US2451964A - Multiple nozzle gun type oil burner and control therefor - Google Patents

Description

Oct. 19, 1948. J. A. LOGAN 2,451,964

MULTIPLE NOZZLE GUN TYPE OIL BURNER AND CONTROL THEREFOR Filed March a, 1947 4 Sheets-Sheet 1 INVENTOR 'Joazw/ A. [OM/Y (Lia aw 1 A TTO EYS Oct. 19, 1948. J. A. LOGAN MULTIPLE NOZZLE GUN TYPE OIL BURNER AND CONTROL THEREFOR 4 Sheets-Sheet 2 Filed March 3, 1947 INVENTOR Joa'P/IA. lac-An! ATTO N EYS Filed Mafch s, 1947 4 Sheets-Sheet 3 t 6 w m U mm Z E R wm W m H A n P a a 06L 1948- J. A. LOGAN 2,451,964

MULTIPLE NOZZLE GUN TYPE OIL BURNER AND CONTROL THEREFOR Filed March a, 1947 4 Sheets-Sheet 4 1 I INVENTQR DJ BY 46 {2 ,40} 9 116 63 Q 69 ATTOR EYS atcnte 9, 1948 MULTIPLE NOZZLE GUN TYPE OIL BURNER AND CONTROL THEREFOR Joseph A. Logan, Hadley, Mass., asslgnor to Gilbert & Barker Manufacturing Company, West Springfield, Mass, a corporation of Massachusetts Application March a, 1947, Serial No. 731,919 Claims. (Cl. 158-28) This invention relates to improvements in oil burners of the so-called gun type for house heating systems.

From the manufacturers standpoint the success of his equipment in use depends to a large extentupon the skill used in installing the oil burner in the home. The installing work is customarily done by men employed by the distributors who buy from the manufacturers. Of course the. manufacturers supply literature and offer training to guide the men in the field to install oil burners to the home user's advantage. Yet there are some features of the gun type burner which under to-days routine practice cause them to operate less efiiciently in the home than they can be made to operate under this invention. The object of the invention is to provide a new and improved burner of the said type, feasible to be made at the factory, distributed for installation under to-days routine practice, and result in the user getting a burner in the home to operate with a substantial increase of efilciency as compared to prior art burners. By efilciency is meant particularly the efficiency in the burning of the oil with resulting economy in oil consumption. In some installations the invention will avoid disagreeable noise in burner operation as compared to prior art burners under the same conditions.

The structure and mode of operation of the invention is disclosed by way of example and in detail. Considerable discussion is needed to show the reason for much of the detail.

For the house heating use, it is necessary to vary the firing rate of the burner over a certain range, say from a minimum of one gallon per hour to a maximum of two and three quarters gallons per hour. The firing rate is determined by the size of atomizing nozzle used. The size of the nozzle tobe used is determined bythe dealer who installs the burner. The manufacturer desires to standardize on one size of burner which by merely change of nozzle size will be adequate for any firin rate within the stated range. However, as the firing rate is varied of course the rate of oil flow is varied and the rate of air fiow through the air tube of the burner needs to be correspondingly varied. Using one air tube of a given size, the change of rate of air flow will result in a change in the velocity of the air supplied through the .tube to the oil atomizing nozzle. Over the desired range of firing rates, the variation in air velocity is so great as to result in inefiicient mixing of air and oil at certain firing rates. For example, if the air tube is proportioned to provide the proper velocity of air for eflicient mixing at a high firing rate, then, when air is passed through the same size tube at a substantially less rate for low rate firing, the velocity of the air will be lowered to such an extent that there will be a substantial loss in the efllciency of 2 the mixing of the air and oil. However, if the air tube is proportioned to provide the'proper velocity of air for efilcient mixing at a low firing rate, then, when air is passed through this same tube at a substantially greater rate for high rate firing, the velocity of the air will be so high as to cause objectionably noisy combustion and possibly also to change the desired shape of the fiame.

This invention has for an object to provide in a burner of the described type for house heatin purposes, a plurality of air tubes of different diameters, arranged one within another, and valve means to enable the air for combustion to be supplied through one or more of these tubes, according to the oil firing rate selected for the burner.

