US3680502A

US3680502A - Outdoor incinerator

Info

Publication number: US3680502A
Application number: US105328A
Authority: US
Inventors: Arnold M Rader
Original assignee: MINNEAPOLIS GAS CO
Current assignee: MINNEAPOLIS GAS CO
Priority date: 1971-01-11
Filing date: 1971-01-11
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01
Also published as: CA943009A

Abstract

A housing having first and second chambers defined therein with the first chamber having a grating mounted therein with a burner therebelow for receiving a charge of material to be burned and the second chamber having an elongated vertical stack extending thereinto a substantial distance so that an elongated annular portion is defined, which is in communication with the first chamber. A burner is positioned in the second chamber so that gases and other materials generated by the charge of material and passing from the first chamber through the annular portion of the second chamber to the inlet of the stack are ignited and burn substantially completely in the stack. Openings are provided in the housing adjacent the grating and adjacent the upper end of the first chamber for the ingress of air and the openings are constructed to regulate the maximum burning rate in the first chamber and provide sufficient air for substantially complete combustion in the stack.

Description

[ 51 Aug. 1, 1972 I [54] OUTDOOR INCINERATOR [72] Inventor: Arnold M.

Minn.

[73] Assignee: Minneapolis Gas Company, Minneapolis, Minn.

[22] Filed: Jan. 11, 1971 211 Appl.No.: 105,328

Rader, Minneapolis,

[52] U.S.Cl. ..110/8 C, 110/18C Primary Examiner-Kenneth W. Sprague Attorney-Merchant & Gould [5 7] ABSTRACT A housing having first and second chambers defined therein with the first chamber having a grating mounted therein with a burner therebelow for receiving a charge of material to be burned and the second chamber having an elongated vertical stack extending thereinto a substantial distance so that an elongated annular portion is defined, which is in communication with the first chamber. A burner is positioned in the second chamber so that gases and other materials generated by the charge of material and passing from the first chamber through the annular portion of the second chamber to the inlet of the stack are ignited and burn substantially completely in the stack. Openings are provided in the housing adjacent the grating and adjacent the upper end of the first chamber for the ingress of air and the openings are constructed to regulate the maximum burning rate in the first chamber and provide sufficient air for substantially complete combustion in the stack.

15 Claims, 11 Drawing Figures PATENTEDAus 1:912 3,680,502

SHEET 1 BF 3 5,2 4 I3 50 0 50 INVENTOR.

5O 39' 50 ARA/0L0 MHAOR @WC/MWT @0040 .AT TOPNEYIi BACKGROUND OF THE INVENTION 1. Field of the Invention Because of present pollution legislation and other attempts to maintain contamination of our atmosphere at a minimum, it is essential that incinerators burn materials with little or no smoke and odor. Further, outdoor incinerators utilized by private individuals and small commercial and industrial concerns must be capable of burning a wide variety of materials including wet garbage, plastics, wet and dry leaves, green grass, papers, etc. The incinerator must be simple to operate, small and inexpensive, and must be capable of burning the wide variety of materials completely with substantially no smoke or odor.

2. Description of the Prior Art In the prior art a great variety of multiple chamber type incinerators are disclosed. However, in all of these prior art incinerators the burning is not controlled and air is normally introduced immediately prior to the stack so that gases entering the stack are cooled to prevent further combustion and to reduce stack temperatures below l,000 F. A typical example of a prior art device is illustrated in the US. Pat. No. 3,509,834, entitled Incinerator, issued to Rosenberg et al. In this structure, two chambers are provided having a primary burner and an after burner and hot gases and products of combustion are mixed with outside air prior to entering the stack so that materials in the stack are nearly at ambient temperature.

In most prior art incinerators combustion occurs so quickly the material and products therefrom do not have time to burn completely and objectionable smoke and odors are still present at the outlet of the stack. Further, many of these prior art incinerators are extremely expensive and complicated as well as too large for use by private individuals.

SUMMARY OF THE INVENTION The present invention pertains to an improved outdoor incinerator including a housing defining a fireproof enclosure separated into first and second chambers by a partition having a communicating opening adjacent the top thereof with a first burner in the first chamber below a material receiving grating and a second burner in the second chamber adjacent the entrance to an elongated vertical stack communicating with the second chamber so that the stack operates as a final combustion chamber.

It is an object of the present invention to provide an improved outdoor incinerator.

