US2202981A - Oil burner - Google Patents

Description

W. O. BEHRENS UIL BURNERv June 4, 194C.

Filed July ll, 1936 Zzdezzfor /L/Zz'a/zz 0. Be/areas y; ya@

v Patented `lune 4, 1940 UNITED STATES PATENT OFFICE OIL BURNER William O. Behrens, Harvey, Ill.

Application July 11, 1936, Serial No. 90,232

6 Claims;

The present invention relates to improvements in oil burners.

' air is supplied byl forced draft, and more speciiically in which primary air is supplied by a high pressure fan, and in which a low pressure fan supplies secondary air and also the air for the high pressure fan.

A further object is to providetwo fans discharging in series and parallel, and driven jointly.

'from a common source, the first fan having a' relatively large capacity and a low pressure output, and the second fan having a relatively small capacity and high pressure output.

Other objects of the invention are to provideI a novel oil burner which is eiiicient in operation,v

which effects a thorough mixing of air and fuel, and in which the low pressure air is controlled with the fuel supply, so that the fire is never lazy and smoky and the eiiiciency does not vary with the draft.

Further objects and advantages will become apparent as the description/proceeds.

In the accompanying drawing, Figure 1 is a longitudinal sectional view of an oil burner embodying the'features of my invention.

Figs. 2 and 3 are transverse sectional views taken respectively along lines 2-2 and 3,-3v

stream of air and finely atomized fuel oil into a furnace. In the present instance, a fragment of the furnace is illustrated, the furnace having air fan or blower 2l.

a refractory wall 4 formed with a burner opening 5. A burner front plate B is secured against the exterior of the wall 4, and has an opening I in registration with the opening 5.

vThe burner has a low pressure air nozzle 8 extending into the opening 5. Preferably, the

lnozzle 8 is in the shape of a Venturi tube. The

peripheral wall of the opening 5 is shaped to conform to the nozzle 8. An outer peripheral flange 9 on the inlet end of the nozzle 8 is securely bolted to the plate 6.

The nozzle 8 opens from a housing Ill enclos- 4ing a low pressure air fan or blower II, and having a cover I2. 'Ihe housing is suitably supported, with thel coverv I2 in position against the flange 9. The cover I2 is formed with a flange I3 tapered internally to provide a continu ation of the nozzle 8, and the portion thereof circumscribed bythe flange I3 constitutes a radially disposed plate member III terminating in a concentric inner ring I5. A rotary damper or shutter member I6 is disposed against the member y I `4, and is adjustable by means of a rod II pivotally connected to one side, as illustrated in Fig. 2,

and extending out of the housing I0. Themembers I4 and I6 have peripheral spaced openings I4a and Ilia movable into various degrees of registration to regulate the amount of air discharging through the nozzle 8.'

Extending coaxially through the nozzle 8 is a high pressure air nozzle I8. This nozzle is tapered so that the intervening annular air space between the nozzles is of gradually increasing flow area. The nozzle I 8 is mounted on the end of a' tube I9 which extends through and is supported in the ring I5, and which constitutes the axial outlet of a housing 20 enclosing a high pressure The tube I9 also supports the damper member I6.

The blower 2| may be of any suitable form, and in the present instance has an axial inlet taking low pressure air through an axial opening 22 in the housing 29 from the housing I0, and has a peripheral discharge. A circular balile or guide plate 23 is mounted substantially in the center I of the housing 20, and serves to direct air from the periphery inwardly to the tube I9.` Likewise, the low pressure blower II., although smaller in diameter than the blower 2|, has an axial inlet and a. peripheral discharge into the housing I Il. A baffle or guide plate 24 is disposed between the blowers II and 2l to direct air from the housing I0 to the inlet opening 22 of the housing 20.

Secured to and closing one side of the housing IIJ is a cylindrical housing 25 having a plurality of air inlets 25, 21 and 28 opening from the atmosphere. The inner end wall of the housing 25 is formed with an axial outlet opening 29 which communicates with the housing I0, and

which is in direct registration and closely interfitting relation with the inlet of the blower I I.

