US2936724A - Incinerator construction - Google Patents

Description

May 17, 1960 J. w. BISHOP 2,936,724

INC INERATOR CONSTRUCT ION ATTORNEYS May 17, 1960 J. w. BlsHoP 2,936,724

V` INCINERATOR CONSTRUCTION Filed June 4, 1958 f '7 Sheets-Sheet 2 ATTORNEYS May 17, 1960 J. w. BISHOP 2,936,724

INCINERATOR CONSTRUCTION Filed June 4, 1958 7 Sheets-Sheet 3 IN VENTOR Bmwyfaw ATTORNEYS May 17, 1960 J. w. BlsHoP 2,936,724

INCINERATOR CONSTRUCTION ATTORNEYS May 17, 1960 .1.w. BISHOP 2,936,724 y INCINERATOR CONSTRUCTION Filed June 4, 1958 '7 Sheets-Sheet 6 ATTORNEYS May 17, 1960 J. w. BlsHoP INCINERATOR CONSTRUCTION "r Sheets-Sheet '7 Filed June 4, 1958 B' /55/ INVENTOR Jolm WBisIw/v www4/05M ATTORNEYS States Patent 2,936,724 INCINERATOR CONSTRUCTION Jahn W. Bishop, Alexandria, va. Application June it, 1958, Serial No. 739,915

13 Claims. (Cl. 11o-1s) This invention relates to a new and improved incinerator construction for the combustion of various types of waste products and more particularly, involves a novel arrangement of elements that peculiarly adapt this type of assembly to small portable units as well as larger structures of more commercial utility.

As a prefatory general description of my invention, the same involves substantial variants over the prior art, primarily in the concept of use of an induced, preheated air supply. Preheating in and of yitself of the combustion medium involves a two-fold function inherently achieving superior results: iirstly, preheating of such medium enables rapid combustion of otherwise relatively incombustible or diicult to burn substances such'as4 v wet leaves or garbage, etc.; secondly, the continuous preheating of the combustion air, controlling its ow in a definite path around and then through the combustion chamber, cools those elements of the construction which would rapidly deteriorate because of the relatively high temperatures resultant upon rapid combustion due to such preheated, induced air flow. In other words, this improved incinerator of my invention, by controlling -air flow in a manner to be described throughthe grates and other flame contacting parts, eliminates the necessity of expensive, oxidationeresistant materials in the fabrication of the unit, yet at the same time enables complete and efficient combustion of all the materials charged to the furnace, even including combustion of Vsuch remaining smoke or small particles as may be'thenormal rev sult of usual combustion procedures. z

That incinerator arrangements of various types are well known to the prior art is ofcourse acknowledged. However, known types of such units are more generally than not burdened with structural features that alternatively make them too expensive for the ordinary consumer, or if of the more simplied type, involve mechanical devices which, subject to direct Iand uncontrolled ame at high temperatures, soon deteriorate through corrosion and/or subiection to heat at inordinately high temperatures. The usual type of incinerator for commerical purposes and Vindeed even for homer use, if it be one that will effectively and completely burn all types of refuse, is a type involving use of an artificial combustion medium, i.e., such furnacesin order to -achieve the desired result employ auxiliary fuel or forced feed burners of the gas or fuel oil type. Extraordinarily high temperatures are obtained, but on the other hand such prior art schemes, in failing to appreciate the practical concept of air cooling simultaneously with air preheating, must necessarily also involve the use of materials' in the combustion chamber and ygrate construction highly resistant to corrosion and heat, with consequent added cost of manufacture.

It is apparent too that where an extraneous heat supply or auxiliary fuel is necessary, the expense of opere ation becomes so commensurately increasedy as to not make it practical for thehome owner or smallbusiness operator to invest in such equipment. Furthermore, the

A4,936,724 Patented May 1,7, 1960 2 employment of burners requiring auxiliary fuels gen erally requires permanent installation of some kind, in contrast to the portable adaptability of the present invention.

In addition, even in larger incinerator constructions of the forced draft type, Whether or not an external fuel source is utilized, the obtaining of high temperatures is accomplished by a proportionate decrease in the life of the component parts of such a structure, for without adequate cooling of the elements subjected to high temper? ature, and as inti-mated in the foregoing, such elementsv rapidly deteriorate, necessitating replacement for continued operation.

The device of my invention obviates these and 'the' many other diliiculties and disadvantages necessarily irl-I herent in the operation of the ordinary and known type of incinerator by inclusion of those concepts initially expressed: an arrangement or combination wherein reversed air iiow of the combustion air leads to a preheating ofV thel same, thus Iaiding combustion, while at the'sarne time this preheating step is accompanied by a continuous,

' lower temperature of the parts exposed to elevated tem-v the -grates and Ysimilar fire-contacting parts at the velocities herein contemplated, in turn keeps these elements relatively cool, thus preventing iirst damage to them.

