US3777678A

US3777678A - Cyclonic type fuel burner

Info

Publication number: US3777678A
Application number: US00152541A
Authority: US
Inventors: V Shanahan; R Mills; K Lutes; J Lander
Original assignee: MacMillan Bloedel Ltd
Current assignee: BREG JORG; MacMillan Bloedel Ltd; Moore Dry Kiln Company of Canada Ltd
Priority date: 1971-06-14
Filing date: 1971-06-14
Publication date: 1973-12-11
Anticipated expiration: 1990-12-11
Also published as: CA975222A

Abstract

The invention is directed to a fuel burner for combustible material, the burner having a horizontally disposed, circular combustion chamber into which all types of dry or semi-dry combustible material, including waste material, which has been reduced to small particulate size, or various types of combustible luquid wastes, together with air for supporting combustion, are injected tangentially into the combustion chamber. The invention is also directed to the method of burning combustible material and to the method of providing heat energy.

Description

United States Patent 1 Lutes et al.

[ Dec. 11, 1973 CYCLONIC TYPE FUEL BURNER [75] Inventors: Kenneth V. Lutes, Escondido; James E. Lander, San Clemente; Vincent J. Shanahan, Escondido; Richard G. Mills, Solana Beach, all of Calif.

[73] Assignee: Macmillan Bloedel Ltd.

[22] Filed: June 14, 1971 [21] Appl. No.: 152,541

[52] US. Cl 110/8 R, 110/28 F [51] Int. Cl. F23g 5/06 [58] Field of Search 110/8 C, 8 R, 28 F; 431/173 [56] References Cited UNITED STATES PATENTS 3,199,476 8/1965 Nettel 110/28 F 2,387,005 10/1945 Boedecker.. 110/18 R 2,881,720 4/1959 Lotz 110/28 F 1,618,808 2/1927 Burg 431/173 2,800,091 7/1957. Lutz 110/28 F 2,592,491 4/1952 Toepel 110/8 C 3,500,775 3/1970 Hubbard 110/8 R 2,769,411 11/1956 Simmons 431/173 Primary Examiner-Kenneth W. Sprague Assistant ExaminerJames C. Yeung Att0rneyCarl K. Brown and Neil F. Martin [57] ABSTRACT The invention is directed to a fuel burner for combustible material, the burner having a horizontally disposed, circular combustion chamber into which all types of dry or semi-dry combustible material, including waste material, which has been reduced to small particulate size, or various types of combustible luquid wastes, together with air for supporting combustion, are injected tangentially into the combustion chamber. The invention is also directed to the method of burning combustible material and to the method of providing heat energy.

10 Claims, 8 Drawing Figures PAIENTEBUEC n ma (777,678 SHEET 1m 4 a9 94 a7 96 L /56 3 76 FIG. I

% KENNETH V. LUTES JAMES E. LANDER L BY RICHARD e. MILLS M H1 ATTORNEY.

INVENTORS.

VINCENT J. SHANAHAN akntsTa 81113 2 CF 4 PAIENIEDDEB 11 I975 JAMES E. LA-NDER VINCENT J. SHA NAHAN BY wcHARo e. MILLS W ATTORNEY.

PAIENIEBHEI: n ma 3777.678

I NVENTORS KENNETH V. LUTES JAMES E. LANDER VINCENT J. SHANAHAN R/cHAFw G. MILLS BY {Mm #1 1 ATTORNEY.

PAIENIED DEC 1 1 I975 SHEET 4 LF INVENTORS KENNETH V LUTES JAMES E. LANDER VINCENT J. SHANAHAH BY RICHARD G. MILLS WWI m HZ/YafiMi/MMTTORNEX 1 CYCLIONIC TYPE FUEL BURNER BACKGROUND OF THE INVENTION tion chamber adjacent that end wall. In the present invention, the combustible material can enter the combustion chamber tangentially, and the air is distributed to that chamber at a plurality of areas along the length of the chamber. Also, the air pressure, velocity and volume can be varied as desired in those areas.

SUMMARY OF THE INVENTION The invention relates to a cyclonic type fuel burner in which the combustible materials aforesaid are injected tangentially into a horizontally disposed combustion chamber to impart whirling movement to the combustible material. The whirling movement is augmented by injecting air tangentially into the combustion chamber at different areas throughout the length of the combustion chamber, the injected air also providing the air for supporting combustion. The air pressure, velocity and volume in the various areas along the combustion chamber can be varied to thereby effect the desirable flame lengths.

