DE1914372C3 - Method and device for producing bodies from expanded clay or the like - Google Patents

Description

The invention relates to a method of manufacture Od of bodies made of expanded clay converted to a ceramic bondable state on the surfaces, up to at least partial Filling the gaps between the granules and deformed into a one-piece body be bound, as well as a device for producing bodies from expanded clay od. Like.

It is known to manufacture granules of spherical shape from clay and suitable aggregates, which inflate with subsequent temperature treatment, but through on the outer surfaces a burning skin are tightly closed. Such expanded clay granules or expanded clay balls are characterized above all by a very low volume weight. As is well known Such expanded clay balls are made into lightweight construction elements by bonding with mineralogical ones or organic binders. It is also known to use expanded clay bodies through ceramic Form binding of the individual expanded clay balls. In this case, the highly heated ones produced in a known manner Expanded clay granules filled into molds and compressed by mechanical pressure, whereby both intimate contact with the granulate surfaces and deformation of the individual Granules takes place through which the between the granules in the Urs; leakage areas in the state of repair fill out. This results in uneven compression.

The expanded clay bodies lost in such attempts have a number of disadvantages. Your density, based on the reduced volume, is greater than the volume weight of the previously larger volume heap of expanded clay balls, because a partial elimination of the bulky structure occurs during compaction. The structure of this Expanded clay body is also irregular, because the expanded clay balls to the ceramic bond with so high temperatures are withdrawn from the rotary kiln that they are not dimensionally stable. Unei-wish Deformations of a number of these expanded clay balls are therefore unavoidable.

The strength of such expanded clay bodies is also considerable affects, among other things, because it is impossible to determine the warmth of the individual to control withdrawn from the rotary kiln granules so that their surface evenly up to a certain layer depth is reached up to the state capable of ceramic bonding. Also through the Subsequent transport and handling of the granules outside the rotary kiln arise Cooling that leads to the fact that the ceramic bond is uneven. These irregularities the structure as well as the structure-related properties, such as strength or thermal insulation, are the Uriiiche that such expanded clay bodies can only be used in sheet form in exceptional cases. The thickness of such an expanded clay body produced in a known manner must be such To be able to compensate for the disadvantages, it is always greater than the static or thermal requirements is necessary with a uniform structure.

Significant disadvantages arise above all in the production of the known expanded clay bodies. Substances containing clay minerals stick at temperatures which are in the melting range, on metal surfaces if these are also heated to a high level are. In the compaction in presses required for the production of expanded clay bodies, the Surfaces of the expanded clay balls at least three-dimensional,

s if not belly melt, and those with them Metal surfaces that come into contact must be in order to avoid impermissible cooling of the Expanded clay balls are at approximately the same temperatures.

ίο The adhesive effect between metal and expanded clay does not end again until both have cooled down to temperatures in the range of 500 ° C. To the expanded clay body To be able to take undamaged from the forms used for compaction must therefore

It is first necessary to ensure that the temperature of the expanded toa body is lowered to 500 ° C and below. Such a way of working is not only time-consuming, but also associated with a loss of energy; because the forms

so and other device parts that come into contact with the granulates to be processed, must, in order to avoid animals inadmissible cooling before compaction, each time before the next Pressing process can be heated again.

As for the reasons mentioned, only expanded clay bodies of considerable thickness can be used in practice are produced, which after their production by means of suitable saws into smaller blocks or plates are cut. The cost of this dismantling of the blocks is undesirably high and the surfaces are not smooth.

In order to avoid the described disadvantages of the known production of expanded clay bodies, was also tried to introduce unexpanded granules into molds, to close these molds and that Granules inside these molds ^ .arch warming to expand and also to bond with each other ceramic.

Since the granules inside the molds when

Blähvorgai and the associated increase in volume cannot evade, the granules are pressed against each other with the contact surfaces and ceramically bonded as soon as the surfaces are heated to correspondingly high temperatures. The granules enclosed in the molds should be heated from the outside by heating the Mold walls take place. Since expanded clay granules are extremely poor heat conductors, this The proposal will not be economically viable in practice. It would be one of the Mold wall to the first granulate layer already strong, from the first to the next and the following Layers in the mold, however, result in a very steep temperature gradient. The result would be consist in the fact that the granules lying directly on the mold ring are already overheated are molten before those in the middle area. Granules located at all at the expansion temperature or ceramic bondable temperature are heated. Apart from these disadvantages, this proposal would also be uneconomical as a result high expenditure on molds and the result of long heating times and long cooling times given low production output will not be economically viable.