It is a further object of the present invention to provide an improved outdoor incinerator which is compact, easy to operate, inexpensive and which produces substantially complete combustion with little or no smoke and odor.

It is a further object of the present invention to provide an improved outdoor incinerator wherein the stack operates as a final combustion chamber and the heat therein is sufficiently high to substantially completely burn all materials placed therein for incineration and all products generated thereby.

It is a further object of the present invention to maintain the stack at relatively high temperatures to produce the maximum natural draft for a given height of stack.

These and other objects of this invention will become apparent to those skilled in the art upon consideration of the accompanying specification, claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings, wherein like characters indicate like parts throughout the figures:

FIG. 1 is a view in side elevation of the improved outdoor incinerator;

FIG. 2 is a view in end elevation of the incinerator illustrated in FIG. 1;

FIG. 3 is an enlarged view in top plan of the incinerator illustrated in FIG. 1;

FIG. 4 is an enlarged sectional view as seen from the line 4-4 in FIG. 1;

FIG. 5 is an enlarged sectional view as seen from the line 5-5 in FIG. 2;

FIG. 6 is an enlarged sectional view as seen from the line 6-6 in FIG. 1, portions thereof broken away;

FIG. 7 is an enlarged sectional view as seen from the line 77 in FIG. 1, portions thereof broken away;

FIG. 8 is an enlarged sectional view as seen from the line 8-8 in FIG. 6;

FIG. 9 is a view in top plan of another embodiment of the improved outdoor incinerator, portions thereof broken away;

FIG. 10 is a sectional view as seen from the line 10- 10 of FIG. 9; and

FIG. 1 1 is a sectional view as seen from the line 1 1- 1 l in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the figures the numeral 10 indicates a generally box-shaped housing having horizontal upper and

lower walls

11 and 12, respectively, vertical spaced apart

side walls

13 and 14, a vertical generally rectangular-shaped front wall 15 and a vertical, semi-cylindrical rear wall 16. The housing 10 is formed of suitable heat resistant material and defines therein a fireproof enclosure 17. A vertically upwardly extending ring 18 is affixed to the upper surface of the lower wall 12 so as to be coaxial and adjacent to the semi-cylindrical rear wall 16. The upper wall 11 of the housing 10 has an opening therein coaxial with the semi-cylindrical rear wall 16 and a square plate 19 (see FIGS. 5 and 7) is affixed to the upper surface of the upper wall 11. The plate 19 has a downwardly extending flange 20 aflixed to the lower surface thereof, which flange 20 extends downwardly through the opening in the upper wall 11 generally in alignment with the ring 18 on the lower wall 12. The plate 19 has an opening therethrough coaxial with the flange 20 and having a diameter substantially smaller than the inner diameter of the flange 20.

A tubular-shaped partition 25 having an outer diameter equal to the inner diameter of the ring 18 and flange 20 is positioned within the enclosure 17 so as to extend between the upper wall 11 and lower wall 12 within the ring 18 and flange 20. The partition 25 divides the enclosure 17 into a first chamber 26 and a second chamber 27. A rectangular-shaped Opening 28 is formed in the partition 25 adjacent the flange 20 at the upper end thereof to provide communication between the first chamber 26 and the second chamber 27. The opening 28 is positioned to one side of the center of the housing so that gases and materials entering the second chamber 27 from the first chamber 26 enter generally tangentially and tend to follow a spiral path therein. In the present embodiment the partition 25 is formed of an insulating refractory material but it should be understood that substantially any fire resistant insulating or conducting material might be utilized. Since any heat conducted through the partition 25 from the first chamber 26 to the second chamber 27 will simply aid in preheating gases and other materials passing therebetween, it is not essential that the partition 25 be formed of insulating material. It should also be understood that the housing 10 and partition 25 may be formed in a variety of different embodiments by those skilled in the art and the present embodiment is illustrated for exemplary purposes.

