US3436061A

US3436061A - Rotating sectioned furnace

Info

Publication number: US3436061A
Application number: US641322A
Authority: US
Inventors: Robert E Zinn
Original assignee: Arthur D Little Inc
Current assignee: Arthur D Little Inc
Priority date: 1967-05-25
Filing date: 1967-05-25
Publication date: 1969-04-01
Anticipated expiration: 1986-04-01

Description

April l, 1969 R. E. zlNN ROTATING SECTIONED FURNACE o lfu m 2 l' /M /m gillu w Filed May 25, 1967 Robert E. Zinn INVENTOR.

BY/w;

Attorney pril 1, 1969 R. E. zlNN 3,435,06l

ROTATING SECTIONED FURNACE Filed May 25, 1967 Sheet 2 of 4 Rober E. Zinn F g. S INVENTOR.

Attorney April l, 1969 R. E. zlNN ROTATING SECTIONED FURNACE Filed May 25, 1967 Sheet 3 @f4 Fig. 8

66 {Qi/f |77/ |78 Rober? E. Zinn INVENTOR.

Aiorney April 1, 1969 R. E. zlNN ROTATING SECTIONED FURNACE Sheet Filed May 25, 1967 Robert E. Zinn 1NVENTOR.

BY /w4 Attorney U5. Cl. 263-32 23 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a furnace adapted to effect reactions between solid matter, or semi-solid matter, and a fluid. The furnace is particularly suited to burning or reacting those solid materials which could plug or damage a grate by overheating, oxidation or otherwise. The furnace is constructed of segments in telescoping relationship positioned at an angle with the horizon. The segments may or may not be axially aligned. Each segment is rotated for stoking action and discharges the solid material by gravity into the succeeding segment in a manner to permit the introduction of fluid under the solids as they are transferred from segment to segment. The furnace is particularly suited for use as an incinerator or as a pyroprocessing kiln, including reduction and oxidation as well as many additive reactions involving gases, liquid and solid reactants.

It is often necessary to be able to burn or otherwise react solid materials, or semi-solid materials, with a fluid, eg., dry air, air which may contain water vapor, or other uids such as C12, SO2, HF, S03, P205, etc. As an example, in burning refuse it is necessary to supply air to burn the refuse. This is generally done in stationary combustion chambers or in kilns. In combustion chambers, it is customary to employ moving grates of various designs to advance the solid materials during its burning or reaction, and, if desirable, to supply air below and above the grates. There is, however, a number `of classes of refuse or waste which can be burned only with difficulty in combustion chambers having grates; for such materials as plastics, metal foil, glass, etc., can melt and plug or jam the grates. Moreover, when such material melts it runs through the grate and burns under the grate with damage to the grate and fire box. Finally, some reactions are highly corrosive to grate metals.

Rotary kilns without grates have been used as incinerators but they provide no way in which a uid; e.g., air, can be introduced under the solid material. This in turn means that it is very difficult, if not impossible, to obtain complete reaction between the Huid and solid components and the stoking action is limited to the rotating action. In rotary kilns, it is customary to introduce all or almost all of the air with the charge into thekiln; and this may require the introduction of an excess of air which can quench the initial flame or reaction, `or produce intolerable hot spots. Fluid can also, of course, be introduced at the discharge end to ow countercurrent to the direction of solids flow. However, in incinerators this can result in the distillation of undesirable vapors and odors, with their discharge into the atmosphere through the discharging end, which are too cool to react, or oxidize, without the use of an afterburner.

There is therefore a need for a furnace which -does not have grates but which has stoking action and which permits introducing the reacting fluid to mix thoroughly with the solid matter at controlled points, as well as over the solid materials, if desired. By introducing the fluids or gases concurrently with the solid material to be burned or reacted, there is no opportunity, as would be with 3,4%,6 l Patented Apr. 1, 1969 countercurrent gas feed, to distill out vapors or odors which would be carried through the charging end of the furnace since each reaction may be completed at a predetermined point.

