EP3303962A1

EP3303962A1 - Suspended brick for a suspended roof of a tunnel furnace, suspended roof having such suspended bricks and resting bricks, tunnel furnace having such a suspended roof, and use of a fireproof brick

Info

Publication number: EP3303962A1
Application number: EP16724615.6A
Authority: EP
Inventors: Uwe Schuhmacher; Jörn Böke; Rolf-Dieter KIZIO
Original assignee: Refratechnik Holding GmbH
Current assignee: Refratechnik Holding GmbH
Priority date: 2015-05-29
Filing date: 2016-05-17
Publication date: 2018-04-11
Anticipated expiration: 2036-05-17
Also published as: PL3303962T3; EP3303962B1; EP3303962B8; DE102015006995A1; WO2016192981A1; ES2790724T3

Abstract

The invention relates to a suspended brick (5) for a suspended roof of a tunnel furnace (1) for the ceramic industry, preferably the coarse ceramic industry, in particular for brickworks, to a suspended roof (5) having such suspended bricks (9) and having resting bricks (11), to a tunnel furnace (1) having such a suspended roof (5), and to the use of a fireproof brick.

Description

Hanging stone for a suspended ceiling of a tunnel kiln, suspended ceiling with such suspended stones and semi-trailers, and tunnel kiln with such a suspended ceiling and use of a refractory stone

The present invention relates to a suspension rock for a suspended ceiling of a tunnel kiln for the ceramic, preferably heavy clay, industry, in particular for brickwork, a suspended ceiling with such suspension rocks and with Aufliegersteinen and a tunnel kiln with such a suspended ceiling and the use of a refractory brick.

From DE 1 925 953, for example, a tunnel furnace for burning ceramic bodies is known, which consists of a fixed tunnel-like furnace shaft and several kiln cars, which are moved through the kiln shaft on rails. The furnace shaft has two side walls and a flat suspended ceiling. The suspended ceiling has a plurality of hanging stones, which are fastened by means of suspension brackets each to a ceiling support which extends from one to the other side wall. The hanging stones each consist of two mutually walled shaped tiles. The side walls have at their upper end in each case a connecting beam on which rest the ceiling support. The joists are made of brick chippings or chamotte with blast furnace or alumina cement.

Besides, tunnel kilns from Hans Lingl Anlagenbau and Verfahrenstechnik GmbH & Co. KG are known. These tunnel kilns for the heavy clay industry have a flat suspended ceiling with hanging bricks and hard-grass paving stones.

The problem with the known tunnel ovens is the wear ß the suspended ceilings, especially the hanging rocks and the semitrailer stones, due to alkali attack. Fireclay bricks usually consist of corundum, mullite, cristobalite etc. and amorphous phases. Critical is the formation of feldspar representatives (such as leucite, casilite, etc.) and sodium salts, which in Si0 ₂ - undersaturated, alkali-rich melt may arise. Since the feldspar representatives occupy a larger volume than mullite, this ultimately leads to cracks and flaking ("alkali bursting").

In particular, in areas of the so-called "alkali belt" (eg Spain, North Africa, Middle East to Saudi Arabia, Iraq, Iran), clays are used with elevated alkali parts for the production of bricks.The wear ß the hanging stones is not dangerous because it lead to it can, on the one hand, break apart the hanging stones and at least partially fall off, and on the other hand, stones falling on the suspension stones also fall down be repaired.

The object of the present invention is to provide a suspension rock for a suspended ceiling of a tunnel kiln for the ceramic, in particular coarse ceramic, industry, which ensures a longer service life of the tunnel kiln.

Other objects are the provision of a suspended ceiling with such hanging stones and with Aufliegersteinen and the provision of a tunnel kiln with such a suspended ceiling.

These objects are achieved by a hanging stone having the features of claim 1, a suspended ceiling having the features of claim 4 and a tunnel kiln having the features of claim 1-4. Advantageous developments of the invention are characterized in the subsequent subclaims.

