US2658567A

US2658567A - Oil burner

Info

Publication number: US2658567A
Application number: US120801A
Authority: US
Inventors: Robert R Witherell
Original assignee: EUREKA WILLIAMS CORP
Current assignee: EUREKA WILLIAMS Corp
Priority date: 1949-10-11
Filing date: 1949-10-11
Publication date: 1953-11-10
Anticipated expiration: 1970-11-10

Description

Nov. 10, 1953 R. R. WITHERELL OIL BURNER 3 Sheet-s-Sheet 1 Filed Oct. 11, 1949 INVENTOR. R l l z z f/e/ezl NOV. 10, 1953 R HE LL 2,658,567

OIL BURNER Filed Oct' 11, 1949 3 Sheets-Sheet 2 All INVENTOR.

Nov. 10, 1953 R. R. WITHERELL OIL BURNER 3 Sheds-Sheet 3 Filed Oct. 11, 1949 INVENTOR. Raid/-2 z w z je/ell.

Patented Nov. 10, 1953 UNI T OFFICE 2,658,567 OILBURNER Rob'eit 7R. Witlierell, Blouhihig'fiim 111., assig tir to ElirekaWilliams Corporation,"=Bloomington,

-Ill.,':a, corporation of Michigan 9 Claims.

This invention relates to oil burners and has particular referende"tocertain new and useful improvements which "relate to oil burners of the 'low pressure'type wherein oil and'airare supplied under a relatively'lowpre'ssure to an air mixing nozzle which'discharges the mixture into'a secondary airs'train. While burnersofthelow pressure type have been "manufactured and sold for a'conside'rablefperiodof time, they have in general been'relatlvely expensive. This invention has particularrefeiienoe to" a eonstruotionfor a burner of this typewhich is of relatively low capacity and whiohr'na'y 'be manufactured ata lower cost than burners of this type "which have been heretoforeavailable. 7

An oilburner'embodying the in'ventionoomprises in 'generaFa "tubularc'asing, one end "'of which 'isadapt'edto be arranged'in communication with a combustion chamber for discharging a combustible miii'tiire or oil and air "nto such cembushoh chamber. The other "eh or the casing'isprovided with 'iiiletopeningfor admitting air thereto, j'aiid ithih the "casii1g there "are arranged "ah electric hitter, a fan, air pump, an oil supply ipiimp, an on hitenn' pump, an oiland'air'miiiingiiozzle,theeleotiodes or "an ignition for igniting thehiixtura and suitable valves and other appurtenances forming a art "of the operative meehanism of theburner, the parts hamed'beinga'rranged "a line within the "easing and the easing forming a housing as well "as a conduit thr'oii'g'h which secondary "air is supplied past the 'nbzz'leto the combustion chamber.

A principal obj e't "of the invention is "tof'provi'de a new and "improved eons'truction for oil burners. V I

Another object or "the finvention'is 'to provide a novel andfirrl'pr'ovd m1 and "air supplying arrangement'foroilbifrners.

Another object it the invention is "to provide aneffioient, low-cost, low capacity, 'hig'h quality, power-operated'oilburner. I I

Other and further objects of the invention will be apparent from the following description and claims and will be funderstood fby *refe'rehee to the accompanying "drawings, of whioh there are three sheets, whioh by way'of illustration show a preferrederiib'odiment aiidthe principles thereof and what "I now consider to be the {best mode in which I have 'ooiite ihplated iapplyi'ng those principles {Qtherei'i'ibodiinht'sfof thIeJinvention"embodyiiigtlrefsahie o r e qu 1 cipl'esmay be used and strubtu'ral "oh'a ges may be made as desired b'y those skilled in -the a'it "without 'departing from the "present invention 'and'the purview of 'the'appended claims.

vIn the drawings: V I I Fig. 1 isalongitudinal sectional view of an oil burner embodying the invention;

pump taken along the 'line"4- 4 of Fig.1;

"Fig.5"is a sectional view of a pressureregula'ting valve taken along the 1ine*5-5 of Fig. 1;

-"6 is a sectional view of the metering pum taken'along the 1ine'f6-T6 of Fig. 1; and

"Fig. 7 is a sectional "view through "the oil and air mixing nozzle 'taken'along'the'line l! 'of 'Fig. 1. Y

