US2655987A - Combination oil-gas fired conversion burner - Google Patents

Description

Oct. 20, 1953 E. A. NORMAN, JR

COMBINATION OIL-GAS FIRED CONVERSION BURNER Filed Nov. 22 1950 2 Sheets-Sheet l INVENTOR Edward .14. 11 67771071 BY I ATTORNEY Oct. 20, 1953 NORMAN, JR 2,655,987

COMBINATION OIL-GAS FIRED CONVERSION BURNER Filed Nov. 22, 1950 2 Sheets-Sheet 2 5s 5 4 Ill;

"5 W 79 am; 631 7 49 78 3| is as 23 83 l 82 INVENTOR.

ATTOR N EY Patented Oct. 20, 1 953 UNITED STATES PATENT 2,655,987

COMBINATION OiL -GAS FIRED CONVERSION BURNER Edward A. Norman, In, Columbus, Ohio, assignmto Norman Products Company, Columbus, Ohio, a corporation of Ohio Appiieation November 22, 1950, seriai No. 197137? 5 Claims. 1

The present application is a continuation-4m part of my previous U. S. patent application Serial Number 50,103, filed September 20, 1948, entitled Combination Oil-Gas Fired Conversion Burner, and now abandoned.

This invention relates to conversion burners of the type employed in furnaces for the burning of fluid fuels in lieu of coal or other solid fuels. Such conversion burners heretofore have been of operation of the burner from one of said fuels to the other. i

A further obj-ectis to provide a dual fuel humor of the character indicated in which the controls are such that in the event pressure of gas suptwo general types: lied to such a burner should fail or diminish to 7 an undesired exten provision is made for shut (130031102; lfilllZlIlg normally gaseous hydrocarting p gthe p y' f a e i gyme (2) Those utilizing normally 1i qui d hydrocari galeratlon of the burnei for the consumption of bons. I 5 A still further object of this invention is to Both of these fluid fuels lend themselves readily provide acombination oil-ga fired burner of the to automatically controlled burner mechanisms forced draft type which embodies an electrically and are widely used in the heating industry. controller damper or valve mechanism operable Both types of burners, however, have their limiautomatically to vary the flow of combustion air tations. For example, an oil burner usually re to the associated fuel burner in response to a quires a storage tank for the liquid fuel which change from one fuel to another, and which, inrequires replenishment from time to time. It is the event of a failure within its operating on not uncommon for such oil supplies to become cuit, automatically opens to assure the passage exhausted and the operation of the associated of sufiioient quantities of combustion air to the burner thereby arrested before the owner or op 5 burner necessary to sustain complete combustion erator has knowledge of the deficiency. of either type of fuel.

In a gas fired burner, during periods of cit Other object are to provide a burner mocha-'- tremely cold weather, it is also not uncommon nisni for the consumption of both oil and gas for gas pressure in municipal mains to drop to as fuels and in which the oil is adapted to be levels making gas burner operation ineflicient or contained in a storage tank or vessel and where'- ineffective, or, in some instances, causing 001m in provision is made for automatically delivering plete curtailment. Also, it is sometimes difficult gaseous fuel to the burner mechanism when the under present day conditions to obtain from nor oil level within the storage tank or receptacle mal supply sources one or the other of these two recedes to a predetermined low 1evel, whereby to fluid fuels. sustain the operation of the burner mechanism Again, it is often advantageous from an ecowithout interruption; to provide acontrol sysnomic standpoint to use one of said fuels under tem for the burner of the type set forth in which conditions requiring limited heat production, and the use of the particular fuel is automatically the other of the fuels when heat requirements responsive to temperatures prevailing exteriorly' are more severe. For example, in certain dis- 0 of a building in which theburner mechanism is tricts, gaseous fuels are more expensive than used, whereby in periodsof cold weather oil may liquid fuels, and, therefore, it is an object of the be employed as the fuel for the burner and in present invention to provide a combined gas and milder weather, gas may be utilized, thus adapt= oil burner in which provision is made for shifting ing' the burner for economy in fuel consumption automatically from one to the other of the said and with satisfactory heat production. fuels to meet most economically and advan- For a further understandingof the invention, tageously various demands for heat production. reference is to be had to the following descrip It is another object of the present invention tion and the accompanying drawings, in which: to provide a fluid fuel burner which utilizes ad- Fig. 1 is a top plan view of a fluid fuel burner vantageously normally gaseous or liquid hydrO- mechanism constructed for the use of both gasecarbons as fuels, so that if for any reason one of ous and liquid fuels; g such fuels should not be readily obtainable, the Fig. 2 is a vertical longitudinal sectional view other may be employed to maintain efficient taken therethrough; burner operation. Fig. 3 is a diagrammatic view disclosing the It is another object of the invention to proautomatic controls of the burner mechanism for governing fuel selection in a manner based on variations in outside air temperatures;

