US1991986A - Incineration - Google Patents

Description

Feb. 19, h1935. D, SHEMWELL, ET AL 1,991,986'

INCINERATION Filed Sept. 30', 1931 4 Sheets-Sheet 1 ////v Q w s l VJ Feb. 19, 1935. D, SHEMWELL ET AL 1,991,986

INCINERATION Filed Sept. 50, 1931 4 Sheets-Sheet 2 HIT l l I L IL: 1| I wf Val QX o Feb. 19, 1935.

D. sHEMwELL Er A1.

INCINERATION Filed Sept. 30, 1951 4 Sheets-Sheet 4 Patented rFeb. 19, i935 l1,su1,9as

yINCINERATION l Dermot Shemwell, Lexington,` and Rayburn Stokes Webb, Winston-Salem, N. C., assignors,

by mesne assignments, to Decarie Incinerator Corporation, New York, N. Y., a corporation of A New York Application September 30, 1931, Serial No.`566,006v

3 Claims.

Our invention relates to incineratorsfor burning garbage, refuse and the like and` relates vboth to apparatus and method of operation thereof.

The `principal object of our invention is to improve'combustion in an incinerator so as to` provide complete combustion with yodorless. exit gases and without Vhaving excessive operating temperatures.- Our invention, in its more specific applications, relates ,to Vincinerators of the-type including a primary furnace chamber and a passageway connected thereto, in which. passageway combustion is carriedV on Vto the ultimate capability of theincinerator. In this type'of furnace, the temperature of the primary furnace chamber in' the past hasv seldom been as high as 900 F., ,whereas temperatures in the passageway leading therefrom have risen to 1,800" F. and higher. Also there have been temperature flashes of extremely high temperature in such passageways. These high temperatures have a deleterious effect .on the brickwcrkl of the furnace. Y

In accordance with the present invention, we propose to'alter the combustion process by raising -the temperature of the primary furnace chamber and lowering the temperaturein such `passageway leading from the Vprimary furnace chamber relativeto past practice. In accordance withlthe invention,Y we introducefresh'fcold air into the passageway leading from the Vprimary furnace chamber.` The manner in which this is done serves a three-foldl purpcsefynthe .first place, it provides cold `air for direct cooling fof the products of combustion; that' is, relative to `furnaces ofthe prior type which do not introduce cold air.' In the second place,l it provides oxygen contained in the `air for secondary combustion, making the passageway a truersecondarycombustion chamber. And, in the third place, it serves to agitate the iiow of-product's ofV combustion between-the stages of-primary and secondary combustion.

One feature of our invention consists in intensiyng the combustion "in, the yprimary combustion chamber by the formation of ,reflecting surfaces, `as will be hereinafter more fully explained. y v

The,` above and other objects of the invention will be made clearV as the more detailed descrip- .tion proceeds, which description is Htcbe taken in, connection with the accompanying drawings showing a preferred form of incinerator embodying the invention, and which drawings are to be taken as part. of this specication, it lbeing understood, however, that the. invention, and separately, the component features thereof, may be applied to a variety of structures, the .invention being limited only by the claims hereof construed in the light of the prior art. y f i Referring to the accompanying drawings: Fig. 1 is a longitudinal vertical sectional view of our improved incinerator taken on the lin 1 1 of Figs. 3 and 6; i

Fig. 2 is an external elevational View of the improved incinerator; i

Fig. 3 is a plan view of part of the incineratpr takenon the line 3 3 of Fig. 1;

Fig. 4 isl a transverse vertical sectional view taken on Ythe line 4 4 of Fig. 1;

Fig. 5 is a partial vertical sectional view taken on the line 5 5 of Fig. 3;

Fig. 6 ris a horizontal sectional view taken on the line 6 6 of Fig. 1;

Fig. '7 is a transverse vertical cross-sectional View taken on the line '7 7 of Figs. 1 and 6;

Fig. 8 is a vertical transverse sectional Vview taken on the line 8.-8 ofFigs. 1 and 6'; and

Fig. 9 isga. transverse verticalA sectional view taken on theline 9 9 of-Figs. 1 `and 6. The incinerator, designated generally atg10,

iincludesa primary furnace or combustion chamber 11, a secondary combustion chamber, or pasf sageway 12and a iiue 13` which may be con- Anected to a chimney or stack.