As shownin'Fig. 1, "an oil burner embodying the invention comprises in general a tubular casing I!) having a nozzle or opening I2 in communication with a combustion chamber and through which opening! 2"a stream of air charged with atomized oil is discharged into the combustion chamber. Within the housing [0 there is arranged an air and oil pumping and mixing unit which comprises a fan [4, a motor [6, an

:air pump 20, an oil supply pump l8, a centrifugally responsive valve: I, an'oil metering pump 22,

a pressure-operated, normally closed valve 24, an 'oil' and airmixing nozzle 26, and'igniti'on electrodes 28. {p I The'e'asin'g 36 ofthelmotor is supported by a pair of resilient rings 32. The metal rims 34 of the rings '32 are 'su'pported'in 's'pac'ed'relation to the interior of the casing l O'by a plurality of fins 3% which extend longitudinally of the casing 10 on the interior thereof, thereby providing an annular air conducting passage 38 between the motor casing 30 and the 'inte'rior'of the casing ID. The motor casing 30 may be provided with a plurality of integral heat dissipating fins 4 0 'extending into the passage 38 to aid in'dissipating the motor heat. The 'motorcasing houses the usual field and armature and bearings for the shaft '42 which projects beyond the casing 30 "and at'one end thereof has the fan I4 seeured thereto. The end of 'the'casing 's'fn adjacent the "fan is formed to provide a cavity '4'4 withinwhich a speed responsive switch indicated generally at 46 isarranged.

v The switch 45 is mounted on the shaft 42 between the fan I' l an'dthe motor '6 and is of the type whichris adapted to cut out the starting windings of the motor when the "same approaches its normal running speed. The switch 46 is shown in its position with the starting windings cut out of the motor circuit. The centrifugal switch is of the type disclosed in the application of Kemper M. Hammell et al., Serial No. 676,885, filed June 15, 1946, now U. S. Patent No. 2,573,968, for Centrifugal Switch.

The casing I is provided with an air inlet 48 opposite the center of the fan I4, and an air valve indicated generally at 50 is arranged ahead of the inlet 48 so that the air intake to the fan may be regulated. The valve 50 comprises two perforated discs 52 and 54 pivoted together by rivet 56 so that the perforations in the discs may be moved into or out of registry with each other in order to increase or decrease the supply of air to the fan I4.

The motor casing is provided with a socket 58 accommodating a thermostatically operated safety switch 66 which is arranged to open the &

circuit of the motor It in the event of overheating thereof. This switch may be of the type disclosed in Samuel E. Vickers Patent No. 2,473,485, issued June 14, 1949, for Thermal Overload Device, and needs to be manually reset. To this end a diaphragm 62 is incorporated in the casing If} opposite the reset button 64 of the switch 66 so that if the switch opens, it may be reset after the motor has cooled down.

The motor shaft 42 also extends beyond the motor casing 65 in the other direction and is connected to the air pump 20, the oil supply pump It, the centrifugally responsive valve 2 I, and the metering pump 22 for operating the same.

It should be noted in connection with Figs. 0

1 and 2 that the passages or ducts as shown are illustrated somewhat diagrammatically in order to illustrate the system and the fluid connections between the various parts of the oil burner, while in Figs. 3, 4, 5, 6 and '7 the sections are of the burner as actually designed.

The right hand end of the motor casing 3t) is formed by a frame having a cavity 68 exposed to the interior of the motor casing 33. The air pump 29 is disposed within this cavity and comprises plates I6 and I2 with cylinder "I4 secured therebetween, such plates and cylinder '14 defining the pump chamber I6 (Fig. 3). The air pump 23 is of the rotary sliding vane type and further includes a rotor i6 mounted and keyed to the shaft 62 and having a series of radially extending slots in each of which a vane 88 is slidably arranged so that upon rotation of the rotor air will be drawn into the pump chamber I6 through the inlet 82 thereof, compressed, and discharged under the regulated pressure through the discharge 84. From the discharge 84 air is conducted through the passage or duct 86 to the nozzle 26.

The shaft 42 extends through an opening in the rotor 18, and a pin 88 disposed in a hole through the shaft 42 and in a slot 88 in the rotor I6 keys the rotor I8 to the shaft 42 for rotation therewith. A seal 62 for the shaft 42 is disposed in a socket 94 formed in the pump plate I6. A fiexbile diaphragm 96 is clamped by the plate 12 to a wall or partition as of the frame 66, and the plates 16 and I2 and the cylinder '54 are clamped in the assembly as shown to the partition 98' by bolts I00, the ends of which are threadedly secured in threaded openings in the partition 68.