Fig. 4 is a similar view disclosing the control arrangement for the automatic selection of fuels based on variation in gas supply pressures; and

Fig. 5 is also a diagrammatic view disclosing the control arrangement for the dual fuel burner in which gas is supplied when a predetermined low oil level is reached in an associated storage tank.

Referring more particularly to the drawings, the numeral designates the improved multiple fuel consuming conversion burner comprising the present invention. In this instance, the same embodies a burner .vessel l! which is adapted to be positioned in the combustion chamher, not shown, of an associated furnace. Exteriorly of the furnace, the burner mechanism embodies a housing E2, the latter being' joined with the vessel H by means of a forced air duct H3. The vessel H is of the so-called pot type, and, conveniently, the same may be formed to comprise a cast bottom member Hi and an upstanding annular side wall It, the latter being provided with a multiplicity of perforations l5 admitting of the flow of air into the interior of the vessel from the duct I3. The duct 13 is normally supplied with air by means of a fan or blower I? driven by an electric motor 18 and mounted within the housing i2. lhe duct 13 at 1 its forward end terminates in a shell it in which the vessel H is positioned, with the bottom and side walls l4 and I5 of the vessel spaced from that of the shell, whereby to provide for air circulation or passage therebetween.

Oil under gravity flow, usually from a storage tank, is transmitted to the housing !2 by way of the oil inlet pipe it. This pipe extends to a control valve and oil level establishing unit 2i of well known construction, the unit involving a solenoid 22 for the operation of an associated flow-controlling valve member 23. When the solenoid is energized, the valve member is actuated to admit of the passage of oil through the unit 2! in metered quantities.

From the unit 2|, the oil travels under gravity flow by way of a pipe line 24 to a strainer unit 25 which is carried by a straight pipe member 26 disposed so that it extends from the housing [2 through the duct i3, and through the side wall of the vessel i I at the bottom thereof. The oil collects in the form of a film or shallow pool on the upper surface of the bottom member Id of said vessel where it is vaporized and admixed with air entering the vessel by way of the perforations it in the side wall i5, producing a combustible mixture which, when ignited, provides a controlled flame issuing from the open top of said vessel.

The 'fan or blower il is preferably of the continuously operating type; hence the present invention provides a movable valve or shutter means for regulating the volumes of air flowing through the duct it in accordance with the type of fuel being burned in the burner I I.

As shown in Fig. 3, there is provided in the entrance end of the duct l3, which is in direct communication with the outlet of the fan or blower IT, a vertically swinging shutter 2'] which may be in the form of a plate or panel. The shutter, when occupying its full line position as shown in Fig. 3, opens the duct to permit substantially unrestricted flow therethrough of air from the fan to the burner pot l l to sustain complete combustion of oil fuel. However, when 4 the shutter is swung to assume its dotted. line position as shown in Fig. 3, the amount of air flowing into the duct is reduced in accordance with the predetermined amount of air necessary to sustain complete combustion of gaseous fuel.

