Title:
ROTARY-TYPE OIL BURNER
United States Patent 3623664


Abstract:
An oil burner wherein a liquid fuel film is formed on a rotary plate having a plurality of toothed profiles along the circumference thereof, and air is made to pass along the rotary passage which is encircled by the toothed profiles of said rotary plate and a burner ring (or a burner tile) installed at a position close to the outer side of said rotary plate, so that liquid fuel may be made into fine particles by means of said air coming into contact with the liquid fuel film at the edge of the toothed profiles and at the same time groups of fine fuel particles may be uniformly mixed in said air.



Inventors:
TSUJI SHOICHI
Application Number:
05/006996
Publication Date:
11/30/1971
Filing Date:
01/30/1970
Assignee:
ISHIKAWAJIMA-HARIMA JUKOGYO KK.
Primary Class:
Other Classes:
239/224
International Classes:
F23D11/06; F23D11/04; (IPC1-7): B05B3/02
Field of Search:
239/214,214
View Patent Images:
US Patent References:
3508852OIL BURNER1970-04-28Hourwitz et al.
2560866Rotating atomizing cup burner1951-07-17Hoogendam
1674631Oil burner1928-06-26Benniger
1627690Centrifugal fluid-fuel burner1927-05-10Denison
1506226Centrifugal atomizer1924-08-26Dick
1029818N/A1912-06-18Noble
0540864N/A1895-06-11
0397775N/A1889-02-12



Foreign References:
NL76549A
CH325444A1957-11-15
Primary Examiner:
Wood Jr., Henson M.
Assistant Examiner:
Grant, Edwin D.
Claims:
What is claimed is

1. A rotary-type oil burner comprising a substantially flat rotary plate having a plurality of teeth formed along the outer edge thereof, burner ring means coaxially surrounding said plate whereby a plurality of passages are formed between said ring means and the teeth on the edge of said plate, means for rotating said plate whereby said passages rotate about the axis of said plate, means for applying fuel oil centrally to one side of said plate whereby a substantially uniform thin film of oil flows radially outwardly on said one side of said plate upon rotation of said plate, and means for passing air through said passages, whereby said air contacts said oil film and said edges of said plate and said oil is thereby atomized and mixed with said air.

2. A rotary-type oil burner comprising a substantially flat rotary plate, burner ring means coaxially surrounding said plate, said plate having a plurality of teeth formed around its periphery whereby a plurality of passages are formed between said teeth and said ring means, means for rotating said plate whereby said passages rotate about the axis of said plate, means for directing a flow of fuel oil centrally on one side of said plate whereby a substantially uniform thin film of oil flows radially outwardly on said one side upon rotation of said plate, and means for passing a substantially uniform flow of air through said passages from said one side of said plate, whereby said air contacts said oil film at said teeth and the oil is thereby atomized and mixed with the air.

3. The oil burner of claim 2 wherein said means for passing air through said passages comprises an air chamber connected to said ring means and surrounding said one side of said plate.

4. The oil burner of claim 3 wherein said means for rotating said plate comprises a rotary shaft extending through said air chamber and connected centrally to said one side of said plate, and means external of said chamber for rotating said shaft.

5. The oil burner of claim 4 in which said shaft is hollow, and said means for directing a flow of fuel oil on said plate comprises aperture means in said shaft for feeding oil to the hollow center of said shaft, and aperture means in the end of the shaft adjacent said plate whereby said oil is directed from the hollow center of said shaft onto said plate.

6. The oil burner of claim 5 wherein the profile of the teeth of said plate are defined by the expression:

Description:
DETAILED EXPLANATION OF THE INVENTION

The present invention relates to generally an oil burner and more particularly a rotary-type oil burner.

In order to burn the heavy liquid fuels, they are generally atomized into finely divided particles with a particle size ranging from tens to hundreds microns and mixed with the air. For this purpose, the mechanical atomizers or pressure atomizers, auxiliary-fluid atomizers and rotary-cup atomizers are generally used. All of these atomizers are designed without any special attention to the fact that the atomized liquid fuels may be uniformly mixed with the air. In the conventional liquid fuel burners, the air is swirled or made to flow at high speed for the better mixing with the atomized fuels, but they are not sufficient. It is very important to mix the atomized liquid fuels with the air in order to attain the complete combustion of the liquid fuels. It is a well-known fact that the more uniformly the air and the atomized liquid fuels are mixed with each other, the more complete the combustion with less smoke and soot and with less excess air.

Accordingly, the primary object of the present invention is to provide a rotary-type oil burner which can atomize the liquid fuels into uniform particle sizes and mix uniformly with the air.

In brief, the present invention provides a rotary-type oil burner characterized in that a rotary plate having a plurality of teeth formed along the outer periphery thereof is rotatably disposed longitudinally of a burner ring or the like in such a manner that a plurality of rotary passages may be defined between the inner surface of said oil burner ring or the like and each of the teeth profiles; a fuel oil supply pipe is provided for supplying fuel oil in such a manner that said fuel oil may be expanded over said rotary plate in the form of a thin film; and air supply pipe is provided for passing the air through said passages at high speed; whereby said air passing through said passages at high speed can contact with said thin film of said fuel oil along the tooth profile edge of said rotary plate.

By a rotary-type oil burner in accordance with the present invention, the liquid fuel may be atomized and uniformly mixed with the air. The uniform mixing of the atomized fuel oil with the air can be further ensured by suitably selecting the profile of the teeth of the rotary plate. The rotary-type oil burner in accordance with the present invention is simple in construction and inexpensive to manufacture.

