US2253160A - Apparatus for automatically controlling feed of fuel to burners or furnaces - Google Patents

Description

g- 1941- P. s. ARNOLD APPARATUS FOR AUTOMATICALLY CONTROLLING FEED OF FUEL TO BURNERS OR FURNACES Ongmal Flled Apr1l 16, 1934 2 Sheets-Sheet 1 ATTORNEY.

'Aug. 19, 1941. P. s. ARNOLD APPARATUS FOR AUTOMATICALLY CONTROLLING FEED OF FUEL TO BURNERS 0R FURNACES Original Filed April 16, 1934 2 Sheets-Sheet 2 W-EI M- IIIIIIIIIII/IIIIIIIIJ Willi/Il Patented Aug. 19, 1941 i APPARATUS ron AUTOMATICALLY CON- raoumc ,FEED or FUEL T BUR-NEBS on FURNACES Philip s. Arnold, Flint, Mich.

'orlgina l application April 10, 1934, Serial No.

Divided and this application Septembe! 9, 1939, Serial No. 294,170 3 Claims. (Cl. 158-28) This invention relates to apparatus for automatically. supplying and for controlling the volume of flow of fuel per unit of time to a burner or furnace and is a division of my U. S. application for patent, Serial No. 720,826, for Fuel burner, filed April 16, 1934.

The object of the invention is to provide a nozzle for the discharge of hydro-carbon fuel into a combustion chamber in association with means for providing air under pressure to the nozzle to cause the liquid fuel to discharge into the combustion chamber in atomized form, and a pressure actuatable device connected with the air line for maintaining flow of fuel under pressure and a temperature controlled apparatus to vary pressure in the air line to correspondingly varythe volume of fuel discharged per unit of time in correspondence with variation in at-' mospheric temperature.

These and other objects and novel features of the invention are hereinafter more fully described and claimed and a burner or furnace embodying my invention is shown in preferred form in the accompanying drawings in which- Fig, 1 is an elevation showing my improved burner as applied to a domestic heating furnace.

Fig. 2 is an enlarged vertical section of the burner proper and the associated control devices.

Fig. 3 is a section of the combustion chamber taken on line 3-4 of Fig. 2.

Fig. 4 is a section taken on line l4 of Fig. 2 showing the safety control.

Fig. 5 is a section similar to that shown in Fig. 3 showing an alternative form of construction of the combustion chamber at the point of introduction of the fuel.

Fig. 6 is a similar view of another form of construction of the combustion chamber.

Fig. 7 is a longitudinal section of a convenient form of atomizing nozzle.

In Figs. land 2 is shown a preferred form of the construction and arrangement of the burner and the means for supplying air and oil under pressure thereto, the burner being housed in the casing indicated at I and to this casing is connected a conduit 2 opening to the exhaust flue 3 through the radiator, firepot, grate, ashpit, and thence out through an auxiliary flue I which is here shown as discharging into the exhaust flue 2 adjacent the stack (not shown) in the wall 8. The heating of these usual channels for heated gases in a hot air furnace heats the air in the exterior shell of the furnace and this heated air passes through the usual flues 9, 9 to the rooms of a building to be heated. The casing I having my improved burner may be formed of any approved material, preferably metal, and the exterior thereof may have an insulatingcovering Ia particularly about that portion thereof immediately surrounding the combustion chamber II to prevent material loss of heat to atmosphere.

