US1661794A - Oil burner - Google Patents

Description

Mai'ch 6; 1928.

O. A. FOGARTY OIL BURNER Filed Dec. 3. 1925 4 Sheets-Sheet 1 m v W ATTORNEY 4 Sheet s-Sheet 2 Rh Q ATTORNEY 0. A. FOGARTY OIL BURNER Filed D60. 23. 1925 March 6, 11928.

n a $1 Q March 6, 1928. 1,661,794

0. A. FOGARTY OIL BURNER Filed Dec. 23. 1925 4 Sheets-Sheet 4 any. .9.

Patented Mar. 6,

UNITED STATES onvnmn A. IOGARTY, or xomanan, Queue, can.

on. some.

Application filed December 23, 1925. Serial Io. 77,8.

My invention relates to oil burners and more particularly one of that type known as power burners, wherein the elements of a fuel mixture are delivered to a point of combustion by motor driven pumps as distinguished from gravity feed of the oil and intake of air through a furnace opening.

' Generically my improved burner comprises, in combination with a main fuel supply tank, a vacuum tank for local supply to the burner, a fan blower for delivering air through a conduit to the combustion chamber, a pump for drawing oil from the vac uum tank through a carburetor wherein the oil is atomized and mixed with a primary supply of air, and then delivering it from a discharge nozzle, a motor for driving the fan blower and oil pump, electrical ignition for the fuel mixture, and automatic controls for shutting off the motor in case of accident, faulty operation or overheating, and for regulation of vacuum and pressures of feed of the fuel elements.

Specific features of the'burner include a stabilizer for supply of oil to the nozzle, an oil vacuum and pressure regulator, an air vacuum and pressure regulator, and other major and minor details of construction to be hereinafter described.

The principal object of the invention is to provide a burner of this type, which is safe, eflicient and economical in o ration, easily installed. and of moderate rst cost.

In accomplishing'this and other objects of theinvention I have provided improved details of structure, the preferred forms of which are hereinafter described and illustrated in the accompanying drawings, wherein Fig. 1 is a side elevational view of a burner embodying my improvements, applied to an ordinary warm air furnace, the spout and oil pump being shown in section for better illustratlon.

Fig. 2 is a plan view ofthe burner, a part of the spout being broken away to better illustrate the ignition means.

Fig. 3 is a detail sectional view of the delivery end of the spout and'the oil nozzle, particularly illustrating discharge of air and oil to the combustion chamber.

Fig. 4 is a plan view of the delivery end of the spout and nozzle tip, the spout being partially broken away to illustrate the ti Fig. 5 is an enlarged, sectional, detail view of the nozzle tip.

. trating the relative Fig. 6 is a detail view of the spout illusareas of the inlet and the outlet.

Fig. 7 is a detail perspective view of the air vacuum and pressure regulator.

. Fig. 8 is a sectional view through the bacllpass oil vacuum and pressure regulator.

Fig. 9 is a detail sectional. view of the safety switch.

Fig. 10 is a detail, elevational view of the mercury switch, parts being shown in sec tion for better illustration.

Fig. 11 is a diagram of the" electrical control wirings.

Referring more in detail to the drawings:

1 designates a housing for mechanical parts of the burner, com rising a box of shectmetal or other suita le material, having a substantial base 2, provided with leg flanges 3 for supporting the housing at a suflicient hei ht from a floor to provide space for piping therebeneath, the walls of the housing being preferably securedto the base by screws-or bolts 4 so that the body of the housing may be removed to afford access to the mechanical arts. The end walls of the housing are pre erably provided near one vertical edge with brackets 5, in which legs .6 are adjustably fixed by set screws 7 to support one side of the housing and provide for leveling it on an uneven floor.

Supported on the base 2 is a motor 8, a fan blower housin 9 and a pump housing 10, all in train and preferabl in the order named. The motor may be of any ordina type and has a shaft 11 extending throng the fan blower and pump housings to drive the fan and pump direct, a flexible coupling 12, however, being interposed in it between the motor and fan.

The fan housing comprises a tangential neck 13 which extends through the rear wall of the main housing 1 and attached to said below the grates, after which the opemn is bricked up about the. spout as at: 17 an the pit lined with refractory material 18. The spout is preferably inclined downwardly from its outlet to the fan housin to drain any overflow from the nozzle be 1 from a carburetor 35.

into the housing and revent its accumulation in the bottom of t e furnace.

The delivery end of the spout is peculiarly constructed for the particular purpose hereinafter described, the top and bottom walls 19-20 being concaved on different radii but substantially equal to those of the ash pit, the top wall. on ashorter radius than the bottom wall but the out being deeper to form an outlet over the end of the bottom wall through which air may be relieved.

