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National Aerospace Standard NAS1523AA4N Packing with Retainer
National Aerospace Standard NAS1523AA4N Packing with Retainer
PART #: SGP140695MFR PART #: NAS1523AA4NOur Price: $3.25 (Each)QTY: Add to Cart -
Military Standard MS28774-138 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-138 Teflon (PTFE) Retainer, Packing
PART #: SGP136716MFR PART #: MS28774-138Our Price: $1.21 (Each)QTY: Add to Cart -
National Aerospace Standard NAS1523C08R Packing with Retainer
National Aerospace Standard NAS1523C08R Packing with Retainer
PART #: SGP140720MFR PART #: NAS1523C08ROur Price: $4.39 (Each)QTY: Add to Cart -
Military Standard MS28774-133 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-133 Teflon (PTFE) Retainer, Packing
PART #: SGP136711MFR PART #: MS28774-133Our Price: $1.30 (Each)QTY: Add to Cart -
Military Standard MS28774-008 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-008 Teflon (PTFE) Retainer, Packing
PART #: SGP136666MFR PART #: MS28774-008Our Price: $0.70 (Each)QTY: Add to Cart -
Military Standard MS28774-236 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-236 Teflon (PTFE) Retainer, Packing
PART #: SGP136754MFR PART #: MS28774-236Our Price: $2.37 (Each)QTY: Add to Cart -
Military Standard MS28774-332 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-332 Teflon (PTFE) Retainer, Packing
PART #: SGP136772MFR PART #: MS28774-332Our Price: $2.62 (Each)QTY: Add to Cart -
National Aerospace Standard NAS1523AA9B Packing with Retainer
National Aerospace Standard NAS1523AA9B Packing with Retainer
PART #: SGP140710MFR PART #: NAS1523AA9BOur Price: $5.46 (Each)QTY: Add to Cart -
Military Standard MS28774-235 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-235 Teflon (PTFE) Retainer, Packing
PART #: SGP136753MFR PART #: MS28774-235Our Price: $3.23 (Each)QTY: Add to Cart -
Military Standard MS28774-326 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-326 Teflon (PTFE) Retainer, Packing
PART #: SGP136766MFR PART #: MS28774-326Our Price: $1.07 (Each)QTY: Add to Cart -
National Aerospace Standard NAS1523C4E Packing with Retainer
National Aerospace Standard NAS1523C4E Packing with Retainer
PART #: SGP140733MFR PART #: NAS1523C4EOur Price: $1.45 (Each)QTY: Add to Cart -
Military Standard MS28774-328 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-328 Teflon (PTFE) Retainer, Packing
PART #: SGP136768MFR PART #: MS28774-328Our Price: $1.25 (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.