Патент USA US2115337код для вставки
April 26, 1938. G, R LEwERs ' 2,115,337 INCINERATION Filed Dec. 4, 1936 / /// ///// // INVENTOR GEO RGE R. LEWERS ' ,2”; ATTORNEY Patented Apr. 26, 1938 2,115,337 UNITED STATES PATENT OFFICE 2,115,337 INCINERATION George R. Lewers, Brooklyn, N. Y., assignor, by mesne assignments, to Underpinning & Foun dation Company, Inc., New York, N. Y., a cor poration of New York Application December 4, 1936, Serial No. 114,124 9 Claims. This invention relates to incineration and more particularly to improvements in tiered multiple hearth furnaces and to improvements in process es for drying and burning material bypassing it of: -? downwardly through a plurality of zones, gradu ally drying it in upper zones and then burning it in lower zones. . Although the apparatus and process of the ‘ _ present invention are suitable for use with many it) kinds of material, they are of particular value in drying and burning waste material such as gar bage and sewage material including sewage sludge and sewage screenings bothof which have ‘ a substantial moisture content. The principal objects of the invention are to as a heat exchanger and the air passing there through is heated, to some extent before being discharged into the furnace. The present inven tion contemplates a greater heating of the air 5 before it is discharged into the furnace. In car rying out this feature of the invention, direct ?ow of air through the hollow shaft may be shut off by a suitable obstruction and the air may be by-passed around the obstruction through a suit- 10:" able heat exchanger carried by the shaft. The heat exchanger may consist of an inlet chamber or duct surrounding the shaft and communicat ing with the interior of the shaft below the ob struction, a discharge chamber or duct surround- 1B3 ing the shaft and communicating with the inte ratus and processes for treatment of material of rior of the shaft above the obstruction, and a plurality of ducts or tubes- parallel to the shaft and connecting the inlet and discharge chambers. the general character speci?ed. Another object treatment is passed downwardly through a plu rality of drying zones and then through a plu rality of burning zones. A further object relates ' to improvements in the heating within a multi Other objects, features and advantages will ap pear upon consideration of the following detailed description and of the drawing in which the ?gure is a view in vertical'section of apparatus embodying a preferred form of the invention. be embodied in a furnace I0 provided with a top The invention may be carried out in connec tion with a multiple-hearth furnace divided into the hearth ll serves as a bottom of the furnace or an upper drying section and a lower burning sec tion by an intermediate hearth having a gas seal through which the solids are fed in correspond rabbling devices supported and operated by a hol 55 low vertical shaft. A current of heated air may be passed through the drying zones in contact with the material on the various hearths and then laden with vapors of moisture and volatile substances may be discharged therefrom. Ordi iill' narily the air thus laden with vapors would be passed, either with or without reheating, into the burning section of the furnace. According to the present invention, however, vapors mixed with l the air are condensed and removed before the air 45" is introduced into the burning section. _ ‘ The air to be introduced into the drying sec tion of the furnace may be supplied through a hollow vertical shaft used in operating rabbling devices whereby the solid material on the vari ous hearths is agitated and fed to the outlets thereof for passage downwardly through the fur nace. Heretofore air supplied to the lower end of a shaft of this kind has been conducted direct ly through the hollow shaft to a desired point and 55 then discharged through an outlet or nozzle into 20 Referring to the drawing, the invention may 2'5" ple-hearth furnace of air supplied to the furnace. ence with the downward discharge through the other hearths due, for example, to the action of ’ a compartment of the furnace. The shaft serves provide novel and advantageous forms of appa relates to the condensation and removal of vapors from the gases passing from the drying zones to the burning zones where the material under P10 ‘; (Cl. 110-12) H and hearths I2, [3, l4, l5, I6 and ll, of which furnace chamber. The material to be treated may be introduced 30'? into the furnace and deposited ‘upon the upper most hearth l2 through a hopper l8 and a chute l9 extending through the top H of the furnace and provided with a pivoted door or gate 20 nor mally held closed by suitable means such as a 357‘ weighted arm 2|. As soon as a sufficient amount of material to overcome the action of the weighted arm 2| collects on the door or gate 28, the door swings downwardly about its pivotal support and permits the material on the door to 40‘ fall to the hearth l2. 7 As illustrated, this material falls on the hearth [2 near its periphery and is worked inwardly. to a central discharge opening 22 by suitable rabbling 45 means including one or more radial arms 23 and inclined blades 24 carried thereby. Below the hearth l2,'the hearths l3 and 15 are provided with peripheral outlets 25, the hearths l4 and it are providedrwith central outlets 22 corre sponding with the central outlet of the hearth l2, and the lower hearth I‘! is provided with a single outlet or chute 26 through which the ash is discharged from the furnace. The chute 25 is preferably provided with a gas seal in theform 55 .7217 7 2,115,337 . of a pivoted door 21 normally ‘held in closed po sition by a weighted arm 28. The material on' the hearths'rl3, |4, |5, l6 and‘ ' I1 is moved towards the corresponding outlets by suitable rabbling means similar to that used above the hearth |2, the blades 28 above the modate a heat ‘exchanger of desired capacity. It mayrtherefore be convenient to utilize two com- I partments of the burning section by arranging forthe heat exchange to pass through the cen- . tral outlet of a hearth having this type of outlet. 