DE4217100A1 - Mfg. long chimney stack with inner tube in concrete casing - uses through-shaped mould to produce two half-shell sections which are bonded around central tube. - Google Patents

Abstract

The precast concrete chimney sections are produced in two halves. The mould (2) has a base (5) shaped to form a semi-circular recess in the cast concrete. Along the semi-circular mould, are two inflatable secondary mould shapes (6), made of a flexible, air-tight material for ventilation grooves in the wall of the semi-circular sections. The concrete is cast with the secondary forms deflated. Inflation assists in compacting the concrete. On hardening, the inflation pressure is increased to assist in the release of the formwork. The chimney is formed by encasing a central tube in insulation, and encasing them in two matching sections of the concrete section which are bonded and bolted together. ADVANTAGE - Allows for longer chimney sections of narrow cross sections to be mfd.

Description

The invention relates to a method according to the preamble of claim 1. a prefabricated fireplace according to the preamble of claim 7 and a casting mold according to the preamble of claim 8.

It was already known to manufacture prefabricated chimneys from pairs of molded parts in the form of To manufacture chimney half-shells. Each of a pair of fireplace half shells Chimney half-shells were large with a semicircular recess Diameter on the inside for receiving an inner tube, d. H. egg provided a chamotte tube. Parallel to this semicircular recess In the longitudinal direction, groove-like ventilation ducts ran out long. Several pairs of chimney half-shells were installed during the assembly of mins piled up in the house to make the entire fireplace.

It was disadvantageous that the chimney half-shells only up to a certain comparatively short length could be produced because the chimney half-shells otherwise when lifting out of the molding box using a hoist would be broken. For this reason, we had to manufacture the whole Fireplaces several pairs of fireplace half-shells are piled on top of each other. A Another disadvantage was that conventionally none for the groove-like ventilation ducts Undercuts could be produced, but this led to the formation of a vent tion train with satisfactory size and Geometry is required. Another problem with conventional prefabricated ka mines has been found that the thrust transmission between the two chimney half-shells was not solved satisfactorily, so that is why Due to the transport and wind load, do not wear 50 long, free the fireplace half-shells were considered by the specialist, but rather smaller lengths, each inserted between the building floors were tense.

The invention has for its object a method for producing Chimney shells, a prefabricated fireplace and a mold for its manufacture  to create what a long, one-piece chimney or a possible longest, one-piece chimney section can be realized, which high Can withstand loads and also with suitable Geome ventilation ducts trie is provided.

This object is achieved by the method with the features solved in the characterizing part of claim 1. Furthermore, this will Task through the prefabricated fireplace after the characteristic part of the contract Proverb 7 and through a mold according to the characterizing part of the An Proverb 8 solved.

According to the method according to the invention, on the one hand undercut be manufactured because the formwork core with internal pressure is struck and this internal pressure for the purpose of lifting out the finished one hardened chimney shell can be drained again, creating a Lifting out the chimney half-shell despite forming an undercut when the formwork core slackens again.

In order to be able to remove the finished chimney shell from the mold, the In internal pressure in the formwork core after the chimney half-shell has hardened increases, which detaches them evenly from the walls of the mold becomes. This allows very long lengths, for example 12 m long Chimney shells, lift out of the formwork without the risk of Breaking is given.

According to an advantageous development of the invention, one is in shape longitudinally extending hose provided as a formwork core, the Cross-sectional area through hydraulic or pneumatic lower or Overpressure can be reduced or enlarged. Preferably a fabric hose, for example a fire hose, can be used, which with sufficient strength and stability also sufficiently elastic and there with is stretchy.

According to another advantageous development of the invention, the for the production of different chimney lengths in variable lengths Longitudinal racks for the end walls of the Chimney half-shell the hose by means of a form-fitting recess and the Longitudinal racks are non-positively by inflating the hose on  Fixed circumference of the hose. This has the advantage that the longitudinal rack can be fixed without any additional effort by inflating the tube and can no longer shift even with strong vibrations. However, it is also another, conventional fixation of the longitudinal racks, for example possible with screws.

According to further advantageous embodiments of the invention, either the chimney half-shells that form the finished chimney by putting them together held together by flanges formed on it, which by Spann screws, reinforcements or the like are interspersed, or are the clamping elements through within the recesses they have penetrated around them poured concrete fixed in position, whereby advantageously the adjacent flan surfaces of the chimney half-shells forming the outer jacket are glued. You can either use the clamping screws or the poured concrete, usually in connection with a piece of construction that is thereby fixed steel, the only fastening of the chimney half-shells to each other, whereby however, for better durability, the adhesive is also recommended.

