Multi-shell formed piece and device and process for disposing flexible insulating plates between the walls of said formed piece

Abstract

 In order to achieve effective thermal insulation, a multi-shell formed piece, in particular a pipe (1) for restoring chimneys, having at least two coaxially disposed, spaced-apart walls (2, 3) with a piece of insulating material (4) made of rock wool provided therebetween is, with manufacture and design being simple, configured such that the insulating material (4) consists of at least one bent insulating plate (5) which is preferably made of trock wool and has a largely constant cross section. Further, the invention proposes a device for disposing said insulating plates (5) and a corresponding process.

Description

[0001] The invention addresses a multi-shell formed piece, in particular a pipe for restoring chimneys, said formed piece having at least two coaxially disposed, spaced-apart walls with insulating material provided therebetween. The present invention further addresses a device for providing flexible insulating plates between the coaxially disposed, spaced-apart walls of multi-shell formed pieces. Finally, the invention addresses a process for disposing flexible insulating plates between the walls of multi-shell formed pieces, preferably flue pipes for restoring chimneys, using the device of the invention.

[0002] Multi-shell formed pieces of the kind in question have been known for years in the most various embodiments. Most of them are formed pieces for chimneys. An example is given in German applications DE-OS 19 22 581 and DE-OS 31 39 338.

[0003] The insulating part of the formed piece known from DE-OS 19 22 581 consists of three shell segments forming a pipe-like shell in circumferential direction. Said segments are made of mineral wool and loosely inserted in the circular gap between the walls of the formed piece, with the interior walls or interior pipe being inserted after the pre-assembly of the insulating material. An alternative proposes to firmly attach the insulating material to the outer wall as a pre-made component. However, the shell segments used for insulating are expensive to manufacture and relatively large in size which in turn increases packaging, transportation and storage costs. Moreover, shell segments of this kind often have a thickness tolerance of several millimeteres and, therefore, usually require grinding of the surfaces to a given desired thickness to allow insertion of the segements between the walls of the formed pieces. This procedure further increases manufacturing and assembling costs.

[0004] The formed piece known from DE-OS 31 39 338 is also used to build chimneys, with the gap between the walls of the formed piece being filled with webs of mineral wool. The webs are first loosely fitted to the inner side of the external jacket of the formed piece. At their inner sides, the webs are then covered with thin sheet metal plates, said plates having portions which project over the edges of the formed piece and are bent toward the outsides. Once attached, the sheet metal plates form a type of gap whose opening is slightly larger than the cross section of the inner wall or pipe to be inserted. The so formed sheet metal gap then receives the inner pipe resulting in the compression of the insulating layer. Once the insulting material is inserted, the sheet metal plates are removed so that the insulating material comes in close contact with the walls of the circular gap which it fills.

[0005] However, the above described, known formed pieces per se have various disadvantages. A problem common to all formed pieces of this kind occurs during pre-assembly and insertion of the insulating material. With respect to insulation, the pipe-like shells or segments made of mineral wool have so far been the best possible solution as the direction of the fibers which runs almost transverse to the heat current to be insulated offers a highest possible degree of thermal insulation. The already described financial disadvantages occurring with respect to transporation and storage can, however, not be avoided without loosing the described advantage.

[0006] It is, hence, an object of the invention to further develop and configure a formed piece such that it exhibits good insulation qualities while manufacture and design remain simple. Further, provision shall be made for a suitable device for disposing the insulating material between the coaxially disposed, spaced-apart wall of the multi-shell formed piece of the invention.

[0007] The multi-shell formed piece accomplishes the aforementioned object with the features of claim 1. In said claim 1 the multi-shell formed piece is characterized in that the insulating material consists of at least one bent insulating plate. Said insulating plate has a largely constant cross section and is preferably made of rock wool.

[0008] The invention combines the spatial advantages of insulating plates, i.e. transportation, with the thermal advantages of insulating shells or pipes in that the originally flat plates are bent to assume the shape of a pipe and disposed between the walls of the formed piece to act as insulating material. However, the properties of the insulating plates must be such that they do not break during the bending procedure. This is achieved by selecting an appropriate initial density and laminating a fleece to one side of the plate. Since the insulating plate is bent, the fibers run almost parallel to the surfaces of the walls to be insulated and, hence, transverse to the direction of the heat current. This fact and the largely constant cross section of the insulating plates account for an optimal heat conduction resistance once the unit is fully assembled.

