WO1994012735A1

WO1994012735A1 - Liquid-tight coupling for interconnected plastic webs forming a sealing wall

Info

Publication number: WO1994012735A1
Application number: PCT/EP1993/003343
Authority: WO
Inventors: Andreas Rödel
Original assignee: Progeo Geotechnologiegesellschaft Mbh
Priority date: 1992-11-30
Filing date: 1993-11-29
Publication date: 1994-06-09
Also published as: DE4311948A1; EP0670937A1

Abstract

A liquid-tight coupling for plastic webs to be interconnected in order to form a sealing wall has an inner part (1) and an outer part (2) constituted by a positive and a negative profile. The outer part is designed as a cable profile and forms an inner chamber between its branches for receiving a sealing zone, in particular a heat-sealable zone. Before both coupling parts are assembled, this inner chamber is closed by an easily severable link arranged at the ends of the branches to protect the sealing zone from dirt. This link is only opened when the inner part is threaded into the outer part. In the inner chamber of the outer part (1), which in the assembled state of the coupling parts (1, 2) is outwardly closed by seals, in particular labyrinth seals, is provided at least one heat-sealable sealing zone (15a*, 15b*) which may be activated by at least one heating element (16a, 16b) controllable from the outside and arranged in the proximity of said sealing zone.

Description

Liquid-tight lock for interconnected plastic sheets forming a sealing wall

The invention relates to a liquid-tight lock for interconnected, forming a sealing wall plastic sheets, which consists of arranged on adjacent edges of the plastic sheets, a castle inner and a outer part forming profiles, which interlock in the installed state and are tightly welded together.

Sealing walls consisting of plastic webs connected to one another via a liquid-tight lock are used to seal off spaces filled with masses, such as soil or the like. A main area of application is the encapsulation of contaminated rooms. In order to encapsulate such spaces, slots are first sunk, the slots filled with a cement suspension and finally the plastic sheets are introduced into this suspension one after the other. In this case, a plastic web to be inserted is threaded with its lock inner part into the lock outer part of the plastic web already introduced.

The main requirements for locks for interconnected plastic sheets of sealing walls are light Installation, high tightness, possibility of checking for leaks and the possibility of subsequently sealing leaks. Known locks only partially meet these requirements.

In a known lock of the type mentioned, the outer and inner parts of the lock consist of slotted tubular profiles which are welded together. A prerequisite for a tight weld is that the parts to be welded together are not dirty. This requirement cannot be met in the prior art if the assembly of the two lock parts has to take place in a slot filled with a liquid, in particular a cement emulsion.

The invention has for its object to provide optimal conditions for the welded joint on a lock to be assembled of the type mentioned.

This object is achieved in that the lock outer part is designed as a fork profile and forms an interior between its fork branches for receiving at least one sealing zone, which is closed before assembly of the two lock parts by an easily separable connection provided at the tips of the fork branches.

Since the interior of the lock according to the invention is closed before assembly, the sealing zone is protected against contamination. The connection is only opened when the inner part of the lock is threaded into the outer part of the lock, so that the sealing zone is protected against contamination which may occur in the meantime. This protection is particularly important when the two parts in the sealing zone are to be welded or glued together. The connection at the tips of the two fork branches can be implemented in various ways, for example as a clamping connection formed due to the pretensioning of the fork branches or as a weld seam or as a sealing tab. In any case, the connection is only separated when the inner part of the lock is threaded in, so that protection against contamination is ensured.

The lock outer part can be closed at one end, namely the lower end inserted into the slot, in particular the lock can consist of a cap. This configuration is particularly important when the lock outer part is in one with e.g. Liquid filled slot is located.

In order to prevent the penetration of liquid into the lock outer part when threading the lock inner part, a clamp that surrounds the fork branches and sits with a slot and sealing wedge in the gusset between the fork branches can be slidably arranged through the lock inner part according to a further embodiment of the invention his. In this case, the clamp leads the inner part of the lock when it is drawn in and opens the connection arranged at the tips of the outer part of the lock. The slot and sealing wedge progressively closes the gusset as it is being threaded in and prevents liquid from getting into the outer part of the lock. This can alternatively or be supported in that a channel which can be charged with a gaseous medium is arranged in the outer part of the castle. This channel fills the outer part of the lock, so that gaseous medium bubbling out in the gusset prevents liquid from getting into the outer part of the lock.

The weldable sealing zone can be realized in different ways. It is preferably a heat-sealable sealing zone which is separated by at least one their proximity arranged, externally controllable heating element can be activated.

The use of a heat sealable sealing zone results in an optimal liquid-tight seal. As will be explained in more detail below with special configurations, such a seal can also be easily monitored for errors and repaired.

