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Military Standard MS28782-56 Teflon (PTFE) Retainer, Packing
PART #: SGP137214MFR PART #: MS28782-56Our Price: $14.34 (Each)QTY: Add to Cart -
Military Standard MS28782-57 Teflon (PTFE) Retainer, Packing
PART #: SGP137215MFR PART #: MS28782-57Our Price: $24.23 (Each)QTY: Add to Cart -
Military Standard MS28782-62 Teflon (PTFE) Retainer, Packing
PART #: SGP137219MFR PART #: MS28782-62Our Price: $14.89 (Each)QTY: Add to Cart -
Military Standard MS28782-64 Teflon (PTFE) Retainer, Packing
PART #: SGP137220MFR PART #: MS28782-64QTY: Add to Quote -
Military Standard MS9058-10 Teflon (PTFE) Retainer, Packing
PART #: SGP138586MFR PART #: MS9058-10Our Price: $3.05 (Each)QTY: Add to Cart -
Military Standard MS9058-07 Teflon (PTFE) Retainer, Packing
PART #: SGP138584MFR PART #: MS9058-07Our Price: $0.73 (Each)QTY: Add to Cart -
Military Standard MS9058-03 Teflon (PTFE) Retainer, Packing
PART #: SGP138580MFR PART #: MS9058-03Our Price: $1.43 (Pack)QTY: Add to Cart -
Military Standard MS9058-04 Teflon (PTFE) Retainer, Packing
PART #: SGP138581MFR PART #: MS9058-04Our Price: $1.91 (Pack)QTY: Add to Cart -
Military Standard MS9058-06 Teflon (PTFE) Retainer, Packing
PART #: SGP138583MFR PART #: MS9058-06Our Price: $1.27 (Pack)QTY: Add to Cart -
Military Standard MS9058-20 Teflon (PTFE) Retainer, Packing
PART #: SGP138589MFR PART #: MS9058-20Our Price: $17.63 (Pack)QTY: Add to Cart -
Military Standard MS9058-12 Teflon (PTFE) Retainer, Packing
PART #: SGP138587MFR PART #: MS9058-12Our Price: $2.82 (Pack)QTY: Add to Cart -
Military Specification M8791/1-226 Teflon (PTFE) Retainer, Packing
PART #: SGP130328MFR PART #: M8791-1-226Our Price: $1.75 (Each)QTY: Add to Cart
Ask any Skygeek and they will tell you a back-up ring functions on the principle of "everything needs support." As its name implies, it is a sturdy ring that "backs-up" (usually a rubber) seal. It is designed specifically to hold or maintain this seal in its proper position.
In many assemblies, joints require a seal. This is done so as to prevent the leakage of fluid or gas. O-rings are often used as a seal. However, due to extreme pressures inherent in aviation, these seals may extrude or lose their place and thus compromise their intended use. Back-up rings prevent extrusion and thus are used in conjunction with O-rings.
Back-up rings, like their O-ring counterparts, are usually made of elastic polymers, the most common being nitrile butadiene rubber (NBR) and polytetrafluoroethylene (PTFE or Teflon). Like other materials, elastomers are often given a hardness rating (durometer). This identifies a material's resistive strength, especially when dealing with pressures and other external forces. For instance, when viewing a back-up ring, you might find a 70 or 75A in its name; these numbers refer to its durometer.
Besides material, back-up rings can be classified by type, three variations include: spiral, endless, and endless split. A spiral back-up ring is the most frequently used because of its ability to efficiently self-adjust to diametrical tolerances. Endless back-up rings are applied whenever problems occur with the rotation of screwed endcaps that may cause a spiral type to unwind. The endless split back-up ring is identical to the endless back-up ring, the only difference is it is split at a 30-degree angle; this facilitates assembly for some applications.
Finally, back-up rings conform to several military specifications and Skygeek carries them including: MS27595, M8791, and MS9058. Our inventory is growing so check in from time to time. Otherwise, click on the specific series of back-up rings and make sure your seals are supported.