In order to avoid the disadvantages described, the invention is based on the object of a method and a device for producing expanded clay bodies to create, which is easy to

wall can be carried out quickly and expanded clay bodies transfer from the gas to the granulate

supplies, which have a uniform structure, the gas temperature needs large amounts of moving gas.

The solution to this problem is at best slightly above the one to be achieved with the one

conductive mentioned method according to the invention is to be the temperature of the granules. This is particularly-

that the expandable granules are approximately uniform in terms of the devices and equipment

prefer size that is very advantageous to either a manufacturing device; because the gas temperatures can

taken directly or from a storage container thereby below the softening point of the

are, first held in a molding box as a pile of metals used as the device

be brought in and then the heap with it.

Highly heated gas alternately from opposite. It is also important, however, that a short-term lying sides controlled, briefly until the heating of the granulate is reached. That means, range one thing at least essentially the same that the granulate predominantly on its outer surface ceramically bondable condition of the surface and as a result of the possible control of all granulates up to the onset of the expansion process of the gas flow, also only up to a very specific one Blow through and the pile relentlessly supports the 15 layer depth to the selected temperature is, whereby the expandable granules are heated in and therefore only in this area in one <expand the free gaps and to a plastic, ceramic-bondable state over the body from ceramic-bonded granules disappears, in which the touching surfaces are cleaned up will. connect surfaces of the pile. There is therefore a

In this process, the granules are ao precisely controllable ceramic bond. As a result

mechanically stable condition. One of the unyielding molding boxes Can the heap

Destruction of the inflatable structure is therefore avoided. Do not evade any further either, but one occurs

The filling of the molding box consists of a bond on the surfaces in contact with one another

Debris that is permeable to gas. The warming one

the granules are made using this own temperature, which is heated in a way that is new at least for this application in the manner described except for the softening area, namely by blowing through them, and can be heated more Gases that are guided in such a way that the frequency and the percentage of the granulate surface are evenly flowed through. This determines which ceramic bond is formed with the granulate bodies adjacent to the granulates almost on all sides of the gas a! S 30. Is the he-heat carrier washes around and heated. Naturally, the heated layer of the granulate body is very thin, for example, at the temperature of the surface that is set, then between the individual granulate of the granulate initially only low melt bridges form into the pile at the highest, and it turns out to be formed with a cross-section. If, on the other hand, a certain temperature or to a greater depth is heated due to the gas flow, then a temperature gradient will increase. To reduce this gradient, a strong bloating process sets in, and the individual becomes there. Gas alternately in opposite granular bodies puff up to an almost full direction through the pile. So the constant merging of their surface very quickly results in an almost uniform temperature of all and lose their spherical shape in the process.
Granules of the heap. 40 It is therefore important that with the new procedure

Before that, the granulate is on the gas inlet side of the pile, which is not moving during the ceramic bond, on a high, highly heated, pyroplastic state very close to the inlet temperature of the gas and is thus hotter than external force is exerted, but that it is desired by; for the inlet temperature must be at least slightly higher than the temperature to which the granulate is simultaneously expanded and the granulate is to be heated. This excess temperature results in a perfect, homogeneous structure of the granulate in the outer zone of the heap structure, which, however, only exists for a short time; because with the ability and uniform strength values, the next change in direction of the gas flow is achieved. However, it also arises as a result of the lack of gas flowing through this outer zone that had previously passed through the entire pile of material due to the application of external mechanical force. As a result, granules also expanded a very small space, the temperature of this exiting gas flow weight of the expanded clay body produced; because, depending on the prevailing in the core of the pile, no expansion pore structure is compressed again by external influence, temperature of the granulate to a greater or lesser extent, namely pressure,
below the inlet temperature, under certain circumstances even Ef, there is also the possibility of the production process under the desired target temperature of the granulate being very differentiated in terms of and thus under the temperature that controls the grain on certain microstructures. When the outer zone of the pile has already become narrow, for example for a given purpose. The temperature of the granulate of the 60 melt bridges between the individual granulate-external zones of the pile will therefore again be sufficient to lower a certain strength. As a result, a temperature mean is to be ensured, but in addition to the value which is close to the desired temperature, the expansion rate given within the granulate, which the granulate is to be heated, is anyway. Pore structure a superordinate, very hollow-brown

The process gains the greatest condition that a rich structure of gaps is desired, then needed

by that, due to the always controllable gas flow, the expansion process of the expediently only to a great extent

and the very large contact area between the thin surface layer of heated granulate only