Accordingly, it is a primary objective of this invention to provide anincinerator construction attaining complete Iand smokeless combustion for usually' diflicult to burn and smoke-producing refuse without the use of an auxiliary fuel, the same being so simply designed so as to be portable in nature when correspondingly reduced in size and hence, ideally suited for use in the home, small business, institution or apartment requirement-s. e f

It is an additional objective of the invention to provide a unit of the described type wherein combustion air preheated by travel through a series of helical passageways in proximity to, but sealed from, the combustion chamber Abefore admission tothe combustion zone, resulting in not only complete, rapid and eicient combustion of refuse, but in smoke elimination as Well; in line with this same concept, the unit is so constructed that this same, preheated combustion air initially flows through certain of the burner parts of the unit such as the supporting grates so Eas to constantly'maintain the same at a predetermined, lower temperatureor temperatures substantially lower than'that attained by combustion of the materials charged to the unit.` AtV they same time, the inner walls of the furnace are cooled' and thus protected. Also, in versions of the invention where.Y in such passageways form an outer double wall of the combustion chamber, the exterior of the unit remains relatively cool, despite the high order of temperature attained within the incinerator.

Another object of the invention is the provisionof a structurevwherein ow of the combustion' medium induced by an external forced air supply'which isdirected through the preheating step as indicated, such achieving rapid combustion without overheating or deterioration? of those elements more or less in direct contact with thef high ltemperature ame in the combustion chamber.

An -additional object of the invention involves the provision of a unit of this type wherein the principles enumerated in the foregoing may be incorporated in a' single, air cooled stack or column arrangement, portable4 empty oil container, such portable unit operating in the same manner as indicated above-induced ilow of preheated air to achievecomplete combustion, with such air serving the adding function of cooling the essential e1ementsof the furnace in such -a manner as to preventun# due oxidation `and/or deterioration of the same. In this version, a type of air jet'is employed to induce downbznrning of the materialsV charged to the container,` the unburned combustion products thereof being drawn Vinto the stack for further complete andl smokeless burning thereof.

Another objective of the apparatus described herein is to provide a furnace unit wherein a' rotating grate is positionedvdir'ectly above a relatively air-tight plenum chamber, the grate being constructed so that it can be opened for ash disposal and closed during periods of use by an externally controlled adjustment means which is so fashioned to maintain the plenum air-tight. Actually the plenum in certain versions of the invention serves also the purpose of an ash pit, the grate when opened permitting discharge of the ash for ready removal from this chamber.

. Additional and further objectives and advantages of my invention will become apparent from consideration of the following more detailed description thereof, and having reference to the enumerated drawings wherein:

Figure 1 is a vertical section View of one embodiment of the invention illustrating one manner of preheating the combustion medium, which mediiun, ultimately charged to the combustion chamber, cools the furnace walls and grate structure during its passage therethrough.

Figure 2 is a section view taken on the line 2 2 of Figure l.

Figure 3 is a bottom plan view of the embodiment of the invention as shown in Figure 1.

Figure 4 is a section view taken on the line 4 4 of Figure 1.

Figure 5 is a section view of another embodiment of the invention, comparatively small and portable in nature and adapted for use with various types of ordinary, open toprefuse containers.

Figure 6 is a section View taken on the line 6 6 of Figure 5.

Figure 7 is a section view taken on the line 7 7 of Figure 5.

Figure 8 is a top plan view of a further and preferred embodiment of the invention.

Figure 9 is a section View taken on the line 9 9 of Figure 8.

Figure 10 is a section view taken on the line 1(1 10 of Figure 8.

Figure 11 is a section view taken on the line 11 11 of Figure 9, and

Figure 12 is a partiahelevation view of embodiment of the invention shown in Figure 11, illustrating the helical path of ilow of combustion medium as it is emitted.

from'the blower unit of this construction.

Referring more particularly to these various gures, Figure 1 represents one embodiment of the invention wherein avacuum cleaner may be used as the blower means, andthe container itself is double walled, the air from the manifold being charged into and through the helical passageways between the walls before entering the plenum.

The combustion chamber or burning zone is generallyV indicated at V1. As stated, the receptacle, generally indicated atl, is of double-walled construction, having an inner wall 2 and outer cylindrical wall 3. The inner wall 2 is a helically corrugated conduit, consisting of a series of alternate helical ridges and grooves. Actually the same resembles an exaggerated screw threaded formation of even pitch or gradient. Thus the inner wall 2 is comprised of these alternate indentations 2a and adjacent high points 2b throughout its length. The result is to form a `series of intermediate channels 9 in between the outer wall 3 and such grooved inner wall 2, all'of these channels obviously following ahelical or spiral path 7 5 from top to bottom of the unit, forcing the'air admitted to the vchannels 9 to likewise follow a spiral path around the primary combustion zone, :generally indicated at 11, from the top point of admission to the bottom of the unit, to ultimately be discharged into the plenum. Although not essential, the high points or ridges of the inner corrugated wall 2 may be welded at spaced intervals to the outer wall 3 or at such points as indicated at 4. During its spiral course downward, the combustion air becomes substantiallypreheated for the inner wall is ,directly adjacent the combustion zone. On the other/hand, the in coming air substantially cools the side walls 2 and 3, and particularly` the corrugated wall 2, preventing its overheating and consequent deterioration.

The combustion chamber "f1 rests upon a lower circu lar plenum chamber, generally indicated at 7, and defined by a continuous circular side wall 5. By a suitable weld 6 Vor other ordinary media, the container 1 is affixed to the stationary grate surmounting the plenum. The latter is provided with a suitable, circularfbase element 8 with a crimped edge 10 adapted to receive the side wall 5 in air-tight relationship as clearly shown in Figure 1.

