| 摘要 |
The invention relates to a device for protecting an air-passage orifice (1). It comprises a plurality of steel tubes (2, 3) which are arranged in the longitudinal direction of the air-passage orifice (1) and which bear against one another so as to fill the cross-section of the air-passage orifice (1). The steel tubes (2, 3) are combined in bundles in at least two zones (Rz1 and Rz2) offset relative to one another in the longitudinal direction of the air-passage orifice (1). The device achieves a high resistance-time value against a wide variety of break-in means. A sufficiently large air-passage region for the supply and discharge of air along with a low flow resistance, is nevertheless provided. As a result of the division in two zones (Rz1 and Rz2) which are offset relative to one another and which are mutually separated from one another by transversely directed lattice-like or grid-like intermediate walls (4, 5), the resistance-time value is increased even further. Even if one zone (Rz1 or Rz2) is damaged, the other zone still affords sufficient protection for the period of time within which security guards are alerted. The zones (Rz1 and Rz2) can be spaced from one another by means of a slatted-grid zone (L2) having inclined guide elements (6). <IMAGE>
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