US1962200A - Burner and safety control therefor - Google Patents

Description

June 12, 1934. 5 LONERGAQ 1,962,200

BURNER AND SAFETY- CONT ROI; THEREFOR Filed Jan. 8, 1931 3 Sheets-Sheet 1 I 3 Sheets-Sheet 2 S. J. LQNERGAN BURNER AND SAFETY CONTROL THEREFOR Filed Jan. 8. 1951 June 12, '1 934.

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June 12, 1934. s 1 LONERGAN 1,962,200

BURNER AND SAFETY CONTROL THEREFOR Filed Jan. 8, 193 s She-ts-Sheet 3 Patented June 12, 1934 I 1,962,200 BURNER AND SAFETY oon'mon'rnnanron Simon J. Lonergan La Porte, Ind.,

Company, La Porte, Ind, a

Bastian-Morley assignor to corporation of Indiana Application January 8,

1931, Serial No.': 507,447

4 Claims. (01. 15 8117.1) I

My invention relates to gas burners and has to do particularly with a safety pilot control therefor. r

My invention has utility in numerous instances where the use of gas burners is required-for example, in connection with various water heater installations-and, to facilitate explanation of' my invention, ,1 will refer to the same in its application to one form of water heating apparatus. In certain forms of water heating apparatus,'it is customary to control the flowof gas to the burner automatically (thermostatically, or

otherwise) under the influence of the water in the storage tank to maintain the water in such storage tank at a certain desired temperature; and it is also customary to employ in connection therewith a pilot bumer to ignite the main burner when it is cut in from time to time by the automatic control means.

' For highest efliciency and greatest safety, it is desirable that the pilot flame be of a character that, if for any reason the'pilot light or flame should cease to burn, the flow of gas from the source to the burner (independently of the to going automatic main-flow control) will be cut off thereby preventing waste and well-known flame becomes extinguished. Another object of my invention is to overcome the foregoing objectionable conditions by providing a pilot structure including a stem-supported valve which is actuated by a thermal element, the valve stem being so controlled that it is positively free from any tendency to stick in either its open or closed, position. More particularly, my invention contemplates the use of a thermal element adapted to be subjected not only to the normal-heating 6?- action of the pilot flame but also to an additional heating effect by radiant heat'in the combustion chamber. This radiant heat, naturally, is of avarying nature and the thermal element is of such construction that this varying radiant heating effect produces a so-called breathing action of the same and the valve stem in the open position of the valve, whereby the valve stem pulsatesQ-so-to-speak, avoiding the possibility of sticking. I i

A further object of my invention is to provide a pilot flame structure adapted to consume only a amount of fuel. More specifically, my invention contemplates playing the pilot flame directly on a strip of thermostatic metal so so arranged that only, a small amount of heat dangerous and objectional conditions which may is required to produce the desired deflection of be caused'by escaping, non-burning gases; and it is moot the objects of my invention to provide a burner'struc'ture having, as a self-contained part thereof, means which serves not only as a pilot but which also serves to automatically control the flow of fuel to the burner discharge orifices in such a waythat the. gas supply (independently of any otherflow-control means), is cut into the only at times when the pilot flame is burn g.

. Pilot controlled devices have been employed I heretofore which embody stem-supported valve devices controlled in such away as to cut in or cut out the flow of gas to the main burner. In such structures, when thepilot flame is lighted,

the valve stem and valve are moved to-an open remain stationary forthe position where they entire period during which the pilot flame is buming. In some instances, this period may last for months, duringjwhichtime'fthe valve stem may tend to become corroded to such an extent that,

should the pilot flame become extinguished, the

valve stem'may stick so that the valve will not close. Also, dirt and foreign objects may tend to'co'llect uponthe'se valve stems of these prior structures during their stationary period with the result that they, may stick or-may not move properly or quickly in the event that the pilot the same.

An additional object of my invention is to providea pilot structure including a thermal element formed of a flat strip of thermostatic metal so positioned that thepilot flame is directed horizontally above the same within the combustion chamber so that incoming up-drafts of airare deflected from such flame.

Another object of my invention is to provide a pilot means which insures a slow cut-in of the fuel to the burner and a quick cut-out of the same. This end of the thermal element may I be so arranged that, when heated, its pick-up of the' fluel control valve to open the same is delayed but, upon cooling, its pick-up of' the valve is, instantaneous.

