DE2444641A1 - OVEN WITH SINGLE OR MULTIPLE STOVES AND PROCEDURES FOR TREATING MATERIALS IN SUCH OVENS - Google Patents

Description

25 849 t / wa

NICHOLS ENGINEERING & RESEARCH CORPORATION, BELLE MEAD, N.J./USA

Oven with one or more hearths and methods of treating materials in such ovens

The invention relates to an oven with one or more herds and in particular devices and methods for Distributing solid-like material to be treated over a furnace hearth. The inventive concept is especially in addition to other possible use cases

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suitable for ovens with a variety of vertically spaced mutually arranged stoves, for example for the treatment of waste or sewage sludge, roasting ores and to be used in other processes.

As is well known, the problem of avoiding air pollution is has become a critical moment today. The invention is therefore particularly directed to a substantial reduction of particulate matter, hydrocarbons, Carbonyls, visible smoke and other contaminants in furnace exhaust. So far, these gases have contained particles, undesirable Gases and stable organic aerosols (including tar vapor or mist), these impurities being in the are a major consequence of incomplete combustion. Since they can have harmful effects on health, they make a significant contribution to air pollution. The problem got so serious that National Air Pollution Control Administration and the Environmental Protection Agency are constantly tightening their minimum requirements to have. Despite this Ömstandes certain factors have not been taken into account so far, which on the problem of incomplete Incineration make a significant contribution.

One aim of the invention is therefore to improve a furnace of the type in question which has been used up to now Furnaces and particularly to provide improved apparatus and methods for incinerating the combustible products.

The invention is based on the knowledge that in particular incineration of sewage sludge and the like in ovens with a large number of stoves is uneven Distribution of the material to be treated over the first

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or upper focal point leads to the fact that the following foci or treatment zones are also uneven Distribution continues. The uneven distribution of the material over the hearth or the treatment zone is a problem Number of undesirable effects, such as wasted stove surface and thus reduced oven capacity, as well as the production of a non-uniform product. This can be the case with some systems a smoldering or smoldering in only one side of the hearth

set thin material deposition zones and the like, which can lead to air pollution problems of some sort which are very difficult and or costly to dismantle.

A uniform and even distribution in the context of the invention means that over the entire surface of the Treatment zone there is a substantially uniform flow of material. The material is essentially the same Depth in all quadrants or sectors of the hearth at any diameter, possibly with the exception the extreme inner or outer diameters associated with the feed inlets, and where none the less at least some flow of material around the whole Circumference is provided to avoid dead zones and / or flow rate non-uniformity over part of the cooker is reduced to a minimum relative to the other hearth zones.

In order to move solid-like material over the hearth of a multi-hearth oven, various devices, such as for example stirring teeth and discs are used. Also were Chains have already been provided that extend between the agitator arms on lower inflow cookers, with the

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material that is directed radially inwards easily accumulates. These Chains were used to reduce the drive torque for the central shaft in furnaces for the treatment of copper and Zinc. Such measures are described in U.S. Patents 3,153,633, 3,379,622, 3,419,254, 1,251,692, 1,879,680, 2,067,823, 2,117,487, 2,138,120 and 2,696,377. However, the devices disclosed therein do not make it possible for the material to be treated to be uniformly distributed over the flock is distributed.

In contrast, to achieve the effects mentioned above, it was found that separate control devices must be provided for the forces that generate the radial and circumferential plus components of the material. The Set the angle of the stirring teeth so that both a suitable radial and circumferential material flow over the stove is very difficult, if not impossible. This in particular due to the fact that the material to be treated changes continuously over time, especially with regard to its physical properties changes. As a result, the angle has hitherto been set in such a way that there was an excessive radial flow, which ensured should be that the material does not remain on the stove in the presence of any flow conditions, i.e. not inwards or outwards to the drop bores and from there to the following hearth below. This so far Practiced interpretation leads to the fact that during normal operation one excessive radial and one only there is slight extensive movement.

According to the invention, on the other hand, a device for controlling the radial flow vector via the hearth and a separate or

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independent means for controlling the circumferential flux vector intended for the material. In this way, the material from a highly populated sector can be used circular cooker to another less stocked sector of the cooker by means of an independent circumferential Movement element are distributed. In this way, a number of beneficial effects are achieved, as can be seen from the the following explanations.

According to the invention, therefore, a new and improved device for evenly and uniformly distributing solid-like material above the hearth of an oven with a single hearth or the top hearth of an oven with a multitude of cookers. In the case of a multi-hearth oven, there is one A plurality of vertically spaced apart cookers and a rotatable central shaft are provided which extend extends upward through the center of the furnace and on which a plurality of spaced apart agitator arms are attached. The agitator arms protrude radially outwards over every stove. Furthermore, drop bores are either in the area of the central shaft or in the area of the hearth Furnace wall provided so that the material after completion of its movement over one stove down to the next one the stove below. To create the radial flow component for that to be treated on the upper hearth Material a device is provided and further a further device is provided on the stove that regardless of the former, to create the radial flow component the circumferential material flow component is generated so that when the central shaft rotates the material over the entire stove area is distributed while avoiding dead zones.

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According to a further development of the invention, the The topmost hearth can be an inflow or, in another embodiment of the invention, an outflow hearth.