The combustion chamber H is preferably formed of a refractory material and the bottom section thereof, indicated at I2: is greater in diameter than the body I3. The bottom wall of the chamber is provided with a series of apertures I 4 for inflow of air and the side walls of the bottom portion I2 are provided with the tangential apertures IS. The body of the chamber above the bottom wall has apertures l8, preferably tangential, opening therethrough. There are also a series of air inlet holes I'I at the open upper end I8 of the combustion chamber II. This end It closes the interior of the casing I to the conduit 2 so that air inthe casing must pass into the combustion chamber to complete combustion. The flue 2, valve 5, and the walls of the tube 3 to the point of entrance into the combustion chamber and channel 6 of the furnace are lined with a fire resistant material indicated at I9. To the bottom wall of the combustion chamber ii and adjacent the nozzle 22 is connected a fuel pipe 20 having a valve 21 for control thereof to provide a pilot light. Liquid or other form of fuel in atomized condition isdischarged through the nozzle 22 into the bottom section I2 of the combustion chamber as shown in Fig. 3 from which it will be observed that the atomizing nozzle by discharging the fuel stream tangentially into the chamber causes the supplied fuel to pass circumferof the furnace indicated generally at l. A valve 5 is provided in the flue 3 which; when in the open position as shown in Fig. 2, directs the gases in my arrangement, these gases pass downward Jet. l I

d The atomizing nozzle is shown generally in Fig. 7 and is a common form of structure having an exterior shell 24 through which air under high pressure is fedTrom the pipe 25 and within this member 24 isthe terminal portion 28 of the oil supply pipe'fl. The discharge and 28 of the pipe 25 is of a smaller diameter and terminates at the opening 29 of the shell 24 through which air flows parallel to the end of this tube and past the button 30 to produce spray. This is a common form of atomizing nozzle and other forms of nozzles adapted for the purpose may be utilized if desired without departing from the spirit of this invention.

In the form of construction of the bottom section of the combustion chamber shown in Fig. 5,

a single nozzle 22a may be employed discharging centrally between two circular portions providing chambers SI and Sla. In either of these chambers shown and in any form of the combustion chamber the apertures l5 for inflow of air into the fuel stream should extend practically tangentially through the wall or at least at a material angle to a radial line of the circular chamber and in a direction to permit air to pass into the chamber in approximately the direction of flow of fuel discharged by the nozzle.

Thus the inflow of air tends to accentuate the rotation of the gaseous body in combustion and preferably in any oi the constructions of the combustion chamber shown, the wall, as the wall 34 shown in Fig. 2, between the body and the bottom section or chamber I2, is inclined or so con.- structed as to tend to .delay movementof the gases in combustion axially through the body oi the burner. I

Ignition of the fuel takes place in this bottom section and the inflowing fuel body is raised.in temperature to above the combustion temperature. To continue the combustion, the openings ii are provided in the body in order to discharge air into the gases in passing upwardly toward the exhaust flue 3 of the furnace. Air passing through these apertures I4, l5, l6 and I! in the form of combustion chamber shown in Fig. 2 is provided by a fan 35 which is positioned above a dividing wall 36. in the casing I and takes its! supply through an aperture 31 opening to the lower chamber 38 of the member I. The chamber 38 is open at its bottom to atmosphere through a a conduit 39 having a valve 40 for varying the area of the opening, the control of which is hereinafter described. The fan 35 is driven by a motor 4| supported on a base 42 suspended from the dividing wall 36 by the studs 43.

For supplying air under pressure to the nozzle. I provide a two-cylinder compressor supported from the base 42 on which the motor is mounted ing for the motor shaft. The pistons have the usual spring valve in the outer end which opens on the instroke of the piston and closes on the outgoing stroke and the head of the cylinders is formed with an aperture 5| covered by a recessed plate 52. An aperture 53 is provided from the recess of this plate to the interior of the chamber 44;. Thus the air is taken from the interior 34 of the casing i in which the compressor is mounted through the motor 4| and through apertures 4| a in the base 42 and is discharged into the chamber 44 and thus the oil in the said chamber is under pressure and is caused to lubricate the bearing for the motor and compressor. This oil under pressure may, by a conduit (not shown), lead to any part of the apparatus which requires to be oiled.

