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Publication numberUS3267890 A
Publication typeGrant
Publication dateAug 23, 1966
Filing dateApr 19, 1963
Priority dateApr 19, 1963
Publication numberUS 3267890 A, US 3267890A, US-A-3267890, US3267890 A, US3267890A
InventorsRobert E Zinn, Thomas J Lamb
Original AssigneeLittle Inc A
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Municipal incinerator
US 3267890 A
Abstract  available in
Images(7)
Previous page
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Claims  available in
Description  (OCR text may contain errors)

R. E. ZINN ETAL MUNICIPAL INCINERATOR Aug. 23, 1966 '7 Sheets-Sheet l Filed April 19, 1963 Aug.`2`3, 1966 R. E. zINN r-:TAL 3,267,890

MUNICIPAL INCINERATORv Filed April 19. 1963 7 Sheets-Sheet 2 Robert E. Zinn Thomas J. Lomb INVENTORS BY/M/ Attorney Aug. 23, 1966 R. E. zlNN ETAL 3,267,890

MUNICIPAL INCINERATOR Filed April 19, 1963 7 Sheets-Sheet 5 Rober? E. Zinn Thomas J. Lomb INVENTORS wkn/WW Attorney Aug. 23, 1966 R. E. zlNN ETAL 3,267,890

MUNICIPAL INCINERATOR Filed April 19, 1963 v 7 sheets-sheet 4 Robert E. Zinn Thomcls J. Lomb INVENTORS Aorney Aug- 23, 1966 R. E. zlNN ETAL 3,267,890

MUNICIPAL INCINERATOR Filed April 19, 1953 7 Sheets-Sheet 5 Robert E. Zinn Thomas J. Lomb INVENTORS Attorney R. E. ZINN ETAL MUNICIPAL INCINERATOR Aug. 23, 1966 Filed April 19, 1963 '7 Sheets-Sheet Attorney Aug- 23, 1966 4 R. E. zlNN ETAL 3,267,890

MUNICIPAL INCINERATOR Filed April 19, 1963 7 Sheets-Sheet '7 Robert E. Zinn Thomcls J. Lclmb INVENTORS BY /w'4 /Wm,

Atorney United States Patent O 3,267,890 MUNICIPAL INCINERATOR Robert E. Zinn and Thomas J. Lamb, Lexington, Mass., assignors to Arthur D. Little, Inc., Cambridge, Mass., a corporation of Massachusetts Filed Apr. 19, 1963, Ser. No. 274,202 Claims. (Cl. 11G-18) This invention relates to incinerators and more particularly to incinerators suitable for handling the refuse of a municipality.

With the ever-increasing number of strict municipal ordinances concerned with the disposal of refuse, communities of all sizes are being forced into the use of completely enclosed incinerators to take the place of the opendump type of burning -to dispose of such refuse. Moreover, with the ever-increasing realization of the possible harmful effects that particulate matter and combustion gases emitted in the air may have on the populace, such incinerators must be capable of burning refuse without adding to the contaminants in the air. Thus cities and communities are faced with providing eihcient systems of incineration. It is of course most desirable that such incinerators be economical to build, maintain and operate.

The apparatus of this invention is designed to meet these requirements and to provide an incinerator which is economical, eicient, freel from possible health hazards, and exible in its adaptation to cities and communities of widely varying size and needs.

It is, therefore, a primary yobject of this invention to provide apparatus suitable for completely and efficiently burning the refuse of a community. It is another object of this invention to provide apparatus of the character described which is economical to build, maintain and operate. It is yet another object of this invention to provide an incinerator or incinerating system which achieves combustion of both solid materials and volatiles to such an extent tha-t there are no hazardous components introduced into the surrounding atmosphere. It is an additional object -of this invention to provide apparatus of this character which is flexible in its arrangement of parts and in size to make it readily adaptable to widely varying community populations. Other objeots of the invention will in part be obvious and will in part be apparent hereinafter.

The 4invention accordingly comprises the features of construction, combinations of ele-ments and arrangements of parts which may be eXempliiied in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims.

In general, the incinerator of this invention comprises one or more horizontal, cylindrical primary combustion chambers designed to burn substantially all of the solid. combustible material, Ione or more horizontal, cylindrical secondary combustion chambers designed to burn volatiles and light weight solids carried in said volatiles which are transmitted from the primary com-bustion chamber or chambers, means for preheating combustion air and means for removing the unburned solids as ashes or ily ash without interrupting the combustion process 4and without introducing any contaminants into the surrounding air. The combustion chambers are so constructed as to require inexpensive ordinary rebrick linings and to eliminate the need for thermal insulation.