The construction of the burner is such that the refractory walls thereof are heated to such high degree that the combustible material is heated to kindling temperature whereby, after starting the burner, the pilot flame can be extinguished.

The invention is directed also to a burner of the type which can be used in multiple for preheating the wall, for example of a tepee-type incinerator.

Other features and the advantages of the present invention will be apparent from the following description, reference being made to the accompanying drawings wherein a preferred embodiment of the invention is illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of the cyclonic type fuel burner and the blower for injecting air into the combustion chamber of the burner;

FIG. 2 is a side view of the apparatus shown in FIG. 1;

FIG. 3 is a sectional view of the burner taken along line 33 of FIG. 1, but showing the same on a larger scale, the view also showing the blower in elevation;

FIGS. 4 and 5 are sectional views taken along lines 4-4 and 5-5, respectively, of FIG. 3;

FIG. 6 is a fragmentary sectional view taken along line 66 of FIG. 1;

FIG. 7 is a sectional view of an incinerator of the tepee type showing two of the present burners in posi tion; and

FIG. 8 is a sectional view taken along line 8-8 of FIG. 7. v

DESCRIPTION OF THE PREFERRED EMBODIMENT The cyclonic burner 20 comprises a relatively elongated, circular, and preferably cylindrical wall 22 which is horizontally disposed, a front end wall 24 and a rear end wall 26. These walls are formed of desirable refractory material and form a combustion chamber 28. As seen in FIG. 3, the front end wall is provided with an opening 30 for receiving air and a pilot burner 32. The cylindrical wall, as seen in FIG. 4, is provided with a tangentially disposed opening 34 which receives a metal tube 36. The rear end wall 26 is provided with a centrally disposed opening 38 that forms the outlet for the combustion chamber 28.

A sheet metal wall 40 encircles the refractory wall 22. A ring 42 of sheet metal surrounds the front wall 24 and a ring of sheet metal 44 surrounds the rear wall 26. Rings 42 and 44 are fixed, respectively, to the front and rear ends of the encircling wall 40. The cylindrical wall 22 and the encircling wall 40, as shown in FIGS. 3 and 5, are provided with a plurality of openings 46 that extend through the wall 22. These openings 46 are tangentially disposed along the length of that wall 22 for directing air tangentially into the combustion chamber along the length thereof.

A plurality of heat

insulating sections

48, 50 and 52 surround the combustion chamber 28.

Sections

48, 50 and 52 include, respectively, cylindrical

heat insulating walls

54, 56 and 58 that are spaced radially from the combustion chamber 28; these sections also include, respectively, surrounding

sheet metal walls

62, 64 and 66. A ring 68 of sheet metal closely embraces the sheet metal wall 40 and is disposed between

sections

48 and 50, and a like ring closely embraces the sheet metal wall 40 and is disposed between

sections

50 and 52.

Sheet metal walls

62 and 64 and ring 68 are suitably sealed with one another, and

sheet metal walls

64 and 66 and ring 70 are sealed with one another.

An insulating wall 72 covers the front refractory wall 24 and a sheet metal wall 74 covers thelinsulating wall 72 and is sealed to the front end of the circular sheet metal wall 62. A sheet metal wall 76 covers the rear wall 26 of the combustion chamber and is sealed to the rear end of the sheet metal wall 66. Thus the area between the sheet metal 40 and ring 42 that surrounds the combustion chamber, the heat insulation 48, the sheet metal cover 74, and the ring 68 form a cylindrical air chamber 78. The area between the sheet metal 40, the insulation and the rings 68 and 70 form a cylindrical air chamber 80. The area between the sheet metal 40, the rings 44, the insulation 58 and the rear end cover 76 form a cylindrical air chamber 82.

Air chambers

78, 80 and 82 are onnected, respectively, to an air pipe 84 by manifold air pipes, each of which includes two sections 86-87, 88-89 and 90-91, respectively. These pipes are provided, respectively.

' with air

flow control valves

96, 94 and 92 (see FIGS.

