US2375649A - Oil burner - Google Patents

Description

y 1945- J. R. HAWLEY 2,375,649

' on. B RNER Filed July 21, 1941 3 Sheets -Sheet 1 20 Jim; P/lqwur ATTORNEY y 9 J. R. HAWLEY 2,375,649

OIL BURNER Filed July 21, 1941 3 Sheets-Sheet 2 ATTORN EY Patented a 8, 1945,

Y UT-NIT'E D STATES" PATENT OFFICE 2,375,649 H w I 01L BURNER James R. Hawl ey, SaLttlejWash. Application July 21, 1941, Serial Nil/403,345

2 Claims. (01. Isa-s6) 1 This invention relates to -oil burners, and more U .particularly toloil burners {f the types now generally used in connection with plantsfor the heating of homes, commercialrestablislunents.and for analogous uses, and which are designed for the burning .of What is generally referred to as heavy fuel oil; it 'being :the principal object of this inventionto adapt the principle of atomiza- .and mechanical pressure to small capacity nozzles tion totheuse-ofheavy fueloils by applying heat to insure satisfactory atomization and efiicient operation withoutcoking or-other fouling'of the burner. 1 1 1 i The present invention is a continuation in part 10f the subjectlmatter of my copending application, filed on August 21, 1939, under Serial 291,148, inow Patent 1941. 1 .'It has been recognized-inthe use of. heavy fuel oils that rbetter atomization and greater heating :No. 2,255,318, September 9,

efliciency will-be obtained in the burningopera tion if, the fuel oil,is warmed up before it is atomizedrfor-ignition .in-the combustion chamber. In some burners,.provision has been made for such .heatingof theioil, :but usually, this takes place at some point remote from the ;actual point 1 of atomization. Remote heating isaccompanied by certain disadvantages, which the present inventionhaszovercome.

One of the disadvantages in the preheatingt;

of the fuel oil .at .a point remotelfrom the point of,

atomization, is the resultant loss of heat frornthe .preheatedoil as itliowsto thepoint-of atomization, {and the corresponding loss of burning aefliciency. Where attempts have beenmade to. overi 1 .come this drop in efiiciencyhyapreheating the oil to ahigher degree, there has beennoted the very objectionable .result of cokingof'the oilin the preheating coils, .requiringthatthey be.periodically cleaned of such coke or carbon, or that the mapparatus ultimately be replacedibecause of resultant deterioration.

The cokingtof oil inthe pipes, or tubes in which preheating is eflected, results in small particles 4 of coke being-dislodged from thetube walls and carriedlto the atomizingnozzle, eitherpartially or entirelyclosing its. discharge, orifice and thus rendering *the burner inoperative or inefiicient and presenting a serious .hazard to safety. Furthermore, this'formation ,of coke, and thecloggingof nozzles or valves-frequently results inthe dripping of oil and a further hazard-to safety.

In .view of the above mentioned andother disadvantages ofremote heating .oftthe oil, .ithas beengthe principal object of this invention to provide an oil burner wherein the oil,-delivered from a source of supply remote from theburnenris preheated within 1 the burner itself --to a 1 degree reasonably-close to its vaporization temperature and at apoint immediately adjacent the nozzleorifice whereby it is atomized and. -.discharged into the combustion chamber, thus avoiding those objectionable features of nozzle fouling,.heatfiloss and coking that were previously mentioned.

It is also an object .ofithisinvention torprovide a burner embodying, the features previously men- 'tioned and wherein an oil delivery pipe-leadsfrom the .011 delivery and pressure .pumpto the atomizingnozzle, and a check valve and control valve are incorporated inthis pipe-near the .pLu'np and nozzle, respectively, whereby oil contained-inthe pipe between these valves will .be. confinedunder pressure, thus permitting it to be "brought to a higher temperature, without vaporization or carbonization, and thusinsuring easier and quicker starting of :theburner incident to heating and 1 subsequent. opening of the control valve, 1

Still another 'object of the present invention isto provide-an oil burnerwhich embodies there "in-a -converter *for quick and efiective 'heating of oil thus toreducewith'safety thetimerequired'for pr per starting of the burnertoaminimum.

