DE19950466C2 - Leak protection lining for tanks and method for equipping tanks with a leak protection lining - Google Patents

Abstract

The invention relates to a leak-resistant lining for tanks used for the storage of water contaminating substances. The invention further relates to a method for equipping tanks with a leak-resistant lining. The aim of the invention is to overcome the disadvantages of the known state of the art and produce a leak-resistant coating which is suitable for universal tanks of all construction types, in particular, those with fittings near the tank-floor, which can be simply assembled and guarantees a reliable leak-control system in the tank flooring and tank walls. A solution is disclosed, whereby an angled fixing bracket (4) is fitted in position around the edge between the tank wall (1) and the tank floor (2), which comprises two faces (4a, 4b), running parallel to the tank wall (1) and the tank floor (2) respectively. The face (4a), running parallel to the tank wall (1), has a joint with the tank wall (1) which is resistant to the contained substance. A cavity (7) exists between the angled fixing bracket (4) and the adjacent sections of the tank wall and tank floor. Said cavity (7) is suitable for leak control. The film or sheet (5) laying on the insert (3) which defines the cavity is fixed in a substance-resistant manner to that face (4b) of the angled fixing bracket (4) parallel to the tank floor (2).

Description

The invention relates to a leak protection lining for tanks for storing water hazardous media, using flexible plastic films, as well as a Process for equipping tanks with a leak protection lining.

Flat-bottom tanks are made of steel or reinforced concrete and are mainly used for Storage of fuels, mineral oils, acids, alkalis, solvents or the like. used.

In practice, both single-walled and double-walled flat-bottom tanks are in the Commitment. For environmental reasons there is a need to monitor the Flat bottom tanks for leaks. To make this possible, it is single-walled Storage tanks required, this with an additional leak protection lining retrofit. Is known for. B. also, an additional intermediate floor made of metal weld and evacuate the resulting chamber or on an under To maintain atmospheric pressure by monitoring the pressure detect leaks occurring at an early stage.

EP 0 705 771 A1 describes a method for producing a double-walled tank described from a single-walled tank. Be in the tank wall Flat profiles welded on and sheets welded onto the flat profiles.

It is known from EP 0 069 303 B1 for existing single-wall buried Leak control tanks, a bubble wrap and an inner plastic cover to monitor between the tank wall and the bearing groove to form a clear intermediate space. Since a plastic film is not electrically conductive, also proposed to arrange a metal foil as a spacer on which one electrically conductive fiber-reinforced epoxy layer is sprayed on.

The use of an electrically conductive polyurethane film for the production of Flexible inlays for containers are described in EP 0 571 868 A1.

The aforementioned linings are very expensive to manufacture and assemble. Intermediate or additional floors have so far been made exclusively of metal and attached by welding inside the tank.

As far as is known, the use of flexible plastic films is always the entire interior of the tank lined with a so-called second wall. Out  DE 196 21 469 A1 is an interior consisting of a double-sided film lining known for a petrol tank. The foil is in the dome of the tank by means of a clamping ring held.

A lining of the entire interior of a tank to form a double However, wall is very expensive.

From practice it is known that the connection of the film to the tank wall Difficulties arise because the connection points are media and vacuum tight have to. In the case of steel storage tanks in particular, it must also be taken into account that they are outdoors and are exposed to considerable temperature fluctuations. In addition, changing liquid levels in the containers also have an effect the expansion behavior of the container material.

DE 298 07 285 U1 discloses a flat-bottom tank with a leak protection lining, that of at least one pressure-stable, cavity-forming insert and one on media-resistant film on this insert is made of plastic. The foil covers the bottom of the tank and extends to the bottom of the inside the tank wall and is at a short distance from the tank bottom Fastened all around by means of a clamping device. The insert covered the existing tank floor and extends at most to below the clamp contraption. The clamping device is preferably at a distance of 100 to 500 mm to the tank bottom. The clamping device consists of the same Height arranged, in or on the tank wall at defined intervals attached, inwardly projecting bolts on which the clamping rails can be attached. Each between the clamping rails and the film as well as the film and the Elastic sealing tapes are arranged all around the inside of the tank wall. The clamping rails are locked under pressure on the bolts.

