US2847950A - Incinerator - Google Patents

Description

L TA1 2 Sheets-Sheet l M. A. NAULIN INCINERATOR Aug. 19, 1958 Filed July 25, 1955 M. A. NAULIN Aug. 19, 1958 INCINERATOR 2 sheets-SH Filed July 25, 1955 United States Patent Olhce 2,847,950 Patented Aug. 19, 1958 INCINERATOR Mick A. Naulin, Milwaukee, Wis. Application' .lulyv 25', 1955, Serial No. 524,223 6` Claims. (Cl. 11G-8) This inventionV relates: to incineratorsv and' refers more particularlyY tot improvements in incinerators of the type shown in the copending application or Abner M. Naulin (now byV change of name Mick A. Naulin), Serial: No. 394,608-, filed November 27, 1953, now PatentNo'; 2,805,- 633, of which this isa continuation in part. t

That: application discloses an incinerator having front, rear, -top' and side walls of modular c'onstructionrrand having a partition wall; extending from one; side wall: to the; other intermediate the front and rear Walls, to separate the interior of the in'cinerator intoa combustion compartment in front oi? the. partition' wallland an expansion chamber behind the partition wall. The top edge off the partitionwall is spaced' below the topwall to permit combustion gas fromy thev combustion chamber to how thereover into the: expansion chamber, whence combustion; gas leavesy the incinerator through. auf outlet cenL teredin: the rear of the incinerator, near the; top` thereof.

Behind the partition Wallis a drop wall which extends from one side wall tothel other andC which` dependsfrom the top wall, with its` lower edge spaced belowlthe upper edgeof the partition wall to cooperate therewith in de'= ning al narrow throat through: which the combustion: gas hows before entering! the expansion chamber.. Asi the gases.` how through' this throat' they inductsecond'ary com bustion air through inlets in the side walls of the incinerator,. and in the expansion chamber thisinducted'air` is utilized? for secondary combustion. of uncombustedl va-v pors and particles carried in; the gas@ stream: The.- encouragement of this secondary combustion inthe expansion chamberI is essential= to: ther minimization ofy oder, which. is caused'for the mosti part bythe emission from .ftheincinerator of uncombust'ed or incompletely combusted gases and microscopic'` particles. ln the expansion chamber, too, the combustion gas stream should somehowbe caused to drop any hy' ash or dust: particles which it may be carrying with it.

ln some instances thefexpansion chamber has heretofore been formedl as aitortuous passage .dened by a-pluralityof balhes, but this type of expansion chamber' had? the disadvantage ofV promoting: and maintaining aI relatively high velocity!flowfof" the combustiongases` throughout their entire passage through the expansion chamber. This followed from the fact' that the passageadened by the baliies was comparatively narrow for its entire length. The gas streamthus necessarily flowed therethrough'f at high velocity canrying; withV it to: the stacl` all: of the y ash and dust particles from the' combustion chamberi .in other incinerators, includingl that ofthe aforesaid copending application, the expansion chamberrprovides a relatively largefunobstructed spaoein whichthe gases' may be substantially decelerated in their flow from the? combustion, chamber to. the smoke outlet and in which they may therefore' drop most of the entrained dustI and liy ash. However, this latter expedient, while satisfactory in some cases, has not always proven to be fully eective, although the incinerator of said copending` application is greatly superior to most previous incinerators with respect to its output of hy ash, dust, visible smoke and odor;

It has now been learned that incinerators ofthe type having an unobstructed expansion chamber have hereto'- fore been unsatisfactory because combustion gases leaving the throat conjointly defined by the' partition wall and drop wall tended to how through the expansion chamber in what might be regarded as three zones. Through the medial portion of the expansion chamber the gases tended to flow in an almost direct line from the throat to the combustion gas outlet, while a' zone of relative stagnation existed at each sideV of the expansion chamben The combustion gases which were thus more or less channeled straight through the medial zone of the expansion chamber naturally constituted the major portion of all of the gases passing through the expansion chamber, and because of their direct how at relatively high velocity the functionV of the expansion chamber was not adequately performed. Naturally, neither' settling of dust and y ash nor complete combustion of odor-causing' vapors and microscopic particles could occur if, the major portion of the combustion gases were channeled at relatively high speed straight through the expansion chamber at the medial zone thereof.

Broa'dly, therefore, i-tV is an object of this invention to provide an incinerator having the' general arrangement described in said copending application and from which there is virtually no emission of y ash, dust, visible smoke orv odor.