The invention finds one preferred use in connection with a burner of the type described, which is adapted to be fired at more than one rate according to the user's choice or as determined automatically by a suitable control, and the invention has for a further object to provide means, whereby a change in the oil firing rate will automatically cause a change in the number of air tubes used to supply the air for combustion. In this way, for two rates of oil firing, two air supply tubes may be provided suitably proportioned so as to yield approximately the same velocity of air for high rate and low rate firing.

In the accompanying drawings:

Fig. 1 is a side elevational view of an oil burner embodying the invention;

Fig. 2 is a. cross sectional view thereof taken on the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary top plan view, with parts broken away to show the air inlet valve together with the manual means and the automatic means for moving it Fig. 4 is a sectional plan view taken on the line 4-4 of Fig, 1 and showing the dual air tube structure and the valve control therefor;

Figs. 5 and 6 are cross sectional views taken on the lines 5-! and 6-6, respectively, of Fig. 4;

Fig. 7 is a fragmentary sectional elevational view taken on the line 1-! of Fig. 2;

Fig. 8 is a sectional plan view taken on the line 8-8 of Fig. 6, showing the firing rate selector valve;

Fig. 9 is a fragmentary sectional view of a detail relating to the mounting of the air inlet valve;

Fig. 10 is a wiring diagram of the electrical elements and circuits of the burner;

Fig. 11 is a fragmentary sectional plan view showing a modification; and

Fig. 12 is a diagram illustrative of a modification in the control shown in Fig. 10.

Referring to these drawings, the invention will be disclosed in what is now considered its best form, in which the spray producing means is a nozzle of the oil pressure atomizing type. However, the ihve'ntion is capable cf use with' other types of atomizing nozzles, as will be clear to those skilled in the art, and it is not intended to have the invention limited to the use if the one specific type of atomizing means shown in the drawings.

Referring first to Fig. 1. the frame of the burner includes a hollow casting, which may be supported by a pedestall and which has a lower cylindrical part 2 and an upper part 3, forming a housing for a fan shown in part at 4 in Fig. 3. This fan delivers air at relatively low pressure, say a few ounces, into the rear. end of the tubular passage 8 (Figs. 1 and '7), which extends through part 2 and is closed at its rear end by a cover 8. On one face of the fan housing 3 (Fig. 3) is mounted an electric motor 1, which drives the fan 4 and an oil pump 8. The pump is fixed centrally to the cross bar portion 3 of a U-shaped frame, the spaced legs I!) of which are fixed at their inner ends to the other face of fan housing 3. A casing Ii encloses the frame 8, l3 and part of pump 8 and has a plurality of air inlet openings l2. Air passes through these'openings into the hollow interior of casing ii and enters the fan housing 3 through the inlet opening I3. An adiustable shutter I4 controls this opening. The fan 4 is fixed directly to the shaft l5 of motor 1.

The pump shaft i8 is preferably. driven from the motor shaft by means of a centrifugal clutch, the driving and driven elements of which are respectively indicated at l1 and- I8. This clutch may be like that disclosed in my c'opending application Serial No. 672,106, filed May 24, 1946, and its purpose is to delay the starting of the pump until the fan has acquired considerable speed and to stop the pump before the fan. The pump may, for example, be constructed as shown in the patem; to Osborne No. 2,233,709, dated March 4, 1941, and include a cut-off valve andby-pass valve located in the casing i9. The pump is arranged to draw in oil through a suction pipe 20 (Fig. 1) and 'force it out through a delivery pipe 2| to the burner. The cut-off valve in the casing |8 will open to allow flow from the pump to pipe 2| only after a predetermined minimum pressure, say 85 pounds per square inch, has been established. The by-pass valve opens to allow oil to by-pass to the suction side of the pump, when. the pressure of the pumped oil reaches a predetermined maximum pressure, say 100 pounds per square inch.