Another object of "the invention is to provide an extended 'heatingpassage of helical formation in the converter tubeto give maximum efliciency and proper heating of oil'in theminimum time) In accomplishing these and other objectsofthe invention,I have provided theimproved details of construction, the preferred forms of which are fan and fan housing "in horizontal section, anda portion of the airiblasttube broken away.

Fig. 3 is an enlarged, lon'gitudinalsection of the receivingendportion of the converter tube andparticularly illustrating'the mounting of the valve operatingsolenoidthereon i, i

Fig. 4 is an enlarged, sectional detail of the discharge end of the converter, showing the nozzle control valve. 1

Fig. is an enlarged sectional detail of the .Fig. 7 .is a diagrammaticshov/ing or the on pipe connections between source, of supply and converter.

Fig.5 is a cross sectiononline 5-5 in Fig.4.

Fig. 8 is a diagram of the electrical system for the burner.

The present improvement is not intended to be confined in its use to any particular make of burner, but to be applied to all burners which are of a type to which it may be economically adapted. In the typical construction, herein illustrated, the burner comprises a housing containing a fan, driven by electric motor, for the forcible delivery of air through an air blast tube into the combustion chamber of a furnace with which the burner may be associated. Located coaxially within the air blast tube is an electrically heated oil delivery unit to which I will hereinafter refer as a converter tube. Oil is delivered to the converter-tube by means of a motor driven pump, at a constant predetermined pressure and is discharged therefrom into the air blast as it enters thecombustion chamber through a valve controlled nozzle orifice.

The oil is heated in the converter by flow'of' electric'current through a' resistance coil which closely surrounds the oil delivery tube, and to facilitate this heating, the oil is caused to flow through an elongated helical channel leading up to the nozzle. This also causes the oil to reach its maximum temperature at the entrance to the discharge orifice.

The actual delivery of oil from the converter is under control of a valve located at the entrance to the nozzle, and controlled automatically through the energization of a solenoid which. in turn. is under control of conventional or special thermostatic devices; for example, such as were disclosed in the previously mentioned application, Ser. No. 291,148.

Referring now more in detail to the drawings-- In a preferred form of construction of oil burner embodying the present invention, there is a rectangular base section l which mounts a fanhousing ll thereon. The base section is equipped within its four corner portions. with vertical supporting legs Illa, having feet HJb. These legs are threaded through mounting brackets Ilic fixed in the base section and may be vertically adjusted to level and maintain the burner at a set position.

The fan housing ll rests upon and is rigidly fixed to the base Ill and within its upper portions contains a fan M of squirrel cage type; equipped with a hollow hub portion I ia. whereby it is mounted upon the end of the drive shaft lc of an electric motorl5. The motor, in turn, is fixedly mounted upon the side wall of the housing llbyaplatel6.

Air is admitted to the fan through a side wall opening Hm in the housing wall that is opposite that on which the motor is mounted, as noted in Fig. 2.

Mounted on the side wall of the housing H about the wall opening Hm is a bracket l9 and operatively supported by this bracket is a fuel pump designated in its entirety by numeral 18. This pump has a drive shaft I811, coaxially alined and keyed .within the fan hub and effecting a driving connection therethrough with the drive shaft of the electric motor, so that the pump is continuously in operation.

Fixed to the pump housing, at the outside, is an oil filtering chamber 20 connected by a conduit 2| with a source of supply of fuel oil, not herein shown. The intake side of the pump housing, as noted in Fig. "7, communicates through a passage or port 22 with the filter chamber and its outlet port 23 communicates with a duct 23 leading to an adjustable pressure regulating valve 24 from which a feed conduit 25 leads to the receiving end of the converter 26, later to be described in detail.

In the connection between the pressure pump and the converter there is interposed an expansion chamber and strainer, designated in general at 28.

The pump, in operation draws oil from the filter chamber and delivers it at a' predetermined, set pressure, past the regulating valve 24 to the strainer 28 and from the latter to the converter The lower portion of the fan housing H is rectangular in cross sectionjand is slightly larger than the upper portion, converging at its forward side to a cylindrical neck ill) from which a cylindrical air blast tube [3 extends for directing the air supplied by the fan M to the combustion chamber of the furnace with which the burner is used. At its delivery end, the air blast tube is fitted with a nozzle member l3 for concentrating the blast and this nozzle may, if desired, be equipped with fins or deflectors, not shown, for causing a whirling or swirling delivery of the mixture into the combustion chamber.