In the following the invention will be explained in more detail by way of example with reference to a drawing. Show it : Figure 1: Schematically a perspective view of a portion of a furnace tunnel of a tunnel kiln according to the invention without kiln cars

Figure 2: Schematically a vertical section of a suspension rock according to the invention

Figure 3: Schematically a perpendicular to a tunnel width direction vertical section of two hanging stones with Aufliegerstein and insulation layer

Figure 4: Schematically a vertical to a tunnel longitudinal direction vertical section through a portion of the suspended ceiling according to the invention without suspension brackets and ceiling beams

Figure 5: Schematically a perspective view of a portion of a

Furnace tunnels of a tunnel kiln according to the invention without kiln cars and without tunnel side walls with semitrailer stones according to another embodiment

The tunnel kiln 1 according to the invention has an oven tunnel 2 and a plurality of kiln cars (not shown) for transporting the kiln, in particular the bricks, through the kiln tunnel 2.

The furnace tunnel 2 has two tunnel side walls 3, a tunnel foundation plate and the suspended ceiling 5 according to the invention. On the tunnelfundamentamentplatte rails are arranged in a conventional manner, on which kiln carts (not shown) pass through with the kiln tunnel 2 disposed thereon.

The two tunnel side walls 3, the upper side of the kiln cars and the suspended ceiling 5 delimit a fuel channel 6. The kiln tunnel 2 also has a horizontal tunnel longitudinal direction 7a, a horizontal tunnel width direction 7b perpendicular thereto, and a vertical tunnel height direction 7c. The two, preferably vertical, tunnel side walls 3 are arranged spaced apart in the tunnel width direction 7b. In addition, the two tunnel side walls 3 each have a Wandau ßenseite 3 a, a wall inner side 3 b and an upper, preferably horizontal, wall end surface or wall top edge 3 c.

The suspended ceiling 5 according to the invention comprises a plurality of ceiling beams 8, a plurality of hanging rocks 9, hanging brackets 1 0 for suspending the hanging rocks 9 on the ceiling beams 8, resting on the suspension rocks 9 Aufliegersteine or intermediate stones 1 1 and a plurality of arranged on the semitrailer stones or intermediate blocks 1 1 insulation layers 1 2 on.

The elongate ceiling beams 8 each extend parallel to the tunnel width direction 7b from one side wall 3 to the other side wall 3. Thus, they span the combustion channel 6 in the tunnel width direction 7b. They are preferably on the wall end faces 3c. In addition, the ceiling beams 8 are arranged next to one another as seen in the tunnel longitudinal direction 7a. Alternatively, the ceiling beams 8 may be e.g. be arranged on an independent of the side walls 3 steel structure.

Preferably, the ceiling beams 8 are each double T-beam or I-beam. In this case, the ceiling beams 8 preferably each have a central, vertical web wall 1 3 and an upper and a lower, plate-shaped flange 1 4, 1 5 on. The two flanges 1 4; 1 5 each have a flange inner side 14 a; 1 5a facing the other flange 1 4; and a flange face 1 4b; 1 5b facing away from the other flange 1 4; With the flange outside ßenseite 1 5b, the lower flanges 15 are on the wall face 3 c and the steel structure. The ceiling beams 8, in particular the double-T beams or I beams, are preferably made of steel.

In the context of the invention, it has now been found that it is particularly advantageous if the fired hanging stones 9 and the semi-trailer stones 1 1 because of certain basic refractory material with direct ceramic bond.

Refractory products are according to DIN 51 060: 2000-06 non-metallic, ceramic materials, which have a fire resistance, ie a cone drop point (temperature) of> 1 500 ° C. According to DIN EN ISO 1 0081: 2005-05, a distinction is made between non-basic and basic refractory products based on the chemical reaction behavior. The group of non-basic products comprises the materials of the Si0 ₂ -Al ₂ 0 ₃ series and other materials which are not grouped according to their chemical reaction behavior, such as SiC and carbon products. The high Si0 ₂ - containing materials are referred to as acidic. An essential feature of most basic products is that the sum of the oxides MgO and CaO outweighs. In addition, chromite, picrochromite, spinel, and forsterite rocks are expected to be basic products, although they are nearly neutral.

