GB930063A - Improvements in, or relating to, annealing furnaces - Google Patents

Abstract

930,063. Annealing furnaces. STEEL CO. OF WALES Ltd. July 10, 1959 [July 10, 1958], No. 22124/58. Class 51 (2). A coil annealing furnace comprises one or more upwardly extending bases each of which is associated with a heat exchanger located externally of the furnace and provided with at least one inlet pipe and at least one valve controlled discharge pipe, the pipes extending through the base, and an open end of the inlet pipe disposed in a diffuser duct so that, on the commencement of cooling, a proportion of the gaseous atmosphere flows through the heat exchanger where it is cooled and then returned to the furnace. As shown, a furnace hearth 1 has a raised base 2 having a hollow plate 3 supporting a diffuser comprising two superimposed annular plates 4, 5 secured together by spacer bars 6 and having openings 4a, 5a. The diffuser also comprises a system of blades secured to the underside of the plate 4 and a fan is disposed in a central opening. A heat exchanger 18 is located below the hearth and is provided with an inlet pipe 19 and a discharge pipe 20, the latter having a valve 21. Coils 22 for annealing are placed on the plate 5, the cover 24 sealed in position, and the temperature raised. When the heating is completed the valve 21 in the discharge pipe is opened with the result that a proportion of the hot gases passes through the heat exchanger, is cooled, and returned to mix with the remainder of the atmosphere and the cooling of the coils is expedited. In a modification, Fig. 4 (not shown), a single plate 5 is used and in a further modification, Fig. 6 (not shown), the position of the outlet of the discharge pipe is altered.