At the facility to create the radial material flow component it can be stirring teeth that protrude from the stirring arms to almost the bottom of the stove and down are inclined with respect to the longitudinal axis of the agitator arm in question, so that the material to be treated radially over the hearth is acted upon in the direction of the assigned downhole. According to a further development of the invention, it is the device for creating the extensive material flow component chain-shaped elements which are arranged between the agitator arms associated with the upper hearth. The extensive one Material flow components can also be generated by elongated rod-shaped elements carried by stirring teeth which extend substantially parallel to the longitudinal axis of the agitator arms. According to another further training According to the invention, alternating stirring arms are provided which carry stirring teeth which are inclined to the longitudinal axis of the stirring arms are and act on the material radially via the stove and other stirring arms are provided that carry stirring teeth, which extend essentially parallel to the longitudinal axis of the agitator arms in question and the material in the circumferential direction apply over the stove.

Furthermore, according to the invention, there is a method of treatment of solid-like material in an oven with a single hearth or in an oven with a plurality of vertical spaced stoves, a revolving central one, running through the center of the oven and through each one Hearth through upwardly extending shaft, in the area of the

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central shaft or outside in the area of the furnace wall arranged drop bores in the hearths and a large number of provided on the central shaft at a distance from each other attached agitator arms, which extend radially outward over each Extending stove and which is characterized in that one enters the material at the top of the oven and it over at least the uppermost hearth in a critical zone with a radial flow component and at the same time above it Hearth with an independent circumferential flow component compulsorily moved so that the material is distributed over the entire area without the formation of dead zones.

In some embodiments of the invention, the term top hearth is used in a critical zone because in some systems the aforementioned material distribution device on the topmost hearth in the oven may not be necessary must be applied. In other words, the first few stoves in the oven can be a non-critical zone It is of secondary importance whether the material is distributed over the entire hearth zone without the formation of dead zones will or not because of the supply of heat or a certain amount of reaction with the gas / kg of material for the to be carried out Process * or uneconomical. However, in order to obtain the advantages which can be achieved by the invention it is necessary that once the material has reached the critical zone, the distribution facility is provided to to distribute the material to be treated over the entire stove area without dead zones.

In many plants it has been found that if there is a uniform distribution of material in one of the upper hearths the same even distribution to the following herds

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continues through the furnace without the device repeated in the last-named herds for uniform circumferential Distributing the material must be provided. In other systems, however, it is advisable to use the above-mentioned distribution device to be arranged repeatedly also with the lower hardnesses. For ovens, for example, where the inner drop hole and the central shaft are not exactly concentric with each other, the uniform distribution once achieved may possibly due to a non-uniform material structure, e.g. in the form of slag, destroyed on the circumference of the downhole as the river flows primarily over the wider area of the downhole and to a lesser extent over the area of the Drop hole takes place that is closest to the center of the shaft. When burning lime, for example, or when roasting of sulphide ores, the lighter river zone is "roasted" before the heavier river zones (reaction has taken place), so that the The area of the lower herd, which subsequently receives the material from the lighter river zones, is wasted, as it is already here finished material is subjected to the treatment again. Also in cases where significant heat reactions take place, which produce massive temperature differences in the case of considerable gas proportions, an early completion of the reaction in the Lighter flow zones lead to overheating of the material in these zones once the reaction has taken place.

In cases where it is about the activation and reactivation of carbon goes, the material in the low-flow zones will be at least to a low-exploitation state with a high ash content reacted and possibly completely incinerated while activating for the remaining material in the High river zones are still in the state of completion.

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When incinerating sewage sludge or other types of incineration or reactions that involve certain components of the gas flow, such as oxygen from the air the incineration of sewage sludge as much as possible, it is important to take into account that in many cases that Gas flows upwards in a laminar manner along the furnace, so that the gas flow in the first quadrant of the floor hearth in the first quadrant of the herd following in the upward direction. The heavy flow zone, however, turns from a hearth to the next. As a result, a quarter of the gas flow connects the heavy flow from one hearth to the next and frees it completely from oxygen or other reaction gases, while the gas is in the light flow quadrant still contains oxygen or other reactive gases not available in the severe reaction zone. Due to the local differences in the air required for combustion, dark smoke can arise, for example, although the total gas flow can easily contain more than the stoichiometric oxygen requirement.

On the basis of the foregoing, the invention has been described in more detail in its fundamental characteristics, from which it follows that Further features of the invention contained in the following description are also essential to the invention. In this Context, it should be noted that the disclosure of the invention can be used as a basis for interpretation by others Arrangements and procedures can be used. Such equivalent constructions and methods are therefore essential and to include the scope of the invention.

Embodiments of the invention are explained in more detail below with reference to the drawing. Show it:

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Fig. 1 is an axially sectional view of a furnace with a plurality of cookers,

FIG. 2 is a cross-sectional view of an upper inflow cooker showing the distribution of material in FIG known procedure,

3 is a cross-sectional view of an upper inflow cooker showing the distribution of material in use the inventive concept,

Figure 4 is a cross-sectional view of an upper outflow cooker with representation of the material distribution according to the conventional procedure,

Fig. 5 is a cross-sectional view of an upper vent showing the distribution of material in use the inventive concept,

6 is a sectional view of the upper part of a furnace provided with the invention;

7 shows a section along the section line 7-7 according to FIG. 6,

8 is an enlarged view of an intermediate stirring arm arranged chain according to the invention,

Figure 9 is a perspective view of an upper range of an oven showing the operative position the chain,

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Fig. 10 is a perspective view of an upper range similar to Fig. 9 with a different manner of attachment the chain,

Figure 11 is a perspective view of an upper range similar to FIG. 9 with a further alternative way of attaching the chain,

Figure 12 is a perspective view of an upper range similar to FIG. 9, but showing a different embodiment of the invention, in the cable with Blades are arranged between the agitator arms,

Figure 13 is a perspective view of an upper range similar to FIG. 9, but showing a further embodiment of the invention in which between Stirring rods are arranged, and

Figure 14 is a perspective view of an upper range similar to FIG. 9, but showing yet another embodiment of the invention in which the teeth on alternating agitator arms to create a circumferential or radial material flow are aligned accordingly.