An elongated vertical stack generally designated 30 is formed of a plurality of tubular elements 31 each having a portion 32 at one end thereof with a slightly larger inner and outer diameter and adapted to receive the opposite end of the adjacent tubular element 31 therein. The first tubular element 31 of the stack 30 extends downwardly through the opening in the plate 19 into the second chamber 27 approximately two-thirds the length of the second chamber 27. Further, the tubular element 31 is coaxial with the partition 25 and spaced therefrom to form an annular passageway 33 extending approximately two-thirds the length of the second chamber 27 from the upper wall 1 1 of the housirrg 10 toward the lower wall 12. The portion 32 of the tubular element 31 butts against the plate 19 to maintain the tubular element 31 fixedly in position. A final tubular element 34 is fixedly engaged in the portion 22 of the last or upper tubular element 31 to form the uppermost portion or outlet end of the stack 30. In the present embodiment the uppermost end of the stack 30 is something greater than eight feet from the lower wall 12, the heightdepending upon the amount of draft required within the incinerator. While a somewhat lower stack 30 may be utilized in some instances, a height of at least eight feet is desired for reasons of safety, since the stack 30 operates at extremely high temperatures and the outlet end thereof should be out of reach. As a general rule, increasing the height of the stack 30 will increase the draft through the incinerator. In the present embodiment the entire stack 30 is formed of an insulating refractory material but it should be understood that only the portion above the plate 19 needs to be formed of insulating material to improve the operation of the incinerator. By forming the external portions of the stack 30 of insulating material the loss of heat therethrough is minimized and the operation of the incinerator is improved.

An opening is provided in the upper wall 11 above the first chamber 26 and a door 37 is hingedly mounted thereover to allow access to the first chamber 26 so that material to be burned may be placed therein. A channel iron 38 is affixed to the inner surface of each of the

side walls

13 and 14 with the channels opening inwardly toward each other and so as to lie in a common horizontal plane spaced upwardly from the lower wall 12'. A grate 39 is constructed with a rod extending the length of each side thereof and other rods positioned therebetween in parallel and perpendicular spaced apart relationship. The grate 39 is sliclably engaged within the channel irons 38 and the front wall 15 of the housing 10 has a horizontal slot therein through which the grate 39 may be removed for cleaning, etc. An opening adjacent the bottom of the front wall 15 has an ash pan 40 positioned therein, which ash pan 40 overlies substantially the entire lower wall 12 in the first chamber 26. The grate 39 is spaced upwardly from the upper edges of the ash pan 40 and a burner 41 is positioned therebetween. Referring specifically to FIG. 4, it can be seen that the burner 41 extends from adjacent one side of the partition 25 diagonally to adjacent the opposite corner of the front wall 15 and side wall 14. In the present embodiment, the burner 41 is a gas burner but it should be understood that other types of burners might be utilized if desired. Further, the burner 41 is an elongated generally semi-cylindrical conduit with openings at the sides thereof in a common horizontal plane for the egress of burning gas and air mixtures. Through this arrangement the flame is distributed substantially evenly throughout the undersurface of the grate 39 in the first chamber 26. A screen 45 is formed into a generally semi-cylindrical shape and positioned within the first chamber 26 coaxial with the partition 25 and in slightly spaced relation therefrom by means of angle irons 46 aflixed vertically to the

side walls

13 and 14. The screen 45 prevents large particles of material from leaving the first chamber 26 through the opening 28 and allows gases and small particles of material generated by combustion of material positioned on the grate 39 to pass from the first chamber 26 through the opening 28 into the annular passageway 33. The screen 45 extends from slightly below the grate 39 to the upper wall 1 1.

A plurality of holes 50 are formed in the housing 10 adjacent the grate 39 (see FIG. 5) to provide a limited amount of air for combustion of a charge of material placed on the grate 39. Some air is introduced into the burner 41 for the combustion of the gas therein and the holes 50 are designed to provide additional air to mix with the material to be burned. A second group of holes 51 are provided in the housing 10 adjacent the upper wall 11, which holes 51 provide secondary air to mix with the materials generated by the burning of the charge of material on the grate 39. In general, the

