The present invention concerns a wall through connection for a ventilation duct system, where the wall through connection is capable of resisting high temperatures. Preferably, the whole ventilation duct system in which the wall through connection is a part of also withstands high temperatures.

There are classifications for the possibility of withstanding high temperatures for wall through connections. Our aim is to provide a wall through connection which when arranged in a through hole in a wall will fulfil at least fire class A2-sl-d0. For example, the wall through connection must not exceed an energy content (PSI value) of 3 MJ/kg in order not to add energy to a possible fire. At the moment both wall through connections and steel ducts are arranged in buildings, which thereafter are provided with mineral wool to insulate the ducts. The mineral wool is usually attached by means of chicken wire around the ducts and mineral wool.

The aim is also to provide a pre-insulated wall through connection which will be both easily handled and lightweight.

The ducts connected to the wall through connection may be standard ones present on the market, preferably fulfilling the European classification below. Most preferred is our ventilation duct system which will reach the market after the filing of the present application and which is presented in the still non-published patent applications 2151233-0, 2151234-8 and 2151235-5, comprising a fibre layer and an inner layer surrounding a flow space. The fibre layer comprises mineral fibres and a binder, compressed into a desired duct shape and the inner layer is a steel foil having a thickness of 0,01-0,3 mm, facing the flow space. The mineral fibres should have a melting point over 800 degrees Celsius. In the classifications for the possibility of withstanding high temperatures for ducts, the ducts transfer flue gas and must withstand temperatures between 900 and 1000 degrees Celsius for at least half an hour or at least an hour to fulfil a European classification EN1366 according to EI30/60. This will give people time to evacuate a burning building. According s to this classification the cross section must be intact, and the outside temperature of the duct must not exceed 140 degrees Celsius in average and not over 180 degrees Celsius in one point.

Summary of the invention w According to a first aspect of the invention a wall through connection comprising a duct portion having a fibre layer and an inner layer surrounding an elongated flow space, wherein the fibre layer comprises mineral fibres and a binder, compressed into a desired duct shape, the mineral fibres having a melting point over 800 degrees Celsius, and is - the inner layer is a steel foil having a thickness of at least 0,01 mm, facing the flow space. For example, the foil thickness could be 0,01-0,3 mm, preferably 0,01-0,2 mm and most preferred 0,03-0,1.

At least one of either a first sleeve couplings or a second sleeve coupling are arranged on0 opposite sides of a wall having a throughgoing hole which shall receive the wall through connection.

Each first sleeve coupling has a first flange, orthogonal to a length axis along the elongated flow space, for connection to respective side of the wall and a rim portion more or less5 parallel with the length axis, facing away from the wall when arranged. The rim portion provides a radial stop for an expanding fire sealing material which is provided in between an outer surface of the duct portion and the rim portion of the first sleeve coupling when arranged in the thronging hole. A second orthogonal flange reaches from the rim portion inwards to the outer surface of the duct portion providing an axial stop for the fire expand-0 ing sealing material. Each second sleeve coupling has an orthogonal flange and a sleeve protruding into the throughgoing hole covering up to half of the depth of the throughgoing hole in the wall when being in position in the throughgoing hole. Expanding fire sealing material is provided between the sleeve of the second sleeve coupling and the outer surface of the duct portion.

This solution provides a sealed yet flexible wall through connection which easily may take up movements of a wall during a fire but still keep the wall through connection sealed so that no flue gases will leak from one room to another. Due to heat expansion walls may expand up to at least 50 mm. The wall through connection is pre-insulated, which minimises the need of separate transports and additional work at the installation place, and lightweight. Further, the wall through connection is also sound dampening. Obviously, the present invention may also be used through a floor/ceiling.

According to some embodiments of the wall through connection, both a first sleeve cou- pling and a second sleeve coupling are provided on each side of the wall. The second sleeve coupling is preferably attached between the first sleeve coupling and the wall on each side of the wall and the flange is positionable between the first flange of the first sleeve coupling and the side of the wall. This embodiment provides more sealing. According to some embodiments of the wall through connection, two cuffs are provided one on each side of the wall covering the sleeve coupling, the cuffs are made of mineral fibres having a melting point over 800 degrees Celsius and a binder, compressed into a desired cuff shape. This embodiment provides more heat insulation. According to some embodiments of the wall through connection, an outer layer is provided on the outside of the fibre layer. The outer layer comprises an aluminium foil and a polyethene layer for attachment to the fibre layer. This make the duct portion easier and safer to handle since the fibres are encapsuled inside the outer layer. According to some embodiments of the wall through connection, the steel foil is a stainless- steel foil. This protects the ducts from corroding and increase the heat resistance.

According to some embodiments of the wall through connection, the fibre layer is self-sup- ported.

According to some embodiments of the wall through connection, the mineral fibre length is at least 10 mm, preferably at least 20 mm or at least 30 mm. Due to the long fibres the compressed fibre layer will stay intact also after the binder is burnt out.

According to some embodiments of the wall through connection, the binder is phenolic based and water soluble.

