Patent ID: 9709457
Date: 2017-07-18
CPC Classifications: B01D,G01M

Claim:
1. A method of detecting defects generated in a honeycomb structural body comprised of a plurality of cell walls arranged in a lattice shape and with a skin layer, the cell walls being arranged to form a plurality of cells, each of the cells having a polygonal shape in a cross section of the honeycomb structural body perpendicular to a gas supply direction, and an outer peripheral surface of the honeycomb structural body being covered with the skin layer, the method comprising steps of: sealing both end sections of the honeycomb structural body; supplying gas from one end section to the other end section of the honeycomb structural body; detecting sounds of gas leaking from the skin layer of the honeycomb structural body by using one or more microphones arranged at an outer periphery of the skin layer; and judging a presence of defects such as holes having a predetermined diameter and cracks generated in the skin layer on the basis of a detected magnitude of sounds of the leaking gas; wherein in the sealing step, balloons hold and support the outer periphery near to the end sections of the honeycomb structural body in order to seal both the end sections of the honeycomb structural body by using the balloons.