A suitable air collector ring or peripheral manifold, generally indicated at 13, encircles the upper opening of the vcontainer 1. Such may be made unitary with the outer wall 3 with which it is interconnected, but in any event, it consists of an upper annular top 15, a corresponding annular bottom member 17, and an outer and vertical rside wall 20. The manifold is so constructed as to leave an opening 16 of a size commensurate vwith thel diameterof the inner helically corrugated wall 2 to which it is welded by a suitable weld 18. This air manifold, used for the purpose of evenly supplying air for combustion purposes to the helicai passageways 9 in between the inner and outer walls of the container, is furnished with an air inlet or diffuser pipe 25, preferably threaded as at 26, or otherwise having a suitable interlock for interconnection with the discharge pipe of a suitable blower or vacuum cleaner discharge pipe. The inlet pipe 25 tits into a corresponding aperture in the side wall 20 of the manifold and is welded thereto as at 28. Where the inlet 25 projects interiorly of the manifold, side dischargeY openings 30 as wellas an end rdischarge opening 31 are provided.

' VAt the upper portion of the interior, corrugated wall 2 a series of apertures 37 are provided, all of which are formed in the :alternate grooves 2a of the inner wall. As` seen in Figure 1, these extend down only a relatively short distance from the upper opening 16 and are adapted toadmit combustion air from the manifold to the topm'ost portion of the combustion zone 11 in order to completely burn'all of the resultant sm'olteor small particles consequent upon'primary burning in the lower portion ofthe combustionzone Asseen Vin Figure 2 air under pressure from the` manifold readilyV progresses into the spaces` 9 through the openings 9a which represent the ends of the helical passageways 9 at the upper edge of the container.

The combustion chamber 11 is'ftted with two circular grates at its lower end. These support the materials to be burned and also permit a controlled discharge of the resultant ash. There two grates are super-imposed one above the other, the lower grateY 4t) being stationary with respect 'to the unit and aixed in position by a peripheral weld 41 which is united with the inner, bottom edge of the corrugated helical wall '2. This lower stationary grate 470, obviously circular in configuration to adapt itself to a complementary fit with such elements as the outer wall 3 and the plenum chamber wall 5, is provided with a series of equally sized segments or sectors as will be appreciated from viewing Figure 4. Such segments consist of alternate'solid sectors 42 with intermediate open segments V48 las seen in this ii'gure. There heini,7 twelve alternate open and perforated segments, all of such segments s ubtendan arc of 30.

't To permit air flow into the combustion chamber duringburning, each of the solid segments 42 is provided with anadequate number of suitable apertures or openings 45.`

Although the number of segments in each grate may be varied to suit various operative conditions,lhave here, in this embodiment` of the invention, described six perfforated segments in each grate, spaced from each other by six intermediate, open sectors.

The upper grate `55 is of similar shape but rotatably mounted and superimposed upon the lower grate so as to be in slidable contact therewith. This upper grate similarly consists of an alternate series of pie-shaped, perforated segments or sectors 60 and alternate open sectors 61, as appreciated from viewing Figures 1 and 2; Each of the solid segments of the upper grate extending from the concentric hub 58 of the same is provided with a series of holes or apertures 62, similar to the openings 45 made with respect to the lower grate 40.

The central hub portion 43 of the lower grate matches the hub 58 of the upper rotatable grate.

Since the alternate aperturedv and open segments 'of both the upper and lower grates are of corresponding dimension, when the upper grate is so rotated as to place the solid segments thereof over the open sectors of the lower grate, the entire grate construction will be closed (except for the multiple series of air inlet openings), as shown in Figure 2. Alternately, when the upper grate solid segments 60 are rotated 30V", they will be positioned in alignment with the solid segments 42 of the lower grate. The open sectors of each, 48 and 61 respectively, will also then be in alignment leaving this proportion (or one-half of the total surface area) open for the discharge and removal of ashes from the combustion chamber.

There must of course be an egress for the descending column of air spirally traveling downward through the helical channels 9. To this end, the bottom grate 40 is provided with a series of air slots 65, here shown to be eight in number, but in any event, positioned in between the walls 1 and 2 of the combustion chamber to open into the several passageways 9. Thus, the airflow through the apparatus thus far described is initially into the manifold 13 through the several interior channels 9 and thence out of the air slots 65 into the plenum chamber 7.

The lower stationary grate -40 and the bottom 8 of the unit are spaced apart by an additional support 70 which serves-the additional function of accommodating the pivot for, turning the upper rotatable grate. This tubular member 70 is welded at both ends as at 71 and 72 to the lower grate and the bottom plate 8, respectively. Mounted within such tubular support 70 is a pivot 75 takingthe form of an elongated tubular or solid rod, which extends at its bottom end a short distance beyond the bottom 8 and which at its upper end terminates in a boss 76, the pivot 7 0 extending through appropriate apertures in the hubs 43 and 58 in the lower and upper grates, respectively. The boss 76 is welded as at 78 Vto the upper grate hub 58 so that the pivot 75 and upper grate are, in effect, an integral unit. Hence, withrotat-ion of the pivot pin 75, the upper grate is equivalently rotated. Y

A manual means for rotation of the grate at least 30 to superimpose the solid portions of the upper grate above the openings of the lower, or to position the solid portions of each in alignment, thus opening the grate structure for ash discharge, is found in the lever 80. This is provided with a reduced end portion 81, adapted to lit within a corresponding slot suitably bored in the lower end of the pivot pin 75 as clearly shown in Figure l. A bolt 82 maintains the lever |80 in this secure position. The latter can be provided with a convenient handle 88 y.for adjustment purposes, the lever itself 'extending out- :side of the incinerator unit an appreciable :distance throughslots 85, cut through-both theplenumchamber side wall 5 and the ange portion 10 of the bottom wall 8. For purposes of strengthening the bottom 8 near the pivot element 78, I have found it preferable to position two angle irons 87 and 88, affixed by welding tothe underside of the bottom 8, positioned parallel to each other and directed toward the referred to slots 85. Y