According to one embodiment of the invention, the heating element extends over the entire surface of the sealing zone. The heating element is preferably designed as an electrical resistance heating conductor. Various heating conductors are suitable for this, in particular one is

Resistance heating conductor made of graphite or conductive carbon black is suitable because it is not susceptible to corrosion. Such a

Resistance heating conductors can be melted in the form of fibers into the surface of the parts forming the sealing zone or can be produced by filling the thermoplastic synthetic material forming the diaphragm wall lock entirely or in the region of the zone to be welded with conductive carbon black and thereby making it conductive. Electrical energy can be supplied to heat the resistance heating conductor in various ways.

When using a thermoplastic plastic made conductive by adding conductive carbon black as a resistance heating conductor, the electrical energy can be supplied to the welding zone via two electrodes running parallel to one another, which are embedded in the conductive plastic of the zone to be welded or are pressed onto the zone to be welded .

The fibers of the resistance heating conductor are preferably connected with their ends to two supply lines arranged at a distance from one another along the edges of the sealing zone. By When a voltage is applied, the resistance heating conductor is heated either simultaneously over its entire length or in the form of a wandering welding zone, in that the voltage is gradually controlled at a specific ratio between the lead resistance and the resistance heating conductor. If the voltage is gradually increased, the fibers of the resistance heating conductor are first raised to the welding temperature in the initial area and then destroyed. This type of heating and destruction, combined with welding in the welding zone, progresses gradually until the end of the welding zone. The migrating welding zone has the advantage over the simultaneous welding over the entire length of the welding zone that the connected load of the connecting lines can be kept low. Of course, it is also possible with the first alternative to destroy the fibers by overcurrent at the end of the welding. If the fibers are destroyed at the end, then the two connecting lines, which are preferably located in test channels, are no longer conductively connected to one another, so that if there is a leak in the weld seam, moisture bridges the connecting lines. This bridging can then be interpreted as a sign of a defective weld.

As an alternative to a resistance heating conductor, the heat-sealable sealing zone can also be activated in such a way that a heated gaseous or liquid medium flows through a channel. The channel or channels are preferably formed in the inner lock part adjacent to the welding zone. If the channel or channels is arranged upstream or downstream of the sealing zone, it can be filled with a sealing compound in the event of a leak in the seal in order to seal the leak.

According to a further embodiment of the invention, the sealing zone is in each case on the two inner sides of branches of a fork-shaped extension of a profile lying in the interior of the castle and the outer sides of a plug-in extension of the seat between these branches other profiles. This provides double security against leaks.

In order to achieve a full-surface seal when welding, the sealing zone should be parallel to the sealing wall. In this case, the hydrostatic pressure of the suspension surrounding the sealing wall is used to press the sealing surfaces against each other.

As already explained in connection with the resistance heating conductor, a pair of lines can be used as the moisture sensor, which is accommodated in a channel on each side of the sealing zone.

In order to check the sealing zone for leaks, it can be sufficient according to one embodiment of the invention if a moisture sensor is located on at least one side of the heat-sealable sealing zone. In order to accommodate this moisture sensor on the one hand and to enable the repair of leaks by introducing a sealing compound on the other hand, a channel can be arranged on at least one side of the heat-sealable sealing compound.

For even better sealing, a labyrinth seal can be provided on both sides of each heat-sealable zone. The labyrinth seal can form the positive connection of the outer and inner parts of the lock. The labyrinth seal is preferably formed on the fork branches of the lock outer part designed as a fork profile and of the lock inner part located in between. In order to create the largest possible sealing surfaces, the outer and inner parts of the lock can be designed as positive and negative profiles. The hydrostatic pressure that acts on the lock supports the sealing effect. The invention is explained in more detail below with reference to a drawing which represents an exemplary embodiment. In detail show:

Figure 1 is a lock for connectable

Sealing membranes in perspective during assembly,

FIG. 2 shows the lock according to FIG. 1 in cross section,

3 shows the lock with the outer and inner parts of the lock before assembly,

Figure 2 * and 3 * a lock in an embodiment modified from Figure 1 to 3 in the representation of Figures 2 and 3 and

2 ** shows a lock in an embodiment modified from FIGS. 1 to 3 * in the illustration in FIG. 2.

The lock shown in Figure 1 during assembly consists of a positive and a negative profile made of plastic, which form a lock outer part 1 and a lock inner part 2. Each lock part 1, 2 carries a welding tab 3, 4 for plastic sealing sheets, not shown in the drawing. The lock outer part 1 is closed at its lower end shown in the drawing by a cap 5. When threading the inner lock part 2 into the outer lock part 1, the inner lock part 1 pushes a lost clamp 6 in front of it, which on the one hand engages around the outer lock part 1 and on the other hand has a slot and sealing wedge (not shown in the drawing) in the gusset of the outer lock part 1.

