US2652108A - Gas fueled pilot burner having a bimetallic primary air valve - Google Patents

Description

P 1953 c; F JENKINS ,5

GAS FuELEb P'ILOT BURNER HAVING A BIMETALLIC PRIMARY AIR VALVE Filed Jan. 19, 1948 Snventor GEO/7615 E JEN/ 1M5 Patented Sept. 15, 1953 I GAS FUELED PILOT BURNER HAVING A BIMETALLIC PRIMARY AIR VALVE George F. Jenkins, Minneapolis, Minn, assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application January 19, 1948, Serial No. 3,029

4 Claims. (01. 158-118) This invention relates to gas burners and, more particularly, to gas burners of the type used to serve as a pilot light for a larger gas burner and to heat a thermoelectric generator in an arrangement similar to that shown in Ray Patent Number 2,297,718.

Burners of this type usually provide spaced fuel mixture is made too rich, a thermocouple element becomes covered with soot, which drastically cuts down on the output of the thermocouple. While the manual adjusting means usually provided on burners of this type, for regulating the primary air entering the burner, are generally satisfactory for giving the proper mixture at any particular ambient air temperature, the adjustments do not provide for variation in the mass of air entering the burner due to changes in the density of the air, resulting from changes in the air temperature. Due to the fact that the ambient air temperature adjacent a furnace varies over a wide range, it has been the practice in burner installations of this type, to adjust the air inlet to the burner to provide a much richer fuel mixture than is desirable for heating the thermopile, so as to prevent the burner from going out. This has caused rapid deterioration of the thermocouple elements with consequent improper operation of controls energized thereby.

It is the general object of this invention to provide a burner which overcomes the above mentioned difficulties.

A more specific object of the invention is to provide a burner having means thereon to regulate the flow of primary air into the burner in response to changes in ambient air temperature.

Another object of the invention is to provide a fuel burner having a manually adjustable main air opening and an automatically adjustable auxiliary air opening therein for varying the flow of primary air into the burner.

A further object of the invention is to provide an inexpensive burner that maintains a uniform fuel-air ratio in an atmosphere having varying air temperature.

Other objects of the invention will become apparent upon reading the following detailed description of the invention in conjunction with the accompanying drawing wherein:

Figure 1 is an elevational view of the burner of this invention showing parts thereof broken away; and

Figure 2 is a cross sectional view of the burner taken on line 22 of Figure 1.

The burner comprises a main body portion generally designated by the numeral it. This body portion consists of a hexagonal portion M, an annular extension [2 at the lower or inner end thereof, a reduced annular portion 13 adjacent the upper or outer end of the hexagonal portion, and a longer and still further reduced annular portion I 4 beyond the annular portion 13. This particular body construction enables the burner to be mounted in an adjustable bracket for supporting the burner in proper relationship with a thermoelectric generator (thermopile), not shown herein but illustrated in a copending application of Charles E. Bodey, Serial Number 787,665, filed November 24, 1947, and now matured into Patent No. 2,605,296. Suitably mounted. on'the upper or outer end of the portion It is a burner head l5, the details of which form no part of this invention.

A threaded axial bore [6 extends inwardly from the inner or lower end of the burner body. This bore tapers down at I! to the lower end of passage IB which extends from said bore to the upper or outer end of the burner body. The adjacent portions of said bores l6 and I3 serve as a mixing chamber for gas and air.

A main primary air opening [9 is formed in one of the side walls of the portion H of the burner body. Cooperating with this hole It, to regulate the rate of air flow therethrough, is a burner nozzle 20.

The burner nozzle has a jet portion 2! of smaller diameter than the bore l6, and a large and threaded portion 22 of the same diameter as bore It, a nut-like enlargement 23 extending below the portion 22, and a reduced and exterlorly threaded portion 24 extending below the portion 23. The nozzle portion 22 is so related to the opening i9 that inward andoutward adjustment thereof varies the effective size of the opening ill to regulate the quantity of air that will flow .therethrough due to the aspirating effect of the nozzle. The threaded portion 24 is adapted to be connected to a gas supply conduit, not shown.

A second or auxiliary air opening 25 is provided in another wall of the hexagonal portion II to provide additional air flow to the burner under certain conditions to be described hereinafter.