The plenum chamber 7 constitutes also the ash pit for the combustion chamber, and removal of ashes is made possible by tting a usual type of door 90 over an appropriate opening 91 cut in the side wall 5 of the cham ber. This door may be hinged at one side as at 92 and provided with adequate locking means such as the yhasp 93 which accommodates the locking lever 94.v Since the chamber 7 should be relatively air-tight, any form of lireresistant gasket means, known to the art, may be posi'- tioned upon the door for sealing the same after closure.

In the preferred embodiments of this invention the combustion supporting mediumisV supplied under pressure. lIt is important that the other structure be such as to be air-tight throughout. From the description above of the manifold and its interconnection to the inner and outer walls of the combustion chamber, it will be appre ciated that all of these elements are individually air.- tightly connected. This is true also of the plenum chamber, the unique arrangement permitting rotation or adjustment of the upper grate and being such as to maintain an air-tight seal in this chamber. That is, and in reference to the structure just described, it is clear that the lever and its accompanying pivot 75 are completely closed off from the chamber 7 so that air under pressure cannot escape.

From the foregoing, the operation of this embodiment ofthe invention should be apparent. Air admitted to the manifold under pressure is caused to travel a helical and spiral'path downwardly, to be emitted into the plenum chamber. During its course, certain of such combustion supporting medium, as overire air, is discharged through 'the openings 3-7 at the top of the unit to substantially aid the completion of combustion at this point, particularly by burning the smoke emanating from the primary combustion zone. The remainder, entering the plenum chamber, is caused to pass upwardly into the combustion chamber through the alternate series of openings 45 and 62, in the two grates, when the apertured sections are alternately positioned so that all of the open sectors in the bottom grate are closed. The progress of air through the passageways 9, all of which are adjacent to the combustion chamber and heated by it, naturally preheat the air prior to its entry to the plenum, thus raising its temperature in a manner to facilitate and promote combustionA within the unit. At the same time, even though the grates are subjective to direct tiring and the hottest portion of the charge within the unit, these grates and their accompanying structural elements are not raised to a deteriorating high temperature because the preheated air is constantly in contact with such elements and, having beenk raised only to the temperature of 860 F. or less,is relatively cool, and thereforeconstantly cools these iire contacting elements. |lfhe same eect is true with respect to the combustion chamber itself, for the descending, cooler air, spiralling about the combustion chamber in the passageways 9, will maintain the inner wall` of the furnace at a temperature substantially lower than the relatively high 'temperatures of combustion withinthe unit. Also, the outer skin 3 is cooled by the travelof forced air through the several helices, the result being that the. exteriorV of the incinerator is suiiiciently cooled to be perfectly safe to the user from an operative viewpoint.

Perhaps the most compact and portable example of the invention is found in the embodiment thereof illustrated in Figures 5, 6 and 7. Here the device is 'one to be fabricated and sold at a self contained, air-tight and compact unit, for use in almost any Ytype of suitable containerthat would'be available toany householder.Y In

7 the example here represented, the device .is shown .for use in conjunction with a container such as an open oil drum, generallyindicated at ldd, and of course provided with the usual circular side Wall 161 and base 102.

The assembly of the invention in this embodiment similarly employs a spiral or helical tubular member `as the core element. In the same fashion as in the example described above, an exterior tube 11d sur- .roundslthis corrugated core 105 .in contact with the outermost ridges thereof .so that the spiral convolutions form helical air passageways or spaces 112 in between the inner wall 105 and the outer wall 110.

The helical, .corrugated stack 105, with its outer .wall 110, .is mounted upon a stack plate 115 consisting of a circular member with a downturned side wall 120. The upper face vof such plate is welded as at 116 to the outer wall 110 of the stack, andthe side walls 120 of the plate arrangement are in turn welded as at 122 to another circular or rectangular base 120 which is, in effect, an integral part of this portable unit, the base 121 being of suicient dimension to enable vertical placement of the stack within any type of container in self supporting fashion, and as shown in Figure 5. The base 115 with its downturned side wall 120, when aflixed to the base 121 in the manner shown in Figure 5, form, in effect,

a smaller plenum chamber, generally indicated at 123.

Air flow from a suitable pressure source is provided in the same manner. A manifold, generally indicated at 125, distributes air throughout the upper edge of the stack; the air then spirally descends into the lower portion of the unit. The air collector ring or manifold is of a `construction `similar to that already described with reference to Figure 1. It consists of an annular top 126, an annular bottom wall 127, and a circular side wall 128, all of which may -be integrally fabricated with the outer wall 110. In any event, the top wall 126 has a concentric opening 130, the rim of which is welded as by weld 131 to the upper edge of the helical corrugated stack 105, thus making the manifold air-tightly connected to the stack and the helical passageways 112 in between the inner corrugated stack and the outer wall 110. Also, in similar fashion, the air collector ring is fitted with an inlet pipe 132, threaded as indicated, and provided at its end portion with side openings 133 and end outlet 135, all discharging into the interior of the manifold.