The chamber 44 acts as a storage tank for air under pressure and the air line 25 has its intake end in this chamber above the oil surface and upturned as shown..to prevent any material amount of oil entering the same. As before described, the air line 25 opens to the nozzle as shown in Fig. 7. The oil line 21 has a constant level chamber 54 and leads to the atomizer or nozzle as indicated in Fig. 'l. The compressor may be of any type providing for substantially constant air pressure. v

The control of the burner in operation is accomplished by the following described mechanism:

Connected into the fuel supply pipe 21 is a control valve 55 and this valve has a stem 55 connected to a lever 51 hinged at one end to a diaphragm casing 58 and the opposite end of the lever 51 is connected by means of a lever 49 with the valve 40 controlling the air inlet to the casing through which the fan 35 is supplied. The lever 51 has a spring 60 tending to close the fuel valve 55 and also to restrict the air opening through the turning of the air valve 44. The lever also has a bearing 51a. opposite the pivotal connection with the oil valve 'stem 56 engaging the flexible diaphragm 6i forming one wall of the casing 58. The chamber of the casing 58 is connected to the ail line 25 by a pipe 58a through which air under pressure is supplied to automatically open the valve and permit flow of oil. Thus'it will be observed that the 'oil valve 55 and the valve or shutter 40 may both be operated or adjusted in unison and the proper proportion of the air and oil are admitted to the combustion chamber Ii for accomplishing complete combustion. The construction shown in Fig. 2 is an arrangement adapted for use with oil or gas as a fuel. With a powdered fuel some change in construction of the valve would be required but the relationship of the parts would be substantially the same. I,

The compressor preferably has a constant output greater than is required by the atomizing nozzle or nozzles and to control the operation of th burner, I provide a thermostat. indicated generally at 82, which maybe located at any convenient point of the building or space to be heated. The thermostat consists of a bimetai helix 63 for operating a needle valve 64 normally closing the opening to a conduit 85 connected with the air line 25 here shown as being connected to the line 25 through the conduit 58a for the diaphragm chamber. Due to an excess temperature in the heated space the thermostat opens the conduit 65 permitting escape of air, thereby reducing the pressure in the diaphragm chamber 58 permitting the lever to act under tension of the spring 50 to partially close the valve 55. Under the opposite condition, that is. a reduction in temperature of the heated space, the helix operates to close the needle valve I4 N to a greater extent and also opening the valve or shutter at "to increase the air flow to the fan I! and thus increasing the heat output of the burner. I

There is an additional safety control shown generally at 68. This. as shown in Figs. 2 and 4. co sts of a bimetal helix Ila mountedrigidly at on eind on the end of a tube 81 which is screwed into an aperture provided in the radiator ring or channel of the furnace and attached to the inner end of the helix and extending out through the tube II is a shaft II on the outer end of which is mounted a disc ll having a notch II in its periphery.

If at any time the fire in the combustion chamber goes out. the helix in the radiator ring is allowed to cool and thus rotate the disc It to bring the notch ll opposite the pin permitting the lever to be moved by a spring 11 to open the valve 14 releasing the air pressure and closing the fuel valve. Flow of raw oil into the combustion chamber is thus prevented.

When the temperature of the helix is not increased by combustion gases passing through the radiator ring from the combustion chamber II the disc rests in such a position that a pin ll mountedon the end of a pivoted lever I2 is held in the notch by tension of the spring 11. The lower end of thelever I2 is connected by a link 13 with a needle valve I4 having a stem riding in a guide 15. The valve may seat in the end of the tube 18 connected with the air supply pipe Ila and thence with the main air supply pipe -25. The toggle structure consisting of the lever I2 and link II, is so arranged that when the pin II rests in the notch in the disc 89, the needle valve 14 is open.