In the drawing, and in particular in FIG. 1, the upper part of an oven 10 is shown with a plurality of cookers, the furnace being generally cylindrical in shape. The furnace consists of a tubular outer steel jacket 12, which, as indicated at 14, is lined with firebrick or a similar heat-resistant material. Although in some systems burner nozzles only in one or two lower ones

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Cookers are provided, in the present embodiment, each cooker is equipped with a plurality of burner nozzles 16, which extend both axially and tangentially into the hearth. The ones with the omission of various individually controlled, not shown burner assemblies connected burner nozzles are distributed over the furnace 10 and serve to generate and / or maintain appropriate temperature and atmospheric conditions in the various Zones of the oven to provide the specific treatment desired. There are also special work doors and windows 18 is provided to monitor the operation of the oven at each hearth level.

The interior of the oven 10 is divided into a plurality of vertically oriented ovens by means of hearth floors 20 and 22, only the top four flocks are shown. Each hearth floor is made of a refractory material and is preferably slightly curved, so that the floor is given a self-supporting property in the oven. Near the outer coat 12 of the furnace, outer, circumferentially extending drop bores 24 are provided, while near the center of the Oven in alternating hearth floors 22 central drop bores are formed. Although in Fig. 1 the top or first Hearth is shown as an outflow hearth, it goes without saying that the inventive concept in the same way an oven having a first single-flow hearth or a lower hearth of a multiple-hearth oven can be.

Referring to Fig. 1, a rotatable vertical central shaft 28 extends axially through the furnace 10. The shaft 28 is as at 30 indicated by an upper bearing and a not shown

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lower camp held. It is rotated by suitable drive means of known type, not shown. One A plurality of spaced apart agitator arms 32 are attached to the central shaft 28 as indicated at 34, the paddle arms in each hearth extending outwardly above the hearth floor. There are stirring teeth on the stirring arms integrally formed, which extend down to near the hearth base. The mixer taps are inclined to the longitudinal axis of their associated mixer arms, so that when the agitator arms 32 move as a result of the rotation of the central shaft 28, the agitator teeth 36 continuously through scrape the material to be treated on the relevant hearth base and gradually move it to the drop bores 24 and 26 in force the soil.

The material to be treated is fed into the furnace at its upper end by means of a belt conveyor 38 and a filling inlet 40 entered. As shown in FIG. 1, when the top hearth is an effluent hearth, the fill inlet 40 is near the furnace center. However, if the top stove is a single-flow stove, the filling inlet will be moved towards the perimeter of the stove. That Material generally moves in a serpentine manner through the furnace down and is drained from the bottom of the oven. At the top of the furnace is a gas outlet port 42 provided through which gases and other combustion products formed during operation in the furnace are carried out can.

Fig. 2 shows the 'flow of the material to be treated according to the prior art, the first hearth being a single-flow hearth 22. The material generally designated 44 enters the hearth from above through a feed inlet 46 and, according to arrow 48, is partially around the hearth

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as a result of the stirring teeth moving in the direction of the arrow 49 so that the material finally falls through the central drop hole 26. The stirring teeth are to the longitudinal axis of the relevant agitator arm inclined, so that the material movement a relatively large radially inward flow component 50 and a relatively small circumferential flow component Has flux component 52, which leaves a substantial part or section of the hearth uncovered or very thin with material remains coated, as indicated by reference number 54.

In contrast to FIG. 2, FIG. 3 shows the material flow according to the invention, the first hearth being a single-flow hearth 22. The material generally designated 56 enters the Hearth from above through the feed inlet 46 and is according to the arrow 58 moves completely over the hearth and falls through the central drop hole 26 substantially along the entire length thereof Circumference. According to the invention, a measure is therefore taken to reduce the radial flow sector or the material component 60

and further separate and independent means are provided around the circumferential flow sector or material component 62 to control. In this way, the two river sections can be selected individually so that the material is brought to an even distribution over the entire stove without creating dead zones, this by means of the independent selection of the two components takes place. In addition, the material dwell time in the oven can be set between Targeted influence on entry and exit according to the material and the treatment concerned.

In Fig. 4 an outflow hearth 20 is shown, wherein the flow of material is indicated according to known techniques. That

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Material 64 enters the hearth from above through an inlet 66 and, as indicated by arrow 68, is distributed by means of of the stirring teeth rotating in the direction of arrow 70 only partially over the hearth before it passes through the circumference arranged drop bores 24 falls. It should be noted that the stirring teeth to the longitudinal axis of the relevant Agitator arm are inclined, so that a relatively large radially outwardly directed material flow component or a vector 72 and a relatively small circumferential flow component or vector 74 is created, and thus a substantial part 76 of the hearth remains uncovered or only thinly covered with the material to be treated.

In contrast to the known flow configuration according to Fig. Fig. 5 shows the flow formation in an outflow center 20 with material treatment according to the invention. That in general with Material designated 78 enters the hearth from above through the feed inlet 66 and moves according to the arrow 80 completely around the hearth and falls substantially along its entire circumference through the circumferential bores 24. As follows will be explained in more detail, means are provided to control the radial flow vector or the material component 82 and separate or independent means are also provided to apply the circumferential flow vector or material component 84 steer. It follows that the peripheral component 84 according to the invention is significantly larger than the circumferential component 74 in the prior art, so that a uniform flow distribution is present without dead zones over the entire hearth. This fact is ensured by having the control of the circumferential component 84 is independent of the control of the radial component. In addition, the material residence time on the stove can be controlled in a targeted manner according to the material and the process in use.