A-further object is. to provide a.- pilot unit which may be readily and quickly adjusted -to vary the' time and extent of opening of the fuel control valve, the parts of which unit are so conv structed that they move freely without binding a and with a minimum of wear.

Additional objects are tofprovide means of the foregoing dharacter which is thermostatically controlled and which is located near the burners -fiame elements whereby the pilot control I may function more positively in accord with the actual fuel conditions existent in the burner structure quired for combustion needs therein.

per se; to provide the pilot means as an integral part of the burner head or manifold, the same being well adapted to burners of the character disclosed in Letters Patent No. 1,753,962, granted April 8, 1930, for Gas burner; to simplify and reduce the number of parts in connection with burner equipment; and to reduce the cost of production and maintenance.

Other objects and advantages wil become apparent as this description progresses and by reference to the drawings wherein,

Figure 1 is ahorizontal section through the lower part of one form of structure embodying my invention;

Fig. 2 is an enlarged top plan view partly in section of the burner structure per se;

, Fig. 3 is an enlarged vertical section taken substantially on line 3-3 of Fig. 1;

Fig. 4 is a section taken substantially on line 44 of Fig. 3;

Fig. 5 is a. top plan view of another form of burner embodying my invention; and

Fig. 6 is a sectional view of a portion of a structure including the burner of Fig. 5, the section of which burner-is taken substantially on line 6-6 of Fig. 5.

It will be understood that while I have shown and will describe my invention as applied to a particular kind of burner for a particular form of water heater, yet I do not wish to be limited to such use because it is obvious that my invention has utility inother environments where similar conditions are to be met and similar results are sought. Referring particularly to the structure shown in Figs. 1 to 4, inclusive, the water heater embodies an outer, insulating shell 10 surrounding the wall of the. storage tank 11 providing an insulating space 12 adapted to be fllled with a suitable insulating material. The

walls 10 and 11 are extended downwardly beneath the tank bottom 13 providing a combustion chamber 14, the bottom of which is covered by a so-called drip pan 15 having a central opening 16 surrounded by an upstanding flange 16. -A somewhat larger and inverted pan 17 adapted to be supported by the burner (to be'described) is supported above the flange 16 with the depending flange 17 of the former telescoping in spaced relation the flange 16 The pans 15 and l7-provide in the bottom of the combustion chamber, and exteriorly thereof, a space 18 adapted to receive the body or manifold 19 of the burner structure embodying'my invention. Also, the telescopic relationship between these pans provides a secondary air trap which serves, to limit the amount of secondary air (passing through the space between the pans) admitted to the combustion chamber to substantially that re- The pan 1': is provided in its bottom with a plurality of openings 20 adapted to receive the tips or flame elements 21 of the burner, which tips may be, if desired, of a construction such as that disclosed in the aforementioned Letters Patent 1,753,962. Washers or disks 20 are passed over and rest upon the beveled surfaces 21'- of the tips 21 and the pan 17 seats upon these washers which trol.,oi, the temperature of the water in the tank through the medium of a thermostat device 22 which may take any desired form. 'I'he'particu lar thermostat which I have shown is of the quick-action type, and it is connected to the gas supply (not shown) and to the burner structure by means of pipes 23, 24 and gas cook 25. This thermostat operates to cut off the gas supply from the burner when the water in the tank reaches the desired temperature, and to cut in the gas supply when the temperature of the water is lowered below that point. The burner, therefore, includes a pilot device 26 (which will be described in detail hereinafter) for lighting the burner at proper intervals, which device is connected directly to the gas source through the thermostat 22 .(or otherwise) by means of a radial, open-bottomed passageway 28 for receivingthe'pipes 24 and 27 within the limits of the heater and to permit the burner to be sufficiently inserted up into the space 18 as to lie substantiallywithin the vertical limits of the heater and its combustion chamber for protection of these parts during handling of the heater and to permit ready detachment of such parts. Thisvarra-ngement also provides a mounting in which the main part of the burner is located outside thecombustion chamber in a cool zone so that it will at all times function to discharge its rated amount of fuel accordingto the existent fuel requirements.