Referring to Fig. 4, the tubular air passage 5, into the rear end of which air is delivered by fan 4, communicates with two coaxially arranged tubes 22 and 23. The outer tube 22 has a flanged end 24 which is fixed as indicated to the outlet end ofthe cylindrical member 2. The inner tube 23 is supported from the outer tube by two circ'ular series of radial posts 25, each of which is riveted to both air tubes. The outer and inner tubes 22 and 23 are provided on their outlet ends with air directing cones 28 and 21, respectively.

Within the inner tube 23 are arranged the oil atomizing means of the burner. In the particular example herein shown, such means consist of two nozzles 28 andv 29 (Figs. 2 and 4) of the oil pressure atomizing type. These nozzles 28 and 29 have different capacities and may, for illustration, be

assumed to have the respective capacities of one and two gallons per hour. These nozzles 28 and 29 (Fig. 4) are mounted on the outer ends of pipes 30 and 3| respectively, which are mounted in spaced parallel relation and are secured at their inner ends to a casing 32, which contains a firing rate selector valve. The oil delivery pipe 2| from the pump 8 extends through a recess in cover 6 into passage 5 and is connected to the valve casing 32 as shown.

The firing rate selector valve is best shown in Fig. 8. The oil supply pipe 2| communicates with one end or an inlet passage 33 formed in casing slidably mounted in cylinder 34. The stem 33 passes out of casing 32 through a suitable packing 40 and a packing nut 4| and is provided with a spring 42, which presses against a collar 43 on the stem and yieldingly holds it in the low firing rate position shown. In this position, the valve disc 38 blocks oi the high rate outlet 38 and the valve disc 31 uncovers the low rate outlet 38 and enables it to communicate with inlet 33. If the valve is moved to its high firing rate position, valve disc 31 will block off outlet 35 and valve disc 38 will open outlet 38 and allow it to communicate with inlet 33. A longitudinal passage 44, which extends from the outer face of one valve disc to the outer face of the other, enables oil to flow hack and forth from one end of the cylinder 34 to the other and thus permits ireedmovement of the valve.

The valve 31, 38 may be moved to its high firing rate positionby means of a lever pivotally mounted at 48 between ears 41 on the casing 32. One arm of lever 45 has a lateral extension 43 (see also Fig. 7) which underlies the collar 43 and is operable, when actuated by means later to be described, to raise the collar and thus the valve 31, 38. A light spring 48 connects the lever 45 to one of the ears 4'! and yieldingly holds extension 48 40 in contact with the collar 43.

The inner air tube 23 (Fig. 4) is proportioned to pass air at a rate and velocity suitable for operation of the burner at the lower firing rate. When the burner is operated at the higher firing rate, air is supplied at an increasedrate and then both air tubes 22 and 23 are used, the two enabling air to pass at the increased rate without substantially increasing the velocity. It is therefore necessary to provide means for closing and opening the entrance to the annular passage 83 between the inner and outer air tubes. Such means, as shown, consists of an annular ring 5|, to opposite faces of which are fixed stampings 52 of triangular shape in cross section. Th ring 5| has a diametrical part 83 (Figs. 5 and 7) to which are fastened at their inner ends two studs 54, arranged in spaced parallel relation (Fig. 7).

These studs are slidably mounted in bearings 88,

rovided on the valve casing 32, one above and one below the latter, as shown in Figs. 6 and 'l. The rear ends of the studs 54 are fixed to a cross bar 58. Springs 51, one encompassing each stud 54, are located between the part. 53 and the inner ends of bearings 55 and yieldingly hold the air valve in the closed position shown. Centrally on the cross bar 56 (Figs. 4 and 8) are a pair of spaced ears 58 which receive between them the outer end of the long arm of a bell crank lever 59 (Fig. 8) and to which such arm is pivotally connected by a pin 88. Bell crank 58 is mounted between the described ears 41 ajacent lever 48 and is pivotally connected to such ears by the same pin 48. To the short arm of bell crank lever 58 (Fig. 4) is connected a link 6| which extends outside the cylinder 2 and is connected to the lowthrough the casing II and is fixed to one of the arms I8. Fixed to the fan housing 3, as by legs 84 (Fig. 2), is a casing 85, which contains a solenoid. The core 88 of this solenoid is connected to lever 82. When the solenoid is energized by means to be described, lever 62 will be swung counterclockwise, as viewed in Fig. 2, thus pulling link 8| outwardly and swinging lever 59 clockwise, as viewed in Figs. 4 and 8. This will pull outwardly on the studs 54 compressing springs 51 and moving the air valve 5|, 52 to its open position. In such position the parts 52 of the valve serve as streamlining to guide th air around the air valve without creating undue eddies.