The retrofitting of tanks in which the tank wall and the tank bottom in one right or different angles to each other, with a flexible leak protective lining that extends up to a certain height on the inside of the tank Wall extends, is very expensive, especially in the assembly of the film. in the Attention must be paid to the corner area between the tank wall and the tank bottom be that the flexible film system is wrinkle-free. The required sweat Seams must be carried out in such a way that the desired weld seam strength is achieved all connection points is reached. This is with a lot of manual effort connected and often requires additional rework.

There are also tanks, preferably in the chemical industry, in which agitators are arranged to constantly circulate the liquid to be stored. Certain Tanks have a bottom that is strongly inclined towards the center with a central one there arranged spout. Due to the flow movement towards the center  The film becomes liquid from the transition area wall / floor to the center of the container moves, causing inadmissible tensions in the film in this area is coming. The stirring movements, especially with low liquid stand in the tank, the film "fluttered", which increases the risk of The film is torn off. The same danger to the film system exists with necessary cleaning processes if there is sludge on the floor must be removed.

Another problem is that tanks used in the petroleum industry in lower area of the tank wall pipelines for the discharge of the above Have a layer of water separating the tank bottom. The lining of such tanks with a flexible film system that attaches to the tank wall is extreme complicated and very complex.

The invention has for its object a leak protection lining system for Create tanks using flexible films that are suitable for universal tanks of different types, especially those with ground level Built-in, is suitable, requires little installation effort and one Reliable leak protection monitoring in the area of the tank bottom and the Tank wall guaranteed. A suitable method for equipping Tanks can be created with a leak protection lining.

According to the invention the object is achieved by the features specified in claim 1 solved. Suitable design variants are the subject of claims 2 to 13. A procedure for equipping a tank with a leak protection lining and a leakage monitoring device is specified in claim 14. Further Comments on the proposed method are in claims 15 to 19 specified.

The leak protection lining consists of a in the corner area of the tank, between the Tank wall and the tank mounting arranged circumferential mounting bracket with one each running parallel to the tank wall and the tank bottom Leg. The leg running parallel to the tank wall is stable and connected to the tank wall in a media-tight manner. The mounting bracket is in its location so fixed that between this and the neighboring areas of A suitable cavity for leakage surveillance is formed. The cavity-forming insert in the area of the tank bottom either completely covers the entire tank bottom or only the area that is limited by the circumferential bottom leg. The on the cavity forming insert, media-resistant film or sheet overlaps the  bottom leg of the mounting bracket and is media-tight with this connected. Depending on the size of the access opening for the tank the mounting bracket from a prefabricated component or from several Individual parts that are media-tight as part of the assembly of the leak protection lining be connected to a circumferential mounting bracket. In the tank bottom and / or in the tank wall are more conventional for leakage monitoring Design arranged. With regard to the design of the mounting bracket and There are different ways of attaching the film or sheet, to which will be discussed in more detail in the examples given.

The proposed leak protection lining leads in comparison to the previous ones known and applied solutions for a variety of advantages. The critical area of tanks for the storage of chemical products is the Transition area tank wall / tank bottom, which in general terms possible leakages must be monitored. The arrangement of a spaced circumferential mounting bracket in this area creates the one hand required cavity for effective leakage monitoring and enables on the other hand, a tension-free fixation of the cavity-forming inlets overlying film or web. The connection points of the film with the Mounting brackets are in constant contact with the in the operating state stored medium, even at extremely low levels, and are none Exposed to shear stress, which is known for adhesive or welded connections is extremely critical.

The connection points are only the liquid prevailing in the container exposed to pressure and are not subject to changing temperature fluctuations, such as when fastening film systems in the area of the tank wall.

The film covering and sealing the tank bottom is also in the case of in the tank arranged stirring elements are not exposed to movements that lead to tearing the film could lead. Even when emptying or cleaning the tank Due to the stable position of the film in only one plane, none of them work forces favoring the film. Existing in certain tanks Pipelines a short distance above the tank bottom, e.g. B. for the removal of water layer settling over the tank bottom, now do not require any special complex sealing measures more, since these are not through a Foil system must be performed or when retrofitting the Leak protection lining must be taken into account.

The leak protection lining according to the invention can be manufactured inexpensively and only requires a small amount compared to the previously known solutions Assembly effort. It is particularly suitable for retrofitting already in  Operational tanks suitable and universal for tanks of different designs and execution can be used.