In the fireplace according to the invention, it is due to the invention large length of its sections easily possible, the top one Clamp section in both floors of the building and so because of of the wind load on the chimney. It is however, with a suitable attachment it is also possible, the top one Clamp section only in the top building ceiling.

In the casting mold according to the invention, at least one is advantageously in shape running in the longitudinal direction, embedded in the jacket of the molded bead, for Position fixing of the hose serving groove provided the side walls with the groove giving a dovetail-like cross-section intersections are provided; and on the outside of the hose are in the longitudinal direction of which, in the groove insertion position of the hose Undercuts provided behind fixing ribs. You can preferably the fixing ribs by a in the hose in its longitudinal direction inserted fixation strip be formed, their mutually essentially parallel The long side edges give the distance between the undercut Groove side wall areas have a corresponding distance from each other, so that a fixing strip with the interposition of a jacket area of the Hose between itself and the groove bottom and the groove side walls in  the undercut area of the fixing groove can be inserted. This offers the Advantage that the hose is easily attached to the bead the can and seals to the dovetail groove when he is inflated. As a result, no liquid concrete can penetrate the groove. It is however, any other type of attachment of the hose to the shaped bead possible, for example attaching by gluing.

According to another advantageous embodiment, they are in the longitudinal direction running sidewalls of the form gutter removable or pivotable on Bottom of the mold attached. The swiveling can be done by a joint or the elasticity of the trough can be achieved.

The longitudinal racks for producing different chimneys are preferred lengths fixable in different length positions. This can be done in discrete Distances occur, for example with the help of positioning projections.

According to an advantageous development of the invention, two are on the mold base arranged side strips flanking the molded bead on both sides for molding of the flange surfaces along which the two chimney half-shells rest against each other when the fireplace is installed. They are preferred upward in the substantially flat surfaces of the side strips standing projections for the formation of nest-like Excavations provided for the inclusion of pressure sensitive adhesive mortar. You can the projections evenly distributed in the longitudinal direction of the mold, in particular in an egg Nem fixed spacing should be arranged such that at the finished fireplace stacked chimney half-shells the recesses over each other cover. This configuration results in the applied Pressure sensitive adhesive for gluing two chimney half-shells together in the opposite depressions a pressure sensitive adhesive ball, which the thrust between the half-shells. This type of "interlocking" leaves produce themselves particularly inexpensively, since the two chimney half shells are identical and the troughs by simple projections in the formwork can be formed in the area of the flange surfaces. A particularly advantageous transmission of thrust results from that the base of the projections adjacent to the side strips as a cylinder coat is formed.

The longitudinal racks with locking recesses can then advantageously be placed on the  effective projections can be placed in the manner of a fixing catch. How nice mentioned above, the longitudinal racks can also be fixed that they have a hose area protruding beyond the molded bead overlap by means of a form-fit recess and by inflating the Hose can be non-positively attached to this.

The invention is un based on preferred embodiments ter explained with reference to the drawing. The drawing shows:

Figure 1 is an overall perspective view of the mold immediately before pouring with concrete.

FIG. 2a to 2c sectional views of the casting mold which xiervorgang the insertion and Fi illustrate by Längsabstellern;

Figure 3 shows an overall perspective view of the casting mold immediately before pouring with concrete, partly in section and with transparently presented longitudinal racks.

Fig. 4a to 4h sectional views of the casting mold, which represent the entire manufacturing process of the chimney half-shell precast elements in time consecutive order;

FIG. 5a to 5c-sectional views of the finished fireplace, which constitute the final assembly of the prefabricated chimney;

Fig. 6 shows an assembly example of a two-part prefabricated chimney in a house;

Figure 7 is a schematic, perspective view of the finished fireplace with the acting thereon bending stress. and

Fig. 8a to 8f partial sectional views of possible before jump / Ausmuldungspaarungen for receiving the Schubbela stung, which prevails between the two chimney shells.