It is preferable that the shutter be operated automatically, and to this end, the shutter carries a rock shaft 28 which is rotatably journaled in openings provided in the walls forming the entrance end of the duct. At one end the rock shaft 28 terminates exteriorly or" the duct in a crank extension 29, and the outer end of this extension is disposed in contact with a laterally directed lip 38 provided on a substantially circular bimetallic strip 3!, the latter having one end thereof fixed to a bracket 32 supported exteriorly on the inlet end of the duct. In close thermal proximity to the bimetallic strip, there is mounted a coiled resistance-type electric heater 33 which, when energized, liberates heat which is absorbed directly by the strip 35. The arrangement of the bimetallic strip 3| is such that when the strip is heated, it expands causing the lip 33 to move in a clockwise direction, as viewed in Fig. 3. The shutter 2? is of the over-balanced type so that the same will automatically swing toward an open position as the lip 3t moves in a counter-cloclrwise direction upon cooling of the strip 3i, allowing virtually unrestricted air flow through the duct l3. When the coil 33 is deenergized so that the strip 35 cools, with the lip thereof turning in a counter-clockwise direction, the shutter swings by gravity to its open position permitting substantially unrestricted air flow through the conduit or duct i3.

An adjustable set screw 35 may be arranged in a position to limit upward movement of the lip 3t and the extent of closure of the shutter 2?. 7 As will be later explained, the heating coil 53 is arranged in a control circuit governed by a thermostatic switch, or other equivalent operating means, so that the supply of combustion air to the burner vessel may be increased or diminished in accordance with the particular type of fuel being burned in the vessel.

Extending into the housing [2 is a gas supply line 35. Within the housing, the line 35 communicates with a gas flow controlling unit 35, which may be any one of a number of commercial types now available, but which, in this instance, employs a solenoid 3'? for actuating a movable valve member 38 by which gas flow through the unit 36 is regulated. The gas discharge side of the unittfii includes a pipe line 39 which leads to an elbow 4t, and from this elbow a rigid pipe M extends through the duct E3 in an upwardly directed angle with respect to the horizontal, the discharge end of the pipe at being extended through the side wall of the vessel 5 l and turned downwardly, at tie, to direct gas downwardly across the bottom wall of the burner vessel. Gaseous fuel thus delivered to the interior of the vessel ii is commingled with combustion air delivered into the vessel through the wall perforations it, producing a combustible mixture which burns with an observable flame combustion at the top of the vessel. I

A pilot burner supply line 32 terminates at its forward end in a downwardly directed nozzle 43 which is disposed within the burner vessel H. Either oil or gas may be introduced into the pipe line in quantities suiiicient to maintain contmuously pilot combustion at the nozzle 43. f ab the p pe line 52 passes through a tube 44 which is disposed in the duct [3 and is supported at its ends by the walls of the housing [2 and the burner vessel ll so that air flows through the tube 44 under atmospheric pressures or furnace draft conditions in a manner uninfluenced by the fan or blower ll. The nozzle 43 may be angularly disposed downwardly and inwardly of the vessel so that the pilot flame sweeps across the bottom wall M of said vessel. The casing of the fan or blower ll includes air inlet openings 55, as shown in Fig. 2, and these openings are variable by means of an adjustable rotating valve device 46. The front of the housing l2 at the bottom thereof is provided with an opening 47 admitting of ready flow of atmospheric air into the housing and rendering accessible the fuel-controlling units.