The pump 20 is provided with a by-pass comprising ducts I62 and I84 between the discharge 64 and the inlet 02, and this by-pass is con- 4 trolled by a valve I66 which is adjustable so as to regulate the discharge pressure of the pump 20. The pump inlet 82 communicates with the cavity 68 which may be supplied with air through a series of ports H0 in the motor casing.

The partition 98, plate I2 and plate H2 cooperate to define a seal and bearing chamber H4. The bushing H6 of a self-aligning type of bearing is seated in a socket H8 formed on the plate H2, and a spring plate I20 seated against a shoulder in the chamber H4 forms a socket for the other end of the bushing I I6 and confines the same against the seat provided by the socket H8. Shaft 42 is journaled in the bearing bushing H6 and projects therebeyond.

A running seal indicated generally at I22 is arranged between the partition 98 of the frame and the shaft 42 and includes the diaphragm 66, a coil spring I24, a bushing I26, a seal ring I28, a cup-shaped sealing ring I30, a ring I32 of resilient material, a washer I34, and a snap ring I36. The ring I32 of resilient material is arranged inside of the cup-shaped ring I30 and forms a seal between the ring I30 and the shaft 42. The ring I30 rotates with the shaft 42 and is held in position by the ring I32, the washer I34, and the snap ring I36 which is anchored in a groove in the shaft 42.

The seal ring I26 and an annular radially extending portion of the bushing I26 clamp the edges around the opening through the diaphragm 66 therebetween, and the other end of the bushing I26 is expanded over the seal ring I28 so as to anchor the two parts together. The surface of the seal ring I28 and the contacting surface of the sealing ring I36 cooperate to define a running seal about the shaft 42 so as to prevent the flow of oil from the chamber H4 into the air pump housing.

The shaft 42 beyond the bearing H6 is hollow and extends into the discharge chamber I40 for the oil supply pump I8. The plate H2 cooperates with a sleeve I42 and the plate I44 to define the discharge chamber I40 in which the oil supply pump I8, the centrifugally responsive valve 2 I and the metering pump 22 are arranged. The plate H2 is seated in a cavity in the frame 66, and the sleeve I42 and the plates I44, I46, I48 and H2 are bolted in assembled relation as shown to the frame 66, preferably with gaskets between adjacent faces of the parts so as to form an effective seal between the portions of the ducts and passages which extend through such parts.

The oil supply pump (Figs. 2 and 4) may be of the gear type and comprises gears I50 and I52, the latter being keyed to the shaft 42 so as to rotate therewith. The gears are arranged in a pump chamber I54 provided with an inlet I56 and an outlet I58, the teeth of the gears being in mesh and the gear I50 being rotatable on a shaft I60. The pump chamber I54 is defined by a block I62, the plate H2 and a plate I64 suitably secured in assembled relation by bolts I66. The pump outlet I58 opens into the discharge chamber I40. The inlet of the pump I0 is supplied with oil from a suitable reservoir throu h duct or passage I68.

A filter assembly I10 is arranged between the pump I8 and the oil supply tank and is provided with an inlet port I I2 to which the fuel line from the oil tank is connected and an outlet port I14 which is connected by a conduit to the oil supply tank to return excess oil thereto. Upon entering the filter unit I10 the oil flows through duct I16 .ductfI84 which'is connectedlbya fuel'jlineindicate'd diagrammatically at I86 to .the .duct l I 68 for supplying .oil ',to the suction pump I8.

lThejfilter unit I'lfllalsolincludes .a .duct [88 which is connected. byifuel lineiI'QIl to duct I92 which communicates .with 'the seal ...and bearing chamber I' I4. lDuct .[92,Iline IISILandJduct I88 "form .part ofra lbyepassvfor the .suction .pump

I8. The duct I 88.communicates pastcheckvalve I94 with .duct I 96 whichiisin communication with port I14 whereby .thelexcess oil ,pumped by the pump I8 may'bereturned to theoil tank. If the .threadedplug L98 which I is shown obstructingj the-passageIbetween the ducts I I84 and "l88visnremoved and the port. II4 Jis,p1ugged, the

byepasse'd oil-willliowldirectlyfromtheduct I88 into theiduct I 84. 'This.is'analternative-arrangemerit for the .Lby-z-pass.

