US2228296A - Gas burner - Google Patents

Description

atented Jan. 14, 1941 PATENT OFFICE GAS BURNER Sven W. E. Andersson, Evansville, Ind., assignor to Serve], Inc., New York, N. Y., a corporation of Delaware Application May 8, 1937, Serial No. 141,423

2 Claims. This invention relates to gas burners which provide a heating flame resulting from a mixture of air and a combustible gas, and more particularly to such a burner in which air is mixed with the combustible gas before it is discharged from the burner to produce and maintain the heating flame.

It is an object of the invention to provide an improved burner of this type which will require a minimum amount of attention, and which is of simplified construction and inexpensive to manufacture.

Another object of the invention is to provide such a burner having a safety cut-off mechanism 5 which can be easily manipulated when operation of the burner is instigated and which will eifectively shut off flow of gas to the burner when the burner flame is extinguished. The above and other objects and advantages of the invention will become apparent from the followlng description taken in conjunction with the accompanying drawing forming a part of this specification, and of which Fig. 1 is a vertical sectional view of a gas burner embodying the invention; Fig. 2 is a sectional view taken on line 2-2 of Fig. 1; and Fig. 3 is a vertical view of a burner, partly in section, illustrating a modification of the invention.

Referring .to Fig. 1, the improved burner embodying the invention includes a body member Ill having a threaded opening H which is adapted to be connected to a conduit of a gas supply line. The opening communicates with a chamber I2 which in turn communicates with a passage I4 through an orifice IS. The flow of gas through orifice I5 is controlled by a valve l6 which forms part of a safety cut-oil mechanism to be described hereinafter.

The passage I4 is in line with the opening II and the right hand end thereof is permanently sealed with a plug H. The opposite end of passage intersects a passage It which is threaded at its lower end to receive an adjustment screw IS. The passage I8 is sealed with a removable cap screw 20. By removing the cap screw 20 the adjustment screw It may be set to any desired position opposite the passage M to determine the maximum flow of gas to the burner and hence 5 the maximum size of the burner flame. v

The adjustment screw. is is recessed at both ends and provided with a small central opening 2| intermediate the recessed ends, so that the gas pressure in the upper part of passage l8 can 35 be measured at any time by removing cap screw 2|! and securing a manometer to the lower threaded end of passage I8. When the gas pressure is not at the desired value, the adjustment screw I9 may be moved to reduce or increase the flow of gas into the passage i8.

To the upper end of passage I8 is secured a member 22 having a passage 23 which converges and terminates in a discharge orifice 24. Within the passage 23 is provided a plug 25 having grooves 25'. The grooves 25' are at an angle with respect to the direction of gas flow whereby a whirling motion is imparted to gas flowing upward in passage 23. The gas discharged from orifice 24 passes into a mixing chamber 26 formed in the lower end of a burner tube 21 which is threadedly secured to the body member ID and concentric with respect to the passage I8 and orifice 24.

The lower end of burner tube 21 is provided with a plurality of ports or openings 28 to admit primary air into chamber 26. The primary air and gas, which is introduced into chamber 26 with a whirling motion, are thoroughly mixed in the chamber to provide a combustible gas mixture. Above the air inlet openings 28 the burner tube 21 slopes inward for a short distance, as indicated at 29, and then slopes outward gradually toward the upper end which is provided with a cap 30 having a plurality of openings 3|. The gas mixture formed in chamber 26 flows upward through the burner tube 21 and is discharged at the openings 3| at which region the burner flame is produced and maintained.

A tube 32 concentrically disposed about the burner tube 21 is secured by a cap screw 32' to the top of body member ID. The tube 32 provides an enclosed space about the burner tube 21 so that primary air introduced into chamber 26 through the openings 28 must be drawn downward from the upper open end of tube 32. By terminating the upper end of tube 32 closely adjacent to the openings 3| in cap 30, the direction of flow of air drawn downward in tube 32 is reversed considerably due to the fact that the flow of air is upward about the burner flame, as indicated by the arrows in Fig. 1. With this airrangement particles oi dust and lint in the air tend to move upward about the burner fiame and are separated from air which is drawn downward within tube 32. The tube 32, which may be referred to as a dust preventionv tube since itinsures delivery of clean primary air into themix ing chamber 26, is described more fully in Forberg Patent. No. 2,069,062.

Within'the tube 32 is arranged a sleeve 33 having an inward extending flange 34 at its .lower end. The sleeve 33 is vertically movable within tube 32 by a member 35 which is secured thereto and extends outward in a vertical slot or opening 36. A spring clip 31, which is secured to the sleeve 33 and frictionally engages the inside of tube 32, is provided to maintain the sleeve 33 in any desired vertical position. The sleeve 33 constitutes an air shutter for controlling the quantity of primary air admitted into the mixing chamber 26. When the sleeve is in the position shown in Fig. 1, the flange 34 is substantially valve IS in chamber l2.

tlon 29 of'the burner tube 21, so that the maximum amount of primary air is admitted past the burner tube 21 and flange 34 into the mixing chamber 26. As the sleeve 33 is moved downward the amount of primary air admitted into the mixing chamber 26 is reduced due to the narrowing of the opening between the flange 34 and sloping portion 29 of the burner tube 21.

- When the flange 34 is in the position indicated in dotted lines in Fig. 1, a minimum amount of primary air is admitted into chamber 26 through the openings 28.

