US2896703A - Gas pilot burner - Google Patents

Description

July 28, 1959 E. J. WEBER GAS PILOT; BURNER Filed Aug. 4, 1954 2,896,703 GAS PILOT BURNER Earl LWeber, Bay .Village, Ohio, assignor to American Gas Association, Incorporated, New York, N.Y., a corporation of New York Application August 4, 1954, Serial No. 447 ,704

2 Claims. (Cl. 158-115) This invention relates to gas pilot burners and more particularly to pilot burners for use in conjunction with the top burners of a domestic gas range.

The usual ignition system, providing automatic ignition of gas range top burners, employs a standing gas pilot humor in conjunction with flash tubes. Thesestanding pilot burners are continuously in operation and each releases heat at a rate of at least 200 B.t.u. per hour (usually more). If the range top section is divided (with two burners on each side) two such pilot burners are required. Consequently, there is an appreciable amount ofheat release to the kitchen as the result of pilot burner operation.

One object of the present invention is to provide a gas pilot burner which operates at a low input rate and gives off less heat than pilot burners heretofore used.

Another object of the invention is to provide a gas pilot burner which operates at such a low input rate and gives off such a small amount of heat that it makes possible the use of an individual pilot burner for each of the top burners of a gas range, eliminating the need for flash tubes.

A further object of the invention is to provide a low input pilot burner having inherent flame stability.

In accordance with this invention, there is provided a gas pilot burner comprising a thin needle element having an axial bore therethrough and preferably having a pointed tip, means to support said element in a generally vertical position, means to supply fuel gas to said element, whereby in operation the fuel gas burns at the tip of said element, and means to shield said element from surrounding air drafts.

The invention may be fully understood from the following description with reference to the accompanying drawing illustrating a preferred embodiment.

In the drawing:

Fig. 1 is a side elevational view, on approximately full scale, showing the gas pilot burner in. association with a main burner;

Fig. 2 is an elevational view of the pilot burner, on a relatively large scale, taken from the front of the burner;

Fig. 3 is a sectional view taken on line 33 of Fig. 2;

Fig. 4 is an elevational view taken from the rear of the pilot burner;

Fig. 5 is a plan or top view of the pilot burner; and

Fig. 6 is a cross-sectional view taken on line 6-6 of Fig. 3.

In Fig. l, the gas pilot burner, designated generally by reference numeral 10, is shown in association with a main burner 11, the pilot burner serving to effect automatic ignition of fuel gas-air mixture issuing from the main burner whenever it is turned on. The present invention is not concerned with the character of the main burner which may be of any suitable type or form. For example, the main burner, as shown in Fig. 1, may be of the type disclosed and claimed in my copending application Serial No. 447,705, filed August 4, 1954, now abandoned. Whenever the main burner is turned on, the gas- Patent Patented July 28, 1959 air mixture from its ignition port 11a is ignited byth pilot burner, and the flame at the ignition port ignites the gas-air mixture fromthe main ports 11b.

v Referring particularly to Figs. 2 to 4, the gas pilot burner provided by the present invention comprises a thin needle element 12 which is of tubular form and preferably has an oblique end 13 providing a pointed tip. Preferably, the element 12 is formed of thin stainless steel tubing similar to that of a 23-gauge hypodermic.

with and extends from alarger-diameter tubular section 14 through which fuel gas is supplied to the lower end of element 12.

Associated with the element 12 is a shielding enclosure which serves to protect the pilot burner from surrounding air drafts. In the illustrated embodiment, a supporting-fitting 15 surrounds and engages the tubular section 14 and threadedly receives a plate 16 which constitutes the bottom or base of the shielding enclosure. The plate.

16 is shown locked in position by nut 16a. Mounted on the plate 16 is a walled structure 17 on which there is provided a top 18. The structure 17 is preferably of the form illustrated and it has an opening 19 adjacent to the burner outlet port. The structure 17 also has an air ingress opening 20 at the lower front thereof and a line opening 21 at the upper rear thereof. Air enters the opening 20 and helps to support combustion of the fuel gas at the outlet port of element 12, while flue gases are permitted to leave through opening 21. The top 18 is preferably shaped as illustrated to provide front and rear hood portions 22 and 23.

In operation of the pilot burner, the burning fuel gas provides a pilot flame at the outlet port, and whenever the associated main burner is turned on, the air-gas mixture from the ignition port contacts the pilot flame through the front opening 19 of the shielding structure 17. The

pilot burner assembly may be mounted as shown in close proximity to the main burner so as to provide direct ignition without the aid of a flash tube.

A gas pilot burner of the character provided by this invention has a low input rate and at the same time has inherent flame stability. The input rate of such a burner is approximately 50 B.t.u. per hour, which is about onefourth of the input rate of gas pilot burners heretofore used. Thus, with individual pilot burners for each of the four top burners of a gas range, the total input rate is only 200 B.t.u. per hour which is one-half the total input rate of two ordinary gas pilot burners commonly employed together with flash tubes in association wit the four top burners of a gas range.

Prior to the present invention, the provision of a gas pilot burner with a low input rate presented a problem with respect to flame stability. The present invention overcomes that problem. The use of very thin tubing for the pilot tube and pilot port provides flame stability because the thin tubing minimizes heat conduction from the flame, and the very small port diameter slows the flow sufficiently that it results in diffusion of gas below the port. The flame from this diffused gas provides a selfpiloting action for the main flame and thus adds to the stability. Furthermore the preferred oblique and pointed form of the needle element 12 enhances the flame stability.

While this pointed tip feature is not essential, it is a preferred refinement.

In operation, the flow of gas through the tube to the burner tip at its open end is slowed, by the small diameter of the tubing and/or a flow control valve. As a consequence the gases, rather than flowing out in a jet, overflow the edge of the opening and back around the tip of the tube in a small bead. Thus, the tip of the needle is enveloped in the small flamewhen this bead is burning. The bead is only approximately inch in dimeter and immersion 'of its tip in the flame heats' it'to redness in the region of the flame because of the iie'edles thin gauge. The heat of the tip adds to the fiames sta bilit'y preventing extinguishment in circumstance when another pilots flame would be quenched.-

In addition to the advantages above set forth, it hasbeen found that the pilot burner provided by this invn-" tion is insensitive to gas pressure changes. Moreover,- the shielding' structure not only protects the burner elenient against air drafts but also protects it from spillage.

-While a preferred embodiment of the invention has been illustrated,- the invention is notlimited thereto biit contemplates such modifications and further embodk merits as may occur to those skilled in the art.

I claim:

1. A gas pilot burner adapted to produce a stabilized p'ilot flame at very low B.t.u'. input levels of the order of 50 Btu. per hour, comprising a gas supply line, 'a thin walled tubular burner tip capable of being heated at its p'ort end to a temperature which will support cotnbustiori at said slow rate of gas flow, said burner tip having an outside diameter of the order of .025 inch coupling means associated with said tip and connecting said tip to said gas supply line, means for maintaining the gas flow to 2, The gas pilot burner of claim 1 in which a shielding enclosure is provided about the tubular burner having a gas ignition opening, for location adjacent to the main burner to be ignited, air ingress and flue openings supplying air to and removing flue gases from said tubular pilot burner, the air ingress opening being located remote from the burner tip.

References Cited in the file of this patent UNITED STATES PATENTS 1,403,020 Everett Ian. 10, 1922 1,884,083 Miller Oct. 25, 1932 2,008,042 Sackett July 16, 1935 2,110,217 Gardner eta1. Mar. 8, 1938 2,285,704 Frank June 9, 1942 FOREIGN PATENTS 973,643

France Sept. 20, 1950

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