In modifications of the incinerator the secondary combustion chamber may be combined with the primary combustion chamber; and the means for preheating the combustion air may be omitted, in which case the steel shells forming the combustion chambers are cooled by radiation and natural convection `to the atmosphere.

For a fuller understanding of the nature and objects 3,267,890 Patented August 23, 1966 of the invention, reference should. be had to the following detailed description taken in connection with the accompanying drawings in which:

FIG. l is an overall schematic representation of the incinera-tor of this invention showing the components and controls;

FIG. 2 is a side elevational view of the incinerator;

FIG. 3 is a cross-sectional view of the primary combustion chamber along line 3 3 of FIG. 2;

FIG. 4 is a cross-sectional View of the primary and secondary combustion chambers along line 4 4 of FIG. 2;

FIG. 5 is a side elevational view partially cut away, of a modification of the primary combustion chamber;

FIG. 6 is a cross-section along line 6 6 of FIG. 5;

FIG. 7 is a cross-sectional view of the secondary combustion chamber along '7 7 of FIG. 4;

FIG. 8 is an end elevational view of the incinerator;

FIG. 9 is a cross-sectional view of the secondary combustion chamber and scrubber along line 9 9 of FIG. 8; and

FIG. 10 is a top plan view of the incinerator.

The complete incnerator FIG. l is a schematic diagram of the components making up the incinerator 4of this invention. It will be help- -ful first lto identify these components in FIG. l, and then to `discuss each of them in detail with reference to subsequent figures.

Turning now to FIG. 1, it will 'be seen that there is provided an essentially horizontal cylindrical pri-mary combustion chamber 10 designed to volatilize and burn the solid materials, a horizontal cylindrical secondary combustion chamber 12 designed to -burn the gaseous or volatile materials, and a conduit 13 which joins these combustion chambers. As described below, these two combustion chambers may be combined. The primary combustion chamber is equipped at its inlet or forward end wit-h a charging hopper 15 vwhich leads into a charging gate 16 and into a refuse inlet -conduit 17 which conducts the material to "be burned into the primary combustion chamber 10. Alternatively, the charging gate 16 may be omitted and gravity feed means used 'as illustrated in FIG. 5 and described below. At its outlet or after end the primary com'bustion chamber has an ash outlet conduit 20 which in turn is controlled by an ash gate 21 and which deposits the ashes int-o an ash hopper 22. This arrangement for withdrawing ashes permits changing ash receptacles without changing the draft or pressure in the combustion chamber.

Material to lbe burned is delivered to the primary combustion chamber by any suitable means, that sho-wn in FIG. 1 consisting of a bucket 25 s-uspended on a travellirng crane 26 through appropriate suspension `cables 27. The crane in turn is moved on suitable rail 28. Any other suitable device suc'h as a skip hoist m-ay be used to deposit the material to be burned into the charging hopper 1'5. Since it is desirable to be able to lensure` t-he removal of all of the ashes from the combustion chamber, particularly those which fall through the grates, means are provided for transporting these ashes along to the ash hopper. This may Ibe accomplished by ushing the ashes along with water or by carrying them with a suit-able travelling conveyor. In FIG. 1 it will be seen that water for flushing out the ashes is furnished from a tank 32 by means of pump 33 which introduces it into the combustion chamber through line 34, as.v will be described later. FIGS. 5 and 6 illustrate the use of a drag chain for this purpose as an alternati-ve to using ilush water. Finally, the primary combustion chamber has a stack 35, controlled by damper 36, designed to carry olf that portion of the cooling air circulating around the vprimary combustion chamber which is not required for combustion air.

The secondary combustion chamber 12, which is designed to burn the volatile material, has associated with it a forced draft fan- 38 which is designed to furnish combustion air through duct 3-9 to preheating passages in the combustion chambers.

Controls are provided to control the operation of the two combustion chambers and 12. Among these controls is a temperature controller 42 which auto-mat- `ically monitors temperatures within the primary combustion chamber such as at locations 43 and within the secondary combustion chamber such as at locations 44. T-hese temperature monitoring points are connected with the temperature controller 42 through proper circuitry indicated in the diagram as lines 45 and 46. The temperature controller is also designed to control the operation of the forced draft fan 38 through circuitry 47. In addition to the temperature controller there is a draft controller 50 which automatically and continuously monitors the pressure `of the air in the primary combustion chamber 10 such as at point 51. This is accomplished through suitable circuitry such as line 52.