According to the invention, the suspended rocks 9 and semi-trailers 11 are magnesia (M) or magnesia-chromite (MCr) or magnesia-zirconia (MZ) according to DIN EN ISO 1 0081 -2: 2005-05. Preferably, the hanging rocks 9 and 1 1 Aufliegersteinen each to Magnesiasteine at least the group M 90 according to DIN EN ISO 1 0081 -2: 2005-05. If the suspended rocks 9 and semi-skirts 11 are magnesia-chromite stones, these are preferably rocks of at least the group MCr 70 according to DIN EN ISO 1 0081 -2: 2005-05. In this case, the hanging stones 9 and semi-trailers 1 1 preferably all consist of the same material. But they can also consist of different materials.

The hanging stones 9 according to the invention are produced in a manner known per se from an offset which comprises a basic mixture of raw materials and a temporary binder, preferably lignosulfonate or organic acid. ren, such. As apple or citric acid, or starch or mixtures of the aforementioned binders contains. According to the invention, the offset contains binding acetone proportions (based on the dry mass of the offset) <5% by weight, preferably <1.5% by weight, more preferably no binding clay. The offset is pressed under high pressure. During firing, the binder volatilizes and forms the direct ceramic bond.

The structure of the hanging stones 9 and the semitrailer stones 1 1 will now be discussed in more detail below:

The hanging stones 9 each have a first stone width direction 9a, a second stone width direction 9b perpendicular thereto and a stone height direction 9c perpendicular to the first and second stone width direction 9a;

In addition, the hanging stones 9 each have four pairwise opposite, first and second stone side surfaces 16a, b and two stone end surfaces 16c. In this case, the two first stone side surfaces 16a face each other in the first stone width direction 9a and the second stone side surfaces 16b face each other in the second stone width direction 9b. The stone end faces 1 6c face each other in the rock height direction 9c.

The hanging stones 9 are preferably in the form of double T-beams or I-beams formed (Fig. 1 -3). Respectively. the hanging stones 9 have the shape of a double-Ts or Ts in a section perpendicular to the second stone width direction 9b (FIGS. 2, 3). As a result, the hanging stones 9 each have a, in particular cuboidal, central web or center beam 1 7, at one end of the beam, two, in particular cuboid, hangers 1 8 connect and connect to the other end of the beam two, in particular cuboidal, Auflagerleisten 1 9. The middle beam 1 7 and the strips 1 8, 1 9 are integrally formed. Thus, the hanging stones 9 according to the invention are monolithic or integrally formed. The middle beams 1 7 are in particular of cuboid shape and have four pairwise opposite first and second, preferably planar, beam side surfaces 1 7a, b and two beam end surfaces 1 7c. In this case, the first beam side surfaces 1 7a face in the first rock width direction 9a, and the second beam side surfaces 17b face each other in the second rock width direction 9b. The beam end faces 1 7c face in the rock height direction 9c and are preferably perpendicular to the rock height direction 9c.

The hangers 1 8 and the Auflagerleisten 1 9 are also preferably each cuboid. The two suspension rails 1 8 and the two Auflagerleisten 1 9 close in each case to one of the two second beam side surfaces 1 7b and stand from this. In addition, the two suspension rails are 1 8 in the second Steinbreitenrichtung 9b opposite. And the two Auflagerleisten 1 9 are also in the second Steinbreitenrichtung 9b opposite. The two suspension rails 1 8 and the two Auflagerleisten 1 9 thus each in opposite directions from the central beam 1 7 from. In each case, a suspension bar 1 8 of a support bar 1 9 in Steinhöhenrichtung 9c opposite.