[0009] Such formed pieces are particularly suitable for restoring already existing chimneys, a fact for which there is an increasing demand on the market as more and more boilers with an energy-saving heat output or so called low-temperature boilers are offered. In boilers of this kind, e.g. in floor heating systems, the exhaust gas temperature is below the dew point allowing condensing water to precipitate at the interior walls of chimneys with poor thermal insulation. The wall thus become moist and flue gas exhaustion is impaired.

[0010] With respect to a particularly effective thermal insulation, it is advantageous that the insulating material be configured at least in circumferential direction as one single piece, i.e. one single insulating plate is used in circumferential direction. The dimensions of this insulating plate would have to be such that the edges which run coaxially to the formed piece contact each other to thus form an insulating pipe. In order to ensure proper insulation in the critical contact area, even if only minor dimensional tolerances occur, the contacting edges can be advantageously bevelled such that the portions of insulating material slightly overlap in the contact zone. In this case, the insulating plate may have a trapezoidal cross section. Dimensional tolerances at the edges do, hence, not have any negative effect as the wedge-like edges sufficiently overlap. It is also conceivable to configure the insulating plate as a pipe-like segment having a longitudinal slot. Said slot preferably runs tangentially to the inner wall of the pipe-like segment in order to advantageously account for tolerance differences even in pipe-like segments.

[0011] The thickness of the insulating material or the insulating plate could allow for a some play between the walls of the formed piece and the insulating material. With respect to a particularly high degree of insulating efficiency, it is advantageous if the insulating material is positioned form-fittingly and, if possible, also in a frictional connection, i.e. slightly compressed between the walls of the formed piece. Such a frictional connection between the walls of the formed piece also prevents the insulating material from moving out of position, rather it sits fittingly between the walls.

[0012] In order to make sure that the walls of the formed piece are correctly spaced apart, i.e. coaxial arrangement, already when inserting the insulating material, the walls can be provided with bars or spacers extending therebetween and preferably at the ends thereof. These spacers or bars thus firmly connect the walls to one another ensuring that a fixed distance is maintained throughout. Further, the walls cannot assume their coaxial position until the insulating material is inserted such that the insulating material itself acts as a spacer providing a largely constant distance between the walls. However, the latter possibility involves a higher degree of manufacturing complexity as the walls or pipes must be held in a coaxial arrangement during assembly.

[0013] With respect to the device of the invention for disposing flexible insulating plates between the coaxial, spaced-apart walls of multi-shell formed pieces, particularly formed pieces in accordance with the invention, the aforementioned object is accomplished by the feature of claim 9. According thereto, provision is made for an internal tool to be detachably placed, from the outside or the inside, onto a free end of the respective inner wall of the formed piece, and an external tool to be detachably placed, from the outside or the inside, onto a correspondingly free end of the respective outer wall of the formed piece. When assembled, the internal and the external tool are in a largely coaxial arrangement. In other words, the internal and the external tools of the device of the invention, when assembled, serve as a kind of extension of the walls of the formed piece to be insulated between the walls. Ultimately, this extension allows bending and inserting the insulating plate while receiving the insulating plate in the gap formed therebetween.

[0014] With respect to the structural design of the internal tool when the latter was detachably placed from the inside, onto the free end of the inner wall, it is a particular advantage to provide the outside of the internal tool with an external enlargement or the like preferably running in circumferential direction. Said external enlargement fulfills two functions: it serves as an abutment for stopping the insertion of the internal tool and acts as a transition to the inner wall of the formed piece thus effectively preventing the insulating plate from getting stuck to one of the more or less sharp edges. Having a constant profile, the external enlargement or the like is advantageously dimensioned such that it radially projects from the internal tool by the thickness of the inner wall of the formed piece. Again, the insulating plate is effectively prevented from getting stuck.

[0015] Further, the internal tool also advantageously projects from the area of the external tool in a direction facing away from the formed piece. Accordingly, the projecting portion of internal tool, especially the portion projecting from the area of the subsequently described external tool, serves as a forming aid and, hence, as an abutment to stop the insertion of the insulating plates.

[0016] For a smooth disposal of the insulating plate to be inserted in the gap provided between the walls of the formed piece, the internal tool is provided with a smooth outer surface. The same applies to the inner surface of the external tool.