It is necessary that after their complete combustion, the hot gases from the secondary combustion chamber be quenched or cooled by a suitable device and passed through a fly ash or dust separator before discharging into the atmosphere. In t-he apparatus of this invention there is provided, for this purpose, a chamber 56 which is joined directly to the discharge end of the secondary combustion chamber through a conduit 57. The chamber is formed of an upper inverted conical section 58 and aloiwer cylindrical section 5-9. The upper inverted conical section 58 is equipped with a number of water atomizing sprays which are shown in FIG. 1 as Water inlets 60 leading into this section. The water for cooling the gases at this point in the process is provided by a Water supply tank 61 which in turn is maintained at a desired level by means of pump 62. 'Ihe water is supplied to inlet lines 60 through pipe 64 which is controlled by valve 65. Connected to the bottom portion of the cylindrical section 59 of the cooler is a gas duct 70 which leads into a multiplicity of cyclone collectors 71. These collectors are provided with a suitable dust gate or fly ash gate 72 and means for conducting fly ash into fly ash hopper 73 as will be more fully explained in connection with FIGS. 8 and 9. 'Ilhe cyclone collectors are equipped with suitable gas drawolf ducts 74 which in turn lead into an induced draft fan 84. Additional water can be supplied to the cyclone dust collectors through conduit 76 for improved and more complete Wet dust collection. A Water spray controller 78 is provided to regulate Water ow to the cooler from the supply tank 61.

Associated with the cyclone collectors is an induced dra/ft fan 84 which is driven by a motor 85. The fan bas an outlet 86 which leads to a stack 87 in which there is 'a smoke indicator 88. On the outlet 86 of the fan there is an air damper 89, and the draft in the primaryA combustion chamber is monitored by the draft controller 50 t-hrough suitable circuitry 90.

An emergency draft stack 40, controlled by an emergency draft gate 41 (or by other suitable means such as a movable covering) is provided to draw in cold air between the quenching chamber 56 and the cyclone collectors to protect fan 84 should the Water atomizing spray means fail to function.

It is now possible to describe in more detail each of the components making up the incinerator of this in vention wih reference to FIGS. 2-8.

The primary combustion chamber One embodiment of the primary combustion chamber is illustrated in more detail in FIGS. 2-4, and reference should be had to these figures in the following description o-f this embodiment of the primary combustion chamber. FIG. 3 illustrates a cross-section orf the primary combustion chamber along lines 3 3 of FIG. 2. It will be seen that this combustion chamber is comprised of an outer cylindrical t-hin shell 96 and an inner cylindrical supporting steel shell 97. Between shells 96 and 97 there is delined a passageway 98 through which air, to be preheated for combustion, can be circulated. Alternatively, the outer thin shell 96 can be omitted if the combustion air is not to be preheated.

The combustion chamber is lined with refractory bricks 99. It will be` appreciated from this construction that these refractory bricks are `self-supporting thus eliminating the necessity for using expensive ceramic 1inings held in place by intricate expensive steel braces. The refractory bricks 99 are, moreover, continuously cooled by the preheat air circulating in passage 98, or by radiation and natural convection to the atmosphere if the preheat passages are not present. The cylindrical design of the combustion chamber and the use of a cooled metal shell results in being able to use a lo-w cost refractory brick lining which requires no expensive retaining structures. A further result is the elimination of thermal insulation Whether external or internal. All of these factors in turn make possible an economical construction since ordinary, low-cost, standard shaped refractories can be used, and added economy in operation `is obtained inasmuch as relatively high combustion temperatures may be used without damaging the refractories which are cooled through the supporting shell 97.

In order to insure proper circulation of the preheating air Within pass-age 98 of the primary combustion chamber there are located in this passage upper baffles 100 and lower baffles 101. It will be apparent in FIG. 2 from the dotted line location of these baffles that as preheat air enters through passage 112 from the secondary combustion chamber it is forced to first pass in a forwardly direction and then in an after direction in its passage through the preheat passage 98. Pre'heated combustion air is supplied to the primary combustion chamber at two points. `One of these is under the grates by means of ducts. From FIG. 3 it will be lseen that this preheated air for combustion enters the combustion chamber through ducts 105 and is directed around the baffles 106 to pass upward through the area 107 and be available for burning refuse on the grates 108. These grates 108, which may be of any suitable construction, are designed to cause the refuse to move along toward the ash discharge end as it burns. The grates are supported in a suitable manner such as by supports 109, land are moved hydraulically or mechanically by well known means not shown.

