US2131221A - Burner and control unit for furnaces - Google Patents

Description

Sept. 27, 1938. H. A. CRARY 2,131,221

BURNER AND CONTROL UNIT FOR FURNACES Filed Nov. 29, 1935 2 Sheets-Sheet 1' FIG. l

20 241 32 0o O'ooooooooooo Fly- 5 3 2222222222: I Z7 I? a 6/ 30 if I 6/ 1 INVENTOR L HORACE A. CRARY A TTORNEYSY Sept. 27, 1938. H. A. CRARY 2,131,221

BURNER AND CONTROL UNIT FOR FURNACES Filed Nov. 29, 1935 2 Sheets$heet 2 l 1 Y l FIG. 4 a

n I, 4a 9 FIG-5 up o m x '1 20 /7 x HQ 6 mvnvroR HORACE A. CRARY A TTORNE Y6 Patented Sept. 27, 1938 UNITED STATES nuance.

I 2,131,221 AND con'nzgr. mmroa FURNAC Home A. Crary.

Warren, Pa., assignor to Pennsylvania Furnace & Iron C corporationof Pennsylvania 0., Warren, Pa, a

Application November 29. 1935, Serial No. 51m c Claims. (01. 158-7) This invention relates to gas fired heating apparatus, and more particularly to the burners and control devices therefor.

The object of the invention is to provide improved heating apparatus which includes an arrangement of the burners and the gas supply and control devices therefor, or at least a part of such devices, in unit form capable of convenient detachment from both the heating apparatus and 0 from the gas supply pipes, so that not only may the parts of said unit be assembled on the bench and kept in stock in unit form, but also such unit may be very readily introduced into its position in the heating apparatus with the burners in place in the combustion chamber and may be removed from such position both during initial erection or construction of the heating apparatus and later for p poses of repair, replacement or reconstruction.

A further object of the invention is to provide a unit of the kind described including all necessary parts for properly supporting the burners and for supplying secondary air and for distributing it properly to and around the burners and the jet openings.

Further objects of the invention are in part obvious and in part will appear more in detail hereinafter. Y

In the drawings, which represent one suitable embodiment of the invention, Fig. 1 is afront elevation, parts being broken out and in section to expose interior construction.

Fig. 2 is a diagram of the burners and control devices;

Fig. 3 is a sectional plan view on the line 34, Fig. 1;

Fig. 4 is a detail sectional elevation onthe line H, Fig. 3, showing the burner and control unit partly withdrawn from the casing;

to Fig. 5 is a sectional elevation on the line 5-5, Fig. 3;

Fig. 6 is a detail sectional elevation on the line M, Fig. 5; and

Fig. 7 is a sectional elevation on the line Fig. 5.

The invention may be applied to any kind of gas fired heating apparatus where gas burners operate in a combustion chamber for the pun- 0 pose of producing a heating efl'ect, such as a domestic hot water heater, a vapor, steam or hot water boiler, or the like. For convenience, and

in no sense of limitation, the drawings illustrate the invention applied to a hot air furnace 5 which may be of any suitable construction and approximately plate is formed to the details of which form no part of the present invention and require only brief description.

The'hot air furnace illustrated comprises an outer jacket or casing including .a front wall I, side walls 2, a back wall 3 and a top 4 within which is a hot air chamber 5 provided with an air inlet 6 and with suitable outlets such as conventionally illustrated at I through whichthe heated air is conducted to the place of use.

Within said casing is suitably supported the heating drum or radiator marked generally 8, usually formed, of sheet metal cut, shaped and formed to provide at its bottom a combustion chamber 9 to which secondary air'is supplied in the usual manner, such as by way of the louver openings ill in a removable door plate N forming part of the front casing wall, and which combustion chamber communicates with passages and chambers through which the heated products of combustion travel toward the stack outlet or outlets ii. In the present instance the heating radiator is vided with a series, eight being shown, of. internal passages l2 forming part of the hot air chamber 5 and through which the air to be heated travels on its way from the inlet 5 to the hot air outlets I.

In the front wall of the furnace is an opening it communicating with the combustion chamber 9 (Fig. 4) and through which opening the burners and those parts of the unit which lie within the. combustion chamber are inserted into position. This opening is closed, when the parts are assembled, by a door or plate I which may be removably secured inposition, as by bolts passing through the openings i5. This door provide the lower openings in before referred to.

of double wall form pro- Above the opening it in the front wall of -the I casing is a hinged door Ila, which may be opened at any time to provide access to the combustion chamber for any purpose, such as for igniting the burners, inspecting them or their operation or the like.

