n TECHNICAL FIELD

The present invention relates to a shock wave-absorbing gastight lead-through for one or more conduits through a building component, e.g. an air-raid shelter wall.

BACKGROUND ART

Large demands are made on conduit leads-through in air-raid shelter buildings 5 in respect of the ability to withstand pressure and shock waves coming from explosions. Since, in a state of war, different forms of the war gases can come into use, complete gas tightness is, inter alia, required to be maintained in a lead-through even during and after it has been subjected to shock waves with a pressure of up to 50 bar. The lead-through shall also be fire- and water-proof.

10 A plurality of different forms of lead-through for air-raid shelters are in use, all having the common feature that they include heavy pipe stubs or steel frames, usually provided with flanges for engaging against the exterior of the building component and intended for being cast into the floor, wall or roof of such buildings. There are leads-through for single conduits as well as bunches of

15 conduits comprising a limited number of conduits. After laying the conduits, the pipe stubs are filled with some kind of casting or moulding compositon and at their ends they are provided with tightenable elastic seals or threaded details. Furthermore, a conical termination of the lead-through is arranged outside the pipe stub round the conduit or bunch of conduits led through, with the object of

20 deflecting Shockwaves. In the case where it is a question of leading through a bunch of conduits, the space between the conduits must be filled out with a s sealing agent. Later supplementation with further conduits through an already utilized lead-through is not possible, shelter structures therefore requiring careful planning of conduit requirements as well as requiring spare leads- 25 through to be cast-in for future needs.

The use of these known leads-through involves large costs, since in themselves

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they are expensive, due to their robust fabrication, added to which they are expensive to handle, since they are difficult to locate in the shuttering when pouring the concrete for the building components of a shelter, and they also require sealing and filling with composition after laying the conduits. Further to this there is required, as already mentioned, a number of spares for possible future use, which must be already cast into the building components of the shelter from the beginning. Since the leads-through only cater for one or a few conduits, the need of leads-through increases, causing an undesired spread-out over a building component of the conduits required for a shelter.

In summary it may be said that the known devices are based on the use of robust, resistent and well-anchored lead-through devices.

DISCLOSURE OF INVENTION

The present invention has the object of reducing the costs for conduit leads- through preferably for air-raid shelters, said object being achieved by the lead- through itself being considerably simplified, by the method of laying conduits having been made less laborious, by enabling laying more conduits per lead- through and by eliminating the need of spare leads-through. This is achieved by the lead-through in accordance with the invention having been given the characterizing features disclosed in the following claims.

The invention will now be described with reference to the accompanying drawing, on which an embodiment is illustrated.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a cross section of a building component having a through hole in which is placed a lead-through with a conduit.

Figure 2 is a plan view of a stop plate with clamping means intended for placing in a through hole and

Figure 3 is a section of a portion of the stop plate with clamping means.

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BEST MODE FOR CARRYING OUT THE INVENTION

In Figure 1, illustrating in cross section a building component 1 with a through hole 2 made afterwards, a prefabricated elastic body is denoted by the numeral 3 and is preferably of fire-proof foamed material, this body being inserted in a hole under compression in a manner described in the Swedish Patent 8102688-2. The body 3 is placed on the left-hand side of the building component, which is assumed to be the pressure side, i.e. the side which may be subjected to a shock wave, symbolized here by a number of arrows. A stop plate 4 is also placed in the hole, and clamped into engagement against the side of the elastic body facing away from the pressure. A conduit 5 is laid through a hole 10 in the plate 4 and through the elastic body 3. The conduit 5 has been passed through the body 3 and plate 4 with the aid of a tubular tool having a removable tip, the tool having been driven through the body and having been removed after laying the conduit, after which the compressed foamed material elastically returned into sealing engagement against the conduit.

The task of the stop plate 4 is to prevent the elastic body 3 from moving in the hole 2, and for this purpose it is provided with some kind of fixing means. One embodiment of a clamping means is illustrated in plan view and section in Figures 2 and 3, respectively, together with an stop plate 4. The stop plate 4 has the shape of a truncated cone, and round its circumference there are six segments 6 having a cuneiform cross section and accommodating to the cone surface. The segments are kept in place by a spring wire 7, running in a groove in the segments, and by a pressure ring 8. The pressure ringe 8 is loosely attached to the plate 4 with the aid of a plurality of screws 9, and when they have been tightened up and the end plate is in place they press the segments 6 outwards and cause them to engage against the wall of the hole.

Since the elastic body 3 is located nearest the pressure side, should there be an explosion it will absorb and dampen the shock wave before the latter reaches the stop plate 4, and therefore the demands on the fixing means and required clamping force of the stop plate are considerably less than if the stop plate had been directly hit by the shock wave. During the short moment when the shock wave hits the elastic body, the latter is pressed against the wall of the hole as well as the sheath of the through conduit, for thereby automatically increasing

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the seal during the most critical moment.

Instead of making the hole 2 afterwards, a prefabricated elastic body provided with a jacket can naturally be cast into the building component, as is illustrated in the Swedish Patnet 8002044-9. In the case where the jacket is corrugated, the fixing means of the stop plate can be formed with means gripping in the corrugations.

The heavy steel muffs, with sealing compositions and tightenable sealing means in the form of screwed details and the like, are entirely eliminated by the present invention. Furthermore, the number of leads-through may be reduced and the conduits better concentrated, since each lead-through allows the passage of a greater number of conduits. Later laying of conduits in already utilized leads-through is also possible.