The second point at which preheat air is introduced into the primary combustion chamber is in the upper part of the combustion chamber 110, i.e., over the grating 108. As will be -seen in FIG. 2 this preheat air is drawn off from the upper part of passage 98 through duct 113 which is controlled by valve 114 and introduced into the upper portion of the primary combustion chamber at desired points as secondary or overre air. In addition overre air may be introduced along the length of the primary combustion chamber through nozzles 111 (FIG. 3)

The after end of the primary combustion chamber fromvwhich the ashes are taken is equipped with suitable observation openings 115 which are held in a frame, 116 (see FIG. 8). These openings permit access to the combustion chamber. K

It is desirable to remove any ashes from under the incinerator grates and this may be done by washing them4 out with water or using a mechanical conveyor system. Thus it was shown in connection with FIG. 1 that a water supply line 32 conducted Water into the forward end of the primary combustion chamber. As will be seen in FIG. 4 a water channel 118 is provided which is an extension Iof the inner lining support 97. This wash water not only serves to flush out and wet down the ashes, but it also serves to cool any large clinkers or other hot solid materials which may be taken out of the combustion chamber. Further to cool the ashes which are removed from the combustion chamber there are provided a series of nozzles 125 which introduce water from water supply 124 into the ash outlet conduit 20.

Inasmuch as it is desirable to be able to remove the ashes from the combustion chamber without distributing any of them in the atmosphere, means are provided for taking out ashes in gas-tight seal arrangement, This also makes it possible to take out the ashes from the combustion chamber at any time without stopping the combustion process or disturbing the proper draft. In order to do this an efcient form of ash removal system is provided. This will be seen clearly in FIG. 4 in cross-section. This ash removal system comprises a retractable horizontal plate or gate 128 movable in the horizontal plane such as by being rolled back and forth on rollers 129. It is equipped with remote control means (not shown) or with a handle 138 which is connected to the plate 128 through a shaft 131. The shaft operates in an airtight gate extension 132. Suitable ash guides 133 are provided for directing th-e ashes into a receptacle.

The ash receptacle or hopper 22 in turn is so designed and arranged that it may be brought into direct contact with a sealing iiange 136 which is part of the ash gate 21. This ash hopper is supported on a platform 137 (see FIG. 8) which can be moved vertically by a suitable hydraulic lift 138. When in its loading position the edges of hopper 22 form an air-tight and ash-tight seal with the sealing flange. 136. Under normal operating conditions the ash hopper 22 will be -in position, as in FIG. 4, to receive ashes and the gate 128 will be retracted into extension 132. When the ash hopper is filled, gate 128 will be m-oved to close 011 the iiow of ashes from the combustion chamber and the full ash hopper interchanged for an emtpy one by lowering platform 137 and breaking the seal. As soon as the emtpy hopper is in place, -gate 128 is opened, allowing ashes to ow from the combustion chamber into the unfilled hopper. The iilled hopper containing the ashes from the incinerator is transported vby suitable means to the ash disposal area without other handling or transfer of the ash. Thus, it is unnecessary to use costly ash convey-ors which cause interruptions from entanglement of metal pieces in the ash or from mechanical failure.

As an alternative to moving the ash hopper up and down to provide the necessary vertical exibility in making the seal, the duct below the gate, i.e., the ash gate 21 may be extended a sbellows to provide the gas-tight connection to the ash hopper 22.

A modification of `the primary combustion chamber is illustrated in FIGS. 5 and 6. This modification incorpor'a`tes the basic concept of an essentially horizontal cylindrical combustion chamber formed, as in the case of the primary combustion chamber of FIGS. l4, `of an outer shell 96 and inner supporting shell 97 having apreheat air passage 98 and being lined with a ceramic brick lining 99. FIG. 6 illustrates the use .of st iiening rings 102 surrounding the inner supporting shell 97 to maintain a circular section. cienty thick steel, then such rings are not required.

The combustion chamber of FIGS. 5 4and 6 differs from the combustion chamber of FIGS. 1 4 in that it provides gravity feed of the refuse thus eliminating the refuse gate 16 and provides distinct burning zones in which the burning is controlled. It also provides an alternative means for removing the ashes as well as an alternative way in which the preheated over-tire air may be introduced to create a desirable air iiow pattern in the combustion gases above the refuse and to cool the brick lining.

If the shell 97 is formed of suffi-l In the embodiment in FIG. 5 refuse is fed by gravity through an inlet conduit 166 which delivers the refuse to the highest section of the grating. Because of the radiant heat emitted by the burning material it is desirable to provide for the cooling of the lower portion of the inlet conduit 166. This is done by circulating a coolant such as air or water in the passage 167, a passage which serves also to form a support within the combustion chamber on which the brick lining 99 is mounted.

The grates in the combustion chamber of FIG. 5 are lowered by discrete steps and it will be seen that it is formed in this embodiment of four sections 170, 171, 172 and 173. Grates suitable for the lburning and transportation of burning refuse are well-known in the art and may be of the pusher, rocking or chain type, for example. The area under each of the grating sections -is divided off by suitable partitions 175, 176, and 177 to define under these grates zones 178, 179, 180 and 181. By the use of such zones it is possible to control both the temperature and the pressure under each of the sections of the grates to optimize combustion conditions in each of the areas. Viewing ports 183 are provided for monitoring the conditions prevailing within the combustion chamber.

