GB1096461A - Vibration damping means - Google Patents

Abstract

1,096,461. Vibration dampers; expansion joints; flexible tubes. ENGLISH ELECTRIC CO. Ltd. Nov. 30, 1965 [Dec. 1, 1964], No. 48720/64. Headings F2G, F2P and F2S. Vibration damping means for a metal expansion bellows 10 used for joining two pipes, not shown, e.g. for a main CO 2 coolant gas in a nuclear reactor, comprises a number of ring tubes 13 of resilient material such as rubber, each of the tubes being filled with a granular material, e.g. sand or vermiculite, and lodged in a groove 12 in the bellows. If the latter is of helical form a continuous tube is provided for each start of the helix. To prevent shifting of the sand along the tubes each of the latter is provided with a number of circumferentiallyspaced plugs. In a modification, Fig. 2 (not shown), the tubes 13 are omitted, sand being trapped in the grooves 12 by a silicone rubber sleeve (20) stretched over the bellows. In a further modification, Fig. 3 (not shown), a bellows (10), connected to gas ducts (31, 31) is sealed in a box (33) having a flexible bellows portion (34). The space in the box 33 above a wire mesh screen (36) is filled with sand (39) and, when compressed air is fed to an inlet (37), through the sand to an outlet (38) with a filter (40), the sand behaves as a fluidized bed. The damping effect of the latter can be varied by changing the compressed-air flow. Vermiculite or graphite can be used instead of sand. Instead of providing the box (33) with the bellows portion (34) it may be arranged to slide axially on the ducts (31, 31).