Gas and the granulate a very intense heat borrowed at the appropriate moment, z. B. by reducing

change in the supply of heat to be interrupted. nen or one outside the flow-through chamber

If there are thin melt bridges between the granules - usable solid cover is included.

bodies ensure the desired strength, the advantages of the procedure already mentioned

However, a largely void-free structure according to the invention can be found in the embodiment of

is to be achieved, then the pile after s device is their precipitation. Leave the granules

End of the heating due to the bulging gases which heat up very quickly after the extension Given the opportunity to stop the inflation process relatively quickly from the flow-through chamber.

use of the coolness stored as a result of thermal inertia. That in turn means that the educated

Continue heating in the desired manner until the expanded clay body without disadvantages only at temperatures Gaps between the individual granules are formed below 500 ° C and so the sticking

bodies are filled. the expanded clay on metal parts, e.g. B. molding box parts,

The particular advantage of the process is that there are no repercussions at temperatures above 500 ° C.

not only in the fact that previously unattainable qualities can cause parts.

of the expanded clay body produced can be achieved because only a very small temperature gradient, but above all in the honing production process, the gas and the heating power to be set and which is necessary in comparison to the previous level of the granules, can even with known processes with low energy consumption. Granules made from clay with a relatively high melting point

The process also allows the production of known molding box materials to be carried out, the expandable granules and the expansion to the end state spatially and temporally separated, ao molding box located heap on simple It can be done, for example, in a pre-dried, unexpanded manner, the device is Granules used to form the heap further designed so that the Duirchströmkammer are, however, the volume of which is essentially provided for receiving the molding box must be less than the middle part of the expanded clay body to be produced and two at the top of the mold. If, on the other hand, already pre-expanded grass becomes the underside of adjoining pressure equalization chambers nulate is used, then the heap can have that which is controlled, for example by means of volume equal to the volume of the expanded clay flaps to be produced, with the return in a circular manner have body. highly heated gas to the burner with the gas

If the process is continued, the outlet opening of the burner and / or with the surrounding

consisting of ceramic-bound granules 30 giving atmosphere can be connected.

Expanded clay body on at least one surface. The pressure equalization chambers ensure that

mechanically smoothed or with a pattern, the requirements are met in order to

see. technical way of uniform heating of the

To achieve certain surface qualities pile in the molding box. Through this,

the expanded clay body 35 produced by the process that these pressure compensation chambers as small as possible

if the process is continued, thermal inertia appearances

due to the fact that the vitrified gene is reversed when the direction of flow is reversed

Avoid expanded clay bodies on at least one surface.

a surface material, such as a glaze mass, is a further embodiment of the device is coated, which is then characterized by the body 40 in that the heat inherent in pressure equalization and / or by a post-chambers in the area of the central part one of the following heat treatment baked or molded box have a corresponding cross-section is sintered. and tapers conically in the direction of the central part

The granules, some of which are responsible for the formation of the intumescent.

Clay bodies can be assumed to be pretreated in different ways. This includes chambers being fluidically relatively high z. B. the mixing with fiber material or the speeds achieved, which is a prerequisite Mixing and / or coating mil ζ. B. metallic are that deposits, especially soot-like substances. In this way, »Bläp with ferro- deposits on the walls of the pressure magnetic Eicten, electrically conductive 50 equalization chambers can be avoided, speed and / or higher-level spatial, for example to achieve uniform heating of the strength-increasing Fas can be created. Granulate is the device in the way further-

It should also be mentioned at this point that it is formed that between the pressure compensation chamber!]

the preceding statements and the following and the middle part each have a flow resistance

the explanations and the description is arranged from 55 to the highly heated gas over the

finally on expanded clay as the material for the granular surface of the molding box or the

refer to late, but to distribute accordingly also to borrowed pile,

Their expandable and ceramic materials are, in a further development of the device is before

such as expanded slate, are applicable. seen that the flow resistances, except

The device for performing the method fc men in the edge and corner areas, uniform

is characterized according to the invention that have flow cross-sections and that di <

a through-flow can for guiding in a through-flow cross-section of the molding box edges

Burner high-temperature gas as well as to accommodate the opposing areas larger than normal, dii

With this gas to be heated pile provided through-flow cross-sections of the molding box corner

is, with the pile in a movable mold- 65 opposite areas larger than in the edge

Box with massive rope walls and sieve-like areas are designed to ensure a uniformly!

perforated bottom as well as an option to achieve heat transfer to the pile,

the throughflow chamber usable breakthrough In this embodiment of the device win

ie
a I-

taken into account that at the edges of the molding box, but especially at the Corners, a greater temperature gradient occurs than in the central areas.

