EP1953094B1 - Double-wall tank - Google Patents

Abstract

Double-walled tank or container comprises a glass mat (31) and a fiberglass fabric (29) placed on a spacer foil in the transition region between the base and the side walls of a leakage protection lining. Preferred Features: The fiberglass fabric is arranged so that the amount of yarn running from the base to the side walls is larger than the amount of yarn running parallel to the side edges of the base.

Description

Field of the invention

The present invention relates to a double-walled tank or a double-walled container, in particular for liquids, with a tank bottom and tank side walls and a leakproof lining spaced from the tank bottom and the tank side walls, which leak protection lining is formed by a spacer film and at least one fiber-reinforced plastic layer applied to the spacer film ,

State of the art

The German Offenlegungsschrift DE-OS-2658088 discloses a tank for underground storage of liquids such as fuel oil or diesel. The tank has a steel container and a surrounding insulating jacket. The steel tank is surrounded by a rot-proof, even gridded spacer layer. On the spacer layer, a gas- or liquid-tight envelope made of a fiber-reinforced plastic is applied. The spacer layer consists of a uniformly pimped laminated body. The composite may be formed of expanded metal, paper or a braid.

As reinforcing material usually glass mats are incorporated in leak protection liners. Glass mats are glass fiber mats made of alkali-free E glass fibers, and are used as low-cost reinforcing layers. The cohesion of the cut, tangled short glass fibers of the glass mat is achieved by a binder that dissolves in polyester resin contact and u.a. serves as a bonding agent between fibers and UP resin. These glass mats contribute to a substantial reinforcement of the leak protection lining. The disadvantage, however, is that the leak-proof linings are generally less flexible, so that the leak-resistant linings rupture, especially in the case of large tanks. Critical areas are located in the transition area between floor and walls, where the greatest pressure is applied.

From the DE-A 199 40 502 is a manufactured in the winding process plastic container for storage of liquids known. This container is constructed from a variety of layers. First, an inner wall is made of a first layer of glass fiber fabric, a second layer of wound rovings, a third layer of glass silk fabric, and a fourth layer of wound rovings. This inner wall is saturated with polyester resin. After curing of the resin we enter on the inner wall Grid fabric composed of a first layer of polyester-saturated, glass silk fabric, a second layer of a film, a third layer of its grid, a fourth layer of its film and a fifth layer of a polyester-saturated glass fabric. The outer wall consists of a first layer of rovings, a second layer of glass silk fabric, a third layer of rovings, a fourth layer of glass silk fabric and a fifth and sixth layer of rovings. The outer wall is saturated with polyester. The films prevent the grid from becoming saturated with the plastic. This creates between the inner wall and the outer wall a cavity forming mesh fabric. To seal tightness, this cavity can be filled with a liquid or subjected to negative pressure. Because such a container is made of plastic, it can not be leak tested with a leak detector. If a leak is detected, therefore, the location of the leak can be found only with a very high search cost. It is not even immediately apparent whether the leakage is present in the outer wall or the inner wall.

From the EP-A 0 816 258 is a leak-proof lining for a tank known. This double-walled lining has a double pile covered with a laminate layer of fiberglass reinforced plastic. The laminate layer may be covered with a cover layer. The reinforced plastic doublepolished forms a cavity that can be monitored. The double pile fabric is an uncut multi-layer fabric with a top fabric and a lower fabric, which are kept apart by pile threads. The fibrous material for the upper fabric, the lower fabric and the pile threads serve in particular glass fibers, carbon fibers, aramid fibers. These can be spun as staple fibers into yarns or formed as mono- or multifilaments. A leakage protection lining made of a double-pile fabric has the disadvantage that the cavity can be easily filled in careless application of plastic, so that not everywhere a cavity is formed. Therefore, such a tank is often not everywhere double-walled in the context of the present invention.