' Disposed horizintally within the housing II and coaxially of the blast tube 13 is the converter oil heating tube 35. The rearward end of this heating tube extends through the rearward wall of the housing l I and is there provided with a tubular fitting 36 to which the oil delivery conduit 25, leading from the pump l8, connects for supplying oil to the heating tube. At its forward end, the tube 35isequipped with an atomizing tip 38 and this is disposed, as noted in Fig. 1, just within and centrally of the delivery end of the blast tube.

Mounted on a side wall of the housing ll, be-

49 low the motor l5,is a transformer 42, and extending from this are circuit wires 43 and 44 leading into the housing and along the converter and terminating in ignition points 46 and 41 located adjacent the atomizing nozzle and between which points a spark may be caused to jump for igniting the combustible mixture as is the usual procedure.

Mounted upon the fitting 36 and disposed vertically thereon, is a solenoid 46 designed for control and operation of an oil delivery valve at the delivery end of tube 35, as presently will be explained.

As seen in Fig. 3, the solenoid 40 comprises a coil 40' that is enclosed within a housing 48, and is disposed about a cylindrical, liquid-tight, tubular dome '50, which is threaded into the fitting 36. The dome 50 contains a steel block 5| which operates as a solenoid core, and, as here shown, will be drawn upwardly upon energization of the coil.

A link 52 is pivotally connected to the lower end of the core, as at 53, and at its lower end, the link is pivotally attached, as at 54, to a lever 55 used in the control of the oil valve in the converter tube, as presently will be explained.

' The tube 35, as noted in Fig. 3, is threaded into a nipple 56 which is attached to the fitting 36 by a coupling union .51. A tubular fitting,x58 is inserted in the fitting 56 and is held in place by the nipple 56 and the union 51. This fittin 58 is shouldered to limit its insertion in part 36 and forms a leak-tight connectionwiththe nipple 56; and, slidably contained within the coaxial bore 6| in the fitting 58, is a rod 60. It will benoted that the fitting 58 is longitudinally interposed mica ribbon 9|.

. isa coverin 92, of plastic'as'bestos, or the like,

of confining heat in the converter.

amrctcc 3 slotted at its ttp *side and inner-end within-part 35, as at 62, "to receive the end of the lever #55,

52 by a pin -63. iAls0,"itwill be noted that the eiitends through the slot, and *that a notch or "recess 66 "in the lower'edgeof the lever receives The valve device comprises :a valve seat them- "her Nwhiehis threaded, into-a inner end opening provided in the spray tip "38. Continuing from the valve plunger '86 is a valve stem 106 slidably -'contained in a counterbore withinfan inwardly extendingportion of the valve seat member.

The valvestem or plunger Hi6 has *a tapered forward nd portio lllfiaadapted toclose against e p 65 therein. Ports 61 in i the fittin'g "5'8 a valve seat formed byataperedbore "105a inth open into an -enlarged central bore liil for an "unrestricted. passage of oil *therethrough to tube "35. With this arrangement of parts, energizati'on of the solenoid causesan actuation of the lever '55 whereby the rod 6t] will be pulled outwardly.

As will presently be understood, this opens the nozzle valve for delivery of. oil frcm the converter-nozzle.

Disposed lengthwise "within the tube 35 is a filler or spacer tube 10, provided at opposite-ends with closure fittingsl- 'il ll" whichseal the tube -uliquid-tight.j These closure fittingsare provided with-annular outer end portions IL-l2 of a diameter slightly greater than' that of tubef'Hl,

which have an easy sliding fit within the tube 35. These annular pbrtionsflQ-TZ' *areprovided with a plurality of notches orgrooves 1 3- 13 to allow a 'free and unrestricted passage of oil therethrough and about the tube -lil. Further- 'more,the"closures at the twcends-ofthetube "l0 5 are counterbored, as 211315- 1 5 iromtheir outer the atomizingnozzle.fIt willbe understood that.

