US3540709A

US3540709A - Combustion assembly

Info

Publication number: US3540709A
Application number: US702991A
Authority: US
Inventors: Ernest A Gardner; Harold E Fisher
Original assignee: MECHTRON GENCO CORP
Current assignee: MECHTRON GENCO CORP
Priority date: 1968-02-05
Filing date: 1968-02-05
Publication date: 1970-11-17
Anticipated expiration: 1987-11-17

Description

' United States Patent inventors Appl. No. Filed Patented Assignee COMBUSTION ASSEMBLY 19 Claims, 10 Drawing Figs.

U.S. Cl.

Int. Cl. F27b 7/00 Field of Search 43l/l59, 161, 164, I66, 188; 263/32, 33,19

References Cited Primary Examiner-Edward G. Favors Attarney- Yount, Flynn & Tarolli ABSTRACT: Disclosed herein is a combustion assembly wherein fuel is at least partially burned. The preferred combustion assembly includes an outer housing or shell formed by a plurality of plates and an inner liner or shell formed by a plurality of segments which are connected to the plates. The segments are spaced apart from the plates of the housing to provide air passages or spaces between the housing and liner. A segment mounted on one of the plates is spaced apart from the segments mounted on adjacent plates to provide for thermal expansion of the liner. The plates and the segments of the housing and liner are releasably interconnected to facilitate assembly and maintenance.

Patented Nov. 17, 1970 Sheet FIG! INVENTORS ERNEST A. GARDMER HAROLD E FISHER ATTORNEYS Patent ed Nov. 17, 1970 FIGES INVENTORJ ERNEST A. GARDNER HAROLD s. FISHER wwm 4M ,4 TTOENEYS Patented Nov. 17, 1970 Sheet 4' 014 INVENTORJ ERNEST A. GARDNEE HAROLD 5. FISHER ATTORNEYS of the ignition section;

COMBUSTION ASSEMBLY This invention relates generally to a combustion assembly and particularly to a combustion assembly adapted for use in a dryer.

Dryer assemblies for bituminous aggregates commonly include an ignition port or section where fuel from a burner unit is ignited before burning in a combustion chamber. Once the ignited fuel reaches the combustion chamber, it is burned to provide heat for drying the aggregate. Air is mixed with the fuel as the fuel flows through the ignition section to promote burning of the fuel in the combustion chamber. These known dryer assemblies have proved to be generally satisfactory for drying aggregates. However, the ignition sections and combustion chambers of most dryer assemblies include a relatively heavy refractory lining which is provided to withstand high temperatures resulting from the burning of the fuel. These refractory lined ignition sections and combustion chambers are subject to thermal distortion and stresses which result in their requiring maintenance after a period of use.

Therefore, it is an object of this invention to provide a new and improved combustion assembly including a relatively lightweight outer housing and liner formed by a plurality of metal plates which are readily assembled and disassembled for shipment, installation, and maintenance.

Another object of this invention is to provide a new and improved combustion assembly for a dryer and which is subject to a minimum of thermal stress and distortion.

Another object of this invention is to provide a new and improved combustion assembly for a dryer and which is constructed of easily replaceable parts to enable repairs to be made by replacing a defective part without replacing the entire assembly.

Another object of this invention is to provide a new and improved combustion assembly having parts subjected to relatively severe operating conditions made of special and durable alloys while other parts subjected to less severe operating conditions are made ofless expensive materials.

Another object of this invention isto provide a new and improved combustion assembly which can be readily lengthened or shortened by theaddition or subtraction of rings or seg mcnts.

Another object of this invention is to provide anewcornbustion assembly comprising an ignition section with an improved passage arrangement for the flow of air into the fuel.

Another object of this invention is to provide a new and improved ignition section which has a housing made up of a plurality of interconnected plates and a liner located within said housing and formed by a plurality of segments each of which'is mounted on one of said plates.

A further object is the provision ofa new and improved ignition section of a dryer and which includes an inner liner spaced from an outer shell to provide air flow therebetween and into a combustion chamber and wherein the air flow may be readily controlled.

