Piston ring with radio-active tracer - indicates if non-cylindrical piston rings are correctly installed

摘要

The piston ring is of non-cylindrical form in that the outer surface is slightly coned and for correct installation a given surface must be uppermost. To ensure this the butting face is made radioactive by exposing it to radiation from a radioactive isotope. It is then possible with the use of a Geiger counter to detect if the piston ring is correctly installed by the means described in the main patent. An alternative method of checking for correct installation is by magnetising the ring and then detecting the direction of the magnetic field in the ring after installation. The method of marking is permanent and does not disappear as a result of ring wear.