The EP-A-0 470 321 discloses a tank having an outer wall and a leak protection liner formed from a laminate consisting of a nap foil and a plastic layer. The edges of the plastic layer are connected to the outer wall to form a leak-testable space between the leak-proofing lining and the outer wall. The plastic layer has as Reinforcing a multi-layer glass fiber fabric, the superposed layers are joined together by weft and / or warp threads, which pass from one layer to another layer.

The leakproof lining equipped with the above-mentioned multi-layered glass fiber fabric has the advantage that it is particularly unyielding (large modulus of elasticity). However, this stiffness has the disadvantage in the lining of large-volume tanks that the leak protection lining may burst. When filling a large-volume tank, the outer walls are happy to give way and thus the entire pressure load acts on the leak protection lining. Because the leakage protection lining has a very large modulus of elasticity, this leads to cracking in the event of overstressing. The consequence of this is a leakage of the leak protection lining. Another problem of the known multi-layered fabric is that it absorbs much synthetic resin. After commodity prices have risen sharply in recent years, this leads to an increase in the cost of production.

Object of the invention

Based on this prior art, the invention provides the task of proposing a double-walled tank, which withstands large pressure loads. In particular, it is an aim to develop a double-walled tank so that it does not break in the transition region between the floor and the wall. Another goal is to propose a tank, which is inexpensive to produce.

description

According to the invention the object is achieved in that at least in the transition region between the bottom and the side walls of the leak protection lining on the spacer sheet a glass mat and a glass fabric are applied. This has the advantage that in this area a particularly large modulus of elasticity is achieved and that the risk of cracking is reduced. The use of a glass silk fabric has the advantage that compared to a glass mat, the resin is absorbed faster and better distributed. Another advantage is that when laying out any interfering glass parts are split off because in glass fiber fabric rovings (fiber strands) are used with infinitely long filament yarns. These filament yarns are preferably untwisted.

According to a preferred embodiment, the tensile strength of the fiberglass fabric is greater in a certain first direction than in a second direction, which may be orthogonal to the first direction, for example. This makes it possible to selectively reinforce the transitional area between the floor and the walls by arranging the glass silk fabric so that the greater tensile strength runs in the direction from the floor to the walls. Advantageously, the silk fabric has an unequal number of warp and weft threads and is arranged so that the number of threads extending from the bottom to the side walls is greater than the threads running parallel to the side edges of the tank. Advantageously, the proportion of warp and weft threads at least one layer is unequal size. This has the advantage that the tensile strength in a certain direction can be greater than transverse to it. After the glass silk fabric is provided in practice in the form of rolls, it is expedient to tailor the glass silk fabric so that the greater tensile strength runs in the longitudinal direction of the roll. A greater tensile strength can be achieved by the weight proportion of the warp threads is greater than that of the weft threads. Advantageously, the ratio of warp and weft threads is greater than 55:45, preferably greater than 60:40, and most preferably> 65:35. If the number of warp threads is greater than that of the weft threads, this has the advantage that the glass silk fabric can be cut to length from the roll in practically any lengths. Advantageously, the ratio of warp to weft yarns is about 70:30.

According to another advantageous embodiment, the warp and weft threads of the silk fabric are unevenly strong, and the silk fabric is arranged so that the weight of the threads extending from the bottom to the side walls is greater than the weight of the threads running parallel to the side edges of the tank. In this way, the tensile strength of the leak protection lining in the transition area floor / jacket can be further improved. Conveniently, a second fiberglass fabric is applied to the first fiberglass fabric.

In order to further increase the E-modulus of the leak-proof lining, the first and / or second glass-silk fabric may be formed as a hybrid weave. This means that in addition to the existing glass threads, carbon threads can also be incorporated into the glass silk fabric. Preferably, the carbon fiber are present as warp or weft threads. To achieve reinforcement on all sides, the carbon fibers are preferably as Warp and weft threads.

The layer of glass fiber fabric, or a second layer of the glass silk fabric, provided according to the invention in the transition region between the bottom and side walls of a leak protection lining can also be present over the entire bottom surface and / or over the entire side wall surfaces.

