HOT AIR CIRCULATION TYPE HEATING FURNACE

摘要

PROBLEM TO BE SOLVED: To provide a safe hot air circulation type heating furnace superior in durability by preventing fractures of a furnace casing caused by the thermal expansion difference between an inner wall and an outer wall. SOLUTION: This invention comprises a cylindrical inner wall 2 surrounding a heating chamber 7 for accommodating a heated material together with covers 5, 6 provided to both longitudinal ends; a cylindrical outer wall 4 surrounding the inner wall 2 and forming an air passage 3 between this wall and the inner wall; and a blower 24 and a heater 10 circulating the hot air in the air passage 3 as circulation flow. The outer wall 4 is provided with a thermal expansion absorbing part (bellows ring 8) absorbing the longitudinal thermal expansion difference between the outer wall and the inner wall 2. COPYRIGHT: (C)2003,JPO