In order to be able to select the appropriate metal O-ring for a particular application the pressure, the temperature and the kind of the media to be sealed in the system have to be known:
The tube profile section is determined by means of the outside diameter of the rings, the desired force of pressure and the available space. The wall thickness thus has to be selected that an adequate force of pressure accrues upon the appropriate deformation. The following data comprehend the common wall thicknesses, which can be applied for each diameter. With electroplated surfaces, seals with a tube wall thickness &Mac179; 3.2 mm diameter and load of approx. 72 N/mm peripheral length lead to a plastic deformation of the electroplating. For tubing with a diameter &Mac178; 3.2 mm a pressing of 140 N/mm peripheral length is required. Teflon*) coatings on rings are plastically deformed with a load of 18 N/mm peripheral length.
The correct dimension and quality of finish of the groove are as important as the O-ring itself for the use of the seal. The following recommended groove dimensions for internal and external pressure applications are to be understood as general recommendations for the preparation of sealing faces. The dimensions in the list refer to rings, which are not electroplated. Groove depths for rings with a profile section of 0.9 mm are increased by the double of the coating thickness. Groove depths for electroplated or coated rings with a tube diameter of 1.6 mm or more are not increased.
Recommended groove dimensions: B (= max. outside O-Ring dia.) as well as A (= min. inside O-ring dia.) are values including coating