FR2672461A1 - Shuttering device of the door type for an opening in a Faraday cage - Google Patents

Abstract

The invention relates to a shuttering device for an opening in a Faraday cage making it possible, by its design, to obtain leaktightness against electromagnetic interference. It consists of a door frame (1) having a groove, of a leaf (2) consisting of a metal skin (3) obtained by metallisation on a model given a mould-removal coating after insertion of a metal used in the metallisation, of a bonded sandwich consisting of a PVC foam (4), of a honeycomb (5), of a polyester skin (6), an inflatable seal assembly (8), strip (9), inflator (10) and installed in a groove at the periphery of the panel. When a user pressurises the inflatable seal (8), a uniform EMP contact is provided at every point of the frame (1), leaf (2), strip (9) assembly. The device according to the invention is particularly intended for shuttering the opening of EMP and ENC Faraday cages, or an NBC or EMP NBC technical shelter.

Description

 The present invention relates to a new design and embodiment of a "door" type closure device, of an opening in a Faraday cage. This shutter will be sealed against electromagnetic interference. Its design will ensure radio electric continuity.

 Up to now, Faraday's cage doors have consisted of a frame bolted to a support frame which is tightly secured to the Faraday cage.

- a leaf or opening fixed by means of hinges on the frame and receiving the closing mechanism.

 The leaf is a part made of welded sheet metal sheet metal. At its periphery is a groove allowing the interposition between the leaf and the frame of an electric radio seal of the knife or metallic knitted type.

The disadvantage of this type of Faraday cage door, - in order to obtain radio electric tightness, scrupulous compliance with the following parameters is required:
A) continuity and tightness of all welds of the sheets constituting the leaf.

B) a perfectly adjusted closing mechanism to obtain the necessary crushing of the joint.

C) the most perfect geometry of the frame and leaf assembly.

 The device according to the invention eliminates the drawbacks mentioned above, namely: - the leaf will be made up * of a metal skin produced by metallization, by means of flame guns or electric arc SNMI (registered trademark), METCO ( registered trademark) or TAPA (registered trademark), on one model; plaster release, reproducing the finished part.

 In this metallization will be embedded a metal deployed to ensure the electrical continuity function. The process eliminates all welding, it is waterproof by construction.

A PVC foam composite panel will be glued to the metallization,
Honeycomb, and polyester skin to perform isothermal, mechanical and aesthetic functions.

 The radio electric tightness will be achieved by the interposition of a metal blade mounted on the periphery of the leaf and fixed on an inflatable seal.

 The inflatable seal ensures, once pressurized, a permanent and homogeneous contact of the blade between the leaf and the frame, whatever the geometric and mechanical faults of the leaf frame assembly and of the cremone hinge closure system.

 The pressure in the seal is obtained by injecting gas by means of a manual or motorized pump, a workshop distribution circuit or a pressurized capacity.

 The support groove of the blade in the frame has a contact angle different from 900, which gives the contact forces when it is pressurized.

This decomposition of the forces generates lateral movements of the blade on its support, or a friction which ensures uni-self-cleaning of the contacts over repeated openings and closings.

 Different embodiments can be applied to this invention - the composition of the swing panel can be varied depending on the environment where the door is installed.

Kevlar skin can be stuck outside if; impact resistance is necessary, a decontaminable resin skin can be substituted if the environment requires.

- A seal groove can be made in the field of the panel to receive another inflatable seal which will provide a function, watertight, - to nuclear contamination to biological or chemical attack depending on the nature of the material of the seal mounted .

- The support blade will be a sheet of metal folded to the forms allowing to obtain optimal contact surfaces. But it can also be produced by mass machining with more massive shapes.

- The frame will be a steel plate machined in the mass, but it can be made according to the same principle as the leaf. That is to say: * Realization of a wood or resin model * Application of release agent * Realization of a metallic skin by flame or electric arc metallization.

* Insertion of an expanded metal in the metallization * Stratification of glass fabrics and resin to obtain the mechanical inertia of the assembly.

The accompanying drawings illustrate the invention:
Fig n01: sectional representation of the device according to the invention.

Fig n02: sectional representation of a variant of the invention.

 Referring to figure nolr, the device comprises a frame (1) which will be metallic and made of a material which is electrically conductive (cupro'alu stainless steel or tinned aluminum), of a leaf (2) composed of a metal skin (3 ) obtained by metallization on release agent with insertion of the metal deployed in this metallization, of an isothermal foam (4) bonded to the metal skin, a honeycomb (5) bonded to the foam and a polyester skin (6) bonded on the honeycomb.

High density foam (7) is glued to the periphery of the panel and closes the field.

 In an groove around the panel is the inflatable seal (8) equipped with its inflator (10). The metal contact blade (9) is glued to the inflatable seal and slides in the groove.

Once the seal is inflated (8), the blade (9) slides in the groove of the swing panel (2) and presses on the frame (1) also closing the electric field. The current will flow through the skin (3), the contact of the blade (9) and the frame (1).

For figure 2 the realization breaks down as follows:
The frame is made according to the same technique as the leaf, that is to say metallization on mold release with insertion of expanded metal and stratification of the metal skin with a glass and resin fabric.

The composition of the leaf (2) can be adjusted according to the climatic, mechanical or chemical parameters which it will have to undergo.

 The metallic skin (3) will always be of the metallization-on-release type on which a honeycomb (5) will be bonded for mechanical resistance and a kevlar skin (6) for resistance to impacts.

 In the leaf field (7) is made a groove which receives an inflatable seal (11) having a sealing function against water and the external atmosphere.

 This seal (11) is connected by a conduit (12) to the inflator (10) of the main seal (8) so the pressurization of the inflator (10) will allow the inflation of the seal (8) and (11) simultaneously performing the atmospheric and radio electric tightness. A second inflator (13) enables the joints to be pressurized or depressed by the inner side of the leaf.

 In this version, the blade (9) is a part produced by machining.

Claims (6)

 1) The “door-type” obturation device for an opening in a Faraday cage, characterized in that it comprises a dor-mantle (l) having a groove, a leaf (2) consisting of a metallic skin ( 3) metal composite sprayed onto a model coated with release agent, with the insertion of expanded metal, a Pvc foam sandwich (4), honeycomb (5), polyester skin (6) of a panel field fertilized by high foam density receiving an inflatable seal (11) equipped with a supply pipe (12), which, when pressurized, seals against external atmospheres / of a metal blade assembly (9) fixed on an inflatable seal (8 ) equipped with an inflator (10) which, once pressurized, ensures radio electric continuity between the frame (1) and the leaf (2).  2) The device according to claim 1 characterized in that the metal skin (3) of the leaf (2) is obtained by applying the following technique: - production of a model - application of a release agent on the model - projection of metal on the release agent by means of a hot spray gun - insertion at the time of projection of a metal deployed in the skin thus formed  3) The device according to claim 1 characterized in that the composite panel bonded to the metal skin (3) can be adapted by its composition to the environment in which it will be installed.  The standard composition will be as follows - 1 PVC foam (4), - 1 honeycomb (5) - 1 polyester skin (6).  4) The device according to claim 1 characterized in that a constant contact pressure is applied at all points of the frame assembly (1) leaf (2) and blade (9). This constant pressure is obtained by the use of an inflatable seal (8).  5) The device according to claim 1 and 4 characterized in that the contact surface of the blade (97 on the frame (1) is inclined which allows self-cleaning of this contact surface by a lateral movement of the blade.  6) The device according to claim 1 characterized in that a second inflatable seal (11) can be mounted in the field (7) of the leaf (2) and pressurized simultaneously with the first seal (8).