charge of material placed on the grate 39 should not go 1 beyond the holes 51 in height so that the holes 51 remain clear for the passage of air therethrough. It should be understood that the holes 51 are provided in the housing 10 adjacent the upper wall 11 in the first chamber 26 for exemplary purposes but they might be located anywhere between the upper limits of the charge of material placed on the grate 39 and the inlet end of the stack 30 in the second chamber 27. The amount of air entering the holes 50 will in general be somewhat less than the amount of air entering the holes 51 because the air entering the holes 50 regulates the maximum burning rate while the air entering the holes 51 must be sufficient for complete combustion. As the charge of material positioned on grate 39 mixes with air entering holes 50 and burns, the products generated thereby move upwardly, mix with air entering the holes 51 and pass through the opening 28 into the annular passageway 33. In the annular passageway 33 the products generated and the air mix more thoroughly, continue combustion and spiral downwardly toward the inlet end of the stack 30. A second burner 52 with additional air opening 53, is positioned in the second chamber 27 adjacent the inlet end of the stack 30 so as to raise the temperature within the stack 30 in the range of approximately 1,000 F to 2,300 F, and generally around l,600 F. Because of the intense heat in the stack 30 the thoroughly mixed products, generated by burning of the charge of material in the first chamber 26 and air entering the holes 51, and the additional secondary air entering the opening 53, burn substantially completely leaving little or no smoke and odor. Further, because of the intense heat in the stack 30 a very high draft is produced throughout the incinerator and natural mixing of air occurs throughout the incinerator without the need for blowers and the like. It should be understood that the second burner 52 may be located anywhere in the gas flow path between the upper limits of the material in chamber 17 to within the lower end of the stack 30, including all of the chamber 27.

A generally box-shaped shell or heat shield 55 is fixedly attached to the upper wall 11 and lower wall 12 of the housing so as to be spaced from the

side walls

13 and 14, the front wall 15 and rear wall 16 to form an air passageway therearound. Insulation 56 is afi'lxed to the inner surface of the shell 55 to maintain heat therein. A plurality of louvers 54 are mounted in the shell 55 to allow air to enter the passageway between the shell 55 and the housing 10, where it is preheated and eventually enters the

holes

50 and 51 as well as the

burners

41 and 52. Because the air is preheated by traveling adjacent to the outer surface of the housing 10, little or no heat is wasted or radiated by the incinerator and the outer surface of the shell 55 remains relatively cool. An elongated heat shield protector 57, having a generally rectangularly-shaped cross section and tapering toward the upper end thereof is fixedly engaged around the stack 30. The heat shield protector 57 is fixed to the upper surface of the upper wall 11 by means of brackets 58 (see FIG. 7) formed from angle irons and is maintained in spaced relation from the upper end of the stack 30 by means of a collar 59 engaged around the upper element 34 of the stack 30 and fixed to the inner surface of the heat shield protector 57. Openings 60 are provided at the bottom of the heat shield protector 57 on each side thereof and the upper end is spaced from the element 34 of the stack 30 to provide for the passage of air therebetween. Thus, air is free to travel through the area between the heat shield protector 57 and the outersurface of the stack 30 so that the outer surface of the heat shield protector 57 is relatively cool. Since the stack 30 is formed of insulating material this circulation of air between the heat shield protector 57 and the stack 30 does not dissipate substantial amounts of heat from the incinerator. Also, the heat shield protector 57 serves to support and protect the

elements

31 and 34 from mechanical damage.

A gas connection 65 is provided in the rear wall of the shell 55 for the application of gas to the

burners

41 and 52, which gas is conducted to controls (not shown) situated in an insulated chamber in a rear comer of the shell 55, access to which is available through a ventilated door (see FIG. 1 The controls could include any or all controls known to one skilled in the art, such as safety pilot, timer, temperature controls, draft controls, etc. A second door 67 below the door 66 is provided for access to the

burners

41 and 52 for maintenance and the like. A door 68 in the front wall of the shell 55 adjacent the lower end thereof is provided for access to,

the ash pan 40 and grate 39. It should be understood that the present embodiment is illustrated for exemplary purposes and a great variety of modifications and innovations may be provided by those skilled in the art. In particular, it may be desirable to place fins within the annular passageway 33 to direct gases and other materials passing therethrough into a more distinct spiral-shaped path. In addition to or in place of fins in the annular passageway 33 it may be desirable to construct the bottom of the second chamber 27 in an inverted cone-shaped or several concentric rings and valleys to aid in turning the gases and materials passing from the annular passageway 33 into the inlet end of the stack 30. Further, the direction, position and type of burners 41 and/or 52 may be altered or modified by those skilled in the art.

Referring to FIGS. 9, 10 and 11, another embodiment of the improved outdoor incinerator is illustrated, wherein similar parts are designated with similar numbers and all of the numbers have a prime added to indicate a different embodiment. In this embodiment a housing 10 is divided into a lower generally vertically extending first chamber 26 and an upper generally cylindrical horizontally extending chamber 27'. The horizontally extending chamber 27 has an inner diameter approximately equal to the inner diameter of a stack 30' and is connected directly thereto through an elbow 29. A first burner 41 is situated beneath a grate 39', as in the above-described embodiment, and a second burner 52 is mounted in the elbow 29' and directed into the stack 30'. While a specific position and direction for the burner 52' is illustrated, it should be understood that modifications in direction, position and type of burner 52 may be devised by those skilled in the art.

