GB922589A - Improvements relating to dampers - Google Patents

Abstract

922,589. Dampers. BABCOCK & WILCOX Ltd. July 14, 1959 [July 14, 1958], No. 22539/58. Class 51 (1). A damper having a pivotally mounted blade connected by a coupling to operating means by which the blade may be rotated to any position within a specified range, the coupling including resilient means and being such that play may occur between the operating means and the blade against the action of the resilient means which at any position of the blade in the range tends to prevent play. The blades 2, Fig. 1, of a furnace damper are pivoted within an opening 1 by a common operating bar 18 on which pins 19 are mounted for co-operating with doublearmed levers 8, 9. Each arm 8 is rigidly connected to the spindle 7 of a blade and the complementary arm 9 is freely rotatable about the spindle without significant play. Axially separated rollers 20, 20a, Fig. 5, are rotatably mounted on each pin, the arms 8, 9 being urged by a spring 17 into contact with the rollers 20, 20a respectively. The bar is reciprocated along the direction of its length by rotation of a crankshaft 21 and link 23. In the open position the arms 8, 9 firmly clamp their respective rollers on the pins so that the blades are fimly located relative to the bar and in the closed position anti-clockwise rotation of the crank-shaft moves the bar and so rotates the levers which positively grip their respective rollers under the action of the springs until each blade 2 engages projections 5a within the opening. Further rotation of each blade is impossible but each lever 9 is freely rotatable on the spindle so that further movement of the bar rotates the lever which compresses the spring and biases the blade towards the closed position to ensure a firm closure by the blale. Specification 873,524 is referred to.