"The .,pressure -regulating valve 2I "and the metering pump 22 are arranged in the discharge chamber I49. --A rotor 2Ilfliis keyed on thehollow extension 2 202 of the: shaft 42. The right hand face "204 of V the. rotoris: a. lapped face andseats and rotates against alsiniilarly-lapped face 2% formed on the. .plate I44. Aball208is-seated in theendof the'hollow portionl2-ll2 ofthe shaft and in a socketlinthev rotor .200. Thevsealspring I24 reacting through the seal and the shaft 42 .and the ba1l"208 .biasesvthe rotor\200 against the face 206 on the: plate I 44.

.The rotorZOIl isprovided with a diametrically .extendingbore "2H1, oneend of which is closed by plug 2I2. The other-end-of the bore.ter

minatesin a reduced opening forming a port 2 I 4 betweenthe discharge chamber I-4lland the valve chamber. 2I6 formed by the bore within therotor 200. The valve chamber-H6 is in-communication with the-interiorfiof the hollow portion 202 of the shaft 42. 'A .ball valve ,2I8Jis'arranged .in a cage 220 inthevalve chamber-2H6. Apin HZ-projecting from; the plug2 I2 retainsthe ball the port :2I4,;the valve chamber-'2I6,'the"ho1low portion of the shaft 202, the-cross duct224, the

seal and bearing chamber I I4, and the duct I92 Iform part of a bypass between the discharge and inlet sides of-thel pump I8, and flow through'this :by-pass-is controlled by the centrifugally respon- "sive valveZI which includes the rotor 2%, the prt'2 il,the valve member ZlS and the 'seatfor -the valve '2 I 8 formed bythe inner edge of theport 2I4. When-the shaft 42'is not rotating, the ball valve member 2I8 'is'unseate'd so that'the port 2M is open. However, rotation of the shaft 42 and of the rotori200 will .cause the valve vmember '2I'8 under the infiuenceof centrifugal force to move outwardly toward .its seat to restrict ,or close'the port 2".

Thepumpl22 includes cylinders 230 and-232 formed by a diametrically extending bore in the rotor 200, the bore being divided into the cylinders 23B and 232 by therplug 234 which is arrangedat the center of the bore. .Apin23ii is slidablytarranged in the,plug 2234. A piston 238is arrangedwinthe cylinder 232 and a piston 240is arranged in the cylinder 230. A ring'242 surrounds the-rotor 200 and is eccentrically disposedwith'respect thereto. The outer ends of thepistons ,240and 238 vbearzagainst the inner periphery of the ring 242. The piston 240 inwill always bear against theinner periphery of the ring 242. As the ring:2 i2 istdisposedi offcenter relativeto thevrotorifiil, it willbeevident that upon rotation of the-rotonthe :pistonsldfl andztt willimove in andout in .their.respective cylinders, and when-the piston 238 is arranged as shown inFigSVZ-and 6 the cylinder 232 will be in communicationwith theoil inlet port .250 which communicates through duct 252 with the discharge chamber 440. At the same time the cylinder will .be invcommunication withthe discharge port=2 51% which communicates through ductZEG-with the valve chamberi 59. Thus, upon rotation of the rotor 2il0 the cylinders 230-and 222 will alternatelybebrought into registry with the oil supply port.=25l and supplied with oil, and such cylinders also will be'brought alternately into registry withlthe discharge port .254, and the pistons, due to -.-the eccentric arrangement of the ring 242, willeefiect the discharge .of oil, from the cylinders through the discharge port and .duct 25% intothevalve chamber 259. Thepressure operated, normally closed valve comprises a flexible diaphragm 2-7!) which is ramped between plates. M l-and I46 and which separates valve chambera260; from valve chamber The diaphragm 210 .has secured vto it a valve body 2T4:whichisHslidable'in-a cylinder the body 2M being, provided with an annular groove in which an o-ringilB is arranged and which forms a seal between @the cylinder 21-6 the valve body=214 soras'to separate valve chamber 2597-. from valve chamber 259.

The valveibody 2'I i-isprovided with a hollow valve stem 2% having ports 282 which in .the position shown are .in. communication with the valve chamber 2559, thereby ,-providing for the flow of metered oil lfrom -.the duct 258 \through the ports 232, the hollow valve :stem 2 80, and the .pipe 234 intothe nozzle-"26.