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The known technique shown in FIGS. 2 and 4, in contrast to that according to the invention shown in FIGS. 3 and 5, performs Technology leads to multifaceted problems. For example, there is a waste of the hearth zone, whereby the effective furnace area is reduced. Because of the uneven combustion, the life of the furnace lining material is further increased shortened · So it was found that on one side of the stove the tendency to ignite or There was a burning sensation while the other side was in a smoldering or smoldering state, i.e. on one Side of the furnace the material under treatment is placed on a stove in a burning state while it is on the other side of the stove did not reach the burning state until it moved to a lower hearth. Consequently there was a burn on one side of the hearth while the other side was still drying out the material. This created difficulties in controlling the residence time on the various herds and made it practically impossible to target the burners and the atmospheric conditions including the turbulence in each hearth to control that a clean distribution of the gas occurred over the stove. This consequently led to overheating of the material in some oven zones and underheating in other zones, which is a bad thing for some treatments Product. An attempt to roast zinc sulfide to obtain zinc oxide resulted in zinc sulfate, for example, which is difficult to remove from the oven. In addition, it goes without saying that a clean burn throughout Hearth zone a better heat transfer and thus a more economical one Bringing utilization of the fuel. In connection with the treatment of waste or sewage sludge prevented a clean combustion over the entire stove the emission * lies

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of odorous substances and the formation of blue smoke or tar that is too fine to pass through at present to be removed from the daily scrubber. This further reduces the need to provide afterburners or even switched off, which were previously necessary in order to comply with the legal requirements, such as the Environmental Protection Agency's Visual Appearance Code, meet.

In order to create an even distribution of the material to be treated over the stove according to FIGS. 3 and 5, a device is provided provided to separate the circumferential vector or the circumferential component of motion of the material with respect to the radial Vector or the radial component of motion. In Figs. 6 to 9 the two upper hearths of the oven are shown, the stirring teeth 36 to the longitudinal axis of their respective stirring arms are inclined so that they constitute a substantial part of the radial component 60, FIG. 3, or 82, FIG. 4, of the movement of the material to be treated on the herds. As best seen in Figures 7 and 9, there are adjacent agitator arms 32 connected with agitator chains 86 to a substantial part of the To create circumferential component 62, Fig. 3, or 84, Fig. 5. This means that the stirring teeth serve as a means of controlling the Radial movement and the chains as a means of controlling the circumferential movement of the material on the hearth. Therefore serves the careful coordination of the inclination of the agitator teeth and the arrangement of the agitator chains in order to avoid dead zones in the solid material to be distributed uniformly over the hearth when the central shaft 28 in the direction of arrow 88 according to FIG and 9 is rotated. Each end of a stirring chain 86 is thereby attached to a stirring tooth 36, in which a shackle 90, Fig. 8, is guided by a ring nut 92, which with the stirring tooth

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is connected by a nut 94 and screw 96. The chains are laid so that one end is close to the perimeter of the agitator arm and the other end is attached to the inner end of the next adjacent agitator arm. the The chain sags a little, but not enough that it drags on the stove floor. When installing the chain, the Screw 96 a gap on the order of about an inch leave so that an adjustment is possible by turning the screw. A 6.25mm chain with a total length of about 3.2 m is suitable for a furnace with an outside diameter in the range of about 6.7 m Agitator teeth 36 act independently of the chains 38 when the central shaft is rotated, but with the combination of the two components acting on the material to be treated this brushes evenly over a hearth to a drop hole, where the material passes through to the next lower lying hearth falls and is then again evenly brushed over this hearth to its drop hole and this process continues successively from the top to the bottom of the furnace.

In the embodiment of the invention according to FIG. 10 is a Agitator chain 98 is provided, one end of which is attached to the agitator arm 36 arranged on the outer circumference of the agitator arm 32, as indicated by the Reference numeral 100 indicated, while the other end of the chain is connected to the central shaft 28 at 102 will. The chain 98 is also arranged with a certain slack, which, however, is not so great that the chain grinds on the hearth base 22. Accordingly, when the central shaft 28 is rotated, as indicated by the arrow 104, acts the agitator chain essentially as a peripheral flow component and act the stirring teeth, which are concerned with the longitudinal axis of their

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Agitator arms are inclined, essentially as a radial flow component on the solid material and thus create an even and uniform material distribution over the Hearth base 22 without the formation of dead zones. Although Fig. 10 shows a single flow hearth is the inventive concept this embodiment in the same way on an outflow hearth applicable.

Fig. 11 shows an embodiment of the invention with a A plurality of agitator chains 106. Each chain is connected at one end to an agitator tooth 36, as at 108, and the other The end of the chain drags behind the tooth on the floor 20 of the outflow focus. The length of the chains decreases progressively from the circumference of the hearth base to its center. When the central shaft 28 is rotated in the direction of the arrow 110 bring the agitator teeth 36 inclined with respect to the longitudinal axis of their respective agitator arms a radially outwardly directed Flow component on the material, while the agitator chains 106 the independent circumferential component of the material flow create, so that thereby a uniform and uniform distribution of the solid material to be treated over the hearth floor without dead zones. The agitator chains 106 in this embodiment of the invention are preferably only used on a discharge hearth.