These and other objects and features of the invention will become more apparent upon a consideration of the following detailed description taken in connection with'the accompanying drawings wherein:

FIG. 1 is a schematic illustration ofa dryer including a combustion assembly forming a preferred embodiment of the invention;

FIG. 2 is an enlarged sectional view, taken along a line 2-2 of FIG. 1, illustrating the structure of an ignition port or section of the combustion assembly;

FIG. 3 is a partially broken away elevational view, taken I FIG. 4 is a sectional view, taken along a line further illustrating the structure of the ignition section;

FIG. 5 is an enlarged elevational view, taken along a line 5-5 of FIG. 1, illustrating the structure of a combustion chamber;

FIG. 6 is a sectional view of a portion of the combustion chamber of FIG. 5;

4-4 of FIG. 2,v

FIG. 7 is an enlarged fragmentary sectional view of a portion ofthe combustion chamber of FIG. 5;

FIG. 8 is a fragmentary sectional view of a modified ignition port embodying the present invention;

FIG. 9 is a view of the ignition port of FIG. 8 looking at the ignition port of F IG. 8 along line 9-9 thereof; and

FIG. 10 is a view of a modified combustion chamber.

The combustion assembly of the present invention may be embodied in different environments and may in particular be embodied in an ignition port for a dryer in which fuel is ignited or in a dryer combustion chamber in which the ignited fuel is burned. The ignition section and combustion chamber, of a dryer embodying the present invention, both include outer housings or shells formed by a plurality of interconnected plates. An inner shell or'liner is located within each of the housings in a coaxial relationship with the associated housing. These liners are formed of a plurality of segments each of which is mounted on one of the plates of the associated housing. The segments of the liners mounted on one plate of a housing are spaced apart from segments of the liner mounted on adjacent plates of'the housing to provide for thermal expansion of the segments of the liner.

Although it is contemplated that combustion assemblies embodying the present invention will be used in many dif ferent environments, a typical combustion assembly 10 forming a preferred embodiment of the invention is shown in FIG. 1 in connection with a bituminous aggregate dryer assembly 12. The dryer assembly 12 includes a main dryerbody or section 14 which is mounted on a base or frame 16. Bituminous aggregate enters the dryer body 14 through a material inlet portion 18 and flows through the dryer body 14 to an outlet portion 20, as indicated by arrows in FIG. 1.

A burner unit 24 is provided for supplying a flow of fuel to the combustion assembly 10. Operation of the burner units 24 is regulated by controls which are illustrated schematically at 26 in FIG. 1. Fuel flowing-from the burner unit 24 is ignited in an ignition port or section 30 of the combustion assembly 10 and then flows into a combustion chamber or section 32 where the fuel is burned to provide heat to dry the. aggregate flowing through the dryer body 14. A flame 34 resulting from the burning of the fuel, extends from the ignition section 30 through the combustion chamber 32 and into the dryer body 14 where the aggregate is dried.

Air is mixed with fuel from the burner unit 24 and the fuel 2 tion section. The longitudinally extending sides of the plates 40 are spaced apart, as indicated at 44 in FIG. 2, to provide for expansion of the plates and thereby reduce thermal stresses in the housing 36 when it is heated. The plates 40 are interconnected by longitudinally extending generally V-shaped splice or connector plates 46.

An inner shell or liner 50 is provided within the housing 36 to define an ignition area and to direct the flow of burning fuel into the combustion chamber 32. To this end, the inner shell or liner 50 has the general configuration of a hollow frustrum of a cone and is located in a coaxial relationship with the housing 36. The liner 50 is generally funnel shaped, which varies with design considerations, and has a relatively small inlet opening 54 through which fuel from the burner unit 24 flows into the ignition section 30. The fuel is mixed with air and ignited within the ignition section 30. The ignited fuel air mixture then flows outwardly through a relatively large outlet end 1 seem bly of ignitionsection's of different sizes, since a greater or lesser number ofiayers orrings 64 can be provided depending upon the desired axial length of the ignition section 30. Each of the segments 60 is mounted on one of the plates 40 of the housing 36 by a plurality of connector assemblies 66 which also serve to connect the splice plates 46'with the plates 40 (see FIGS. 24). The liner segments 60 mounted on one of the plates 40 are spaced apart from the liner segments mounted on a next adjacent plate 40 so that the segments 60 mounted on one plate 40 of the housing are spaced apart by longitudinally extending slots or openings 70 from the segments 60 mounted on adjacent plates of the housing. The slots or openings enable the plates 60 to expand sidewardly when the liner 50 is heated to thereby minimize thermal stresses within the liner and distortion of the liner. Although the segments 60 have been shown with their axial ends in abutting relationship, it will be apparent to those skilled in the art that the axial ends of the segments 60 can be spaced apart from each other to provide for axialexpansion of the segments.

