GB1446711A - Burglar detection device - Google Patents

Abstract

1446711 Burglary detection devices J Mc- DONALD 6 Nov 1973 [10 Oct 1972] 46678/72 Heading E2X A burglary detection device comprises a thin brittle glass tube 3 containing indelible liquid, or gaseous, dye under pressure in combination with clamps 4 by which it is rigidly attached in close proximity to an interior surface of the container so that physical or thermal, shock, applied to the exterior of the container, causes breakage of the tube and drenching of its contents with dye. As shown in Figs. 1, 2, a brittle thin glass tube 3, filled with dye under pressure, is fixed in close proximity to the inside of the lid 2 of a strong box 1 by means of a pair of clamps 4 each of which has an upper element 6 which is welded to the lid 2 and a lower element 7 which is hinged at one side to the upper element 6 and is bolted thereto at the other side to encompass the tube 3 and a fibre spacer ring 8. As shown in Fig. 3, brittle tubes, interconnected by lengths of plastics, or rubber, tubing 14, are clamped in the manner shown in Figs. 1, 2, to the insides of the walls of a large safe 10 and a master cylinder 12, filled with dye fluid under pressure, is provided with a shut-off valve 13 and is connected to one of the lengths of tubing 14. Bleed valves 15 are fitted to the blind ends of two of the tubes 11 to facilitate initial filling from the master cylinder 12. A composite tube, Fig. 4, adapted to impart a directional flow to escaping dye, comprises a slotted metal tube 16 which is sealed within a filled, brittle glass tube 18. One end of the latter abuts a fibre washer 20 backed by a flange 19 welded to the tube 16, a fibre washer 21, at the other end, being backed by a coned washer 22 and a coned felt washer 23 which is compressed by a nut 24 threaded onto the end of the tube 16.