'

pipes

84, 86, 88 and 90. By adjusting the valves the air pressure, velocity and volume can be controlled in the

air chambers

78, 80 and 82 resulting in the admission of desired different pressures,velocity and volumes of air along, the interior of the combustion chamber. In this m'a'nn'er, the-length of the flame can be controlled and combustion can be optimized. If desirable, the flame can be extended variable lengths beyond the combustion chamber 28; or when the burner is employed as an air heater, the air flows to the combustion chambers can be varied so that the flame is confined within the combustion chamber.

The combustible material to be burned is injected by any of the well known force-feeding mechanisms, for example, such as that shown in the aformentioned Patent to Burden, .lr., et al., No. 3,453,976 or the Patent to Burden, Jr., No. 3,472,185 However, in the present apparatus, the material to be burned enters tangentially into the combustion chamber through the tube 36 that is disposed tangentially with respect to the interior circular wall 22 of the combustion chamber.

Thus it is apparent from the foregoing that by tangentially injecting the combustible material, which is to be burned in the combustion chamber 28, whirling movement will be imparted to the material as it is being burned and the whirling movement is augmented continuously throughout the length of the combustion chamber by imparting tangential movement to the air through the outlets of the tangentially disposed openings 46 in the circular wall 22. This air functions both as primary combustion air and as air for conveying combustible material through the combustion chamher. The control of this air determines retention time of the combustible material in the combustion zone of the combustion chamber.

It has been discovered that these burners are of particular value for preheating an incinerator device such as, for example, the tepee or wigwam burner shown in FIGS. 7 and 8. The tepee type incinerator 102 disclosed herein includes the frustoconically shaped sheet metal skin 104, the top 106 of which is open to atmosphere.

The periphery of the pile of combustible material 118 is spaced inwardly of the incinerator skin 104 to provide a space 120 surrounding the pile. A plurality of burners 20, preferably three, are disposed, as shown in FIG. 8, in positions for directing hot air, emanating therefrom tangentially, into this space 120. The air

flow regulating valves

92, 94 and 96 are adjusted so that flames emanating from the burner do not extend to the pile and are contained within the burners.

The base of the incinerator 102 carries the usual perforated air chamber 122 above which the combustible material 118 is piled. Air for supporting combustion is delivered to the chamber 122 under pressure through a pipe 124.

It has been found that all tepee type incinerators emit trememdous and objectionable volumes of heavy and dense smoke during periods when the temperature of the steel skin of the tepee is cold, such as at the time the pile of waste material is first lit or fired, or at any time while the tepee is in operation and when the amount of waste material that is being fed into the tepee is not sufficient to maintain a degree of temperature sufficiently high to maintain the skin of the tepee uniformly hot. It has been found that the temperature of the steel skin must be maintained at approximately 400 F. around the lower three-fourths of the structure and at approximately 750 F. at the top or crown of the structure in order to promote good combustion within the structure and to burn the smoke generated by'the burning pile of waste material.

The cyclonic type combustible material burner, as herein illustrated, provides an excellent burner for the method of preheating the steel skin of the tepee type incinerator; and by the use of regulating

controls

92, 94 and 96, a method of maintaining the skin temperature at required levels throughout the entire operating period of the tepee incinerator is achieved. This is particularly true when a plurality of burners, such as shown in FIG. 8, are employed.

It will be understood by those skilled in the art that the herein-disclosed waste fuel burner can be applied in boilers as overfire for smoke elimination and as a prime B.T.U. source for boilers, dryers, kilns, etc.

It is to be observed, particularly from FIG. 3, that the outlet 38 of the rear refractory wall 26 of the combustion chamber 22 is restricted to provide a choke at the exit of the combustion chamber. It has been found that by choking or restricting the outlet of the combustion 'chamber, the refractory walls can be heated to such high value that the combustible material is raised to its kindling temperature. By this phenomenon there is no need for maintaining the flow of extraneous fuel such as gas or oil that is used for starting the operation of the burner. From the foregoing, the burner uses only combustible waste material after the burner becomes operative, resulting in minimizing the requirement of extraneous fuels. Thus the burner, after being started, uses only waste and converts this waste into useful energy.

lt will be understood by those skilled in the art that standard control instruments are employed for controlling the burner, such as thermostats, etc., when the burner or burners are rendered operative and inopera' tive for maintaining temperature between limits. Such standard control instruments also control the timing of blowers, ignition, etc.