Y A-The primary furnacelchamber `ll'is Vformed by side wallstructure 14 and an arched roof 15. As

4isshown in Fig..3, the chamber ris essentially of `the circular type, the surrounding side wall structure being essentially of the form of a regular polygon.' The side wall structure '14 is advantageously formed of outer steelwcrk 16 (see Fig. 3) within which there is'a course of brick 17, then insulation 18 of suitable type such as asbestos base,` andthen a course of fire-brick 19 :on the inside. Openings Y20 are provided at various points in the side wall structuraand these may be suitably closed by counterweighted guillotine type .doors 21. The arched roof`15 `ofthe primary combustion chamber may be made'up in the same manner. In the center Aof the roof is a charging or inlet chute 22 having a cover23 preferably about flush with an upper floor 24'...

The primary furnace chamber 11 preferably has a strictly horizontal oor 25 made up principally of grates. The grates are supported on brickwork 26, which brickwork comprises several walls below the primary furnace chamber and withinv the ash pit 27. As shown more ind'etail in Fig. 3, the grates comprise a central longitudinally extending set 28, dumping grates 29-in front of the doors which may be suitably pivoted in any desired manner and intermediate oddshaped grates 30. The grates are so fashioned as to permit passage of air therethrough. Ash doors 31 are provided below each furnace door 21 giving access to the ash pit under the grates. The furnace floor is continued horizontally back of the grates by a brick floor 32 (see Fig. 1) on the same level as the grates and also horizontal.

At what may be termed the rear of the furnace chamber, two openings 33 connect with the secondary combustion chamber 12. A supporting pillar 34 is positioned between the openings 33. This pillar extends down to the foundation. l

The side walls 35 of the secondary combustion chamber 11 are vertical and straight and parallel. Within the secondary combustion chamber is a baffle bridge wall 36 beyond which there is a drop substantially to the foundation level, as shown at 37 in Fig. 1. The baille wall is about one-half-as high' as the openings 33, as clearly appearsin Fig. 1. It extends transversely of the secondary combustion chamber. The bricks are so laid as to provide openings 38.

Ahead of the baffle wall 36 are airducts 40.

` As shown more particularly in Fig. 4, these ducts are imbedded in the side walls. Cold air is admitted at the top of each air duct 40 and enters the secondary combustion chamber adjacent the iioor at 41. Theducts may be made up of cast iron sections. It will be evident that the air thus introduced will be relatively cool as compared with the air admitted through the openings 42 (Fig. 6). It will be understoodk that the draft caused by the chimney or other means draws the air into the secondary combustion chamber. The line of admission of the air is transverse to the longitudinal direction of the gas pass in general. Y

Below the floor and at 42 is an air inlet. Preferably this air comes from an air preheater indicated at 43 in Fig. 6. In certain cases, however, the air preheater maybe omitted; The airis distributed under the furnace floor and passes upwardly through the grates. Openings are provided in the members 26 as at y44 so that the air may have access to underneath all the grates.

VIn accordance with the invention, we have madeV reflecting niches 45 in the side wall structure of the primary furnace chamber 11. There are two rows of niches, one in the lower part of the chamber, and oneinthe upper part of the chamber.' A greater number may be used if desirable. These niches are formed by continuing alternate walls straight towards eachother, as indicated at 46 in Fig. 3. This continuation of the straight surface is angular as shown in Fig. 1. The shape of the niche is clearly apparent from Fig. 5. It will be evident thatl either one row of niches or two rows will constitute reflecting means extending around the periphery of the primary furnace chamber.

In operation of the device, garbage or other material Vto be burned is dumped through the inlet chute 22 and forms as a pile on the floor of the furnace chamber. Suitable steps are taken to rignite the pile of refuse as by the `burning of coal, coke or the like. As is understood, inthe case of wet refuse itmay be advisable to add coal through the openings 20 while the combustion is'taking place. Air passes 'from opening 42 and into the ash pit. This air may be preheated in a separate preheater or it may be passed through the Walls of the incinerator. The

hot air passes uptlirough the grates and supplies the oxygen for combustion. The refuse is burned and the products of combustion, due to the suction, are drawn through the passages 33 and through the secondary combustion chamber and to the stack.

If desired, and preferably, an air fan'is provided for supplying air under pressure to opening 42. It is particularly desirable to have mechanical means for causing flow of air in starting the apparatus.

When combustion is well under way, there is a a result ofwhich it solidifies and adheres to the wall. We propose to use this feature in forming reflecting surfaces. deposit in the irregular surfaces ofthe niches 45 and will smooth out the corners and form ay smooth surface concave reflector as indicated at 47 in Fig. 5. These reflectors 47 thus formed by natural slag formation will cause radiant heat` rays from the nre to converge on more or less the same principle as a parabolic reflector. This will concentrate heat in the mass of burningkmaterial and assist combustion. We provide the circular furnace totake advantage of the reec' tion of radiant heat and in addition provide the reflectors 45-47 to intensify the combustion by the reflection and concentration of radiant heat rays.