It s therefore a primary object of this invention to provide an improved furnace adapted for reacting solids or semi-solids with fluids, the reaction conditions (reactant ratios and temperatures) being controlled throughout the entire length of the furnace. It is another object of this invention to provide a furnace of the character described which is particularly well suited for burning refuse which can plug or jam grates, or which would be destructive to the grates through corrosive action or the creation of hot spots under the grates. It is another object of this invention to provide a grateless furnace which achieves a stoking action. It is yet another object to provide a furnace of the character described which is adaptable to the addition of solid reactants. It is still another object of this invention to provide a furnace of the character described which prevents the quenching of the initial reaction or llame and permits the complete control of the character and quantity of fluids or solids which are introduced for reacting with the solid material.

Other objects of the invention will in part by obvious and will in part by apparent hereinafter.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should lbe had to the following detailed description taken in connection with the accompanying drawings in which FIG. 1 is a side elevational view of one embodiment of the furnace constructed in accordance with this invention providing integrated cylindrical segments rotated as a single unit;

FIG. 2 is a longitudinal cross sectional lview of the charging end of the furnace in FIG. l;

FIG. 3 is a cross section of the charging end taken along line 3 3 of FIG. 2;

FIG. 4 is a detailed cross section of the joining of two `of the sections of the furnace such as

sections

12 and 13 of FIG. 1;

FIG. 5 is a cross section of the joining portion including the hood taken along line 5-5 of FIG. 4;

FIG. 6 is a fragmentary detailed cross section showing a modification of the joining of the two segments of the furnace;

FIG. 7 is a side elevational view of a modification of the furnace providing integrated frustoconical segments rotated as a single unit;

FIG. 8 is a side elevational View of another embodiment of the furnace of this invention providing axially aligned segments which are separately rotated;

FIG. 9 is a cross section of the furnace of FIG. 8 taken along line 9 9 of FIG. 8;

FIG. 10 is a side elevational view partly in cross-section of an embodiment of the furnace wherein the segments are separately rotated and positioned at different angles and means are provided for introducing solid reactants; and

FIG. 11 is a cross section of the furnace of FIG. 10 along line 11-11 of that gure.

Summary of the invention The furnace of this invention is constructed of a plurality of rotatable sections which are normally but not necessarily in axial alignment `and which are in telescoping relation with each other. These segments join in overlapping relationship and at the point of overlap there is positioned a fluid inlet hood. The solid material within the rotating sections is moved along by gravity, and stoking action is accomplished through the rolling action induced by the rotation of the sections as well as t-hrough the spilling of the material from section to section. Underre air, or other fluid, is introduced into the solid material as it drops by gravity from one section to another. Provision is also made, if desired, for providing overfire air, or other fluid, along the length of the furnace as well as for introducing liquid fuel or liquid residue at the charging end of the furnace. Solid reactants may also be introduced into one or more of the segments.

FIG. l isa side elevational view of a furnace constructed in acordance with the teaching of this invention. It will be seen that the furnace is made up of four axially aligned segments or

sections

10, 11, 12 and 13. It is, of course, possible to use any number of segments, e.g., two or more. These four segments of FIG. l, as will be described below in connection with FIGS. 4 and 5, may be joined so that they are in effect one integrated rotatable furnace. Where the segments are joined through overlapping, there are provided

hoods

14, 15 `and 16 which are adapted to introduce air or other fluids and/ or solids at controlled points into each of the succeeding segments. The charging end is capped with an appropriate stationary end hood 19 which has associated with it a charging means and the discharging end has a stationary discharge receiving means 21, both of which will be described in detail below.

