Blast shield

Abstract

 Blast shield in the form of a wall or fence consiting of one or more elements (1) or frames (2) into which is/are fixed one or more layers of perforated plates of metal (5), synthetic fibre etc. Each layer can also consist of woven cloth of metal fibre, carbon fibre, glass fibre, ceramic fibre or fibre of synthetic materials (6). The blast shield is designed to be able to absorb some part of the energy (pressure wave, heat) released by an explosion, and to permit some of it to penetrate the shield.

Description

[0001] This invention relates to a blast shield for shielding off an area with a high explosion hazard.

[0002] An area with an explosion hazard could be a pump room or an engine room in a ship, drilling rig etc., or a room in which explosives are made. It could also be a place where explosives are stored, a site where blasting is being carried out, or a complete building in which explosive materials or objects are produced.

[0003] To-day, where there is a need to shield off an area with a high explosion hazard, solid walls have been built of thick reinforced concrete, or walls in armour plate or similar material. In cases where a part of a building is to be shielded off, such walls have formed a part of the actual structure of the building.

[0004] An example is UK patent application No. 2,077,802 which discloses a wall built up of internal and external metal extrusions/sections between which there are disposed diagonal spacers in the form of plates, and in which the space between the internal and external exrusions are filled with asphalt or concrete.

[0005] All the above-mentioned types of wals are of heavy construction, dimensioned to withstand the pressure wave from a possible explo­sion. Walls of this type require solid foundations and, not least for this reason, are costly to build. This applies in par­ticular to walls of concrete. Furthermore, these cannot be used on board ship or on other floating structures on account of their weight and dimensions.

[0006] The present invention aims at furnishing a blast shield con­sisting of a wall or fence which can be made simply and at reaso­nable cost, be of a light structure, able to absorb heat radiation, and which provides good protection against the pressure wave and fragments which are thrown outwards following an explosion. A wall or fence of this type does not necessarily have to form a part of the actual building, but it must, of course, be sufficiently firmly anchored to this.

[0007] This is achieved by means of a blast shield as disclosed in the characterizing part of claim l in this application.

[0008] Expedient embodiments of a blast shield of this type are discussed in the subordinate claims.

[0009] The invention will now be described in more detail with the help of examples and with reference to the attached drawings in which:

Fig. l is a perspective drawing of a blast shield in the form of an element in a fence or wall, and

Fig. 2a, b and c are cross sections of a blast shield of this type, consisting, respectively, of one, three and five layers.

[0010] Fig. l depicts part of a blast shield according to the invention, in the form of an element l in a fence or wall. Such a fence or wall can consist of one or several layers 5, 6 of, for example:

a) woven wire of stainless steel, steel, aluminium, copper or other metals.

b) woven fibre, for example, glass fibre, carbon fibre or synthetic fibre, or

c) metal or synthetic plate with holes/openings produced by per­forating, slitting/expanding (expanded metal) or by similar techniques.

[0011] A principle feature of a blast shield of this type is that it is not intended to absorb all the energy which is released through the pressure wave following an explosion, but only parts of this. How large a part of the energy, i.e. the explosion gases/air which shall be permitted to penetrate will depend upon the material to be used, its ability to absorb deformation energy, the size of the openings in the various layers and the number of layers etc.

[0012] Each wall, or fence, is built of one or more elements l, which consist of a frame 2. Fixed in each individual frame 2, there are one or more of the above-mentioned layers. The frame 2 itself may be made of steel, aluminium or the like, and the indi­vidual layers can be attached to the frame at a fixed distance from one another by means of welding, riveting or screwing etc. It may also, in certain cases, be desirable to have the indivi­dual layers 5, 6 fixed in a controlled manner, that is to say that these layers, in the event of an explosion which exceeds a certain upper limit, instead of being splintered into pieces, break loose from the frame along some of the sides, allowing a major part of the pressure wave (energy) to pass through.

[0013] The individual elements/frames can, if expedient, have longitudi­nal or transverse ribs 3, 4 as reinforcing members.

[0014] If the wall/fence consists of a number of elements/frames, these can be fixed to one another at their outer edges (possibly by means of beams 7 etc.) with the help of suitable fixing methods (welding, screwing etc.). It can also be envisaged, for example, to arrange the frames/elements between the flanges of vertical and/or horizontal l or U sections/channels (see fig. 2c). In such cases it is particularly advantageous to make use of pre­fabricated elements.

[0015] Fig. 2b illustrates an example of a three-layer wall structure in which the openings 8 in the three layers are displaced with respect to one another, permitting vision through the wall at a certain angle a. An arrangement of this nature can be desirable for use in, for ecample, an engine room or a pump room where it is wished to separate the engines/pumps from the control unit (the control room), but where a certain amount of visual sur­veillance is possible through the wall).

[0016] Fig. 2c illustrates an example of a five-layer wall, in which three of the layers 5 consist of perforated plates, whilst the intermediate layers 6 consist of some other penetrable material, for example sound-absorbing material (metal wool, mineral wool etc.).

[0017] Other multilayer structures are also possible, both with respect to material and to the size of the openings.

[0018] The present invention thus furnishes a blast shield which is simple to build, at reasonable cost, and which affords effective protection against the pressure waves and heat produced by explosions.

[0019] As already mentioned above, such blast shields can be used on ships and oil rigs, but they are also suitable for use in buildings on land, where it is desired to shield off an area with an explosion hazard for example, production lines for explosives etc.

[0020] Blast shields according to the present invention can also be envisaged used externally in the form of fences around storage buildings for explosives, or around sites where blasting is in progress. In such cases, it is important that the fence be suf­ficiently firmly anchored to the ground.

Claims

1. Blast shield for shielding off an area with a high explosion hazard, characterized in that it is in the form of a wall or fence, which consists of one or several elements (l) comprising a frame (2) in which there is fixed one or more layers (5,6) of a heat-resisting material which permits the passage of air or gas.

2. Blast shield according to claim l, characterized in that each layer (5) consists of a cloth of metal wire; the metal being steel, stainless steel, aluminium, copper or a combination of these and other metals

3. Blast shield according to claim l, characterized in that each layer (5) consists of a metal plate with holes/openings produced by perforating, slotting, expanding (expanded metal) or similar techniques.

4. Blast shield according to claim l, characterized in the each layer (5) consists of a woven cloth or plate of fibre such as glass fibre, carbon fibre, ceramic fibre or fibre of a synthetic material.

5. Blast shield according to the above claims l-4 in which each element or frame consists of two or more layers, charac­terized in that each element or frame includes com­binations of different types of layer (5).

6. Blast shield according to claim 5, characterized in that one or more of the intermediate layers (5) consist(s) of metal wool, rock wool or similar materials (6).

7. Blast shield according to one of the claims l-5, charac­terized in that each layer (5) is firmly fixed to the frame (6).

8. Blast shield according to one of the claims l-5, charac­terized in that each layer (5) is fixed to the frame in a controlled manner, so that these will be released along one or more sides should an explosion exceed a pre-set anti­cipated value.

9. Blast shield according to one of the above-mentioned claims, characterized in that the elements can be pre­fabricated and adapted to be fixed into a supporting struc­ture, for example between the flanges (8) of U or I channels/sections on the site where the fence or wall is to be erected.

Drawing