Of course, the combustion chamber and the passages through which the products of combustion travel are wholly sealed or shut off from the .hot air chamber and-passages, to wholly prevent cross communication. between them. The combustion chamber, therefore, is provided with side walls It, a backwall l1 and a bottom mn [lathe latter of which is inclined downwardly toward the front of the furnace and serves to assist in supporting the burnersarid the rear end of the burner and control unit.

The burner and control unit includes the removable door plate l4 and the parts attached to and carried thereby. These include a shallow pan-shaped member having a perforated bottom IS and side walls 20, the bottom wall I! lying at a level at or near the uppermost one of the louver openings III, as shown in Fig. 5. Projecting inwardly from the door plate l4 at the ends of the louver openings are a pair of side plates 2i located in vertical planes and somewhat overlapping the side walls 20 and extending down to the lowermost louver opening, where said side plates are provided with inturned flanges or ledges 22. At their rear ends plates 2| are connected by a cross strap 23 and are provided with feet 24 which rest and slide upon the bottom wall It of the combustion chamber, as shown in Fig. 4.

The burners 25, any number of which may be used and three of which are shown, are elongated hollow members provided with the usual raised drilled ports 25, only a few of which are illustrated for simplicity, the chamber within each of said burners communicating with the passage in a specially formed cast metal elbow 25a which forms a support for its burner. Each elbow is provided with an integral foot 21 held in place or confined within a small housing 23 made of sheet metal and fastened to the pan bottom l5. Each elbow communicates with a supply pipe 25 provided with a Bunsen mixer 35 to which gas is supplied from a pipe 3! provided with a gas cock 32 and communicating with the manifold 32a. The pipes 3i pass through openings inthe door I 4, as will be readily understood.

The burner unit also includes one or more pilot burners 33 of suitable form and including a rectangular base 34 held in a housing 35 also attached to the bottom plate l9. One of the pilot burners may also include a safety pilot burner and valve 35. These pilot burners communicate with the usual small supply pipes 31 which also pass out through openings in the door plate l4 and communicate with the control devices.

One of the burners 25, such as the middle burner in the arrangement shown. may have its supply pipe 3! connected tothe gas supplyindependently of the manifold 3l2a,'such as by way of a pipe 3|a. i

The gas supply and control devices by which gas is supplied to the pipe 3|a and manifold 32a and from them to the burners, as well as to the pipes 31 and to the various pilot burners, may be of any suitable form or description, either hand operated or controlled automatically, or a combination of both forms. Usually the control devices are at least partly automatic in the sense of being subject to emergency shut oil? by extinguishing of the pilot flame or flames or by abnormal low pressure of gas or the like, and also to variations in temperature of the device or place to be heated, such as the temperature of the water in a domestic hot water heater, the temperature of theboiler, or the temperature of a room to be heated, or by anycondition or function of the device to be heated-such as low water reference may be had for a more complete description thereofif desirable or necessary. For

the purpose of this application only brief reference to the control devices is necessary. They consist of an ordinary pressure regulator valve 45 and its diaphragm 4|, a master control valve 42 and its diaphragm 43, and a main valve 44 and its diaphragm 45. The pressure regulator valve 40 and main valve 44 are in series with each other, in the order named, in a connection from the supply pipe 45 to the manifold 32a, and in said connection "are one or more union couplings, such as the coupling 41 in advance of the pressure regulator valve and the coupling 48 between the main valve 44 and manifold 32a. This main valve 44 supplies gas to the manifold 32a and to the two burners 25 with which it is connected.

The master control valve 42 is located beyond or on the furnace side of the regulator valve 40,

Beyond the valve 42 pipe 49, in advance of valve 53, communicates with a pipe 5| which communicates with anelectrically operated thermostatic valve 52 beyond which is a pipe 53 having two branches, to-witya branch 54 communicating with an escapement pilot 55 and branch 55 communicating with the chamber beneath the diaphragm 45, pipe 5| also having a second branch in which is a gas cook 51 supplying a pipe 55 leading to the pilots 33 and the safety pilot and valve 35 and a branch 59 which su plies pressure to the chamber beneath the diaphragm 43. The upper chambers of the diaphragms 4|, 43 and 45 communicate with a vent pipe 55; All

of the small pipes leading to the pilot burners are provided with unions 5|. 52 indicates a by-pass normally closed thumb operated press button valve 53. In one of thebranches from pipe 5| at a point just beyond the valve 51 and in advance of pipes 58 and 59, is located a restricted oriflce'54'.