The word shredded as used herein includes sawdust, or dry or semi-dry combustible waste which has been pulverized, ground, milled or otherwise reduced to small particulate sizes so as to be capable of being suspended in a stream of air.

Thus, from the foregoing it is apparent that by virture of the present invention, there has been provided a burner for combustible material, such as sawdust, waste products, etc., in which air for supporting combustion is supplied substantially throughout the length of a horizontally disposed combustion chamber. This air in addition to its function of supporting combustion, imparts whirling movement to the combustible material, which was injected tangentially into the combustion chamber, throughout the horizontal length of the chamber.

Also, by providing separate air feeding chambers through the length of the combustion chamber, by suitable regulatable valves, the length of the flame generated in the chamber can be varied as desired. Thus, for example, if the burner is employed as an air heater, the flame can be contained within the chamber.

Too, the burner or burners can be utilized as preheaters of combustible material that is to be incinerated, the effect of which is to minimize the generation of unburned combustible materials and unburned combustible gases.

Having described our invention, we claim:

1. Apparatus for burning combustible material, said apparatus comprising:

A. a substantially horizontally disposed, circular combustion chamber formed by:

l. a refractory front wall,

2. a refractory rear wall having an outlet opening,

3. a substantially horziontally disposed, circular wall formed of refractory material, said latter wall being jointed with the front and rear walls, said material of the substantially circular wall having a plurality of tangentially disposed openings therethrough spaced along the length thereof, said circular wall having a separate opening therein disposed for admitting combustible material tangentially into the combustion chamber;

B. means substantially surrounding the circular refractory material, said meansbeing spaced from the circular refractory material providing an air space in open communication with the tangentially disposed opening in the circular refractory material;

C. means for injecting combustible material through said combustible material opening;

D. means for injecting air into the space lying between the refractory material and the first mentioned means.

2. Apparatus as defined in claim 1, characterized in that the first mentioned means includes heat insulation substantially surrounding the refractory material.

3. Apparatus as defined in claim 2, characterized to include:

E. means for dividing the circular air space into a plurality of longitudinally disposed air chambers, each in open communication with the tangentially disposed opening in the insulating material.

4. Apparatus as defined in claim 1, characterized in that the opening for combustible material is disposed in the substantially circular wall adjacent the front wall.

5. The steps in the method of burning waste combustible material in a combustion chamber formed of a horizontally disposed, substantially circular wall and a rear wall, the circular wall having an opening and an air chamber disposed longitudinally of the combustion chamber, which steps comprise:

A. forcing combustible material under pressure through an opening in the circular wall of the chamber adjacent the front wall of the chamber, which opening is tangentially disposed relative to said circular wall to cause the combustible material to whirl within the combustion chamber;

B. igniting the combustible material adjacent the opening;

C. supplying the necessary air to said combustion chamber through separate openings through said circular wall from the longitudinally disposed air chamber for supporting combustion of the combustible material and augmenting the whirling of the combustible material by imparting tangential movement of the air that enters through the longitudinally disposed air chamber and separate along the periphery of the combustion chamber;

D. exhausting burned gases through the opening in the rear wall of the combustion chamber.

6. The steps in the method as defined in claim 5 characterized to include the step of regulating the length of the flame which is produced by the burning particles, which step comprises:

E. varying the relative quantities of air flowing to the longitudinally disposed air supplying chambers to retain the flame within the confines of said combustion chamber.

7. The steps in the method of burning waste combustible material, which steps comprise:

A. placing the combustible material in an area that is spaced from and surrounded by a wall;

B. preheating the wall by injecting a plurality of streams of heated air from a plurality of burners tangentially into the area between the combustible material and the wall;

C. regulating the burners to prevent flames from flowing into the area;

D. thereafter regulating the burners to heat the combustible material to a kindling temperature, and

E. supplying air from an air outlet on the longitudinal center of the volume enclosed by the Wall.

8. The steps as defined in claim 7, characterized in that the wall is the steel skin of the lower section of a tepee type incinerator and that the temperature of the skin is preheated to approximately 400F. prior to heating the combustible material to a kindling temperature.

9. The steps as defined in claim 7, characterized in that the wall is the steel skin of the lower section of a teepee type incinerator and that the temperature of the skin, after once being preheated to approximately 400F., is maintained at that temperature.