In an expedient development of the device, the flow resistances are made of clay granulate balls educated.

It is known that the presence of oxygen can question the swelling process, so that the swelling only occurs at higher temperatures or is greatly increased or does not take place at all.

In order not to heat the granulate in the molding box with the combustion gases, we recommend The use of a further embodiment of the device, which is characterized in that the burner is equipped with a heat exchanger and that the heat exchanger, the two Pressure equalization chambers and the middle part of the flow-through chamber form a circular flow »o enable a flow path for an oxygen-free, at least low-oxygen, highly heated gas, with in the flow path a fan or the like is switched on to circulate the gas.

It has been shown that the lowest limit for * 5 the size of the granules is about 10 mm in diameter and that above a size of 2 (mm diameter it is hardly possible to achieve satisfactory results.

With a device of this type it is to the exact 3 " Control of the heat transfer in the individual flow-through chambers is expedient if each flow-through chamber apart from the connection with the neighboring ones, which is necessary for the one behind the other Has an additional controllable connection with the burner through-flow chambers.

Another solution to the last-mentioned object is in an apparatus for producing Bodies made of expanded clay or the like. Achieved in that several through-flow chambers each with two * o Pressure equalization chambers and a middle part in between are arranged parallel to one another and can be connected to a common burner in a controlled manner.

To solve the problem, several expanded clay bodies * 5 to produce at the same time, is a device for producing bodies from expanded clay od. Like. So designed that several throughflow chambers in a common flow path one behind the other are arranged. 5 <>

When arranged one behind the other, several Flow chambers run through this conveyor and the flow direction of the gas from one Flow chamber to the next and the conveying direction of the conveyor is opposite to each other be.

An advantageous development of this device is that all are arranged in parallel Flow chambers have a common central part. ^

It is useful if the common middle part of the parallel flow chambers in its dimensions for the simultaneous inclusion of several small molding boxes or for the Dimensions of a single large molding box is designed.

Each through-flow chamber can have control flaps for more uniform heating of the granulate.

in order to be able to briefly reverse the flow direction of the highly heated gas in a controlled manner.

It is also useful if a conveyor for molding boxes, which is partially designed as a roller conveyor or for expanded clay bodies, starting from a filling station, through one or more flow-through chambers, a demolding station and at least one post-treatment station runs.

Such an aftertreatment station can for example be designed so that for aftertreatment the expanded clay body is provided with a heated smoothing roller.

This pair of smoothing rollers is necessary above all if expanded clay bodies smooth on all sides are desired. This achieves that the irregularities on the expanded clay body due to the perforated, sieve-like molding box parts are eliminated by the subsequent smoothing.

Another expedient design of an after-treatment station is characterized by this. that at least one heated embossing press is provided for post-treatment of the expanded clay bodies.

Using such an embossing press, certain surface patterns can be created on the expanded clay body be generated.

To avoid sticking, all metal surfaces, those with granules or the expanded clay bodies formed from them at temperatures above 500 ° C come into contact, with a separating compound made of preferably higher melting material be coated as the clay of the granules or expanded clay body.

Embodiments of the method and the devices for its implementation are in the following is explained with the aid of schematic drawings.

F i g. 1 shows a schematic view of the elements required to carry out the manufacturing process Workstations, namely storage containers. Molding boxes and flow-through chamber;

Fig. 1a and Ib show the putting on and the Removing the cover plate for a molding box before and after passage through the flow-through chamber;

Fig. Ic shows the arrangement of the demolding station;

F i g. 2 and 2 a show the arrangement of smoothing rollers or an embossing press for post-treatment the expanded clay body;

F i g. 3 shows a flow-through chamber with a downstream heat treatment channel;

Fi g. 4 shows expanded clay bodies under a coating processing device and the downstream heating tunnel;

F i g. 5 shows expanded clay bodies in a cooling tunnel

F i g. 6 shows a molding box for carrying out the method;

F i g. 7 shows the molding box according to FIG. 6 in section;

F i g. 8 indicates the arrangement of a through-flow chamber with internals and an inserted shape box, a burner, a heat exchanger] two fans and a duct for one circular flow path of the heated gas;

Fig. ¹ ) shows a temperature diagram in which the temperature curve is plotted within the pile located in the molding box during heating during the individual flow processes;

409 683/3

Fig. 10 shows a partial section through the im Debris in the molding box at the beginning of the heating process;

Jhn-fi h · κ ^{6 '8} A ^e t ^inen n -? ^E iT ^g corresponding F ι g 12 shows the top view of several parallel

