(under subclass 363) Devices for closing and opening the sifting passages of sifters to render the sifters inoperative as such or bring them into operation.
(1) Note. This subclass does not include means intended
primarily to adjust or vary the size of sifting passages.
SEE OR SEARCH THIS CLASS, SUBCLASS:
376, for sifters associated with coal hods or ash pans.
394, 398 and 402, for sifter passage structure which has adjustable openings.
SEE OR SEARCH CLASS 241, Solid Material Comminution or Disintegration
89, for comminutors combined with adjustable screens.