The invention will be explained below using several examples. In the show associated drawing

Fig. 1 a section of a tank in the area of the tank wall / tank bottom with a leak-resistant lining, in perspective view,

Fig. 2 shows the detail of a tank with gradually sloping bottom and a leakage protection lining, as a cross-sectional view,

Fig. 3 shows the corner area of a tank with a leak-resistant lining, wherein the leg is equipped for fixing the coating film with a plastic, as a cross-sectional view,

Fig. 4 shows the corner area of a tank with a leak-resistant lining, wherein the leg is formed for mounting the foil as the flexible flap, as a cross-sectional view,

Fig. 5 shows the corner area of a tank with a leak-resistant lining, wherein the mounting bracket is designed as a one-piece plastic component, as a cross-sectional view,

Fig. 6 shows the corner area of a tank with a leak-resistant lining, wherein the leg extending parallel to the tank wall has a collar with itself followed cavity, as a cross-sectional view,

Fig. 7 shows the corner area of a tank with a leak-resistant lining, the film or sheet is attached with a mechanical clamping device, as a cross-sectional view, and

Fig. 8 shows the detail "X" of FIG. 7 in an enlarged view.

The steel tank shown in FIG. 1 is single-walled and consists of the tank wall 1 and the tank bottom 2 , which are arranged at right angles to one another. Such a closed tank is e.g. B. intended for the storage of heating oil and has a length of 20 m and a height of 10 m. The tank also has a closable opening in the form of a manhole on the upper side (not shown). Before introducing a leak protection lining, the empty tank is cleaned and the tank bottom 2 is checked for leaks, repaired if necessary and provided with a corrosion-inhibiting paint or sealed with a hardenable liquid plastic. The leak protection lining consists of a circumferential fastening bracket 4 , which is installed in the corner area between the tank wall 1 and the tank bottom 2 , a cavity-forming insert 3, and a media-resistant film or sheet 5 lying on the cavity-forming insert 3 , which runs all around on the parallel to the tank bottom 2 Leg 4 b is attached media-tight all around.

There are various versions of this basic structure of the leak protection lining, which will be discussed in more detail below. In the case of closed tanks, such as those without a removable lid, the fastening bracket 4 is formed from several individual parts due to the relatively small opening as a manhole, which are connected to one another during the assembly of the leak protection lining. In the embodiment shown in FIG. 1, the fastening angle 4 consists of prefabricated angle sections 4 ′, 4 ″, which each have a length of 2 m, for example. The individual angle sections are made of stainless steel with a material thickness of 6 mm and each have one Leg length of 0.2 m. The individual angular sections 4 ', 4 "for forming the circumferential fastening bracket 4 are positioned by spacers 6 such that a small distance of approximately 2 mm remains from the tank bottom 2 and the tank wall 1 , through which the required Cavity 7 is formed for the leakage monitoring. The spacers 6 can be designed in various ways, for. B. as a cavity-forming insert or as molded nubs or webs on the legs 4 a and 4 b. After positioning the angular sections 4 ', 4 ", these are fixed by means of a tack weld between the tank bottom 2 and the legs 4 b running parallel to this. Then the abutting abutting narrow sides of the angular sections 4 , 4 " are welded to one another in a media-tight manner, such as illustrated by the weld 8 shown. Then a V-shaped circumferential weld 9 is attached to the upper edge of the leg 4 a running parallel to the tank wall 1 , through which the leg 4 a is connected to the tank wall 1 in a media-tight manner. Prior to mounting the mounting bracket 4 are in the tank wall 1, in the area of extending parallel to the tank wall 1 a leg 4, installs the necessary connection fitting 10 for leakage monitoring. A commercially available vacuum leakage indicator is connected to this. The cavity-forming insert 3 is placed on the tank bottom 2 on the free space enclosed on the bottom side by the circumferential leg 4 b. This consists, for. B. from a fleece-lined flexible PEHD grid, which is rolled out and, as shown in Fig. 1, bears against the inward-facing end face of the circumferential leg 4 b.

The height of the insert 3 is dimensioned so that an almost paragraph-free connection to the leg 4 b is guaranteed. On the insert 3 , a media-tight film or web 5 is placed, which is cut in its dimensions so that it overlaps the circumferential leg 4 b by an amount that is greater than half the depth of the leg 4 b. As a film z. B. a flexible polypropylene film with a thickness of 1.5 mm can be used. The film or sheet can, depending on the type of attachment and the material of the leg 4 b running parallel to the tank bottom, consist of different materials, provided that this is permanently resistant to the medium to be stored. The PEHD grid as a cavity-forming insert can consist of several individual sections, the suction and test lines made of PVC hose material then being laid between the joints of the grid and connected to the corresponding connecting piece 10 .