The particular burner body illustrated takes a general U-shape and is formed to provide what I may term a main chamber 19* and an inlet chamber 19. The burner tips 21 are mounted on the body with their mixture bores in-communication with the main chamber 19 as best illustrated in Fig. 2. The mixture discharged from the tips 21 is adapted to be ignited by the pilot flame F when the thermostat 22 cuts in upon a drop in the temperature of the water in the tank. The pilot control must, for safety purposes, as will be well appreciated, be of such a character that if its flame be extinguished, at any time, the supply of gas will not be cut in to the burner even though the thermostat 22 does function to cut in the gas to the pipes 23, 24. I provide for this as follows: I

The inlet and main burner chambers 19 19 communicate with each other at one side of the burner body under the control of a valve. This valve, in turn, is under the thermal control of the pilot flame F. More particularly, the burner such casing to the burner body. This casing pro- 7 vides a pilot chamber 30 to which the pilot fuel pipe 27 and a pilot burner tip 30 are connected. This pilot tip is of the same general type as the tips 21 and is provided with a plurality of discharge slits 31 adaptedto discharge a like number of blue flame sheets downwardly and laterally toward the thermal member 47 and the'tips 21, respectively.

The burner body forwardly of the pilot casing 30 is slightly enlarged to provide a valve chamber 32 adapted to screw-threadedly receive a valve cage 33 supporting a valve 34. This valve cagev is provided at its inner end with a recess supporting a gasket 35 which seats against the cylindrical shoulder 36 (Fig. 3) when the valve cage is screwed into place to prevent the escape of gas past the valve cage into chamber 19 except when the valve 34 is open. The hollow or chambered part 37 of the valve cage, inwardly of the valve 34, communicates directly with the main manifold chamber 19 through a plurality of openings 38 in the cage wall (Figs. 2 and 3). The valve 34 is supported by a stem 39 which is slidably mounted in a centrally-disposed bore 40 in the valve cage and is long enough to extend through and beyond the valve cage. The midpart of the valve stem is provided with a plurality of grooves 41 which are adapted to receive any suitable kind of heat-resisting lubricant to reduce the friction between the valve stem and its bearing thereby aiding in the free and instantly-responsive movement of the valve stem,as

well as aiding insealing the stem against leakage. For positive safety assurance in the operation of the valve, it is desirable that means be provided which tends at all times to move the valve 34 toward its closed position.- To that end, in part, this valve is of such relative size and is so positioned with respect to the main gas flow, that gas flowing through the pipes 23,24 into the manifold chamber 19? tends to move the valve 34 into a closed position and to hold the same there. The pilot safety-control structure which my invention contemplates is adapted to oppose, under normal conditions, the closing tendency of the valve 34, and is adapted to hold such valve open to insure flow of gas to the burner so long as the pilot flame F is burning.

Specifically, I employ a flat strip of thermostatic metal 47 bent to a U-shape with one Uvleg, preferably, slightly longer than the other. This thermostatic strip is so constructed that it has on its inner side a metal section having a low expansion co-efficient while its outer side is formed of metal having a higherexp'ansion 00- efficient; whereby, as heat is applied to the thermostatic strip, the resulting motion of the metal (due to the Ushape and the metal arrangement) will be in a direction moving the U-arms of such strip toward each other, consequently moving the valve stem 39 inwardly to open the valve '34. and vice versa when such strip is cooled.

The shorter U-leg of member 47 is secured as by screw 48 to the burner body above the valve chamber so that the other and longer U-leg projects downwardly toward the projecting threaded end of the valve stem 39. The end of' this longer leg isbifurcate and loosely straddles a spool-like member 39 adjustably engaging the threaded end of the valve stem 39. Upon the spool 39 and outwardly of the thermal member 4'7 I mount a washer 39 and a spring 39. The

spool is so positioned that the engaged end of the thermal member 47, when cooled, is spaced from the inward end of the spool so that the former in its valve-opening movement (caused by heating) travels a predetermined distance before picking up the spool to open the valve 34. The spring 39 is normally so compressed that it expands and follows the end of the member' 4'7 in the foregoing movement ready for immediate pickup of the valve stem when the member is cooled. It will be noted that the pilot tip 30 is located in such a position with respect to the thermostatic strip 4'7 that the flame burning from its underside port 31 is directed vertically downward and strikes the periphery of the U-bend portion of such strip, thereby insuring movement of the thermostatic strip and valve so long as the pilot flame is burning. The strip 4'7 is .of such character that it is quickly responsive to heat conditions and will, consequently, open the valve 34 very quickly after the-lighting of the pilot flame, (dependent upon the position of spool 39*). Conversely, in the event that the pilot flame is extinguished, the thermostatic strip tends to cool quickly causing a rapid movement or deflection of the strip in an outward or spreading direction to close the valve '34 and cut off the gas from the main burner. The spool is obviously adjustable along the valve stem to vary the time of beginning of the opening movement of stem 39, and it may be adjusted so that a very small pilot flame (with minimum pilot gas consumption) may be employed to effectively open (and hold open) the valve. However, the closing action (due to spring 39 and the tension of strip 47) is always simultaneous with cooling and resulting movement of strip 47. This arrangement due to the delayed pickup action of the thermal strip and the quick closing action (due to the action of spring 39 and the tension of the strip '47) provides a thermal pilot control which I may term slow opening and quick closing.' The connection between the spool 39* and the bifurcate end of strip 47 affords a universal-like action between these parts compensating for the'obvious arcuate movement of the bifurcate end of strip 47 in its movements under heat and cooling conditions and insures a non-binding movement between these parts at all times.