The described lever 45 of the firing rate selector valve is actuated by the bell crank 59 after the latter has opened the air valv to a substantial extent. A projection 6'! (Fig. 8) on the bell crank engages an abutment 88 on lever 45 and moves the latter to shift the firing rate selector valve to its high rate position. Thus, the annular air space 58 between air tubes 22 and 23 is opened whenever the selector valve is shifted to cause operation of the burner at the high firing rate.

The ignition means for the burner may include the spark electrodes 59 (Fig. 4) which are supported in proper position to ignite the spray from either nozzle 28 or 29. These electrodes are fixed one in each of two insulating tubes I8, which in turn are mounted for longitudinal adjustment in a support II, being suitably held in adjusted position as by the set screws I2. This support II also receives the low and high rate nozzle supply pipes 38 and SI respectively, which pipes are suitably held to the support, as by the set screws 13 (Fig. 2) in a manner to enable longitudinal adjustment of the pipes and thus the atomizing nozzles which they carry. The support has three radially extending ins 14 (Fig. 2) the outer ends of which contact the inner peripheral wall of the inner tube 23- and centralize the support. The selector valve casing 32 also has legs I5 (Fig. 6) which support it from the cylindrical member 2. The nozzles and spark electrodes may be held in proper longitudinal position in the air tube 23 in any suitable way. For example, two rods 18 (Fig. '7) are secured at one end one to each of two ears TI on the valve casing 32 and the other ends I8 of the rods are out turned at right angles, as at I8, and received one in each of two diametrically opposed notches formed in the rear end face of cylinder 2. The cover 8 holds the ends 18 tightly in their notches. The inner ends of these rods are threaded and secured to the casing by a pair nuts I5, in such a way as to enable longitudinal adjustment of the casing 32 and thus of the nozzles 28 and 29 and the electrodes 69. When the cover 8 is removed, one may reach into the tube and disconnect the link 8i from hell crank 59, after which the unit comprising firing rate selector valve, air valve, nozzles and ignition electrodes may be withdrawn from the rear end of cylinder 2 by pulling rearwardly on rods I5.

It has been stated that, when the firing rate selector valve is moved to its high rate position, air is supplied to the burner at an increased rate. This is accomplished by opening the shutter I4 to increase the eifective area of the air inlet to fan- 4. This shutter is threaded on a screw 88 (Fig. 3) and it is suitably held against rotation, as by a stud 88', fixed on cross bar 9. The shutter has a central opening large enough to clear the driven element I8 of the centrifugal clutch. The

screw 88 has an outer plain cylindrical portion,

which is mounted to slide axially as well as turn in a bearing 8I in the cross bar 8 and an inner plain cylindrical portion which is also mounted to slide axially as well as turn in a bearing 82 (Fig. 9) in the fan housing 3. A spring 83 (Fig. 3) on the screw tends to hold it in the axial position shown, in which a shoulder 84 on the screw abuts the cross bar 9. Threaded 'on this screw, near its outer end, is an adjustable abutment, such as a nut 85, and a lock nut 86 for holding the abutment in adjusted position. On the end wall of easing II (Figs. 1 and 2), a lever 81 is pivoted at 88 and has one end forked to straddle screw 88 in back of nut 85. The other end of lever 81 is connected by a link 89 to the upper end of the described solenoid-actuated lever 82. When the solenoid is energized, the lever 52 will be swung counterclockwise, as viewed in Fig. 2, thus pull ing on link 89 to cause lever 81 to swing clockwise, as viewed in Fig. 3, to engage nut and move screw 88 axially outward and move the shutter energization of solenoid, depends on the position of nut 85. The amount of movement of lever 81 is always the same but the axial movement imparted to screw 88 can be varied by varying the amount of lost motion between the lever and nut 85. The high rate position of the air shutter may be adjusted with precision by turning nut 85 on screw 88. The low rate position of the shutter may be adjusted with precision by turning the screw 88 which will move the shutter axially in or out as required.