After emission lfrom the manifold through the upper ends of the helical passageways (designated as 112:1 in Figure `6), the air vprogresses downwardly to the bottom of the stack and through a series of air slots 135 formed nearv the periphery of the base 115 and so `located as to .bein between a groove of the helical stack 105 and the youter wall 110, i.e., the slots 135 open directly Yinto the respectivepassageways 112. This feature of construction Vcan be vreadily understood by reference to Figure 7. The air ow is thus induced into the plenum, generally indicated at 123, and it is then directed to a ydischarge pipe 139 which terminates in a venturi-type of spout or nozzle 140. The Vpipe 139 is welded at its lower end, as at 143, to the stack plate 115, a suitable aperture to accommodate the pipe being formed therein. VTheventuri or spout 140 is positioned in axial alignment with the stack and concentrically with respect thereto. In addition to the ow of primary air through the helical passageways and plenum, an induced air How is accom- .plished by a series of holes or openings which are bored through both the helical corrugated stack and the .outer wall 110 at the point where such corrugations contact the Wall 110. In other words, there is a direct inlet from the 4interior of the container 1610 to the interior of the stack.V It will be noted thatthe induced air inlets Y 4145 extend from just above the stack plate 115 to .a point even with, or slightly below, the outlet of the nozzle 140. This Yrelative position of nozzle and air .inletsetectuate aninduced'airow into the stack. `Disi A,panded metal.

charge .of .secondary air from theVnozzle 140 vinto .the stack creates a partial vacuum which draws the combustion products out of the refuse through the openings 145 into admixture with such secondary air to bum the smoke `producing volatiles. The operation of this unit is similar to that of the embodiment heretofore described, except that the burning of the charge to the .incinerator by primary air may be termed downburning for the action of the venturi 140, with its secondary air dow through the passageways and the plenum, is to induce air ow downwardly through the charge of material, through the openings 140, and into and upwardly throughout the length ofthe stack. Combustion products in this type of unit, if any remain, therefore are ultimately discharged through the upper opening 130 ofthe stack.

In the operation of such a unit, complete combustion of the charge is obtained in a smokeless fashion since the down ow burning prohibits discharge of smoke from the upper surface of the charge and out of the container, while at thesame time secondary air, preheated as before, induces ow from the refuse container through the stack. Thus, the V products of combustion in the container 100, before emission to the atmosphere, are further burned in the stack. The result is a virtually smokeless operation, the primary and induced air ow creating temperatures ,of a high order in the zone of primary combustion-the 'burning zone in the container 100.

In this embodiment the plenum is similarly of an airtight construction as will 'be appreciated from the fore- ;going, so that the air jet '140 and the related elements of the structure are all effective `to utilize the full pressure of air admitted to the manifold. Also, the downwardly spiralling air performs the same two-fold func- `tion:` it becomes preheated during its progress through the helical passageways, and it protects the stack by cooling the same.

A further improved version of the invention is illustrated in Figures 8 to l1, inclusive. In this modification, an attached blower unit is located at the base of` the furnace, and although the same basic concept is contemplated (preheating of the combustion air with conjoint cooling of the combustion chamber walls, the grate, etc.`), a different arrangement is provided for complete combustion .of the smoke and other combustion products which originate vin the primary burning 'chamber.

Referring particularly to lFigures 8 and 9, it is seen that the same basic form of combustion chamber is utilized. Such consists of the helically corrugated inner wall '150 to which is attached, immediately adjacent thereto, an air casing lor outer wall 152. The kresult is :to have the helical passageways1154 running spirally labout the furnace and from top 'to bottom of the unit. The inner, corrugated wall may be welded, as at 156, to the surmounting manifold; the outer casing 152 is attached to the bottom or base 155 by a suitable weld 157. Such a unit, like the other variants herein described, is of moderate size, indicated by the two carrying handles V158 which permit lifting and movement of the incinerator by a single person.

The referred to manifold is provided with the usual top Wall 160, circular lbottom 161, and peripheral side wall 162, all of which maybe fabricated integrally, kas before, with the outer air casing 152. The top 160 of the manifold contains a substantial opening for the insertion of materials to be burned, and a suitable cover '166 isprovided, such being hinged as at 168 land provided with a handle 170, so that during operation, the incinerator unit can be kept closed.

'The `grate 175.is here shown as being made of eX- Circular in configuration to match kthe vinternal 4diameter `of the .corrugated ,inner wall, kthis lgrate yis positioned .upon V,an .annular v'flange or. ring kv17,31

which is suitably vpositioned across the furnace and underneath the primary combustion zone thereofas indicated at Figure 9. The grate merely rests upon this annular ring and thus can be pivoted upwardly in order to permit dumping of the ashes, the operator merely lifting the grate control rod 177 for this purpose. Such assenze' control rod is affixed by any suitable method, as a hook and eye arrangement 178, to the annular ange 179 which carries the expanded metal grate, as also depicted in Figure 9. The upper end of the rod is bent right angularly to form a handle 181.