The thermostatic strip is of suflicient length and it is so mounted that its U-bend portion projects upwardly a slight distance into the combustion chamber 14 through an opening 51 in the pan 17. This U-bend portion of the thermostatic strip 4'7 is, therefore, in addition to the action of the pilot flame F, subjected to radiant heat variations in the combustion chamber 14. More particularly, when the main burner is lighted, with the pilot flame also lighted, the thermal strip 4'7 is moved to open the valve 34 to a slightly greater extent than when the pilot flame only is effective upon the. ther- 'mostatic strip. When the main burner is shut off, or turned down, so-to-speak, there is a correspondingly slight movement of the thermal strip in theopposite direction (due to a slight radiant heating effect). This condition or action of the thermal strip may be continuously taking place to different extents due to varia tion in radiant heat with the result that the longer leg of the strip is caused to .pulsate or breathe with a resultant pulsating, breathing, or the like, motion of the stem 39 in its bearing so long as the valve 34 is open and the pilot flame is on. This action positiveiy prevents sticking of the valve stem and insures at all times the body or manifold 63 of the burner. The tips 64 of the burner project upwardly into the combustion chamber through suitable openings 65 of the pan 61. The openings 65 are, preferably, only slightly larger than the burner tips 64 whereby the amount of secondary air admitted to the combustion chamber 60 through such openings is limited and is dependent, mainly, upon the self-induction action set up by the flames discharged from the burner tips.

The inlet end of the manifold casing has an upwardly-projecting extension 66 with a gasreceiving chamber 6'7 in communication with the passage 68 of the pilot tip 69 which is screw threadedly mounted in vertical position in the upper portion of such casing extension. This pilot tip is provided with a laterally-extending discharge port '70 adapted to discharge the fuel in horizontal direction where it burns in a' comparatively narrow horizontally-directed flame, the end of which tends to lick upwardly toward the outer ends of the adjacent burner tips 64.

The inner U-bend portion of the burner body (at the juncture of the chambers '71 and '72) is provided with a threaded opening adapted to screw threadedly receive a valve cage '73 supporting a valve '74. The hollow or chambered part '75 of the valve cage, inwardly of the valve '74, communicates directly with the main manifold chamber '71 through a plurality of openings '78 in the cage wall (Fig. 5). The valve stem 79 is slidably mounted in the valve cage similarly to the previously-described form.

If it is found desirable to further insure against leakage of gas past the valve stem '79 when its valve '74 is open, I may provide-the valve stem near its inward end with a valve 80 which, as the stem is moved to the right (looking at Fig. 6) to open the valve '74, is moved into seated engagement with the valve seat 81 formed in the valve cage '73.

To aid in movement of the valve '74 toward and into its closed position, I mount a spring 82 on the projecting end of the stem "79 and confine the same under compression between the adjacent end surface of the valve cage '73 and a suitable washer 84 held in position upon the valve stem by a pin 85 passing therethrough. In this form aso, this closing tendency of the valve isaided by the pressure of the fuel acting thereon.

The pilot safety-control structure includes a flat strip of thermostatic metal 86 similar to that hereinabove described. The longer U-leg of the thermal strip 86 adjustably supports a screw 8'7 with its end projecting therethrough to engage the projecting end of the valve stem '79. This stem-contracting screw may be adjusted to vary the time and extent of movement of the stem 79, producing results similar to adjustment of the spool 39 of Fig. l.

As heat is applied to the thermostatic strip, the resulting motion of the metal (due to the U-shape and the differential metal arrangement) will be in a direction moving the U-arms of such strip toward each other, consequently moving the valve stem '79 against the action of spring 81 to open the valve '74 and close valve 80. As the thermal strip cools, the reverse action takes place under the control of the spring 82 and the fuel pressure normally acting on the valve '74. Other than above described the construction and operation of this form of structure is similar to that of Figs. 1 to 4, inclusive.

