US2471025A - Oil burner - Google Patents

Description

Patented May 24, 1949 01L BURNER 'Biirje Konrad Danielsson, Abrahamsberg, and Lars Axel 'Widing, 'Goteborg,.Sweden, assignors to Aktiebolaget Gotaverken,JGoteborg, Sweden,

a corporation-of Sweden Application March 30, 1945, Serial No. 585,732 In Sweden March 14, 1944 Section 1, Public Law 690, August 8,1946 Patent expires March 14,- 1964 1 Claim.

The presentinvention refers to an arrangement. in oil burners of the type having a catching and collecting device provided in front of an atomizing nozzle for the fuel, Joy-means of which catching device :a controliable portion of the fuel jet is kept off the combustion zone outside the burner. In burners of this construction, the combustion air is generally-conveyed in a tube surrounding the atomizing 'IIQZZIGQJdd the catching device. In order under all operating conditions to ensure the best possible fuel economy, the fuel quantity and the air quantity may suitably be controlled in a definite relationship, so that the air quantity is reduced simultaneously as the injected fuel. quantity is reduced. At a low load, when the fuel and air quantities are small, the drawback is encountered, however, that the flame of the burner willbe"locatediimmediately adjacent to the nozzle on account of the small air velocity. I-t'may even occur that the flame will be located within the catching device, so that deposits will form in the latter, said clepositsbeing apt even to clog the passagesserving for carrying off the excess fuel.

The object of the invention is to eliminate this drawback and to provide .an oil burner inwhi-ch the combustion takes place well outside the catching device even at low loads.

According to the invention thisand other objects areattained by the provision, in combination with the feature that the combustion air conveyed through a space provided radially outside the atomizing nozzle and the collecting means is controllable as to the quantity thereof in relation to the quantity of fuel supplied to the combustion zone, of a guiding means adapted in a manner known per se to catch a portion of the air flowing forth through said space, said guiding means being so constructed that the air flowing therethrough will be directed obliquely inwardly toward the longitudinal axis of the nozzle and away from the fuel nozzle.

The invention will be described more closely hereinafter with reference to an example of embodiment as illustrated in the accompanying drawing.

Fig. 1 shows the outer portion of an oil burner in longitudinal section, and Fig. 2 shows a longitudinal section through a complete burner unit.

I designates a fuel nozzle having a variable spreading angle, if desired. Arranged about the fuel nozzle in a manner known per se is a rotary collecting drum 2. By displacing the nozzle l or by changing the spreading angle, the portion of the fuel discharged through the nozzle opening 3 may be varied, while the'quantityof fuel kept oi the combustion zone is collectedby the drum 2 andcarried off through the "opening 4 therein. "The combustion :airis conveyed in the space between the catching and collecting device fizand the wall- 5 ofthe burner'housing. Provided outside-the drum 2 is atubular collecting member 6 of a curved or dish-shaped configuration in sectionsaid member-serving as a collecting and discharging bowl for theoil carriedolf the drum 2. Outside the-member 8 there is-provided a tubular guiding member" 1 which is circular in cross section and which, together with the member- '5, eforms a guiding means for a certainportion' of the combusti'on air. The guiding means formedobyv the members '6 cand is preferably nozzle-shapedsin section, the same being thus restricted toward the outletopening 8. Preferably, the nozzle is directed obliquely outwardly toward the centre line or axis of the mouth of the nozzle.

: Arranged at the wall-'5 are obliquely positioned guide "blades 9, IB to :impart a rotary motion to themain body of the combustion air. The blades extendfrom the wall 5 inwardlyto about the radial position of the edge of the guide member 1 directedagainst the direction of flow 0f the air. In the illustrated example, a ring of guide blades Bis provided in .frontof theinlet opening of the guiding meanawhilea ring of guide blades Iii is provided behindsaid guiding means. .I'he blades 9.:and 18,: orthe latter :at least, preferably have asmall pitch, it: being furthermore of advantage to arrange them so that they will tog-ether cover the radially outer portion of the air space, entirely or in part, and overlap one another.

The oil collected in the member 6 is carried off through a tube II. This tube may advantageously be given an oblong cross-section, and may be obliquely positioned in a manner such as to aid toward imparting a turbulent motion to the combustion air flowing outside the same.