ΪΚΐΐ:, ^Du ' ^{chströmkanlmcrn in} connection with a common burner;

Fig. 13 shows several through-flow chambers

Fig. 14 shows several flow-through chambers with common center. and large format

FiV 15 «* several one behind the other Flow-through chambers with a common middle part, the requirement of the molding box m.t. indicated

des if * " ^ ^ ™ ™ ⁸ * ' *" ^

Cooling of the granules are preheated, generated but in contrast to the openwork deck I a smooth surface on the expanded clay body. At the Blowing through the perforated cover S forms a flow resistance which is avoided when the Due to the properties of the Toni, the molding box 2 moved into the flow-through chamber without a lid can be

The in

"* ϊ ^FiglC ^ ^interpreted EnSöSaTion 6 wdcne

^{Inclined A} " ^{fla has} blocks 7 for the side walls 8 and a gripper or lifting device 9 for

the "expanded clay" removed from the molding box 2

lose and as shown in Fig lc "Sen ^ au way the sloping bearing blocks 7 fall from En" - ^^ ^{6 from} ^ «« s jSil ßSonkörperio aul

late are produced in a known manner in rotary kilns or drum ovens and either drawn off from these directly or from a storage container and filled into molding boxes 2 at the filling station 1. The molding boxes 2 are expediently designed to be movable. A stripping device in the form of a stripping bar 3 (Fig. 1) and a vibrator (not shown) ensure that the Ο _Γ3 η _υ | 3ΐ ^ _{φεΓ are arranged} in the molding box as evenly and evenly as possible the pile heats up. This is done by repeatedly blowing a high-temperature gas through alternately in opposite directions for a short time. The ΟΓβηυΙβΙ ^ φεΓ are heated on their outer surfaces up to a predetermined layer depth to a state capable of ceramic bonding and form ceramic bridges with one another. At the same time, the re-inflation begins. In this ZVO Blähvorganges, the void spaces wipe each spherical Granulatkömern ausaefüllt

To prevent the heap during of the expansion process does not reach a larger spatial shape than the predetermined one, is before entering in the flow-through chamber 4 (Fig. la) a sieve-like perforated cover S is placed and according to Fig. Ib after the molding box 2 has been extended the flow-through chamber 4 or lifted off again after the completion of the bleaching process. The side walls the molding boxes are solid, while both the bottom and the lid are sieve-like must be perforated to allow the gas to flow through.

With certain clays, the expansion takes place lanesam when the required temperature is reached and delayed. With these clays, the molding box 2 can enter the flow-through chamber 4 without a cover retracted and quickly extended again when the expansion temperature is reached. before a noticeable swelling occurs. Since outside of the flow chamber 4 there is no gas permeability of the Cover is required, a solid plate can be placed as a cover to prevent that the pile expands when it is expanded beyond the predetermined spatial shape. This massive Although plate must to avoid an impermissible

the clay body

Bottom and SL toe H
Cover vtullh * '

* ₅ SSt for 2 Α

Ϊ en ί p

the diOberfchenn ^
generate! ° ^{surface area}

kästen 2 zl "? ⁶ " ^ " ^De _n ^{Ckel 5 can dic form} ' Jl? _{n pin} ^. ^eren influencing of the inflation process d Sn ^.""^» the duct 14 and

Det B _ä h · L ^ ^{Cm) ng a 'S also Kühlu "g}

3, gap r »,? ™ ^ u ^v ° L be ^{taken to the}

affects ^ granules further

the RnL Iu «\ ^gezei ^ · ^like expanded clay body 10 on lSentl, *» u ^U " ^{tCr of a} contracting device

trawrin ^ f ^hr ! _c ^w f ^rden means of such Aufauf ^ Ιηκ S ^"g u ^könnnen example glazes are F? l ^of 10 Blähtonköφer ^Achen applied""""! ^k ° can also other coatings pre-Srech πη "Ύ ^through crime or corresponds

with the!? ^{m de <? Orders} in connection

Blähtnii «iü" ⁸ ,. Passing speed of the βΧμ there ^{is the} possibility of certain

generate as ^ _p ^tu "S ^smuster ™. Zwcckmäßiger-Schirhi lit t λ genes ^on g ^etra masses that a

