Abstract: An apparatus for detecting a break in a screen of a vibratory separator includes an infeed section coupled to the housing such that at least a portion of the material passing through the screen and directed from the housing is directed through the infeed section, a detector screening element receiving material from the infeed section, wherein the detector screening element has a plurality of openings having a size equal to or slightly larger than the opening size of the screen in the vibratory separator, and a level sensor positioned above the detector screening element, wherein the level sensor is positioned to detect material build up on the detector screening element.

Abstract: A sifter having a resiliently mounted housing with horizontal vibrated screens. Airborne material to be sifted is introduced between the screens where it is deflected by a deflector and a breaker ring to distribute material both upwardly and downwardly to the screens. An external passage from above the upper screen conveys air and material to a discharge pipe below the lower screen and below a bottom pan which feeds into the distribution pipe. An extended passage for discharging oversize material from between the screens is open along its length to the lower screen. A weir at the inlet of the extended passage has a thin slit below and a larger hole above to allow material under certain conditions to flow into the outlet passage.