As is perhaps best seen in FIG. 4, the connector assemblies 66 each include a stud 74 extending from the outer surface of the segments 60 and through an associated plate 40 and splice plate 46 of the housing 36. A threaded outer end portion of the stud 74 is engaged by a nut 76 which presses the associated plate 40 and splice plate 46 against a nut 80 located on the stud 74 between an outer surface of the segment 60 and an inner surface of the plate 40. This construction is such that the liner 50 is held in a spaced-apart relationship relative to the housing 36 to provide a longitudinally and circumferentially extending generally cone-shaped air space or passage 84 defined by an outer surface of the liner 50 and an inner surface of the housing 46. The air space or passage 84 insulates the liner 50 to minimize heat loss and also to control inner segment temperature and preheat a part of the combustion air during operation. This preheating of the combustion air greatly adds to the efficiency ofthe unit.

The liner 50 projects somewhat beyond the housing 36 to provide an annular inlet or opening 88 (see FIGS. 3 and 4) at one end of the ignition section 30 and an outlet at the other end. Moreover, the liner 50 thus shields the housing 36 from excessive heat. The annular opening 88 enables air from the surrounding atmosphere to be inspirated or drawn into the passage 84. The passage 84 also would function to direct forced air into the combustion chamber.

Unburned fuel frequently collects along the lowermost segments 60 of the liner (indicated at 90 in FIG. 2) when the burner unit 24 is shut down and started up. During operation of the dryer assembly 12, this unburned fuel is'ignited and provides particularly severe operating conditions for these segments. Therefore, the lowermost segments 60 are advantageously formed of'a durable, heat-resistant alloy material which has a relatively long service life under the severe operating conditions to which theseparticular segments are subjected. The other segments 60 of the liner are subjected to less' severe operating conditions and are advantageously formed ofa less expensive material which provides satisfactory service under the less severe operating conditions to which these other segments are subjected. The formation of different sections of different materials'is facilitated by the previously described connection of each segment of the liner with a plate 40 ofthe housing. a

In view of the foregoing description, it will be apparent that the ignition port 30 reduces thermal stresses and distortion by the mounting of each of the segments 60 of the liner on one of the plates 40 of-the housing and spacing the segments of the liner apart from segments mounted on adjacent plates 40. Moreover, due to the segmented construction of the ignition port 30, it can be readily shipped and assembled without the need of special handling equipment, such as a crane.

The structure ofa preferred embodiment ofthe combustion chamber 32 is fully disclosed in FIGS. 7. The combustion chamber 32 is similar in structure to the ignition section 30 and includes a strong, protective cylindrical outer housing or shell 96 formed by a plurality of plates 100. The plates 100 are movably supported by longitudinally extending, generally T- shaped mounting or support members or beams 104 which extend parallel to a central axis of the combustion chamber 32. The support member 104 are fixedly connected to a wall or frame 106 which interconnects the combustion chamber 32 and a main body 14 of the dryer assembly 12 (see FIGS. 1 and A cylindrical liner or inner shell 108 is located within the housing 96 in a generally coaxial relationship with the housing. The liner 108 is made up of a plurality of arcuate, generally rectangular segments or plates 110, each of which is mounted on one of the plates ofthe housing 96, Although only one-half of the liner 108 and housing 96 has been shown in detail in FIG. 5 it will be understood that both halves of the liner and housing are. of the same construction.

The sides and ends of the segments 110 may be spaced somewhat to provide for thermal expansion of the segments 110. The segments 110 of the combustion chamber 32 are arranged in rings or layers, in the same manner explained in connection with the ignition section 30, to facilitate the assembly of the combustion chamber.

Each of the segments 110 is fixedly connected to and associated with a plate 100 of the housing 96 by a connector assembly 114 (see FIG; 6), including threaded studs 116 which. extend outwardly from an outer surface of the segments 110.

Suitable nuts are threaded onto the studs 116 to mount the segments 110 in a spaced-apart relationship relative to the associated plate 100 to provide a cylindrical heat-insulating air space 120 extending for substantially the entire length of the combustion chamber 32. Slots or openings 124 between the ends and sides of the segments 110 provide communication between the air space 120 and the interior of the combustion chamber 32. Of course, the segments 110 can be made of different materials to compensate for variations in the severity of operating conditions within the combustion chamber 32 in much the same manner as previously explained in connection with the ignition section 30.