In the embodiment of the invention according to FIG. 12, the stirring teeth 36, which correspond to the longitudinal axes of their respective Agitator arms are inclined to move a substantial portion of the radial component of the material to be treated above hearth 22. Between adjacent agitator arms 32 extends, for example, from the points 114 and 116, a cable 112, the one Variety of paddles 118 carries as a means for

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Generation of a substantial part of the circumferential flow component of the material to be treated on the stove. Thus brings the appropriate adjustment of inclination of the stirring teeth and arrangement of the cable 112 coordinated and independent Control of the radial and circumferential flow components of the material to be treated so that it is uniform and is evenly distributed over the hearth base 22 without the formation of dead zones when the agitator arms 32 by means of the central Shaft 28 can be rotated in the direction of arrow 120. Although Fig. 12 shows a single-flow hearth, the concept is that Embodiment can be applied in the same way to a discharge hearth.

Fig. 13 shows a further device for evenly and uniformly distributing the material to be treated via the hearth base 22. In this exemplary embodiment, the stirring teeth 36 are again associated with the longitudinal axes of their respective ones Mixer arms tilt and create a substantial portion of the radial flow component of the material on hearth 22 while a stir bar 122 acts as a separate or independent device to create a substantial portion of the circumferential Flow component of the material is used. The stir bar 122 is attached to the leading edge of the stir teeth at 124 and extends radially from near the center of the hearth to the periphery thereof. The vertical height of stir bar 122 is hanging on the desired size of the circumferential flow component for the material to be treated. At most facilities there will be some flow of material above and below the rod. With some facilities, however, it may it may be desirable that there is a flow only under the rod. By carefully choosing the inclination of the stirring teeth 36 and the height of the stirring rod 122 results in a coordination

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and independent control of the radial and circumferential flow components for the material being treated so that this is evenly distributed over the hearth base 22 without dead zones when the agitator arms 32 are pushed through the central shaft 28 can be rotated in the direction of arrow 126. Although Fig.

13 shows a single-flow hearth, it should be understood that the same Concept is applicable to a discharge hearth.

In the following embodiment of the invention according to FIG.

14, a single-flow hearth 22 with a central downhole 26 is shown. The stirring arms 32 carry stirring teeth 36, which like are usually inclined to the longitudinal axes of their respective agitator arms and essentially the entire radial flow component for the material to be treated. As a separate independent facility to create the extensive flow component for the material are provided on alternating stirring arms 32 'stirring teeth 128, which are not inclined, but extend substantially parallel to the longitudinal axis of their agitator arms. By suitable selection of the number and the distance and the inclination of the stirring teeth 36 and the number and spacing of the stirring teeth 128 can be coordinated and provide independent control of the radial and circumferential flow components for the material being treated so that this is evenly distributed over the hearth base 22 without dead zones and the desired material residence time is present when the agitator arms 32 or 32 'are rotated by the central shaft 28 in the direction of arrow 130. Although Fig. 14 relates to a single-flow hearth, the concept of this embodiment is similar applicable to outflow stoves.

Furthermore, it goes without saying that the first or top

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The hearth of the oven can be either an inflow or an outflow. It may be necessary when treating certain materials be that only the means to separately control the radial and circumferential flow components for the movement of the material are placed on the first or top hearth or the first and second top hearths as soon as Once the material has been uniformly distributed over an upper hearth, so has the uniform distribution remains with the following lower herds. When treating other materials, however, it may be possible it is not necessary to provide such means for controlling the material flow components on the first stove, but to arrange these means for controlling the flow components on one or more other herds below. The principles of the invention are also applicable to an oven with a single hearth, in which there is either a radial inflow or outflow of the material to be treated.

The described device for controlling the radial and circumferential material flow components separately is in particular suitable for treating waste material such as sewage sludge.

Some urban communities require the sludge to be dried for part of the year, whereby the remaining ingredients are used as fertilizers. If there is no question of fertilizer utilization, then will at other times of the year the mud is dried and ashed or burned. The principles of the present invention apply to both drying and drying and ashing processes applicable. According to the invention this is

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the wet sewage sludge is continuously fed into the upper end of the furnace, the sludge of a first zone in the upper end Part of the oven is fed to dry by placing the sludge over one of the top hearths with a radial flow component and at the same time is forced over this hearth with an independent circumferential flow component, so that the mud flows in a uniform and evenly distributed manner in the direction of the relevant downhole according to FIGS. 3 and 5. The sludge is then successively passed over each hearth and through the associated downhole to the next one below Hearth in the first zone is fed with the sludge in substantially the same drying state over each Stove is held. If only the drying of the sewage sludge is in question, the so dried sludge is removed from the lower end of the first zone of the furnace. In the process of having both comprises incineration and drying, the sludge dried in the above manner is transferred to a second zone in the lower Part of the furnace is fed to the incineration by the sludge successively over each hearth and through the relevant downhole passes to the next underlying hearth in this zone, with the sludge in essentially the same ashing state Remains above each hearth in the zone and provides a controlled amount of heat to more than one hearth to carry out the drying and incineration of the sludge.

The present invention therefore provides an improved method and apparatus for dispensing solid material has been created over a stove, which compared to known devices a higher work capacity and have a higher effectiveness.

Although there are some specific embodiments of the invention

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have been described for purposes of illustration, it is understood It is evident that modifications of the teaching according to the invention within the scope of protection which are readily made by the person skilled in the art of the following claims are included.