Although various synthetic resins such as epoxy resins, polyurethane resins, polycarbonate resins may be used in principle for the production of the leak protection liner, a polyester resin, novolak (an epoxy-based vinyl ester resin) is preferably used. Polyester resins and novolac have the advantage that they are relatively inexpensive available in the market.

Advantageously, the leak protection lining is a laminate of at least one spacer film, the glass fiber fabric and a plastic layer, wherein the spacer film is applied to the outer wall. This has the advantage that a space which can be checked for leakage is formed between the outer wall and the leak protection lining if the edges of the inner wall remain connected to the outer wall in airtight manner.

It is conceivable to use as spacer film a specially impregnated, studded cardboard or metal foil. Preferably, however, a metal foil is used because it is easier to apply and can withstand greater pressure loads. Preferably, the plastic coating is made of an epoxy, polyester, polyurethane, novolac (an epoxy-based vinyl ester resin) or a polycarbonate resin.

Advantageously, the knobs are designed as a pyramid or truncated cone. Such a film has the advantage that it has a higher compressive strength than conventional metal foils. Also, the film according to the invention can be laid better than conventional films, because it has no tendency to unroll obliquely.

According to a preferred embodiment, the individual knobs are each formed as regular, preferably square truncated pyramids with a base surface and a top surface. This geometry has the advantage that it guarantees a high compressive strength. It has proven to be advantageous if the edge length of the base surface more than twice as long as the edge length of the top surface. Preferably, the edge length of the base surface is approximately between 220% and 380% longer than the edge length of the top surface.

Advantageously, the truncated cones are each arranged in series one behind the other, so that a grid-like, orthogonal pattern is formed. Conveniently, two adjacent truncated cones each have an edge of the base surface in common. In this way, a dense juxtaposition of truncated pyramids is possible. Although square truncated pyramids are preferred, the dimples may also be formed as regular hexagonal or octagonal truncated pyramids. In addition, it is also possible to arrange the knobs as honeycomb pattern. Conveniently, the knobs are each the same size.

Advantageously, the metal foil is made of an aluminum foil with a thickness between 0.15 and 0.25 mm, preferably between 0.18 and 0.22 mm. Preferably, the edge length of the base surface is between 3 and 10 mm, preferably between 4.5 and 8.5, and most preferably between 5.5 and 7.5 mm. Such truncated pyramids can be produced well and have a high compressive rigidity. Advantageously, the height of the dimples is between 0.6 and 1.5 mm, preferably between 0.8 and 1.2 mm. It has proved to be advantageous if the metal foil has a specific weight between 0.62 and 0.78 Kg / m 2, preferably between 0.67 and 0.73 Kg / m 2. With such a specific gravity, a metal foil with low weight and high pressure rigidity can be produced.

Fig. 1

Eine Draufsicht auf eine Distanzhaltefolie;

Fig. 2

Einen Schnitt entlang der Linie 2-2; und

Fig. 3

Ausschnittsweise der Aufbau eines doppelwandigen Tanks, dessen Leckschutzauskleidung ein Laminat ist mit einer Distanzhaltefolie, mindestens einer auf der Distanzhaltefolie angeordneten Glasmatte, einem auf der Glasmatte angeordneten Glasfasergewebe, welche in einer ausgehärteten Kunststoffschicht aufgenommen sind;

Fig. 4

Schematisch und in Teilansicht der Aufbau einer weiteres Ausführungsbeispiel einer erfindungsgemässen Leckschutzauskleidung.

The invention will be described in more detail below with reference to the figures with reference to an application example. It shows:

Fig. 1

A plan view of a spacer sheet;

Fig. 2

A section along the line 2-2; and

Fig. 3

The structure of a double-walled tank, the leak protection lining is a laminate with a spacer sheet, at least one disposed on the spacer sheet glass mat, arranged on the glass mat glass fiber fabric, which are received in a cured plastic layer;

Fig. 4

Schematically and in part the structure of another embodiment a leakage protection lining according to the invention.