According to some embodiments of the wall through connection, the ventilation duct lacks binding material between the fibre layer and the inner layer. This keeps the energy level low in the ventilation duct, which keeps the temperature down in the duct.

According to some embodiments of the wall through connection, the cross-sectional shape of the duct portion is more or less circular.

According to some embodiments of the wall through connection, stiffening means are present at the inner layer. Thus, a support to withstand the pressure from the expanding fire sealing material is provided, for example. Preferably, according to some embodiments of the wall through connection, at least one stiffening means is provided in line with the fire expandable sealing material.

According to a second aspect of the invention a method of mounting a wall through connection comprising a duct portion having a fibre layer and an inner layer of steel foil is provided. A binder solution is sprayed on the fibre layer, whereafter the fibre layer is com- pressed into a duct shape, having an elongated flow space, under heated conditions so that water in the binder solution evaporates, and the inner layer is brought into the flow space of the duct, which inner layer seals the flow space of the duct from the fibre layer. Thereafter, bring the duct portion into a throughgoing hole in a wall. Mount at least a first sleeve coupling or a second sleeve coupling on opposite sides of the wall by attaching either a first orthogonal flange to the side of the wall and positioning expanding fire sealing material between a rim portion of the first sleeve coupling and an outer surface of the duct portion or by attaching an orthogonal flange and positioning a sleeve into the throughgoing hole covering up to half of the depth of the throughgoing hole in the wall, and positioning expanding fire sealing material between the sleeve of the second sleeve coupling and the outer surface of the duct portion.

According to some embodiments of the mounting method, both a first sleeve coupling and a second sleeve coupling are provided on opposite sides of the wall, whereby the second sleeve coupling is situated between the first sleeve coupling and the wall on each side of the wall. The second sleeve coupling has an orthogonal flange positionable between the first flange of the first sleeve coupling and the side of the wall.

According to some embodiments of the mounting method, stiffening means are provided at the inner layer, at least in line with the expanding fire sealing material. Thus, in case of fire, the expanding fire sealing material expands and will compress the fibre layer so that no flue gas may leak through the compress fibre layer.

According to some embodiments of the mounting method, two cuffs are positioned, one on each side of the wall, covering the sleeve coupling. The cuffs are made of mineral fibres having a melting point over 800 degrees Celsius and a binder, compressed into a desired cuff shape.

Short description of the drawings

The present invention will be described in more detail under referral to the drawings, in which Fig. 1 shows a wall through connections present in a throughgoing hole of a wall according to an embodiment of the invention in a cross-sectional view. Fig. 2 shows an exploded, perspective view of the embodiment of Fig. 1.

Detailed description of embodiments of the invention

In Fig. 1 an embodiment of a wall through connection having a duct portion 1 comprising a s fibre layer 2 and an inner layer 3 surrounding an elongated flow space 4 is shown. The cross- sectional shape may be any suitable shape. A through going hole 9 is present in a wall 13 which is to receive the wall through connection. The throughgoing hole 9 may have the same cross-sectional shape as the duct portion 1. Preferably the throughgoing hole 9 is larger than the duct portion 1. In the shown embodiment the duct portion 1 has a circular w shape. A thought length axis 14 is going through the flow space 4 along the length of the duct portion 1 and it has two open ends 12. The duct portion 1 is provided inside the throughgoing hole 9 and attached according to below. Other pieces of a ventilation duct system are positionable at the two open ends 12. is The fibre layer 2 is built up by mineral fibres being compressed with a binder. The mineral fibres should have a melting point over 800 degrees Celsius. The fibres may have a length of at least 10 mm, preferably at least 20 mm or at least or 30 mm. In one embodiment the fibre fulfils the classification RAL/40. 0 The mineral fibres are sprayed with a binder solution, which preferably is based on a water- soluble phenolic resin. Thereafter the mineral fibres are compressed and heated in a form to reach its final shape. During the compression and heating the water in the binder solution evaporates and the phenolic resin cures at a temperature around 200 degrees Celsius. The amount of binder solution before the forming procedure, i.e., the compression and heating,5 is between 1-5% by weight. The amount of binder is kept to a minimum in order to avoid adding too much energy into the wall through connection, which energy would increase the temperature in case of fire. It is also conceivable to use other binders than phenolic based.