More speciically, it is an object of this invention to provide means inan incineratorof the character described for effecting a substantially uniform flow of combustion gases across the width of the expansion chamber whereby all of the gases-flowing therethrough are deflected toward the bottom of the expansion chamber and thus. greatly decelerated, to -thereby promote the necessary fly ash settling` and secondary combustion by which smokeless and odorlessincineration is achieved.

`It has also been learned that to` some extent, the output of smoke, dust andv odor from an incinerator can bocou-- trolled by regulation. of the volume andy length of the: throatV conjointly defined by the partition wall and. drop wall, thatI is, by'providing an optimum spacing between the partition wall and drop wall and an optimum overlap between the bottom ot' the drop wall and the topk of. the partition wall; and it is therefore another specific. objectv of this invention to provide. an incinerator wherein the optimum length of throat is preestablished and wherein( in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate several complete examples of the physical embodiments of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:

Figure l is a longitudinal sectional view through an incinerator embodying the principles of this invention;

Figure 2 is a horizontal sectional view taken on the plane of the line 2-2 in Figure l;

Figure 3 is a vertical cross-sectional view taken on the plane of the line 3--3 in Figure l;

Figure 4 is a view similar to Figure 3 but showing a modified embodiment of the invention;

Figure 5 is a fragmentary longitudinal sectional view, taken on the same plane as Figure l, showing how the drop wall is mounted for adjustment towards and from the partition wall;

Figure 6 is a view similar to Figure 5 but showing a modified embodiment of the invention; and

Figure 7 is a cross-sectional view through the upper rear portion of the incinerator, similar to Figures 3 and 4, but showing another modification of the invention.

Referring now more particularly to the accompanying drawings, in which like numerals designate like parts throughout the several views, the numeral 5 designates generally an incinerator comprising a front wall 6, rear wall 7, top wall 8 and side walls 9. The above identified copending application describes in detail the general arrangement of the incinerator, as well as the construction of the individual modules 10 of which these walls are preferably, but not necessarily, formed,

The interior of the incinerator is divided by a transverse partition wall 11 into a combustion chamber 12, in front of the partition wall, and an expansion chamber 13 behind the partition wall. In the upper rear portion of the incinerator, and preferably centered between the side walls, is a combustion gas outlet 14 which communicates the expansion chamber with a stack (not shown). With the modular construction described in the aforesaid copending application this outlet is conveniently located in the rear wall, near the top thereof, although obviously it could also be situated in the top wall, or even at the upper rear of one of the side walls as at 15 in Figure 7. In any event, practical considerations require the size of the outlet to be such that its major dimension in the direction crosswise of the incinerator, i. e., perpendicular to its side walls 9, is considerably less than the distance between the side walls. Accordingly, the outlet is localized to only a portion of the width of the expansion chamber, being centered with respect thereto in Figures r l to 6 and entirely at one side thereof in Figure 7.

The bottom of the combustion chamber is defined by a grate 16 elevated above the base of the incinerator and onto which the rubbish and other material to be burned is deposited through a charging door 17 which forms the front portion of the top wall. A clean-out door 18 in the front wall permits access to an ashpit 19 below the grate as well as enabling combustion residue to be cleaned oif of the grate itself.

The partition wall 11 extends from one side wall of the incinerator to the other, and its upper free edge is spaced below the top wall of the incinerator to permit combustion gas to ow thereover from the combustion chamber on its way to the expansion chamber. Just before it enters the expansion chamber, and immediately after crossing the upper edge of the partition well, the combustion gas must flow through a narrow throat-20 wherein its rate of flow is abruptly accelerated. lThis throat is conjointly defined by the upper portion of the partition wall and the lower portion of a drop wall 21 which extends across the incinerator from one side wall to the other and depends from the top wall behind the partition wall. The depth of the drop wall is of course greater than the space between the top wall and the free upper edge of the partition wall, so that the free lower edge 22 of the drop wall is disposed below the upper edge of the partition wall. The length of depth of the throat, as defined by the distance the lower edge of the drop wall is spaced below the upper edge of the partition wall, is of major importance in achieving optimum performance. Contrary to what might be expected, it has been found that the length or depth of the throat must be kept fairly short, and for best results the throat length or overlap of partition wall and drop wall should be on the order of 21/2 in. to 4 in., depending upon the size of the incinerator.