The FIGS. 1 to 2 show a metal foil 11 with spaced nubs 13. The nubs 13 are formed as a regular truncated pyramids with an open base surface 15 and a closed top surface 17. The truncated pyramids are arranged close to each other, so that a grid structure is formed. Adjacent truncated pyramids each have a common base edge 19. Due to the dense arrangement of the knobs 13 and their geometric design as a truncated pyramid, a higher compressive strength is achieved than in conventional metal foils.

FIG. 3 shows a detail and in section the structure of a double-walled container with the metal foil 11. The double-walled container has an outer wall 21 and a leak protection lining 23. The outer wall 21 may be a steel wall or masonry. The leak protection lining 23 is formed by a metal foil 11 and a plastic coating 25. The metal foil 11 bears against the outer wall 21 with the cover surfaces 17, so that a gap 27 is formed between the outer wall 21 and the metal foil 11. The gap 27 can be checked by means of leak detectors in the art known manner for any leaks.

In the plastic layer 25, a glass mat 31 and a single-layer glass fiber fabric 29 are incorporated. The combination of a glass mat and a glass fiber fabric 29 gives the leak protection lining a very high strength. As a glass fiber fabric 29, a single-layer glass fiber fabric is preferably used. In comparison with a conventional glass mat, this has the surprising advantage that a glass fabric having a lower weight per unit area than a glass mat in the laminate has a higher tensile strength than a glass mat. A glass silk fabric has the additional advantage that less resin is used for the coating. As the plastics, epoxy resins, polycarbonates, polyester resins, novolak (an epoxy-based vinyl ester resin) and the like can be used.

The Indian FIG. 4 shown tank has an outer wall 21 and a leak protection lining 23. The leak protection lining is formed by a spacer sheet 11, and a spacer with the film forming a solid composite plastic layer 25, in which a glass mat 31 and at least one glass fabric 29th are incorporated as reinforcement. According to the embodiment shown, a first glass silk fabric 33 is provided only in the transition region between the bottom 35 and the side walls 37 of the tank. The first glass silk fabric 29 has an increased tensile strength (large modulus of elasticity) in the direction from the bottom to the side walls. The increased tensile strength does not necessarily have to be perpendicular to the side edges, but may also act at an angle thereto, ie the tracks may also be laid at an angle to the side edges.

Fig. 5 shows a partial view of a double-walled tank 38, in which the outer wall 21 is provided with an inner coating 39. On the inner coating 39, the metal foil 11 is applied. The metal foil 11 forms a solid composite with a glass fiber reinforced plastic layer, which is applied to the metal foil 11. The Glasfaserarmierung the plastic layer consists of a layer of glass mats and an overlying layer of a glass silk fabric (in Fig. 5 not apparent). The glass-fiber-reinforced plastic layer extends over a certain distance beyond the edge of the metal foil 11, so that an at least liquid-tight space 27 is formed between the outer wall 21 and the metal foil 11. As a conclusion, a conductive cover layer 41 is provided on the glass fiber reinforced plastic layer. This extends a certain distance beyond the edge of the glass fiber reinforced plastic layer and ensures a good seal between the leak protection lining and the outer wall.