The two blowers I I and 2l are mounted ooaxially on a common drive shaft B which is journalled in spaced bearings 3i and 32 in opposed walls of a gear chamber 33 Within the housing 25. The outer end of the shaft 38 is also supported in a sleeve 3G on a valve body 35 mounted on the outer end of the housing 25. able means may be provided for driving the shaft 30, and in the present instance this means comprises an electric motor 36 having a casing 3l built into the outer end of the housing 25 between the gear chamber 33 and the valve body 35.

Mounted for rotation Coaxially Within the high pressure air nozzle I8 and coacting therewith to define a tapered annular air passage is a substantially cylindrical atomizing cup 38 which is fixed on the inner end of the shaft 3U, and the interior of which is flared toward and open at the outer end. Extending longitudinally through the shaft 30, which is hollow for this purpose, is an elongated fuel supply tube 39. A nozzle 40 is mounted on the outlet end of the tube 39 within the atomizer cup 38. The other end of the tube 39 is fixed in the valve body 35, and in communication with a passage @I 'adapted to be connected by a throttle valve I2 to a tube i3 leading from a pump (not shown). The pump has a drive shaft 44 which extends transversely of the shaft 30 into the gear chamber 33 for a drive connection with the motor 36. In the present instance, the shafts are connected by a worm l5 and worm wheel 45, and the latter dips into a lubricant in the bottom of the chamber 33. The air shutter I6 and the fuel valve L32 are interconnected for joint operation from a single actuator 32a which may be operated manually. To this end, the rod ll is pivotally connected to one arm of a bellcrank lever 41 pivoted on the housing i0. 'I'he other arm of the lever 41 is connected by a rod I8 to a crank arm 159 on the plug of the valve 42. A turnbuckle 50 is interposed in the rod i8 and affords means for adjusting the ratio of low pressure air to fuel. To insure an intimate fuel mixture and ne atomization of the fuel, two sets of peripherally spaced helical vanes 5I and 52 are disposed respectively in the annular low pressure and high pressure air discharge passages. These sets of vanes are oppositely inclined and rigid respectively with the nozzles 8 and i8. Nozzles with vanes of different inclination may be substituted depending on the nature of the flame desired. Thus, the flame may be long and narrow or short and wide. The vanes are so orientated that, assuming the cup 38 as rotating clockwise, the high pressure primary air is discharged counterclockwise, and the low pressure secondary air is discharged clockwise.

The oil burner with the speciiic features of the nozzle structure herein disclosed, but indef pendent of the air and fuel regulating means and of details of the air supply means, is claimed in my copending application Serial No. 150,279, filed June 25, 1937.

In operation, air enters the housing 25 through the openings 26, 2I and 28, cools the motor 36, and passes to the blower I I. It is discharged into the housing IU, and passes from there in part to the nozzle 8 and in part to the blower 2l. The

Any suitair from the blower 2l passes to the nozzle I8. Fuel is supplied through the valve '32 and the tube 39 to the nozzle dll from which it is discharged into the revolving atomizing cup 33. The fuel and air are intimately mixed. When the flame is turned down, the shutter I3 is adjusted to reduce the volume of low pressure secondary air, but the full supply of primary air is maintained. As a result, the flame is never lazy or smoky, and a high efficiency is always maintained.

I claim as my invention:

1. In an oil burner, in combination, a secondary air nozzle, a secondary` air housing in cornmunication with said nozzle, a primary air nozzle coaxially associated with said secondary air nozzle, a high pressure low capacity blower in said housing for discharging air to said primary air nozzle and having an inlet open to the interior of said housing, a fuel nozzle extending into said primary air nozzle, a low pressure high capacity blower mounted in and discharging air to said housing and having an atmospheric air inlet, said rst mentioned blower having relatively long and narrow blades,- with a relatively large external circle of revolution and said second mentioned blower having relatively short and broad blades with a relatively small external circle of revolution, and a drive shaft for said blowers extending axially of said nozzles.