Means are supplied for rotating the integrated segmented furnace. Such means can be a pair of rollers 24 which engage tire 25 affixed to section 10` to support the charging end of the furnace. These rollers are rotated on a shaft 26 which is in a bearing support 27 mounted on a suitable contoured foundation 28. In keeping with customary engineering practice, means will be provided to counteract the thrust forces resulting from the angled position of the tire and rollers. The discharging end of the furnace is similarly supported on two rollers 29 (one of which is shown) engaging tire 30 afxed to section 13. These rollers 29 rotate on shaft 31 mounted on a bearing support 32 which in turn is also located on a suitably contoured foundation 33. In keeping with normal practice the furnace may be rotated by the use of a driven gear 36 which is permanently attached to the outer surface of the furnace and engages a driving gear 37 mounted on shaft 38 mounted in a support and bearing 39 which in turn is positioned on a suitably contoured foundation 40. Finally, suitable supporting means are provided, such as

frameworks

41, 42, 43 and 44, to maintain the stationary hoods in position.

As will be pointed out below, it is possible to use the furnace of this invention not only as an incinerator but as a kiln or as a reaction zone or as a series of diiferent reaction zones. However, for convenience in describing the furnace, particularly with reference to FIGS. 1-7, it will be assumed that it is to be used as a means for incinerating certain types of refuse. This means that the fluid introduced will be air for combustion which may or may not contain a certain amount of moisture or water fog.

The combustion air is supplied to the charging end of the furnace through a fluid inlet conduit 45. There are also provided

fluid supply lines

46, 47 and 48 which are associated with

hoods

14, 15 and 16, respectively. These are all connected to a common supply manifold line 49 which in turn is connected to a uid pump 50.

In the embodiment of FIG. 1 there is shown a stationary chamber 54 associated with the discharge end of the rotating furnace and serving as the discharge receiving means 21. If it is desired, some combustion or reaction with volatiles may take place in chamber 54 and there is therefore provided a fluid feed line 55 for introducing additional air. This furnace is equipped with a solids co1- lector 56 and an inspection door 57. The embodiment of FIG. l may also have a secondary combustion chamber 58 which is designed to burn volatile and oxidizable materials in the ue gases which may be discharged from the rotating furnace. As an alternative to this secondary combustion chamber, the hot gases from chamber 54 may be introduced into a waste-heat boiler. This secondary com- Ibustion chamber, shown partially in cross section, is seen to have a combustion zone 60 defined by a refractory lining 61 enclo-sed in an inner main shell 62. In the secondary combustion chamber of FIG. 1 there is provided optional means for preheating the combustion air which is to be used in the rotating furnace and introduced through the

hoods

14, 15, 16 and through 55. This is done by providing an outer shell 63 around and spaced from the main shell 62. Between these two shells there is dened an annular passage 64 into which the combustion air is introduced and preheated prior to its being withdrawn through line 65 into pump 50 for introduction into the

hoods

14, 15 and 16 by way of line 49 and then branch

conduits

46, 47 and 48.

FIG. 2 is a cross section of one embodiment of the charging end of the furnace of this invention, such as the charging end of section 1t) of the furnace of FIG. l. Within section 10 (and in each succeeding section) there is dened a combustion area 70. Section 10 is formed of a primary steel shell 71 and an outer steel shell 72 which de'ne between them an annular passage 73 for circulating combustion air for preheating. The second or outer shell 72 is optional and in many cases it will be desirable not to include the preheating passage 73 and permit the furnace wall 71 to be cooled by radiation to the surrounding atmosphere. The section is lined by a suitable refractory material 74 over the inner Wall of the steel shell 71. It will, of course, be necessary to place such a refractory lining anywhere in the furnace where high temperatures are to be encountered. In order to keep the solid matter from being carried along too rapidly and in order to control the amount of solid material which is fed into the remaining sections of the furnace there may be included in this embodiment a dam 76 which is designed to control the flow of solid material 83 through at least the first section of the furnace.

The feed end of the furnace is capped with a stationary hood 78 which defines a fluid passage 79 therein. As an alternative to the hood arrangement of FIG. 2, a vertical stationary end hood 19 may be used as shown in FIG. 1. The charging means 20 comprises a charging conduit 80 which denes a charging channel 81 providing communication between the feed hopper 82 and the combustion area 70. Combustion air is introduced under the solid material 83 as it leaves channel 81 through the air conduit 45. It may also be introduced adjacent to the solid material as it enters area 70. Additional combustion air, fuel, liquid refuse, solids, or a mixture of these (whichever is desirable) is introduced over the solid material through

conduicts

85 and 86 which lead from the exterior of the furnace down through the stationary hood 78 into the combustion area 70. Any number of these auxiliary feed lines may be used; they may also be omitted if desired. Preheated air from channel 73 enters uid passage 79 through ports 88.

