US1747798A

US1747798A - Fuel burner

Info

Publication number: US1747798A
Application number: US82337A
Authority: US
Inventors: Scrimgeour William
Original assignee: Individual
Current assignee: Individual
Priority date: 1926-01-19
Filing date: 1926-01-19
Publication date: 1930-02-18
Anticipated expiration: 1947-02-18

Description

Feb. 18, 1930.

W. SCRIMGEOUR FUEL BURNER Filed dan. 19, 192s 2 Sheets-Sheet Feb. 18, 1930. w. scRxMGEoUR 1,747,798

FUEL BURNER Filed Jan. 19, 1926 2 Sheets-Sheet 2 .y futon-ego 'Patented Feb. 1.8, 1930 soRmGEoUR, Ko1? WASHINGTQN, DISTRICT or' COLUMBIA roar. BURNER Application legiil'anuaxy 19, 1926. Serial No. 82,337.

' This invention relates to fuel burners and.

particularly to a burner for the combustion of heavy or non-'volatile fuel such as kerosene distillates and @fuel oils.

5 In burning non-volatile oil by heating the l same to Aform a gas and then causing the gas to entrain the air necessary for combustion,

asin a Bunsen burner, the operation is characterized by a roaring which is very objectionable in any installation andv particularly in burners for domestic use.. It has been proposed to mechanically atomize non-'volatile fuel by or into a stream of low pressure air ,but burners of this type are open to the objection that the vaporization ofthe fuel is not complete and carbon deposits accumulate in the burner.

In accordance with the present invention efiicient and substantially noiseless combustion of non-volatile fuel is obtained by injecting a spray of liquid fuel under. high pressure into a quantity of air insuilicient for complete combustion, burning a small portion of the fuel to provide heat for the vaporization of the remaining part,.then passing the vaporized fuel mixture into a body of air suilicient to support complete combustion. The quant-ity of heat furnished by the partial burning of the rich mixtureV may be suiiicient to transform the fuel into a permanent gas or it may be suiiicient only to vafporize the fuel. In any event, the liquid uel is made available for combustion by heating the same with a limited quantityof air, and

l not solely by mechanical'atomization.`

An object of the invention is to provide an improved method and apparatus for effecting the quiet and eiiicient combustion of liquid fuel which is non-volatile at atmospheric temperatures. VAn object i is to provide al method of burning non-volatile fuel by which a rich fuel mixturey is .partially burned to provide heat for thevaporization of the bulk of the fuel. An object is to provide a method of burning fuel in which a rich and burning fuel mixture is caused to travel in a spiral path in one plane and from which path the vaporized mixture is withdrawn in a direction normal to the plane of the path for mixture with a larger quantity of combustion supporting air; The invention has for other objects the provision of apparatus capableof carrying out the novel method of combustion and particularly apparatus having a Vaporizing chamber in which a'rich fuel mixtureis de- 55 livered for partial combustion and from which the vaporized mixture passes into engagement with additional air andis completely burned. -A further object ofthe invention is to provide a vaporizing chamber of spiral shape from which the vaporized mixture passes in a direction normal to the plane ofthe spiral. l More specifically, an object is to provide va burner having side walls which define a spirally-'shaped vaporizing 65' chamber. into which a rich fuel mixture is introduced for partial combustion, a top wall-KA provided with an outlet opening or openings adjacent the axis o f thespiral and with a passage for delivering additional air to the burn` 7 ing mixture as it escapes from the vaporizing chamber. These and other objects of the invention which will be apparent from the following description may be attained by the embodiment of my invention which is illustrated in the accompanying drawings in which,

Fig. 1 is a plan view of the burner and a portion of the air supplying conduit;

Figs. 2,- 3 and 4 are vertical sectionsthrough the burner as taken on the respective section lines 2 2, 33, and 4 4, of Fig. 1;

Fig. 5 is a horizontal section through the burner on line 5-5 of Fig. 4; and

Fig. 6 is a fragmentary vertical section illustrating a modified form of air directing l nozzle. C. f

In the drawings, the reference character A indicates the burner head generally, the character B the air supply conduit and the character C indicates the fuel pipe. The burner head comprises a bottom `Wall 10, a top wall 11 of annular shape and a false bottom wall 12 of spiral shape'. The top and bottom walls are joined by an outer wall 13, and the top wall 11 and the falseubottom wall 12 are 95 joined by an inner cylindrical wall lll'which cooperates with the walls 11, 12'and 13 to form a spirally-shaped vaporizing chamber 15. The outer side wall 1 3 is approximately cir?" cular in section butis incomplete to provide 10 a tangentially arranged opening 16 for the introduction of the fuel and air. As best shown in Fig. 5, the opening 16 is, arranged for the introduction of the fuel at the widest i part of the spiral chamber defined by the ecing chamber 15. The nozzle 19 and outlet- 20 are so constructed that the high pressure oil enters the chamber in the form of a fine spray or mist. The air directing nozzle 18 is provided with a passage or passages 21 for introducing a limited quantity of air into the chamber 15 and around the spray of liquid fuel. The nozzle proper of the air direct- A ing device 18 is provided by a short cylindrical wall 22 which directs the air flowing through the openings 21 into the chamber 15 in a tangential direction.