[0017] Advantageously, the external tool has a funnel-like configuration to actively support the insertion of the insulating plate into the gap between the walls of the formed piece. If the external tool is configured such that it is detachably placed, from the inside, onto the free end of the outer wall, it is particularly advantageous if the wall of the portion of the external tool which expands toward the free end acts as a stop or abutment. This saves the provision of special elements as abutments. If the external tool is configured such that it is detachably placed, from the outside, onto the free end of the outer wall, it is necessary to provide an enlargement directed toward the inside. Said enlargement then serves as an abutment when the tool is placed into position, and also as a transition leading over the free ends of the external wall.

[0018] The end of the external tool facing away from the funnel-like portion advantageously projects, while urging against the outer wall, from the inside into the gap between the outer wall and the inner wall of the formed piece. This portion of the external tool, hence, supports the smooth insertion of the formed piece. The inner wall of this portion is consequently provided with a smooth and even surface.

[0019] The process of the invention for disposing flexible insulating plates between the walls of multi-shell formed pieces in accordance with the invention, especially between the walls of dual-shell pipes, preferably pipes for restoring chimneys, using the device of the invention for disposing such insulating plates is characterized by the features of claim 13. According thereto, the process of the invention comprises the following operational steps:
First, an external tool serving as a guide is detachably placed onto the formed piece. Subsequently, an internal tool serving as an abutment and to bend the insulating plate is detachably placed onto or inserted into the insulating plate. The sequence of placing or inserting the external and internal tools may be freely changed. Both the external and internal tools serve to guide and, if necessary, compress the insulating plates.

[0020] In the next procedural step, the insulating plate to be inserted is bent around the internal tool. Then, the so bent insulating plate is inserted in the gap between the walls of the formed piece. As already mentioned, the internal and external tools serve to guide and, if necessary, to compress the insulating plate when the latter is inserted. In any case, the insulating plate is compressed if it is, in a stress-free state, larger than the gap formed between the walls of the formed piece. Once the one or several insulating plates are inserted, the internal and external tools are removed. A formed piece in accordance with the invention is then completed.

[0021] Finally, as many insulating plates as necessary to completely, i.e. over the entire length of the formed piece, fill the gap between the walls can be advantageously bent and successively inserted using the device of the invention.

[0022] There exist various ways of advantageously configuring and improving the subject matter of the present invention. They are further specified in the attached claims 1, 9, and 13 and in the description of an embodiment of the invention with reference to the drawing. In connection with the explanation of the preferred embodiment with reference to the drawings, the specification also contains generally preferred elaborations and improvements of its teaching. With reference to the drawing

Fig. 1

shows, in a sectional view, a diagrammatic representation of an embodiment of the formed piece of the invention configured as a dual-shell pipe,

Fig. 2

is a diagrammatic representation the subject matter of Fig. 1 with a section taken along line II-II,

Fig. 3

shows, in a side view, a diagrammatic representation the subject matter of Fig. 2 when fully unrolled,

Fig. 4

shows, in a sectional view, a diagrammatic representation the device of the invention for disposing flexible insulating plates between the coaxial, spaced-apart walls of multi-shell formed pieces, i.e. the formed piece shown in Fig 1.

[0023] Fig. 1 shows a dual-shell formed piece, or more strictly speaking a dual-shell pipe 1 in accordance with the invention. Said pipe 1 has two coaxially disposed, spaced-apart walls 2, 3 and a piece of insulating material 4 provided between said walls 2, 3.

[0024] In accordance with the invention, the insulating material 4 consists of insulating plates 5 with a largely constant cross section. In the present example, the insulating plates 5 are made of rock wool.

[0025] The diagrammatic representation of Fig. 2 indicates that the fibers 6 of the rock wool have a preferred direction, i.e. they are uniformly oriented in one direction. The fibers 6 run approximately parallel to the surface of the insulating plate, thus also running approximately parallel to the surfaces of the walls 2, 3 and, hence, transversely to the direction of the heat current indicated by arrows 7 in Fig. 2.