The burner is arranged for intermittent operation under the control of a room thermostat switch. The electrical connections are shown conventionally in Fig. 10. The room thermostat switch 98 is arranged to close on a demand for heat from the burner and close a low voltage circult, which is supplied from the secondary M of a transformer and which includes a relay coil 92, the thermostat switch 98, the secondary 9I, and the wires 93, 94 and 95 that connect these elements in series. The primary 96 of this transformer is connected by wires 91 and 98 to supply wires 99 and I88, respectively. The relay coil 92, whenenergized, operates a switch IN to close a circuit to the burner motor and to the ignition means. The motor circuit may be traced as follows, from supply wire 99, wire I82, switch I8I,

' wires I83 and I88, motor I, and wire I85 to supply wire I88. The ignition electrodes 69 are connected by two wires I88 to the secondary I81 of a suitable ignition transformer, the primary I88 of which is respectively connected by wires I89 and M8 to the wires I84 and I85 and thus in parallel with the motor so as to be energized and deenergized simultaneously therewith.

The solenoid which serves to shift the lever 52 to adapt the burner for operation at the high firing rate is shown at III. It may be controlled automatically or manually as desired. As illustrative of the automatic control, a thermostat switch I I2 is arranged in a circuit, which includes in series the solenoid III and relay switch I8I, this circuit being traced as follows, from supply wire 99, wire I82, switch I8I, wires I83 and H3, thermostat switch II2, wire H4, solenoid III, and wire H5 back to supply wire I88. The therrate of air flow to be increased and the air valve 52 to be opened to enable both air tubes to conduct air to the oilatomizing means. For manual operation. a push button switch Ill (Fig. 12) may be substituted tor the thermostat switch H2 and connected to the wires 3 and III, respectively, so as to open and close the circuit to the solenoid I I I in the same way that it was done by switch II2. This switch II may be located at any convenient point in one of the living rooms of the house and it will then enable the burner to be changed over for high rate firing without going into the cellar to reach the burner. It is, however, obvious that the change over for high rate firing may be'efiected by means of a hand lever (not shown) located at the burner.

In operation, the burner is started up automatically by the room thermostat 80 when there is a demand for heat. Oil will be supplied by pump 5 to nozzle 28 or 29 depending on whether the firing rate control switch H2 or 5, as the case may be, is open or closed. If this control switch is open, the burner will be operated at the low rate while if it is closed, the burner will operate at the high rate. Air will be supplied by fan 4 at a high or low rate according to whether the selector valve is set for high or low rate firing. If air is supplied at the high rate, the air valve 5|, 52 will be opened by lever 59 when the selector valve and air shutter I4 are moved to high rate position. Then the two tubes 22 and 23 will be used to conduct air to the spray nozzle. If air is supplied at a low rate, the air valve 5|, 52 will be closed by lever 59 when the selector valve and air shutter are moved to low rate position. Then, the inner tube 23 only will be used to conduct air to the burner. The air tube arrangement aiiords two air conduits of diflerent cross sectional area, which can be proportioned so as to give the proper velocity of air at the atomizing nozzle for high and for low rate firing. As shown, one such conduit comprises the inner tube 22 alone and is used for low rate firing and the other conduit comprises both tubes and they are used for high rate firing. The air supplied from each tube will mix with the spray emitted from the nozzle 28 or 29, as the case may be, and the combustible mixture will be ignited by the electrodes 69 in the usual way. The burner will continue in operation until the demand for heat is satisfied, when the burner will be stopped by the opening of switch IOI, when the room thermostat switch 90 opens. On stopping of the burner, solenoid III will be deenergized and the air valve 52, 53, the firing rate selector valve and air shutter It will be shifted back to low fire position. It is obvious, however, that these various valves need not necessarily be shifted back to low fire position when the burner stops. They might, for example, be operated manually and latched in the high rate position in the same general way as is shown in Fig. 11, hereinafter described.