The air and fuel inlet nozzle 18 lies in line with or to the rear of the adjacent portion 13of the outer wall 13.of the spiral vaporizing chamber. This arrangement results in a relatively long line of travel from the oil.

nozzle to the portion of the wall 13 which eX- tends transversely of the axis of the fuel nozzle, and it preventsthe residual portion of the fuel stream which re-en-ters the wide portion of the spiral path from sweeping across the-fuel nozzle and spark gap. Air passages 23 in the plate 17 permit the introduction of an additional quantity of primary air.

The rear face of the nozzle 18 is provided with a yoke 24 for receiving a spark plug S,-

which spark plug is retained 'in operative position by a set screw l25.l The spark gap 26 of the spark plug is arranged inline with and close to the fuel outlet 20 of the nozzle 19.

The top 11 is preferably bent upwardly around the inner wall 14 and is provided with an opening or openings 27 for permitting "the passage of the fuel mixture from the vaporizing chamber. As illustrated, a plurality of 1 annularly arranged openings 27 are provided, which openings are symmetrically disposed with respect to the inner wall 14, that is, withA respect to gtheaxis of the spiral vaporizing chamber 15.l

The supply of secondary air in quantity sufficient to complete the combustion of the fuel is passedinto the air chamber 28Vformed between the bottom 10 and the false 'bottom- 12 through' an opening 29 ien the plate 17. A stud 30 which is arranged axially of the spiral vaporizing chamber 15 and the inner wall 14 is secured to the bottom wall 10 and carries a deflector 31 at its upper end. The lower face 32 of the deflector 31 has the form of an upwardly flared cone, except at the central portion thereof, which is provided with a downwardly directed flange 33. The deflector 31 is threaded upon and therefore,

adjustable along the stud 30 to permit the regulation of the quantity of secondary air which is delivered to the burner. The quantity of air may also be regulated, if desired, by turning the wall 14, which is threaded in the false bottom 12, to adjust the position of the top of the wall'14 with respect to the level of the top wall 11.

The false bottom 12 slopes toward a drain opening' 34 which communicates with the drain pipe 35 for permitting the escape of any unvaporized fuel which might accumulate in the vaporizing chamber if the fuel fails to ignite.

As shown in Fig. 6, the air nozzle 18 may be provided with forwardly converging walls 22 for increasing the velocity at which the gir is introduced into the vaporizingcham- The operation of theburner is as follows :g

y pressure from suitable sources, such as an oil pump and a centrifugal blower, respectively. As the burner does not depend upon the velocity of the air `stream for the vaporization of thefuel, the airis supplied through conduit B at a relatively low pressure. The pressure in .the-fuel supply pipe C is relatively high, however, as the fuel is to be projected into the `vaporizing chamber as a fine spray.

-To place the burner in operation the fuell pump and blower are started and the ignition l,circuit is closed through'the spark plugS.

The spark gap '26 ignites the fuel but the -quantity of air supplied through the openings 21 is sucli that the point of vignition of the fuel stream is blo'wn' forwardly to a point in advance of the spark gap. The primary airA enteringV vthrough the openings 21 and 23 is insutlicient to support complete combuss tion o'f the vfuel andis moving at relatively slow'velooity. A portion of the fuel will burn to supply heat for 'the vaporization of the bulk of the fuel but the quantity of fuel burned in the vaporizing chamber is com- ,parativelysmalL -As the burning fuel mixture is deflected along the spiral path defined yby the chamber 15, the kinetic .energy due to .the velocit of the stream in a horizontal direction is isisi ated and the burning mixture of vaporized uel and air passes out of the horizontal path and through the burner open ings 27. The spiral shape of the vaporizing -chamber is an important feature of the invention,- since the travel of the burning stream along this pathresults in a substantially uniform upward pressure at the top wall 11 adjacent the inner wall 14 of the spiral chamber. As the upward pressure is substantially uniform the burning mixture passes through the openings 27 in uniform quantities to produce a symmetrical flame by combining with the secondary air which is supplied through the central passage of the burner. The flame is turned laterally by the deflector 31, which deflector may be adjusted to provide the most efficient combustion. The gas mixture which passes from the Vaporizing chamber 15 is of substantially homogeneous composition and the outlet opening, or openings, 27 are so spaced with respect to the secondary air passage that the rich mixture and the secondary air are combined in the proper proportion to secure an even flame around the head of the burner.

As stated above, the point of ignition of the flame is held in .advance of the fuel opening 20. In sonie installations the velocity of the burning stream necessary to secure this result is best obtained by contracting the walls of the air-projecting nozzle, as shown in Fig. 6.