As noted above, the primary combustion chamber of FIG. 5 illustrates an alternative means for continuously moving ashes which fall through the grates to the ash collection zone. In place of ushing the ashes with water, means are provided in the combustion chamber of FIG. 5 for conveying the ashes in a dry condition. This is conveniently done by moving them Ialong with a drag chain conveyor 185 which is driven by suitable sprockets 186 located -at both ends 'of the combustion chamber. These drag chains 185 are preferably located in troughlike extensions 188 (see FIG. 6) which are joined to the outer shell 96 making up the combustion chamber. It will be seen in FIG. 6 that in place of the ducting system shown in FIG. 3 this arrangement provides for direct communication between the preheat air passage 96 and the area 190 which is between the trough-like extensions 188 and the interior 110 of the combustion chamber. The grates 173 (shown for convenience as a dotted line in FIG. 6) are seen to be supported on a steel support beam 192 which extends across the bottom of the combustion chamber and is joined to the inner supporting shell 97. It will be appreciated that support beams such .as 192 are spaced periodically and that they thereby dene passages through which the preheat combustion air is brought from the passage 98 up into the com-bustion chamber through the bottom of the refuse which is represented in FIG. 6 by the numeral 194. The flow of this air is controlled by dampers 193 located between passage 98 and area 190.

In the operation of the primary combustion chamber of FIGS. 1 4 or FIGS. 5 and 6, the use of preheated air for combustion permits burning wetter or lower grade municipal refuse.

vThe primary combustion chamber of FIG. 5, because of the arrangement provided for introducing the refuse, does not have an over-fire preheat air duct corresponding to duct 113 of the combustion chamber of FIG. 1. It is therefore necessary to provide other means for introducing Aover1ire air and this is accomplished, as s-hown in FIG. 6, through -a series of nozzles 196 which lead the over-lire air from passage 98 into the upper portion of the combustion chamber 110. (It will be recalled that similar nozzles 111 may be used in the combustion chamber of FIGS. 1 and 2.) By imparting to the over-hre `air the tangential direction illustrated in FIG. 6 it is possible to give it a circular ow pattern as illustrated by the arrows and thus to provide a degree of turbulence in this part of the combustion zone. It will be appreciated that air flow patterns of this character also provide for additional cooling of the refractory brick surface, particularly in those areas where radiant heat is intense.

Secondary combustion chamber The construction of t-he secondary combustion charnlber which is designed to completely burn all of the volatile materials and light-weight solid particles suspended in them is similar to that of the primary combustion chamber, except that it does not have a grate. The secondary combustion chamber is s-hown in cross-section in FIGS. 4 and 7. Turning now to FIG. 4, it will be seen that the secondary combustion chamber 12 is also a horizontal cylindrical configuration and is made up of a thin cylindrical metal outer shell 140 and a heavier supporting cylindrical metal shell 141 which deiine between them a passage 142. In a manner similar to that .of the primary combusti-on chamber, the secondary combustion chamber is lined with the same type of refractory Ibrick lining 143, Iand the supporting shell 141 may have stiffening rings 149. As in the case of the primary combustion charnlber, it is unnecessary to supply any thermal insulation and the bricks are so designed for a cir-cular arch that they are retained in place Without the use of an intricate support system. It is also possible to operate this combustion cham-ber at relatively higher temperatures lbecause of the cooling of the refractories through the cylindrical metal shell 141. As in the case of the primary combustion chamber it is possible to eliminate the air preheat passage and achieve cooling by radiation and natural convection to the atmosphere. As will be apparent from FIG. 8 the preheat air is forced by means of a forced draft fan 38 through duct 39 into the passage 142 of the secondary combustion chamber. It is preferably introduced tangentially so that the air swirls around in the passage 142 and is driven to the end of the secondary combustion chamber through duct 112 (FIGS. 3 and 4) into the preheat air passage 98 of the primary combustion chamber. Alternatively the passage 142 of the secondary combustion chamber may 'be equipped with Iballles similar to those in passage 98 of the primary combustion chamber (FIGS. 2 and 3).

Secondary combustion air is added to the secondary combustion chamber from the preheated air passage 142 through suitable nozzles 148 shown in FIG. 7. This secondary air is preferably introduced near that end .of the secondary combustion chamber which is in communication with the primary combustion chamber. This air serves to control and to promote mixing and to give a homogeneous reaction mixture. If it is introduced tangentially as illustrated in FIG. 7 it is also available las a coolant for the faces of the brick lining exposed to the heat of the combustion cham-ber.

