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Military Standard MS28782-35 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-35 Teflon (PTFE) Retainer, Packing
PART #: SGP137196MFR PART #: MS28782-35Our Price: $0.98 (Each)QTY: Add to Cart -
Military Standard MS28782-37 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-37 Teflon (PTFE) Retainer, Packing
PART #: SGP137198MFR PART #: MS28782-37Our Price: $5.69 (Each)QTY: Add to Cart -
Military Standard MS28782-38 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-38 Teflon (PTFE) Retainer, Packing
PART #: SGP137199MFR PART #: MS28782-38Our Price: $7.39 (Each)QTY: Add to Cart -
Military Standard MS28782-47 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-47 Teflon (PTFE) Retainer, Packing
PART #: SGP137208MFR PART #: MS28782-47Our Price: $6.16 (Each)QTY: Add to Cart -
Military Standard MS28782-55 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-55 Teflon (PTFE) Retainer, Packing
PART #: SGP137213MFR PART #: MS28782-55Our Price: $12.86 (Each)QTY: Add to Cart -
Military Standard MS27595-221 Retainer, Packing
Military Standard MS27595-221 Retainer, Packing
PART #: SGP136540MFR PART #: MS27595-221Our Price: $1.33 (Each)QTY: Add to Cart -
Military Standard MS28774-226 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-226 Teflon (PTFE) Retainer, Packing
PART #: SGP136744MFR PART #: MS28774-226Our Price: $1.39 (Each)QTY: Add to Cart -
Military Standard MS28782-1 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-1 Teflon (PTFE) Retainer, Packing
PART #: SGP137168MFR PART #: MS28782-1Our Price: $2.04 (Each)QTY: Add to Cart -
Military Standard MS28782-30 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-30 Teflon (PTFE) Retainer, Packing
PART #: SGP137191MFR PART #: MS28782-30Our Price: $3.82 (Each)QTY: Add to Cart -
National Aerospace Standard NAS1523-5R Packing with Retainer
National Aerospace Standard NAS1523-5R Packing with Retainer
PART #: SGP140653MFR PART #: NAS1523-5ROur Price: $7.86 (Each)QTY: Add to Cart -
Military Standard MS28774-131 Teflon (PTFE) Retainer, Packing
Military Standard MS28774-131 Teflon (PTFE) Retainer, Packing
PART #: SGP136709MFR PART #: MS28774-131Our Price: $1.15 (Each)QTY: Add to Cart -
Military Standard MS28777-5 Leather Retainer, Packing
Military Standard MS28777-5 Leather Retainer, Packing
PART #: SGP137145MFR PART #: MS28777-5Our Price: $2.07 (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.