10. The steps as defined in claim 7, characterized in that the wall is the steel skin of a teepee type incinerator and that the temperature of the lower section of the skin is preheated to approximately 400F. prior to heating the combustible material and after once being preheated to approximately 400F., is maintained at that temperature and the crown of the skin is maintained at approximately 750F.

Claims

1. Apparatus for burning combustible material, said apparatus comprising: A. a substantially horizontally disposed, circular combustion chamber formed by: 1. a refractory front wall, 2. a refractory rear wall having an outlet opening, 3. a substantially horziontally disposed, circular wall formed of refractory material, said latter wall being jointed with the front and rear walls, said material of the substantially circular wall having a plurality of tangentially disposed openings therethrough spaced along the length thereof, said circular wall having a separate opening therein disposed for admitting combustible material tangentially into the combustion chamber; B. means substantially surrounding the circular refractory material, said means being spaced from the circular refractory material providing an air space in open communication with the tangentially disposed opening in the circular refractory material; C. means for injecting combustible material through said combustible material opening; D. means for injecting air into the space lying between the refractory material and the first mentioned means.

2. a refractory rear wall having an outlet opening,

3. Apparatus as defined in claim 2, characterized to include: E. means for dividing the circular air space into a plurality of longitudinally disposed air chambers, each in open communication with the tangentially disposed opening in the insulating material.

3. a substantially horziontally disposed, circular wall formed of refractory material, said latter wall being jointed with the front and rear walls, said material of the substantially circular wall having a plurality of tangentially disposed openings therethrough spaced along the length thereof, said circular wall having a separate opening therein disposed for admitting combustible material tangentially into the combustion chamber; B. means substantially surrounding the circular refractory material, said means being spaced from the circular refractory material providing an air space in open communication with the tangentially disposed opening in the circular refractory material; C. means for injecting combustible material through said combustible material opening; D. means for injecting air into the space lying between the refractory material and the first mentioned means.

5. The steps in the method of burning waste combustible material in a combustion chamber formed of a horizontally disposed, substantially circular wall and a rear wall, the circular wall having an opening and an air chamber disposed longitudinally of the combustion chamber, which steps comprise: A. forcing combustible material under pressure through an opening in the circular wall of the chamber adjacent the front wall of the chamber, which opening is tangentially disposed relative to said circular wall to cause the combustible material to whirl within the combustion chamber; B. igniting the combustible material adjacent the opening; C. supplying the necessary air to said combustion chamber through separate openings through said circular wall from the longitudinally disposed air chamber for supporting combustion of the combustible material and augmenting the whirling of the combustible material by imparting tangential movement of the air that enters through the longitudinally disposed air chamber and separate along the periphery of the combustion chamber; D. exhausting burned gases through the opening in the rear wall of the combustion chamber.

6. The steps in the method as defined in claim 5 characterized to include the step of regulating the length of the flame which is produced by the burning particles, which step comprises: E. varying the relative quantities of air flowing to the longitudinally disposed air supplying chambers to retain the flame within the confines of said combustion chamber.

7. The steps in the method of burning waste combustible material, which steps comprise: A. placing the combustible material in an area that is spaced from and surrounded by a wall; B. preheating the wall by injecting a plurality of streams of heated air from a plurality of burners tangentially into the area between the combustible material and the wall; C. regulating the burners to prevent flames from flowing into the area; D. thereafter regulating the burners to heat the combustible material to a kindling temperature, and E. supplying air from an air outlet on the longitudinal center of the volume enclosed by the wall.

8. The steps as defined in claim 7, characterized in that the wall is the steel skin of the lower section of a tepee type incinerator and that the temperature of the skin is preheated to approximately 400*F. prior to heating the combustible material to a kindling temperature.

9. The steps as defined in claim 7, characterized in that the wall is the steel skin of the lower section of a teepee type incinerator and that the temperature of the skin, after once being preheated to approximately 400*F., is maintained at that temperature.

10. The steps as defined in claim 7, characterized in that the wall is the steel skin of a teepee type incinerator and that the temperature of the lower section of the skin is preheated to approximately 400*F. prior to heating the combustible material and after once being preheated to approximately 400* F., is maintained at that temperature and the crown of the skin is maintained at approximately 750*F.