The valve stemleil is slidable in the=bore 236. Thevalvestemflfiiiis madeFso as. tohave-approximately 1005 inch clearancezin relation to the bore 285 and "which: clearance serves as a metering orifice to :allow a small amount 0f oil ;to fiow from the chamber 259 to the duct 28-.Nwhich diaphragm 226 so as to urge the valve body 214 toward its seat .292,.thereby to.close the valvel24. Oil under pressure supplied to thechamb'er 222:8

throughthe ductiiid fromfthedischargechamber 123 will act on the diaphragm 2I'Il'and'open the valve 24 In the burner. illustratedlthe centrifugal pressure regulating valveis constructed and arranged to-maintain apressure in thediseharge chamber Hit of from 12 to 14 p. s. i. (pounds per square inch) during normal burner operation. This vpressure, however, :falls roff "very rapidly :whenthe burner motor .falls below the normal running speed -:of the motor, rand lwhen the motor is at rest the pressure in the discharge chamber M is entirely dissipated. The valve 24 is set to open at a pressure of 7 p. s. i. applied to the diaphragm 210, and closes when this pressure drops to p. s. i. This differential probably is caused by the drag of the O-ring 218. The pressure at which the valve 24 operates can, of course, be changed by varying the loading of the spring 290.

The valve chamber 212 communicates through duct 300 with the seal and bearing chamber H4. During operation of the pump 22 before the valve 24 opens, the pressure of the oil in the duct 256 will cause the face 204 of the rotor 20!) to move slightly away from the face 206 of the plate I44, thereby permitting the oil discharged from the pump 22 to escape back to the discharge chamber I40. When the valve 24 opens, oil is supplied through the valve stem 280 and the bore 280 and the pipe 284 to oil ports 302 in the nozzle 26.

The oil ports 302 discharge jets of oil into the air passages 304 which are supplied with air from the pump 20 through the duct 86. The nozzle 2% is constructed and arranged to mix the oil and air and to discharge such mixture through the pressure in the chamber 260 is partially dis sipated, which occurs immediately as soon as the shaft 42 and the rotor 200 fall below a predetermined speed of rotation. In other words, on deceleration of the rotor and the shaft 42 from the normal running speed thereof, the ball valve 218 will move to an unobstructing position relative to its seat on the port 214 as soon as the shaft 42 falls below, say for example, 75% of its normal running speed.

In the oil burner herein disclosed, the normal running speed of the motor and shaft is approximately 3450 R. P. M. The movement of the valve 2! to an unobstructing position relative to the port 2! will dissipate the pressure in the discharge chamber I40 and in the valve chamber 260 and permit the spring 290 to close the valve 24 by moving the same to its seated position.

The following table computed from the laws governing centrifugal force illustrates the corresponding operating pressures that can be generated at various angular speeds:

Percent of Normal Hydraulic Pressure Percent of Angular Speed In this instance, resistance to flow is created by directing the rotated mass of the ball valve 2|8 against the fluid stream flowing into the chamber 216 through the port 2 so as to generate hydraulic pressure in the chamber [40 as a function of the motor speed, the pressure generated being transmitted and directed against the actuating diaphragm 210 of the shutoff valve 24. Thus the shutoff valve is hydraulically actuated and is designed to be opened and closed in response to the changes in pressure developed in the chamber I40 by the pressure regulating valve 2|. Thus, closing of the valve '24 will cut off the supply of oil from the metering pump 22 to the nozzle 26 as soon as the motor speed falls below some predetermined percentage of its normal running speed.

It should be noted that the motor, pumps and valves and fan form an elongated unit which is arranged in the casing ID in spaced relation with the walls thereof and that such unit is mounted in the casing l0 which is adapted to be mounted directly on the wall of the combustion chamber around the opening through which the nozzle end of the burner projects into the combustion chamber.

While I have illustrated and described a preferred embodiment of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. In an oil burner, oil pumping means having an inlet and a discharge chamber arranged to receive oil discharged by said pumping means, a rotor in said chamber, said rotor having a valve chamber provided with a port which communicates with said discharge chamber, a valve seat within said valve chamber, a centrifugally response valve member movable in said valve chamber, upon rotation of said rotor, toward said valve seat to seat thereon and close said port, a communication between the interior of said valve chamber and said inlet, a fuel metering pump having its inlet communicating with said discharge chamber so as to be supplied with fuel therefrom, a motor driven shaft arranged for driving said fuel metering pump and said pumping means and rotor, said shaft being hollow and forming a part of said communication, an oil and air mixing nozzle, a fluid connection between said nozzle and the outlet of said fuel metering pump so as to supply fuel from said metering pump to said nozzle, means for supplying air to said nozzle, a pressure operated normally closed valve in said connection constructed and arranged to be opened by the liquid pressure in said discharge chamber, said port, valve chamber and communication forming a by-pass between said inlet and discharge chamber of said oil pumping means, said valve member when seated closing said by-pass, the movement of said valve member towards said seat under the influence of centrifugal force being resisted by the fluid flow through said port.