The delivery end of the spout is lined iiiside and out with a coating 14 of enamel or the like to prevent its disintegration under heat from the furnace. The front end of the spout is circular to fit the end of the neck of the fan housing but is of about 40% less cross sectional area than the elliptical discharge opening in order to reduce velocity and thereby avoid smothering at the outlet.

Fixed to the shaft 11 within the fan housing 9 is an ordinary blade fan 21 whereby air drawn in through an opening 22 in a side wall of the housing is delivered through the spout to the furnace.

Flow of air through the opening 22 is preferably regulated by a flap valve 23, pivotally mounted on a lug 24 on the fan housing and adapted for covering the opening 22, the flap having a central opening 25 through which the shaft 11 projects and through which a normal amount of air may pass to the fan.

Fixed to the flap valve above its pivotal mounting is an arm 26, which underlies an eccentric disk cam 27 on a shaft 28, journaled in brackets 29, on the base 2 and having a handle 30 accessible from the exterior of the housing 1 so that the flap valve may be adjusted toward or from the fan housing to regulate admission of a volume of air to the fan in addition to that passing through the normal opening.

The pump housing 10 is bolted or otherwise attached to the. outer face of the fan housing, eccentrically with relation to the shaft 11, and is provided with the peripheral intake and exhaust ports 31 and 32, the intake port 31 communicating through a tube 33 with an expansion chamber 34 leading The carburetor coinmunicates with the bottom of a vacuum tank 36 attached to the outside of the main housing through a pipe 37 and valve chest 38, the latter comprising a valve indicated by the chest 38 operable by the rod 28 from the handle 30 whereby the flap valve 23 is contracted, so that flow of oil to the carburetor may be regulated simultaneously with regulation of flow of air to the fan blower.

The vacuum tank is supplied from the main storage tank (not shown) through a pipe 41 leadinginto the top of the vacuum tank and air is exhausted from the top of the vacuum tank to create and maintain an operative vacuum therein, through a pipe 42 which leads from the top of the vacuum tank to the expansion chamber 34, so that when the pump is in operation, its suction will simultaneously draw vapor from the carburetor and maintain a vacuum in the tank 36.

Auxiliary air is supplied to the carburetor through a filter pipe 44, having intake openings 45 and a valve 46 whereby the volume of auxiliary air may be controlled.

The pump housing comprises a stator and fixed on the shaft 11, within the housing, is a cylindrical rotor 47, having snug end fit against the end walls of the housing and having diametrically opposite, radial grooves 48 extending throughout its length and slidably containing blades 49 of a width equal to the depth of the grooves so that when the blades are fully housed, their outer edges are circumferentially flush with the outer face of the rotor.

The eccentric arrangement of the shaft 11 and diameter of the rotor 47 are such that the rotor will contact the wall of the stator between the intake and outlet ports 31 and 32 and form a crescent-shaped annulus within the stator, the greater width of which is diametrically opposite the contact point. Consequently, when the pump is in operation, centrifugal force generated by travel of the rotor in an anti-clockwise direction will progressively extend the blades to contact with the stator, so that after a blade has passed the intake port, it will force fluid in advance of it toward and into the outlet and draw fluid from the intake into the space in its rear. With this arrangement, volume of the delivered fluid is determined by speed of the rotor and is in direct proportion to the volume of air supplied by the fan blower. In order, however, to provide for variations in richness of the fuel mixture, I have equipped the pump with a connection between the discharge portion 48 and intake portion 49 of the annulus comprising a pipe 50, carried by one of the end walls of the pump housing and leading from the discharge annulus chamber 48 at a point near the outlet port 32 to the intake chamber 49 at a point near the inlet port 31, and provided with a valve 50. \Vith this arrangement, part of each charge of fluid in the delivery chamber 48 may be backpassed into the intake chamber, relieving the discharge and reducing the proportion of o l to air in the fuel mixture. the proportions of oil to air and resultant richness of the mixture being regulated by the backpass valve.

Mounted in the outlet port 32 is a T coupling 51, and leading from one branch of the coupling is a pipe 52 which extendslltl eanne through an opening 53 into the fan housing neck and through the neck and spout to near the discharge end of the spout. Mounted on the end of the pipe 52 is a nozzle 54 comprising a base'member 55, having an car 56 through which a bolt 57 extends 'to attach the block to the bottomof the spout and anchor the pipe and nozzle in place.

Rising from the base is a delivery head 58 having a closed top and having a slit 59 in its front face upwardly inclined to deliver vapor through the mouth of the spout at an angle substantially intersecting a plane perpendicular to the ends of the side walls of the spout.

