DE2155933A1 - DEVICE FOR MANUFACTURING FIRED MOLDED BODIES FROM GRANULES OF BLAEHTON OR THE LIKE - Google Patents

Description

PATENT LAWYERS

DIPL.-PHYS. DR. J. FRICKE DR.-ING. R. DOERING

BRAUNSCHWEIG MUNICH

Zytan Dolle Society for Thermochemical Process Engineering

mbH & Co. KG _x 33 Braunschweig, Porschestr. 10

"Device for the production of fired moldings from Granules of expanded clay or the like. "

The invention relates to a device for producing fired molded bodies from granules of expanded clay or the like., consisting of a preferably double frustoconical combustion chamber with a holder for the fuel receiving combustion box in the plane of the largest chamber cross-section and from one to the two narrow ends of the Combustion chamber connecting pipe system for the circle? running heating and reaction gases, in which at least one open burner device, a circulation device and if necessary a switching device to reverse the flow direction are provided by the combustion chamber.

Auo dot * Deubachen From Legeschrif'fc 1 9l'l 372 are a process and EjLae device for making fired ones i'Oniiktfr'purn known. DoL of this known device iab

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provided a double-frustoconical flow housing for the highly heated by a burner combustion gases and for receiving the movable molding boxes, in which the granules made of combustible material is added. The movable molding box consists of solid side walls and a sieve-like perforated bottom as well as a cover which is either perforated like a sieve when used in the flow-through chamber or is solid when used outside the flow-through chamber. The two frustoconical chamber sections of the flow-through chamber serve to equalize the pressure and are connected to a line system in which the gases, which are highly heated by the burner, can be circulated. For better distribution of the combustion gases over the entire combustion cross-section in the combustion chamber, flow resistances are arranged on both sides of the plane of the largest cross-section, which the supplied combustion gas expands over the entire surface area of the granules located in the combustion chamber.

In the devices in question, the heating gas serves on the one hand as a heat carrier for heating the material to be fired, on the other hand as a chemical agent to influence the expansion behavior of the granules and to control the processes in the ceramic bond that occurs after the expansion of the granules. In the ¹ known device, the heating gases are alternately from the opposite flat sides de *.

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- 3 combustion box fed to the granulate in order to ensure that the

moderate influence of the heating gases on the granules both during expansion and during ceramic bonding to achieve and thus ceramically bonded moldings of continuous to obtain a fine, even cell structure.

In the method that can be carried out with the known device, the influencing variables, such as the temperature, which is in the range from 1000 to 1200 ^° C., and the duration of the exposure time and the speed and composition of the heating and reaction gases, can be determined according to the initial properties of the raw materials used as well as according to the required mechanical and physical properties of the finished molding vary within relatively narrow limits. However, these possibilities of variation are limited in the known device, since it is extremely difficult to subject all the granules of a filling of a combustion box to the same treatment by the gases. In particular, considerable problems arise in the vicinity of the floor and the walls of the combustion box. These problems arise from the fact that the walls and the bottom of the combustion box are exposed to the action of the heating and reaction gases on the one hand, and to interaction with the heated material to be fired on the other. Due to the high temperatures in the combustion chamber, the choice of materials used for the combustion box is considerably restricted, especially since in the known method the materials of the combustion box are exposed to considerable temperature fluctuations, which

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falsification and destruction of the firing boxes, making them unusable have as a consequence. Furthermore, when certain temperatures are exceeded, a kind of chemical affinity occurs the granules and the materials of the molding boxes, which then, when both materials have approximately the same temperature values assume to a kind of wetting of the molded parts adjoining the granules and thus to chemical bonds between the various materials and materials. The resulting firm adhesion between the material to be fired and the firing box "Impairs the proper demolding of the molding and at the same time leads to the destruction of the parts of the molding box.

In addition, it is extremely difficult to precisely determine the temperature and chemical composition of the heating gases set to the desired values and in the course of the process according to a predetermined repeatable regularity can be changed quickly and reliably.