2. In an oil burner, fuel pumping means having an inlet and a discharge chamber arranged to receive fuel discharged by said pumping means, a rotor in said chamber, said rotor having a valve chamber provided With a port which communicates with said discharge chamber, a valve seat within said valve chamber, a centrifugally responsive valve member movable in said valve chamber, upon rotation of said rotor, toward said valve seat to seat thereon and close said port, a communication between the interior of said valve chamber and said inlet, a fuel metering pump having its inlet communi catingwith said discharge-chamber so.- as -r to be 1 supplied with: fueltherefrom, a l-motor. driven; shaft arranged for driving; said: fuel: meteringpump, said. pumping meansand-trotor, said shaft being hollow and ,formingpartofsaidcommuni 5 cation, a fuel andiain mixing nozzle constructed: and arranged: to 1 mix fuel and aair and to dis? charge almixture of fuellandair, ,QAfiHidCOIlDECL" tionbetween said nozzle and the outlet."' of said; fuelmetering pump so-astosupply; fuelfrom said metering pump to saidnozzle, means for supplyingair to saidnozzlefor mixture with the fuel supplied thereto; a normally closed valve in said'connection constructed and arranged to be opened. when. the pressure in-- said discharge chamber attains a predetermined amount, saidmetering pump including.provisions for returning the oil discharged thereby to saiddischarge chamber when said valve is closed, said port; valve chamber andcommunication forming a bypass between the inlet and discharge chamber of said pumping means, said valve member when seated closing said by-pass,-the movement of said valve member towards saidseat under the infiuence of centrifugal forcebeing resisted by the fiuid flow throughsaid port; and means for flowing a\ stream ofsecondary air past said nozzle and-into which-stream said mixture of fueland 'air is discharged.

3.: In arr-oil burner, oil pumpingmeans having an inlet and an outlet, an'd'a b'y-pass therebe tween, a centrifugall responsive valve constructed and arranged to resist flow of oil through said by-pass during operation of said pumping means thereby to createa pressure=dif ferential between said inlet and outlet, a fuel metering pump having itsinlet connectedto theoutlet of' saidpumping means so=as tobe-supplied with oil therefrom,- arr oil and air mixing nozzle connected to said mete-ring pumpso as-to 40 be supplied with oil therefrom, a pressure operated normally closed valve in the connection between said nozzle and said metering pump, said pressure operated valve being constructed and arranged to be opened by the pressure differential between the inlet and outlet of said pumping means created by said centrifugally responsive valve, said pump, pumping means and centrifugally responsive valve being arranged to be actuated simultaneously, means driven with said pump and pumping means for supplying air to said nozzle for mixture with the oil supplied thereto, and means for supplying a stream of air past said nozzle into which said nozzle discharges a mixture of oil and air, said oil burner includ- 65 ing a tubular casing having an air inlet at one end and an outlet at the other end at which said nozzle is disposed and from which other end said stream of air charged with said oil mixture flows, said pumping means, metering pump, centrifugally responsive valve, nozzle and air supplying means forming a unit and being arranged in line in said casing.

4. In an oil burner, oil pumping means having an inlet and a discharge chamber arranged to receive oil discharged by said pumping means,

a rotor in said chamber, said rotor having a valve chamber provided with a port which communicates with such discharge chamber, a valve seat within said valve chamber, a centrifugally responsive valve member movable in said valve chamber upon rotation of said rotor toward said valve seat to seat thereon and close said port, a communication between the interior of said valve chamber and said inlet, a fuel metering pum in and having its inletr communicatingg with said: discharge-chamber; so, as -.to be supplied withfuel therefrom, said. rotor; forming part of'said fuelmeteringpump, amotordriven shaft fori'drivingsaid fuel metering, pump andsaid pumping meanscand; rotor, saidshaft being hollow' and f orming arpart-of said, communication and being connected. u) said rotor, an. oil and air mixing nozzle,. a. fluid. connection between said nozzle andftheoutletiof..saidv fuel metering pump so as to supply, fuel.-.from. said metering pump to-said nozzle, apressure operatedlnormally closed-valve in. said connection constructedwand arranged to be, openedlwhenth'e liquid pressure insaiddischarge: chamber reaches a predetermined. amount; said port; valve chamber and communication forming aby-pass between saidinletin an inlet'and a'discharge chamber arranged to" receive fuel discharged by said pumping. means; a rotor insaid chamber, a centrifugally.

