EP2957526B1 - Tank lining and method for producing the same - Google Patents

Description

The disclosure relates to a tank liner and a method of manufacturing a tank liner.

background

An inner tank shell is made according to the dimensions of a tank made of plastic sheets. It is used to equip the tank with a second wall. For this purpose, an intermediate layer is initially installed in the tank, such as fleece. This fleece also conducts air under pressure. Thereafter, the shell is installed in the tank. It is held by a vacuum on the tank wall, regardless of the level of the tank. The system is monitored by a leak detector. If a leak occurs, the leak detector detects this by changing the pressure and an alarm is triggered. Tank inner sheaths are usually intended for the renovation of existing tanks.

In order to avoid ignition hazards due to electrostatic charges in potentially explosive atmospheres in steel tanks for the storage of gasoline, appropriate precautions must be taken. For example, the tank inner shell should be earthed and have a surface resistance of less than 10 ⁹ Ω (measured at 23 ° C and 50% relative humidity) have.

In the case of a plastic tank inner shell, sufficient electrical conductivity can be achieved by adding additives such as ash or graphite, which are mixed with the plastic. Due to the additives, however, the material properties of the plastic can change negatively. Thus, it may lead to a decrease in the diffusion behavior or the resistance of the plastic to gasoline.

The document EP 0 014 491 A1 discloses a double-walled container for storing combustible media. In an internal plastic wall, a metallic wire mesh is truncated.

The document EP 0 758 620 A1 discloses an interior liner for a tank with a gasoline resistant inner liner. The inner shell has a diffusion-tight layer on its side facing the tank wall. On the tank interior facing side, the inner shell has an electrically conductive layer. The electrically conductive layer may be formed with polyaniline.

The document DE 91 09 544 U1 discloses an inner shell for a thermoplastic elastomer tank.

The document DE 23 58 198 A1 discloses a method for electrically conductive bonding of FRP parts.

Summary

The task is to specify improved technologies for lining a tank.

There are disclosed a tank liner according to claim 1 and a method of manufacturing a tank liner according to claim 8.

The fluid may be a gas or a liquid, for example a fuel such as gasoline, diesel, bio-diesel or ethanol. The tank liner may be used to line a tank, such as a fuel tank. The tank can have a cylindrical shape. The tank can be a steel tank. The tank can have a capacity of 3,000 1 to 100,000 1. Alternatively, the envelope can be used for flexible fuel tanks used in Formula 1 or in aircraft. Such tanks are much smaller than the storage tanks, for example, at gas stations. The flexible tank can have a capacity of 100 1 to 1,000 1. The flexible fuel tank can be made of a flexible material that is welded, glued or vulcanized from webs. On the tracks can later be applied externally a conductive layer. The advantages are similar to a tank inner shell for a cylindrical tank. The sheath (e.g., foil) for the flexible tank may be self-supporting or supported on existing structures, such as the wing of an aircraft on the structures of the wing in the aircraft.

The sheath may consist of a foil or a coated fabric. There may be several material sections connected to the shell. In that case, the sleeve may be composed of seams with seams. The film or the coated fabric may consist of a plastic, in which any barrier layers are involved.

The electrical conductivity of the dissipation layer can be increased by the addition of additives. The dissipation layer may contain carbon black, graphite and / or nanotubes.

The shell may be formed in multiple layers. Between two plastic layers (eg film webs) may be arranged a barrier layer.

The dissipative layer can be dissipative. It is capable of dissipating a substance or material with a resistivity of more than 10 ⁴ Ωm and less than 10 ⁹ Ωm. The resistivity is the electrical resistance of a substance or material measured on a sample of the unit length and the unit cross-sectional area. Furthermore, an article or device having a surface resistance between 10 ⁴ Ω and 10 ⁹ Ω, measured at 23 ° C and 50% relative humidity, or having a surface resistance between 10 ⁴ Ω and 10 ¹¹ Ω, measured at 23 ° C and 30% relative humidity, conductive. Dissipative substances or articles and equipment made of dissipative materials do not store electrical charge when in contact with earth. Also known as dissipative are articles and devices if they consist of dissipative materials. The surface resistance is the electrical resistance measured on the surface of an object. It is measured between two parallel electrodes of small width and each 100 mm in length, which are 10 mm apart and in contact with the surface to be measured. The measuring voltage is 100 V. With decreasing air humidity, the surface resistance usually increases considerably (see Technical Rules for Operational Safety, TRBS 2153, Prevention of Ignition Hazards Due to Electrostatic Charges ", GMB1 No 15/16 of 9 April 2009, p. 278 ).