Turning to FIG. 4 it will be seen how the two aligned sections are joined and the manner in which the hood is used to introduce air at the desired points in each section. In this embodiment the preheating passage and outer shell are not used. It will be appreciated that the details of FIG. 4 are applicable to each of the section overlaps and the hood which covers such overlaps.

Furnace sections

12 and 13 dene within them combustion zones and 96. Section 12 is formed of a shell 98 which is lined with refractories 99. These refractories preferably extend somewhat beyond the end of the shell in order to protect the steel walls and are anchored by means of a key 102. ln like manner, section 13 is formed of a shell 100 and lined with refractory material 101 which in this case extends somewhat beyond the corresponding point at which the shell 98 and refractories 99 of section 12 overlap. These refractories are held in place by means of a retaining ring 193. The hood 16 is formed of a stationary housing 105 which will be seen to fit closely over the two

sections

12 and 13. It is not necessary that a fluid-tight seal be made at this point and this eliminates any wear which might be experienced between the outer surface of the rotating furnace sections and the stationary hood. The hood defines within it an annular passage 106 which is in liuid `communication with the feed line 48. There is defined between the two sections 12 'and 13 of different diameters an annular passage 110 communicating with area 111 which is directly under the solid material as it fiows from the combustion zone 95 to the combustion zone 96. The two

shells

98 and 100 which form the outer walls of the two

sections

12 and 13 are joined through a series of radial supports 112. Thus, in this way the entire furnace is made into an integrated rotating device on a single common axis. Since it will normally be desirable to introduce the major portion of the air or other combustion gas under the solid material through passages 110 into area 111, it will be necessary to control or completely block off the flow of gas into the upper portion of the rotating furnace. This is done through the use of a web 114 which, as will be seen in FIG. 5, extends around the upper part of the hood and is afiixed to the hood wall. However, it may be desirable to introduce some overfire air and to be able to control the amount of this overre air introduced. This is done by the use of ports 116 in the web which have associated with them dampers 117 operating in suitable tracks system 118. Only one of these is shown in FIG. 5. However, any number of dampers and ports may be used. To each of the dampers is hooked a radial rod 119 which passes through a seal 120 in the hood wall and is aixed to the damper 117 through a suitable trunnion device 121 shown schematically. Other means for moving the dampers may also, of course, be used.

FIG. 6 illustrates a modification of the discharge end of a segment shell. In this modification means are incorporated for cooling the discharge end of the furnace segment. To do this an annular channel 126 is provided and it is defined by an end wall 124 and an outer ring 125. Into the channel 126 cooling air, or other iiuid, is introduced through line 127. Thus, this end of the section may be controlled with respect to its temperature.

FIG. 7 is another embodiment of the furnace of this invention showing the use of frustoconical sections in place of the cylindrical sections of the furnace of FIG. 1. In this embodiment, the sections are all of a similar size and configuration and aligned so that the smaller diameter end of the frustoconical section is inserted in telescoping relationship into the larger end of the succeeding section. 'The hood design and the manner in which the furnace is rotated and operated is essentially the same as that for FIG. l. In the embodiment of FIG. 7, the secondary combustion chamber is omitted and there is supplied a collection means 137 for accumulating solid materials which can be discharged periodically into a suitable receiving means 138 by opening the gate 139. It is also, of course, within the scope of this invention to make the frustoconical sections of increasing size if desired.