As the hot combustion gas iiows at high velocity through the throat 20, secondary combustion air is inducted into it through a pair of air inlets 23, one in each side wall of the incinerator, adjacent to the throat. The combustion gas flowing through the throat along with the inducted secondary combustion air, has a substantial velocity and downward impetus, but immediately after leaving the thoat and entering the relatively large expansion chamber, the gases are rapidly decelerated and thence make their way, at comparatively low velocity, upwardly to the outlet 14, with secondary combustion occurring as the gases thus proceed through the expansion chamber.

To insure adequate deceleration of the combustion gases, the volume of the expansion chamber should be not less than 75% of that of the combustion chamber, and preferably is at least thereof. Moreover, the desirable low velocity flow in the expansion chamber can not be realized if the lower portion of the drop wall extends below the upper edge of the partition wall a distance greater than that indicated, nor can such tlow conditions obtain if the spacing between the drop wall and partition wall is not correct. This spacing, it has been found, should be from about one to three times the mean throat length or depth-i e., one to three times the mean distance which the bottom edge of the drop wall is spaced below the top edge of the partition wall, the exact spacing varying with the type of refuse to be burned in the incinerator and the combustion conditions which normally obtain therein as determined by the type of primary cornbustion fuel employed (gas, oil, etc.), stack height, and other factors which may vary from one installation to another.

In general, the area of the throat, as measured on a horizontal plane intersecting the drop wall and the partition wall, should be about eight percent (8%) of the area of the grate.

To facilitate adjustment and enable the optimum spacing of the drop wall from the partition wall to be readily determined by experimentation, the drop wall preferably comprises a monolithic block of refractory material or the like having downwardly facing shoulders 27 at the ends of its lower face which seat on lengthwise extending ledges 28 in the side walls of the incinerator. These ledges have substantial length to permit considerable forward and backward adjustment of the drop wall as indicatedv in dotted lines in Figure 5.

It will be understood that the thickness of the drop wall is suicient to enable it to remain upright on these r ledges without additional support, and its own weight restrains it against displacement. After the correct location of the drop wall has been found by experiment, it may be readily secured in place with small amounts of mortar, as at 29, to prevent its accidental movement during cleaning of the incinerator.

Maintenance of a uniform flow across the entire width of the expansion chamber is promoted by employing a slightly modified drop wall 21a with a lower edge configuration which tends to discourage combustion gases from channeling straight through the central portion of theA expansion chamber,l ,or taking the shortestl router to the combustion gas out-let. drop wall 21a varies from point to point across the width of the incinerator, with thatportionofV thedrop wall which is nearest the combustion gas out-let beingdeepest. More specifically, where the outlet 14 is centered between the side` walls in the upper rear portion of' the incinerator t (which is the; conventional arrangement and is. depicted in` Figures l-6, inclusive), the lower edge 22a ofi the drop wall 21a is convex, asbest'seen inV Figure 4', being curved on a wide radius to have its, lowest portion 24 substantially midway between the side. walls. However, where installation requirements. necessitate an asymmetrical location of the lcombustion gas outlet, as for example at one side of the top wall (as illustrated at in Figure 7), the bottom of the drop wall must also be asymmetrical.

In the case of the arrangement shown in Figure 7, the drop wall 2lb is substantially quadrilateral, with its lower edge 22h slanting downwardly toward the side of the incinerator at which the outlet is located.

Where the combustion gas outlet is disposed substantially midway between the side walls, and the bottom edge of the drop wall is convex, the curvature of the lower edge of the drop wall need not be very great to obtain the desired results. It has been found adequate, on a drop wall for an incinerator which measures seventeen to eighteen inches between side walls, to have the center of the lower edge of the drop wall about 1% in. below the ends thereof.

In small incinerators, especially, it has been found desirable to use a drop wall having a substantially wedge shaped cross section, as for instance the drop Wall 21e shown in Figure 6, wherein the front surface 26 slants forwardly downwardly at an angle of about 15 to the vertical. This disposition of the front face of the drop wall, together with a convex configuration of the lower edge 22a thereof, defines a throat 20a which is both longest (in the direction of combustion gas liow) and narrowest (as measured from partition wall to drop wall) at a point substantially in a direct front-to-back line with the outlet, thereby eifecting a spreading or redistribution of combustion gases flowing therethrough which not only makes for desirable uniform ow across the entire width of.the expansion chamber but is also highly effective in deflecting combustion gases downwardly into the expansion chamber instead of permitting them to flow directly to the combustion gas outlet.

