US2108918A

US2108918A - Liquid fuel burner

Info

Publication number: US2108918A
Application number: US101218A
Authority: US
Inventors: William F Falkenberg
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-09-17
Filing date: 1936-09-17
Publication date: 1938-02-22
Anticipated expiration: 1955-02-22

Description

Feb. 22, 1938. w. F. FALKENBERG LIQUID FUEL BURNER Filed Sept. 17. 1936 Patented Feb. 22, 1938 UNITED STATES PATENT OFFICE 2 Claims.

The invention relates generally to improvements in liquid fuel burners of the type shown and described in my co-pending application, Ser. No. 67,607, filed March 7, 1936, of which this ap- 5 plication is a continuation-in-part, and more particularly to that type of a burner wherein crude oil or the like is forcibly discharged into a novelly constructed rotatable fuel atomizlng nozzle so that the fuel is completely vaporized for free burning.

Some known types of liquid fuel burners having a rotating atomizlng nozzle cannot satisfactorily utilize the heavier known grades of crude oil because of their inability to effect thorough atomization of the oil and complete mixing of air with the hydrocarbons therein, with the result that inefficient firing is effected with great loss of potential heat. The unburned carbon tends to cling to the burner nozzle and to the walls of the fire box thus .necessitating frequent interruptions in service for cleaning.

Other known types of rotary liquid fuel burners can effect a more satisfactory mixing of the hydrocarbons and air only when the crude oil is pre-heated. However, these burners also are unsatisfactory also because they fail to produce a mixture for free burning. This is primarily because the air and fuel are not properly mixed in the burner to allow burning of the fuel at o the nozzle. It burns at the extreme end of the stream only after the improper mixture has been violently agitated. This agitation takes place only when the mixture strikes the back wall of the fire box or a baille therein. Obviously, the fuel is consumed as it rebounds from the wall or baille with the result that a back pressure is created in the flre box and pufllng" of the burner results. Accordingly either type of burner is expensive to operate, inefficient in results ob- .10 tained and in many instances wholly unsuited for certain specific installations. These and other known disadvantages in the use of known types of burners for burning the heavier grades of crude oil are all overcome satisfactorily, emciently and inexpensively by the construction disclosed herein.

It is therefore, an object of the invention to provide a liquid fuel burner with an improved rotatable fuel atomizing nozzle having a plu- ;,0 rality of circumferentially inclined passageways through which partly atomized fuel is entrained.

Another object is to provide a liquid fuel burner with means to effect complete mixing of air with the hydrocarbons and thereby deliver a free burning highly atomized fuel mixture at the discharge end of the burner.

Another object is to provide a fuel atomlzing nozzle with improved means to reduce liquid fuel to extremely ilne particles prior to its being entrained into the discharge end of said nozzle.

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Another object is to provide a fuel atomizing nozzle with means to prevent formation of a film of fuel on the inner surface of the receiving end of said nozzle.

Another obiect is to provide a rotatable fuel 5 atomizlng nozzle and shaft with novel means to efhciently reduce the liquid fuel to a highly atomized volatile substance and discharge said substance substantially uniformly.

Another object is to provide an improved fuel 10 atomizing nozzle which is positive in operation, inexpensive to construct and highly efficient.

The foregoing and such other objects of the invention as will appear hereinafter as the description proceeds will be more readily under- 15 stood from a perusal of the following specication, reference being had to the accompanying drawing, in which:

Fig. 1 is a vertical central sectional view, partly broken away, through a liquid fuel burner 20 embodying features of the invention, showing parts in elevation.

, Fig. 2 is an enlarged longitudinal sectional view through the improved fuel atomizing nozzle" showing associated parts in elevation. 25

Fig. 3 is an elevational view of the discharge end of the nozzle shown in Fig. 2.

Fig. 4 is a transverse sectional view taken on line 4-4 of Fig. 2.

Fig. 51s a view similar to Fig. 2, showing a 30 modied form of construction.

Fig. 6 is a sectional view of the fuel atomizing nozzle taken substantially on line 6-6 of Fig. 5.

As best shown in Fig. l, the liquid fuel burner preferably is of the type shown in my aforemen- 35 tioned co-pending application, and preferably includes a cylindrical casing ll having a dished end wall I2 which terminates in an annular flange I4 of reduced diameter. A substantially conical plate i5 is secured over the open face of 40 the cylindrical casing Il to provide a wall having a central opening I8 in axial alignment with the annular flange Il. An air nozzle I1, which tapers towards its free open end, is fitted over the ange I4 as shown, and is adapted to extend 45 into a similarly tapered flanged inlet opening I2 in a fire door cover plate Il on boiler 2|. The burner casing il may be held in an inclined position against the cover plate il in any practical manner but preferably is hingedly con- 50 nected thereto so that it may readily be moved into its operating position, as shown in Fig. 1, or swung outwardly clear of the opening I8. A hanged collar 22 preferably is tted over the enlarged end of the air nozzle i1 to close the 55 annular opening between said nozzle and the hanged opening II, if desired. y

A motor 23, mounted in axial alignment with the cylindrical casing il, has a driven shaft 24 extending toward said casing carrying an ex- 60 tension 25, the diameter of which preferably is successively reduced to provide a bearing portion 26, an extension 21 and a threaded end 23. 'I'he bearing portion 26 is journaled in a suitable bearing block 29, preferably mounted on the wall I3 of the casing as shown. Mounted within the casing II upon the large diameter of the shaft extension 25 is an air fan 3|, which may be of any type suitable for creating a uniform forced draft through the central opening I6 and out through the air nozzle I1. The direct flow of air through the casing II may be aided materially by providing a suitable dished baille 32 spaced from the wall I3 of the casing.