It is the object of the invention to develop the device described in more detail at the beginning so that the difficulties outlined are overcome and fired molded bodies of the type in question can be produced with the device, which are characterized by a high degree of uniformity of their properties over the entire cross-sectional extent and can be reproducibly generated in continuous process reliably in the desired ^quality.

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- 5 - This object is achieved according to the invention in that with

1 ι

one that maintains the required pressure in the pipe system Fan or the like. Directly in series, the two chambers connected to one another via a constriction continuously working and operated with circulating storage mass regenerator are arranged and the Combustion chamber connected to the regenerator with its two ends on both sides of the constriction in the shunt is. A cooling device is advantageously switched into the main gas circuit in series with the fan, by adjusting the temperature if a reduction is required the fuel gas temperature is reached.

In this way, the heating and reaction gases are circulated get a system which allows to work continuously and economically from the Heat dissipated from the combustion chamber in the gases returned to the combustion chamber, whereby it is carried out through the main circuit the amount of gas supplied to the bypass circuit and thus to the combustion chamber, its speed and its temperature can be controlled precisely and changed to the desired extent.

It is advantageous if a deduster for the gas, for example a cyclone, is arranged in series with the fan, so that

the storage mass remains free of dust deposits and a ' Filling of the gap spaces with dust is prevented. The connection end expediently has at least the inflow

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side of the combustion chamber one from the holder for the

Combustion box widening away chamber in which the burner device is arranged in a concealed manner opposite the combustion chamber. With this burner arrangement there is no transmission of radiant energy the inevitable energy losses within the in balanced in a closed circuit of circulating fuel gas. At the same time, with the help of the burner, the Temperature of the gases in the inflow on the combustion box: quickly and sensitively control borrowed gases and change themselves through changes the burner setting can also result in a corresponding change in the chemical composition of the fuel gases. :

Through the main circuit and the shunt circuit for the Brennc-se results in a separate, different in temperature adjustable flow. The arrangement of the

i chamber and regenerator with all accessories existing unit can also be used continuously without changing the direction of the flow work.

Another essential feature for the development of the invention is the fact that the receptacle in the plane of the largest cross section of the combustion chamber has an annular pocket open towards the axis of the chamber for guiding and covering the combustion box edge against the combustion gases. The pocket is expediently designed so that it cooperates in a sealing manner with the edge of the combustion chamber, so that the two are in

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Direction of chamber sections widening the largest cross-section the combustion chamber are sealed against each other and the heating and reaction gases are completely contained in the combustion box Granulate mass must flow through.

The combustion chamber can also be used as a chamber with over the essential Part of its height is formed with a constant cross-section be, to the initially serving as a diffuser or collector cross-section tapering sections and here the widening

Connect chamber sections for the supply and discharge of the gases.

It is of particular practical importance when the pocket is in contact with the edge of the combustion box for the discharge of Has heat serving heat conducting surfaces. The heat dissipation surfaces are expedient for precise control of the dissipation of heat connected to a forced cooling system.

Expediently in the described design of the combustion chamber Combustion box to be used has, according to a further feature of the invention, an annular one outer support frame, which was added to the guide pocket and the one with the box filling, i.e. the. Firing material in the form of the granulate mass limiting the heat transfer: Elements is related.

The arrangement is desirably made such that the '■ filling chamber of the internal box is limited by a heat shield,

»■

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the webs that limit the heat flow on the support frame

is supported. This is how the burning boxes are designed possible, the heat flow from the areas of the fuel near the edge to decelerate so far that these areas are exposed to practically the same treatment by the heating gases as the areas remote from the edges of the granulate mass. This ensures an extremely good homogeneity of the Consistency and properties of the Pormkörper achieved over the entire cross-section. On the other hand, one can