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Claims (31)

Claims 1. Oven with at least one substantially horizontal Stove, characterized in that a rotatable one runs through the center of the stove central shaft extends upwards, on which at least one extending radially outwardly over the hearth Agitator is attached, means is provided to provide a radial flow component for that on the stove to provide material to be treated and an independent device arranged to be related to the device to create a circumferential flow component for the material to create the radial flow component, see above that when the central shaft rotates, the material flow is distributed over the entire hearth area. 2. Oven with a plurality of vertically spaced stoves, characterized by a a plurality of rotatable central shafts extending through the center of the oven and through each hearth from stirring arms attached to the central shaft at a distance from one another and extending radially outwards over each Hearth extend, with alternating hearths arranged in the area of the central shaft drop bores and the other Have foci in the area of their outer circumference arranged drop bores, a device for creating a radial flow component for the material treated in the furnace on at least one of the upper hearths, and an independent one Facility to create a comprehensive - 26 - 509886/0761 Flow component related to the facility for creation the radial flow component for the material treated on one hearth, so that when the central Wave the material flow is distributed over the entire hearth area. 3. Furnace according to claim 2, characterized in that that one stove is a single-flow stove. 4. Oven according to claim 2, characterized in that that one hearth is an outflow hearth. 5. Furnace according to claim 2, characterized in that that the device for creating the circumferential material flow component from chain-shaped elements is formed, which are arranged between the stirring arms assigned to a stove. 6. Furnace according to claim 2, characterized in that that the device for creating the radial material flow component represents a large number of stirring teeth, which extend from the stirring arms to almost the bottom of the stove, the stirring teeth being relative are inclined to the longitudinal axis of their associated agitator arms to the material radially over a hearth in the direction of to force the relevant drop hole. 7. The device according to claim 2, characterized in that the means for creating of the radial material flow component a variety of The stirring teeth are that extend from the stirring arms to almost the bottom of the stove, with the stirring teeth - 27 - 509886/0761 244A641 relative to the longitudinal axis of their associated agitator arms are inclined to the material radially over the one hearth to force in the direction of the associated drop hole, and that the facility to create the extensive Material flow component is formed from elongated rod-shaped elements, which are carried by the stirring teeth and extend substantially parallel to the longitudinal axis of the agitator arms in question. 8. The device according to claim 2, characterized in that the means for creating of the radial material flow component is formed from a plurality of agitating teeth that extend from a number extending from stirring arms to almost the hearth bottom and relative to the longitudinal axis of their respective Mixing arms are inclined to the material radially over the one hearth in the direction of the relevant drop hole to force and that the establishment to create the extensive Material flow component consists of a multitude of agitator teeth that are different from the rest of the agitator arms Extending downwards almost to the hearth floor, the latter stirring teeth being essentially parallel to the Longitudinal axis of their associated agitator arm are arranged, so that the material in circumferential direction over the stove is forced. 9. Furnace with a multitude of vertically spaced Herd characterized by a rotatable central shaft extending through the center of the oven and extending up through each hearth, located on alternating cookers in the region of the central shaft si drop holes and on the other herds in the - 28 - 509886/0 7 61 " ²⁸ " 2AU641 Area of their outer circumference arranged drop bores, a plurality of agitating arms attached to the central shaft and spaced from one another, extending radially outward over each hearth, a plurality of stirring teeth extending from the stirring arms Extending downwards almost to the hearth floor, the stirring teeth being relative to the longitudinal axis of the respective Mixing arms are inclined to force the material to be treated radially over the hearth, and an independent Means to create a comprehensive flow component for that on the top hearth in a critical zone too treating material so that the material moves circumferentially over the hearth when the central shaft rotates becomes and with a rotating shaft over each complete hearth to the relevant drop hole and through this reaches the next stove below. 10. Oven with a plurality of vertically spaced stoves, characterized by a rotatable central shaft that extends through the center of the oven and up through each hearth extends, drop bores arranged in the area of the central shaft on alternating foci and in the area the outer circumference arranged drop bores on the other herds, a plurality of at a distance from one another lying agitator arms attached to the central shaft that extend radially outward over each hearth, a multitude of stirring teeth that extend down from each stirring arm almost to the bottom of the hearth and are inclined relative to the longitudinal axis of their respective agitator arms about that under treatment To force material over the herd, * a stirring chain that * and - 29 - 5 0 9 8 8 6/0761 -29- 244A6A1 is arranged between the stirring arms, which are assigned to the uppermost hearth, around the material in the circumferential direction to move over the hearth when the central shaft rotates, so that the material flow when the shaft rotates over every whole hearth to its associated drop hole and thereby falling down onto the next stove below. 11. Oven according to claim 10, characterized in that that a device for adjusting the tension is provided for each agitator chain. 12. Oven according to claim 10, characterized in that that each agitator chain with one end at the outer end of a agitator arm and with its other end is attached to the inner end of the adjacent agitator arm. 13. Oven according to claim 10, characterized in that that one end of each agitator chain with the central shaft and the other end of the chain outside the Center is connected by a paddle. 