The operation of the control devices is as follows:

Let us assume that the furnace is out of commission, that there is a demand for heat from the thermostats controlling the valves 52 and 50, and that it is desired to put the system into operation. Button operated valve 53 is pressed to open it, which supplies gas through the by-pass 52, around the valve 42 and by way of open valve 50 to the middle burner, whose cock 32 may be assumed to be closed, the cooks 32 for the other two burners being open. Cock 51 is opened. Safety pilot 35 is provided with a thermostatic element'55 sensitive to the temperature of the pilot 33 and it, because it is cold, holds open the'valve at the safety pilot 35. Pilots 35 and 33 are'all lighted. Atiirst, because there is outflow through the two pilots 33 and the safety pilot 35, these three pilots take so much gas that the restricted orifice 54 cannot supply sufllcient gas to create pressure beneath the diaphragm 43. Finally, however, the

effect of the heat at the pilot 33 flexes the thermostatic element 65 and moves the same over to permit the valve at pilot burner 36 to close, whereupon pressure becomes effective against the diaphragm 43 to raise the same and open valve 42, so that gas flows freely through valve 42 and maintains the supply for the diaphragm 43 and holds the same elevated. The hand operated valve 63 may now be released. Pressure flowing through pipe 53 and by way of valve 52 now becomes eilective against the diaphragm 45 to raise the same and open valve 44, so that gas flows to the manifold 32a and thence to the two side burners 25, which are ignited. Cock 32 may be opened and gas will also flow to the middle burner 25.

The three burners continue in operation until the demand for heat is satisfied to an extent suflicient to cause the thermostat which controls valve 52 to close said valve, whereupon diaphragm 45 drops, valve 44 closes, and the supply to the two side burners 25 is cut oil. The

thermostat which operates valve 50 is set to be sensitive to a temperature a little higher than that which controls valve 52, say two or three degrees. Consequently, while the middle burner 25 continues to operate, if the temperature rises above the setting of its thermostat, valve 50 closes and the supply to the middle burner is also shut off.

As the temperature falls, first the valve 50 is opened and, if the temperature falls two or three degrees more, valve 52 is opened, with successive ignition first of the middle burner and then of the two side burners.

Upon emergency operation, as in case the gas pressure falls abnormally, or the pilots are blown out, the effect ultimately is to cool the thermostatic element 65 of the safety pilot, which element moves over and permits valve 36 to-. ,open, whereupon the supply of pressure to diaphragm -43 is so diminished that valve 42 closes, cutting oif the supply of pressure to the diaphragm 45 and causing valve 44 to close, whereupon the supply of gas to all burners, both main and pilot, is cut off. It is then necessary to start the system by operations as before, beginning with operation of the button valve 53,

In the arrangement shown the combined burner and control unit may be made up and kept in stock in two different forms, differing only in completeness of assembly.

Assuming that the union coupling 41 is opened or disconnected, the unit includes the door plate l4, all of the burners and parts inside of the combustion chamber, and all of the gas control and supply pipes beyond or on the furnace side of the coupling 41.

Assuming that the union coupling 48 is open or disconnected, that the several union couplings 6| are open or disconnected, and that the union coupling Gla in pipe 3| a is open or disconnected, the unit includes the door plate l4, all of the burners and parts inside the combustion chamber, and all gas supply and control parts beyond or on the furnace side of the union couplings 48, BI and Bid.

Referring to the unit in its form under the first condition stated, where said unit includes all parts beyond or on the furnace side'of the union coupling 41, the unit includes as parts of a single organized structure, all of the burners and other parts within the combustion chamber, the door plate l4, and all of the control and gas supply parts, including the several valves and their diaphragms specifically referred to, and the control and gas supply pipes connected to them and l to other control parts .as described. in the costyle or arrangement of the gas supply control unit may serve for several difl'erent shapes or styles of heating device and may be interchange-- ably fittedto one or more thereof. Therefore, the distributor in supplying an individual furnace need only select that furnace which fits the space or requirements of the job in handand attach to it from his stock a combined control and gas supply unit. The parts of the gas supply and control unit are assembled at the factory and require no special or skilled attention by laborers on the job.