' At a point below the grate, both the helically corrugated inner wall and the outer air casing are cut to form a suitable ash removal opening 179, and such is Vcovered by a door 180hinged at one end as at 182 and provided with a suitable interlock 183 to maintain it closed and in relatively air-tight lassociation around the adjacent sides of the, referred to ash pit opening. An asbestos gasket may be fitted to the door opening to achieve the latter function. s l Y The ash'pit-plenum chamber, here generally designated at 184, is of course located immediately underneath the grate 175. It receives a supply of primary air from the blower unit, to be referred to, through a series of air inlet slots 185 which are formed-in the upper corrugated wall 150. These' slots lead directlyv from the severalV helical passageways 154` as willbe understood by reference to Figure 9. The angular position of these slots coincides with the angularity of the helical grooves formed by the corrugated inner wall 150. These air slots are located relatively close to the base 155- of the unit and receive approximately half of the air forced through the downcomers or half of the helical passageways'154.

In this example of the invention, two stacks are provided, vone within the other, to obtain, as will be seen, complete combustion of such unburned smoke or particles as may be discharged from the helically corrugated furnace. Y

The inner stack 190 ofthe two-stackarrangement is positioned adjacent one side of the furnace or to one side of the door 166 referred to above. lThe lower, open end of this stack is canted or mitered las indicated in Figure 9, and the lower opening covered with a suitable screen 193 of a mesh size designed to prevent any substantial amount of ashes orunburned refuse from enteringthis stack. The mitering of the end of the stack permits raising of the grate by means of the control rod 177, to a level allowing discharge of the ashes to the ash pit.

At its upper end and immediately underneath the top 160 of the manifold, the inner stack 190 is provided with a seriesV of relatively small holes or inlet openings 195 permitting some combustion products of the primary burning procedure to pass upward therethrough, thus fur- 10... Y inner and vouter stack and upwardly along that annular space to mix with the combustion gases at the top of the inner stack. During the travel of such induced air through the outer stack air casing and along the annular space referred to, this induced air becomes preheated. Such preheating further ensures combustion of the unburned volatiles which are passed through the apertures 195 .from the primary combustion zone and which would otherwise be emitted as white smoke out of the outer stack'200. The described arrangement thus attains a completely smokeless operation.

As stated in the foregoing, the blower for forced feed of combustionvair into the unit is located at the bottom of the incinerator (see Figure l2). This blower B is appropriately fitted into the usual type of blower manifold 230, the latter being mounted within a suitable entry formed in the outer wall only (air casing 152). Referring to Figure 1l, it is seen that the blower is so mounted that half of the air supply is directed upwardly through the corrugated helices or passageways 154 (the risers) whereas the other half is forced downwardly through the same helix formation and passageways 154 (the downcomers) to enter the air inlet slots 185 formed in the inner wall, as above described. To make this clear, reference should be had to Figures 9 and l2.v In Figure 9, the descending air How is shown as entering such air slots 185, whereas in Figure l2, the ascending air ow is indicated as swirling'upwardly to ultimately enter the surmounting air manifold.

ther promoting combustionY and additionally Vremoving moisture from the unburned balance of the materials in theA primary combustion zone..

The inner stack preferably extends upwardly above the top of the furnace a distance approximating one-half of the height of the unit. Also, the inner stack 190 is enclosed within the referred to outer stack 200 which is concentrically spaced an appreciable distance from the inner stack by suitable spacers201 located in between thev said` inner and outer stacks. Such outer stack 200 is mounted upon an additional, small plenum chamber Aor outer stack air casing 205, the latter, through opening 206, feeding directly into the stack 200, which in turn is welded as at 208 to the air casing 205.

The air casing 205 (viewing Figure 8) is seen to exl tend somewhat less than one-third ofthe distance across the top of the unit. It is closed to the atmosphere throughout except upon opposed sides thereof where the side wall of the chamber is provided with approximate slots. or openings 210 Vand 212; these air inlets permit the induc\ tion of air from the atmosphere into the outer stack cas! ing 205 through the peripheral space 206 between the lTo summarize the operation of this embodiment of the invention, such may be described as follows: it is to be appreciated that there are a total of eight inlet openings into the plenum 184. The blower B feeds directly into only four of these inlets as clearly indicated in Figure 12. Hence, the incoming supply of air from the blower is directed upwardly through these four (which thus may be termed the risers) and into the air collector ring or manifold. The forced air supply in the manifold then-feeds directly into the remaining four of the helical 'passageways-154. These may be regarded as the downcomers. 'I'he air from such downcomers, or the remaining four of the helical passageways 154, discharges directly into the plenum inlets 185. Hence, there is concurrent flow of air throughoutthe double side wall forming the combustion chamber with the result that such air is most eiciently preheated to a relatively high temperature. Manifestly, this facilitates combustion in the primary combustion zone to such a degree that relatively high burning temperatures are obtained. Furthermore, this thorough contacting of the primary air throughout such side walls of the combustion zone maintains the same in relatively cool' condition, i.e., inV contrast to the elevated temperatures of the burning process itself, which will run substantially higher than the temperature of the preheated air. Also, as in the other examples, this preheated air has a substantial cooling effect upon other related elements, such as the grate, stack screen 193, etc., thus protecting the same from damage due to the elevated combustion temperatures which are obtained.

, The majority of combustion gases pass through the hottest part of the fire (within the furnace proper) into the zfopened, rnitered rend of the inner stack 190; a smaller portion continues upward to be discharged into the holes in this same stack to promote the drying of the wet refuse and at the same time to provide some upward preheating of the incoming combustion air as well as the' cooling eiect such air has upon the grates and relating apparatus used to support the materials being burned. Preheating of the air forces combustion to take place where ordinarily it would not, particularly with respect to damp or wet material. The induced air ow whether induced by an external blower means or by the natural venturi action of the arrangement, e.g., of Figure 3, further ensures rapid and complete combustion of the materials charged to the unit.