FIG. 8 is another embodiment of a furnace constructed in accordance with this invention. This embodiment does not have a secondary combustion chamber nor a solids collector associated with it. It differs from the furnace of FIG. l in that means are provided for rotating each of the sections individually, thus making it possible to treat the solid material differentially in each of the rotating segments. It is possible in the arrangement of FIG. 8 to rotate the sections either at different speeds or in different directions, or both, as may be desired; and also to introduce different fiuids into each of the sections, or the same uid at different rates. In the furnace of FIG. 8 there are provided three axially aligned

sections

144, and 146. At the point where these are joined there are provided a hood 147 which receives a fluid through line 148 and a hood 149 which receives a iiuid through line 150. The hoods, as well as the construction of the sections, are essentially those which are shown in FIGS. 4 and 5 except that the radial supports 112 are not present inasmuch as the sections are not joined to form an integral component.

The arrangement of the furnace in FIG. 8 requires that each section be provided with a suitable means for rotating it. This is done by providing section 144 with suitable supporting means which include two pairs of rollers 152 which engage tires aixed to the outside of section 144. Only one of the rollers of each pair is shown at each end. These rollers rotate in shafts 153 supported on bearing supports 154 which are mounted on a foundation 159. Also mounted on the foundation is the mechanism for the rotation of the section. This constitutes a driven gear 155 afiixed to section 144 and a driving gear 156 along with its shaft 157 and support 158.

In like manner, section :145 is supported on two pairs of rollers 162 engaging tires `161 and rotating on shafts 163 which are mounted on suitable supports 164 which rest on a contoured foundation 169. There is also provided a driven gear 165, a driving gear 156 rotating on shaft 167 in `support 168. And `finally, section 146 has supports which comprise two pairs of rollers 172 engaging tires 171 and rotating on shafts 173 mounted in supports 174 affixed to a contoured foundation 179. There is also a driven gear 175, a driving gear -176 rotating on a shaft 17'7 and mounted on a support 178 for rotating section 146. The embodiment of FIIG. 8 is provided with a discharge hood 180" and a gate 181 adapted for removing solid materials arriving at or accumulating in the discharge end of section 146i.

The embodiment of lF'IG. 8 permits the rotation of each of the sections at different speeds or in different directions or a combination of botlh of these forms of operation. Different gases or reactant fluids may be introduced into the different sections and the fluid iiow rates may be controlled to make each section, if desired, a separate furnace. 'I'he furnace shown in FIG. 8, and in cross section in FlIG. 9, would be particularly suitable for calcining materials or reacting solid materials with gaseous reactants where the `temperatures and reactant ratios must be controlled for a series of 'succeeding processing steps.

The furnaces in FIGS. 1-9 have illustrated rvarious embodiments in which the segments are mounted and maintained in axially alignment. However, there may be applications for the furnace of this invention wherein it is desirable =to maintain and rotate each segment at a different angle from that of the adjacent segments. In some reactions it will be desirable to control the residence time of the material in each different reaction zone (segment) and this can be done by adjusting the angle of the segment with t'he horizon and the speed of rotation, or a combination of these. (It may also be necessary or desirable to introduce solid reactants into one or more of the reaction zones. In addition to making it possible to 'handle such solid reactants, this would permit, in the case of free-owing feedstocks, the achieving of significant changes in the effective length of the furnace. The modifications of the furnace illustrated in FIGS. 10 and 11 incorporates both varying-angle segments and means for feeding solids into a reaction zone.

The furnace of FIG. l0 is formed of three

segments

190, 191 and 192, each mounted at a different angle to the horizon. Whether the angle of mounting is the same for each of the furnace segments as in FIGS. 1, 7 and 8 or different for each segment as in FIG. 10, it may be defined Ias a small acute angle (e.g., under 15) with respect to the horizontal plane on which the furiiace is placed. The

segments

190, 191 and 192 are joined through hoods 194- and 195 and closed at the charging end by stationary end hood 196 and at the discharging end by a stationary collection means 197. 'Each section has a set of

tires

198, 199 and 200 for

sections

190, 191 and 192, respectively. These are, of course, mounted on rollers such as shown in FIG. 8 and driven by means of a suitable mechanism as discussed previously. In FIG. 8 the segments are shown to have driven

gears

201, 202 and 203 affixed to them; the driving gears and the mounting means are not illustrated inasmuch as they are similar to those shown in FIGS. 1 and 8.

