GB332436A - Improvements in or relating to annealing furnaces - Google Patents

Abstract

332,436. Kenworthy, C. F. Jan. 14, 1929, [Convention date]. Resistance furnaces.-Apparatus for annealing metals in a non-oxidizing atmosphere comprises an open-bottomed furnace 17, heated by electric resistance elements 25b, and a series of magazines or containers 32 for the charge 34a arranged below the furnace and adapted to be moved in turn into alignment therewith, a sealing-ring 30 being provided for maintaining a gas-tight joint between the furnace and magazine during the raising of the metal into the furnace, the heating operation, and its return to the magazine. The latter is formed at its upper end with a sealing-trough 44 divided by a partition 45 into an outer compartment 47 for engagement with the ring 30 and an inner portion 46 with which co-operates a cover 48 adapted to rest on vertical rods 51 and be raised and lowered with the charge 34a. The bent-over upper end of the sealing-ring 30 engages in a trough 29 formed around a flange 26 depending from the furnace bottom, the ring being vertically movable, by a system of links 77, 84, operated by a handle 80, to allow positioning and removal of the magazine. The charge 34a is raised from and lowered into the magazine by a platform 50 with which engages the head 53 of a hydraulic ram 52, communication with the atmosphere being prevented, when the ram is raised, by the co-operation of the depending flange 33 and water contained in the shallow pit 11. To indicate when the charge has reached the fully raised and fully lowered positions, a vertical tell-tale rod 72 is operated by a pivoted lever 67, having on its inner end a projection 73 adapted to contact with the ram head 53, and connected to the head 53 by a chain 74. The magazines are mounted on a turntable 36, 40 which is automatically locked, when a magazine comes into position below the furnace, by the engagement of a slotted lever 59, pivoted to a fixed bracket 58, over a stud 63 provided on the turntable frame 36. The locking device is released, when the, magazine is to be moved away from the furnace, by operating a handle 60 to raise the lever 59. Prior to the raising of the charge into the furnace, the air in the magazine is driven out through a valve 95 by steam delivered by a pipe 94, and during the annealing operation steam is continuously supplied to the furnace 17 through a. pipe 22a, the excess vapour escaping through valve 23. The cooling of the .treated charge in the magazine after the latter has been moved away from the furnace, is effected first by supplying steam through the pipe 94 and finally by spraying water on to the outside of the magazine. Immediately before the spraying commences, a valve 90 in a pipe 91 connecting the magazine with the furnace 17 is opened, the formation of a vacuum in the magazine being thus prevented. A modification is described in which the magazines, instead of being mounted on a turntable, are carried on wheeled carriages which run on a straight track located directly below the furnace. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a construction in which the magazines themselves are raised, with the enclosed charges, into the furnace, the sealing ring 30 being in this case omitted. This subject-matter does not appear in the Specification as accepted.