The discharge layer is arranged on a surface facing away from the interior of the shell. The interior of the surface facing away from the shell is also referred to as the outside. The Ableitschicht on the outside of the shell has the advantage that the discharge layer is not directly exposed to the fluid - for example, gasoline. As a result, the fluid can not easily attack the Ableitschicht and z. For example, rinse the layer, soften or possibly soften welds of the layer. Furthermore, a material, for example a film, which can be produced more cheaply can be used for the casing. If the Ableitschicht applied after the production of the shell, this has the advantage that, for example, high-frequency welding process for the production of the tank lining is available. The arrester layer disposed on the outside of the envelope may have a surface resistance of less than 10 ⁹ Ω or less than 10 ⁸ Ω, measured at 23 ° C and 50% relative humidity. The dissipation layer can be firmly connected to the shell.

The shell may be made of one or more flexible materials. The sheath can be formed from a plurality of mutually welded film webs, wherein the Ableitschicht at least partially applied to the film webs. The Ableitschicht can be arranged on welds of the film webs.

It can be provided that the casing is first completely manufactured, for example by welding a plurality of film webs. Subsequently, the Ableitschicht can be applied at least in sections on the outside of the finished casing, for example in the form of a lacquer. If the Ableitschicht is used up on individual film webs, for example by laminating, these film webs may be harder to work and the welds may not be so stable.

The dissipative layer can substantially completely cover the surface of the sheath. It can be provided that the outside of the shell is completely covered by the Ableitschicht.

A fleece is usually installed as an intermediate layer between the shell and the tank. When using a conductive fleece that is firmly connected to the outside of the shell and independent of a negative pressure between the shell and a tank inner wall holds the shell, the shell may be made of a non-conductive material. Especially the conductive additives in films (for the shell) can limit their gasoline resistance. If one waives these additives, the costs for the sometimes very expensive additives are saved. In addition, it is also easier to access standard foils because not all film manufacturers can produce conductive foils or such conductive additives can not be processed with all production systems.

When using a lacquer, for example, after the welding of the film webs, the shell is coated from the outside with a conductive lacquer (eg with surface resistance of at least 10 ⁸ Ω, measured at 23 ° C and 50% relative humidity). This has the advantage that the conductive coating with the paint can not affect the welding result when welding the film webs, since it is applied after the welding process. In addition, high-frequency welding can be used, which usually work only limited when welding conductive film webs. In addition, here too, the coating or coating is applied to the outside, whereby it is not exposed to the medium inside the shell. There it could be attacked by abrasion as a result of flow of the liquid as well as by the action of the liquid on the coating, which may possibly lead to the release of the coating. The drainage layer can be earthed via the dome by screwing it to the shell on the dome, ie with the outside (conductive side) resting on the dome of the tank or being pressed against it.

The Ableitschicht can be applied, for example, during production on the outside of the shell, for example, be glued. B. a dissipative nonwoven is glued, or in another production process z. As by lamination (with surface resistance of at least 10 ⁸ Ω - measured at 23 ° C and 50% relative humidity). In this case, a film is processed to a tank inner lining, which already has a conductive outer layer.

The film of the shell may be produced such that one side of the film is formed with one or more barrier layers and the film is conductively formed by an additive. This side of the film is then taken into account in the production of the inner lining and welded so that the Innauskleidung is completely conductive on the outside, ie the conductive Side is arranged outside and possibly electrically connected to an additional layer after welding, for example by applying a lacquer layer.

But it may also be that the entire film is provided conductive except the barrier layer or the barrier layers. Then, in the production of the inner lining, it is not necessary to pay attention to which side of the film is conductive. It can be ensured that the entire conductive surfaces can be grounded, for example, over the dome of the tank. This can be achieved by the arrangement of the film webs.

The film webs can each run towards the dished bottom and are then arranged on the dished bottom in such a way that all film webs running longitudinally through the tank (in each case with the length of the tank) are connected to one another externally on the inner lining.

According to another embodiment, the discharge layer may be arranged at least in sections on a surface of the casing facing the interior. The interior facing surface of the shell is also referred to as the inside.

The dissipation layer can be arranged in a bottom region of the envelope. In particular, the dissipative layer can be arranged in the bottom region on the inside of the casing, such that regions of the inside located above the bottom region are free of an electrically conductive material. For example, an upper half of the shell may be free of an electrically conductive material. The dissipation layer may have a surface resistance of less than 10 ⁶ Ω. About the material of the Ableitschicht electrical charges in the fluid, resulting for example during filling, are derived.