The two suspension rails 1 8 and the support strips 1 9 each have a strip inner surface 1 8a, 1 9a one of these opposite Leistenau ßenfläche 1 8b, 1 9b and a strip side surface 1 8c; 1 9c and two last end faces 1 8d; The strip inner surfaces 1 8a, 1 9a face each other. The Leistenau ßenflächen 1 8b, 1 9b preferably terminate flush with the respective beam end face 1 7c and form the planar stone face 1 6c. The strip end faces 1 8d, 1 9d preferably each terminate flush with the respective first bar side surface 1 7a, so that the first stone side surfaces 16a are continuous with a planar surface. The second stone side surfaces 1 6b, however, have a stepped course. As already explained, the suspended ceiling 5 also has the suspension brackets 1 0 for suspending the hanging stones 9 on the ceiling beams 8. The suspension brackets 1 0 have in a conventional manner in each case two U-shaped bracket legs 20, which are connected to each other by means of a clamp connecting web 21. The clip legs 20 each have two bent leg ends 20a, b. The suspension brackets 1 0 are preferably made of steel, preferably St 37 or higher grade steel.

In addition, the suspended ceiling 5, as also explained, a plurality of inventive burned Aufliegersteine 1 1 for receiving the insulating layer 1 2. According to a first embodiment (FIGS. 1, 3, 4), the semi-trailer blocks 1 1 are plate-shaped and parallelepiped-shaped and have two plate sides 1 1 a, b, which are vertically opposite, and four, plate edge surfaces 1, which are perpendicular to the plate broad sides 11a, b 1 c; d up.

According to a further embodiment (FIG. 5), the second plate edge surfaces 1 1 d of the semi-trailer blocks 1 1 are stepped. They taper from the second disk broadside 1 1 b to the first disk broadside 1 1 a back. In a cross section parallel to the first plate edge surfaces 1 1 c, the semitrailer stones 1 1 are formed due to its T-shaped. The second plate edge surfaces 1 1 d thus each have a stepped shoulder 4 with a first step surface 4 a parallel to the plate broad sides 11 a, b and a second step face 4b perpendicular to the plate broad sides 11a, b. The second step surface 4b adjoins the first plate broad side 1 1 a.

The assembly of the suspended ceiling 5 according to the invention and the structure of the insulating layer 1 2 will now be explained in more detail below:

The suspension brackets 1 0 are each with their upper leg ends 20 a in the ceiling beams 8, in particular the lower flanges 1 5, mounted. In addition, the hanging stones 9 are suspended with their two suspension rails 1 8 each in the suspension brackets 1 0. The lower leg ends 20b of Clamp legs 20 are located on the strip inner surfaces 1 8a of the suspension rails 1 8. The hanging stones 9 thus depend on the suspension brackets 1 0 or are suspended from this. In this case, the hanging stones 9 of a ceiling support 8, which are adjacent to one another in the tunnel width direction 7b, preferably bear against one another with their first stone side surfaces 16a. The hanging stones 9 adjacent to one another in the tunnel width direction 7b, which are suspended on the same ceiling support 8, form a horizontal hanging stone row 22 extending in the tunnel width direction 7b. Between individual hanging stones 9 adjacent to one another in the tunnel width direction 7b there is preferably an expansion joint which is filled with ceramic fibers ,

The individual horizontal hanging stone rows 22 are adjacent to each other in the tunnel longitudinal direction 7a. The support strips 1 9 of the suspension rocks 9 of the mutually adjacent hanging stone rows 22 are facing each other. Respectively. the second stone side surfaces 1 6b of the hanging stones 9 of the mutually adjacent hanging stone rows 22 face each other.