' The ceramic brick lining of the secondary combustion chamber is extended as shown by lining 144 (FIG. 4) so that the entire duct 13 between the two combustion chambers is lined and protected .against t-he heat generated in the combustion. The primary combustion chamber area 110 thus leads directly into the secondary combustion chamber 145. This secondary combustion chamber is provided with a gate 146 for inspecting and repairing any of the components within the secondary com-bustion chamber. Gate 146 also permits the introduction into the secondary combustion chamber of animal bodies for cremation, a process which requires a longer burning period than would be available if they were put into the primary combustion chamber.

Although it is preferred to provide separate primary Iand secondary combustion chambers as illustrated and described, it is possible to make the secondary combusti-on chamber integral with the primary combustion chamber either by extending the length of the primary combustion chamber or by increasing its diameter or other suitable modification.

Cooling system Combustion of the volatiles in secondary combustion chamber 12 takes place at labout 14002000 F. This means that the gases which have been burned will have to be cooled as well as have the light-weight solid matter in them removed. The removal of this solid matter and partial cooling is accomplished in the chamber 56. The cylindrical portion 59 of the chamber 56 is equipped with an access door 75 (FIG. 8) which provides access to the chamber 59 to remove settled solids. Alternatively, the bottom of 59 can be of a conical configuration which connects with duct 70.

It Will be seen from FIIG. 9 that these gases are directed from the secondary combustion chamber through duct r57 to the cooler. The duct is lined with suitable refactory lining 147 to that point where the gases become cool enough so that a metal surface may tolerate the temperatures. In order to cool the gases and to effect a collection of the solid materials, the gases leaving the secondary combustion chamber are sprayed with water supplied through line 60 to spray nozzles 150. Cooling is carried out to the extent that the gas entering duct 70 is about 600 F. It will be appreciated that under these circumstances the Water is still in vapor form `and no appreciable quantity of liquid Water collects in the bottom of the scrubbing tower 59. Duct 70 lleads into a number of cyclone collectors (FIG. 10) such as the one shown in FIG. 9. The gases enter tangentially into the upper section 152, are then directed down in a swirling motion in-to the conical section 153 and pass through the outlet duct 154 into a header 155 and thence into a collecting duct 156. From here the gases are led (as will be shown in FIG. l0) into a common duct 157 and nally cinto the inlet 158 of the induced draft fan 84 and are subsequently swept out of the stack 87.

The solid material which is collected in the cyclone collector 71 is taken out through the gate 72. The gate may consist of any suitable device designed to periodically permit the solids to fall into the outlet extension 162 which is connected to the ash hopper 73 through a flexible coupling 163. An arrangement such as shown in FIG. 4 may also be used to remove the solid materials from the cyclone separator 71, that is, the hopper may be joined through a sealing flange such as 1'36 shown in FIG. 4 As explained in connection with that figure, this arrangement permits solid materials to be removed without introducing any of them into the surrounding atmosphere or without admitting ambient air.

Although the figures described above illustrate one primary combustion chamber, one secondary combustion chamber, a single cooler and four cyclone collectors, it will be apparent to those skilled in the art that these components may be varied both with respect t-o the number used and to their location within a -given area. For example, it is possible to use one secondary combustion cham-ber to burn the volatiles given oi from two or more primary combustion chambers or to combine the primary and secondary combustion chambers into one. Likewise it is possible to incorporate fewer or more cyclone dust collectors depending upon their design and the amount of solid materials which must be removed from the gas stream. It is also Within the scope of this invention to use other means for reducing temperatures of the combustion gases other than the water-spray cooler, such as a heat exch-anger or a waste heat boiler. However, the components indicated appear to be preferable in the overall incinerator assembly.

It is also, of course, within the scope of this invention to use other means and for removing the ashes below the grates, for removing the solids from the ash gate of the combustion chamber =or rfor taking out the solid materials from the dust cyclone collectors. However, it is believed that the means provided as illustrated in the gures offer an efficient method and apparatus 4for removal of solid materials without introducing any harm-ful contaminants into the surrounding atmosphere. Moreover, they oi'rer the possibility of continuous processing of the refuse without the necessity of shutting down a combustion chamber to remove solid matter which has collected.