Furthermore, in case any of the parts get out of order or require service or repair, simple disconnection of the unions enables the gas supply and control unitto be detached both from the gas supply pipe and from the furnace and heating device and to be removed from both so that it is readily replaced by a new unit or may be taken to the bench for repair or adjustment.-

, Again, in the initial construction of these-devices the furnace or heating device as a whole may be constructed on the floor while at the same time the gas supply and control unit is being assembled and adjusted on the bench, with-the ability to use for the two assemblies skilled labor best fitted to the respective tasks.

Referring now tothose parts of the unit which are contained within the combustion chamber, it will be observed that the arrangement provides for convenient insertion of the parts into position. The rear end of the unit consists of the rearwardly projecting ends of the burners 25 and of the walls of the pan beneath them, all of which lie, considerably above the lower edge of the door plate l4. It is therefore a simple matter to introduce the rear end of the unit into the opening I3 and to push it back into place. During such motion the feet 24 ride up along the inclined bottom wall IQ of the combustion chamber until the parts come to the home position in which the door plate I4 is firmly fastened in place by its securing bolts. When the parts are in their final position and in operation, secondary air is supplied through the louver openings l beneath the pan-shaped member and is conducted rearwardly between the side plates 2| and permitted to flow upwardly to the burners. This secondary air passes through I the perforations or openings in the bottom plate l9 and is thus distributed to all of the burners 25 and to the spaces between said burners and further, passes up between the side walls 2| and 20 where they overlap each other, as shown in Fig. 6, so that a wall of upwardly moving fresh air is provided along the outside edges of the outside burner members. This insures very thorough and even distribution of secondary air to all of the drilled burner ports with very efficient combustion. At all times access to the burners while in the combustion chamber is afforded through the hinged door Ila What I claim is:

1. Apparatus of the character described, comprising a casing provided with a combustion chamber having an openin and with a burner said opening, burners supported by and on one side of said closure. gas supply and control de-' vices supported by and on the other side of said closure, said closure, burners and devices being secured together and being removable as a unit supported by and on the other side of said closure, said closure, burners and devices being secured together and being removable as a unit from said casing, said closure being provided with secondary air openings, and said unit ineluding a perforated horizontalwall beneath the burners upon which they are supported and through the perforations of which the secondary air passing through said closure is distributed.

3. Apparatus of the character described, comprising a casing provided with a combustion chamber having an opening and with a burner and fuel control unit including a closure for said opening, burners supported by and on one side of said closure, gas supply and control devices supported by and on the other side of said closure, said closure, burners and devices being secured together and being removable as a unit from said casing, said closure being provided with secondary air openings, and said unit including a perforated horizontal wall beneath said burners upon which they are supported and through the perforations in which the secondary air passing through said closure is distributed and vertical walls extending upwardly at the sides of said horizontal wall for directing secondary air along the sides of said burners.

4.Apparatus of .the character described, comprising a casing provided with a combustion chamber having an opening and with a burner and fuel control unit including a closure for said opening, burners supported by and on oneside of said closure, gas supply and control devices supported by and on the other side of said closure, said closure, burners and devices being secured together and being removable as a unit from said casing, said closure being provided with openings for secondary air, said unit also including a horizontal rearwardly extending perforated wall mounted on said unit above said openings and belowthe burners for supplying secondaryair, between the burners, and said unit further including walls extending, upwardly at the sides of the burners for directing secondary from said casing, said closure being provided with" openings for secondary air, a horizontal rear-.-

yrardly extending perforated wall supported by the closure above said openings and below the burners for distributing secondary air, and vertical walls extending upwardly at the sidesof said perforated horizontal wall to, distribute secondary air along the outer-sides of said burners.

6. Apparatus of the character described, comprising a. casing provided with a combustion chamber having an opening and with a burner and fuel control unit including a closure for said opening, burners supported by and on one side of said closure, gas supply and control devices supported by and on the other side'of said closure, said closure, burners and devices being. securedtogether and being removable as a unit from said casing, said closure being provided with openings for secondary air, said unit including a horizontal perforated wall extending rearwardwith a foot member entering and held in one of said pockets. 1

HORACE A. CRARY.

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