US2156405A

US2156405A - Oil burner

Info

Publication number: US2156405A
Application number: US55469A
Authority: US
Inventors: Theophilus H Smoot
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-12-20
Filing date: 1935-12-20
Publication date: 1939-05-02
Anticipated expiration: 1956-05-02

Description

T. H. SMQOT May '2, 1939.

OIL BURNER Fil'ed Dec. 20, 1935 3 Sheets-Sheet l I I-ll III III I'I T. H. SMOOT May 2, 1939 SSheeqs-Sheet? mum T. H. SMOOT May 2, 1939.

OIL BURNER Filed Dec. 20, 1935 s Sheets-Sheet 5 Patented May 2, 1939 UN lT ED: STATES PATENT OFFICE Theophilus H. Smoot, Baltimore, Md. Application December 20, 1935, Serial No. 55,469

4 Claims.

This invention relates to fluid fuel burners of the pressure-type wherein ,a jet of fluid fuel, such as oil, is ignited and mixed with a stream of air issuing from the nozzle of the burner.

Heretofore in the art of pressure type oil burners and the like the customary practice has been to ignite the oil and mix it with air issuing from the nozzle end of a blast tube through which air isforced under the pressure of a fan, the fan being housed in a casing provided with a shutter controlled opening through which air is admitted, the volume of air being regulated by adjustment of the shutter means on the inlet side of the fan.

This prevalent practice of the prior art results in a lowered efficiency as the air propulsion means works against a partial vacuum'on its inlet side and which is created by closing movement of the air volume regulating means.

An object of the present invention is to provide an air blast fluid fuel burner provided with. air volume control means located on the air discharge side of the air pump.

Another object is to provide in a burner 01 such character means for obtaining uniform air pressure within the'air blast tube.

A further object is to provide in a burner of this character novel means for regulating andcontrolling the air flow.

Other objects will be apparent from the description, among these being to provide novel structural details of assembly together with means for imparting directional movement to air within the blast tube whereby upon issuing from the nozzle the air is caused to expand uniformly under the action of centrifugal force.

The present disclosure constitutes an exposition of a practical structural embodiment by which the invention is reduced to practice. It is to be understood that the details as shown and described are capable of variation within any limits not inconsistent with the scope of the invention as claimed.

In the drawings:

Figure l issubstantially a vertical longitudinal f section through a burner constructed in. itCGOl'd.

ance with the invention, and illustrating certain details of the internal mechanism in elevation.

Figure 2 is a section taken on line 2 2 at Fig. 1..

Figure 3 is a section on the line 3-4 of Fig. 1. Figure 4 is a section on the line 4- 3- of Fig. l. Figure'5 is a section on the line 5--t'oi Fig. 1. Figure 6 is a group perspective view illustrating assembly details of an control means.

element of the air volume cal body of the burner.

Figure '7 is a top plan view of the burner, on a I reduced scale.

Figure 8 is a side elevation of the burner with the oil pump removed.

In the illustrated embodiment the burner coinc,

prises a main body portion 9 consisting of a substantially cylindrical hollow casting provided at its rear end with a pair of integral oppositely extending'lateralsupport arms disposed in a common horizontal plane the outer .ends of the in support arms being operatively engaged with elevation adjustment ,screws H in screw jacks i2 and which are operated in the usual manner by adjustment nuts i3. At the forward end of the able air propulsion means, such as a turbine blade fan generally designated as at it having a hub portion it rigidly connected with a rotatable shaft ii extending transversely through the fan housing and driven by suitable power means, comprising in this embodiment an electric motor iii suitably secured to the integral casting comprising the body portion 9 and the fan housing it. The fan housing M, at the side opposite to that on which the motor I8 is mounted, is provided with an air inlet hood 19 having a vertical open face or grill N that is permanently open to permlt of unobstructed air entry to the fan and so proportioned that the fan receives on its inlet side not less thanthe maximum volume of air which the fan is capable of moving. The face 40 2t) or an appropriate part of the hood it provides a mounting for a fuel oil pump 26 that is operatively connected with the shaft ll driven. from the motor is. It will be noted that with respect to the fan the motor l8 and the oil pump 25 are balanced at opposite sides of the fan hous= ing, the three units being axially aligned. The motor, the fan and'the oil pump are thus located in transverse axial alignment abovethe cylindri- 0 The fan housing has a vertical discharge 22 directly downwardly into the rear end of the cylindrical bodyportion 9, the housing being rear.- wardly extended somewhat beneath the fan by a web 23 to provide a plenum chamber 24 of uni- 5;,

form internal diameter from its rear end to a conical valve seat 25 formed in the forward end v of the chamber. As shown in Fig. 1 the conical seat 25 opens to a venturi 26 located forwardly thereof and between the seat 25 and the inner end of the venturi the wall of the body portion is formed with a cylindrical bore 21 to provide a restricted cylindrical throat through which air passes from the plenum chamber to the venturi or relief chamber 25. I