r'he material to be charged into the furnace may be in the form of a fluid (gas or liquid) or a solid, or a combination of both. There are therefore provided a solid charging line 205 and two fiuid charging lines 206 and 207 which are afhxed to stationary hood 196. Means are provided for introducing a gaseous reactant under and into the solid material 220 as it spills from reaction zone 212 in section 190 to reaction zone 215 defined in section 191. Such a means comprises a gaseous conduit 208 which serves as a communication between a source (not shown} of the gaseous reactant `and the passage 222 defined by hood 194. A means for handling solid feed 210 is also provided. The hood has affixed within it a web 223 to control the point or points at which the gaseous reactant enters the furnace segment. This web is similar in function to web 114 of YFIG. 4, and like that lweb it may have ports `and dampers to permit controlled overlire gas introduction. The solid feed means comprises a feed channel 224 terminating in a hopper 22S and the solid reactant feedstock 226 is fed by gravity into zone 215. A gate 227 may be placed in the channel 224 to control the solid feedstock rate.

The furnace segments of FGS. l0 land ll are preferably constructed in the manner illustrated in FIGS. 2 and 4. lIn the partial cross section, for example, section 190 is seen to be formed of a shell 213 having a refractory lining 214 and section 191 of a shell 216 with refractory lining 217.

It will be appreciated that the various modifications illustrated may be applied to each of the various embodiments. For example dams, such as dam 76 of FIG. 2, may be used in one or more of the segments of any of the furnaces; the means for feeding solids, Such as shown in FIG. 10, may be incorporated into any of the hood assemblies; the cooling device of FIG. 6 may be a part of the discharge end of any of the sections or segments; the frustoconical sections (FIG. 7) need not be in axial alignment but may be arranged as the cylindrical sections of vFIG. l; and the stationary end hoods `and solids receiving means of `FZIGS. 1, 2 and 10 may be replaced by a discharge hood such as shown in FIG. 8. Further examples of modifications which may be made include the integration of less than all of the sections of a furnace and the aligning of more than one but less than all of the sections lralong a common axis. Various systems for supporting and rotating the segments, either as an integrated furnace or as separate entities, will occur to those skilled in the art and it is meant to include all such suitable devices for achieving these functions within the scope of this invention, those shown in the drawings being illustrative only.

It will be seen from the preceding description that the furnace of this invention provides stoking action without any grates, and makes it possible to provide fiuid and solid reactants at desired points in the reaction zone as well as to control reaction conditions in each section of the furnace. Thus, there is offered a wide latitude in the operational parameters.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efliciently attained and, since certain changes may be made in the above constructions `without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic Iand specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, mig -t be said to fall therebetween.

I claim:

1. A grateless furnace adapted to provide a plurality of reaction zones into which reactants may be controllably introduced, comprising in combination:

(a) a plurality of rotatable sections maintained in telescoping relationship with each other such that the charge end of each section, except the first, forms an overlap and surrounds the discharge end of the preeding section and defines therewith an annular passage which is parallel to the wall defining the overlapping section; lthe axis of each of said sections from its charge end to its discharge end forming a small acute angle with the horizon whereby each of said sections is adapted to feed solids by gravity to a succeeding section;

(b) separate stationary hood means surrounding and enclosing each of said overlaps and defining with at least a portion of said annular passage a fluid passage adapted to introduce fiuid at least under and into said solids as they are transferred from section to section;

(c) means for conducting said fluid into said hood means;

(d) means for supporting said sections for rotating;

(e) means for rotating said sections;

(f) means for introducing reactants, including said solids, into the charge end of the first of said sections thereby forming furnace charging means; and

(g) means for withdrawing and receiving reaction products from the discharge end of the last of said sections thereby forming furnace discharging means.