The above and other objects, features and advantages of the present invention will become more apparent from the following description of one illustrative embodiment thereof with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view of one embodiment of a rotary type oil burner in accordance with the present invention;

FIG. 2 is a front view thereof only illustrating the center portion for explanation of the atomization of fuel oil and the mixing with the air; and

FIG. 3 is a fragmentary plan view of a rotary plate thereof for explanation of obtaining the tooth profile for uniform mixing.

A burner ring 6 having a suitable diameter is extended from the front wall of a wind box 4 to which is connected one end of a duct 5 whose the other end is coupled to a blower (not shown). The wind box 4 is disposed at the entrance or inlet of a primary combustion chamber 8 which is encircled with a burner tile 7 in such a manner that the burner ring 6 is placed upon the burner tile 7. A hollow rotary shaft 2 is extended along the longitudinal axis of the wind box 4 and has a plurality of equiangularly spaced-apart fuel-ejecting holes 10 formed along a circle upon the outer peripheral surface of the front portion of the rotary shaft 2 and a plurality of equiangularly spaced-apart fuel inlets 11 formed in the similar manner as the ejection holes 10, at the rear portion of the rotary shaft 2. The rotary shaft 2 is journalled by a bearing 3 which in turn is supported by the burner ring 6 through ribs 9 and a bearing 3' which in turn is securely fixed to the wind box 4. The fuel inlets 11 are communicated with a fuel supply pipe 12 extending from a fuel oil pump (not shown) through a sealing member 13 which sealingly surrounds the fuel oil inlets 11. A pulley 14 is carried at the rear end of the rotary shaft 2 and at the front end thereof is rotatably fixed a rotary plate 1 having a plurality of teeth. Thus, the rotary flow paths 18 are defined between the edges of the teeth of the rotary plate 1 and the inner surface of the burner ring 6. A motor 16 drives a belt wrapped over the pulley 14 of the rotary shaft 2 and a pulley 15 carried by the motor shaft so that the hollow rotary shaft 2 and the rotary plate 1 are rotated. Consequently, the fuel oil flowing through the rotary shaft 2 is ejected through the ejection holes 10 into a thin film 19 extending over the inner surface of the rotary plate 1. Upon rotation of the rotary shaft 2 and the rotary plate 1, the fuel oil is forced into the hollow rotary shaft 2 from the fuel oil supply pipe 12 by the fuel oil pump through the sealing member 13 and the inlets 11. The fuel oil is ejected from the ejection holes 10 which are so formed as to contact with the rotary plate 1. Since the ejection holes 10 are angularly formed so that the fuel oil ejected from the holes 10 is made in contact with the rotary plate 1, the ejected fuel oil is extended over the inner surface of the rotary plate 1 as thin film 19 by the frictional force and the centrifugal force, and finally reaches the edge 17 of the rotary plate 1. When the fuel oil film formed upon the rotary plate 1 is exceedingly thin, the direction of the flow of the thin film is radial before it reaches the edge of the rotary plate 1.

The air is supplied into the wind box 4 through the duct 5 from the blower (not shown). The compressed air is ejected through the paths 18 defined by the inner surface of the burner ring 6 and the edge 17 of the rotary plate 1, into the primary combustion chamber 8. The thin fuel oil film at the edge of the rotary plate 1 contacts with the high speed air flow continuously directed toward the primary combustion chamber 8 through the rotary paths 18 so that the fuel oil thin film 19 is separated from the rotary plate 1 and is atomized into finely divided particles which are continuously mixed with the air.

By suitable selection of the profile of the tooth of the rotary plate, the atomized fuel oil particles may be easily mixed with the air flow.

Referring to FIG. 3, the profile of the tooth of the rotary plate 1 for uniform mixing will be analyzed when the air flow velocity through the rotary paths 18 is uniform. The maximum radius of the rotary plate 1 is designated by r2 ; the root radius, by r1 ; the distance between the center of the rotary plate 1 and the point P at the flank by r; the center of the rotary plate 1, O; the angle between OA and OP, by θ; a small increment of the angle θ, by dθ; the angle between OA and OB, by θ2 ; and an increment along the circle with the radius r 1 corresponding to the angle increment dθ, by ds 1. The thin fuel oil film flowing in the radial direction in the angle dθ reaches the edge PQ after passing through ds 1. The thin fuel oil film which has reached the edge PQ is separated from the rotary plate 1 and then atomized and mixed with the air flow passing through a small area PQST (area=dF) in the rotary path. When the velocity distribution of the air flow is uniform, the equation (I) must be satisfied in order that the atomized particles are uniformly mixed in the air flow.

dF/ds 1 =constant (I)

Since

dF=rθ. dr and

ds 1 =r 1 dθ,

substituting them in equation (I) and integrating, with the boundary conditions of θ=θ2 and r=r 2, we obtain

r 2 =r 2 - cr 1 log θ2 /θ (II)

The equation (II) shows the curve of the profile of the tooth of the rotary plate 1. C is a constant which is determined when the area of the air flow path is given.

In the above embodiment, the rotary paths 18 have been described as being defined between the edge of the rotary plate 1 and the burner ring 6, but it will be understood that the rotary paths may be defined between the edge 17 of the rotary plate 1 and the burner tile 7 without the use of the rotary plate 6. It will be understood that other variations and modifications can be effected without departing the true spirit of the present invention as described hereinabove and as defined in the appended claims.