7 As herein, disclosed, the heat exchanger 42 ex-, hearths l3, I5 and I‘! being so inclined as to carry tends through the hearth I4 of which the central the material outwardly to thel'peripheral outlets ‘ outlet is madelarger for this purpose. The re-' quirement for space may also be met by spacing thereof,'a_nd the blades aboverthe hearths I4 and _ certain hearths farther apart, thus providing lot 10 H5 being so inclined as to work the material to ' higher compartments. As shown on the drawing, 'ward the central opening as in the case of hearth . the compartment above the hearth I5 is of great 12. ' a i ' . ' ' ' , ~ ' , The rabbling arms 23 ‘may be supported and er height'than the other compartments. The air supplied to-the uppermostcompart operated» by a hollow vertical shaft 29 passing 15. 15 through the central parts 'of'the central outlets ‘ment orzone of the‘ drying section may be passed 22' of the hearths |2, |4 andfl? and through small downwardly through the section, that isconcur openings in the top | | and the hearths |3, J5 and rently with the flow of the solids, anddischarged ' a‘ IT,’ suitable gas seals being. provided Where the from thelowermost'drying compartment through ' ' ' shaft 29 passes through the top, and these; a duct 41 to a condenser 48. . This condenser may The shaft 29 may be rotated inany 7207 hearths. suitable manner as by'meansof a'bevel gear 30 ' thereon, abevel gear 3| ,meshingwith the. bevel comprise a chamber 49 with a drainage sump at ,its bottom discharging through'a drain or drain pipe 50, and arpipe system; or coil 5| in the cham gear 30, and'a' pulley 32 connected with the bevel ber connected at one end with ,a supply pipe 52 r‘ gear 3| and driven‘ from any’ suitable source of . and discharging; at the other end'into thesump at the "bottom of the chamber 49, the condensate 25 The furnace may be divided intoj‘an' upper or and condenser water ?owing away together drying'section and alower burning section by the ' through the drain 50.‘ The liquid discharged: ' 25 power. » hearth I3 which‘preferably'has but one outlet through the drain 50 may be carried away with ‘ 25 ‘provided with a’ valvev or , gas seal through the ‘sewage ?ltrate resulting from a preliminary '30 which thefsolid material may be fed while an dewatering of the sewage sludge, or may be re effective gas seal is maintained.~ Although this turned to. the sewage stream before it reaches’ valve may take different forms, thatzdisclosedp ‘the ?lter. In this connection attention may be comprises a’ tube343i in said outlet ‘25, a conical called to the high moisture content of the sewage " valve for valve member 34 adapted. to. cooperate‘ ' sludge fedto the furnace and the resulting large with the lowerendfof the tube “and urged‘to, "closing position j by,’ suitable , means which 1 may comprise a lever 35 pivoted at 36 and having a pivotal connection with the valve member .34. 7 volume of water vapor?owing out of the drying . section with the air stream. Obviously there will be a. large amount of liquid‘ condensedrin the. condenser. I " . ' The lever 35' passes through the side "of the tube ,133 and through the wall of the furnace,.the outer From- the condenser, the/relatively dry’ air is ‘passed through a duct. 53jto the burning section, 40 “ arm being urged downwardly byv a weight 31. vpreferably into the V lowermost, compartment Division of the furnace in this way renders pos sible better control of the ?ow of airrandigases. The air and hot combustion gases ?ow up through the various parts of the furnace. , wardly through the burning section and'are dis Air may be supplied to the drying section 7 charged therefrom, preferably from the upper-' I; through the hollow shaft 29, to the lower part of most compartment, through‘ a duct 54, which which air may be supplied by a fan 38 and con may lead through a suction fan to a stack. ' ' ,necting duct 39. _The air passing upthrough the Obviously the number of'hearths' in thedrying , V furnace in the hollow shaft. will be heated by; and burning‘sections may be varied. For use in thereof. _ l V , heat exchange with the contents of the burning , starting and whenever‘needed, the gvariousrcom zones and in this preheated condition may be partments or zones may be provided with'burners discharged into theupper partlof the drying sec-j '54 and doors 55." " ' " ‘ ' ' tion through oneor more outlets or nozzles 40. 7 It should be understood that various changes’ ,Heretofore, the air has been passed through the 'vmay be'made and that certain features may be hollow shaft from an inlet to an outlet. . '55; - In the present instance, itfis desired to utilize the heat from the burninglmate'rial in the burn-, - ing zones to raise the temperature to’ahigher V . level. . To thisendLdir'ect flow of the air through " gm. used without others without" departing'from the true scope and spirit of the invention. 