In order to minimize thermal stresses and distortion, the plates 100 of the housing 96 are slidably connected to the support members 104 to enable the plates 100 to expand and contract relative to the support members 104 during operation of the dryer assembly 12. To this end, the plates 100 are slidably retained against an outer surface (see FIG. 7) of a head section 132 ofthe generally T-shaped support member 104 by a pair of positioning .sections or members I32. The sections 136 extend outwardly from a stem portion 138 of the support member 104 and slidably engage an outer surface of the plates 100. During operation of the dryer assembly 12, the plates 100 of the housing 96 expand and contract with a resulting movement relative to the support members 104, as indicated by the arrows 140 in FIG. 7. The sliding connections between the support members 104 and the plates 100, and the slots 124 between segments 110 of the liner 108 enable the plates 100 to expand and contract without creating excessive thermal stresses in either the housing or the liner. Of course, the housing 36 of the ignition section 30 could if desired, be constructed in the same manner as is the housing 96 of the combustion chamber 32.

Since the ignition section 30 and combustion chamber 32 are fabricated by releasably interconnecting a plurality of plates and segments with

connector assemblies

66 and 114, respectively, the ignition section and combustion chamber are readily assembled at a manufacturing plant for test purposes, subsequently disassembled and shipped in pieces to a customers plant and reassembled. Prior to the present invention, it was a common practice to build the ignition section 30 and combustion chamber 32 with a relatively heavy refractory lining which prohibited the assembly and disassembly of the ignition section and combustion chamber. Therefore, these heavy refractory liner ignition sections and combustion chambers were previously shipped as heavy and bulky components of the dryer assembly 12. In addition to facilitating assembly and disassembly, the building of thecombustion assembly of a plurality of releasably interconnectedplates and segments enables the combustion assembly to be readily repaired or maintained. If one of the segments of the liner or a plate of the housing should break down or deteriorate during use, that segment or plate of the combustion assembly can be easily replaced without necessitating the replacement. of the entire ignition section or combustion chamber. Also, the size of the combustion assembly 10 can be readily changed by merely varying the length ofthe housings and the numberof segments provided in the liners.

A further embodiment of an ignition port embodying the present invention is illustrated in FIG. 8. The ignition port illustrated in FIG. 8 is generally designated 2 00 and is constructed in a manner similar to the construction described hereinabove in connection with FIG. 2, and, therefore, a detailed description of the ignition port construction will not be repeated here. The basic difference between the ignition port 200 and the ignition port described hereinabo ve is the fact that the ignition port 200 is provided with means which is adjustable to control the flow of air into the combustion chamber and ignition port. I

More specifically, the ignition port 200 includes an outer shell 201 and a liner 202 which is made up ofa plurality ofsegments which segments are secured to plates forming the outer 1 shell 201, all as described hereinabove in connection with FIG. 2. The liner 202 is spaced from the shell 201 to define a fluid passageway 203 therebetween through which air may be directed into a combustion chamber 205 shown schematically in FIG. 8. The passageway 203 is adjustable, as described hereinabove, through the use of suitable adjustable connecting elements between the liner 202 and shell 201.

In addition to the adjustment of. the air flow through the passageway 203, the ignition port 200 is provided with a baffle structure, generally designated 210, and mounted adjacent the burner 211, as shown in FIG. 9. The baffle construction 210 comprises a plurality of plate members 212 which are mounted in association with the outer shell 201 so as to define a complete annular baffle which extends around the ignition port 200. The plates. 212 are securedby means of suitable fasteners, such as bolts 213, to an angle support member 214 which, in turn, is secured by suitable bolts to the outer ,shell 201. The bolts 213 extend through slots in the angle support member 214 to thereby provide for adjustment of the plate 212 toward and away from the burner 21], as indicated by the arrows 215 in FIG. 8.

By movement of the plate 212 vertically along the angle support member 214, the space designated A in FIG. 8 can be adjusted. By adjusting the space A, the air flow around the burner 211 and into the ignition port can be controlled. Even though the air flow through the space A may be completely closed, air would still be inspirated, or directed, into the passageway 203 through the space designated B in FIG. 9.80, therefore, while the plates 212 do effect a control of the air through the space A by adjustment thereof, their effect on the space B by adjustment is negligible.