Between two in the tunnel longitudinal direction 7a mutually adjacent hanging stone rows 22, the semitrailer stones 1 1 are inserted. The Aufliegersteine 1 1 are each on the strip inner surfaces 1 9a of Auflagerleisten 1 9. The Aufliegersteine 1 1 of the first embodiment are with their first plate broad side 1 1 a on the strip inner surfaces 1 9a. The semitrailer stones 1 1 of the second embodiment lie with the two first step surfaces 4 a on the strip inner surfaces 1 9a. In addition, the second step surfaces 4b adjacent to the strip side surfaces 1 9c arranged and the first plate broadsides 1 1 a preferably close flush with the Leistenau ßenflächen 1 9b.

The semitrailer stones 1 1 are preferably not mortared or glued to the suspension rocks 9. They are arranged next to one another in the tunnel width direction 7b and preferably abut with their first plate edge surfaces 11c together. The Aufliegersteine 1 1 thus form several, in particular continuous, in the tunnel width direction 7b extending, horizontal Aufliegersteinreihen 23, each one Aufliegersteinreihe 23 between two rows of hanging rows 22 is arranged. Between individual in tunnel width direction 7b mutually adjacent horizontal Aufliegersteinen 1 1 is preferably also an expansion joint present, which is filled with ceramic fibers.

In this case, the semitrailer stones 1 1 are preferably arranged such that a semi-trailer stone 1 1 rests on at least two suspension rocks 9 of a suspension line 22. This prevents a Aufliegerstein 1 1 falls down, should a Auflagerleiste 1 9 cancel.

Preferably, both between the strip inner surfaces 1 9a of the Auflagerleisten 1 9 and the first and lower plate broad side 1 1 a or the first step surface 4a of the semitrailer stones 1 1 and between the second Platten- edge surfaces 1 1 d of the semitrailer stones 1 1 and the second beam side surfaces 1 7b each have a fiber paper layer 24, 25 present. The deformable fiber paper layers 24, 25 serve to enable and compensate for the stretching and shrinking of the hanging stones 9 and the semitrailer stones 1 1 due to changing temperature loads. They each consist of several in the tunnel width direction 7b adjacent to each other and juxtaposed individual fiber papers 26, 27th The fiber papers 26 of the first fibrous paper layer 24 are preferably made of ceramic fibers. And the fibrous papers 27 of the second fibrous paper layer 25 preferably also consist of ceramic fibers.

In the context of the invention, it is of course also that only a fiber paper layer is present, which both between the strip inner surfaces 1 9a and the lower plate broad side 1 1 a of the semitrailer stones 1 1 and between the second plate edge surfaces 1 1 d and the second Beam side surfaces 1 7b is arranged and formed by folded over fiber papers (not shown).

As already explained, each of the Aufliegersteinreihen 23 an insulating layer 1 2. The insulating layer 1 2 preferably comprises a layer 28 of plate-shaped refractory bricks 29 of refractory material, a first, second and third thermal barrier coating 30, 31, 32, a steel foil layer 33 disposed between the second and third thermal barrier coatings 31, 32, and a layer 34 of barrier panels 35 on. The individual layers or layers 28, 30-34 of the insulating layer 1 2 are in turn preferably not mortared or glued to one another or to the semitrailer stones 1 1.

The refractory bricks 29 are, in particular directly, on the Aufliegersteinen 1 1 on. They are arranged next to one another in the tunnel width direction 7b and optionally in the tunnel longitudinal direction 7a. In addition, they preferably consist of basic refractory material with direct ceramic bond according to DIN EN ISO 1 0081: 2005-05 or of clay or chamotte. Between the plate edge surfaces 29c of the refractory bricks 29 and the second beam side surfaces 17b, the second fibrous paper layer 26 is preferably also present. The refractory bricks 29 may have a lower fire resistance than the firebox side or kiln side arranged Aufliegersteine 1 1. They serve as the first barrier layer to prevent the penetration of alkali vapors.

On the layer 28 of refractory bricks 29, preferably directly, the first thermal barrier coating 30 is disposed. This consists of in the tunnel width direction 7b and optionally in the tunnel longitudinal direction 7a juxtaposed Isolierwollmatten 36 made of insulating wool. The insulating wool is preferably high-temperature ceramic wool in accordance with DIN EN 1 094-1: 2008-09.