Products of combustion leaving the primary furnace chamber 11 pass through the passages 33 and flow towards the baille bridge Vwall 36. The baffle bridge wall 'being interposed in the path of flow along the lower part of the structure causes an eddy in front of the same, as shown by arrows in Fig. 1. This serves to agitate the products of combustion and break up' particles carried into the combustion gases. Furthermore, the bridge wall 36 itself provides an obstruction to solid mater in the gases and aids in obtaining complete combustion. Y Y

Into thespace Where the eddy is thus formed we inject relatively cool air transversely. y Since the eddy is circular as indicated, in Fig. 1, and

The fluxible particles will Y the air admitted passes transversely to the general line of flow, there will be complete agitation,

of the air. This agitation is important because in certain constructions it has been found that temporary flashes of high temperature take place and that the temperature is not uniform. This may be due to non-uniformity of the products of combustion, certain portions of the gases being more readily combustible than other portions. By thoroughly agitating the air, as is done by the present invention, this non-uniformity of the gas mixture is avoided and the operation in the secondary combustion 'chamber is made more uniform.

The secondary combustion chamber beyond the bridgewall 36 being enlarged, there is a certain amount of expansion in the products of combus tion which further results in eddying and the obtaining of complete burning of al1 the prod- Y obtained with temperatures anywhere within a.

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relatively large range. In most cases, a temperature of 1,300 F. is fully as good as a temperature of 1,800 F. The higher the temperature, the greater the wear on the furnace Wall structure. High temperatures are disadvantageous both from point of View of abrasion and distortion due to expansion and contraction. Prior furnaces have rarely operated with over 700 F. in the primary furnace chamber,y and the temperature of the products of combustion increases to very high values in the secondary combustion chamber. Our aim has therefore been to increase the temperature in the primary combustion chamber and to hold down the temperature in the secondary combustion chamber. As a factor in increasing the temperature in the primary furnace chamber, We propose to use reflecting surfaces as above described, and to use air which is preferably heated to a greater or less extent. Before the secondary stage of combustion, name'- ly, that in the secondary combustion chamber, we introduce relatively cool air. This might be Ythought oifhand to have an adverse effect upon combustion. However, in accordance with our theory, we wish to keep down the temperature in the secondary combustion chamber, and therefore we supply cold air. l By means of the joint action of the various features hereinabove described, we are ablek to increase the temperature in the primary furnace chamber and decrease the temperature in the secondary combustion chamber relative to past practice. Furthermore, we obtain an improved completeness of combustion.

Having thus described our invention, what We claim is:

1. An incinerator comprising a refuse-receiving primary combustion chamber, an outlet flue, a secondary combustion chamber between said primary combustion chamber and said flue, said secondary chamber having straight parallel side Walls and a floor with a raised portion at the entrance end of theV chamber, a baie wall transversely of said secondary combustion chamber and at the end of the raised portion of the floor, and upright .air flues within said side walls receiving air through their upper ends and having at their lower ends openings for admitting air into said secondary combustion chamber angularly With respect to said side walls just above the raised portion of the floor and in front of said baille Wall.

2. An incinerator comprising a refuse-receiving primary combustion chamber, an outlet iiue, a secondary combustion chamber between said primary combustion chamber and said flue, said secondary combustion chamber having at itsl entrance a portion of its floor in raised elevation, means for admitting air to said primary combustion chamber, and means admitting air to said secondary combustion chamber in two oppositely directed streams from opposite sides of said secondary combustion chamber and just above the upper surface of said raised portion of the floor.

3. An incinerator comprising a refuse-receiving primary combustion chamber, a refuse-supporting grate in the lower part of said chamber, an outlet iiue, a secondary combustion chamber between said primary combustion chamber and said ue, said secondary chamber having parallel side Walls throughout its length and having a portion or its floor in raised elevation at the entrance and at substantially the level of the grate in said primary combustion chamber and the remainder of its floor at a substantially lower level, a baiiie wall projecting upwardly froml the raised portion of the floor, and means for reducing upward surges of temperature in said secondary combustion chamber consisting of upright flues at the sides of the secondary combustion chamber receiving outside air at their upper ends and discharging the same into the secondary combustion chamber substantially at the upper surface of the raised portion of the oor.

DERMOT SHEMWELL.- RAYBURN` S. WEBB.

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