Cooperating with this air opening 25, is a bimetallic valve member 26 having a flat portion 27 adapted to fit against the side of the portion I I of the body to cover the opening 25, an arcuateportion 28, an enlarged and centrally apertured portion 29 (Figure 2), and a portion 30 bent at right angles to the portion 29 so as to lie against a hexagonal surface diametrically opposite the: bimetallic portion 21. The portion 29 of the bimetallic member fits around the extension [2 of the burner body and is held thereon by means of a bead |2a formed by swaging the lower end of the portion i2. The bimetal valve 26 is adjusted so as to be flat against the mouth of opening 25 at the coldest operating air temperature of the furnace.

Operation The burner, when mounted in its proper relationship with a main burner and thermopile, is placed into operation by connecting the portion 24 to a suitable source of fuel and igniting the fuel and air mixture passing through the burner tip [5. The elements of the burner will have the positions shown in Figure 1 of the drawing when the ambient air temperature in the furnace is at its coldest operating condition. As the temperature of the air surrounding the burner increases, due either to external causes or to the heat generated by the furnace, the bimetallic valve member 26 will move portion 21 thereof away from opening 25 to permit more and more of the less dense air to enter the burner to maintain the mass ratio of air to fuel substantially constant. As indicated above, the initial fuel air ratio is determined by the relative position of the nozzle 20 with respect to the burner body I or, more exactly, the relative position of the upper end of the threaded portion 22 of the nozzle with respect to the opening IS in the body of the burner.

As various modifications of the burner of this invention will become obvious to those skilled in the art without departing from the spirit of the invention, such as one having an entirely fiat bimetallic valve member screwed to a burner body, it is to be expressly understood that the scope of the invention is to be determined solely by the appended claims.

I claim as my invention:

1. A burner comprising a hollow body, an orifice member within said body, a first air opening in a wall of said body, said orifice member having an enlarged diameter portion adjustable with respect to said opening to determine the flow of air therethrough, a second air opening in said wall of said body and spaced from said enlarged diameter portion, and a temperature responsive member having a portion for covering said second air opening and a portion engaging said body for retaining it on said body, said temperature responsive means being responsive to the temperature of the air flowing over it and adjusted to close only said second air opening at a predetermined low ambient operating air temperature.

2. A burner comprising a hollow body, a jet member within said body and having a threaded enlarged diameter portion; a first air opening in a wall of said body arranged to cooperate with said portion of said jet member to adjust the flow of air therethrough; a second air opening formed in said wall adjacent the upper end of said jet member; and a bimetallic member having a fiat portion for covering said second air opening and a washer-shaped portion surrounding said body and an intermediate arched portion, means on said body engaging said washershaped portion for retaining said bimetallic member on said body, said bimetallic member being so constructed and adjusted that the fiat portion bears against the body to seal the second opening at the lowest air temperature adjacent the burner air inlet and withdraws from the air opening at higher temperatures.

3. A burner comprising a hollow body, a jet member within said body, said member having a relatively large threaded portion adjacent an end jet portion, a first air opening in a wall of said body and arranged to cooperate with said threaded portion so that the end of said threaded portion adjacent said jet portion adjusts the flow of air therethrough, a second smaller air opening formed in said wall adjacent said jet member and spaced from said threaded portion, and a bimetallic member having a flat portion for covering said second air opening at the lowest air temperature adjacent the burner air inlet and for withdrawing from the air opening at higher temperatures and a washer-shaped portion surrounding said body and arranged to cooperate with said body to hold said member on said body.

4. A burner comprising a hollow body, a jet member within said body having an enlarged portion adjacent a jet portion, a first air opening in a wall of said body arranged to cooperate with said enlarged portion so that said enlarged portion may be adjusted to control the flow of air therethrough, a second air opening formed in said wall adjacent the upper end of said jet member, said body having a fiat surface around the outer end of said second air opening, and a bimetallic member having a fiat portion for engaging said flat surfaces and covering said second air opening and a washer-shaped portion surrounding said body, said washer-shaped portion having an extension shaped to bear against said flat surface of said body to prevent rotation of said member about said body and arranged to cooperate with said body to hold said member on said body.

GEORGE F. JENKINS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 703,625 Treen July 1, 1902 1,313,694 Hunter Aug. 19, 1919 1,472,554 Cox Oct. 30, 1923 1,870,253 Johnson Aug. 9, 1932 2,191,178 McCollum Feb. 20, 1940 2,263,999 McCollum Nov. 25, 1941 2,296,792 Kester Sept. 22, 1942 2,364,299 Kester Dec. 5, 1944 2,379,854 Harper July 10, 1945 2,450,790 Greaves Oct. 5, 1948 FOREIGN PATENTS Number Country Date 661,612 France Mar. 11, 1929 815,408 France Apr. 12, 1937

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