GB1367780A - Safety devices - Google Patents

Abstract

1367780 Spring power-storing mechanisms; valves COMPAGNIE FRANCAISE DES PETROLES 26 Oct 1971 49808/71 Headings F2S and F2V A device which, in the event of a breakdown in an electrical supply system, rotates a shaft 7 to close a valve (not shown) in an oil pipe-line comprises a spring mechanism 2, 3, a coupling sleeve 6 connecting the shaft 7 and the spring mechanism 2,3, a holding member 19 which holds the spring mechanism 2, 3 in its powerstored stand-by position, a solenoid 13 continuously energized by the electrical supply, and a further spring 17 compressed by the solenoid core 12 in its energized state so that, when the current fails, the spring 17 projects the core 12 against the holding member 19 to release the spring mechanism 2, 3 which rotates the coupling sleeve 6 and with it the valve control shaft 7. The spring mechanism consists of two spring units 2, 3 connected by rods 8, 9 to arms 6a, 6b extending from the coupling sleeve 6 so as to tend to rotate the sleeve clockwise. When the current fails the bell-crank holding member 19 is pivoted to release the arm 6a which then rotates under the bias of springs 23, 28 and 17. Initially the springs 23, 28 expand simultaneously, the rod 8 being braked by a dashpot formed by a piston 21 and the spring casing. Then spring 28 expands alone, until a shoulder 86 on the rod 8 abuts a bush 29 and rocks spring-biased levers 30 (normally held by permanent magnets 33) over-centre to begin the final stage of shaft rotation, which is not damped. Opening of the valve (i.e. anti-clockwise rotation of the shaft 7) charges the spring unit and locks it in the powerstored position shown.