Pinhole Detector Type (Developed by Kyokuto Rubber) / Rubber Expansion Joint

Continuous usage of rubber expansion joints may cause small gashes (pinholes) in the inner and outer surface rubber of the expansion joint. The pinhole detector type is a rubber expansion joint designed for easier detection of pinholes in the inner and outer surface rubber. It is designed and manufactured for pinhole detection using pinhole testers used for paint inspection. By using a special rubber that has electricity flowing inside of the expansion joint and by scanning the surface of the rubber with metal brushes of the pinhole tester, it becomes possible to detect the presence of pinholes.


  • Since pinholes in the inner and outer surface rubber of expansion joints can be detected, it is an aspect to determine abnormalities in the rubber.
  • Combined usage with conductive sealing enables monitoring of the inner rubber during operation.
  • There is no risk of electrical conductivity as rubber with excellent insulation is used.
  • As the standard type is the structural basis, it possesses all of the standard type features. It is also possible to make an eccentric type adjusted accordingly to misalignment (eccentricity) of piping.


Kyokuto Rubber Co., Ltd.
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