In Fig. 3, a circuit arrangement is provided by which the shift in the use of either gaseous or liquid fuels is effected in accordance with temperature conditions prevailing exteriorly of a building heated by the burner mechanism. Thus in periods of extremely cold weather, better heating results may be obtained through the use of oil as a fuel, whereas during periods of relatively mild weather, it may be preferable to use gas as the fuel, or vice versa, depending on various considerations such as costs and the availability of the two fuels. In the form of the invention illustrated in Fig. 3, conductors 48 and 49, joined with a source of electric current supply, such as the ordinary household circuit, have connected therewith branch conductors 53 which lead to the windings of the fan motor It. In this instance, the conductors l8 and 69 extend to the primary windings 52 of a transformer 53. From the transformer 53, a conductor 54 extends to the movable bimetallic arm 55 of a room mounted thermostatic switch 56. The arm 55 is so constructed that when the room atmosphere in which the thermostatic switch is disposed cools to a predetermined level, the free end of the switch arm 55 will be flexed in a direction bringing said arm into engagement and circuit-completing relation with a contact 57 of said switch. From the contact 51, a conductor 58 extends to an outside air thermostatic switch 59. This switch includes a movable temperature-responsive switch arm 50, the latter being connected with the conductor 58, and a pair of spaced contact points 5! and 62. The switch arm Ell is normally arranged to engage the circuit contact 62 during normally mild weather when it is desirable to operate on gas fuel, but is movable,

in response to the attainment of a predetermined low temperature, into engagement with the contact terminal 6| to shift to oil consumption, as shown in Fig. 3. From the terminal 62, a conductor 63 leads to the winding of the solenoid 3'! of the gas) valve flow-controlling unit which, in turn, is connected with the secondary winding of the transformer by way of the leads E i and 65, thereby providing for energization of the solenoid 3'! so that its valve member 38 is elevated or unseated to provide for gas flow through the unit 3t and thence to the burner vessel when the arm S9 is in contact with the terminal 62. From the contact terminal 62, a conductor 65 leads to one side of the heater coil 33 which has its opposite side connected with the lead 65 connected to the secondary winding of the transformer 53.

By this arrangement, the burner mechanism normally functions on gas as its main fuel. However, if the temperature of the outside air 6. drops below a given point, the switch arm 60 moves out of engagement with the contact terminal 62 and into engagement with the contact terminal 6|. This deenergizes the solenoid 31 of the gas valve and enables current to flow from conductor 58 through switch arm 60, terminal 6|, and through a conductor 81 to the winding of the solenoid 22 of the oil flow-controlling valve, moving the valve member 23 to an open position for oil now after gas flow has been discontinued by the deenergizing of the solenoid 31. In this manner, there is an automatic shift from the use of gas as the burner fuel to that of oil,- enabling the burner operation to be sustained without attention on the part of an operator or attendant.

Fig. 4 of the drawings discloses an operating circuit in which provision is made for shifting the operation of the burner from gas consumption to oil consumption automatically in the event that the pressure of the gas supply falls below a predetermined low level. It sometimes happens in periods of cold weather, particularly when gas consumption reaches high figures, that the gas supplies of public utilities companies or municipal mains decrease as a result of peak demands and the normal gas pressures consequently drop to such a degree that gas burners cannot supply heat in suflicient quantity for normal house-heating purposes. In Fig. l, the outside air thermostat switch of the circuit shown in Fig. 3 is replaced by a gas pressure-responsive switch 68 which is connected, by way of a con duit 89, with the gaseous fuel supply main, not shown. The switch 68 is provided with a substantially closed chamber-forming casing It in which is positioned a flexible diaphragm H. The diaphragm ll carries an exteriorly extending rod 72 which is connected with a switch arm 13. The switch arm 13 is electrically connected with the conduit 58 in series with the room thermostatic switch 56. At its open end, the switch arm is movable between the circuit terminals El and E2 to control the energization of the solenoids 22 and 3? and resistance heater 33. The rod 12 and diaphragm ll are urged against the pressure of gas in the conduit 89, as by means of a spring 14, to a position establishing an operating circuit to the solenoid 22 of the oil flowcontrolling valve 23. So long as gas pressure within the conduit 69 remains at a level to sustain burner operation and eflicient heating, the diaphragm H is flexed outwardly in opposition to the spring 74, as shown in Fig. 4, to maintain an operating circuit for the solenoid 37 of the gas valve 33, but should the gas pressure drop below a predetermined level, the pressure-responsive switch 63 immediately shifts the switch arm 13 into contact with the terminal 6| associated with the oil supply valve 23. As in the operating circuit shown in Fig. 3, the resistance heater 33 controlling the operation of the damper or shutter 21 is energized concurrently with the energization of the gas solenoid 51.