In Fig. 1 is an overall view of the ready for filling with concrete stationary mold is shown. It can be seen an upwardly open mold box with an elongated channel 1 , which is substantially ausgebil det of longitudinally extending side walls 2 and the mold bottom 3 . The trough 1 is divided by longitudinal racks 4 . The Längenab adjuster 4 can be arranged at such a distance from one another that either half-length chimney shells extending over the entire length of the chimney or any partial lengths thereof can be produced. A molding bead 5 runs along the molding channel 1 , which is surrounded along a part of the length by the longitudinal racks 4 on the one hand and over its entire length by the molding channel 1 on the other hand, with the molding bead 5 on the mold plate 3 of the molding channel 1 standing up against the molding bead 5 relative to the Form gutter 1 is fi xed. Between the bead 5 and the longitudinal racks 4 two expandable hoses 6 are arranged as formwork cores, the cross-sectional areas of which can be varied by changing a hydraulic or pneumatic overpressure prevailing in the hoses 6 . The hoses 6 can also be evacuated in order to assume a completely contracted state. To generate the desired overpressure or underpressure, the hoses 6 are closed by means of the lines 7 to a pressure source, for example to a pump.

In the molded bead 5 serving to fix the position of the two hoses 6 grooves 8 are embedded, the grooves 8 each having an undercut 10 and thus giving the respective groove 8 a dovetail cross-section. A fixing rib 9 is arranged in each case in the interior of the tube 6 and pushed behind the undercut 10 , so that the tube 6 is fixed to the shaped bead 5 .

As is further indicated schematically in FIG. 1 by means of arrows, on the one hand the longitudinal rack 4 can be removed from the molding channel 1 and on the other hand the side walls 2 can be folded away to the side, either with the help of between the side walls 2 and the mold base 3 existing joints or solely by the elasticity of the channel 1 , for example made of sheet metal. The mold channel 1 can also be designed such that the side walls 2 can be completely detached from the mold base 3 .

In FIGS. 2a to 2c is shown how the 4 Längsabsteller be züglich the form of trough 1 are mounted. As can be seen from Fig. 2a, the longitudinal racks 4 are provided with undercuts 11 . After the form channel 1 has been assembled with the molding bead 5 and the hoses 6 have been fixed to the molding bead 5 by means of the fixing rib 9 designed as a stiffening strip, the air must first be removed from the tubes 6 so that the tubes 6 assume their contracted state. If necessary, the air can even be evacuated by suction. The longitudinal racks 4 can now be inserted into the channel 1 as shown in FIGS . 2a and 2b. For positioning, the trough 1 is also provided with positioning projections 12 , which can engage in respective positions 13 , which are formed in the respective longitudinal rack 4 .

As can be seen from FIG. 2c, the tubes 6 reach behind the undercuts 11 by inflating them with compressed air or filling them with a hydraulic fluid under pressure, and thus fix the longitudinal racks 4 with respect to the form channel 1 . The longitudinal racks 4 are fixed in such a way that they do not shift even under strong vibrations. Due to the undercutting conditions 11 , the longitudinal racks 4 can only be removed from the trough 1 again when the air or the hydraulic fluid has been let out of the hoses 6 .

Another positive effect of the type of assembly of the tubes 6 on the shaped bead 5 results from the fact that a self-sealing device between the tubes 6 and the shaped bead 5 is achieved at the point at which the tube 6 is attached to the shaped bead by the inflation 5 trained undercut 10 touches. This self-sealing ensures that no concrete can penetrate into the grooves 8 formed in the bead 5 .

Fig. 3 shows essentially a representation as already shown in Fig. 1, wherein it is clear how the only longitudinal rack 6 exemplarily shown here is clamped by the inflated hoses 6 . In addition, there is a savings body 14 for forming a larger recess in the chimney shell 17 to be produced. The recess body 14 between the inflated tube 6 and the side wall 2 of the form channel 1 is also clamped in such a way that it can not be displaced even in the event of strong vibrations, just like the longitudinal stop 4 . A precise positioning of the recess body 14 can also be done by the positioning projections 12 , which can engage in a corresponding recess in the recess body.

If, as shown in FIGS. 1, 2c and 3, the longitudinal racks 4 and, if appropriate, the recess bodies 14 are mounted and the hoses 6 are inflated, the molding box is ready for pouring out concrete.

A corresponding sequence of the individual steps in the production of the fireplace half-shell is shown in FIGS. 4a to 4h:

As shown in Fig. 4a, the longitudinal rack 4 is first fixed in the mold channel 1 after the mold bead 5 has been fixed in the mold channel 1 and the hoses 6 have in turn been fixed to the mold bead 5 . The hoses 6 are depressurized or possibly also evacuated. A system of positioning protrusions 12 and positioning recesses 13 can be provided, which can help in positioning the longitudinal racks 4 in the form channel 1 .