'upon energization "of the 'solenoid,'the core 5i will be lifted, and the lever will be actuated to pull the tube '10 outwardly, thus to unseat the valve'stem 'fromthe seat Hl5a. Also, upon deenergiza tion. oi the solenoid,*the\core 5| will drop, and this action will'movethevalvestem .to close 'the passage. Flow of oil tothe .nozz'le through fitting 1.05 is permitted .by reason of a plurality valve frornseating.

. .-A.thermostat bulb, designated by reference numer-a1 1.3.0, is disposed, at the outside *oitube ends to a diameter and depth suitableto loosely receive, at one 'end, an 'end portion of theyrod 6G, "and at the other end, the valve plunger-86.

The rod and plunger are fixed in place respectively by pins l6l5. The rather narrow annular passage length of the converter, contains a helical coil of copper wire"8-l. "This wire is of such: diameter that the convolutions of the coil all contact closelywith the tube SllI'fELCQSfilld the convolutions are slightly spaced-apart, so that the coil this wire "coil provides 'an oil channel approxiwhich is formed between the oil tube35 and the filler tube fill, and which extends, substantially the: full ring element. Lbulb .l30 .totransmit..pressure ofaexpandiblemedh ..35.,and nea-rathe discharge end of .the converter -as.in .Fig. 4, This bulb is .in-contactqon one side with .the tube and on .itsother side .withth heat- -A-smal1 .tube 113i leads from the um usedin thebulb .to anadjus-table therm ostatic switch 184 to provide for will presently be explained. a

In Fig. 8, I90 and: designate .power .-lines 1 leading .from a source of low voltage current.

it no while lilt' and littdesignate power lines simply- .ing .high =voltage current. The electric motor -I 5 has one..side connected =b y a line 1.94 with line 133, and .its other side connected by a line .1195

withacontact llls.on.afstackswitch I91. The

, transformer 42 ,has one. side connected :by a .wire

1.98. with the circuit line .193 andlits other-side 1, connected .by awire L99. withithe contactillll cf mate-1y one-eighth 'oi an inch'wideand from 150,

to 190 inches long and presents aytotal of approximately 120 to 180 square inches otheating surface.

Controlledheat is appliedtothe converter tube through 'useof an electrical heating elementf ln "the present instance, I prefer 'to'use a nichrome ribbon elernentfimwhich iswound about the tube dhtoeing electrically insulated therefrom by an 'Overlyin the element whichserves bothas an insulator and a a means the stackswitch.

.The stack switch .has 1 a switch arm connected b a .line .2114 .withline 192, .andcthis arrncom ,prises parts .202 .andldii, adaptedto openor close as .a unit. .and..on=.closihg, .toengagethe contacts Circuit : wires 93 and 94 lead to the opposite ends of theheatingelement. These connect with suitable source of electrical energy which may 'be automatically applied through use-0i ,thera wire 212 .to; a solenoid coil .ZId-of a solenoid.

switch 224, and then through awn-e H241 to one side of a lock-out switch 2M, which has its other side connected by a wire 215 with the line I190.

L96 and"2.ll0 and simultaneously close the high voltage circuitthroug'h motor 1.5 and the transfornier 142. The switchmen'ibers 2G2 and 2.03 are operable to closed position solenoid {205 having a circuit connection 206with line"l and a connection 201 through atime.

delay switch "268 which will electrically connect the wirezfll with a circuit lwire ZUQleading to e0 circuit wirel9l. l

The room thermostat, which is generally the instrument under which automatic control of the burner is placed, is designated .at 290, and has one side connected by .a ..line v2! l with circuit line ESL and its other side connected through The time delay switch 208 includes a heating element 220 which functions when current is passed therethroughto heat a bi-metal strip to effect the closing of switch 208 and thus connect the lines 201 and 209 and energize the solenoid coil 205 in the stack switch I91. This solenoid .under control of a .the stack switch is not affected by the heat of combustion.