In actual operation it has been found that the heat of combustion in the primary combustion chamber is of such a degree to not only burn, for example, wet garbage, but to even weld metal cans together, melt down bottles and similar materials ordinarily regarded as completely noncombustible. Such indicates the degree of high temperature attained within the furnace, yet because of the cooling eect of the preheated air, controlled to cool down those parts subjected to such high temperature, various elements of the incinerator are fully protected and will not deteriorate over long periods of usage. Also, in actual use, a device made in accordance with this invention has burned from fourteen to twenty gallon cans of garbage and an estimated tive or six cubic yards of wet leaves before requiring ash removal, indicating the thoroughness of the burning procedure. It was found that the volatiles which are distilled from the refuse from the main combustion chamber by the preheated air are burned in the upper sections of the various types of incinerators, such resulting in a smokeless gas llame. During yoperation of one ofthese units, it was observed that white smoke (produced as a result of the latent heat removal in the boiling ofi of the water in the charged materials) would soon ignite as the operation continued with au immediate resumption of a smokeless burning operation. During function of one of these units, there was no emission of yash, further demonstrating the completeness of combustion obtained by this improved unit.

It is obvious'that this invention may be varied in many ways and other expedients employed to accomplish the,

purposes thereof; however, it is to be understood that my invention is only limited by the scope of the appended claims.

I claim:

1. In an incinerator unit, anV open cylindrical container for refuse to be burned,'said container having outer and inner upright side walls enclosing a combustion chamber,v said inner wall having corrugated helical grooves throughout forming helical passageways substantially from top to bottom thereof, said passageways being in indirect, heat conductive communication with the interior of said chamber, an air collector ring adjacent said top and in communication with said passageways, an air-tight plenum chamber adjacent said bottom and in communication with said passageways, a rotatable grate above said plenum chamber, means to rotate said grate to open and closed positions from a point exterior to said container, and means to admit air under pressure to said air collector ring, whereby said air travels downwardly and helically into said plenum thereby becoming preheated in said passageways before ,discharge into said combustion chamber.

2.` In an incinerator unit, an open cylindrical container for refuse to be burned, said container having outer and inner upright -side walls enclosing a combustion chamber, said inner wall having corrugated helical grooves throughout forming helical passageways between said outer and inner walls extending substantially from top to bottom thereof, said passageways being in indirect, heat conductive communication with the interior of said chamber, an air collector ring adjacent said top and in communication with said passageways, overre air inlet means at the top of said container communicating with said passageways, an air-tight plenum chamber adjacent said bottom and in communication with said passageways, a stationary and rotatable grate `above said plenum, each of said grates being of circular shapeand divided into open `and closed sectors, means exterior of said container to moveA said rotatable grate to open and closed positions, and means- `,to admit air under pressure to said airrcollector ringV whereby said air Vtravels downwardly and helically into sa'id plenum thereby' becoming preheated in said passageways before discharge into said combustion chamber.

3. In an incinerator, an elongated, open stack having inner and outer walls and forming a combustion chamber, said inner wall being helically corrugated to provide a series of spiralled passageways between the inner and outer wall, said inner wall being in direct, heat conductive association with the interior of said combustion chamber, an air collector ring at the top of said stack in communication with said passageways, a substantially air-tight` plenum chamber in communication with said passageways at the bottom of said stack, a nozzle in said stack and coaxial therewith, said nozzle communicating with said plenum chamber, said walls having openings to the eX- terior adjacent said nozzle, and means to force air into said air collector ring, whereby air llow is induced into said stack through said openings.

4. In an incinerator, an elongated, open stack adapted to be positioned in anopen refuse container, said stack having an inner and an outer Wall and forming a combustion chamber, said inner wall being helically corrugated to' provide a series of spiralled passageways between said inner and outer walls, said inner wall being in direct, heat conductive association with the interior of said combustion chamber, an air collector ring at the top of said stack in communication with said passageways, a substantially air-tight plenum chamber in communication with said passageways at the bottom of said stack, a venturi tube comprising a nozzle in said stack and coaxial therewith, said nozzle extendingy from said plenum chamber, said stack having openings to the exterior positioned opposite said venturi-tube, and means to force air into said air collector ring, whereby air flow is induced from said c011-` tainer into said stack through said openings.

5. In an incinerator, an elongated, open stack adapted to be positioned in an open refuse container, said stack having an inner and outer wall, said walls forming a com- Ibustion chamber, said stack being mounted upon a selfsupporting base plate, said inner wall being helically corrugated to provide a series of spiralled passageways between said walls, said inner wall being in direct, heat conductive communication with the combustion processes in said chamber, an air collector ring at the top of said stack in communication with said passageways, a substantially air-tight plenum chamber in communicationwith said passageways at the bottom of said stack, a venturi means comprising a nozzle in said stack and coaxial therewith, said nozzle being mounted on said plenum chamber and in communication therewith, said stack having openings to the exterior opposite said nozzle, and means to force air into said air collector ring, whereby air flow is induced into said stack from said container through said openings, and air from said air collector ring' is preheated in said passageways.