Form further ν ^{TÄ m expanded} body in which tldSh · conveying along the roller conveyor

welrhrrn ^{emen Heiztunne} l 17 through felt 10 in no-h "" ^Ausnutzu "g of the Blähtonkörpern lent ™ '" "^""-" ends of heat as well as by additional

aufoörf w ^{e for} S « ¹⁰ ^ * that the

SohnM! R " ^^^ sinter or melt,
sen oH * intended Oberflächenbehandlunkörne ~ tn ^ren finishing of expanded clay Rollenhah? ^ ^{s taken} md. will they be of the

I _n this "V" ^{Cmen Kühltui} "iel 18 retracted.

far eekfihh 1 ^ago I telIten ^it so Biähtcnkörper

the widths ** ^the further processing or

borrowed is ^ansport 'storage or the like required-

Fin P

He set * ° Τ ^C " ^{2 is} '" ^{Fig. 6 and 7} shown. a Rh ^{z "sam} men of massive side walls 8, sieHrt" ^U * ^"d el ^{a cover} 5. The base 20 of the? Γ ^{g durcnbr} ° chen trained and equipped with Räwiiui.

If you want to work efficiently and at high production speeds, a damage-free detachment of the molding box parts from the expanded clay body must also be possible before the Biähtonkörper has been cooled to temperatures around or below 500 ° C. Such detachment is possible without destroying the surfaces of the expanded clay body if the metal surfaces that come into contact with the expanded clay body are coated with separating compounds. The separating compounds are expediently mineral compounds such as clay, fireclay; ¹ or the like, as well as clay minerals with a higher melting point than that of the granules used.

The flow-through chamber 4, as shown in FIG. S shows two opposing conical or funnel-like pressure compensation chambers !! 23, which face each other with the largest areas and between them have a central part 24 which is intended to receive the molding box 2 in which the granules to be heated are contained. The volume of the pressure compensation chambers 23 is kept as small as possible. In the case of the in FIG. 8, the highly heated gas is blown directly into one of the pressure compensation chambers 23, controlled by control flaps 25 from this, through the corresponding position of the control flap 25, part is released into the ambient air and the other part is returned to the heat exchanger like a circuit. Fans 22a determine the direction of flow of the gas. As a result of the volume for the gas in the heat exchanger which is several times greater than that in the pressure equalization chamber 23, it is achieved that when the value shown in FIG. 8, the direction of flow of the gas, indicated by arrows, takes place in an almost identical manner in the flow chamber 4.

The inclination of the walls of the pressure compensation chambers 23 is chosen so that by the Reduction of cross-section in the direction of flow, increasing flow velocity is such a strong relative movement between the walls of the pressure equalization chambers 23 and the highly heated gas what is achieved is that deposits, in particular soot deposits on the walls, are avoided with certainty will.

An essential part of the pressure equalization chambers 23 are flow resistances 26, which the interior of the pressure compensation chambers 23 in the direction on the middle part 24. These flow resistances 26 can be made of ceramic materials and in the form of the in FIG. 8 nozzle plates shown. The task of these flow resistances 26 consists in distributing the gas flow in a controlled manner over the debris located in the molding box 2 that this approximately is heated evenly. To achieve this goal, once in the middle of the Mold box 2 for the flow resistances 26 opposite this area with uniform flow cross-sections of the same size are required. In the direction on the edge of the molding box 2, however, the heat dissipation from the gas increases through the molding box walls at. so that a higher gas throughput is required for a uniform application of heat. This higher or stronger gas throughput is achieved by correspondingly enlarging the flow cross-sections reached in the area of the shaped edges. The heat dissipation of the gases in the area of the molding box corners is even greater. As Fig. 8 clearly can be seen, the flow cross-sections of the flow resistances 26 in the area of the molding box corners very large compared to the cross-sections in the middle of the molding box.

It has already been mentioned that the highly heated gas by the control of the flaps 25 for a short time and controlled in opposite rubbings

1 = alternating through the pile in the molding box 2 is blown through.

The F i g. 9 shows a temperature diagram in which the temperature profile within the debris in the molding box during heating while

ao rend of the individual flow processes applied is. In FIG. 9, the lower L'nie 27 means the bottom surface of the molding box 2 and the line 28 the Lid surface. The straight line 29 running from the line 27 to the line 28 shows the inlet temperature of the Granulate. The temperature in the diagram according to FIG. 9 is in the direction of arrow 30 in degrees Celsius applied. In the first according to the diagram in FIG. 9 from bottom to top Blowing through the pile with highly heated gas shows a curve 31 that the heating of the Debris on the lid surface of the molding box is relatively low and on the sole surface is relatively high is. After reversing the direction of flow of the gas, the temperature changes accordingly a curve 32 It is in F i g. 9 recognizable that the curve 32 mi 'the curve 31 intersects.