The main advantage of this leak protection lining is that it is very simple Assembly and a low manufacturing cost. It can easily be used for the below various tank bottom designs can be used and enables a tension-free laying of the film.

As shown in FIG. 1, the area of tanks particularly susceptible to corrosion, the transition from wall to floor, can be completely monitored for any leaks that occur.

In FIG. 2, the lower part is shown a tank with an inclined bottom 2 with an outlet cone 11 as a cross section. Until now, such tanks could only be retrofitted with a complete lining, without a flexible film system.

The circumferential mounting bracket 4 consists of prefabricated angle sections, the leg 4 b running parallel to the tank bottom 2 already having the required angle of inclination. The cavity-forming insert 3 covers the entire tank bottom 2 . The mounting bracket 4 lies with its bottom leg 4 b on the insert 3 . At the points where the leg 4 b is welded to the tank bottom 2 , the insert 3 has corresponding recesses. The bottom leg 4 b has an inwardly directed, beveled end piece, for. B. in the form of a wedge to ensure a smooth transition of the film 5 in the overlap area.

In cases where the tank is equipped with a removable cover, the circumferential mounting bracket 4 can also be used as a complete, prefabricated component.

The embodiment variant shown in FIG. 3 differs from the variant according to FIG. 1 only in the following . The two legs 4 a and 4 b of the angle sections 4 ′, 4 ″ of the fastening angle 4 are delivered as individual parts and are only closed during assembly in the tank welded at an angle, which is indicated by the weld seam 12. The leg 4 b running parallel to the tank bottom 2 is provided on its upper side, in the overlap area with the film 5 , with a weldable or glueable plastic coating 13. In the case of an adhesive coating, it can also the inside of the overlap area of the film 5 has already been coated with an adhesive, the adhesive layer being covered by a peelable film. The adhesive or welding of the film requires a relatively small amount of manual work and can be implemented using the technology which is conventional per se especially to whom n the mounting bracket consists of only a few angle sections or is available as a complete prefabricated component. In the area of the weld seams of the legs 4 b, a manual plastic re-coating is then still required after the welding process.

In FIG. 4 a further embodiment is shown in which the legs of the attachment angle member 4 are made of different materials. The parallel to the tank wall 1 leg 4 a is made of stainless steel and the parallel to the tank bottom 2 leg 4 c is formed as a flexible cloth made of a suitable plastic, for. B. an elastomeric material, and is formed on the leg 4 a. In all of the design variants according to the invention, at least the leg of the fastening bracket running parallel to the tank wall should be designed as a stable component. The flexible tabs 4 c of the individual angular sections are then designed so that they overlap and are welded or glued together. If the flexible tab is made of an elastomer, a media-resistant sheet 5 made of the same material can also be used. The media-tight connection can then be made by vulcanization during assembly.

In FIG. 5, an embodiment is shown, in which the cavity 7 between the mounting bracket 4 and the adjacent sections of the tank wall 1 and the bottom plates 2 is formed by the cavity-forming inserts 3 and 14. The mounting bracket 4 is designed as a one-piece plastic component which bears against the cavity-forming inserts 3 and 14 . The position of the mounting bracket 4 is essentially by a flexible circumferential plastic bracket 15 which is attached to the inside of the tank wall 1 and the upper portion of the leg 4 a of the mounting bracket 4 by gluing. The individual angular sections, which can be designed with a tongue and groove as a plug connection, are either connected to one another in a media-tight manner by gluing or welding. The overlap area of the film 5 is also connected to the leg 4 b of the mounting bracket 4 by gluing or welding. This version is used in particular when the tank wall 1 to be retrofitted with a leak protection lining already has a plastic coating or is provided with a rubber coating.

A similar embodiment is shown in FIG. 6, which differs from the embodiment according to FIG. 5 only by a different embodiment of the leg 4 a. The leg 4 a of the plastic mounting bracket 4 has at its upper end a collar 16 , followed by an undercut in the direction of the tank bottom 2 , through which the cavity 7 for leakage monitoring is formed, which is filled with a cavity-forming insert 14 . This is necessary so that in the operating state, due to the applied liquid pressure, no shear forces can act on the adhesive connections between the tank wall / collar and film / leg. Of course, the leg 4 a can be equipped with a molded spacer instead of the undercut and the insert. The collar 16 is connected to the tank wall 1 in a media-tight manner by gluing. The collar 16 can preferably also be wedge-shaped, with an acute-angled profile pointing upwards.