[0026] In the embodiment of Figs. 1 and 2, the insulating material is configured as one single piece running circumferential direction, i.e. one single insulating plate 5 in circumferential direction. Fig. 2 indicates that the axially disposed edges 8 of the insulating plate 5 contact each other. The edges 8 are bevelled to form an acute angle which ensures a slight overlapping of the insulating material 4 in the area of the contacting edges 8 so as to account for dimensional tolerances. Fig. 2 is at the same time a cross section of the pipe-like segment having a slot running almost tangentially to its inner wall.

[0027] Fig. 3 clearly shows that the insulating plate 5, when unrolled, has a trapezoidal cross section in longitudial direction.

[0028] Fig. 1 also shows that at their lower ends the walls 2, 3 are held by bars 9. Said bars 9 extend between the two walls thus connecting them so as to be spaced apart from each other at a foxed distance. Once the insulating material 4 is inserted the walls 2, 3 are further fixed in their positions by said insulating material 4. Thus, even the ends of the walls 2, 3 which do not have a cross-linking bar, i.e. the relative positions of the walls 2, 3, are quasi fixed.

[0029] Finally, with respect to the formed piece or pipe 1 of the invention, emphasis is placed on the fact that the walls 2, 3 of the pipe, i.e. the internal and external pipes, are made of special steel.

[0030] Fig. 4 shows an embodiment of a device in accordance with the invention for disposing the flexible insulating plate 5 between the coaxially disposed, spaced-apart walls 2, 3 of a dual-shell formed piece, i.e. the above discussed dual-shell pipe 1.

[0031] The invention determines that the embodiment of the device in accordance with the invention as shown in Fig. 4 be provided with an internal tool 10 which can be detachably placed, from the inside, onto the free end of the inner wall 2 and, further, an external tool 11 which can be detachably placed, from the inside, onto a free end of the outer wall 3. When placed in position, the internal tool 10 and the external tool 11 are coaxially dispoed to each other and form a kind of extension of the pipe 1 to be filled with insulating plates 5.

[0032] Further, Fig. 4 also shows that the internal tool 10 is provided with a circumferential, external enlargement 12 which, on the one hand, serves as an abutment and, on the other hand, as a transition to the inner wall 2.

[0033] The external enlargement 12 projects from the internal tool 10 by the thickness of the inner wall 2 and forms a transition from the internal tool 10 to the inner wall 2.

[0034] Further, Fig. 4 shows that the internal tool 10 projects form the area of the external tool 11 in a direction facing away from the formed piece or pipe 1. The internal tool 10 with the area projecting from pipe 1, hence, serves as a stop supporting the forming process for the insulating plates 5. Further, the internal tool 10 has a smooth external surface 13 to ensure smooth insertion.

[0035] Fig. 4 also shows that the external tool 11 has an approximately funnel-like configuration. The external tool 11 has an area 14 which expands toward the free end. Said area 14 together with its wall forms a stop for the external tool 11. It is understood that the inner surface 15 of the expanding area 14 of the external tool 11 is also smooth to support the smooth insertion of the insulating plate 5.

[0036] Fig. 4 may also serve to illustrate the process of the invention for disposing flexible insulating plates 5 between the walls 2, 3 of dual-shell pipes 1 using the above discussed device of the invention. First, the internal tool and the external tool 11 are detachably placed onto pipe 1 or between the walls 2, 3 of pipe 1. The internal tool 10 serves as an abutment and to bend the insultaing plates 5 while the external tool 11 acts as a guide.

[0037] The sequence of placing the tool during assembly of the internal tool 10 and external tool 11 is not of importance.

[0038] Together, the internal tool 10 and the external tool 12 serve as guides for the insulating plate 5, and, if ncessary, to compress the latter.

[0039] The insulating plate 5 is bent around the internal tool 10. Subsequently, the so bent insulating plate is inserted into the gap between the walls 2, 3. If necessary, the insulating plate 5 is compressed during its insertion. Once the insulating plate 5 is in its final position, i.e. completeley inserted, the internal tool 10 and the external tool 11 are removed again.

[0040] Figs. 1 and 4 indicate that it is possible to successively insert as many insulating plates 5 as necessary into the gap between the walls 2, 3 until the gap is filled over the entire length of the formed piece. During their insertion into the gap between the walls 2, 3 in longitudinal direction, the insulating plates 5 were subject to compression which further improves thermal insulation.

[0041] The above discussed embodiment serves to provide a better understanding of the teaching of the present application, it does, however, not limit this application thereto.