On the first thermal barrier coating 30, in particular directly, the second thermal barrier coating 31 is arranged. This also consists of tunneling width direction 7b and optionally in the tunnel longitudinal direction 7a juxtaposed Isolierwollmatten 37 made of insulating wool. The insulating wool is preferably also high-temperature ceramic wool DIN EN 1 094-1: 2008-09. The insulating wool of the second thermal barrier coating 31 may have a lower fire resistance than the insulating wool of the first thermal barrier coating 30.

The steel foil layer 33 is arranged on the second heat-insulating layer 31, preferably directly. This consists of in the tunnel width direction 7b and optionally in the tunnel longitudinal direction 7a juxtaposed steel sheets 38. The steel foil layer 33 serves for gas sealing. The individual steel foils 38 each preferably have a thickness of 0.05 to 1 mm. In addition, the adjoining steel sheets 38 are arranged so that they overlap each other in areas, to ensure a secure gas seal the furnace channel 6. The steel foils 38 can also be glued together by means of a ceramic adhesive for even better sealing.

On the steel foil layer 33, preferably directly, the third thermal barrier coating 32 is arranged. This also consists of in the tunnel width direction 7b and optionally in the tunnel longitudinal direction 7a juxtaposed Isolierwollmatten 39 made of insulating wool. The insulating wool is preferably mineral wool. The insulating wool of Isolierwollmatten 39 must not be fireproof due to the low temperature stress. The insulating wool of the third thermal barrier coating 32 thus preferably has a lower fire resistance than the insulating wool of the second thermal barrier coating 31. The third thermal barrier coating 32 serves on the one hand for thermal insulation and on the other for weighting the steel foil layer 33 so that it can not wave.

On the third thermal barrier coating 32, preferably directly, the layer 34 is arranged from blocking plates 35. The blocking plates 35 are in tunnel width direction tion 7b and optionally in the tunnel longitudinal direction 7a arranged side by side. The barrier plates 35 need not have high fire resistance. They consist for example of concrete or chamotte. They only serve to protect the insulating wool of the third heat-insulating layer 32. They are intended in particular to prevent the insulating wool of the third heat-insulating layer 32 from being entrained by cooling air flowing over it. The blocking plates 35 preferably have a thickness of 1 0 to 25 mm.

Advantage of the tunnel kiln 1 according to the invention is that the basic suspension rocks 9 according to the invention and the semitrailer stones 1 1 according to the invention have a significantly higher resistance to alkali than the previously known burned suspended rocks from chamotte. This significantly extends the furnace life while reducing maintenance and repair costs. In particular, the suspended ceiling 5 according to the invention is no longer a "wear blanket" which loses an approximately 1 cm thick layer of material per year The increased alkali resistance results in particular from the basic raw materials used.

The use of the basic hanging rocks 9 and 1 Aufliegersteine 1 was not readily obvious, since they are initially more expensive to produce than acidic stones from chamotte. In addition, the basic hanging rocks 9 have a higher thermal conductivity, which is also disadvantageous and must be compensated by adjusting the construction of the suspended ceiling 5 by adjusting the insulation. In addition, the variation of the stone form of the directly ceramically bound, basic hanging stones 9 due to the low plasticity of the molding compound is not so great as in the prior art stones. They also have a lower elasticity.

The structure of the insulating layers 1 2 of the insulating wool mats is therefore advantageous because they ensure a very good insulation with low weight. For putting in a drywall installation is possible. And it is possible to heat up quickly, they do not contain water. It is also within the scope of the invention that the suspended ceiling 5 according to the invention is not designed as a flat ceiling, even if this is preferred. The suspended ceiling 5 may be formed, for example, as a vaulted ceiling with vault-like Aufliegersteinen.