The front edge of the member 6 is separated by a gap [2 from the part carrying the collecting drum 2, so that air may pass through the space between the parts 2 and 6 to prevent the production of a vacuum in this space during the operation, whereby the flame might be drawn rearwardly.

When the contrivance is adjusted for injection of a comparatively small quantity of fuel, a relatively small quantity of combustion air being consequently supplied, the guide blade rings 9 and I0 will have a braking effect on the air. The guide member 1 catches a comparatively large quantity of air, and this air is conveyed at an increased velocity through the outwardly restricted nozzle directly toward the axis but at the same time obliquely outwardly from the nozzle opening 3. The ejected oil jet will thus have the necessary quantity of air supplied thereto at such a velocity and in such direction that the flame cannot strike into the burner. The guiding means also involves the advantage that the collecting member 16 is cooled by air, in operation.

Fig. 2 shows a complete burner unit provided with a burner according to Fig. 1. As will be seen from the figure, the nozzle I is arranged at the one end of a hollow, axially displaceable tubular member H. The tubular member may be displaced to and fro with the aid of a hand lever I2 and levers I3, i4 and I5, among which the 1evers I4 and I5 are mounted on a pin I 6, besides which the lever I5 is provided with a rounded end portion engaging into an annular slot I"! at the end of the member I I.

Liquid fuel is supplied to the nozzle I through the tubular member II by means of a pump arranged in a housing I8. The nozzle I is located in the interior of the rotatable drum 2 forming the catching device for a portion of the jet cone from the nozzle. The drum 2 is arranged on a hollow shaft I9 surrounding the member I l, and is rotatable relatively to the latter and mounted in a guide disk 20 within the casing 2| and in the rear wall 22 of the casing 2|. Arranged 0n the casing 2| is an electric motor 23 adapted by means of wedge-shaped belts 24 to drive the hollow shaft I9, to which the fuel pump is coupled. Furthermore, the shaft I9 has a fan wheel 25 secured thereto and adapted to suck combustion air through openings 26 in the rear cylindrical portion of the casing 2I and to press such air into the furnace. Arranged in the cylindrical portion of the casing ZI is a controlling slide valve 27 for the combustion air. This slide valve, which is constituted by a body of revolution and situated coaxially with the fan wheel in front of the inlet thereof, may be adjusted axially by a rod 28 with the aid of a lever 29 operated by means of the hand lever I2. The openings 26 are tapering at the ends 30 thereof directed toward the fan wheel, so that theslide valve 21, when displaced to the right in Fig, 2 from the position shown, will initially reduce the air intake area comparatively slowly and then relatively more rapidly at the end of its displacement in said direction. By

shaping the openings 26 in a suitable manner and by a suitable association of the fuel control and the air control, it will be found possible to obtain an appropriate relationship between the air quantity and the fuel quantity at different loads.

What we claim is:

In an oil burner, a conduit for combustion air, a nozzle in said conduit for ejecting a spray of fuel oil, a tubular member surrounding said nozzle and spaced therefrom for catching and collecting part of the oil discharged from the nozzle, a hollow guide member outwardly and radially spaced from the tubular member and co-acting therewith to form a passage having an outlet portion extending obliquely toward the longitudinal axis of the nozzle, said passage receiving a minor part of the combustion air in said conduit and. having a cross sectional area decreasing toward its outlet, the outer wall of said guide member and the inner wall of said conduit forming a second air passage through which a major part of the combustion air passes, and spaced slanting guide blades connected to the inner wall of said conduit and extending into said second passage to impart rotary motion to the combustion air passing therethrough.

BoRJE KONRAD DANIELSSON. LARS AXEL WIDING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,784,747 Peckelhoif Dec. 9, 1930 2,005,832 Vidale June 25, 1935 2,202,822 Behrens June 4, 1940 2,247,768 I-Iuwyler July 1, 1941 2,256,080 Eweryd et a1 Sept. 16, 1941 2,374,290 Johansson Apr. 24, 1945 FOREIGN PATENTS Number Country Date 435,679 Great Britain Sept. 25, 1935 460,964 Great Britain open to inspection Feb. 3, 1936 648,409 Germany July 30, 1937 771,692 France July 30, 1934

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