As can be seen above all from Figures 2 and 3, the lock has a flat oval cross section and is for The mid-plane is mirror-symmetrical. The castle outer part

1 is designed as a fork profile. His two fork branches 7a,

7b enclose an interior 8, which in the not yet assembled state of the lock by a to the

Tips of the fork branches 7a, 7b arranged seal 9 is closed. In the middle of the interior 8 is a web

10 arranged, the channels 11a on both sides of its base point,

11b. Behind these channels 11a, 11b is another one

Cross section of larger channel 12.

The front section 7a *, 7b * adjoining the tips of the fork branches 7a, 7b forms part of a labyrinth seal.

If the lock outer part 1 forms the positive profile of the lock, the lock inner part 2 forms the associated negative profile. Thus, in the assembled state, the sections 7a *, 7b * of the fork branches 7a, 7b lie between fork branches 14a, 14 and a connecting part 13. The sections 7a *, 7b *, the fork branches 14a, 14b and the connecting part 13 form the aforementioned labyrinth seal 7a * *, 7b **, 13a, 13b and at the same time a positive locking, which is able to absorb tensile and compressive stresses in the central plane of the lock with various hook-shaped interlocking elements.

The connecting part 13 carries a fork-shaped extension 15, the fork branches 15a, 15b enclosing the web 10. The inner sides 15a *, 15b * of the fork branches 15a, 15b and the outer sides 10a, 10b of the web 10 form heat-sealable sealing zones. In order to be able to heat this sealing zone, an electrical resistance heating conductor 16a, 16b is embedded in the fork branches 15a, 15b and is distributed over the entire surface. The resistance heating conductors 16a, 16b consist, as indicated in FIG. 2, 2 *, of a comparatively thin one sheet material, in particular made of carbon fibers, in particular in the form of a fleece or fabric, which is connected at its two longitudinal edges to electrical leads, not specified. As already mentioned, the resistance heating conductors can be formed from thermoplastic made conductive by conductive carbon black. At the foot of the fork branches 15a, 15b, a channel 17 is arranged, in which, as in the channels 11a, 11b, a moisture sensor 18, 19a, 19b is accommodated.

The lock is assembled in the following way:

Before the inner lock part 2 is threaded from above into the outer lock part 1, a gaseous medium is introduced into the channel 12 and the inner space 8 is introduced under a slight overpressure in relation to the external pressure of the suspension surrounding the outer lock part 1. So that this medium can get into the interior 8, a bridge 5a to one of the channels 19a and thus to the entire interior 8 is produced in the cap 5 closing the lower end of the outer lock part 1. After the retaining clip 6 is placed on the lock outer part 1, which surrounds the sections 7a *, 7b * of the fork branches 7a, 7b on the outside and with its slot and sealing wedge, not shown in the drawing, the gusset between the insides of the tips of the fork branches 7a, 7b closes, the inner part 2 is threaded. It pushes the clamp 6 in front of it, which slits open the seal 9 in accordance with the progress of the feed. Small leaks in the area of the slot and sealing wedge do not allow any liquid to get into the interior 8, because the gaseous medium, which is under slight internal pressure, prevents penetration. In the slit area, the labyrinth seal 7a **, 7b **, 13a, 13b prevents liquid from penetrating.

After the two lock parts 1 and 2 have reached their end position have, current is conducted into the heating conductors 16a, 16b and the welding of the sealing zone is effected.

In the exemplary embodiment in FIGS. 2 and 3, the supply of electrical energy can take place via the embedded supply lines, which are arranged at the ends of the fibers or in the region of the conductive thermoplastic, and are not specified in any more detail. In the exemplary embodiment in FIGS. 2 and 3, the electrical energy is supplied through the lines 18, 19a, 19b, which are exposed in the channels 11a, 11b, 17 and form the moisture sensors. In the exemplary embodiment in FIGS. 2 *, 3 *, the heating conductors 16a, 16b are destroyed after the welding zone has been welded by overcurrent.

The exemplary embodiment of FIGS. 2 * and 3 * differs from that of FIGS. 2 and 3 only in that the heating conductors 16a, 16b are connected at their edges to electrical lines serving as moisture sensors 18, 19a, 19b. The electrical connection between these lines via the resistance heating conductors 16a, 16b is interrupted at the end of the welding by overcurrent, which destroys the heating conductors 16a, 16b.

The embodiment of Figure 2 ** differs from that of the previous figures in that instead of electrical resistance heating conductors 16a, 16b in the fork branches 15a, 15b channels 15a *, 15b * are arranged for a liquid or gaseous heating medium.