Fig. 5 of the drawings discloses still another modification of the operating circuit of the present dual fuel burner. The circuit of Fig. 5 is identical to that of Fig. 3 with the exception that a float controlled oil level switch 15 is connected in series with the solenoids 22 and 31 so as to automatically shift from oil consumption to gas consumption in the event that the supply of oil falls below a predetermined level. The float controlled switch 15 comprises a movable switch arm 16 which is electrically connected with the lead 6? extending from the terminal 6! of the outside air thermostat 59. The switch arm 76 is carried upon an arm 1'! which supports a buoyant float '53 arranged within the oil tank or sump reservoir of the oil supply circuit. The switch arm 16 is movable between a pair of contacts '19 and 80 to control the energization of the respective solenoids 22 and 31. So long as the level of oil remains suf'icient to sustain burner operation, the switch arm 16 is held in engagement with the contact 79 which is connected by way of a lead 6] with the solenoid 22. Thus, as the outside air thermostat 59 shifts to oil operation in response to the attainment of a predetermined low temperature, the float controlled switch 75 is brought into play. So long as the float controlled switch is in engagement with the terminal 79, the burner will operate on the oil fuel cycle. However, should the oil supply drop below a given level, the buoyant float member 78 is arranged to swing the switch arm 16 into engagement with the second terminal 89 which is connected by way of a lead 82 with one side of the solenoid 31, in order that the burner operation may shift once again to the gas cycle until the level of oil is replenished. The lead 66 associated with the resistance heater 33 is connected, as at 83, with the leads 82 and 63 in order that the resistance heater may be energized concurrently with the energization of the gas solenoid 37.

From the foregoing, it will be apparent that the present invention provides a burner for fluid fuels and associated controls by which the burner may employ and operate successfully on either oil or gas. As above indicated, such an arrangement offers under present day conditions very definite advantages in burners utilizing fluidic fuels. It has been discovered that the hydroxylating or pot-type burner heretofore employed exclusively with the use of oil or other similar liquid fuels lends itself quite readily to use also with normally gaseous hydrocarbons. In this manner, virtually two burners are com bined in one with but slight, if any, additional costs in manufacture. By so combining in one burner the features of dual fuel consumption, many advantageous features of automatic control in the operation of the burner are made possible in its adaptation to fuel economies, outside Weather conditions, and sustained operation.

The apparatus is, of course, subject to certain variation and modification with respect to that disclosed herein without necessarily departing from the spirit and scope of the following claims.

I claim:

1. A combination oil and gas-fired conversion burner comprising a vertically arranged openmouth burner vessel having perforate side walls; an ii perforate casing surrounding the side walls of said burner vessel and arranged to be positioned within the combustion chamber of a normally solid fuel-burning furnace; a substantially horizontally arranged air duct communicating at one end with said casing and arranged to extend outwardly and exteriorly of a furnace in which said casing is positioned; a blower communicating with the opposite end of said duct for supplying forced air to said casing and to said vessel by way of the perforate side walls thereof; damper valve means including a shutter insaid duct movable between positions permitting of free or restricted flow of air through said duct, said shutter being movable by gravity to a position permitting free flow of air through said duct; electrically actuated means engageable with said damper valve means and energizable to move the shutter to a position restricting the flow of air through said duct; a liquid fuel supply conduit communicating with said vessel; a separate gaseous fuel supply conduit communicating with said vessel; a pilot burner positioned in said vessel for directing a pilot flame downwardly against the bottom thereof and for igniting liquid or gaseous fuels introduced to said vessel by way of said fuel supply conduits; electro-responsive valve means connected with each of said fuel supply conduits and energizable to permit the free passage of fuels through said conduits and to said vessel; and switch means having electrical connections respectively with each of said electroresponsive valve means and with said electrically actuated means and operable selectively to close an operating circuit for either of the electro-responsive valve means while opening an operating circuit for the other of said electro-responsive valve means, and for closing an operating circuit for said electrically actuated means simultaneously with the closing of an operating circuit for the electro-responsive valve means associate\ with said gaseous fuel supply conduit only, whereby to move said shutter to a position re stricting the flow of air through duct upon introduction of gaseous fuels within said burner vessel.