Vith' the described arrangement of the spout and nozzle outlets, air from the fan blower is delivered past the nozzle, both above and below the stream of atomized oil, the air above the oil spreading the latter in a flat stream tov facilitate its mixture with the combustion supporting air rising through it from beneath and mufile sound of combustion of the mixture.

The oil conduit 52'is preferably inclined upwardly from the-fitting 51 to a peak 60 and from the peak 60 and nozzle 54 downwardly toa trap 61, so that oil remaining in the pipe after the motor has stopped will drain to the pump and trap and avoid overflow onto the furnace floor.

In order to provide a constant pressure flow of oil to the nozzle, I mount a-dome 62 on the upper branch of the T fitting 51 wherein a supply of fuel is maintained by the pump against air pressure to compensate for intermittent reductions in pressure in the pump.

Ignition of the fuel is effected by electrodes 6-165 extending past the nozzle at converging angles and gapped in front of the nozzle and below the line of flow of the oil stream so that sparks at the gap will ignite the rich mixture as it leaves the noz zle and joins the combustion supporting air;

the electrodes being carried by plugs 6667 which extend forwardl through openings 6869 in the sides of t e spout and are removably mounted in housings 707 1, having base lates secured to the spout and covering sai openings.

Referring now to the circuits for supply ing current to the motor and electrodes, 7 3 74 designate positive and negative lead wires of an ordinary house lighting circuit controlled from a master switch 75, and 7677 conductors from the leads to the motor, the conductor 77 including a manually operable switch 78, enclosed within a housing 79 having a base plate 80 attached to the front wall of the main housing 1, and whereby the motor may be. started or stopped at will by means of a push button 81 operable on the switch lever 82, pivoted in a bracket 83 on a non-conductive plate 84 fixed within the housing 80 and normally, yieldingly held out of engagement with a contact clip 85 b a spring 86 connected with the arm 87 o lever 82 and with a hook 88 on the plate 84.

The conductor 76 includes an ordinary type of thermostatic switch 89 for making and breaking the circuit under varying temperatures in a room served by the burner, to start the motor when temperature in the room falls to a given degree and stop the motor when the temperature exceeds another given degree.

The electrodes are served from a trans former 90 in a branch 91 of the conductor 77, through conductors 92-93, vibrating coils 9-.l-95 and wires 96-97 leading from the coils to binding posts 9899 on the respective plugs.

To safeguard against continued operation 35 of the motor and flooding of the burner in case'of failure of the ignition, I locate a cut-out in the ignition circuit consisting of a thermostat 100 which is located in an extension-101 of the switch housing 79 and projected through an opening in the main housing wall to the interior of the main housing, one end of the thermostat being adjustably anchored to the head 102 of the extension 101 by a screw 102': the other end of the thermostat carrying a bar 103 which extendsforwardly through an opening 104 in the back of the switch housing 79 and is slidably mounted in a collar 105 in the plate 84, the forward end of the bar having a slot 106 through which the switch blade 82 projccts, so that when heat generated within the housing extension expands the thermostat, it will push the'bar 103 out against the tension of a spring 107 that surrounds the bar and bears against the collar 105 and tion conductors 9293, the lead 109 including a mercury switch 110 for making and breaking the circuit through the thermoftat.

The mercury switch comprises a U-shaped tube 111, contained within a housing 112 and attached in place by a clip 113; The

upper ends of the legs 114-115 of the tube are closed by caps or plugs 116117 and extending through the caps or plugs are the ends 118119 of the respective sections of the conductor 109'. which terminate in spaced relation at the bottom of the tube within the mercury pool 120, which, normally forms a conductor between the terminals.

Opening to the leg 114 of the mercury tube is an air conduit 121. whichle'ads through the spout to the nozzle 54 and there terminates in a. loop 122 which embraces the nozzle so that when the burner is in operation, heat from the combustion will expand the air in the conduit and push the mercury out of the leg 114 into the leg 115 of the tube 111 and break the circuit between the terminals 118-119.

With this arrangement when the burner is started in operation and the fuel properly ignited, heat from the combustion expands the air in tube 119, causing it to force the mercury from leg 114 into leg 115 of the mercury tube and breaking the connection between the terminals. lVith its circuit broken, the thermostat will not heat and the switch lever 82 will be undisturbed. However, should the electrodes fail to spark and ignite the fuel, there will be no expansion of the air in tube 121, the circuit through the thermostat coil will remain closed, and heat from the coil will expand the thermostat to extend the bar 103 and cause it to push the switch lever 82 out of engagement with the contact clip 85, thereby breaking the circuit through the motor and rendering the burner inoperative, until the trouble in the ignition is corrected.

