Technical

In general, the ring is located in an annular groove on the piston. It rests on the cylinder. It insures a seal between an area under pressure and a volume without any pressure. There could be a requirement to scrape the oil of the cylinder. The seal is assured with the combination of:

• The clamping effect between the flat face of the ring and one of the faces in the groove of the piston.
• The contact between the outside diameter of the ring and the cylinder where used.

The ring applies a specific pressure on the surface. The pressure (P) varies with the modulus of elasticity of the metal (E), free opening (m) and the square root of the radial thickness. The tangential force (Ft) allows to measure the pressure and should be chosen depending on the use of the ring. It is the responsibility of the manufacturer to define the dimensions al and m including the value for Ft. The DIN, BSI and ISO norms recommend certain dimension depending on applications.

Coefficient of expansion:

For each increase of 100°C in temperature, grey iron expands by 1.01mm per meter.