6. In an incinerator unit, a cylindrical combustion chamber having contacting inner and outer walls, said inner wall being in direct, heat conductive communication with combustion processes in said chamber, Vsaid inner wall having helical corrugations therein forming helical passageways between said inner and outer walls extending from top to bottom thereof and forming helical preheating passageways, a substantially air-tight plenum at the bottom of said chamber having an air inlet in communication with one of said passageways, a manifold at the top of said chamber, a blower means in interconnection with another of said passageways, a grate above said plenum and a stack means in communication with said chamber and leading to the atmosphere, whereby vair admitted to said another passageway is conducted to said' I manifold and then to the said one of said passgeways,

said air being discharged to said plenum after being preheated in Vsaid passageways.

7. In an incinerator unit, a cylindrical combustion chamber having contacting inner and outer walls, said inner wall being in direct, heat conductive communication with combustion processes in said chamber, said inner wall having helical corrugations therein forming helical passageways between said inner and outer Walls extending from top to bottom thereof and forming helical preheating passageways, a plenum` at the btoom of said chamber having an air inlet in communication with one of said passageways, a manifold at the top of said cham- 8. In an incinerator unit, a cylindrical combustionv chamber having inner and outer contacting walls, said inner wall having helical corrugations therein to form helical passageways between said walls, said inner wall forming a plurality of helical downcomers and a plurality of helical risers extending from top to bottom of said wall, a plenum at the bottom of said chamber having air inlets in vcommunication with said downcomers, a maniyfold at the top of said chamber, a blower means in interconnection with said risers, a grate above said plenum and a stack means in communication with said chamber and leading to the atmosphere, whereby air admitted to said risers is conducted to said manifold and then to said downcomers, said air being discharged to said plenum after being preheatedrin said passageways.

9. In an incinerator unit, a cylindrical combustion chamber having inner and outer contacting walls, said inner wall having helical corrugations therein to form helical passageways between said walls, said inner wall forming a plurality of helical downcomers and risers extending from top to bottom of said wall, a plenum at the bottom of said chamber having air inlets in communication with said downcomers, a manifold at the top of said chamber, a blower means in interconnection with said risers, a grate above said plenum, an inner and outer stack means, said inner stack means opening into said combustion chamber adjacent said grate and having overiire inlets communieating with said chamber at the top thereof, said outer stack being provided with an air casing to receive and preheat air for `admission to the annular space between the said inner and outer stack means for the burning of discharged smoke particles from the combustion chamber, whereby `air admitted to said risers is conducted to said manifold and then to said downcomers, said air` being discharged to said plenum after being preheated in said passageways. t

10. In an incinerator device for burning waste materials, a cylindrical combustion chamber, said chamber including a vertically disposed waste gas stack means within the cross-sectional area thereof,'said chamber having an upright outer wall and an inner wall provided with helical corrugations, said corrugations ycomprising a series of spiral indentations and corresponding ridges, said ridges extending laterally into said combustion chamber, said Walls being in contacting relationship with each other, said corrugations forming helical passageways around said chamber, said passageways being in direct, heat conductive communication with combustion materials in said ber, a blower means in interconnection with another of chamber, an air-tight plenum'under said chamber and in communication therewith, said passageways at the lower ends thereof being in communication with said plenum, an air collector ring in communication with said passageways at one end thereof, means to force combustion air into said air collector ring and downwardly into said' plenum, whereby, during operation of said device, the heat of combustion is directly imparted to said inner wall and said passageways to preheat said air prior to intermingling thereof with said materials to support the combustion thereof.

1l. In `an incinerator unit for burning waste materials, a combustion chamber having an exterior, upright side wall, an inner wall directly adjacent said chamber and in indirect heat conductive relationship therewith, said inner wall being in contact with said upright side wall, said inner wall comprising a corrugated element provided with a series of spiral indentations and corresponding ridges, said ridges extending laterally into said combustion chamber, said spiral indentations between said walls comprising a series of helical air-preheatng passageways, an airtight plenum under said chamber, and in communication therewith, an air collector ring in communication with each of said helical passageways at the respective upper ends thereof, means to force airinto said air collector ring and vdownwardly through said passageways to preheat *he air, and means to discharge said air` from said passageways at the respective lower ends thereof into said plenum prior to intermingling with said materials undergoing combustion in said combustion chamber. q

12. In an incinerator unit for burning waste materials, a combustion chamber, an air pre-heating double wall directly adjacent said chamber, said double wall comprising an inner and outer wall of heat conductive material,

`said inner wall having helical corrugations extending ways at one end thereof, and means to force air into said air collector ring and through said passageways to preheat the air, and thence into said plenum prior to intermingling with said materials undergoing combustion in said combustion chamber.

13. In an incinerator unit, a cylindrical container for refuse to be burned, said container having an upright side wall enclosing a combustion chamber, means to preheat combustion supporting gases before admission to said combustion chamber, said means including an inner Wall contacting said side wall, said inner wall having helical corrugations extending laterally into said chamber and with said upright wall forming helical passageways extending substantially from the top to the bottom of said container, said inner wall being directly exposed to said combustion chamber, an air collector ring adjacent said top and in communication with said passageways, an airtight plenum chamber adjacent said bottom and in communication with said passageways, a rotatable grate above said plenum, and means to admit air under pressure to said air collector ring, whereby said air travels downwardly and helically through said passageways into said plenum thereby becoming preheated before discharge into said combustion chamber.

References Cited in the tile of this patent UNITED STATES PATENTS 119,718 -Rand Oct. 10, 1871 1,794,056 Borgeson Feb. 24, 1931 1,886,760 Tierney Nov. 8, 1932 2,201,627 La Mont May 21, 1940

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