Should the flame from the burner become extinguished either through lack of oil or any other cause, thefurnace will cool down, cooling the conduit 119 and permitting the air therein to contract, which permits the mercury to rise in the leg 114.- of the mercury tube and make contact with the terminal 120 to bring the heating coil 107 again into circuit, heating the thermostat 100 and causing it to expand, pushing the bar 105 against the switch lever 82 to remove it from the contact clip 85, breaking the circuit to the motor and stopping operation of the burner.

Should the operator push the lever 82 into contact with the clip before the thermostat has cooled off or before the burner has been repaired or the oil replenished, the thermostat will again push the lever from the clip. Should the thermostat become inoperative due to the leakage of expansible material, the spring 107 will further compress the thermostat and cause the bar 103 to pull the switch lever toward the panel 84 and disconnect it from the clip. The operator cannot then close the switch with button 81 until the damaged thermostat has been repaired or replaced.

Assuming the parts to be constructed and assembled as described, the operation is as follows:

Manipulation of the button 81 closes the motor circuit through switch 78 and the motor operates the fan blower and oil pump. Suction in the pump draws oil from the vacuum tank into the carburetor where it is atomized and mixed with a preliminary supply of air to form a rich fuel mixture,

which is delivered from the pump under pressure to the nozzle at the outlet end of the spout, where it is ignited by the electrodes which have been energized upon the closing of the motor circuit. The fan blower delivers air under pressure through the spout and past the nozzle, the particular construction of the outlet end of the spout permitting the stream of air to escape rearwardly and upwardly within the furnace and the inclined slot in the oil nozzle discharging a stream of air into and along the line of flow of the air stream; the upper volume of air keeping the oil stream flat and deadening the sound of comluistion, the lower volume of air passing up through the oil stream to combine therewith and support the combustion. The fan blower and pump are initially adjusted to provide a suitable fuel mixture but should a leaner mixture be desired. the proportion of oil to air may be reduced by opening the valve in the back-pass from the discharge to the intake sides of the pump, it being apparent that any desired proportion may be secured by manipulation of the back-pass valve.

If the fuel mixture ignites properly, heat of combustion warms the loop on the end of the tube leading to the mercury switch, expanding the air within the tube and generating the pressure which forces the mercury from one leg of the switch into the other, breaking the connection between the terminals controlling the coil of the thermostat 100 so that the thermostat remains inactive and the motor circuit is maintained until opened manually by the button 81 or by the thermostat 89 which is controlled by temperature within a room served by the burner.

If the electrodes are not energized to produce a spark or should there be a stoppage in the oil flow line so that no combustion is produced, then air in the switch tube is not heated, no pressure is generated in the inercury switch and the circuit through the thermostat coil remains closed and the coil is heated to expand the switch bar and open the switch, thereby cutting off the motor and indicating that repairs are necessary. Subsequent manipulation of the starting button will have no effect as pressure on the button will merely close the switch lever against the tension of the spring in the thermostat, which will again open the switch as soon as the pressure is relieved.

Should the thermostat fail to operate under influence of its coil because of interference in case the bellows of the thermostat becomes inactive due to the leaking out of the expanding medium, the spring 107 will compress the bellows and force the bar 103 rearwardly to pull the switch out of engagement with its contact clip, thereby cutting out the motor and discontinuing operation of the blower and oil pump and the burner cannot be started again until the defective bellows has been replaced.

It is apparent, therefore, that with the construction and arrangement of parts heretofore described, I have not only provided for eflicient delivery of the fuel elements to the combustion zone but have safeguarded against fire hazards due to flooding in case of accidental discontinuance of ignition or interrupted flow of fuel, have stabilized the oil delivery, have provided asimple and elficient means for varying the richness of the mixture, and have accomplished other results desirable in a burner of this type. What I claim and desire to secure by Let-,

tiers-Patent is:

1. In an oil burner, a spout having its upper wall back-cut from its lower wall at the outlet end, a nozzle located at the outlet end of the spout and having a forwardly and upwardly directed slot, means for delivering an oil stream from the nozzle slot, and means for delivering air above and below the oil stream.

2. In an oil burner, a spout comprising a transversely flattened outlet end having its top wall back-cut from its bottom wall, means for delivering air under pressure through the spout outlet, and a nozzle located in the spout adjacent the outlet, having a slot inclined to discharge an oil stream into the air stream and along the line of flowthereof.

3. In an oil burner, a spout having a flattened delivery end formlng a transversely elongated outlet, the top wall being backcut from the bottom wall to form an outwardly and upwardly opening dischar mouth, a nozzle seated on the bottom of t e spout near the discharge mouth, and having an inclined slot for discharging a stream of oil outwardly and upwardly in a flat stream through said discharge mouth, means for delivering il under pressure from the nozzle, and. means for delivering air from the spout under pressure and 1n streams above and below the oil stream.

In testimony whereof I aflix my ature;

ORVILLE A. FOG TY.

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