Operation of incinerator Returning now to FIG. 1, the operation of the incinerator in this invention may be very .briey described. Refuse to be burned is brought up by the crane, or other suitable loading device and deposited into the charging hopper. If a charging gate is used it is opened and the refuse is permitted to drop into the primary combustion chamber, falling on the forward end of the moving gate. Alternatively, if gravity 'feed is used as in FIG. 5, the refuse will automatically build up on the grate under the force of gravity. Ignition is achieved initially by merely dropping in seme burning material. As the grates move the refuse fonward, combustion air which may be preheated 'is supplied both under the gr-ates and over the tire, as explained in conjunction with FIGS. 2 `and 3. The solid material as it burns is moved along to the after end of the combustion chamber by means of the grates, and by the time it has reached the after end of the primary combustion chamber all of the combustible part of the solid material has been completely burned and is deposited into the ash hopper 22. Water flowing in through line 34 has at the same time Washed dow-n any ashes which have fallen into the Wash Water channel 118 (see FIG. 4) or the drag chains have carried the ashes along as shown in FIGS. 5 and 6. After the motion of the after-end Vgrates has been stopped, the ash gate m-ay be closed by an operator who performs this operation either manually or automatically by causing the collector plate 128i (FIG. 4) to slide from the recess 132 into closed position, permitting the interchanging of empty ash collectors 22 for full ones without loss of draft or creation o'f smoke. After the ash hoppers have been interchanged, the after-end grates are again prut into motion and the gate 128 is withdrawn -into recess 132 permitting ashes to drop directly into the hopper. Of course in the meantime the material has been cooled and wetted down by means orf water sprayed onto it through nozzle 125.

In a typical opera-tion of this incinerator, temperatures within the primary combustion chamber may reach about 2000 F., while the refractory brick Vlinings reach a temperature slightly lower than this. The preheated combustion air delivered below the grates will typically lbe at about G-400 F. while that introduced above the grating and over the fire will be at about 10U-300 F.

The gaseous or volatile materials which are present in the primary c-ombustion chamber, along with any solid materials which are too light to be deposited upon the grate and removed through the ash gate, are taken through conduit 13 into the secondary combustion chamber where they .are further burned before being released into the atmosphere. The cremation of any animal bodies is also carried out in this chamber. Combustion temperatures within this secondary combustion chamber will usually reach about 1400-2000 F. Since these volatiles contain suspended solid particles it is necessary to remove these solid particles .and this in turn dictates a certain amount of cooling before separation so that it may be achieved in standard steel or iron equipment at a reasonably tolerable temperature. Cooling is accomplished by contact with water spray in the upper conical section of the spray chamber. The extent of cooling lies within that range which maintains essentially all of the water in the vapor state and yet which is low enough to permit its being handled in the cooler duct, cyclone dust collectors, induced d-raft fan and stack. The solid particulate material separated out in the dust collector is periodically removed into the ily ash hopper and, along With the ashes which have been deposited into the ash hopper associated with the primary combustion chamber, are taken away for further disposition.

Simultaneously with the operations described, the forced draft fan 38 has been supplying combustion air by means of line 39 into the passageway for the preheat air of the secondary combustion chamber and thence into the preheating passageway of the primary combustion chamber to be delivered as preheated combustion air under the grate and over the lire of the primary combustion chamber and into the secondary combustion chamber.

It will be seen from the above description that the incinerator of this invention provides a complete and economical way of handling refuse. Moreover, it eliminates the possibility of introducing any contaminant material into the atmosphere. By the construction of the primary and secondary combustion chambers, that is, in the use of preheat air to cool the refractory material and supporting shells and by designing the combustion chambers as cylinders to permit the use of low-cost refractory brick linings without any expensive supporting systems, it is possible to construct an incinerator which is economical to build and to operate. Maintenance costs on such an incinerator are small inasmuch as the combustion conditions are such as to maintain the refractory bricks at temperatures below that at which they will slag or ux; and even if some are destroyed they are cheaply and easily replaced. Moreover, the incinerator of this invention offers a great deal of flexibility in arrangement and in the amount of refuse which it can handle. Thus by using various combinations and sizes of components of secondary and primary combustion chambers 4along with associated spray chambers and dust collectors it is possible to design an incinerator which can handle anywhere from 10 to 1000 tons per day It will thus be seen that the objects set forth above among those made apparent from the preceding description are eiciently attained, and since certain changes may be made in the above constructions without departing from the scope of the invention it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. An incinerator suitable for burning refuse, comprising in combination (a) a substantially cylindrically-shaped, substantially horizontal, stationary primary combustion chamber having a lining of a self-supporting refractory over substantially all of that part of the interior exposed to hot combustion products, said combustion chamber being formed of a metal shell adapted to be cooled by contact with fluid therearound;

(b) refuse charging means associated with one end of said primary combustion chamber;

(c) grate means Within said primary combustion charnber adapted to advance burning refuse retained thereon;

(d) a substantially cylindrically-shaped, substantially horizontal, stationary secondary combustion chamber having a lining of a self-supporting refractory and being formed of a metal shell adapted to be cooled by contact with a fluid therearound;

(e) refractory-lined conduit means communicating between said primary combustion chamber and one end `of said secondary combustion chamber;

(f) means for providing over-fire combustion air to said primary and secondary combustion chambers .and combustion air under said grate in said primary combustion chamber;

(g) ash removal means located at the outlet end of said primary combustion chamber and associated with said grate means to remove the ashes resulting from said burning of said solid refuse; and

(h) flue gas Idischarge means associated with the other end of said secondary combustion chamber.