In heating a home, when the room temperature falls below that for which the room thermostat H is set, the switch 2l0a therein closes, thereby energizing the solenoid coil 2E3 in the relay 224 which causes the closing of the switches 225 and 226, These latter switches close the circuit to the burner thermostatic switch I84 through the lines 229 and 230, and to the time delay relay switch 208 through the lines 232 and 233.

The oil heating element 90 connects with the switch I84 through wires 93 and 94, and the circuit is completed through the normally closed switches IBM and 18419 to energize the heating element. Upon the heating of the element, the heater tube and the oil contained therein finally reach a certain predetermined temperature, and the thermostat bulb operates through the connecting tube l3l to open the switches I 840. and I841) in the switch I84. When the converter falls below a certain predetermined temperature, the

thermostat bulb operates to close the switches to maintain a circuit that keeps the oil at a substantially constant temperature.

Simultaneous with the energization of the oil heater element, the time delay relay heater ole-,

ment 220 is energized, and after a predetermined period of time, the switch 208 is actuated to a closed position, thereby closing the circuit to the solenoid 205 in the stack switch. During this period of time, the heater element is heating the oil in the tube 35 to the point where atomization for combustion is most readily established and maintained most efficiently and economically. When the solenoid 205 in the stack switch is energized, it operates to close the switches 202 and 203 whereupon the circuits are closed both to the valve operating solenoid 40 and to the motor, thereby opening the valve andv starting the pump, for the delivery of fuel under pressure, and a blast of air through the tube l3 to support combustion, at the same time furnishing current to the ignition transformer for ignition of the fuel mixture. Upon combustion being established, it will continue until one of the controls automatically calls for a shut down. The heating element, however, will remain energized to heat the oil to a predetermined temperature,

or will be turned off and on intermittently to maintain a substantially constant heat under control of the thermostat bulb and the switch I84.

In a normal operation, when the room thermostat 2K0 is satisfied, the switch 2l0a is opened,

thereby lie-energizing the solenoid coil 2l3 for 2 opening the switches 225 and 226 in the relay 224.. This opens the circuit to the heater, and the time delay relay element 220. However, in this construction, the time delay relay will not open for a predetermined interval of time, thereby maintaining the operation of the motor l5, the pump 20 and holding the valve solenoid energized until the circuit is opened. This allows the burner to scavenge itself of hot oil in the heater tube and dissipate the heat of the tube itself. This provides that the oil temperature in the tube will be reduced and that the tube itself will be cooled to a safe temperature below which coking of the oiltherein will not take place.

The particular advantages of this burner are to be found in the provision for heating the oil adjacent its point of use and to a maximum at the nozzle. Also, in confining the oil under pressure at all times between the nozzle and pump so that at the instant the nozzle is opened, the oil is at atomizing pressure, thereby beinginstantly ignitable, and preventing dischargeof oil into the firebox before ignition takes place, as would be the case in the event that an atomizing pressure had to be built up after the nozzle valve was opened.

Having thus described my invention, what I claim as new therein and desire to secure by Letters Patent is: I

1. In an oil burner of the character described, an oil delivery tube, an oil atomizing nozzle at the discharge end of the tube, a control valve in the tube adjacent thenozzle, a filler tube operatively connected with the valve, for actuating it between open and closed positions, and positioned in the oil delivery tube centrally and coaxially thereof and setting off an-annular channel between the tubes for the passage of oil to the nozzle, means for supplying oil under pressure to the receiving end of the delivery tube, a helical wire coil interposed in the annular channel and extending substantially the length of the tube and contacting with the surrounded and surrounding tubes throughout its length to provide a continuous helical channel for flow of oil to the valve, and means for shifting the filler tube for actuating the valve between closed and open positions.

2. In an oil burner, of the character described,

I an oil delivery tube, an oil atomizing nozzle at the discharge end of the tube, a control valve in the tube adjacent the nozzle, a filler tube operatively connected with the valve for actuating it between open and closed positions, and positioned in the oil delivery tube centrally and coaxially thereof and setting ofi an annular channel between the tubes for the passage of oil to the nozzle, a solenoid mounted upon the delivery tube at its receiving end and means in the tube operatively connecting the solenoid with the filler tube for actuating the valve between closed and open positions and a circuit for operating the solenoid.

JAMES R. HAWLEY.

Images