Patent ID: 7701570

Claim:
A system for detecting defective cells in a ceramic honeycomb body having an outer periphery and first and second opposite end faces each with open and plugged cells formed respectively by first and second sets of plugs, the system comprising: a housing having an end provided with a transparent window that serves as a mounting surface upon which the first end face rests and contacts, and that is not part of or fixed to the honeycomb body, and a light block arranged adjacent the transparent window and sized to the honeycomb body outer periphery, the housing further having an inside that contains a light source which launches substantially collimated light through the transparent window and into the first end face of the honeycomb body and a projection medium disposed adjacent and in contact with the second end face of the honeycomb body, wherein the projection medium receives light emerging from the second end face through at least one defect in at least one of the first and second sets of plugs, and wherein the projection medium comprises a translucent material or a woven screen upon which said received light appears visible to an observer and is representative of the at least one defect.