2. A combination oil and gas-fired conversion burner comprising a vertically arranged openmouth burner vessel having perforate side walls; an imperforate casing surrounding the side walls of said burner vessel and arranged to be positioned within the combustion chamber of a normally solid fuel-burning furnace; a substantially horizontally arranged air duct communicating at one end with said casing and arranged to extend outwardly and exteriorly of a furnace in which said casing is positioned; a blower communicating with the opposite end of said duct for supplying forced air to said casing and to said vessel by way of the perforate side walls thereof; damper valve means including a shutter in said duct movable between positions permitting of free or restricted flow of air through said duct, said shutter being movable by gravity to a position permitting free flow of air through said duct; electrically actuated means engageable with said damper valve means and energizable to move the shutter to a position restricting the flow of air through said duct; a liquid fuel supply conduit communicating with said vessel; a separate gaseous fuel supply conduit communicating with said vessel; a pilot burnor positioned in said vessel for directing a pilot flame downwardly against the bottom thereof and for igniting liquid or gaseous fuels introduced to said vessel by way of said fuel supply conduits; electr c-responsive valve means connected with each of said fuel supply conduits and energizable to permit the free passage of fuels through said conduits and to said vessel; a first switch means responsive to the temperature of a zone to be heated by said burner for establishing an operating circuitfor said electro-responsive valve means and said electrically actuated means; and other switch means connected in series with said first switch means and having electrical connections respectively with each of said electro-responsive valve means and said electrically actuated means and operable for selectively closing simultaneous operating circuits for said electrically actuated means and the electro-responsive Valve means associated with said gaseous fuel supply conduit while opening an operating circuit for the electroresponsive valve means associated with said liquid fuel supply conduit, or for closing an operating circuit for the electro-responsive valve means associated with said liquid fuel supply conduit While opening operating circuits for said electrically actuated means and the electro-responsive valve means associated with the gaseous supply conduit, whereby to control the position of said shutter so as to provide increased air flow through said duct upon supply of liquid fuel to said burner vessel.

3. A combination oil and gas-fired conversion burner as defined in claim 2 wherein said lastnamed switch means comprises a thermostatic switch responsive to temperatures outside the zone to be heated by said burner for automatically closing an energizing circuit for the electro-responsive valve means associated with said liquid fuel supply conduit and for opening an operating circuit for the other of said electro-responsive valve means and said electrically actuated means in response to a predetermined low temperature of said outside atmosphere.

4. A combination oil and gas-fired conversion burner as defined in claim 2 wherein said lastnamed switch means comprises a pressure-actuated switch responsive to a predetermined low pressure of gaseous fuel within said gaseous fuel supply conduit for opening an operating circuit 10 for the electro-responsive valve means associated with said gaseous fuel supply conduit and for closing an operating circuit for the electro-responsive valve means associated with said liquid fuel supply conduit.

5. A combination oil and gas-fired conversion burner as defined in claim 2 in combination with a liquid fuel reservoir connected to supply fuel to said. liquid fuel supply conduit, and wherein said last-named switch means comprises a float-actuated switch responsive to a predetermined low level of fuel within said reservoir for opening an operating circuit for the electro-responsive valve means associated with said liquid fuel supply conduit and for closing an operating circuit for the electro-responsive valve means associated with said gaseous fuel supply conduit.

EDWARD A. NORMAN, JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,752,727 Breese Apr. 1, 1930 1,840,744 Scott Jan. 12, 1932 1,860,311 Klees May 24, 1932 1,885,478 Powers Nov. 1, 1932 2,364,591 Stcughton et a1. Dec. 5, 1944 2,552,302 Young May 8, 1951

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