If for any reason the burner flame is extinguished it is desirable to shut ofi the flow of gas to the burner. This is accomplished by providing a safety cut-off mechanism including the The valve I6 is of the ball type and is urged to its closed position by a coil spring 38 which is maintained in position within the recess of a cap screw 39. The lower enlarged head of a pin 40 bears against the valve l6 to move the latter to its open position against the action of coil spring 38. The pin 40 extends upward through an opening 4! in the body member l0 and the upper end thereof may be thread edly secured to a push button 42. The push button is movable in a hollow sleeve 43 which may be formed integrally with the body member l0. A suitable packing 44 is provided about the pin 4| at the lower end of sleeve 43 to prevent leak age of gas through the opening 4|. Between the push button 42 and packing 44 is arranged a coil spring 45 which tends to move the pin 40 upward and thereby permit valve l6 to move to its closed position. 7

To maintain valve H3 in its open position during operation of the burner, the push button 42 is provided with an annular groove 46 to receive an outward extending bent end of a-bimetallic strip 41. The lower bent end of the strip 41 extends through an opening 48 in the tube 32. strip 41 extends upward within the tube 32 and is secured intermediate its ends at 49 to the upper part of tube 32. A portion of the sleeve or air shutter 33 is cut away, as shown most clearly at 50 in Fig. 2 to permit free radial movement of the strip 41. extends upward into the vicinity of the burner flame. The upper end of strip 41, which serves as a heat conductor, may be plated with a suitable metal having a greater resistance to corrosion than the metals used in forming the bimetallic strip. Instead of plating the upper projecting end of strip 41, a suitable piece of metal 5| having a high resistance to corrosion may be secured thereto. To prevent flow of heat from the strip 41 to the tube 32 suitable insulating material 52 is provided at the region where the strip is secured to the tube 32.

' The operation of the burner and safety device just described is substantially as follows: To start.

From the tube 32 the strip 41 the burner the push button 42 is pressed downward to move valve 16 to its open position. This permits gas to flow from chamber I2 through ,orifice l5, passages l4, l8, and 23, and discharge orifice 24 into the mixing chamber 26. In chamber 26 the gas is mixed with primary air which is admitted through openings 28 and controlled by the sleeve or air shutter 33. The gas mixture flows upward through burner tube 21- and openings 3| at which region the gas mixture is ignited to provide the burner flame. The upper projecting end of strip 41 is heated by the burner flame, and, when the strip is sufficiently heated, the lower part thereof will be flexed outward and the bent lower end will extend into the grooved portion 46 of push button 42, as shown in Fig. 1. When this occurs the push button 42 may be released and valve I6 will remain in its open position.

If for any reason the burner flame is extinguished the bimetallic strip 41 will no longer be heated, whereby the lower part of the strip will be flexed inward and release the push button 42. With the extreme lower end of strip 41 no longer extending into the grooved portion 46 of push button 42, the coil spring 45 will be effective to move pin 40 upward and coil spring 38 will cause valve l6 to-move to its closed position and completely shut off the flow of gas to the bumer.

The construction of the burner and safety cutofl mechanism issuch that a simple and compact structure isl'provided which will occupy a minimum amount of space. In starting the burner it is only necessary to press the push button 42 and then ignite the gas mixture at the openings 3|. After a short interval of time the push button may be released when the strip 41 has deflected .outward into the grooved portion 46 of the button. Since the bimetallic strip 41 is located within the tube 32 it is well protected. Only a relatively few parts are required to provide the burner since the mixing chamber 26 forms part of the burner tube 21 and the latter is so shaped that the sloping wall portion 23 from only in the provision of a second safety valve which cooperates with the safety valve II to prevent leakage of gas from the body member it. In this modification a valve seat 53 is provided at the orifice 4! through which the lower reduced portion of pin 40' extends. The region of pin 40 where it becomes larger in diameter serves as a valve 54 which cooperates with the seat 53. The pin 40' is provided with a flange II at its upper end, and between this flange and packing 44' is arranged a coil spring 43'. The

embodiment illustrated in Figs. 1 and 2. When push button 42' is pressed downward to open valve l6 and instigate operation or the burner, the valve 54 is moved to its closed position on the seat 53. In addition to the packing 44', therefore, additional safety is provided by the closing of valve 54 so that no leakage oi. gas will occur' from the body member Ill through the orifice 4|. When valve I6 is moved to its open position the downward force exerted by coil spring 51 must overcome the upward force exerted by coil springs 45' and 38. By providing the push button 42' with the coil spring 51, the button may be pressed downward a little more than is actually necessary to open valve [6, whereby the lower bent end of bimetallic strip 41 will readily enter the space above the flange 56 and prevent upward movement of the push button when it is released.

Although particular embodiments of the invention have been shown and described, it will be apparent that-modifications and changes may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. In a gas burner comprising a valve housing having a burner tube extending from said housing and a dust prevention tube surrounding said burner tube and forming the inlet for primary air, a self-closing gas cutofl valve in said housing, a member manually operable from the exe terior of said casing for moving said valve to its open position, a thermostatic element comprising a bimetal strip secured at one end inside said dust tube adjacent the flame tip of said burner tube and extending substantially to the valve housing end of said tubes with its free end movable by temperature responsive flexure within the annular space between said tubes, a heat conductor connected to said thermostatic strip and arranged to be heated by the burner flame, and a detent operated by the movable end of said thermostatic strip to engage said manually operable member when the latter is in its valve opening position and the thermostatic strip is heated by the burner flame, and to release said member to permit said valve to close when the thermostatic strip QOOIS upon lack of burner flame.

2. Apparatus as set forth in claim 1 in which said manually operable member has a notch, and said detent is formed by a flange on the movable end of said thermostatic strip and adapted to engage in said notch when the strip is heated and the member is in its valve opening position.

SVEN W. E. ANDERSSON.

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