2. A furnace in accordance with claim 1 wherein said sections are axially aligned.

3. A furnace in accordance with claim 1 wherein the axes of said sections form different angles with the horizon and separate means are provided for rotating each of said sections.

4. A furnace in accordance with claim 3 wherein said sections are of frustoconical configuration.

5. A furnace in accordance with claim 1 wherein said sections are of a cylindrical configuration of increasing diameter from the charging end to the discharging end of said furnace.

6. A furnace in accordance with claim 1 wherein said sections are of frustoconical configuration.

7. A furnace in accordance with claim 1 wherein said sections are axially aligned and aiiixed to each other thereby to form an integrated rotatable furnace, and a single means is provided for rotating said sections.

8. A furnace in accordance with claim 1 further characterized by having web means within said hood means, said web means being adapted to control the points at which said fiuid is introduced into that section into which said solids are transferred.

9. A furnace in accordance with claim 1 further characterized by having means within at least one of said sections adapted to retard the ow of said solids through said section.

10. A furnace in accordance with claim 1 wherein said furnace charging means comprise means for introducing fluid under and into said solids and means for introducing fluid above Isaid solids.

11. A furnace in accordance with claim 1 wherein said sections are steel shells lined with a refractory material.

12. A furnace in accordance with claim 11 further characterized by having means associated with the discharge end of said sections adapted to cool said steel shells.

13. A furnace in accordance with claim 1 wherein there are provided separate means for rotating each of said sections.

14. A furnace in accordance with claim 1 further characterized by having means associ-ated with said hood means for controllably introducing a solid reactant into said solids within said section.

15. A furnace in accordance with claim 1 further characterized by having means for preheating said fluid prior to its introduction intosaid hood means.

16. A grateless incinerator particularly adapted to burn refuse containing solid materials which melt during burning, comprising in combination:

(a) a plurality of rotatable, axially aligned sections maintained in telescoping relationship with each other such that the charge end of each section, except the rst, forms an overlap and surrounds the discharge end of the preceding section and defines therewith an annular passage which is parallel to the wall dening the overlapping section; the axis of said incinerator from its charge end to its discharge end forming a small acute angle with the horizon whereby each of said sections is adapted to feed said refuse by gravity to a succeeding section;

(b) separate stationary hood means surrounding and enclosing each of said overlaps and defining with at least a portion of said annular passage an air passage adapted to introduce air at least under and into said refuse as it is transferred during burning from section to section;

(c) stationary end means adapted to close said iirst section;

(d) means associated with said end means for introducing said refuse and air into said rst section;

(e) stationary discharge receiving means enclosing the discharge end of the last of said sections;

(f) means for introducing air into said hood means;

(g) means for supporting said sections for rotating;

and

(h) means for rotating said sections.

17. An incinerator in accordance with claim 16 wherein said stationary hood means has means for introducing air into said sections above said refuse at predetermined points.

18. An incinerator in accordance with claim 16 wherein said sections are alTixed to each other thereby to form an integrated rotatable incinerator, and a single means is provided for rotating said incinerator.

19. An incinerator in accordance with claim 16 including means for preheating at least a portion of said air prior to its introduction into said incinerator.

20. An incinerator in accordance with claim 16 wherein said sections are of cylindrical configuration of increasing diameter.

21. An incinerator in accordance with claim 16 wherein said sections are of frustoconical configurations.

22. An incinerator in Iaccordance with claim 15 wherein said sections are formed as refractory-lined steel shells.

23. An incinerator in accordance with claim 15 including means for introducing auxiliary fluids along with said refuse into said rst section.

References Cited UNITED STATES PATENTS 3,042,389 7/1962 Gieskieng 110-14 X 3,116,055 12/1963 Pixley et al 263-32 3,242,888 3/1966 Klovers et al. 110-l4 3,295,930 1/1967 Swanson et al. 263-32 X 3,357,382 12/1967 Matteini 110-14 3,360,250 12/1967 Malmberg 263-32 JOHN J. CAMBY, Primary Examiner.

U.S. Cl. X.R.