A fuel atomizing nozzle 33 is securely mounted upon the threaded end 28 of shaft extension 25 and extends into and preferably a short distance beyond the reduced open end of air nozzle I 1. As best shown in Figs. 2, 3 and 4, the fuel atomizing nozzle 33, which is in the form of a cylindrical body, preferably includes a fuel discharge cup portion having a uniform outside circumferential surface and an internal coned fuel discharge surface 34 which tapers outwardly circumferentially towards the free open end thereof. The relatively,

thick wall 35 of the cup portion is centrally apertured to receive the shaft end 28 and has a plurality of circumferentially spaced passageways 36 therein.

As best shown in Figs. 3 and 4, the passageways 36 are inclined circumferentially in a direction opposite to the direction of rotation of the fuel atomizing nozzle (as indicated by the arrows) for a purpose to be more fully described later.

An annular flange 31 extends from the wall 35 of said cup portion outwardly around but spaced from a portion of the shaft extension 21, to provide a fuel receiving chamber 38. Crude oil or other liquid fuel is delivered into the chamber 38 through a pipe line 39 which has its discharge outlet positioned directly above the embraced shaft 21 whereby all fuel discharged is deposited onto said rotating shaft. The embraced shaft portion 21 preferably is serrated longitudinally, as at 4I, or otherwise roughened to prevent the fuel from flowing down one side or the other thereof during its rotation. Obviously, the serrations 4| on the rotatable shaft cause the fuelA `receiving chamber 38 and are further broken up.

Some of the fuel, however, tends to adhere to said inner surface in the form of a fllm.

Formation of such a fllm of fuel is positively prevented by providing grooves 42 on the inner surface of the flange. The grooves 42 also are inclined circumferentially parallel with and one in axial alignment with each passageway 36. The fuel, instead of adhering to the inner surface of the flange is carried into the grooves 42 and entrained through the passageways 36 into the coned discharge portion of the cup and is discharged therefrom substantially radially into the path of air flowing through the annular passage 43 between the outside of the fuel atomizing nozzle 33 and the inside of the air nozzle I1.

It is apparent that the violent agitation and breaking up of the liquid fuel in the receivln air stream prior to and after it is discharged from the atomizing cup and effects complete mixing of the air and hydrocarbon to provide a highly volatile free burning substance which burns close to the nozzle.

In the fuel atomizing lnozzle shown in Figs. 5 and 6 and also shown in my said co-pending application, the air passageways 36 are spaced inwardly from the inner surface of the nozzle cup and also are inclined circumferentially in a direction opposed to the direction-of rotation of said nozzle. 'I'he rearwardly extending flange portion 31" however, has an internal annular flange 44 adjacent its free edgevand is inclined on its inner surface outwardly toward the bottom of the cup. Liquid fuel deposited therein through the fuel pipe line 39 is deposited, as before, upon the rotating serrated shaft portion 21 and is prevented from dripping or flowing over the edge of the receiving chamber by the internal annular flange 44. The free edge of the coned discharge chamber preferably is flared outwardly sharply, as at 45, and the internal edge portion of the air nozzle I1a is chamfered, as at 46, to insure wide radial distribution of the atomized liquid fuel. This form of discharge is particularly advantageous when the burner is installed in a. furnace having a relatively short fire box.

Although exemplary forms of the improved structures have been described herein in detail it is to be understood that the detail structure of thel liquid fuel atomizing nozzle and thetype of burner in which it is installed may vary to suit various manufacturing or installation requirements without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A liquid fuel burner including an air nozzle and a rotatable shaft extending therein, a fuel atomizing nozzle mounted axially within said air nozzle on said shaft, said fuel nozzle comprising a cup having an internal coned fuel discharge surface and an end wall, a flange extending outwardly from saidwall around but spaced from said shaft to provide a fuel receiving chamber, means feeding fuel to said receiving chamber, said wall having a plurality of inclined passageways extending therethrough, and the surrounded shaft portion and the inner surface of said flange each having serrations therein to reduce the fuel to flne particles prior to its being carried through said passageways into said cup.

2. A liquid fuel burner comprising, in combination with a blower casing and a rotary fan therein, an open ended discharge nozzle at the discharge end of said casing, a substantially tubular fuel atomizing nozzle mounted within said discharge nozzle for rotation with the fan, a

wallin said fuel nozzle dividing said nozzle into a fuel receiving chamber and a fuel discharge chamber and having a plurality ofcircumferen- 4 tially spaced angularly disposed parallel passage- WILLIAM F. FALKENBERG.