F.s a certain leveling occurs due to the repeated reversals of the direction of flow of the gas the extreme temperatures at the boundary surfaces of the pile. The direction of arrow 30 successive temperature! · -ν rven in Fig. 9 show that their curvatures are gradually weaker and weaker, until finally one essentially Temperature line 33 running parallel to line 29 is reached, which is the balanced end temperature of the expanded clay body. At a lower temperature, if the right size, the granules are is present, the outer surfaces of the granules evenly down to a certain layer depth on one

heated state capable of ceramic bfaid (see Fig. 10). and ceramic bonding bridges 34 are formed on the contact surfaces, on which the individual Granules 35 are fused together. As a result of the prevailing temperatures, the start high The heated outer surfaces of the granules are also expanded afterwards, so that the bonding bridges 34 in a cross-section be enlarged.

If the molding boxes 2 were pulled out of the flow chamber 4 in this process then, depending on further treatment, a further enlargement of the ceramic bonding bridges 3 ' may be achieved by the post-expansion process and still by further heating. De The inflation process can be continued until the structure of the inflatable body shown in FIG. 1 is reached In this case, all the gaps 36 previously lying between the granulate 3 are covered by the inflated and now roughly cube-shaped or cuboid-shaped Gn

r.alat filled out. Through appropriate heat treatment can be any between the representation in Fig. 10 and the representation in Fig. II Bring about the state of filling of the void spaces 36,

In order to be able to carry out the method as economically as possible, a burner is provided according to FIG. 12 22 several, preferably three, flow-through chambers 4 have been assigned. For a system with several Durchströmkammera 4 can also För- ίο be arranged so that the molding boxes 2 in the sense of an assembly line process by the individual Throughflow chambers 4 are conveyed through.

According to FIG. 14, however, several throughflow chambers can also be used 4 be combined and have a * 5 common middle part 24 a. The fault lines 14 indicate that more than the three illustrated through-flow chambers 4 are also provided could be. In this way, a very large central part 24 α (FIG. 15) can be created which is used for recording large-format forms 2a is suitable. Such a design of the device is more advantageous as a device with a single larger through-flow chamber 4, because in this way the Gas routing and uniformity of heating, even with large-format expanded clay bodies, more precisely controls.

15 shows in a particularly clear manner how several throughflow chambers 4 are fluidically are combined one behind the other and have a common central part 24a, through which a conveyor track for molding boxes 2 extends. The arrows in Fig. 15 indicate the flow path of the gas. Further arrows show the conveying direction of the molding boxes 2. In FIG on the molding boxes 2 of FIG. 9 corresponding temperature curves are plotted.

In order to control the individual temperatures to the desired extent, the individual, one after the other arranged throughflow chambers 4 from the burner 22, not shown in Fig. 15, from highly heated Gas can also be supplied directly in a certain ratio.

In Fig. 15 it is also indicated how the filling state the molding boxes 2 changes if only predried, d. H. unexpanded granules run out will. Because of the great expandability of such granules, the molding boxes 2 are only up to filled to a filling line 37.

During the supply of heat, with proper control, it is finally achieved that the molding boxes due to the onset of expansion shortly before entering the last through-flow chamber 4 almost to the upper one Edge or approximately up to a line 38 in FIG. 15, but when leaving this through-flow chamber up to to the lid are filled and when re-inflating the granulate fills the gaps 36 (FIG. 10).

Claims (24)