As is shown in FIG. 4b, the tubes 6 are now inflated, for example with air, to a pressure of 1 bar, as a result of which the longitudinal stops 4 are fixed in the manner described above. A reinforcement basket 15 can be inserted into the molded box thus formed.

As shown in Fig. 4c, the molding box is now filled with concrete 16 and the concrete is compacted, whereupon the concrete hardens as shown in Fig. 4d.

As shown in Fig. 4e, the hoses 6 , for which particularly lightly elastic fabric hoses, for example fire hoses, NEN, are inflated with a pressure greater than one bar (<1 bar), causing the hoses 6 to expand somewhat and thereby the manufactured Detach the chimney shell 17 over the entire length of the formwork, ie detach from the form channel 1 , the bead 5 , the longitudinal racks 4 and, if necessary, the recess bodies 14 and the hoses 6 themselves. Since the Ka min half-shell 17 is usually a very slim, for example over the entire length of the chimney concrete part of 12 m in length, the pre-detachment by means of the hoses 6 prevents the Ka half-shell 17 from breaking during mechanical demoulding, which otherwise, for example, when stripping by means of a crane.

According to FIG. 4f, the air is now let out of the tubes 6 , whereupon the tubes 6 are depressurized or the air therein is even evacuated. The chimney shell 17 is now suspended from a hoist, for example a crane, and is pulled out of the formwork by the latter according to FIG. 4g.

According to Fig. 1 in the form of channel, the Formwulst 5, the hoses 6 so as Längsabsteller 4 purified 4h. The longitudinal racks 4 are preferably made of plastic so that buildup of concrete can be removed more easily.

In FIGS. 5a to 5c, the assembly of the finished fireplace from the two fireplace half-shells 17, a pubic Otter ear 18, an insulating jacket 19, two Schrau ben 20 and corresponding nuts 21 as well as pressure sensitive adhesive 22 is shown, wherein the pressure-sensitive adhesive 22 in specially designated hollowing 25 is introduced, which were formed by means of projections 23 formed on the groove 1 in the substantially flat flange surfaces 24 . Before jumps can also be identical to the positioning projections 12 , so that the positioning projections 12 have the double function of positioning the longitudinal racks 4 at the appropriate location and at those locations which are not covered by the longitudinal racks 4 , the troughs 25 in the flange surfaces 24 to form . The positioning projections 12 , which in this case are identical to the projections 23, can be arranged at regular intervals.

As shown in Fig. 5a, is first inserted the insulating jacket 19 during the final assembly of the fireplace in the Ka minhalbschale 17 which may be made of glass fiber or mineral fiber wool. Subsequently, the fireclay tube 18 is inserted into a channel of the chimney half shell 17 lined by the insulating mat 19 .

According to FIG. 5b, the insulating mat 18 is now closed in a tubular manner around the fire tube 18 and held in this position with an adhesive strip only for assembly purposes. The two flange surfaces 24 along which the two chimney half-shells 17 are glued to one another are coated with the special pressure-sensitive adhesive 22 . In particular, the depressions 25 are filled with pressure sensitive adhesive. When the two chimney half-shells 17 are placed on top of one another, the troughs 25 of the two chimney half-shells 17 are each arranged exactly opposite one another.

As can be seen from Fig. 5c, the two chimney shells 17 are firmly screwed together with the two screws 20 and nuts 21 , whereby it is alternatively also possible to insert a piece of structural steel into the cavities in the chimney and then the cavities with one To seal grout. The through holes 26 for the screws or for the encapsulation of the structural steel can either be made by inserting a plastic tube into the formwork before pouring with concrete or can be drilled ge.

Fig. 6 shows an installation example for a two-part fireplace in a house. Usually, however, a one-piece chimney will be installed. A one-piece fireplace with a length of up to 12 meters can be easily manufactured. At larger storey heights, as is the case in Fig. 6, the chimney must be divided across a dividing line 27 or at several such dividing lines. However, it should be ensured that the last, continuous piece of the fireplace, which leads outside, is clamped in the last two upper floor ceilings 28 and 29 , so that the fireplace against kinking is safe due to the wind load on the off protruding from the roof acts part 30 of the fireplace.

As shown in FIG. 7, the chimney, which is up to 12 m long, is subjected to severe bending stress due to its great length during transport and, even if it is installed in the house, due to the wind load. The load occurring there is indicated in Fig. 7. Strong shear stresses occur between the two Ka half shells 17 along the flange surfaces 24 . It was determined from experiments that the bending strength of the chimney increases very strongly if 24 high shear forces can be transmitted along the flange surfaces.

