METHOD OF HEAT TREATMENT OF ARTICLES AND PLANT FOR ITS REALIZATION Russian patent published in 1995 - IPC

FIELD: metallurgy. SUBSTANCE: articles are introduced into thermal zone at preset temperature field where they are moved over zigzag trajectories with parallel horizontal branches in height, after which they are removed from thermal zone. During removal, curvilinear temperature field is created with maximum at center portion and minimum at upper and lower edges; articles are moved in two flows over two zigzag trajectories whose horizontal branches are alternating in height forming at least six tiers; articles are introduced and removed at tiers located at upper and lower edges of thermal zone in such way that introduction and removal of articles of different flows are effected at one edge of thermal zone and introduction and removal of articles of one flow are effected at opposite edges. Created vertically inside thermal zone is curvilinear temperature field symmetrical relative to central horizontal plane. Removal of articles is effected over extreme tiers and introduction of articles is effected over tier adjacent to extreme ones which is shifted towards central portion. Articles are moved over zigzag trajectories number of horizontal branches of these trajectories is multiple of two. Inlet and outlet of articles of different flows are located on one side of central vertical plane. Plant for heat treatment of articles consists of multi-tier heat- insulated chamber with heating elements, devices for transfer of articles from tier to tier, pushers with drives and loading and unloading devices. At least six tiers are provided. Tiers are made in form of longitudinal guides mounted on transverse ceramic tubes inside which (at least on one tier located in central portion) heating elements are arranged; transfer device is made in form of two stages arranged on either side of tiers; pushers are secured on vertical beams connected with drive; they are shifted vertically relative to one another by at least one pitch between tiers. EFFECT: enhanced reliability. 6 cl, 5 dwg