-
Military Standard MS27595-026 Retainer, Packing
PART #: SGP136494MFR PART #: MS27595-026Our Price: $1.37 (Each)QTY: Add to Cart -
Military Standard MS27595-025 Retainer, Packing
PART #: SGP136493MFR PART #: MS27595-025Our Price: $2.15 (Each)QTY: Add to Cart -
Military Standard MS27595-119 Retainer, Packing
PART #: SGP136503MFR PART #: MS27595-119Our Price: $1.32 (Each)QTY: Add to Cart -
Military Standard MS27595-124 Retainer, Packing
PART #: SGP136507MFR PART #: MS27595-124Our Price: $1.50 (Each)QTY: Add to Cart -
Military Standard MS27595-127 Retainer, Packing
PART #: SGP136510MFR PART #: MS27595-127Our Price: $1.87 (Each)QTY: Add to Cart -
Military Standard MS27595-126 Retainer, Packing
PART #: SGP136509MFR PART #: MS27595-126Our Price: $1.61 (Each)QTY: Add to Cart -
Military Standard MS27595-130 Retainer, Packing
PART #: SGP136513MFR PART #: MS27595-130Our Price: $1.91 (Pack)QTY: Add to Cart -
Military Standard MS27595-131 Retainer, Packing
PART #: SGP136514MFR PART #: MS27595-131Our Price: $1.86 (Each)QTY: Add to Cart -
Military Standard MS27595-133 Retainer, Packing
PART #: SGP136516MFR PART #: MS27595-133Our Price: $1.83 (Pack)QTY: Add to Cart -
Military Standard MS27595-132 Retainer, Packing
PART #: SGP136515MFR PART #: MS27595-132Our Price: $1.89 (Each)QTY: Add to Cart -
Military Standard MS27595-136 Retainer, Packing
PART #: SGP136518MFR PART #: MS27595-136Our Price: $1.43 (Pack)QTY: Add to Cart -
Military Standard MS27595-135 Retainer, Packing
PART #: SGP136517MFR PART #: MS27595-135Our Price: $1.78 (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.