The leak-protection lining according to the invention is produced as follows: First, a spacer-holding foil is arranged on the inside of the outer wall. The spacer sheet is applied to the inside of webs which abut against each other. To fix the webs these can be fixed with an adhesive or an adhesive tape on the outer wall. Subsequently, a glass mat is incorporated into a resin layer on the spacer sheet nationwide. After curing, resin is applied at least in the transition region between the bottom and the jacket of the tank and a first fiberglass fabric is laid. The first glass silk fabric preferably has a greater tensile strength in a given direction than in the transverse direction thereto. For this purpose, the first glass silk fabric is laid so that the increased tensile strength in the direction of the expected greater load - in the present case in the transition region from floor to wall - acts. After this step, a second fiberglass fabric is applied to the entire inside incorporated a further resin layer. Construction of a leak protection lining glass mats 300 gsm Asymmetric fiberglass fabric for sheath / floor transition 370 gsm Glass silk hybrid fabrics with carbon fibers 270 gsm resin Novolac or polyester

Exemplary embodiments of the first glass silk fabric with an increased tensile strength in the weft direction:

Embodiment 1 Embodiment 2 Fabric weight [g / m2] 370 370 Chain 6x136 tex (86g / m2) 6x136 tex (86g / m2) shot 9x300 tex (284 gsm) 4.5x600 tex (284 gsm)

Legend:

11

metal foil

13

burl

15

Base surface of the truncated pyramid

17

cover surface

19

base edge

21

outer wall

23

Leak protection lining

25

Plastic coating

27

gap

29

Glass fiber fabric

31

glass mat

33

First glass silk fabric

35

Bottom of the tank

37

Side walls of the tank

38

tank

39

internal coating

41

topcoat

Claims (14)

1. A double-walled tank or receptacle, in particular for fluids, with a tank base (35) and tank side walls (37) and with a leakage protection lining (23) which, with an intermediate space (27), is arranged on the tank base (35) and one the tank side walls (37), said leakage protection lining being formed by a spacer film (11) and at least one plastic layer (25) which is deposited on the spacer film (11) and which is reinforced with fibres,
   characterised in that
   at least in the transition region between the base (35) and the side walls (37) of the leakage projection lining, a glass mat (31) and a first glass silk fabric (29, 33) are deposited onto the spacer film (11).
2. A tank according to claim 1, characterised in that tensile strength of the first glass silk fabric (29, 33) in a first direction is larger than in a second direction.
3. A tank according to claim 1 or 2, characterised in that the first glass silk fabric (29, 33) has an unequally large number of warp threads and weft threads and is arranged such that the number of the threads running from the base (35) to the side walls (37) is larger than the threads running parallel to the side edges of the tank base (35).
4. A tank according to claim 3, characterised in that the ratio of the warp threads and weft threads is larger than 55:45, preferably larger than 60:40 and very particularly preferably > 65:35.
5. A tank according to claim 3, characterised in that the ratio of warp threads to weft threads is roughly 70:30.
6. A tank according to claim 1 or 2, characterised in that the weft threads and warp threads of the glass silk fabric (29, 33) are unequally strong and the glass silk fabric (29, 33) is arranged such that the share of threads running from the base (35) to the side walls (37), with regard to weight, is larger than that of the threads running parallel to the side edges of the tank base (35).
7. A tank according to one of the claims 1 to 6, characterised in that a second glass silk fabric (29) is deposited onto the first glass silk fabric (33).
8. A tank according to one of the claims 1 to 7, characterised in that the first and/or the second glass silk fabric (29, 33) is a hybrid fabric, which yet contains carbon fibres additionally to the glass silk threads.
9. A tank according to claim 8, characterised in that the carbon fibres are present as warp threads as well as weft threads.
10. A tank according to one of the claims 1 to 9, characterised in that a cardboard film or metal film is applied as a spacer film (11).
11. A tank according to one of the claims 1 to 10, characterised in that the plastic coating (25) is manufactured of an epoxy resin, polyester resin, novolack or a polycarbonate resin.
12. A tank according to one of the claims 1 to 11, characterised in that the spacer film (11) has nubs (13) which are designed as truncated pyramids or truncated cones.
13. A tank according to one of the claims 1 to 12, characterised in that the glass silk fabric (29, 33) is present extended over significant parts of the base (35) and/or the side walls (37).
14. A tank according to one of the claims 1 to 13, characterised in that the plastic coating (25) is manufactured of an epoxide-based vinyl-ester resin.

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