-
Military Standard MS28782-21 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-21 Teflon (PTFE) Retainer, Packing
PART #: SGP137181MFR PART #: MS28782-21Our Price: $1.86 (Each)QTY: Add to Cart -
Military Standard MS28782-22 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-22 Teflon (PTFE) Retainer, Packing
PART #: SGP137182MFR PART #: MS28782-22Our Price: $2.43 (Each)QTY: Add to Cart -
Military Standard MS28782-23 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-23 Teflon (PTFE) Retainer, Packing
PART #: SGP137183MFR PART #: MS28782-23Our Price: $3.05 (Each)QTY: Add to Cart -
Military Standard MS28782-24 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-24 Teflon (PTFE) Retainer, Packing
PART #: SGP137184MFR PART #: MS28782-24Our Price: $2.95 (Each)QTY: Add to Cart -
Military Standard MS28782-25 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-25 Teflon (PTFE) Retainer, Packing
PART #: SGP137185MFR PART #: MS28782-25Our Price: $1.44 (Each)QTY: Add to Cart -
Military Standard MS28782-28 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-28 Teflon (PTFE) Retainer, Packing
PART #: SGP137188MFR PART #: MS28782-28Our Price: $3.50 (Each)QTY: Add to Cart -
Military Standard MS28782-29 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-29 Teflon (PTFE) Retainer, Packing
PART #: SGP137189MFR PART #: MS28782-29Our Price: $0.65 (Each)QTY: Add to Cart -
Military Standard MS28782-33 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-33 Teflon (PTFE) Retainer, Packing
PART #: SGP137194MFR PART #: MS28782-33Our Price: $4.89 (Each)QTY: Add to Cart -
Military Standard MS28782-39 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-39 Teflon (PTFE) Retainer, Packing
PART #: SGP137200MFR PART #: MS28782-39Our Price: $5.76 (Each)QTY: Add to Cart -
Military Standard MS28782-41 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-41 Teflon (PTFE) Retainer, Packing
PART #: SGP137203MFR PART #: MS28782-41Our Price: $7.55 (Each)QTY: Add to Cart -
Military Standard MS28782-50 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-50 Teflon (PTFE) Retainer, Packing
PART #: SGP137211MFR PART #: MS28782-50Our Price: $7.34 (Each)QTY: Add to Cart -
Military Standard MS28782-6 Teflon (PTFE) Retainer, Packing
Military Standard MS28782-6 Teflon (PTFE) Retainer, Packing
PART #: SGP137218MFR PART #: MS28782-6Our Price: $1.50 (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.