The semitrailer stones 1 1 can also in a conventional manner from one to the other plate broad side 1 1 a; b continuous semicircular recesses 40 for the connection of burner tubes 41 have (Figure 1), if it is a ceiling-fired tunnel kiln 1. Two mutually adjacent semicircular recesses 40 then form a circular recess. Or the semitrailer stones 1 1 can also in a conventional manner from one to the other plate broad side 1 1 a, b continuous circular recesses for the connection of the burner tubes 41 have (not shown). The circular recesses are introduced by drilling after firing. But it may also be a side burner tunnel kiln 1 without such burner tube recesses.

In addition, other means of transport for the kiln than the kiln cars are within the scope of the invention.

Furthermore, another structure of the insulating layer 1 2 is within the scope of the invention. Depending on the thickness of the semitrailer stones 1 1 and the temperature load, for example, the refractory bricks 29 can be omitted. In addition, the number of heat-insulating layers 30, 31, 32 can be varied. Instead of insulating wool, one or more thermal insulation layers 30, 31, 32 can also consist of thermal insulation boards, refractory bricks or insulating concrete if sufficient drying can be ensured. If thermal insulation panels are present as the uppermost thermal barrier coating, the barrier panels 35 can be omitted. Furthermore, beds can also be used. In addition, the suspension rails 1 8 can protrude in a conventional manner from the first beam side surfaces 1 7a. The suspension brackets 1 0 are then adjusted accordingly.

In addition, the hanging stones 9 or Aufliegersteine 1 1 also consist of firmly connected to each other, in particular bonded, moldings, which each consist of the basic material.

Furthermore, it is particularly advantageous if the two side walls 3 on the firing side also have magnesia stones or magnesia-chromite stones or magnesia-zirconia stones according to DIN EN 1 0081 -2: 2005-05. This at least in a portion of the tunnel kiln 1, which is highly stressed. The same applies to the suspended ceiling 5. These can also have the suspension rocks 9 and semitrailer stones 1 1 according to the invention only in a partial area of the tunnel kiln 1, depending on the load of the tunnel kiln 1.

Claims

claims

Burnt hanging stone (9) of refractory material with a ceramic bond for a suspended ceiling (5) of a tunnel kiln (1) for the ceramic industry, in particular for brickwork, with receiving elements (19) for receiving a semi-trailer stone (1 1) of the suspended ceiling (5), characterized in that

the hanging stone (9) is a magnesia stone or a magnesia chromite stone or a magnesia-zirconia stone according to DIN EN ISO 10081 -2: 2005-05.

Hanging stone (9) according to claim 1,

characterized in that

the hanging stone (9) is a magnesia brick of at least the group M 90 according to DIN EN ISO 10081 -2: 2005-05 or a magnesia chromite brick of at least the group MCr 70 according to DIN EN ISO 10081 -2: 2005-05.

Hanging stone (9) according to one of the preceding claims,

characterized in that

the hanging stone (9) in the form of a double-T-beam is formed and one, in particular cuboidal, middle bar (17) and two, in particular cuboid, suspension rails (18) and two, in particular cuboid, support strips (19), wherein the Suspension rails (18) at a first beam end of the central bar (17) connect to this and project from this in opposite directions and the Auflagerleisten (19) at a second beam end of the central bar (17) adjoin and protrude from this in opposite directions.

Suspended ceiling (5) for a tunnel kiln (1) for the ceramic industry, in particular for brickwork, the suspended ceiling (5) having a number of suspension rock (9) made of refractory material, which are adjacent to each other to form a plurality of mutually adjacent horizontal Hangesteinreihen (22) and wherein the suspended ceiling (5) on the firehole side more on the suspension rocks (9) resting burned Aufliegersteine (1 1) made of refractory material which are each arranged between two rows of hanging blocks (22) to form in each case a horizontal row of semi-conductor blocks (23),

characterized in that

each of the suspension rocks (9) and the semi-trailers (1 1) is magnesia or magnesia-chromite or magnesia-zirconia according to DIN EN ISO 10081 -2: 2005-05.