The right end of the ignition port200, as illustrated in FIG. 8, also is provided with ,an adjustable baffle or control means 220 for controlling the flow of air into the combustion chamber. The construction of the baffle 220 is similar to that of the baffle 210 and the baffle 220 includes a plurality of plates 221, each of which is secured to an angle support member 222 by a plurality ofbolts or fasteners 223 which extend through a slot in the angle support member 222. The angle support member is, in turn secured by bolts to the outer shell 20]. The bolts 223 extend through slots in the angle support member 222 and provide for generally radial adjustment of the plates 221 relative to the ignition port 200. By adjusting theplates 221 radially the flow of air between the plates 221 and the combustion chamber in the area designated C can be controlled. Likewise, the flow of air through the space designated D can be controlled by adjustment of the plates 222. It should, therefore, be apparent that the ignition port combustion chamber 240, illustrated in FIG. 10, results in the flame being deflected upwardly in the combustion chamber 240 and even associated therewith, and as a result affects the efficient and proper drying of the aggregate in the dryer. Asa result it is extremely desirable to periodically remove or provide some arrangement for eliminating this buildup of material in the combustion chamber 240. The buildup of the material in the combustion chamber 240 is, in the embodiment illustrated in FIG. 10, eliminated by the provision of a plow or similar device 251 fixedly mounted in the combustion chamber, and the rotative mounting of the combustion chamber 240. By rotating the combustion chamber 240 relative to the fixed plow 251, any material, such as material 250 shown in FIG. 10, would be pushed off the bottom of the combustion chamber and into the dryer, and thus minimize the aforementioned problem of flame deflection. The rotation of purposes of illustration and many different arrangements may be effected for rotating the combustion chamber 240.

Although the combustion assembly 10 has been illustrated in connection with adryer assembly 12 for drying aggregate, it.

will be apparent to those skilled in the art that the combustion assembly 10 can be used in many other environments. It will also be apparent to those skilled in the art that the particular configuration of the ignition section 30 and combustion chamber 32 can be varied to suit the particular environment in which the combustion assembly is to be used. Of course, the illustrated preferred structure of the ignition section and combustion chamber can vary. Thus, while a particular embodimerit of the invention has been shown, it should be understood, of course, that the invention is not limited thereto since many modifications may be made. It is therefore, contemplated to cover by the appended claims any such modifications as fall within the true spirit and scope of the invention.

We claim:

1. A combustionassembly comprising an ignition section in whichfuel is ignitedand a combustion chamber located adjacent to an outlet for said ignition section to provide a chamber in which the ignited fuel is at least partially burned, said ignition section being formed by a housing made up of a plurality of interconnected plates and a liner located within said housing and formed by a plurality of segments each of which is mountedon one of said plates, said segments of said combustion chamber liner being adjustably mounted in a spaced-apart relationship with said plates of said combustion chamber housing to provide an adjustable passage means for enabling air to flow between said liner and housing of said. I combustion chamber, said combustion chamber being formed 2. A combustion assembly in which fuel is burned, said com- 1 bustion assembly comprising a housing and a liner. located within said housing, said liner and said housing defining a flow passage therebetween, and means interconnecting said liner and said housing and providing for adjustmentof the spacing therebetween and adjustment of said flow passage, said housing having baffle means located at its opposite ends, said baffle means being adjustable to control air flow adjacent said combustion assembly.

3. A combustion assembly in which fuel is burned,said combustion assembly comprising a housing formed by a plurality of interconnected plates and a liner including a plurality of segments located within said housing, said liner and said housing defining a flow passage therebetween, and means interconnecting said liner and said housing and providing for adjustment of the spacing therebetween and adjustment of said flow passage.

4. A combustion assembly comprising an ignition section in which fuel is ignited and-a combustion chamber located adjacent to an outlet for said ignition section to provide a chamber in which the ignited fuel is at least partially burned, said ignition section being formed by a housing made up of a plurality of interconnected plates and a liner located within said housing and formed by a plurality of segments each of which is mounted on one of said plates, said segments of said ignition section liner mounted on one of said plates of said ignition section housing being located in a spaced-apart relationship with segments of said ignition section liner mounted on adjacent plates of said ignitionsectionhousing, said combustion chamber being formed by a housing made up of a plurality of interconnected plates and a liner located within said combustion chamber housing and formed by a plurality of segments each of which is mounted on one of said combustion chamber plates.

5. A combustion assembly comprising an ignition section in which fuel is ignited and a combustion chamber located adjacent to an outlet for said ignition section to provide a chamber in which the ignited fuel is at least partially burned, said ignition section being formed-by a housing made up of a plurality of interconnected plates and a liner located within said housing and formed by a plurality of segments each of which is mounted on one of said plates, said plates forming said housing of said ignition section being generally flat and trapezoidal in shape and said segments forming said liner of said ignition section being arcuate and generally trapezoidal in shape, said housing forming a frustrum having flat sides and said liner forming 'a generally conical frustrum which is located in a generally coaxial relationship with the frustrum' formed by said liner, said combustion chamber being formed by a housing made up of a plurality of interconnected plates and a liner located within said combustion chamber housing and formed by a plurality of segments each of which is mounted on one of said combustion chamber plates.