Claims

1. Multi-shell formed piece, in particular a pipe (1) for restoring chimneys, having at least two coaxially disposed, spaced-apart walls with insulating material (4) being disposed therebetween,
characterized in that the insulating material (4) consists of a bent insulating plate, preferably made of rock wool and having a largely constant cross section.

2. Formed piece in accordance with claim 1, characterized in that the fibers (6) run approximately parallel to the surface of the insulating plate, such that they are also essentially parallel to the surfaces of the walls (2, 3) and, hence, transverse to the heat current (7).

3. Formed piece in accordance with claims 1 or 2, characterized in that at least in circumferential direction, the insulating material (4) is configured as one single piece, i.e. in circumferential direction, it is one single insulating plate (5), in that the axially disposed edges (8) of the insulating plate (5) are in contact one another.

4. Formed piece in accordance with claim 3, characterized in that the edges (8) are bevelled to form an acute angle such that the insulating material (4) overlaps in the area of the contacting edges (8).

5. Formed piece in accordance with claim 4, characterized in that in longitudinal direction, the insulating plate (5) has a trapezoidal cross section.

6. Formed piece in accordance with one of the claims 3 to 5, characterized in that the insulating plate (5) is configured as a pipe-like shell segment with a longitudinal slot preferably running tangentially to the inner wall of the pipe-like shell segment.

7. Formed piece in accordance with one of the claims 1 to 6, characterized in that the insulating material (4) is disposed between the wall in a frictional connection, i.e. slightly compressed.

8. Formed piece in accordance with one of the claims 1 to 7, characterized in that the walls (2, 3) are firmly connected to each other at a fixed distance by means of bars (9) or spacers or the like extending between said walls (2, 3) and preferably at one of the ends thereof.

9. Device for disposing flexible insulating plates (5) between the coaxially disposed, spaced apart walls (2, 3) of multi-shell formed pieces, especially formed pieces in accordance with one of the claims 1 to 8,
characterzized by an internal tool (10) which is detachably placed, from the inside or the outside, onto the free end of the respective inner wall (2), and by an external tool (11) which can be detachably placed, from the inside or the outside, onto the free end of the respective outer wall (3), said internal tool (10) and external (11) being largely coaxially disposed when placed in position.

10. Device in accordance with claim 9, where the internal tool (10) can be detachably placed, from the inside, onto the free end of the inner wall (2), characterized in that the internal tool (10) is provided with a preferably circumferential, external enlargement (12) or the like, which serves as an abutment and as a transition to the inner wall (2).

11. Device in accordance with claim 9 or 10, characterized in that the internal tool (10) projects from the area of the external tool (11) in a direction facing away from the formed piece, in that the portion of the internal tool (10) projecting from the forming part acts as an abutment for the insulating plates (5), which thus supports the forming procedure and is provided with a smooth outer surface (13) to ensure smooth insertion.

12. Device in accordance with one of the claims 9 to 11, characterized in that the external tool (11) has an approximate funnel-like configuration, and in that it can be detachably placed, from the inside, onto the free end of the outer wall (3), and in that the area (14) of the external tool (11), said area (14) expanding toward the free end, acts as a stop or abutment.

13. Process for disposing flexible insulating plates (5) between the walls of multi-shell formed pieces in accordance with one of the claims 1 to 8, particularly between the walls (2, 3) of dual-shell pipes, preferably chimney pipes, using the device in accordance with one of the claims 9 to 12,
characterized by the following procedural steps:

- detachably attaching an external tool (11) which serves as a guide,

- detachably attaching an internal tool (11) which serves as an abutment and to bend the insulating plates (5), whereby both the external and the internal tool (10, 11) can be mounted in the reverse sequence, and serve as guides and, if necessary, to compress the insulating plates (5),

- bending the insulating plate (5) around the internal tool (10)

- inserting the insulating plate (5) bent around the internal tool (10) in the gap between the walls (2, 3) and, if necessary, compressing the insulating plates (5) during insertion,
   removing both the internal tool (10) and the external tool (11)

14. Process in accordance with claim 13, characterized in that bending and inserting covers as many insulating plates (5) as necessary to fill the gap between the walls (2, 3) over entire length of the formed piece, and in that, if necessary, the insulating plates (5) are compressed in longitudinal direction of the formed piece.

Drawing