The leak protection lining finally shown in FIG. 7 is designed analogously to that shown in FIGS . 1 and 3, only with the difference of a different type of fastening of the film or web 5 to the corresponding leg 4 b of the fastening angle 4 . The film or web 5 is attached to the leg 4 b by means of a mechanical clamping device 17 , which is shown enlarged in FIG. 8. On the parallel to the tank bottom 2 leg 4 b are arranged at a constant distance from the other leg 4 a upwardly projecting threaded bolts 17 a circumferentially at equal intervals. After mounting the mounting bracket 4 , a circumferential sealing tape 17 b is first fitted without creases, which is provided with precisely fitting holes in accordance with the distance between the bolts 17 a. The sealing tape 17 b consists of a media-resistant, elastic plastic material. Subsequently, the overlapped area of the film 5 , which is provided with prepared holes for plugging onto the bolts 17 a, is fitted without creases and lying thereon, a further sealing tape 17 c. Thereafter, clamping rails 17 d are plugged onto the bolts 17 a, a clamping rail 17 d extending over a plurality of bolts 17 a. Washers 17 e and spring washers 17 f are attached to the bolts 17 a and the clamping rails 17 d are fastened by means of screw nuts 17 g, while maintaining a constant clamping voltage. With regard to further details and design variants of the clamping device, reference is made to the already mentioned document DE 29 80 7285 U1 by the applicant.

A composite system consisting of several can also be used as a media-resistant film or web Films or sheets are used.

Claims (19)

1.Leak protection lining for tanks for storing water-polluting media, consisting of at least one pressure-stable, cavity-forming insert and at least one media-resistant film or sheet of plastic resting on this insert, characterized in that in the corner area between the tank wall ( 1 ) and the tank bottom ( 2 ) circumferentially a mounting bracket ( 4 ) with a leg ( 4 a) running parallel to the tank wall ( 1 ) and a leg ( 4 b, 4 c) running parallel to the tank bottom ( 2 ) is fixed in position, the parallel to the tank wall ( 1 ) extending leg ( 4 a) is stable and is connected to the tank wall ( 1 ) in a media-tight manner, a cavity ( 7 ) suitable for leakage monitoring is arranged between the mounting bracket ( 4 ) and the wall and bottom sections of the tank adjacent to it, the bottom-side cavity-forming insert ( 3 ) either the entire tank bottom ( 2 ) or the tank bottom area h (b 4, 4 c) outside the running parallel to the tank bottom (2) leg of the attachment angle member (4) covered and which rests on the cavity forming insert (3) the film or sheet (5) on the running parallel to the tank bottom (2) leg ( 4 b, 4 c) of the mounting bracket ( 4 ) is attached media-tight. 2. Leak protection lining according to claim 1, characterized in that the circumferential fastening bracket ( 4 ) consists of several individual parts ( 4 ', 4 ", 4 a, 4 b, 4 c), which are connected to one another in a media-tight manner after assembly. 3. leak protection lining according to one of claims 1 or 2, characterized in that in the tank wall ( 1 ), in the region of the parallel to the tank wall ( 1 ) leg ( 4 a) of the mounting bracket ( 4 ) connecting piece ( 10 , 11 ) for a leakage monitoring device is provided. 4. leak protection lining according to one of claims 1 or 2, characterized in that in the tank bottom ( 2 ) connection piece ( 11 ) for a leakage monitoring device are provided. 5. leak protection lining according to one of claims 1 to 4, characterized in that to form the cavity ( 7 ) between the mounting bracket ( 4 ) and the adjacent wall and bottom portions of the tank spacer ( 6 ) or between the mounting bracket ( 4th ) and an inlay ( 14 ) are arranged adjacent to this wall sections of the tank. 6. leak protection lining according to claim 5, characterized in that the required spacers ( 6 ) on the mounting bracket ( 4 ) are integrally formed. 7. leak protection lining according to one of claims 1 to 6, characterized in that the parallel to the tank bottom ( 2 ) extending leg ( 4 b) on the tank bottom ( 2 ) is fixed. 8. leak protection lining according to one of claims 1 to 7, characterized in that the parallel to the tank bottom ( 2 ) extending leg ( 4 b) of the mounting bracket ( 4 ) is arranged in the installed state at about the same height as the cavity-forming insert ( 7 ). 9. leak protection lining according to one of claims 1 to 8, characterized in that the legs ( 4 a, 4 b, 4 c) of the mounting bracket ( 4 ) consist of identical or different materials. 10. leak protection lining according to one of claims 1 to 9, characterized in that the parallel to the tank bottom ( 2 ) extending leg is designed as a flexible tab ( 4 c) which with the parallel to the tank wall ( 1 ) extending leg ( 4 a) connected is. 11. Leakage protection lining according to one of claims 1 to 10, characterized in that on the parallel to the tank bottom ( 2 ) extending leg ( 4 b, 4 c) an adhesive, weldable or vulcanizable plastic layer ( 13 ) is attached with the the film or sheet ( 5 ) lying on the insert ( 3 ) is connected in a media-tight manner. 12. Leak protection lining according to one of claims 1 to 11, characterized in that the parallel to the tank bottom ( 2 ) extending leg ( 4 b) is designed as a stable component and at a predetermined distance from the tank wall ( 1 ) with upwardly projecting fastening bolts ( 17 a) is fitted, on which an elastic base ( 17 b), on which the film ( 5 ) and then a sealing tape ( 17 c) are placed, which are attached by means of clamping rails ( 17. ) Extending over a plurality of bolts ( 17 a) d) are locked in a media-tight manner under pressure. 13. Leak protection lining according to claim 12, characterized in that the bolts ( 17 a) are designed as threaded bolts and the clamping rails ( 17 d) are locked by means of spring-loaded fastening nuts ( 17 g). 14. Process for equipping a tank with a leak protection lining, characterized by the following process steps:

• a) Arrangement of a circumferential mounting bracket ( 4 ) in the corner area of the tank, between the tank wall ( 1 ) and the tank bottom ( 2 ) at a defined distance from the tank wall ( 1 ) and the tank bottom ( 2 ), around the cavity ( 7 ) required for leakage monitoring to build,
• b) media-tight attachment of the parallel to the tank wall (1) extending leg (4a) of the attachment angle member (4) on the tank wall (1) by gluing or welding,
• c) placing a cavity-forming insert ( 3 ) covering the entire tank bottom ( 2 ) or the tank bottom area between the circumferential leg ( 4 b, 4 c) of the fastening bracket ( 4 ) and parallel to the tank bottom ( 2 ) on the tank bottom ( 2 ) ,
• d) Preparation of at least one film or sheet ( 5 ) as a blank in the appropriate dimensions for media-tight covering of the tank bottom ( 2 ), the blank being dimensioned such that the leg ( 4 b, 4 c) running parallel to the tank bottom ( 2 ) the mounting bracket ( 4 ) is overlapped,
• e) placing the tailored foil or web (5) on the insert (3) and attaching the overlap areas of the foil or web (5) on the running parallel to the tank bottom (2) arms (4 b, 4 c) of the attachment angle member (4) by welding, gluing, vulcanization or by means of a mechanical clamping device ( 17 ) and
• f) Installation of a leakage monitoring device.

15. The method according to claim 14, characterized in that the circumferential mounting bracket ( 4 ) is assembled during assembly in the tank from several individual parts ( 4 ', 4 ", 4 a, 4 b, 4 c), which are connected to each other in a media-tight manner. 16. The method according to any one of claims 14 or 15, characterized in that the parallel to the tank bottom ( 2 ) extending leg ( 4 b, 4 c) before welding the individual parts ( 4 ', 4 ") of the mounting bracket ( 4 ) on the tank bottom ( 2 ) is fixed in position. 17. The method according to any one of claims 14 to 16, characterized in that at a retrofit of the tank as a first step, a leak test the area to be lined is carried out. 18. The method according to any one of claims 14 to 17, characterized in that on the surfaces to be lined with a curable liquid plastic and / or corrosion-inhibiting paint is applied. 19. The method according to any one of claims 14 to 18, characterized in that the cavity-forming insert ( 3 ) is formed from several individual parts, between which suction and test lines are laid, which are connected to the connecting piece ( 10 , 11 ).