Any leaks can be determined by means of the moisture sensors 18, 19a, 19b, which are arranged in front of and behind the sealing zones 10a, 10b, 15a *, 15b *. If a leak is found, it can be remedied by introducing a sealant into the channels 11a, 11b, 17. In order to also be able to visually check the welding zone, an endoscope can be guided, for example, through the test anal 17 in the exemplary embodiment in FIG. 3. If two PE surfaces are welded together, with sufficient plasticization of the welding zone and sufficient joining pressure at the edge of the seam, a bead of PE is formed, the shape of which allows conclusions to be drawn about the quality of the weld. The visual control of the welding zone can also be used during the welding process with a migrating welding zone. It is also possible to test the weld seams by applying pressure to the test channels individually or in groups and by using the pressure drop as a function of time as a test variable. ^"It is also possible to check the weld seam with the aid of the pulse measurement method, in which a measurement signal is obtained by high-frequency pulses on one or both of the coupling electrodes, which can be evaluated as a measure of the quality of the weld seam with regard to the homogeneity of the plastic surrounding the electrodes .

Claims

Expectations

1. Liquid-tight lock for interconnected, a sealing wall forming plastic webs, which consists of arranged on adjacent edges of the plastic webs, a lock inner (2) and outer lock part (1) forming profiles, which interlock positively when installed and are tightly connected to each other, characterized that the lock outer part (1) is designed as a fork profile and between its fork branches (7a, 7b) forms an interior (8) for receiving at least one sealing zone (10a, 10b, 15a *, 15b *), which before the assembly of the two lock parts (1, 2) is closed by an easily separable connection (9) provided at the tips of the fork branches (7a, 7b).

2. Lock according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the lock outer part (1) is closed at one end.

3. Lock according to claim 2, d a d u r c h g e k e n n z e i c h n e t that the closure consists of a cap (5).

4. Lock according to one of claims 1 to 3, characterized in that in the Lock outer part (1) a channel (12) which can be filled with gaseous medium is arranged, via which the interior (8) of the lock outer part (1) can be filled.

5. Lock according to one of claims 1 to 4, characterized in that on the lock outer part (1) a fork branches (7a, 7b) encompassing bracket (6) with a slot and sealing wedge in the gusset between the fork branches (7a, 7b ) sits, through the lock inner part (2) is slidably arranged.

6. A liquid-tight lock according to one of claims 1 to 5, characterized in that the weldable sealing zone (10a, 10b, 15a *, 15b *) is heat-sealable and can be activated by at least one heating element (16a, 16b) arranged in its vicinity and controllable from the outside is.

7. Lock according to claim 6, so that the heating element (16a, 16b) extends over the entire surface of the sealing zone (10a, 10b, 15a *, 15b *).

8. Lock according to claim 6 or 7, so that the heating element (16a, 16b) is designed as an electrical resistance heating conductor.

9. Lock according to claim 8, d a d u r c h g e k e n n z e i c h n e t that the resistance heating conductor (16a, 16b) consists of graphite.

10. Lock according to claim 8, characterized in that the resistance heating conductor consists in particular of conductive carbon black, thermoplastic material.

11. Lock according to claim 6 or 7, that the heating element is designed as a channel that can be charged with a gaseous or liquid medium.

12. Lock according to one of claims 6 to 11, characterized in that the sealing zone (10a, 10b, 15a *, 15b *) each on the two inner sides of branches (15a, 15b) of a fork-shaped extension lying inside (8) of the lock (15) of one profile (2) and the outer sides of a web-shaped extension (10) of the other profile (1) which is seated between these branches (15a, 15b).

13. Lock according to one of claims 6 to 12, so that the sealing zone (10a, 10b, 15a *, 15b *) is parallel to the sealing wall.

14. Lock according to one of claims 6 to 13, so that a moisture sensor (18, 19a, 19b) lies on at least one side of the heat-sealable sealing zone (10a, 10b, 15a *, 15b *).

15. Lock according to one of claims 6 to 14, d a d u r c h g e k e n n z e i c h n e t that a channel (11a, 11b, 17) is arranged on at least one side of the heat-sealable sealing zone (10a, 10b, 15a *, 15b *).

16. Lock according to one of claims 1 to 15, so that a labyrinth seal (7a **, 7b **, 13a, 13b) is provided on both sides of the heat-sealable zone.

17. Lock according to claim 16, characterized characterized in that the labyrinth seal (7a **, 7b **, 13a, 13b) forms the positive connection of the outer (1) and inner part (2) of the lock.

18. Lock according to claim 16 or 17, characterized in that the labyrinth seal (7a **, 7b **, 13a, 13b) on the fork branches (7a, 7b) of the lock outer part designed as a fork profile (1) and the intermediate lock inner part (2) is trained.

19. Lock according to one of claims 1 to 18, d a d-u r c h g e k e n n z e i c h n e t that the lock outer (1) and lock inner part (2) are designed as positive and negative profile.