The operation and advantages of my invention will be readily understood from the foregoing. The pilot structure constitutes an intimate part of the burner structure whereby the action of the main burner is controlled more positively and directly in accord with conditions existent directly at the burner. The safety control feature is positive in action, and reliably responsive to all conditions. The burner may operate over long periods of time with maximum efficiency and safety, and practically without attention. The pilot flame is disposed in the combustion chamber above the comparatively wide U-bend of the thermostatic strip whereby up-drafts of air'do not materially affect such flame which burns uniformly with proper thermal-heating effect at all times. The position of the pilot flame tip structure insures a blue flame with a minimum of carbon deposit on the strip. Only a small amount of gas is required for pilot purposes.

In addition to the foregoing, my invention greatly simplifies burner equipments by reducing the number of parts and connections required; the costs of maintenance and production are lowered and the number of standard replacement parts to be carried is materially reduced. The burner structure as a whole is very compact and enables the same, with its safety features, to be mounted in small spaces, making possible the use of smaller combustion chambers which is a very desirable feature, giving the burner utility in environments where its use, otherwise, might be prohibitive due to lack of space.

It will be understood that while I have shown only two embodiments of my invention, changes in details and arrangement of parts may be made without departing from the spirit and scope of my invention asdefined by the claims which follow.

I claim:

1. The combination with a combustion chamber, of a burner comprising a body supporting one or more discharge elements which project into said chamber, and means for controlling the flc-w of fuel through said burner body to said elements which includes a pilot flame element supported by said body, a valve supported by said body, a thermostatic strip bent to a U-shape and having its inner surface formed of a metal having a low coeflicient of expansion, one end of said strip being operatively connected to said valve and the U-bend of said strip being located in the path of the flame from said pilot element to heat said strip to cause its movement to open said valve, the U-bend portion only of said strip being projected a slight distance into said combustion chamber to be subjected to radiant heat variations in said chamber to cause a breathing movement of said strip and valve.

2. The combination with a combustion chamber having a bottom with a plurality of openings therein, of a burner comprising a body located outside said chamber and supporting a plurality of discharge elements which project into said chamber through certain of said openings, and means for controlling the flow of fuel through said burner body to said elements which includes a pilot flame element supported by said body and projecting through one of said openings into said chamber, a valve supported by said body outside said chamber, a thermostatic strip operable to actuate said valve, said strip being bent to a U-shape and having its inner surface formed of a metal having a low coefficient of expansion, one end of said strip being associated with said valve outside said chamber and the U-bend of said strip being located in the path of flame from said pilot element to heat said strip to cause movement of the latter to open said valve, the U-bend of said strip also projecting through one of said openings a slight distance into said combustion chamber to be subjected to radiangheat variations in said chamber to cause a bre hing movement of said strip and valve.

3. The combination with a combustion chamber, of a burner having flame-burning elements projecting into the central portion of said chamber, means constituting a part of said burner which includes a tip member discharging a pilot flame in a zone beneath the discharge zone of said flame-burning elements, a part at least of which pilot flame is directed toward said elements, valve means controlling the flow of fuel to said burner, and thermal means under the control of the pilot flame for actuating said valve including -a flat piece of thermostatic metal having only a small portion thereof projecting within said combustion chamber and afiected only by radiant heat therein, the said portion thereof within said chamber being disposed fiatwise beneath and contacted by the pilot flame.

4. The combination with a combustion cham-' ber, of a burner having a chambered body supporting a fuel-burning element projected upwardly to discharge in the central portion of said chamber, a pilot-flame discharging device associated with said body and fed from a source of fuel for producing a pilot flame for igniting fuel discharging from said fuel-burning element, a valve wholly outside said combustion chamber and out of the direct heat zone of said fuel-burning element, a thermal element actuating said valve in one direction, said thermal element being U- shaped and having its U-bcnd portion only disposed directly in the path of said pilot flame for predetermined valve-opening movement and out of the direct heat zone of said fuel-burning element, the U-bend portion of said thermal element being positioned in the bottom portion of said combustion chamber so as to be subjected additionally to the radiant heat of said fuel burning element in said chamber to cause said thermal element to move with a breathing-like action while in its valve-opening position.

SIMON J. LONERGAN.

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