At its forward end the cylindrical body portion 3 has suitably secured thereto an axial extension consisting of an air blast tube or barrel 28 having a uniform internal diameter from end to end which is less than the internal diameter of the plenum chamberand which provides an axial continuation of the plenum chamber 2 8.

The barrel 23 is provided with, means for changing the direction of air flow through the barrel for the purpose of imparting a swirling motion to the air as it issues from the nozzle end of the barrel. In the illustrated embodiment this means consists of an air spiral comprising a hub 23 of a diameter less than the diameter of the barrel and carrying a series of spirally directed vanes or blades 30 which extend between the hub and the inner wall of the barrel, contacting the inner wall of the barrel through the entire extent of their outer edges. Slidable axially in close fitting engagement through the hub 23 is electrode mount 3| having an inwardly directed apex so constructed that no air may pass except through the spaces between the spirally directed blades 30. The air spiral is anchored in position within the barrel by means of attaching elements 32.

The barrel 28 in conjunction with the plenum chamber of the body 9 provides a cylindrical air discharge passage having a restricted throat 27 the bore of which is cylindrical and is coaxial with the cylindrical bore of the plenum chamber and the barrel. In its rear wall the body is provided with an assembly port covered by a detachable closure plate 33 formed with a central hub 34 which provides a bearing for an axially elongated sleeve member 35 coaxial with and rotatably mounted upon an oil discharge pipe or conduit 36 which extends axially throughout substantially the entire longitudinal extent of the air discharge passage of the burner. At the rear end of the burner the oil discharge pipe 36 extends through the detachable closure 33 and connects with a conduit 31 that leads to the oil pump. At the forward portion of the burner the oil pipe 36 is supported by the apex portion of the holder 3|, through which holder the pipe 35 passes in close fitting engagement. At'its forward end the oil pipe 36 is provided with a conventional discharge tip 31' through which the oil issues to be ignited by electrodes 38 and 39 mounted in bushings 40 and 4| passed. in sealed engagement through the conical holder 3| through countersunk sockets 42 and 43 provided therein for the purpose. The electrical leads for the electrodes are carried through bushings 44 in the wall of the barrel and the barrel isfurther provided with a port 45 closed by a detachable cover plate 46 through which access may be had to the electrical connections within the air passage.

Atits forward or nozzle end the barrel 28 is,

ulated at the outlet end of the plenum chamber, being controlled by valve means cooperable with the reduced throat 21 and seat 25 and adjustable axially of the discharge passage. In the disclosed embodiment such valve means comprises a hollow substantially obloid member 50 having a semi-spherical rear end portion 5|, a cylindrical central portion 52 the axialextent of which is equal to or greater than the axial extent of the cylindrical throat 21, and a conical front end portion 53, the three portions being integral and merging into one another.

An important feature of this invention resides in the fact that the maximum external diameter of the movable valve 50, as defined by its central cylindrical portion 52, is appreciably less than the internal diameter of the restricted cylindrical throat 21 whereby there is at all times a clearance between the valve and the throat so that the valve member may be shifted axially for movement entirely through the throat. The valve member 50 is mounted for sliding movement axially along the pipe 36, being restrained against rotation thereon by a gib 54 by which the valve and pipe are keyed together. A lateral tip 55 provides a stop means on the gib which defines the limit of forward axial movement of the valve. this limit being the maximum closing extent of the valve. The rear end or semi-spherical portion 5! of the valve member has a hub 56 for traveling threaded engagement over the externally threaded extent of the sleeve 35 so that as the sleeve 35 is rotated the valve is caused to move either forwardly or rearwardly depending upon the direction of rotation of the sleeve. This rotation of the sleeve is accomplished by means of a handle member 51 rigidly secured at the outer end of the sleeve where, it projects through the detachable closure plate 33. A bearing sleeve 58 rigidly attached to the operating sleeve 35 on the inner side of the hub 34 cooperates with the handle member 51 to restrain the operating sleeve against axial movement over the supporting pipe 36. The dotted line position of the valve 50 as shown in Fig. 1 indicates the position assumed by the valve in maximum open position. A detachable cap 59 secured on the rear face of the burner body protects the adjusting handle 51 against accidental manipulation and upon removing the cap 59 and detaching the closure 33 the valve assembly may be withdrawn axially through the assembly port, the diameter of the port being greater than the maximum diameter of the valve member.