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• Achieve controlled heat flow from the heat shield that the heat shield always remains at a temperature of 20 to 60 ° below the temperature of the granules, which temperature difference is sufficient to exclude a chemical reaction between the material to be fired and the material of the heat shield, so that the burning box a has a long service life and easy removal of the fired Pormkörper from the firing box is guaranteed. The long service life of the fuel box can be further enhanced by the fact that the heat shield from a multiplicity W consists plurality of individual heat shield panels which are each separately and suitably easily supported replaceably on the support frame and arranged so as to form joints between them, so that Warps or deformations of the molding box due to the action of heat or alternating temperatures are not to be feared, especially since the holding frame itself is protected on the one hand against the direct action of the combustion gases, on the other hand is largely insulated from the heat shield and finally by the

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Walls of the pocket is subjected to controlled cooling.

This ensures that the heat shield assumes a temperature of 20 to 60 ° C below the product temperature, during the Support frame can be kept at a temperature of the goods from 1000 to 1200 C at a temperature of about 400 °.

The permeable bottom of the burning boxes is expediently made from a bar grate, with the grate bars supported on the heat shield and as individual bars, grate elements or are provided as a unit of several rods. The rods can expediently have a raised, rectangular shape Have cross-section and are provided with cross-sectional dimensions and spaced that the ratio from the perforated surface to the entire bottom surface of the combustion box roughly equal to the relative gap space of the granular The material to be fired. In practice, there is a ratio of the perforated area to the total floor area between about 0.26 and 0.46, preferably between about 0.36 and 0.40, has proven advantageous. The temperature of the grate is kept at values that correspond to the temperature of the heat shield.

The invention is explained below with reference to schematic drawings explained in more detail using an exemplary embodiment.

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The Pig. la, Ib and lc show the main parts of the device according to the invention, partly in vertical section, partly in side view.

Fig. 2 is a section through the edge area on an enlarged scale a combustion box according to the invention.

Fig. 3 shows in detail the edge area according to FIG. 2 in Top view.

4 and 5 are representations according to FIGS. 2 and 3 of a different design.

According to Fig. La to Ic, the device consists of a Combustion chamber 1 and a regenerator 2, the regenerator in a main circuit 3 for circulating fuel gases and the combustion chamber 1 in a bypass circuit 4 for the combustion gases are arranged, which shunt circuit to the regenerative

tor is connected.

The combustion chamber 1 consists of two in opposite Rich-P device tapering chamber sections 5 and 6, through which the combustion chamber regions 7 and 8 are formed. On level 9 of the common largest cross-section of the combustion chamber

! a holder for a combustion box 13 is arranged. The shark

tion consists of an outside of the cross-section of the

J ring-shaped pocket 12 lying on the combustion chamber, which is open towards the axis of the combustion chamber and has guide surfaces 10, which cooperate with the edge region 14 of the combustion box 13 in the manner to be described below. The leadership

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surfaces 10 of the annular pocket 12 are shown in FIG

Example connected to a cooling system 11, through which the temperature of the Pührungsflächen 10 to a predetermined Can be set.

At the narrow end of the upper chamber 7 there is a further chamber 19, the cross section of which extends in the direction of the plane 9 expanded. A line 23, which belongs to the shunt circuit 4, is connected to the chamber 19. Furthermore is in this Chamber a burner arrangement 21 arranged so that on the one hand the combustion gases generated by the open burner are reliable mix with the gases supplied through the line 23, on the other hand the material to be fired itself from a radiation the open burner flames is protected.

Since the arrangement described can also be operated in the known manner mentioned at the outset, in which the fuel gases also has the largest cross-section of the combustion chamber alternately fed from one side and from the other the narrow end of the lower combustion chamber section 8 has a widening chamber 18, 20 to which the line 24 the shunt circuit 4 and a burner device 22 attached; are closed.

