Hot wind duct for large blast furnaces - where main duct is held in spring loaded straps to permit flexure

摘要

Support device for the hot wind duct on a blast furnace using a main duct which is rigidly connected to the Cowper stoves, the device using carrier beams mounted on independent supports, suspension straps being located on the carrier beams. The novelty is that the ends of the suspension straps are fixed on the carrier beams by precompressed springs, the compression force matching the wt. of the section of the duct being supported, and the initial deflection of the spring is many times the max. displacement of the duct connections occuring due to the vertical movement of the Cowper stoves. Each spring pref. consists of a stack of cup springs. The device is useful in modern blast furnaces using wind temps. up to 1400 degrees C. and duct dias. of 1700-3500 mm with Cowper stoves 6000-14000 mm dia. The spring-loaded straps permit the Cowper stove to expand and contract vertically without imposing stresses on the main duct which has a wt. of e.g. 10 t/metre.