General
Performances and types
Selection criterions for metal O-rings
Coating and quality of finish
Sealing specification

	Standard type This type is not self-energizing or pressure-filled, produced of different metallic tubings or solid wire and the most reasonable O-ring type for low to moderate pressure or vacuum ratios.
	Self-energizing type At the inside or outside diameter the O-ring shows borings and grooves, thereby the same pressure originates in the inside as in the system. They system pressure supports the sealing behavior.
	Pressure-filled type Pressure-filled O-rings have been designed especially for temperatures from 425 degrees centigrade up to 980 degrees centigrade above zero. They are less pressure resistant the self-energizing type, contain a gas filling of approx. 40 bar pressure or more, the gas pressure increases upon higher temperatures and compensates the initial tension deficiency of the flanged joint and increases the sealing force thereby.

Typical applications

GFD metal O-rings are successfully used in vacuum or high-pressure systems as well in critical ranges for hydraulic units and lubricating oils, jet engines and rocket propellants, liquid metals and combustion gases. They yield positive and leakproof seals in tube systems and with production processes for the chemical, petrochemical, petroleum, natural gas and refinery industry. Many manufacturers of reciprocating engines, heat exchangers, gas turbines, pressure vessels, injection units, high-pressure filters and other elements rely on metal O-rings as a permanent and highly stressable seal. Some common applications are illustrated below:

quick release coupling	screwed flange	heat exchanger/pressure vessel
screwed cover	screwing with external pressure	nuclear power station pressure vessel