Flange (static face Seals)

An outer extrusion resistant lamina bonded to an inner pressure responsible sealing lamina


Series 11 Flange Seals are designed for use on all Hydraulic Flanged Tube, Pipe and Hose Connections, 4 Bolt Split Flange Type, as detailed in SAE Standard 1518c. They provide a direct replacement for the O-rings without any modifications of the existing grooves.

Special sizes of Flange Seals may be economically produced for a variety of other applications, including manifold mounted pumps, stack valves and similar static hydraulic applications.

Flange Seals are a one piece, dual durometer static seal that consists of an outer lamina of Unithane 395A polyurethane. This material provides maximum extrusion resistance for the inner sealing lamina of Unithane 157A polyurethane which exhibits extremely low compression set and has excellent sealing characteristics. Refer to Technical Bulletin US 96 for specific details on all Unithane materials.

Flange Seals are suitable for use in standard hydraulic fluids in a temperature range of -40 degrees F to +195 degrees F and 0 to 3000 P.S.I.

This unique combination of an outer extrusion resistant lamina bonded to an inner pressure responsive sealing lamina provides improved sealing performance and longer service life than normally can be obtained by O-rings or other more expensive devices.


  • Outer Lamina: Unithane 395A liquid cast Polyurethane, Duro 95A.
  • Inner Lamina: Unithane 157A liquid cast Polyurethane, Duro 57A.
  • Fluid Compatibility: See Material Specification: Technical Bulletin US- 96