6. A combustion assembly comprising an ignition section in which fuel is ignited, said ignition section being formed by a housing made up of a plurality of interconnected plates and a liner located within said housing and formed by a plurality of segments each of which is mounted on one of said plates, some of said segments of said ignition section liner being formed of one material and other segments which are subjected to particularly severeoperating conditions being made of another material having greater resistance to severe operating conditions than said one material to enable said other segments to better withstand said severe operating conditions.

7. A combustion assembly comprising a housing formed b a plurality of interconnected plates, a liner located within said housing and formed by a plurality of segments each of which is mounted on one of said plates of said housing in a spacedapart relationship with said plates to form an air space between said plates and said segments, said segments of said liner being spaced apart from segments mounted on adjacent plates of said housing to enable said segments to expand relative to each other, first releasable mechanical connector means for releasably connecting each of said liner segments to an associated one of said housing plates and for enabling said liner segments to be readily disconnected from said housing plates, and second releasable mechanical connector means for releasably interconnecting said housing plates to thereby enable said combustion assembly to be readily assembled and disassembled.

8. A combustion assembly comprising a housing formed by a plurality of interconnected plates and a liner located within said housing and formed by a plurality of segments each of which is mounted on one of said plates in a spaced-apart relationship with said plates to form an air space between said plates and said segments, a plurality of said segments being mounted on each of said plates to form longitudinally extending portions of said combustion assembly, s'aid longitudinally extending portions of said combustion assembly being releaseably interconnected to facilitate assembly and disassembly of said combustion assembly.

9. A combustion assembly as set forth in claim 4 wherein said segments of said ignition section liner are mounted in a spaced-apart relationship with said plates of said ignition section housing to provide a passage means having a first opening at one axial end portion of said ignition section and a second opening at an opposite axial end portion of said ignition section for enabling air to flow through said passage means and into said combustion chamber.

10. A combustion assembly as set forth in claim 4 wherein said ignition section housing is shorter in length than said ignition section liner.

1]. A combustion assembly as set forth in claim 4 wherein said segments of said ignition section liner are mounted in a spaced-apart relationship with said plates of said ignition section housing to provide a flow passage between said segments and said plates of said ignition section. 1

12. A combustion assembly as set forth in claim 1 further including means for rotating said combustion chamber and means for forcing material from said combustion chamber upon rotation thereof.

13. An ignition section as set forth in claim 7 wherein said liner projects outwardly past at least one end portion of said housing to thereby form an inlet communicating with said air space to provide for an improved flow of air into said air space through said inlet.

14. An ignition section as set forth in claim 7 wherein a plurality of segments are mounted on each of said plates to form longitudinally extending portions of said ignition section, said longitudinally extending portions of said ignition section being releaseably interconnected to facilitate assembly and disassembly of said ignition section.

15. A combustion assembly as defined in claim 2 wherein said baffle means includes a member adjustable generally radially of said combustion assembly.

16. A combustion assembly as defined in claim 2 wherein said'combustion assembly comprises an ignition port having one end adjacent a dryer burner and its other end adjacent a combustion chamber and wherein said baffle means at one end controls air flow pastsaid burner and into said ignition port and said baffle means at the other end controls air flow between said ignition port and said combustion chamber.

17. An assembly comprising a burner, an ignition section wherein fuel is ignited and a combustion chamber wherein fuel ignited in said ignition section is at least partially burned, said ignition section including .a generally funnel shaped housing having one end adjacent said burner and its other end opening outwardly towards said combustion chamber and a generally funnel-shaped liner located within said housing, said housing and said liner having a spaced-apart relationship to provide an air passage extending between said liner and said housing and baffle members carried on said housing at the opposite ends thereof and adjustable to control air flow into said ignition port and said combustion chamber.

18. An assembly as defined in claim 17 further including means for rotating said combustion chamber and means for forcing material from said combustion chamber upon rotation thereof.

19. An assembly comprising a base, a burner operatively connected with said base, an ignition section associated with said burner and wherein fuel is ignited, a rotatable combustion chamber operatively connected with said ignition section and wherein fuel ignited in said ignition section is at least partially burned, an oven section associated with said combustion plow means mounted in said combustion chamber in a fixed relationship with said base for engaging material in said combustion chamber-and forcing this material from said combustion chamber upon "rotation of said combustion chamber relative to said base and plow means under the influence of said drive means.