AU677057B2

AU677057B2 - Twin slab

Info

Publication number: AU677057B2
Application number: AU66535/94A
Authority: AU
Inventors: Ernst Rohringer
Original assignee: Steuler Industriewerke GmbH
Current assignee: Steuler Industriewerke GmbH
Priority date: 1992-12-17
Filing date: 1993-12-16
Publication date: 1997-04-10
Anticipated expiration: 2013-12-16
Also published as: AU6653594A; CN1097231A; EP0673341B1; ATE153624T1; WO1994013560A1; EP0673341A1; TW286336B; DE59306616D1

Abstract

A preferably thermoplastic twin slab, in particular destined to be fastened to a concrete wall, consists of two slabs (1, 3) which are linked together in a liquid-tight manner with anchoring knobs (5) for anchoring to a wall, a leakage gap (2) being formed therebetween. The advantages of the invention are a high stability against outer forces, a low material consumption and a simple and economical production. Also disclosed is a process for producing this twin slab.

Description

PCT/EP 93/03583 STEULER-INDUSTRIEWERKE GMBH, et al.

Twin Plate and Method of Producing It The present invention relates to a large-surface twin plate or slab, in particular a large-surface twin plate made of thermoplastic material. Due to the anchoring knobs provided at its reverse side, this twin plate can in particular suitably be cast into concrete or mortar and can thus be used for protecting concrete structures against corrosion.

Between the plates is a continuous leakage gap which has a defined width and is sealed on both ends.

The authorities increasingly demand that concrete containers for storing liquids which would contaminate water be provided with linings in the form of tightly sealing and resistant twin-plate constructions having an intermediate leakage gap. These linings have to consist of two resistant sealing plates which are separated by a monitoring space, the leakage gap.

From EP-A-0 059 929, it is known to weld a multitude of anchors onto the reverse side of a thermoplastic plate, the plate being a single plate which is also destined to be used as a lining for protecting concrete structures.

DE-A-38 30 439 discloses a method of producing a leakage gap between two independent plates. According to this method, the leakage gap is formed between a tightly sealing plate facing the loaded side and a plate behind the first plate, which is separated from the first plate by the leakage gap and is perforated but not densely provided with holes. Thus, the leakage gap is not enclosed by two tightly sealing thermoplastic plates so that a liquid seeping into the leakage gap can get into contact with the concrete. Due to this leakage, one cannot speak of two sealing plates.

Moreover, from German Patent Application P 41 35 641.1, a method is known according to which two single plates are joined to form a twin plate, wherein the anchors to be cast into the concrete are displaced with respect to spacers serving for joining the two plates. According to this method, spacers and anchors have to be welded onto the plates in two separate steps, and in a third step the two plates are then joined via the spacers. Due to the displacement of the anchors with respect to the spacers, the anchoring forces have to be transmitted via the rear plate with a lateral displacement into the spacers attached to the front plate. For taking up these transmitted forces, the rear plate must have the respective thickness, which would otherwise, for its actual purpose, i.e. the formation of a tightly sealed leakage gap, not be necessary.

In contrast, it is an object of the present invention to provide a twin plate, in particular a twin plate made of thermoplastic material, which has a tightly sealed leakage gap and a high stability against external force- despite a low material consumption and whose production is simple and non-expensive.

This object is achieved by the features of the claims.

For achieving this object, the invention is based on the following idea.

A non-perforated thermoplastic front plate which faces the loaded side is sealingly and positively connected with a perforated thermoplastic rear plate via a multitude of thermoplastic anchoring knobs projecting through the perforated plate, an intermediate gap being maintained. When the twin plate is built in, the portions of the anchoring knobs projecting out of the twin plate are cast into concrete or mortar. The two thermoplastic plates are joined to form a ,win plate such that each of the two parts of the joined thermoplastic plates forms an individual sealing layer.

It is a fundamental advantage of the invention that the anchor knobs, which are cast into concrete for mechanically anchoring the twin plate, transmit the forces acting upon the twin plate into the ground rectilinearly and thus in a way favourable in terms of statics. Thus, the rear plate does not have to transmit or divert forces and can, according to its purpose, be thin.

