Abstract: This describes an automatic defect inspection system as could be applied to metallized masks or other patterns. The system causes each subfield to be individually aligned for inspection irrespective of the previous alignment of the pattern or any other sub-field. This is accomplished by scanning a preselected portion of each sub-field and adjusting the position of the scan based on the resulting signal while scanning a pre-established portion of the sub-field. In this way a portion of each sub-field is used as an alignment mark and stepping errors avoided.Once alignment is achieved a probe, comparable to the size of the minimum defect to be detected is scanned over the sub-field with an overlapping pattern to find defects such as excessive metal, metal in improper places or points where the metal is missing.

Abstract: A collar for fitting over the upper end of the cake discharge chute of a rotatable disc filter, or the like. The collar has a plurality of downwardly and inwardly sloping walls which substantially reduce any tendency for cake to stick to the sides of the chute. For use with heavy cake, reinforcing members may be provided for the collar. The collar is configured for use with discharge chutes of diverse design.

Abstract: A disc filter chute liner for being inserted in the passageway formed in a cake discharge chute of a disc filter and for being interposed between the cake discharge chute and cake passing therethrough and for preventing the cake from adhering to the cake discharge filter, the disc filter chute liner being provided with smooth and slick internal surfaces with respect to the cake whereby the cake passing through the liner will not adhere to the smooth and slick surfaces and thereby in turn will not adhere to the cake discharge chute.