14. Furnace with a multitude of vertically spaced Stoves, characterized by a rotatable, extending through the center of the oven and central shaft extending upwardly through each hearth, arranged in the region of the central shaft Drop bores on alternating herds and drop bores arranged in the area of the outer circumference on the other flocks, a variety of spaced apart - 30 - 509886/0761 24U641 paddle arms attached to the central shaft and extending radially outwardly over each hearth, one Large number of stirring teeth that extend from the stirring arms to almost the bottom of the stove and relatively are inclined to the longitudinal axes of the agitator arms concerned in order to radially over the material to be treated To force the topmost hearth in the direction of the associated drop hole, and a multitude of chains, each with one free end and one end, which is connected to the stirring teeth, in order to move the material in the circumferential direction over the Forcing the uppermost hearth so that when the central shaft rotates, the material flows over each entire hearth area distributed to the relevant drop hole and thereby falling down to the next hearth below will. 15. Furnace with a multitude of vertically spaced from each other arranged stoves, marked by a rotatable through the center of the oven and central shaft extending upwardly through each hearth located in the region of the central shaft Drop bores on alternating foci and drop bores arranged in the area of the outer circumference the other flocks, a plurality of spaced-apart agitator arms attached to the central shaft, the extending radially outward over each hearth, a multitude of stirring teeth extending from the stirring arms up extend almost down to the hearth base and are inclined relative to the longitudinal axis of the agitator arms in question to force the material radially over the uppermost hearth in the direction of the associated drop hole, and a cable - 31 - 509886/0761 - 31 - 24U641 with a plurality of spaced-apart blades, with the cable between the topmost Hearth associated stirring arms is arranged to the material in the circumferential direction over the uppermost hearth force, so that when the central shaft is rotated, the material flows over each entire hearth area to its own assigned drop hole and thereby falling down is distributed to the next hearth below. 16. Furnace with a multitude of spaced vertically arranged stoves, marked by a rotatable through the center of the oven and central shaft extending upwardly through each hearth, located in the region of the central shaft Drop bores on alternating herds and drop bores arranged in the area of the outer circumference on the other flocks, a plurality of spaced-apart paddle arms attached to the central shaft, which are Extending radially outward over each hearth, a multitude of stirring lugs extending from the stirring arms of the uppermost hearth extend downwards and are inclined relative to the longitudinal axis of the respective agitator arms to force the material radially over the first hearth in the direction of the associated drop hole, and elongated, rod-shaped elements which are carried by the stirring teeth and are essentially parallel to the longitudinal axis of the agitator arms concerned extend in order to move the material in the circumferential direction over the uppermost hearth, so that when the central shaft rotates, the material flow is distributed over each entire hearth area. - 32 - 509886/0 7 61 2ΑΑΑ6ΑΊ 17. Oven with a plurality of vertically spaced stoves, characterized by a rotatable one extending through the center of the oven and up through each hearth central shaft, drop bores arranged in the area of the central shaft on alternating foci and arranged in the area of the external circumference Drop bores on the other herds, a plurality of spaced apart ones attached to the central shaft Stirring arms extending radially outward over each hearth, a plurality of stirring teeth extending from alternating agitator arms on the uppermost hearth extend downward and relative to the longitudinal axis of the agitator arms in question are inclined to the material radially over the uppermost hearth in the direction of the associated drop hole force and a multitude of teeth on the other stirring arms on the topmost stove that extend down from the relevant stirring arms extend, the latter stirring teeth substantially parallel to the longitudinal axis of the respective agitator arms and move the material in the circumferential direction over the uppermost hearth so that When the central shaft is rotated, the material flow is distributed over each entire hearth area. 18. Method of material treatment in an oven with a single hearth with a central shaft extending up through the center of the hearth, and at least one paddle is attached to the central shaft and extends radially outwardly over the hearth extends, characterized in that the material is placed on the stove, the material - 33 - 509886/0761 24U641 over the hearth with a radial flow component and at the same time with an independent circumferential flow component forcibly moved so that the material over the entire hearth area without the formation of dead zones is brought into flow. 19. Method of material treatment in an oven using a plurality of vertically spaced apart flocks with a central rotatable shaft extending through the center of the oven and up through each hearth, a plurality of spaced apart mutually arranged on the central shaft agitator arms are provided, which extend radially outward over each hearth extend, in the area of the central shaft drop bores are arranged at alternierendai herds and in the area the outer circumference of the other herd provided drop holes are, characterized in that the material is introduced at the top of the furnace, the Material over one of the upper foci with a radial flow component and at the same time the material over the a hearth with an independent peripheral flow component forcibly moves so that the material over the entire area of the one hearth flows in a distributed form in the direction of the relevant drop hole, and that you successively the material over each hearth below one hearth and through the relevant drop hole leads to the next lower stove and withdraws from the lower end of the oven. 20. The method according to claim 19, characterized in that the radial flow component - 34 - 509886/0761 24446A1 A flow component directed radially inward is over the one hearth. 21. The method according to claim 19, characterized in that the radial flow component over the one hearth is a radially outward flow component. 22. Method of sewage sludge treatment in a furnace with a plurality of vertically spaced from each other arranged stoves, a rotating central one, running through the center of the oven and through each stove shaft extending therethrough, a plurality of spaced apart fixed to the central shaft Agitating arms, which extend radially outward over each hearth, are arranged in the area of the central shaft Drop bores on alternating herds and drop bores arranged in the area of the outer circumference on the other herds, marked by the fact that the wet sewage sludge is at the top of the Oven introduces the wet sludge downwards through the oven for drying by moving the sludge over one of the uppermost foci with a radial flow component and at the same time over the one focal point with an independent one circumferential flow component is forcibly moved, so that the sludge over the entire area of the one hearth in a distributed form in the direction of the downhole in question and that one successively the mud over each hearth below the one hearth and down through the relevant drop hole - 35 - 509886/0761 leads to the nearest hearth, keeping the sludge in essentially the same drying condition Qn of any given diameter around each hearth in the oven, and applying a controlled amount of heat to more than one hearth to dry the sludge. 