The invention provides for an automatic change in the cross sectional area of the air supply conduit as the rate of oil supply is changed,

whereby the velocity of air at the nozzle may be maintained about the same for both high and low rate firing. The arrangement enables one burner to serve eiiiciently for all usual firing rates throughout the range normally used for house heating systems. the manufacturer would have to supply burners with air tubes of different sizes, one for the relatively high firing ranges and another for the relatively low firing ranges. I! a single air tube were used of the proper size to give the desired air velocity for efilcient mixing of air and oil at high firing ranges, the same tube, when supplied with air at a less rate for low rate firing, would cause a decrease in air velocity so great as to result in inefllcient mixing or the air and oil and poor combustion. It a single tube were used properly proportioned to give the desired,air velocity for efiicient mixing for low rate firing, then when the same tube is supplied with air at the greater rate needed for high rate firing the velocity of the air would be so much increased as to result in too noisy combustion and probably also in substantial change 01' shape of the flame. With the invention, the air velocity may be maintained within a range to secure eflicient mixing for both low and high rate firing and to avoid noisy combustion.-

The invention is characterized in providing for the change in area of the air conduits as the oil firing rate is changed and, in its broader aspects, is not limited to the one means herein disclosed for varying the oil firing rate. The invention is useful regardless of how the change in oil firing rate is eflected.

The invention is also useful in all burners, wherein the change in firing rate has to be effected manually by changing the size of the atomizing nozzle used. This is indicated in Fig. 11, wherein a single oil atomizing nozzle I I9 and the ignition electrodes 59 are mounted in a support I20 in the inner air tube 23. This nozzle is supplied with oil through pipe 2| under pressure regulated by the usual cut-ofl and by-pass valves but without any other valve control. mounted on studs 54 as before and these studs are slidably mounted in a support I2 I in the same way that they were formerly mounted in the valve casing 32. Each of the supports I20 and I2I has supporting legs as before and the two supports are tied together by rods I22. Rods It are fixed at one end to the support I2I and at the other end fit in recesses in the cylinder 2 as heretofore. The support I2I pivotally supports the lever 59 which actuates the cross bar 56 to which are fixed the studs 54 of the air valve 5 I, 52. This lever may be manually operated fromoutside the cylinder 2 by pulling or pushing on a link I23. This link has a downturned end I which can be inserted in either of two holes I25 and I26 in an ear I21 on cylinder 2. When the end I24 is engaged in hole I25 the air valve 5|, 52 will be closed for low rate firing and when such end is engaged in hole I25 the air valve will be opened for high rate firing. The burner manufacturer might supply two air tubes with each burner, one tube to be used when nozzles of relatively low firing rates are used and the other tube to be used when nozzles oi relatively high firing rates are to be used. Such a-plan leaves the installation of the tube and that of the oil nozzle and ignition electrodes .to the dealer and the manufacturer has no assurance that the Installation of these parts will be properly eflected. The invention enables both tubes and all the parts supported in them, except possibly for the nozzles Except for the invention,

The air valve 5|, 52 is both of the tubes to be supplied with air by the fan.

From the foregoing disclosure it will now be clear that I have provided an improved oil burner for these advantages among others. When the workman installs the improved burner for house heating, the householder will get a burner better adapted for-that particular operation which will be eflicient in relation to his particular househeating needs. The burner structure is better adapted for the installing workman to condition it for emcient operation under the particular conditions of the house in which it is put for use. Whereas working with prior art burners different firing rates were determined by diiferent sized nozzles accompanied by different adjustments of air volume through the same air tube, the improved burner takes into account the increase in efliciency of difierent sized tubes in relation to the operation of different sized nozzles. The structure is arranged at the factory for the most convenient kind of installation work by men in the field with the result that less skill is needed in'doing the installing work of putting the mass produced burner into that kind of operation which is hi hly efilcient for one particular house as com ared to diiferent houses and within a substantial range. This is one of the broader aspects of the invention which is pointed out in various aspects by the following claims.