Suspended ceiling (5) according to claim 4,

characterized in that

each of the suspended rocks (9) and semi-trailers (1 1) comprises magnesia bricks of at least the group M 90 according to DIN EN ISO 10081 -2: 2005-05 or magnesia chromite bricks of at least the group MCr 70 according to DIN EN ISO 10081 -2: 2005-05 acts.

Suspended ceiling (5) according to claim 4 or 5,

characterized in that

the suspended ceiling (5) has a plurality of bar-shaped ceiling beams (8) arranged adjacent to one another, on which the hanging blocks (9) are suspended adjacent to one another, forming one of the rows of hanging blocks (22).

Suspended ceiling (5) according to one of claims 4 to 6,

characterized in that

the support strips (19) of the suspension blocks (9) of mutually adjacent hanging stone rows (22) face each other, wherein the semitrailer blocks (1 1) rest on the mutually facing support strips (19).

8. Suspended ceiling (5) according to claim 7,

characterized in that

between the center beam (1 7) and the Aufliegersteinen (1 1) and preferably between the Auflagerleisten (1 9) and the Aufliegersteinen (1 1) each have a fiber paper layer (24; 25) is arranged.

Suspended ceiling (5) according to one of claims 4 to 8,

characterized in that

the suspended ceiling (5) a plurality of insulating layers (1 2), wherein in each case an insulating layer (1 2) on a Aufliegersteinreihe (23) is arranged.

Suspended ceiling (5) according to claim 9,

characterized in that

the insulating layers (1 2) each have at least two thermal barrier layers (30; 31; 32) and a steel foil layer (33) arranged therebetween for gas sealing.

1 1. Suspended ceiling (5) according to claim 9 or 10,

characterized in that

the insulating layers (1 2) starting from the Aufliegersteinreihe (23) each have a layer (28) of plate-shaped refractory bricks (29) made of refractory material, a first, second and third thermal barrier coating (30; 31; 32), one between the second and third Thermal insulation layer (31; 32) arranged steel foil layer (33) and one on the third

Heat insulating layer (32) arranged layer (34) of blocking plates (35), wherein preferably the individual layers and layers (28; 30-34) of the insulating layers (1 2) with each other and with the Aufliegersteinen (1 1) are not mortared or glued ,

12. suspended ceiling (5) according to claim 1 0 or 1 1,

characterized in that

the steel foil layer (33) consists of a plurality of mutually adjoining steel foils (38), wherein the adjoining steel foils (38) are preferably arranged such that they overlap each other in regions, and wherein the steel foils (38) preferably have a thickness of 0 , 05 to 1, 0 mm.

Suspended ceiling (5) according to one of claims 10 to 12,

characterized in that

the thermal barrier coatings (30; 31; 32) each consist of at least one insulating wool mat (36; 37; 39) of ceramic insulating wool.

Tunnel kiln (1) for the ceramic industry, in particular for brickworks,

characterized in that

the tunnel kiln (1) has a suspended ceiling (5) according to one of claims 4 to 13.

Tunnel kiln (1) according to claim 14,

characterized in that

the tunnel kiln (1) has an oven tunnel (2) and transport means for transporting kiln material through the kiln tunnel (2), the kiln tunnel (2) preferably having two tunnel side walls (3), a tunnel foundation slab and the suspended ceiling (5).

Tunnel kiln (1) according to claim 15,

characterized in that

the side walls of the tunnel (3) have magnesia stones or magnesia-chromite stones or magnesia-zirconia stones according to DIN EN ISO 10081 -2: 2005-05 on the firing side. Use of a refractory magnesium or magnesia-chromite stone or magnesia-zirconia stone according to DIN EN ISO 1 0081-2: 2005-05 with direct ceramic bond as a semi-conductor stone (1 1) of a suspended ceiling (5) and / or as a combustion chamber side stone of a tunnel side wall (3) a tunnel kiln (1) for the ceramic industry, in particular for brickworks.