invert, or partly, or wholly, extinguishing the ame.

It is therefore one object of this invention to produce a radiant burner of the type set forth, which will operate satisfactorily in the presence of drafts or wind pressure fluctuations of a caliber which would adversely affect the operation of burners of the type above referred to Which are not constructed according to this invention.

Another object is to accomplish the purpose set forth without materially increasing the cost, weight or size of the burner.

The full nature of the invention will be understood from the following specification and the accompanying drawings in which:

FIG. l is an exploded perspective View showing the parts of a burner embodying the invention and the order in which they are assembled.

FIG. 2 is a side elevational View of the assembled burner.

FIG. 3 is a longitudinal Sectional view taken through the median line of the burner.

FIG. 4 is a Sectional view looking in the direction of line 4 4 on FIG. 3.

As best shown in FIG. 1 a burner embodying this invention includes a hollow burner head of the desired size and shape, a venturi 12 which is connectable to a source of gaseous fuel, and a perforated bale 14 for effecting substantially uniform gaseous fuel pressure with-in the burner head. One side of the burner head is provided with an opening 16 which is defined by a rim 18.

The burner further includes an inner combustion sustaining screen assembly which preferably consists of two, or more, screens 20 and 22, when propane, or butane, or natural gas is used, and which consists of three or more such screens when manufactured gas is used. The screens can be of different mesh, but in practice, I found that 40 mesh screens operate satisfactorily. The central, or body portions of the screens which overlie opening 16 are transversely, or longitudinally, corrugated, or undulated, as at 24, and are surrounded by flat marginal portions 25 which abut the inner edge of rim 18 of the burner head. The purpose of the undulations is set forth in U.S. Patent No. 3,122,197, of February 25, 1964, and is, therefore, not repeated here.

Overlying screens 20 and 22 is a spacer 28, made of asbestos, or other heat resisting material, and overlying this spacer is an outer shield screen 30 which is preferably similar to screens 20 and 22. Overlying screen 30 is a clamping frame 32 the sides and ends of Which are provided with holes 34 which correspond to holes 36 in the sides and ends of spacer 28 and in the sides and ends of rim 18. The screens 30, 22 and 20 and spacer 28 are secured in position by screws 38 which pass through holes 34 and 36 and are engaged by nuts 40.

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To give the burner a finished appearance, I provide a cover 42 which conceals clamping plate 32 and the pendent anges 44 of which conceal the edges of the screen assembly.

Cover 42 is provided with openings 48 and is supported by ferrules 50 the hanger bolts 52 of which pass through openings 49 in clamping plate 32, in spacer 28 and in rim 18 and are engaged by nuts 54. The cover is detachably secured in position by screws 52' which engage threaded holes in ferrules 50. It will be noted that ferrules 50 raise the upper at surface of cover 42 to provide a solid shield which extends well above the surface of shield screen 30, better to protect against drafts.

In the burner described, combustion takes place on the surface of screen 22, or in the compartment formed between screens 22 and 30. By this arrangement, the ame is protected by shield screen 30 Which acts as a pressure reducer and ditfuses the drafts and blasts of air prevailing in the area in which the burner may be used and prevents inversion or extinguishment of the ame which would take place in the absence of outer screen 30.

In addition to the protection atforded by outer screen 30, the use of two, or more, screens,20 and 22 serves to increase the depth of the holes through which the gaseous fuel must pass before reaching the combustion compartment and thus further discourages inversion of the ame. Likewise, 'superimposition of two or more screens 20 and 22 produces a larger number of smaller holes and increases the velocity of the ow of gas from the burner head to the combustion surface and still further discourages inversion of the ame or back fire. The superimposition of screens 20 and 22 also breaks the gas into smaller Streams and makes for better mixture of the gas with the combustion air. Also, cover 42 being spaced from shield screen 30 also serves to deflect, or weaken, lateral drafts thus Preventing, or minimizing entra-inment of the combustion air in the vicinity of screen 30.

To ignite the burner, I provide outer screen 30 with one, or more, holes 56 through which the ame of a lighted match `rnay be introduced into the space between screens 22 and 30. Alternately, a hole, or notch, 58 can be provided in one of the peripheral anges of cover 42 to afford access to the space between screens 22 and 30.

As stated, the number, and the mesh, of the screens used can vary with the type of gas used and with the conditions under which the burner is to be used. The same is true of the thickness of spacer gasket 28. In practice, I find that 40 mesh screen, and a gasket from about 2?/16" to about 9/16 is satisfactory.

From the foregoing it can be seen that I have produced a radiant burner in which the combustion sustaining surface is amply protected so as to prevent inversion or extinguishment of the ame under conditions which the combustion surface is exposed.

What I claim is:

A gaseous fuel burner including:

a burner head adapted to receive a gaseous fuel mixture,

one side of said burner head having an opening therein,

a substantially flat rim surrounding said opening,

an inner screen Overlying said opening with a peripheral portion thereof resting on the rim of said opening,

a spacer resting on the periphery of said screen,

an outer screen Overlying said inner screen with a peripheral portion thereof .resting on said spacer,

said inner and onte-r screens defining a combustion compartment therebetween,

a clamping frame resting on the periphery of the outer screen and Overlying said spacer for clamping said screens and said spacer to said rim,

ferrules resting on said clamping frame,

a cover having a flat frame resting on said ferrules and 3,040,805 6/ 1962 Lambert.

-ipfilced frolm Sidputercreen, 1 d f 1 3,107,720 10/1963 Van swindefen. sa cover a so avng a ange enc osng sai erru es,

the edges of said clamping frame, the edges of said 3'122'197 2/1964 Salonara et al' spacer and the edges of said screens, 5 312041094 8/1965 Hmslngaand means for supplying a gaseous fluid mixture to 3204683 9/ 1965 Riffet al.

said burner head and through said inner screen to said compartment where said fuel mixture is com- FOREIGN PATENTS busted on the outer surface of said inner screen,

there being an ignition opening leading to said com- 1 494,087 10/1938 Great Britam' partment for the admission of means for igniting the 893554 4/1962 Great Britainfuel in said compartment. 371,237 9/ 1963 Switzerland.

References cited by the Examinef FREDERICK L. MATTESON, JR., Primary Exammgr.

UNITED STATES PATENTS 15 K 1 506,964 9/1924 Antrim 126 92 H. B. RAAEY, Assstant Examne.

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