responsive"valve carried' by said rotor and actuated upon-rotation thereof, a fluid communicationbetween said-discharge chamber and said inlet controlledby said valve, a fuel metering pump carriedb'y'saidrotor and having its inlet communicating with' saiddischarge chamber so as to besupplied" fuel'therefrom, a motor driverrr shaft' arranged for driving said fuel metering pump, saidfpumping means and rotor, saidtshaft beinghollow 'and forming part'of said communication, a. fuel and" air mixing nozzle constructed and arranged to mix fuel and air andto" discharge a 'mi-xture" of fuel and' air; a fluid connection between said nozzle and the outlet of said fuel metering pump so as to supply fuel from said metering pump to said nozzle, air pump means driven by said shaft for supplying air to said nozzle for mixture with the fuel supplied thereto, a seal chamber surrounding said shaft and disposed between said air pump means and said fuel pumping means and forming part of said communication, a seal in said seal chamber about said shaft and preventing oil flow along said shaft to said air pumping means, a pressure operated normally closed valve in said connection constructed and arranged to be opened when the pressure in said discharge chamber attains a predetermined amount, said communication forming a by-pass between the inlet and discharge chamber of said pumping means, said centrifugally responsive valve when seated closing said by-pass, the movement of said centrifugally responsive valve towards its seat under the influence of centrifugal force being resisted by the fluid flow through said by-pass, and means for flowing a stream of secondary air past said nozzle and into which stream said mixture of fuel and air is discharged.

6. In an oil burner, oil pumping means having an inlet and an outlet, and a lay-pass therebetween, a centrifugally responsive valve constructed and arranged to resist flow of oil through said by-pass during operation of said pumping means thereby to create a pressure differential between said inlet and outlet, a fuel metering pump having its inlet connected to the outlet of said pumping means so as to be supplied with oil therefrom, an oil and air mixing nozzle connected to said metering pump so as to be supplied with oil therefrom, a normally closed valve in the connection between said nozzle and said metering pump constructed and arranged to be opened when the pressure differential between the inlet and outlet of said pumping means created by said centrifugally responsive valve attains a predetermined amount, said pump and pumping means and centrifugally responsive valve being arranged to be actuated simultaneously, means driven therewith for supplying air to said nozzle for mixture with the oil supplied thereto, and means for supplying a stream of air past said nozzle into which said nozzle discharges a mixture of oil and air, said oil burner including a tubular casing having an air inlet at one end and an outlet at the other end at which said nozzle is disposed and from which other end said stream of air charged with said oil mixture flows, said pumping means, metering pump, centrifugally responsive valve, nozzle and air supplying means forming a unit and being arranged in line in said casing.

'7. An oil burner air and oil pumping unit comprising an electric motor having a shaft projecting from both ends thereof, a fan on one end of said shaft, an air pump, an oil supply pump,- a centrifugally operated valve and an oil metering pump arranged in the order named and connected to the other end of said shaft so as to be driven thereby, a discharge chamber into which said oil supply pump discharges and in which said oil supply pump, said centrifugally operated valve and metering pump are disposed, a seal and bearing chamber about said shaft and between said air pump and oil supply pump, a seal in said chamber and disposed about said shaft, said seal chamber forming part of a by-pass between said discharge chamber and the intake of said oil supply pump,

said centrifugally operated valve being arranged in said by-pass and operable for controlling the flow of oil therethrough, the intake of said oil metering pump being in communication with said discharge chamber, an air and oil mixing nozzle connected to said air pump and oil metering pump so as to be supplied with air and oil, said nozzle being arranged at one end of said unit, and a pressure operated valve operatively disposed in the connection between said metering pump and nozzle and opened by a predetermined pressure in said discharge chamber.

8. An oil burner according to claim 7 wherein one end of said shaft is hollow and forms part of said by-pass.

9. An oil burner according to claim 7 wherein said metering pump includes provisions for bypassing oil discharged thereby to said discharge chamber when said pressure operated valve is closed.

ROBERT R. WITHERELL.

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