It is to be understood that the invention is not limited to the specific embodiment hereinillustrated, since some changes in the relative size of the parts will usually .be required when a burner of a given size is to be used for different purposes. For instance, in adapting the burner illustrated for use with a materially greater quantity of fuel, it may be' necessary to increase the size of the

openings

20, 23, or to increase the number of such openings. If desired, `the air passages 2l and j 28 may be of such size as to pass the maximum desired quantity of air, and some of the passagesmay be closed in any suitable manner when the burner is put to a use which requires, a relatively small quantity of fuel.

These and many other changes in thesev- 'eral parts, their relative size, shape and location may be made within the scope of my invention as set forth in the following claims. I claim: f 1. The methody of burning non-volatile fuel, which lcomprises projecting liquidfuelv into a limited quantity of air, constraining the rich mixture to move along a spiral path of decreasing area in cross-section, igniting the fuel upon its entrance upon said spiral- I path, delivering the burning rich mixture in a direction normal to the plane of said spiral path, and supplying additional air to said burning rich mixture.

2. The method of burning non-volatile liquid fuel which comprises introducing a spray ofliquid fuel into a slowly moving and limited quantity of air, constraining the rich mixture to follow a horizontal spiral path of. decreasing cross-section, igniting'the fuel at the entrance of said path, delivering the burning rich mixture from said path near the axis thereof and in an upward direction, and

3., In a liquid fuel burner, a vaporizing chamber having walls defining a horizontallyarranged spiral path, means for establishing a stream of air and fuel traveling along said path and towards the center of the spiral, and outlet means at the top of said chamber adjacent the center of the spiral permitting the passage of the fuel mixture from the chamber.

4. In a burner for non-volatile liquid fuel, a vaporizing chamber having a top, a bottom and inner and outer side walls, said side walls being cylindrical and eccentrically arranged to define a spirally-shaped chamber, means for introducing a stream of fuel and air into and tangentially of said chamber at the widest portion thereof, and' an outlet for the fuel mixture Vthrough the top wall and adjacent said inner side wall.

5. The invention. as claimed in 'claim 4,

path along a line lying in advance of the fuel and `air supplying means.

6. In a fuel burner, a vaporizing chamber,

means for introducing a rich mixture of fuel and air into and horizontally of said chamber,

and a plurality of outlet openings in the top of said chamber, said chamber and said outlet means being constructed and arranged to effect the discharge through all of said outlet openings of'afuel mixture 'which is of homogeneous composition and at substantially uniform pressure.

7 A burnerfor non-vaporizable liquid fuel comprising a vaporizing chamber, means for? delivering liquid fuel and a quantity of air insufficient for the complete combustion thereof into said chamber, means for initiating the combustion of said mixture in said chamber to promote thevaporization of the fuel, outlet means permitting the passagefrom said chamber of the vaporized fuel mixture, and means for supplying additional air tosaid mixture as it issues from said chamber, said chamber and said outlet means being constructed and arranged to effect the discharge through all portions of said outlet means of 'a fuel mixturewhich is of homogeneous composition and at substantially uniform pressure.

8. In a'fuel burner, a v a'porizing chamber having a bottom wall, an approximately' cirino cularyside wall, and a top wall, a vertical air passage extending through said chamber and eccentrically thereof, inlets for introducing fluid fuel and air at the widest portionof the vaporizing chamber andfangentially thereof, and means permitting the passage of intermixed fuel and air through the top wall ofe said chamber adjacent said air assage.

9. In a fuel burner,'a burner ead having inner and outer walls approximately circular in horizontal cross-section, said wallsbelng eccentrically arranged to define a spirally- .shaped vaporizing chamber, a tangeritially arranged opening into said chamber at the widest portion thereof for the introduction of fuel and air, a top wall closing said inlet chamber and having means adjacent the inner wall of said chamber permitting the escape of the fuel mixture therefrom, a false bottom wall joining said inner and outer walls to close said vaporizing chamber, and a bottom wall cooperating with said outer wall to dene a secondary air chamber underlying` said vaporizing chamber, and a. deflector overlying thecentral opening and the outlet means' of said top annular Wall.

10. In a burner for non-volatile liquid fuel,

a vaporizing chamber having a top, a bottom andinner and outer side walls, said side walls being cylindrical and eccentrically arranged to define ya spirally-shaped chamber, means for introducing a stream of 'fuel and air into and tangentially of ,said chamber atthe widest portion thereof, an outlet for the fuel mixture through said top wall and adjacent the inner side wall, and a deflector positioned above said outlet for laterally directing the mixture issuingfrom said ontlet.

1l. The inventionl as set forth in claim 10, wherein means is provided for vertically adjusting said deflectorl with respect to said outlet. y

vmi

12.'V The invention as set forth in claim l0,

wherein a stud is arranged axially of said lspirally-shaped chamber, and said deiiector is adjustably mounted .on said stud.

In testimony whereof, I affix my signature. WILLIAM SCRIMGEOUR.