While some modifications to certain portions of the embodiment illustrated in FIGS. 9, l0 and 11 are necessitated by the change of position of the second chamber 27', such as the position of the access door 37 in the upper wall 1 1', the remaining portions of the incinerator operate in substantially the same manner described in conjunction with FIGS. 1 through 8. An inlet conduit 24', having a generally rectangularshaped cross section, is affixed to the partition 25' in communication with the opening 28 therethrough to aid in directing gases and materials passing from the first chamber 26' into the second chamber 27' in a spiral path within the chamber 27'. If desired, fins or the like could be afiixed to the inner surface of the chamber 27 to aid in directing the materials and gases into more definite spiral patterns.

Thus, an improved outdoor incinerator is disclosed which increases the path length of products generated by the burning of a charge of material therein so that the products have a greater burning time and greater chance for complete combustion. Further, because of the novel configuration of the incinerator an improved draft is produced which provides natural mixing of air and the products generated without requiring blowers and the like. Utilizing the stack as a third combustion chamber greatly reduces the size of the incinerator and improves the operation thereof. While I have shown and described specific embodiments of this invention, further modifications and improvements will occur to those skilled in the art. I desire it to be understood, therefore, that this invention is not limited to the specific forms shown and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of this invention.

What is claimed is:

1. An improved outdoor incinerator comprising:

a. a housing defining a fireproof enclosure;

b. a partition within said housing dividing the enclosure into first and second chambers with an opening providing communication therebetween;

c. a door in said housing providing external communication with said first chamber;

d. means mounted within said first chamber for receiving thereon the material to be burned;

first burner means mounted within said first chamber for producing at least partial combustion therein; an elongated tubular stack affixed to said housing in communication with said second chamber, extending a substantial distance within said second chamber and extending generally vertically therefrom, said stack being substantially imperforate for preventing the ingress of cooling air; and second burner means mounted within said second chamber for producing controlled final combustion within said stack by maintaining stack temperatures relatively high.

2. An improved outdoor incinerator as set forth in claim 1 wherein the partition is generally tubular with an inner diameter larger than the outer diameter of the stack and the stack extends coaxially within the partition a substantial distance.

3. An improved outdoor incinerator as set forth in claim 1 wherein at least the exterior portion of the stack is formed of insulating refractory material.

4. An improved outdoor incinerator as set forth in claim I having in addition a heat shield affixed to the housing and at least partially surrounding the stack in radially outwardly spaced relationship for providing a cool air passageway therebetween.

5. An improved outdoor incinerator as set forth in claim 2 wherein the partition extends generally vertically within the housing and the communicating opening is positioned adjacent the top of the enclosure defined within the housing.

6. An improved outdoor incinerator as set forth in claim 1 wherein the means for receiving the material to be burned includes a grating spaced upwardly from the bottom of the housing and the incinerator further includes openings adjacent the grating for the ingress of primary air for combustion of a charge of material.

7.'An improved outdoor incinerator as set forth in claim 6 including in addition openings in the housing for the ingress of secondary air for combustion of the products generated by the charge of material, said openings being located between an upper limit of the charge of material and the inlet end of the stack.

8. An improved outdoor incinerator as set forth in claim 7 wherein the first burner means is positioned generally beneath the grating and at least some of the openings for the ingress of secondary air are located in the first chamber adjacent the upper end thereof.

9. An improved outdoor incinerator as set forth in claim 7 wherein the total area of the openings for the ingress of primary air for combustion of the charge is sufiiciently small to regulate the maximum burning rate and the total area of the openings for the ingress of secondary air is sufficiently large for substantially complete combustion of the products generated by the charge of material.

10. An improved outdoor incinerator as set forth in claim 7 wherein the first and second burner means, the openings for the ingress of primary and secondary air and the length of the stack are adjusted to produce temperatures within the stack in the range of approximately 1,000 F to 2,300 F during operation of the incinerator.

11. An improved outdoor incinerator as set forth in claim 1 wherein an exterior wall is affixed to the housing in outwardly spaced relation therefrom so as to at least partially surround the housing and provide a relatively cool outer surface for protection.