As 8a can be seen from Fig., The hollowing are 25 of the two fireplace half-shells 17 each exactly opposite and in gluing together of the two fireplace half-shells 17, this hollowing fill 25 having Haftkle bemörtel 22 and so give a toothing which high shear forces can übertra gene.

As shown in Fig. 8b, alternatively may be a first toothing system ver turns are, according to which the hollowing 25 are formed on one of the two half-shells 17 and chimney are formed on the other half-shell chimney 17 corresponding to projections 31. In contrast to the embodiment shown in FIG. 8a, the shear forces are transferred directly to the same chimney half-shell material, i.e. the concrete, while according to the embodiment in FIG. 8a, the shear forces with the aid of the adhesive mortar ball made of pressure-sensitive adhesive enclosed in the recesses 25 22 are transmitted.

The influence of the shape of the recesses 25 or projections 31 on the load distribution is explained with reference to FIGS . 8c to 8f.

If it is as shown in Fig. 8c troughs with hemispherical shape, the thrust forces are deflected and thus receive a component that drives the chimney half-shells 17 apart, whereby they tend to break apart. Although this can be prevented by an increased number of screws 20 which are arranged at a smaller distance from one another, this leads to an unnecessarily high outlay.

According to the embodiment according to FIG. 8d, the recess 25 in the area of the flange surfaces 24 has a cylindrical area 32 , via which the thrust forces are transmitted. This creates no force component, which che the chimney shells 17 apart. The thrust forces are therefore optimally transmitted here.

A corresponding comparison applies to the embodiments 8 e and 8 f with protrusions 31 engaging in recesses 25 . Analogously, also in the embodiment according to FIG. 8e with hemispherical recesses 25 or projections 31, a force component which drives the chimney half-shells 17 apart, which in the embodiment according to FIG. 8f by means of the optimal thrust transmission over an existing cylindrical area 33 is avoided.

Reference list

1 trough
2 side wall
3 molded bottom
4 longitudinal racks
5 molded bead
6 hose
7 line
8 groove
9 fixing rib
10 undercut
11 undercut
12 positioning projection
13 positioning recess
14 recess body
15 reinforcement cage
16 concrete
17 fireplace half-shell
18 fire tube
19 insulating mat
20 screw
21 mother
22 pressure sensitive adhesive
23 head start
24 flange surface
25 exemptions
26 through hole
27 dividing line
28 floor ceiling
29 floor ceiling
30 outstanding part
31 head start
32 cylindrical area
33 cylindrical area

Claims (19)

1. Method of making prefabricated chimneys of great length with

• - an inner tube and
• - An outer jacket surrounding the inner tube and preferably made of reinforced concrete, which is provided on its inside with groove-like ventilation ducts extending in the longitudinal direction, characterized by the following process steps:
• a) Providing a trough-like casting mold for producing a chimney half shell, in particular a chimney half shell of the outer jacket
  • - With on the bottom of the casting mold extending in the longitudinal direction in the manner of a cylinder jacket segment, for example, shaped bead for shaping the inner surface and
  • - with at least one formwork core which projects beyond the bead and serves to form a ventilation duct and also runs in the longitudinal direction,
    • - Its shaping surface is formed by a bendable and stretchable, pressure-tight jacket and
    • which can be changed in its cross-sectional shape and / or in its cross-sectional dimensions by changing the internal pressure,
• b) filling the casting mold with concrete and compacting with a predetermined cross-sectional shape of the formwork core produced by corresponding internal pressure control,
• c) widening of the formwork core after the hardening phase and thereby releasing the chimney half-shell from the walls of the mold,
• d) Completion of the finished chimney by inserting the inner tube into the half-shell and closing the outer shell by attaching at least one additional half-shell, optionally with an insulating layer between the outer shell and the inner tube.