5 the, hollow shaft may be prevented by. providing , the'hollow shaft at 'a suitable point withian ob struction or dam 4| to shut off the flow and divert the stream through 'a heat‘ exchanger 42 carried Having thus/described my invention,‘I claim: _ -,1. In combination mm a tiered multiple hearth? furnace divided into adryi'ng section and a burning sectio-nby a hearth having a gas sear ' through which solid material may be fed, means. for supplying airfto the‘ drying section, and means , 5 by the shaft; This heat exchanger may be of the “for discharging hot combustion gases’from'v the l‘ duct or pipe type andcomprise a lower hollow btu'ning section, a condenser and means for with ring 43 communicating with‘ the interior of the ' drawingairladen with vapors fromlthe drying shaft’ 29 below thedam-M through'one or'more' section and passing it through said condenser to the burning section. ' ' ‘r connections 44, an upper hollow ring 45 com municating with the interior of the shaft;29 ' 2. In combination with a 1 tiered multiple hearth furnace divided into a drying section and abovethe dam 4| through one or more connec tions 46.* Hot gases, of combustion, mayv engage , a burning section by a hearth having a gas seal" the ducts-of the heat exchanger 42 at vall sides through which solid ‘material may be fed, means 70-" and provide effective heat“ exchange. 7 j p. The usual compartment over. a burninghearth ‘I 15": would for supplying air to upperrpart of the drying sec- . f tion, and means for discharging hot combustion" not ordinarily’be high enough to aecom- ' gases from the burning section, a condenser and u 2,115,337 3 means for withdrawing air laden with vapors from the lower part of the drying section' and pass ing it through said condenser to the burning sec shaft and by-passing air around the blocking tion. 3. In combination with a tiered multiple hearth furnace divided into a drying section and hearth furnace comprising upper dryingcom partments' and lower burning compartments, and 5 a burning section by a hearth having a gas seal through which solid material may be fed, means for supplying air to the drying section, and means 10 for discharging hot combustion gases from the upper part of the burning section, a condenser and means for withdrawing air laden with vapors from the drying section and passing it through said condenser to the lower part of the burn 15 ing section. 4. In combination with a tiered multiple hearth furnace divided into a drying section and a burning section by a hearth having a gas seal through which solid material may be fed, means 20 for supplying air to the drying section, and. means for discharging hot combustion gases from the burning section, a condenser and means for with drawing air laden with vapors from the drying section and passing it through said condenser to 26 the burning section, said condenser comprising a chamber through which the air passes, said chamber having a drainage outlet for condensed ‘ moisture, and a water duct passing through said chamber to condense moisture carried by the air 30 and discharging through said drainage outlet with said condensed moisture. 5. In combination with a ‘ tiered multiple hearth furnace comprising upper drying compart ments and lower burning compartments, and a 35 hollow shaft supplied with air at its lower part and discharging air into a drying compartment, means for blocking the passage of air through a part of said shaft in the burning zones and a heat exchanger surrounding said shaft and by passing air around the blocking means. 6. In combination with a tiered multiple hearth furnace comprising upper drying compart ments and lower burning compartments, and a hollow shaft supplied with air at its lower part 45 and discharging air into a drying compartment, means for blocking the passage of air through a part of said shaft in the burning zones and a multiple duct heat exchanger surrounding said means. . . 7. In combination with a tiered multiple a hollow shaft supplied with air at its lower part and discharging air into a drying compartment, means for blocking the passage of air through a part of said shaft in the burning zones and a heat’ exchanger surroundingsaid shaft and ‘by-passing 10 air around the blocking means, said heat ex changer comprising a duct surrounding said shaft and communicating with its interior below the blocking means, a second duct surrounding said shaft and communicating with its interior above the blocking means and a plurality of ducts con necting the ?rst and second mentioned ducts. 8. In combination with a tiered multiple hearth furnace comprising upper drying compart ments and lower burning compartments, and a 20 hollow shaft supplied with air at its lower part and discharging air into a drying compartment, means for blocking the passage of air through a part of said shaft in the burning zones and a heat exchanger surrounding said shaft and by 25 passing air around the blocking means, said heat exchanger comprising a duct surrounding said shaft but spaced therefrom and communicating with its interior below the blocking means, a second duct surrounding said shaft but spaced 30 therefrom and communicating with its interior above the blocking means and a plurality of ducts connecting the ?rst and second mentioned ducts. 9. In combination vwith a tiered multiple hearth furnace in which the hearths are provided 35 alternately with central and peripheral outlets for downward passage of the solids under treatment, and a central hollow shaft receiving air at its lower part and discharging it into the furnace above an upper hearth, said shaft passing through 40 the central parts of the central outlets of alter nate hearths and with gas-seal connections through the other hearths, a heat exchanger sur rounding said shaft and extending through one of said central outlets, and means for passing 45 through the heat exchanger air supplied through said hollow shaft. GEORGE R. LEW'ERS.