23. Method of sewage sludge treatment in a furnace with a plurality of vertically spaced from each other arranged stoves, a rotating central one, running through the center of the oven and through each stove shaft extending therethrough, a plurality of spaced apart fixed to the central shaft Mixing arms that extend radially outward over each stove extend, in the area of the central shaft arranged drop bores on alternating foci and in the area the outer circumference arranged drop bores on the other flocks, characterized in that that one enters the wet sewage sludge at the top of the furnace, the wet sludge of a first zone in the upper part of the oven for drying by placing the sludge over the uppermost hearth with a radial Flow component and at the same time with an independent circumferential flow component is forced to move, to distribute the mud over the entire area of the top stove in the direction of the concerned Drop hole to flow and successively pour the mud 'over each hearth below the top hearth and through the downhole in question leads to the hearth below in the first zone, whereby the mud is in essentially the same drying state for everyone - 36 - 509886/0 7 61 a certain diameter around the hearth in the first zone, and the thus dried egg sludge in a second Zone in the lower area of the furnace for incineration by passing the sludge successively over each hearth and get through the relevant drop hole to the next underlying hearth in the second zone leaving the sludge in substantially the same ashing state at any given diameter around each stove in the second zone and holds more than one stove in a controlled amount for drying and Ashing the sludge adds heat. 24. A method of treating material in a furnace with a Plurality of vertically spaced flocks, one rotatable through the center of the oven and through each hearth extending central shaft, a plurality of spaced apart paddle arms attached to the central shaft and extending radially outwardly over each hearth in the area the central shaft at alternating herd-arranged drop bores and in the area of the outer circumference at the other herds arranged drop bores, characterized in that the material at the top At the end of the oven, with a multitude of teeth protruding from the mixing arms on the uppermost hearth and it forcibly moves over the top hearth with a radial flow component while simultaneously Chains are drawn through the material between the adjacent stirring arms assigned to the uppermost hearth are arranged to apply a circumferential flow component to the material on the uppermost hearth, - 37 - 509886/07 6 1 244A641 so that the material is distributed over the entire area of the top stove in the direction of the corresponding drop hole flows, and that one successively the material over each hearth below the uppermost hearth and through the relevant drop hole to the next hearth below and from the lower one The end of the oven peeled off. 25. The method according to claim 24, characterized in that the chains are between the the innermost tooth on one agitator arm and the outermost tooth on the adjacent agitator arm. 26. The method according to claim 24, characterized in that the chains are between the outermost tooth of an arm and the central shaft extend. 27. The method according to claim 24, characterized in that the chains of the relevant Teeth are tightened. 28. Method of material treatment in a furnace with a plurality of vertically spaced from one another
arranged cookers, a rotatable central shaft extending through the center of the oven and through each hearth, a plurality of spaced-apart stirring arms attached to the central shaft and extending radially outwardly over each hearth, alternating in the region of the central shaft Foci arranged drop holes and in - 38 509886/0 7 61 Area of the outer circumference of the other herds arranged drop bores, characterized in that the material is at the top At the end of the oven, with a multitude of stirring teeth protruding downward from the stirring arms in the uppermost Hearth in a critical zone and it through the top hearth with a radial flow component and at the same time forcibly moved with a circumferential flow component, so that the material over the entire area of the uppermost hearth in a distributed form in the direction of aif the associated drop hole flows, and that the material is passed over each hearth below the uppermost hearth and through it Drop hole leads to the next stove below and pulls it off from the lower end of the oven. 29. A method of treating material in a furnace having a plurality of vertically spaced apart Stoves, one rotatable, going through the center of the oven and up through each stove extending central shaft, in the area of the central shaft arranged drop bores on alternating Herds and drop bores arranged in the area of the outer circumference on the other herds, a large number of at a distance from each other attached to the central shaft agitator arms, which extend radially outward over each Hearth extend, a multitude of stirring teeth that extend from the stirring arms to almost the bottom of the stove extend below and are inclined relative to the longitudinal axis of the agitator arms concerned, and with elongated, rod-shaped elements held by the stirring teeth - 39 - 509886/0761 24U641 are and are substantially parallel to the longitudinal axes of the agitator arms in question, characterized in that the material Enters at the top of the oven, distributing the material over the entire area of the top stove Shape moves by the radial flow component due to the inclination of the stirring teeth to the longitudinal axes of the respective Agitator arms and the circumferential flow component is created by the rod-shaped elements, and that the material is allowed to fall through the drop hole onto the stove below. 30. The method according to claim 29, characterized in that the circumferential flow component controls by adjusting the height of the rod-shaped elements. 31. A method of treating materials in an oven having a plurality of vertically spaced ovens, a rotatable central shaft extending through the center of the oven and up through each oven _; drop bores arranged in the area of the central shaft on alternating stoves and in the area of the outer circumference arranged drop bores on the other stoves, a multiplicity of stirring arms attached to the central shaft at a distance from one another, which extend radially outwards over each stove, a multiplicity of stirring teeth , djevon alternating agitator arms protrude almost down to the hearth base and are inclined relative to the longitudinal axis of the agitator arms in question, and 509886/076 1 24U641 Stirring teeth that from the other stirring arms up almost protrude down to the hearth base and are essentially parallel to the longitudinal axis of the agitator arms concerned, characterized in that one enters the material at the top of the furnace, the Material moves over the uppermost hearth in the direction of its downhole, taking into account the radial material flow component due to the inclination of the stirring teeth on the alternating stirring arms and the circumferential material flow component generated by the material contact zone of the stirring blades carried by the other stirring arms. 509886/07 61