12. An improved outdoor incinerator as set forth in claim 1 having in addition means associated with the second chamber for directing the gas flow from the first chamber into generally spiral shaped paths.

13. An improved outdoor incinerator comprising:

a. a housing defining a fireproof enclosure;

b. a partition mounted within said enclosure and extending generally vertically from top to bottom thereof so as to divide the enclosure into a first chamber and second generally cylindrical, vertically extending chamber;

. a grating mounted within said first chamber in spaced relation from the bottom thereof for receiving thereon the material to be burned;

. a door in said housing providing external communication with said first chamber;

. an elongated, tubular imperforate stack affixed to said housing so as to extend generally coaxially into said second chamber a distance greater than one half the vertical length of said second chamber, the respective diameter of said second chamber and said stack being sufficiently different to form an annular vertically extending portion in said second chamber;

. an opening defined in said partition adjacent the upper end thereof providing communication between said annular portion of said second chamber and said first chamber;

first burner means mounted in said first chamber below said grating; and

h. second burner means mounted in said second chamber adjacent the end of said stack.

14. An improved outdoor incinerator as set forth in claim 13 having in addition openings in the housing adjacent the grating for the ingress of primary air for combustion of a charge of material and openings in the housing located between an upper limit of the charge of material and the inlet end of the stack for the ingress of secondary air for combustion of the products generated by the charge of material.

15. An improved outdoor incinerator as set forth in claim 14 wherein the first and second burner means, the openings for the ingress of primary and secondary air and the length of the stack are adjusted to produce temperatures within the stack in the range of approximately 1,000 F to 2,300 F during operation of the incinerator.

Claims

1. An improved outdoor incinerator comprising: a. a housing defining a fireproof enclosure; b. a partition within said housing dividing the enclosure into first and second chambers with an opening providing communication therebetween; c. a door in said housing providing external communication with said first chamber; d. means mounted within said first chamber for receiving thereon the material to be burned; e. first burner means mounted within said first chamber for producing at least partial combustion therein; f. an elongated tubular stack affixed to said housing in communication with said second chamber, extending a substantial distance within said second chamber and extending generally vertically therefrom, said stack being substantially imperforate for preventing the ingress of cooling air; and g. second burner means mounted within said second chamber for producing controlled final combustion within said stack by maintaining stack temperatures relatively high.

4. An improved outdoor incinerator as set forth in claim 1 having in addition a heat shield affixed to the housing and at least partially surrounding the stack in radially outwardly spaced relationship for providing a cool air passageway therebetween.

7. An improved outdoor incinerator as set forth in claim 6 including in addition openings in the housing for the ingress of secondary air for combustion of the products generated by the charge of material, said openings being located between an upper limit of the charge of material and the inlet end of the stack.

9. An improved outdoor incinerator as set forth in claim 7 wherein the total area of the openings for the ingress of primary air for combustion of the charge is sufficiently small to regulate the maximum burning rate and the total area of the openings for the ingress of secondary air is sufficiently large for substantially complete combustion of the products generated by the charge of material.

10. An improved outdoor incinerator as set forth in claim 7 wherein the first and second burner means, the openings for the ingress of primary and secondary air and the length of the stack are adjusted to produce temperatures within the stack in the range of approximately 1,000* F to 2,300* F during operation of the incinerator.

13. An improved outdoor incinerator comprising: a. a housing defining a fireproof enclosure; b. a partition mounted within said enclosure and extending generally vertically from top to bottom thereof so as to divide the enclosure into a first chamber and second generally cylindrical, vertically extending chamber; c. a grating mounted within said first chamber in spaced relation from the bottom thereof for receiving thereon the material to be burned; d. a door in said housing providing external communication with said first chamber; e. an elongated, tubular imperforate stack affixed to said housing so as to extend generally coaxially into said second chamber a distance greater than one half the vertical length of said second chamber, the respective diameter of said second chamber and said stack being sufficiently different to form an annular vertically extending portion in said second chamber; f. an opening defined in said partition adjacent the upper end thereof providing communication between said annular portion of said second chamber and said first chamber; g. first burner means mounted in said first chamber below said grating; and h. second burner means mounted in said second chamber adjacent the end of said stack.

15. An improved outdoor incinerator as set forth in claim 14 wherein the first and second burner means, the openings for the ingress of primary and secondary air and the length of the stack are adjusted to produce temperatures within the stack in the range of approximately 1,000* F to 2,300* F during operation of the incinerator.