The two lines 23,24 may be connected to alternate operation mentioned a Ums ehalteinrich- j tung 25 to the regenerator 2 of the shunt circuit for j. j

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- 12 -

The shown regenerator works continuously and is with

a flowable and constantly circulating heat storage lake, which is indicated at 50. This storage mass is withdrawn from the regenerator through a corresponding lock at 3 ^ and discharged in the direction of arrow 51, and fed to an elevator 36, which feeds the storage mass to an inlet 35 provided with a corresponding lock at the upper end of the regenerator.

The regenerator has a strong constriction about halfway up 33, through which an upper regenerator chamber 31 with a corresponding lower regenerator chamber 32 in connection stands. The constriction is dimensioned so that the storage mass has essentially no resistance worth mentioning pass from the upper chamber 31 into the lower chamber 32 can, while the passage of the gases through the constriction 33 is greatly restricted.

The regenerator 2 has a connection piece at the upper end 43 for the removal of the fuel gases and at the lower end a feed nozzle 38 for the return of the fuel gases, the feed a corresponding grid floor leading the storage mass is assigned. Through the connections described the regenerator is switched on in the main circuit 3 for the fuel gases; This main circle shows in series with the regenerator a fan 4l, which for the required pressure in Circulatory system. Furthermore, in the main circle there can be one

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Cooling device 42 may be provided to prevent any overheating balance. In addition, the main circuit has a dust extractor in the form of a cyclone 72, so that a continuous discharge of the dust carried along by the heating and reaction gas ■ takes place. \

The shunt circuit 4 is via the connections 28 and 30 and the lines 26 and 27 are connected to the main circuit 3 via the regenerator 2, the two connections each being directly lie above or below the constriction 33 of the regenerator. The connections can still be ring-shaped Be assigned to distributor sections 28a and 30a.

In the main circuit 3, the gases always flow in the direction indicated by the arrows, in the shunt circuit 4 behind the switching device 25, the direction of flow shown by the arrows can be reversed with the aid of the switching device will.

In the example shown, the combustion gases are discharged from the combustion chamber 1 via line 24, switching device 25 and the line 27 is fed to the connection 30 lying above the constriction 33 and meet there the cooler storage mass, which is ready to absorb the heat in the gases. The gases, which continue to cool down, are at 43

derived from the regenerator chamber 31, possibly cooled at 42 j

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as well as dedusted in the cyclone 72 and with. the desired pressure is pressed into the regenerator chamber 32 via the blower 41. In this chamber is the storage mass heated by the returned fuel gases, which is now the cooler one Heat the gases to the desired temperature. Depending on the selected flow conditions, the constriction 33, which is filled with the storage mass, a flow

_ Resistance is formed, which ensures that a predetermined Amount of the heated gases at a predetermined speed at 28 in the bypass circuit 4 and passes through the line 26, the switching device 25 and the line 23 of the Chamber 19 is supplied, in which the gases under the action of the burner device shielded by the projecting wall 17 21 is suspended. This allows the temperature of the inflowing gases to be corrected sensitively and at the same time also influence the chemical composition of the inflowing gases in the desired way. The so treated heating

w and reaction gases enter the combustion chamber section 7 and meet the granulate mass in the combustion box 13 there. All gases must flow through this granulate mass if the combustion box forms a reliable seal with the walls 10 of the pocket 12.

With the aid of the fan 41, the cooling device 42 and the burner 21, the parameters of the fuel gases can be determined quickly and steer it in precisely and change it in the desired manner during the treatment of the goods. At the same time, the in that

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The heat contained in the system is largely always used again, so that the material can be treated in a very economical manner. Excess gases can be discharged via an exhaust gas connection Tk by appropriate setting, in particular when the burner devices 21, 23 are switched on.

With the measures described above, the prerequisite is created for the treatment of the granular masses, in particular the ceramic bonding of the granules in the firing boxes is carried out in a highly reproducible manner can, so that moldings with consistent properties and thus high quality can be achieved.