2. The method according to claim 1, marked by  a tube extending in the longitudinal direction of the form as a formwork core, whose cross-sectional area by hydraulic or pneumatic lower or Overpressure can be reduced or enlarged. 3. The method according to claim 1 or 2, characterized, that for the production of different chimney lengths in variable lengths Longitudinal racks for the forehead that can be positioned in the mold walls of the chimney half-shell the hose by means of a form-fit recess overlap and non-positive by inflating the hose are fixed on the circumference of the hose. 4. The method according to any one of claims 1 to 3, characterized, that the chimney half forming by putting together the finished chimney shells held together by clamping screws, reinforcements or the like the flanges attached to the chimney half-shells Zen. 5. The method according to claim 4, characterized, that the tensioning elements by within within them are fixed around this poured concrete. 6. The method according to one or more of the preceding claims, characterized, that the abutting flange surfaces of the outer jacket bil the fireplace half-shells are glued together. 7. From several multi-shell individual segments according to the method described in the vorste existing claims manufactured fireplace, characterized in that the upper chimney piece has at least a length that extends from the top edge of the penultimate floor ceiling ( 28 ) to the chimney mouth above the building roof. 8. Casting mold for producing a chimney half-shell for the method according to one of claims 1 to 6 with an upwardly open molding box, the longitudinally extending side walls of which form an elongated molding channel with the mold bottom, the at least one end of which can be closed by a longitudinal rack that can be positioned in the molding channel , marked by

• - A forming the middle mold floor area and with the union of the same cross-sectional shape over the length of the mold bulges ( 5 ) to shape the inner surface of the chimney shell ( 17 ) or the mantle and
• - by at least one
  • - extending in the longitudinal direction of the mold over the length of the molded bead ( 5 ),
  • - embedded in the bead ( 5 ) and
  • - With part of its circumference over the jacket of the molded bead ( 5 ) projecting expandable hose ( 6 ) as a formwork core for a ventilation duct lying on the inner surface of the chimney jacket, the cross-sectional area of the hose ( 6 ) being increased or reduced by hydraulic or pneumatic pressure increase or pressure reduction is scalable.

9. Casting mold according to claim 8, characterized in that the hose ( 6 ) consists of a textile fabric, for. B. is a fire hose. 10. Casting mold according to claim 8 or 9, characterized by

• - At least one groove ( 8 ) running in the longitudinal direction of the mold in the jacket of the molded bead ( 5 ) and used to fix the position of the tube ( 6 ), the side walls ( 2 ) of the undercuts ( 10 ) with the groove ( 8 ) giving a swallow-tooth-like cross-section are provided; and through
• - On the outside of the hose ( 6 ) in its longitudinal direction duri fende, in the groove insert position of the hose ( 6 ) the undercuts ( 10 ) engaging fixing ribs ( 9 ).

11. Casting mold according to claim 10, characterized in that the fixing ribs ( 9 ) are formed by a fixation strip inserted into the tube ( 6 ) in its longitudinal direction, whose mutually parallel longitudinal side edges have a distance from one another which corresponds to the distance between the undercut groove side wall regions on, so that a fixing strip with the interposition of a jacket region of the hose ( 6 ) between itself and the groove bottom and the groove sides walls can be inserted into the undercut region of the groove ( 8 ). 12. Casting mold according to one of claims 8 to 11, characterized in that its longitudinally extending side walls ( 2 ) are attached to the mold base ( 3 ) in a removable or pivotable manner. 13. Casting mold according to one of claims 8 to 12, characterized in that its longitudinal racks ( 4 ) can be fixed in different lengths for producing different chimney lengths. 14. Casting mold according to one of claims 8 to 13, characterized by two on the mold base ( 3 ) arranged, the molding bead ( 5 ) flankie on both sides side strips for forming the flange surfaces ( 24 ), along which the two chimney shells ( 17 ) in the assembled state of the Place chimneys against each other. 15. Casting mold according to claim 13, characterized by protrusions ( 23 ) projecting upwards over the substantially flat surface of the side strips for forming nest-like recesses ( 25 ) for receiving pressure-sensitive adhesive mortar. 16. Casting mold according to claim 15, characterized in that the projections ( 23 ) are evenly distributed in the longitudinal direction of the mold, in particular are arranged in a fixed spacing in such a way that when the chimney half-shells ( 17 ) are stacked together for the finished fireplace, the recesses overlap one another. 17. Casting mold according to claim 15 and 16, characterized,  that the base of the projections adjacent to the side strips as a zylin the jacket is formed. 18. Casting mold according to one of claims 8 to 17, characterized in that the longitudinal racks ( 4 ) with latching recesses on the then effective in the manner of a fixing latch projections ( 12 ) can be placed. 19. Casting mold according to one of claims 8 to 18, characterized in that the longitudinal racks ( 4 ) overlap a tube region projecting beyond the molded bead ( 5 ) by means of a form-fitting recess and can be non-positively fixed to this by inflating the tube ( 6 ).