A further advantage of the invention is the economical production method which permits the production of the twin plate in one single operation.

The twin plates known so far exhibit a high rigidity due to the front plate and the rear plate which is spaced from the front plate by the leakage gap; in some fields of application, this leads to problems during the assembly at the building site. This rigidity can be reduced by providing the possibility of diffeiential elongation rates between the front and the rear plates. Due to the specific conneztion between the rear plate and the anchoring knobs, the present invention provides this possibility of elongation.

The invention will be illustrated in the following by means of the drawings, in which: Figures 1 to 4 show cross-sections of different embodiments of the invention.

According to Fig. 1, a front plate 1 facing the loaded side is welded onto a second rear plate 3 facing a concrete side by means of anchoring knobs 5. At the joints with the anchoring knobs, the rear plate 3 is provided with depressions 4, and the cylindrical ends 5b of the anchoring knobs 5 project through the openings 7 of the depressions 4.

When welding the anchoring knobs 5, their portions 5b are joined with the plate 1 and simultaneously a disk or a diskor flange-like broadening 5a of the anchoring knobs 5 is joined with the indented part 4 of the plate 3 sealingly and positively at joints 6b and/or 6a by means of friction welding. Between the two plates 1 and 3, a leakage gap 2 is provided whose width is defined by the depressions 4. The conical or otherwise shaped portion 5c of the anchoring knobs 5, which projects out of the plate 3, serves for anchoring the twin plate by casting the anchoring knobs into unset concrete or mortar. The size and the shape as well as the number of anchoring knobs per m 2 depend on the prerequisites for uniformly anchoring the linings protecting against leakage and consisting of twin plates under assembly and service conditions. The weldings are preferably produced by friction welding, e.g. vibration or spin wlding.

According to Fig. 2, the two plates 1 and 3 are linked by means of anchoring knobs 5 in such a way that the disks of the anchoring knobs 5 are welded onto the plate 1 via joint 6b by means of friction welding and, simultaneously, the plate 3 is welded onto the top surface of the disk at joint 6a. The anchoring knob 5 projects out of the opening 7 in the plate 3 and later serves as a mechanical anchoring means in concrete or mortar. The width of the leakage gap 2 is determined by the height of the disk 5a. The simultaneous welding at the joints 6a and 6b is, for example, achieved by spin welding the anchoring knobs 5. By means of a joining pressure acting on the anchoring knob 5 on the one hand and on the area of the plate 3 above the joint 6a on the other hand, a simultaneous joining at the joints 6a and 6b is achieved during spin welding. However, the anchoring knobs can also be welded onto plate 1 first via a specific welding technique and then, in a second step, the disk 5a of the anchoring knob 5 is sealingly and positively welded onto the rear plate 3 via joint 6a using another welding technique.

According to Fig. 3, in a further embodiment, plate 1 is joined with plate 3 by spin welding the anchoring knobs projecting through the opening 7. By shaping a depression in the plate 3 correspondingly, a simultaneous welding at joints 6a and 6b is achieved when spinning the anchoring knobs 5. The width of the leakage gap 2 is determined by the depth of the depression 10. By means of an annular joint 9 arranged at the level of the plate 3 subsequently and circumferentially to the anchoring knob 5, the plate 3 can slightly expand relative to the position of the anchoring knob 5 and thus reduce the rigidity of the twin plate during the assembly.

According to a preferred method, the twin plate is produced by friction welding. However, other welding techniques, such as heated-tool or ultrasonic welding, can also be applied.

Moreover, the plates 1 and 3 can also be joined with the anchoring knobs 5 by bonding.

