-
Military Standard MS27595-023 Retainer, Packing
PART #: SGP136492MFR PART #: MS27595-023Our Price: $0.93 (Pack)QTY: Add to Cart -
Military Standard MS27595-115 Retainer, Packing
PART #: SGP136500MFR PART #: MS27595-115Our Price: $1.58 (Each)QTY: Add to Cart -
Military Standard MS27595-118 Retainer, Packing
PART #: SGP136502MFR PART #: MS27595-118Our Price: $1.75 (Each)QTY: Add to Cart -
Military Standard MS27595-120 Retainer, Packing
PART #: SGP136504MFR PART #: MS27595-120Our Price: $1.56 (Each)QTY: Add to Cart -
Military Standard MS27595-121 Retainer, Packing
PART #: SGP136505MFR PART #: MS27595-121Our Price: $1.54 (Each)QTY: Add to Cart -
Military Standard MS27595-123 Retainer, Packing
PART #: SGP136506MFR PART #: MS27595-123Our Price: $1.28 (Pack)QTY: Add to Cart -
Military Standard MS27595-125 Retainer, Packing
PART #: SGP136508MFR PART #: MS27595-125Our Price: $1.73 (Each)QTY: Add to Cart -
Military Standard MS27595-128 Retainer, Packing
PART #: SGP136511MFR PART #: MS27595-128Our Price: $1.80 (Pack)QTY: Add to Cart -
Military Standard MS27595-143 Retainer, Packing
PART #: SGP136525MFR PART #: MS27595-143Our Price: $2.63 (Pack)QTY: Add to Cart -
Military Standard MS27595-144 Retainer, Packing
PART #: SGP136526MFR PART #: MS27595-144Our Price: $2.56 (Each)QTY: Add to Cart -
Military Standard MS27595-145 Retainer, Packing
PART #: SGP136527MFR PART #: MS27595-145Our Price: $2.86 (Pack)QTY: Add to Cart -
Military Standard MS27595-148 Retainer, Packing
PART #: SGP136528MFR PART #: MS27595-148Our Price: $3.00 (Pack)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.