2. An oil burner comprising, in combination, associated primary and secondary air nozzles, a fuel nozzle associated with said primary air nozzle, a high pressure blower for supplying air to said primary air nozzle, a low pressure blower for supplying air to said high pressure blower and to said secondary air nozzle, means for supplying fuel to said fuel nozzle, means for regulating the fuel supply, means for regulating the supply of secondary air from said low pressure blower to said secondary air nozzle, and manually operable means interconnecting the fuel supply regulating means and the secondary air supply regulating means for joint operation, whereby an increase in the fuel supplied will be accompanied by a corresponding' increase in the supply of secondary air.

3. In an oil burner, in combination, an external secondary air housing having an atmospheric air inlet in one side and an aligned secondary air outlet in the other side, a secondary air nozzle connected to said housing and communicating with said outlet, an internal air housing rigidly mounted within said external housing and in spaced relation thereto and having an air inlet in one side opening from said external housing and an aligned primary air outlet in the other side, a primary air nozzle mounted in said eX- ternal housing and communicating with said primary air outlet and extending in concentrically spaced relation through said secondary nozzle, a ldrive shaft extending coaxially through said housings, a rotary propeller having a closed end disk fixed on said shaft in axially spaced relation to said internal housing and having a plurality of short wide vanes with a relatively small external circle of revolution in annularly spaced relation on the side of said disk remote from said internal housing, the inner ends of said vanes extending partially across said firstr mentioned inlet, air from the periphery of said propeller being directed by said external housing about said internal housing to said first mentioned outlet. means for directing air from the periphery of said propeller radially inwardly to said second mentioned inlet, a second propeller having a closed end disk fixed on said shaft within said internal housing and having a plurality of annularly arranged narrow long vanes of a relatively large external circle of revolution on one side of said last mentioned disk, the inner ends of said last mentioned vanes extending partially across said second mentioned inlet, air from the periphery of said second mentioned propeller being directed by said internal housing radially inwardly to said second mentioned outlet, means for supplying fuel oil axially through said shaft and including a fuel nozzle for discharging fuel throughsaid `primary air nozzle, and means for rotating said shaft.

'4. An oil burner comprising, in combination, primary and secondary air nozzles, a fuel nozzle extending into said primary air nozzle, means for supplying high pressure air to said primary nozzle and low pressure air to said secondary air nozzle, means for supplying fuel oil to said fuel' nozzle, means for regulating the fuel supply, means for regulating the volume of air supplied to said secndary air nozzle, and means interconnecting said last two 'mentioned means for joint synchronous operation, whereby an increase in the fuel supplied will be accompanied by a proportional increase in the supply of secondary air. y

5. An oil burner comprising, in combination, primary'and secondary air nozzles, a fuel nozzle extending into said primary air nozzle, means for supplying high pressure air to said primary air nozzle and low pressure air to said secondary air nozzle, means for supplying fuel oil to said fuel nozzle, means forregulating the fuel supply, means for regulating the volume of secondary air, and means interconnecting said last two mentioned means for joint synchronous operation, whereby an increase in the fuel supplied will be accompanied by a proportional increase in the supply of secondary air.

6. An oil burner comprising, in combination, primary and secondary air nozzles concentrically mounted to discharge coaxially into a furnace, a fuel nozzle extending into said primary air nozzle, means including a quantity regulating means for supplying fuel oil to said fuelnozzle, a high pressure blower for supplying air to said primary nozzle, a low pressure blower for supplying air to said secondary air nozzle, a damper interposed between said low pressure blower and said secondary air` nozzle for controlling the supply of air to said secondary air nozzle, and means interconnecting said regulating means and said damper, said last mentioned means being manipulable for joint operation of said regulating means and said damper and being adjustable as lto its length to vary the ratio of secondary air t vfuel oil.

WILLIAM O. BEHRENS.

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