In order to ensure that the edge areas of the molded body during the firing process are subjected to the same treatment as the areas of the molded body remote from the edge, the combustion box is designed in a particularly expedient manner, so that in cooperation with the cooling described of the guide surfaces 10 of the receiving pockets 12 of the combustion chamber a very precise control of the temperature in the edge region of the combustion body and a desired temperature difference can be obtained between these edge areas and the immediately adjacent wall parts of the mold. .

For this purpose, the combustion box according to FIGS. 2 and 3 or Jj and 5 consists of a holding frame 60, which is expediently made of very low-alloy steel and has lower and upper guide surfaces 61 and 62, which are completely received in the pocket 12 of the combustion chamber and in one, the

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Heat transfer promoting contact with the guide surfaces of the pocket 12 are. As a result of the direct cooling of the pocket walls, the holding frame 60 can be kept at a temperature of the goods of 1000 to 1200 ° C. at about 40O ⁰ C, which means that there is no fear of warping or deformation of the holding frame due to the influence of temperature. This risk is further reduced by the fact that the holding frame 60 does not come into direct contact with the material to be fired 69, but against it. ψ is insulated over this by a predetermined heat transfer resistance.

For this purpose, the holding frame 60 is lined with a heat shield which, in the preferred exemplary embodiment shown, consists of individual thin heat shield plates 63 which are arranged with the formation of sufficiently large separating joints 63a. The heat shield plates 63 are at a considerable distance from the holding frame 60 and are supported on this by narrow webs 64 whose heat-conducting cross-section is dimensioned, if necessary, by arranging corresponding recesses 66 according to FIG Heat transfer through the webs 64 is formed. The webs are expediently fastened easily detachably to the holding frame at 65, whereby the heat transfer resistance can also be influenced by the type and arrangement of the fastening. The space between the heat shield plates 63 and the inside of the holding frame 60 is covered with a heat-resistant thermal insulation material 70

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completed in a known manner. In the arrangement according to FIGS. 4 and 5, a flow gap 73 is provided between the heat shield plates 63 and the insulation 70, which when the Form for rapid heating of the heat shield plates to a temperature about the product or 20 to 60 ° C below.

The bottom of the fire box is formed by a grate that in the example consists of individual grate bars 67, each separately by appropriate shoulder lugs 68 to the Heat shield plates 63 are supported. Instead of the individual bars, however, grate elements or a grate can also be used as a structural unit be provided.

Each grate bar 67 expediently has a long, rectangular shape Cross-section and is arranged on edge. The dimensioning of the grate bars as well as their mutual distance below Formation of the openings 71 are chosen so that the ratio of the openings to the total floor area of the combustion box is approximately corresponds to the gap space of the granular material to be fired 69. Thereby values for this ratio in the beginning indicated size proved to be particularly advantageous.

The particular embodiment of the burning boxes described also allows the burning boxes to be guided during the entire process in a circuit which includes preheating of the burning boxes, a filling station, the combustion chambers, a post-blowing station and a demolding station, in each station the

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The holding frame on the one hand and the heat shield on the other hand can each be kept at the desired temperature for the entire duration of the passage through the circuit. The rust and · heat shield are maintained at a product temperature from 1000 to 1200 ⁰ C during the ceramic bond in each case 20 to 60 ° below the temperature of the material, wherein a temperature change of rust and heat shield should be no greater than about 150 ° C. The supporting frame is held at a temperature of about 400 ⁰ C in the combustion chamber and should likewise throughout the cycle ^ if no major temperature changes experienced as about 150 ⁰ C. This results in a temperature difference between the grate or the shield and the support frame during the ceramic bonding of the goods of approx Granules close to the firing boxes are not subject to any influence that deviates from the influence of the granules located at a distance from the molded parts. This gives an extraordinarily high level of uniformity in the treatment and thus a high level of uniformity in the quality of the fired shaped bodies. Only then is it possible to take full advantage of the precise control of the temperature and chemical composition of the fuel gases and the ability to quickly change these parameters during the combustion process, since these influencing variables apply uniformly to all areas, including the areas close to the mold walls the molding can affect *