Actual tests have shown that an incinerator equipped with a drop wall embodying the principles of this invention produces substantially less odor and visible smoke output than previous incinerators operating under comparable conditions, even when the latter were provided with water scrubbing devices or other elaborate and expensive adjuncts for smoke control. With the drop wall located in its optimum position, an incinerator embodying the principles of this invention has been found by actual test to produce such negligible quantities of ily ash, dust and odor that its emissions are normally undetectable by the senses except immediately adjacent to the mouth of the stack.

From the foregoing description, taken together with the accompanying drawings, it will be readily apparent that this invention provides an incinerator which produces little or no smoke, dust, y ash or odor by reason of the provision therein of an inexpensive and simple improved drop wall cooperating with a partition wall to dene a correctly proportioned throat which promotes substantially uniform flow of combustion gases across the eX- pansion chamber, so that all portions of the gas flowing through the expansion chamber are decelerated suticiently to promote adequate secondary combustion and settling of fly ash.

What I claim as my invention is:

1. An incinerator comprising spaced parallel upright Tot-this end theg depth offtheA vextending from one side side walls connected by spaced; uprightfront and rear walls defining; an enclosure; a flat bottom; wall joined to said side front and rear walls; a topY wall joined to said side, front and rear walls,l said top wall being uniformly spaced from the bottom wall upon anyv longitudinal.=` plane parallelV to the side walls and for the. full length of the enclosure;Y an upright partition wallI extending from sidewall to side wall parallel to. the front: and back walls andspacedL therefromI to. divide;- the enclosure into a combustion chamber at the front and an expansion chamber at the` rear thereof, the upper. edge of the partition wall being spaced from the, top, wall; a gratel inthe lower portion, ofl the comhustionchamber; a. charging door in the top wall above the grate through which refuse to be burned may be deposited in the combustion chamber; opposite horizontal ledges on the side walls extending lengthwise thereof behind the partition wall; a drop wall having the ends thereof seated upon said ledges so that the position thereof with respect to the partition wall is readily adjustable, said drop wall extending from side wall to side wall and having its top edge contiguous to the top Wall and its bottom edge at an elevation below the top of the partition wall, the horizontal distance between the partition wall and the drop wall being substantially between one and three times the average distance the bottom edge of the drop wall is spaced below the top edge of the partition Wall so that combustion gases and products of combustion passing from the combustion chamber into the expansion chamber are caused to flow downwardly along the rear of the partition wall to the bottom of the expansion chamber; and means cinerator.

2. An incinerator having front, rear, side and top walls, a partition wall intermediate the front and rear walls and wall to the other with its free top edge spaced below the top wall, dividing the incinerator into a combustion chamber in the front of the incinerator and an expansion chamber at the rear thereof, the expansion chamber having a combustion gas outlet in its upper portion, said incinerator being characterized by: the fact that the combustion gas outlet is of such size and is so located that its major dimension in the direction perpendicular to the side walls is considerably less than the distance between the side walls; by the provision of a drop wall spaced behind the partition wall and extending from one side wall to the other, said drop wall projecting downwardly from the top wall and having its free lower edge spaced below the free top edge of the partition wall, and being spaced rearwardly of the partition wall wall a distance between one and three times the average distancethe free lower edge of the drop wall is spaced below the free top edge of the partition wall, so that the drop wall and the partition wall cooperate to define a narrow throat extending across the width of the incinerator through which combustion gases from the combustion chamber enter the expansion chamber; and further characterized by the fact that said free edges of the drop wall and the partition wall are non-parallel across the full width of the expansion chamber.

3. The incinerator of claim 2 further characterized by the fact that the combustion gas outlet is substantially centered between the side walls so that its laterally opposite side edges are spaced a substantial distance from the adjacent side walls; and further characterized by the fact that the non-parallel relationship between the free cinerator.

6. The incinerator of claim 2 further characterized by the provision of means mounting the drop wall for bodily adjustment thereof toward and from the partition wall so that the size of the throat defined therebetween may be varied to suit local combustion conditions.

References Cited in the file of this patent UNITED STATES PATENTS Jones Apr. 12, 1887 Broman Mar. 27, 1917 Saha Apr. l5, 1930 Knobloch Nov. 2, 1948 FOREIGN PATENTS Germany July l5, 1893 Great Britain of 1901

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