As shown in Fig. 1, it will be noted that the plenum chamber and air discharge barrel are located in perpendicular relationship with respect tothe line of air flow as discharged through the fan outlet 2!. pressure within the plenum chamber becomes a static pressure so that the air flow is constant and unaffected by directional current ordinarily imparted where there is direct fan discharge.

In the operation of the burner there is no regulation or control of air on the inlet side of the fan; the fan inlet being unrestricted and therefore receiving the full rated capacity. The fan thus moves its full rated volume of air into the plenum chamber building up a static pressure therein and the air flow volume is controlled in the discharge passage by means of the valve asdescribed. Due to the clearance provided at all times between the cylindrical portion'52 of the valve and the cylindrical throat 21 of the air passage it will be evident that there will actuating member supported by said pipe and at all times, be a straight line airflow past and around the valve, securing uniform delivery to the same time against the wall of the barrel sothat when it issues through the nozzle annulus 41 it is traveling with a swirling motion which causes an expansion and dispersion by the action of centrifugal force. In order to relieve any vacuum creation at the area immediately adjacent the oil tip 31' the deflector 49 has been provided which insures that suflicient air will be passed directly around thetip to preclude the formation of avacuum.

Theventuri 26 providesan expansion chamber relieving air constriction immediately beyond the valve and this relief insures that the air flow will be directed along the periphery of the barrel 28'and not confined to its axial center.

.By dispersing the air flow to travel along the' peripheral inner surface of the discharge barrel there is obtained a greater freedom'for air flow as it is not obstructed by the electrodes and' nozzle adjacent the axial center of the discharge tube. i

Having described my invention what I claim is:

1. An oil burner having, in combination, fuel supply means, air supply means, an air blast tube connected to said air supply means, an oil discharge pipe extending axially through said tube and connected to the fuel supply means, said tube having a constricted throat, air control valve means carried bysaid pipe and movable axially thereon into and entirely through said throat, a valve actuating member carried by said pipe and movable thereon to operate said valve means, and means at the end of the oil discharge pipe for spraying oil-into the air leaving said air blast tube. 5

tube having a constricted throat, an air control valve carried by said pipe and 'movable axially thereon, said valve being of a size to pass entirely through said throat with a clearance therebetween in all positions of the valve, a valve movable thereon to operate said valve for adjust ment in and through said throat, said valve having a surface presented to the line of air flow of a shape to direct air passed. thereby to the periphery of the tube beyond the valve, and means at the end of the oil discharge pipe for spraying oil into the air leaving said air blast tube; I

3, An oil burner having, in combination, fuel supply means, air supply means, an air blast tube connectedto said air supply means and having a constricted throat including a cyilindrically bored passage, an oil discharge pipe extending axially through said tube and passage and connected to said fuel supply means, an air control valve carried by said pipe and movable thereon into and entirely through said throat passage,

a valve actuating member supported by said:

pipe and movable thereon to operate said valve .for adjustment in and through said throat passage, said valve having a substantially semispherical portion presented to the line of air flow,

a cylindrical portion extending therefrom, and a conically reduced portion therebeyond, the maximum diameter of saidvalve being appreciably less than the diameter of said cylindrical throat passage, and means at the end of the oil discharge pipe for spraying oil into the air leaving said air blast tube.

4. An oil burner having in combination, fuel supply means, air supply means, a hollow tubular air discharge member, a plenum chamber there- 'in in communication at one end with the air supply means, a constricted throat in the other end of said member, anair expansion chamber beyond said throat, an oil discharge pipe supported at one end in and extending through a wall of the plenum chamber axially through said throat and into the air expansion chamber, a fixed support in said air expansion chamber for the other end portion of said oil discharge pipe, means on said supportto direct air in a helical path along the wall of said expansion chamber prior to discharge therefrom, an air volume control valve movable axially on said oil discharge pipe into and through said throat, valve actuating means carried by said pipe'and movable thereon .to operate said valve, fuel atomizing means on said oil discharge pipe in the discharge end of said air expansion chamber, and means for igniting the atanized fuel.

THEOPHILUS H. SMOOT.