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Claims (1)

Claims Device for dividing ceramic-bonded molded bodies from granules of expanded clay or the like. Consisting of from a combustion chamber, preferably tapering in opposite directions, with a holder for a combustion box in the plane of the common largest chamber cross-section and from one to the two ends of the Combustion chamber connecting pipe system for the in the circle guided heating and reaction gases, in which at least one open burner device, a circulation device and if necessary a switching device for reversing the flow direction through the combustion chamber are provided, characterized in that with a maintaining the required pressure in the line system Fan (41) or the like. Directly in series the two via a constriction (33) connected chambers (31> 32) of a continuously operating and circulating storage mass (50) operated regenerator (2) are arranged and the combustion chamber (1) in the bypass (4) with both ends (23,24) on both sides of the constriction (33) to the Regenerator (2) is connected. 3 0?, R 2 1/0 3 9 6 -.20 - 2. Device according to claim 1, characterized draws that in series with the fan (41) one Cooling device (42) switched on in the main gas circuit (3) is. 3. Apparatus according to claim 1 or 2, characterized in that in series with the fan (41) a dust extractor for the gas, for example a cyclone ψ is arranged. 4. Apparatus according to claim 1 to 3, characterized in that the connecting end (17) at least the inflow side (23) of the combustion chamber (1) one away from the holder (12) for the combustion box (13) widening chamber (19), in which the burner device is concealed in relation to the adjacent combustion chamber section (7) (21) is arranged. ^, Device according to claim 1 to 4, characterized gekennzei chnet that the changeover device (25) is arranged in the shunt circuit (4) between the regenerator (2) and the combustion chamber (1). ^ Device according to claim 1 to 5, characterized in that the receptacle (12) in the Level (9) of the largest cross section of the combustion chamber (1) a 3 0 2 8 2 1/0396 to the axis of the chamber open to the annular pocket (12) Guide and cover the edge of the combustion box opposite the
Has heating and reaction gases. j 7. Apparatus according to claim 6, characterized! marked that the pocket (12) with the ί Combustion box edge (-14) cooperates in a sealing manner. | 8. Apparatus according to claim 7, characterized - \ indicates that the pocket (12) with the
Combustion box edge (H) has contacting heat dissipation surfaces (10). 9. Apparatus according to claim 8 ^ thereby skillfully shows that the heat dissipation surfaces (10) of the | : Bag (12) are connected to a cooling system (11). j ί10. Device according to claim 6 to 9, characterized in that; ! characterized in that the combustion box (13) j ί has an annular outer support frame (60) which i is picked up by the guide pocket (12) and with the ■ ! I. Firing material filling (69) limiting the heat transfer | .. elements (64) is connected. ί 11. The device according to claim 10, characterized characterized that the filling space of the combustion 309821/0396 box (13) is limited by a heat shield (63), the is supported on the support frame (60) via webs (64) which limit the heat flow. 12. The device according to claim 11, characterized in that that the heat shield (63) consists of a multiplicity of individual, with the formation of parting lines (63a) arranged and thin visual shield supported individually on the holding frame (60) ^w plates consists. 13 · Device according to claim 11 or 12, characterized in that the space between the heat shield (63) and the inside of the holding frame (60) is filled with a heat insulating material (70). 14. The apparatus of claim 11 to 13, characterized in that the bottom of the combustion box i chne t w consists of grate bars (67) supported on the heat shield (63), which are provided as single bars, grate elements or a unit made up of several bars. 15. The device according to claim 14, characterized in that that the grate bars (67) are designed and arranged so that the ratio of perforated area to the entire bottom surface of the firing box corresponds roughly to the relative gap space of the firing material filling. 309821/0396 21B5933 16. The device according to claim 15, characterized in that that the ratio of perforated area to total floor area is between about 0.26 and 0.Ί6, preferably is between 0.36 and 0.40. 982 1/0396