The dissipation layer may be formed with one or more strips of the electrically conductive material. The strip (s) may extend the length of the shell. For the further arresting layer, the statements on the arresting layer apply analogously. In particular, the further dissipative layer can be applied as a lacquer layer on the inside of the envelope.

On the inside of the shell, a film web with a width of at least 15 cm and a conductivity (surface resistance) of 10 ⁶ Ω in the lower fifth of the tank and over the entire cylindrical length of the tank can be placed on the existing tank inner shell. The film web can be welded, for example, to the shell. The film web should not be located exactly at the lowest point. The material of the film web may be such that the web is thermally welded to the tank inner shell. The film web can then be guided upwards via a dished bottom of the tank or via side walls of the tank in the area of the dome and, for example, grounded via the dome or the tank.

It may also be provided that a drainage layer is arranged at least in sections on the inside and the outside of the shell. The dissipation layers may be formed of the same or different materials.

Alternatively or additionally, a flexible material with a diameter of at least 4 mm and an electrical conductivity of 10 ⁶ Ω in the interior of the shell in the lower fifth of the tank can be arranged. It can be guided over the entire bottom of the shell and fastened there, for example with tabs. The flexible material should not be in the lowest area. Then the material, such as a plastic tape, can be led over the dished bottom or over the wall to the dome of the tank and grounded there.

Furthermore, another material with a diameter of at least 4 mm and an electrical conductivity of at least 10 ⁶ Ω can be used, for example a tube. The tube can run parallel to the tank bottom in the interior of the shell in the lower sixth of the tank over the entire length of the tank and protrude into the tank. It can also be stabilized by supports on the bottom of the tank so that it is not self-supporting over the entire tank length. The tube can be attached to a filling line and be discharged over it. Alternatively, for example, another tube from the tank lid may hold the conductive tube above the bottom of the tank and drain it over the dome lid.

Alternatively, a flexible material with a diameter of at least 4 mm and an electrical conductivity of 10 ⁶ Ω on the side of the tank may be attached, the Dom facing away. This may be, for example, a rope which is fastened to the dome in such a way that, for example, it can divert stresses via the dome into the tank.

Alternatively, a pipe or a flexible material can always be kept at a substantially same height in the tank by means of a float. In this case, too, it can then be earthed, for example, via the dome.

When using a material in the interior of the shell in the manner of a pipe, a cable (flexible material) or a rope can be dispensed with arranging the Ableitschicht on the surface of the shell. Hereby, embodiments are provided in which the shell without Ableitschicht forms the tank inner lining. For the discharge, the material in the interior can provide.

The drainage layer may be grounded, for example at the dome of the tank. The film webs of the shell may be arranged in the tank such that the conductive layer can be earthed at one point, for example at the dome.

A thickness of the shell may be less than 2 mm.

The dissipative layer may be welded or glued to the envelope.

The features disclosed in connection with the tank liner can also be used for the manufacturing process and vice versa.

Description of embodiments

Fig. 1

einen Tank mit einer Innenauskleidung nach dem Stand der Technik,

Fig. 2

eine schematische Darstellung einer mehrschichtigen Tankinnenauskleidung,

Fig. 3

einen Tank mit einer Tankinnenauskleidung mit angeschweißtem elektrisch leitfähigem Streifen,

Fig. 4

einen Tank mit einer Tankinnenauskleidung mit einem Kabel,

Fig. 5

einen Tank mit einem leitfähigem Ableiter an einer Saugleitung,

Fig. 6

einen weiteren Tank mit einem Ableiter und

Fig. 7

einen Tank mit einem leitfähigen Seil.

In the following, exemplary embodiments are explained in more detail with reference to FIGS. Show it:

Fig. 1

a tank with an inner lining according to the prior art,

Fig. 2

a schematic representation of a multilayer tank inner lining,

Fig. 3

a tank with a tank inner lining with a welded electrically conductive strip,

Fig. 4

a tank with a tank lining with a cable,

Fig. 5

a tank with a conductive trap on a suction line,

Fig. 6

another tank with a trap and

Fig. 7

a tank with a conductive rope.

Hereinafter, like reference numerals are used for like components.

