GROOVE DESIGN CRITERIA 

Due to the many diverse applications in which ENCAP-O-SEAL^TM Teflon® encapsulated O-ring is utilized, the effects of thermal expansion, extrusion and compression set are important considerations in groove design. To determine recommended gland dimensions and AS568A dash numbers, the designer should first select the intended sealing application from the following list (1-5) and refer to the Groove Assistant^TM for dimensions. It should be noted that these standard dimensions are the same as for all elastomer O-rings and can be used as a starting point when evaluating an effective seal. *See Groove Assistant^TM for gland dimensions.  Click here for image

1.) Static Face Seal - Rectangular Gland - Internal vacuum - External pressure.  Click here for image

2.) Static Face Seal - Rectangular Gland - Internal pressure - External vacuum.  Click here for image

3.) Static Face Seal - Dovetail Gland - Any pressure combination.  Click here for image

4.) Static I.D./O.D. Seal - Rectangular Gland - Any pressure combination.  Click here for image

5.) Dynamic I.D./O.D. Seal - Rectangular Gland - Any pressure combination.  Click here for image

SEAL EXTRUSION RADIAL CLEARANCE GAPS 

If the radial clearance gap between the sealing surface and the groove corners are to large and the pressure exceeds the deformation limit of the O-ring, extrusion of the ring material will occur. When this happens, the extruded material wears or frays with cycling. Corrective measures are:

1) Preferred…close the clearance gap by modifying the metal dimensions, or use backup washers or other anti-extrusion devices, or

2) Use a harder, higher modulus compound at the expense of higher friction and greater tendency to leak at lower pressure ranges.  Click here for image