Claims: 60 1. Method for producing bodies from expanded clay or the like, in which approximately spherical Expandable granules by heating on the surfaces in a state capable of ceramic bonding transferred to the at least partial filling of the gaps between the granules be deformed and bound to form a one-piece body, characterized in that the expandable granules (35) before approximately uniform size, either directly to a manufacturing device or to a storage container are removed, first introduced as debris in a molding box (2) and then the pile of highly heated gas alternately from the opposite side controlled, briefly until reaching at least essentially the same ceramic condition of the surface of all granulates capable of binding until the onset of the swelling process « is blown through and relentlessly supported, whereby the expandable granules in the free Expand the gaps (36) and combine them to form a body of ceramic-bonded granules will. 2. The method according to claim I _7, characterized in that the pile of pre-dried granules (35) is formed. 3. The method according to claim 1, characterized in that the pile of pre-expanded Granules (35) is formed. 4. The method according to any one of claims 1 to 3, characterized in that the ceramic bonded Expanded clay body (10) mechanically smoothed on at least one surface or with a Pattern is provided. 5. The method according to any one of claims 1 to 4, characterized in that the ceramic bonded Expanded clay body (10) on at least one surface with a surface material, for example a gaseous mass, which is then coated by the heat inherent in the body and / or is baked or sintered by a subsequent heat treatment. 6. Device for producing bodies from expanded clay od. Like. According to the method one of claims 1 to 3, characterized in that a through-flow chamber (4) for Guiding of gas heated to a high level in a burner (22) and for taking up the gas with this heating pile is provided, the pile in a movable molding box (2) with solid side walls (8) and sieve-like perforated bottom (20) and one optionally Openwork that can be used in the flow chamber or one outside the flow chamber usable solid cover (5) is included. 7. Apparatus according to claim 6, characterized in that the flow chamber (4) a central part (24) provided for receiving the molding box (2) and two on the top of the mold or the underside of the mold has subsequent pressure compensation chambers (23) which are controlled, for example by means of control flaps (25), under circular return of the heated gas to the burner with the gas outlet opening of the burner (22) and / or can be connected to the surrounding atmosphere. 8. Apparatus according to claim 7, characterized in that the pressure compensation chambers (23) have a cross section corresponding to the molding box in the area of the central part (24) and are conically tapered away from the central part. 9. Apparatus according to claim 7 or 8, characterized in that between the pressure equalization chambers (23) and the middle part (24) in each case a flow resistor (26) is arranged to divert the heated gas over the surface of the To distribute the molding box (2) or the heap in this. 10. Apparatus according to claim 9, characterized in that the flow resistances (26) except in the edge and corner areas 'have uniform flow cross-sections' and that the flow cross-sections of the areas opposite the molding box edges larger than normal, the flow cross-sections of the areas opposite the molding box corners are larger than in the edge areas to ensure even heat transfer to achieve on the pile. 11. Apparatus according to claim 9 or 10, characterized characterized in that the flow resistances (26) are designed as preferably ceramic "nozzle plates". 12. Device according to one of claims 9 to 11, characterized in that the flow resistances (26) are formed from clay granules. 13. Device according to one of claims (S to 12, characterized in that the burner (22) is equipped with a heat exchanger and that the heat exchanger, the two Pressure equalization chambers (23) and the central part of the flow-through chamber have a circular flow Enable a flow path for an oxygen-free, at least low-oxygen, highly heated gas, a fan or the like for circulating the gas is switched on in the flow path. 14. Device for producing bodies from expanded clay od. Like. According to the method one of claims 1 to 3, characterized in that several throughflow chambers (4) each with two pressure compensation chambers (23) and a central part (24) in between arranged parallel to each other and controllably connectable to a common burner (22) are. 15. Device for producing bodies from expanded clay od. Like. According to the method one of claims 1 to 3, characterized in that several throughflow chambers (4) are arranged one behind the other in a common flow path. 16. The device according to claim 15, characterized in that that each through-flow chamber (4) apart from the connection with the adjacent flow-through chambers, which is required for the one behind the other has an additional controllable connection with the burner (22). 17. The device according to claim 14, characterized in that that all flow chambers (4) arranged in parallel have a common central part (24 ″). 18. The device according to claim 17, characterized in that the common central part (24 a) of the parallel flow chambers (4) is designed in its dimensions for the simultaneous reception of several small molding boxes or the dimensions of a single large molding box (2). 19. Device according to one of claims 14 to 18, characterized in that each through-flow chamber (4) has control flaps (25) to control the flow direction of the highly heated gas to be able to reverse in a controlled manner at short notice. 20. The device according to claim 15, characterized in that when several flow-through chambers (Λ) are arranged one behind the other, they run through these conveyors and the direction of flow of the gas from one flow-through chamber to the next and the conveying direction of the conveyor are opposite to one another. 21. Device according to claim 19, characterized in that that a partially designed as a roller conveyor (11) conveyor for molding boxes (2) or for expanded clay bodies (10), starting from a filling station (1), through one or more Through-flow chambers (4). a demolding station (6) and at least one post-treatment station runs. 22. The device according to claim 21, characterized in that for aftertreatment of the expanded clay body a heated pair of smoothing rollers (12) is provided. 23. The device according to claim 21, characterized in that that for post-treatment of the expanded clay body (10) at least one heated embossing picsse (13) is provided. 24. Device according to one of claims 6 to 23, characterized in that all metal surfaces, those with granules or the expanded clay bodies (10) formed therefrom be: temperatures come into contact above 500 ° C, with a separating compound of preferably higher melting point Matcriai as the clay of the granules or expanded clay bodies are coated. In addition 7 sheets of drawings