I claim:

1. In an oil burner for house heating systems, a 2

motor, an air fan, an oil pump. a transmission for driving the fan and pump from said motor. two air tubes arranged one within the other with a passage between them, the inner tube being permanently connected to receive air from said fan, valve means operable to connect or di connect said passage to or from the fan, oil atomizing means connected to be sup lied from said pump at either a high or a low firing rate and located in the inner tube in a position such that the air from the inner tube and the air from the passage between the tubes will mix with the spray emitted from the atomizing means, means for changing the firing rate of the atomizing means from a hgh to low rate and vice versa, and means operable with the rate changing means for actuating said valve means to open and close the passage between said tubes when the atomizing means is adapted for hi h and low rate firing res ectively.

2. In an oil burner for house heating systems. a motor, an air fan, an oil pump, a transmission for driving the fan and pump from the motor, two air tubes one within the other with a passage between them and connectedto receive air from the fan, oil atomizing means connected to be supplied by said pump and operable at either a high or a low rate. said means being located in the inner tube in a Position such that air from the inner tube and the air from the passage between the tubes will mix withthe spray emitted from said means, means operable to adapt said atomizing means for high or low rate firing, and valve means operable to permit air from the fan to flow either through the inner tube or through the inner tube and the passage between the tubes to adapt the air supply to the selected rate 01' oil supply.

3. In an oil burner for house heating systems. a motor, on air tan, an oil pump, a transmission for driving the fan and pump from the motor, two air tubes one within the other with a passage between them and connected to receive air irom the fan, two oil conduits selectively connectible to said pump and each arranged to end with an individual atomizing nozzle located in the inner tube in such position that air from the inner tube and the air from the passage between the tubes will mix with the spray emitted from either nozzle, valve means controlling the selective connection of said oil conduits to the pump to vary the firing rate of the burner, and a second valve means operatively connected to the first valve means and operable to permit air to flow through the inner tube or the inner tube and the passage between the tubes according to the selected firing rate.

4. In an oil burner for house heating systems, a motor, an air fan, an oil pump, a transmission for driving the fan and pump from said motor, twooil conduits selectively connectible to said pump and each arranged to end with an individual atomizing nozzle, valve means to control the connection of said 011 conduits to said pump to provide for a high and a low firing rate, and two air tubes arrangedone within the other with a passage between them, the inner tube being permanently open and both connected to receive air from said fan, said nozzles being located in the inner air tube in such position that the air from the innertube and the air from the passage between the tubes will mix with the spray emitted irom'either nozzle, and a second valve means operatively connected to the first-named valve means and operable when the first-named valve means is moved into position for low rate and high rate firing to respectively close and open the passage between said air tubes, whereby one or both of said tubes is or are connected to the fan for low and high rate firing respectively.

5. In an oil burner for house heating systems, a motor, an air fan, an oil pump, a. transmission for driving the fan and pump from the motor, two air tubes arranged one within the other with a passage between them, the inner tube being permanently connected to receive air from said fan, valve means operable to connect or disconnect the passage between the tubes to or from the fan, two oil conduits selectively connectible to said pump and each arranged to end with an atomizing nozzle located in the inner air tube in such position that the air from the inner tube and air from the passage between the tubes will mix with the spray emitted from either nozzle, valve means for selectively connecting said oil conduits to said pump to provide for high and low rate firing, and means connecting the first and second valve means for opening and closing the first-named valve means when the second-named valve means is respectively positioned for high and low rate I JosEPn a LOGAN.

REFERENCES crrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,932,269 Harrington, Oct. 24, 1988 1,976,097 Sharp Oct. 9, 1984 2,067,441 Good Jan. 12, 1937 2,120,387 Bargeboer June 14, 1988 2,203,553 Thoresen June 4, 1940 2,315,412 Galumbeck H11. 80, 1948

Images