Fig. 1 shows the construction of an inner lining in a tank according to the prior art. In the upper end of a substantially cylindrical tank of conventional construction, a dome 17 is welded with a flange to which a cover 18 can be screwed. On the inner wall of the tank is an intermediate layer 14 of a possibly conductive and air-permeable material (eg with a surface resistance of at least 10 ⁹ Ω - measured at 23 ° C and 50% relative humidity) and on the inside of the liner a flexible inner lining 13 at , In the upper part of the dome 17, the intermediate layer is usually replaced by a layer of sponge rubber or the like (not shown), so that the space between the inner liner 13 and the tank wall 15 is sealed upwards. This layer also serves as a support for a clamping ring 16, with which the inner lining 13 is firmly clamped in the dome 17. The clamping ring 16 may be a V-shaped clamping ring with round cord. By a vacuum between the inner lining 13 and the tank wall 15, the inner lining 13 is held on the tank wall. In addition, the inner lining 13 and the tank wall 15 can be monitored.

Fig. 2 shows the construction of a multilayer inner lining 5. On one side an electrically conductive layer 12 is arranged, for example made of a dissipative material. This is followed by a film layer 6, for example made of plastic, and a barrier layer 7. Finally, a further film layer 10 (made of the same or a different plastic as film layer 6) and a further electrically conductive layer 11 are formed. The further electrically conductive layer 11 may be made of the same material or a different material as the electrically conductive layer 12.

Fig. 3 shows a further embodiment on the inside of the inner lining 13, an electrically conductive strip 20 is arranged, for example, welded. The strip 20 is arranged in the bottom region 21 of the tank 15 and extends over the length of the tank 15. The strip is earthed at the dome 17.

Fig. 4 shows an embodiment in which a cable 22 is secured by means of holders 23 at the bottom of the tank 15. The cable 22 is made of an electrically conductive material. The cable is earthed at the Dom 17. The cable 22 extends over the entire length of the tank 15. The holder 23 may be arranged at regular intervals from each other.

In Fig. 5 a tank 15 with a conductive arrester 25 is shown. The arrester 25 is attached to a suction line 24, which is earthed at the dome 17.

Fig. 6 shows a tank 15 with a trap 25 which is grounded at the dome 17.

Fig. 7 shows a tank 15 with a conductive rope 26. The rope 26 is in contact with the bottom of the inner liner at one point. The rope is earthed at Dom 17.

The features disclosed in the specification, the claims and the figures may be relevant to the realization of embodiments individually or in any arbitrary combination with each other.

LIST OF REFERENCE NUMBERS

1.

Outside of the tank

Second

Inside the tank

5th

inner lining

6th

film layer

7th

junction

8th.

Interior lining outside

9th

Interior lining inside

10th

further film layer

11th

another electrically conductive layer

12th

electrically conductive layer

13th

inner lining

14th

liner

15th

tank

16th

clamping ring

17th

cathedral

18th

Dorn cover

20th

conductive strip

21st

Ground area of the tank

22nd

electric wire

23rd

holder

24th

suction

25th

arrester

26th

conductive rope

Claims (8)

1. A tank inner lining with an inner cover (6) surrounding the inner region (2) for receiving a fluid, wherein the surface of the inner cover (6) has a conductive coating (12) being arranged on a surface of the inner cover (6), at least in sections, which comprises an electrically conductive material, characterized in that the conductive coating (12), composed of a varnish, is arranged at last in sections on a surface of the inner cover (6) opposite of the inner region (2).
2. Tank inner lining according to claim 1, wherein the inner cover (6) is formed by a plurality of film sheets welded together, and the conductive coating (12) is applied at least in sections onto these film sheets.
3. Tank inner lining according to one of the preceding claims, wherein the conductive coating (12) has a surface resistivity of less than 10⁹ Ω.
4. Tank inner lining according to one of the preceding claims, wherein the material of the conductive coating (12) is conductive.
5. Tank inner lining according to one of the preceding claims, wherein the conductive coating (12) being grounded.
6. Tank inner lining according to one of the preceding claims, wherein a thickness of the inner cover (6) is less than 2 mm.
7. Tank inner lining according to one of the preceding claims, wherein the film sheets run longitudinally and are electrically connected to one another via a torispherical head of a tank.
8. A method of manufacturing a tank inner lining comprising:

   - providing an inner cover (6) with an inner region (2) for receiving a fluid and

   - applying a conductive coating (12) to at least a section of a surface of the inner cover (6),

   wherein the conductive coating (12) comprises an electrically conductive material, wherein the inner cover (6) is produced by welding several film sheets together, characterized in that, after welding, the conductive coating (12) is applied in form of a varnish to a surface of the inner cover (6) opposite to the inner region (2).

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