Improvements in or relating to sealing means for preventing the escape of powdered flowable material from a space between relatively rotatable parts

摘要

767,000. Electromagnetic brakes and couplings. SMITH & SONS (ENGLAND), Ltd., S. March 24, 1955 [March 25, 1954], No. 8647/55. Class 35. A magnetic powder clutch or brake comprises a driving member having two annular U-shaped channel members 20, 22 embracing two annular field coils 38 and two driven members having cylindrical parts 44, 45 located in the annular space 36 of the driving member two fans 94, 96 being carried on the opposite sides of a disc 92 fixed to driving member 22. The annular space 36 contains the magnetic powder which is substantially presented from escaping therefrom by labyrinth sealing rings 72, 78, 74, 76, 80, 82 carried by the members of the clutch. Any powder escape past the sealing rings is connected in an annular chamber 120 formed between the disc 92 and the hub member 56 of the driven member 54. The powder is stopped from escaping from the chamber 120 by a stream of air circulated by the shrouded fans 94, 96 in the direction shown by the arrows. The outer fan 96 has a larger diameter than that of the inner fan 94. The clutch driven members are mounted on two concentric shafts 48, 59 separated by ball bearings 58. The hub member 84 of the clutch driving member is journalled on the shaft 48 and sealing elements 88, 90 are provided between the member 84 and the adjacent inner portions of the hub members 46, 56 of the driven members. Specification 764,949 is referred to. Reference has been directed by the Comptroller to Specification 649,553, [Group XXXIV].