After the compression and heating step of the fibre layer, the fibre layer is stiff enough to0 be self-supported so the duct portion 1 is self-supported. The inner layer 3 is a steel foil having a thickness of at least 0,01 mm, for example 0,01-0,3 mm, preferably 0,01-0,2 mm and most preferred 0,03-0,1. In one embodiment the steel foil is a stainless steel foil. As an example, AISI 304 may be a suitable steel. s According to the embodiment in Fig. 1 the duct portion 1 comprises a fibre layer 2, an inner layer 3 and an outer layer 5. The outer layer 5 comprises at least an aluminium foil and a layer of polyethene. The amount of aluminium may be 15-25 gram/m ² . The amount of polyethene may be 10-50 g/m ² , preferably 15-30 g/m ² . However, the outer layer 5 is optional. w The outer layer 5 comprises a layer of polyethene closest to the fibre layer 2. The polyethene layer functions as a binder and will stick to the fibre layer 2 by a heating step during production where the polyethene melts and thus bonds the outer layer 5 to the fibre layer 2. Outermost is a layer of aluminium provided. In between a mesh, net or spread glass fibres may be provided. The layer of glass fibres would increase the strength of the outer layer 5. is Preferably, the aluminium is black on its outside, which promote heat dissipation. Generally, the outer layer 5 is arranged to enhance the look of the ventilation duct and to encapsule the fibres, which increases health standards when working with the wall through connection and the possibility to keep it clean. 0 As an example, the production of the inner layer can be described. Preferably, two sheets of steel foil may be provided one on top of the other. Along long side edges the steel foils are joined by means of welding, such as seam or spot welding or riveting. It is also possible to unite by means of folding. If needed it is possible to provide sealing material in the joint between the two steel foils. This could for example be expandable fire sealing material.5

After uniting the two steel foils they are raised, for example by means of suction on opposite outer sides of the steel foils under a movement away from each other, so that a flow space 4 is formed. 0 The inner layer 3, for example provided according to above, may be drawn into a self-sup- ported fibre layer 2, provided with an outer layer 5 or not. Preferably, the two joints between the two steel foils cut a short distance into the fibre layer 2. When drawn into place the inner layer 3 may be finally shaped into the shape of an inner space of the fibre layer 2, for example by pressing mandrel having a shape corresponding to the inner space of the fibre layer 2 along the length of the duct portion 1.

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Preferably, there is no binding material between the fibre layer 2 and the inner layer 3. In this way the total energy content of the wall through connection can be kept low. However, an inorganic adhesive is conceivable to fix the inner layer 3 against the inner side of the fibre layer 2. w

The duct portion 1 is attached at the wall 13 with at least one set of either a first sleeve couplings 6 or a second sleeve coupling 8. The set comprises two pieces of sleeve couplings arranged on opposite sides of the wall 13. Between each sleeve coupling and an outer surface of the duct portion 1, provided with or without an outer layer, an expandable fire seal- 75 ing material 7, 21 is present. If a fire starts the expandable fire sealing material will expand by the heat and thus effectively seal so that no flue gases may penetrate.

Each first sleeve coupling 6 has a first flange 15, orthogonal to the length axis 14 along the elongated flow space 4, for connection to respective side of the wall 13. The connection0 could for example be provided by means of screws 22, rivet or the like. A rim portion 16 more or less parallel with the length axis 14, facing away from the wall 13 when arranged, provides a radial stop for an expanding fire sealing material 7 provided in between the outer surface of the duct portion l and the rim portion 16 of the first sleeve coupling 6. A second orthogonal flange 17 reaching from the rim portion 16 inwards to the outer surface of the5 duct portion 1, providing an axial stop for the fire expanding sealing material 7.

Each second sleeve coupling 8 has an orthogonal flange 19 and a sleeve 20 protruding into the throughgoing hole 9 covering up to half of the depth of the throughgoing hole 9 in the wall 13. Expanding fire sealing material 21 is provided between the sleeve 20 of the second0 sleeve coupling 8 and the outer surface of the duct portion 1. The wall through connection must have one of the first 6 or second 8 sleeve coupling on each side of the wall 13. However, the opposite sides may have different sleeve couplings. In order to provide an even more temperature resistant wall through connection at least one side has both a first sleeve coupling 6 and a second sleeve coupling 8, wherein the s second sleeve 8 coupling is attached between the first sleeve coupling 6 and the wall 13 on each side of the wall 13. An even better solution is to have both sleeve couplings 6, 8 on both sides of the wall 13.

In case of fire, the expanding fire sealing material expands but cannot expand outwards due w to the rim 16 and sleeve 20, respectively. Thus, it will expand inwards and will compress the fibre layer against the inner layer 2 so that no flue gas may leak through the compress fibre layer. It is advantageous to have stiffening means at the inner layer 2 in order to safeguard against the inner layer 3 collapsing during a fire when the expandable fire seal material expand, at least if the inner layer 2 is very thin.

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This could be achieved, for example, with one or more bands 10 of sheet metal provided on the inner side, facing the flow space 4, of the inner layer 2 transversely to the length of the duct portion 1. The band or bands may have a suitable width for the wall through connection. 0

In Figs. 1 and 2 both sleeve couplings 6, 8 are arranged on opposite sides. Further, three bands 10 are arranged along the portion of the duct portion 1 corresponding to the expandable fire sealing material 7, 21. A cuff 23 may be arranged over the at least one sleeve coupling on each side of the wall 13 in order to further enhance the heat resistance of the wall5 through connection. Preferably the cuff comprises mineral fibres and a binder, compressed into a desired cuff shape that can enclose the at least one sleeve coupling. The mineral fibres have preferably a melting point over 800 degrees Celsius.

The joint between the cuff 23 and the wall 13 and the duct portion 1, respectively, may be0 provided with a sealing 24, preferably an expandable fire sealing material. It is possible to reinforce the open end 12 of the duct portion 1 with a stiffening means 11, such as a metal flange.