BACK-UP RING PISTON SEAL

Back-up Rings are pure hard rubber piece with concave on one side relative to the o-ring shape, having no intended sealing function. Instead, as their name indicates, they are protective and supporting elements made from extrusion-resistant materials. They are installed in a groove together with an elastomeric sealing element preferably with a corresponding O-Ring, in both dynamic and static applications, to prevent extrusion of the O-ring when it is subject to high pressures or elevated temperatures. Elevated temperatures (160° F and higher) impose a severe burden on the physical and mechanical properties of rubber O Rings which further increases their tendency to extrude. Two back-up rings should be used with one on each side of the primary seal. Due to the tight fit of the Back-up Ring in the housing, they prevent extrusion of the pressurised elastomeric sealing element into the sealing gap.

Height ID Part No Width
1.5 61 BU 11006100 049 4.9
1.5 64 BU 11006400 049 4.9
1.5 67 BU 11006700 049 4.9
1.5 70 BU 11007000 049 4.9
1.5 74 BU 11007400 019 4.9
1.5 77 BU 11007700 049 4.9
1.5 80 BU 11008000 049 4.9
1.5 83 BU 11008300 049 4.9
1.5 86 BU 11008600 049 4.9
1.7 90 BU 11009000 049 4.9