To start the burner, the lever 12 may be manually held in the position shown in Fig. 2 with the valve 14 closed. This causes a rise of pressure within the air supply pipe through operation of the motor and compressor which is understood to be in operation at the time and the consequent deflection of the diaphragm 6| to the position shown in Fig. 2 opens the fuel valve. After the fire has been burning a short time the helix in the furnace radiator ring Ii, which has become heated, rotates the disc so that the lever upon release by the operator has the pin 'Il resting upon the periphery of the disc therebyholding the needle valve ll closed and the fuel for continued use of the furnace through consumption of fuel within the furnace itself, the valve 5 in the exhaust flue I is closed and a valve 11a in the fine 1 is closed. This permits the furnace to be operated in the usual way with the nre in the grate indicated by th dotted line It and the products of combustion will pass out through the usual exhaust conduit 3. Under this condition, the valve plate 5 prevents soot or dust from entering the oil burner chamber.

When used with the oil burner the valve I is open and the valve 11a is also open so that the products of combustion pass through the radiator ring 8 downward through the furnace and out through the flue I.

' The combustion chamber is formed ofiire resistant material'into which oil is discharged tangentially and to which air is progressively provided through apertures therein as the combustible products pass linearly through the chamber to finally discharge into the furnace. The invention is not confined to the use of a combustion chamber as shown in Figs. 1 and 2.

With a rotating body of the gases and air entering only from the exterior of the gaseous body, the central portion does not in some cases receive suflicient air for combustion or at least for complete combustion by the time the gases pass from the chamber and this, of course, varies with the diameter of the body of the rotating gases. By the arrangement shown, the gaseous body is provided with air in the interior as well as the exterior thereof.

By the construction of the combustion chamber hereinbefore described and particularly by the constructions shown more fully in Figs. 1 and 2, a complete burner outfit may be installed in conjunction with an ordinary wood or coal burning heating furnace without removal of any of the usual furnace parts leaving it all in normal state. The installation may be made at very valve open permitting the burner to continue in operation.

It is to be seen from the foregoing that there are preferably two instrumentalities for controlling the oil burner, one consisting of the thermostat structure 82 for varying the rate of consumption of oil to correspond with the temperature changes in the room being heated, and the other consisting of the safety control 88 both of which operate through a release of air pressure in the air supply connected to the nozzle or nozzles. The room thermostat structure 82 and capacity of the port controlled by the needle valve 64 is such as to reduce the pressure but not to such extent as to quickly or fully close the fuel valve and its operation is therefore to control the burner in the amount of fuel consumption while the structure indicated generally at 88 is adapted to cause complete cessation of the little cost, it being only necessary to provide the flue I open to the ash pit of the furnace and to the exhaust flue 3 of the furnace to which the discharge flue 2 of the combustion chamber is connected and also to provide a threaded opening in the radiator ring or correspondingly similar structure of the furnace for introduction of the safety trip 68.

The burner may thus be completely set up in all its relationship of parts even including the trip 86 at the factory and practically adjusted prior to installation and thus upon installation and connection of the thermostat B2 and air supply pipe therefor and the oil supply pipe the way that may be found desirable where a complete combustion of gases is desired. The burner may be used in the production of heat for .any purpose and, as before stated, the invention is not only in the construction of the combustion chamber and the associated fuel supply pipe etc., but exists fundamentally in the method by which the fuel is progressively burned in passing through the chamber. In so far as this feature is concerned, the fuel may be of various forms in which it is first brought to a temperature above combustion temperature and given a rotary motion and passes linearly or outwardly through the chamber during which air for combustion is added as the gases pass progressively through the chamber. The air may be introduced to the exterior of the rotating body only or to both the exterior and interior thereof and in the same direction II the body of gases is rotating to increase the rapidity of rotation.

By this method of burning a very quiet combustion is attained. This quietness is due firstly to the excess of fuel over air and next to the fact that the fuel jet is surrounded by combustion gases and gasified fuel which prevents contact of the free air with the jet and thirdly to the fact that the air is admitted in small streams to the gasifled and heated fuel that are distributed over a comparatively large area and therefore I do not secure a successive ignition within the mixture or a periodic portional heating of the mixture and thus avoid flame noises which are produced in other types of burners through the individual combustion of portions of the combustible mixture which reach ignition temperature at different time periods.