According to Fig. 4 of the present invention, the leakage gap 2 of the twin plate can also be divided into several sections, which are sealed with respect to each other in a liquid-tight manner, by the sealing strips 12. These sections can be provided with discharge and aeration means 13 and 14, respectively, which project outside through the plate 1 and the concrete wall 11 and by means of which the tightness of each individual section of the twin plate can be examined. Thus, a leak can preferably exactly be localised, which simplifies the repair of a possibly damaged twin plate. The sealing strips 12 can be welded in between the plates 1 and 3. Several twin plates can be joined to form a system, in particular a container. Preferably, in a container, the discharge means 13 are provided at the lower end of the section and the aeration means 14 at the upper end of the section such that the leakage liquid can be discharged to the bottom.

0 Liq

Claims

1. A twin plate comprising a first plat- and a second plate which form a sealed leakage gap (2) thereinhetween and several anchoring knobs which are joined with one end with the twin plate, characterised in that the anchoring knobs project through the second plate adjacent to the free ends of the anchoring knobs and are connected with both plates (1 and 3) in a liquid-tight manner.

2. The twin plate according to claim i, characterised in that the plates (1 and 3) and/or the anchoring knobs consist of thermoplastic material.

3. The twin plate according to claim 1 or 2, characterised in that a) the second plate comprises depressions (4) directed towards the first plate and having openings for the anchoring knobs b) the connecting ends (5b) of the anchoring knobs project through the opening and are connected with the first plate c) the anchoring knobs comprise a disk-shaped broadening (5a) between their connecting ends and their free ends said disk-shaped broadening (5a) being connected to the depressions such that it rests on them; and d) the depth of the depression determines the width of the leakage gap

4. The twin plate according to claim 1 or 2, characterised in that a) the second plate is provided with openings (7) for the anchoring knobs b) the anchoring knobs are provided with a disk- shaped broadening (5a) as a joining means which laterally projects under the second plate and c) the second plate and the first plate are joined by means of the broadening (5a) whose thickness determines the width of the leakage gap (2) The twin'plate according to claim 1 or 2, characterised in that a) the second plate.(3) comprises depressions S ompise directed towards thekplate and having openings for the anchoring knobs b) the anchoring knobs are connected laterally with the second plate and via their connecting ends (5b) with the first plate and c) the depth of the depression (10) determines the width of the leakage gap (2)

6. The twin plate according to claim 5, characterised in that at the level of the second plate annular grooves are provided and arranged around the circumference of the anchoring knobs

7. The twin plate according to any of claims 2 to 6, characterised in that the anchoring knobs are joined with the plates (1 and 3) by friction welding.

8. The twin plate according to any of claims 2 to 6, characterised in that the anchoring knobs are joined with the plates (1 and 3) by means of a heated- tool or ultrasonic welding.

9. The twin plate according to any of claims 1 to 6, characterised in that the anchoring knobs are joined with the plates (1 and 3) by bonding. I I- The twin plate according to any of claims 1 to 9, characterised in that the anchoring knobs are connected with the plates and 1) via joints (6a and 6b, respectively)

11. A twin plate -i inRti-"4- according to any of claims 1 to 10, characterised in that the leakage gap is divided into several sections, which are sealed with respect to each other in a liquid-tight manner, via sealing strips (12) between the first plate and the second plate (3)

12. The twin plate according to claim 11, characterised in that the sections are provided with discharge and aeration means (13 and 14, respectively) so that tightness of the individual sections of the twin plate or a system of twin plates can be examined.

13. The twin plate according to any of claims 11 or 12, characterised in that the sealing strips (12) are welded in between the first plate and the second plate (3)

14. A container consisting of several twin plates according to any of claims 11 to 13. A method of producing a' twin plate according to any of claims 1 to 14, characterised in that the anchoring knobs are joined with the plates (1 and 3) in a single step.

16. A method of producing a twin plate according to any of claims 1 to 14, characterised in that the anchoring knobs are joined with the plates (1 and 3) in two separate steps. Abstract Twin Plate and Method of Producing It A preferably thermoplastic twin plate, in particular destined to be fastened at a concrete wall, and a method of producing it tare provided. The twin plate consists of two plates which are linked by anchoring knobs in a liquid-tight manner for being anchored in wall, a leakage gap being formed between these plates. The advantages of the present invention are a high stability against external forces despite a low consumption of material and a simple and non- expensive producibility. I