2. An incinerator in accordance with claim 1 further l characterized by having air passage means substantially I 3. An incinerator in accordance with claim 2 further characterized by having duct means communicating between said air passage means and the interior of said primary combustion chamber above and below said grate means and duct means communicating between said air passage means and the interior of said secondary cornbustion thereby to provide at least a portion of said combustion air in a preheated condition.

4. An incinerator in accordance with claim 1 further characterized as including means under said grate means adapted to remove ashes therefrom and convey them to said ash removal means. 5. An incinerator in accordance with claim 1 further characterized by having the undergrate volume of said primary combustion chamber compartmentized into discrete zones thereby to control combustion conditions above each of said zones.

6. An incinerator` in accordance with claim 1 wherein said ash removal means comprises means to cool said ashes and gate means adapted to permit removal of said ashes in a manner to avoid air infiltration during said removal and to develop a gas-tight seal with an externally joined ash hopper.

7. An incinerator in accordance with claim 1 wherein said iiue gas discharge means comprises cooling means adapted to cool combustion gases removed therefrom, means for separating residual suspended solid matter from the cooled gases, and means for transferring said solid matter to an external receiving means.

8. An incinerator in accordance with claim 1 wherein said discharge means comprises a quenching chamber incorporating said cooling means and wherein said means for separating residual solids comprises a'plurality of cyclone scrubbers.

9. Incinerator in accordance with claim 8 further characterized as having an emergency draft gate associated with said quenching chamber and said cyclone separators and adapted to introduce cooling air into said discharge means if said cooling means malfunctions.

10. An incinerator suitable for burning refuse, comprising in combination (a) `a substantially cylindrically-shaped, substantially horizontal stationary combustion chamber means having a lining of a self-supporting refractory over substantially all of that part of the interio-r exposed to hot combustion products and formed of a metal shell adapted to be cooled by contact with fluid therearound, said combustion chamber means being divided into (1) a rst cylindrical section adapted to burn solid refuse therein; and

(2) a second cylindrical section, joined at its inlet end to the outlet end of said first section by refractory-lined conduit means, adapted to burn volatiles therein;

(b) refuse charging means associated with the inlet end of said first section of said combustion chamber means;

(c) grate means within said rst section of said combustion chamber means and adapted to support said solid refuse and to advance it during burning;

(d) means for providing over-fire combustion air to said iirst and second sections of said combustion chamber means and combustion air under said grate in said first section;

(e) ash removal means located at said outlet end of said rst section and associated with said grate means to remove the ashes resulting from said burning of said solid refuse in said irst section; and

(f) iiue gas discharge means associated with the outlet end of said second section of said combustion chamber means.

References Cited by the Examiner UNITED STATES PATENTS 377,600 2/1888 Brown 11.0-170 417,879 12/1889 Myers 126-245 X 559,519 5/1896 Eaves 110-56 640,228 1/1900 Rumpf 110-171 X 676,930 6/1901, Wees et al 110-165 981,254 1/1911 Fortune et al 110-8 1,555,513 9/1925 Nibecker 110-14 1,600,711 9/11926 Bullock 110-56 1,813,156 7/1931 Gilchrist 110-7 1,843,274 2/1932 Foresman 110-171 1,979,189 10/1934 Bowers 55-238 X 1,988,473 1/1935 Bennett 110-165 2,375,436 5/1945 Noack 110-165 2,696,275 12/1954 Pring 55-238 2,735,265 2/1956 Eastman 60-3905 2,940,733 6/ 1960 Umbricht 55-257 X FOREIGN PATENTS 764,086 2/19'34 France. 1,092,6119 11/ 1960 Germany.

28,707 1903 Great Britain. 586,872 4/ 1947 Great Britain.

FREDERICK L. MATTESON, J R., Primary Examiner. H. B. RAMEY, Assistant Examiner.

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Classifications
U.S. Classification110/214, 261/118, 55/429, 110/215, 261/DIG.900, 110/216
International ClassificationF23G5/16, F23G5/00
Cooperative ClassificationY10S261/09, F23G5/165, F23G5/006
European ClassificationF23G5/16B, F23G5/00P