Thus while I have herein described a specific use of my improved combustion chamber, the invention is not confined to such use as the combustion chamber need not of necessity be positioned with its longitudinal axis in vertical position as is the desired arrangement in .the use of the burner illustrated.

From the foregoing description it is believed evident that the various objects of the invention are attained by the structures described, and that a comparatively simple and economic construction is secured.- I

Having thus described my invention, its utility and mode of operation, what I claim and desire to secure by Letters Patent of the United States is:

1. In an oil burner for use with a furnace having a combustion chamber, a nozzle for discharge of hydrocarbon fuel into the combustion chamber, a fuel line connected with the nozzle, a fuel valve for controlling the flow of liquid hydrocarbon through the fuel line, a compressor for providing air under pressure to the nozzle to cause the liquid fuel to discharge into the combustion chamber in atomized form, and a means for ignition of the fuel, means actuatable by temperature change to vary the position of the fuel valve from an open to a closed position comprising a thermostatic element, a conduit connected with the air line and having an opening to atmosphere, a valve actuatable by the thermostatic element to open or close the said conduit to thereby permit or prevent escape of air from the air line, a spring restrained pressure actuatable means open to the air line and through the air pressure openings the said valve in the fuel line, the opening or closing of the said valve in the conduit through operation of the thermostat providing a means for varying the air pressure applied to said pressure actuatable means to thereby vary the position of the fuel valve and means actuable by certain high furnace temperature to relieve the air pressure applied to said pressure actuatable means to thereby close the fuel valve.

2. In an oil burner for a furnace having a combustion chamber, a nozzle for discharge of hydrocarbon fuel thereto, a fuel line and an air line connected with the nozzle. means for causing a flow ofifuel through the fuel line and nozzle, means for providing air under pressure in the said air line to cause discharge of fuel in atomized form into the combustion chamber, and a valve in the fuel line for varying the volume of fuel discharged to the nozzle per unit of time, a control means for the said valve, comprising a chamber. a

a diaphragm forming a wall thereof, said air line having a connection with the said chamber I whereby the pressure of the air may move the diaphragm in one direction to open the valve, spring means associated with the valve and diaphragm for moving the valve in the opposite direction on reduction in pressure in the diaphragm chamber, a valve controlled discharge aperture through which air may pass from the air line, a valve for closing the aperture, and a temperature sensitive means for varying the position of the said last named valve to thereby vary the pressure in the air line and diaphragm chamber in accordance with temperature change, a second temperature sensitive means subject to the furnace temperature including a valve for opening the air line to atmosphere to thereby close the fuel valve on certain high furnace temperature.

3. In an oil burner having a combustion chamber, a nozzle for the discharge of liquid hydrocarbon fuel thereinto, a fuel line connected with the nozzle, a fuel valve for controlling the flow of liquid hydrocarbon through the fuel line, a compressor for providing air under pressure to the nozzle to cause the liquid fuel to discharge into the combustion chamber in atomized form, and a pilot light for ignition of the fuel, a control means for varying the volume of flow of fuel and of the air to the combustion chamber comprising a thermostatically controlled valve, a conduit connected with the air line and having an opening to atmosphere, a valve for controlling the said opening, an expandable element, the said air line being connected therewith whereby certain pressure of the air may expand the said element, said fuel valve being associated with the said expandable element and held in open position by the expansion thereof, a spring tending to close the valve, the thermostatically controlled valve upon opening of the air conduit releasing the pressure in the air line and the expandable member whereby the position of the fuel valve may be varied from the full open to the closed position in response to temperature changes affecting the thermostat, a safety device including a thermostatic element and a safety valve arranged to open or close the air line to atmosphere, the thermostatic element of the said control means being so arranged that, under the heat of combustion, the safety valve is held closed and upon practical cessation of combustion the safety valve is opened a to thereby release the pressure in the air line and expandable member and close the fuel valve.

PHILIP s. ARNOLD.

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