Backup Ring | Aerospace Digital Catalogue

CDI is trusted by the world’s major aircraft manufacturers for everything from flight control actuators to landing gear. Our industry-leading sealing systems are made from time-tested materials and are specifically built to meet any application need.
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Materials

Backup Rings

The backup ring is a rectangular cross section ring, installed in the seal gland next to the seal (typically an O-ring) whose main function of the backup ring is to prevent the O-ring from extruding. O-rings will extrude under adverse conditions of pressure, temperature, fluid compatibility, and diametral extrusion clearance. This is achieved by using a backup ring made from PTFE (polytetrafluoroethylene) or other similar polymer material which deforms under pressure to maintain essentially zero extrusion clearance and provides improved support for the O-ring. Backup rings are effective for under both static and dynamic conditions. Backup rings made from PTFE are also effective in hostile environments, which may reduce the ability of the O-ring to resist extrusion because of temporary or permanent changes in the physical properties of the elastomer.

Features and Benefits

  • Provides extrusion protection for O-Rings
  • Increases the service life of O-Rings
  • Permits O-Rings to be utilized in higher pressure applications.
  • Nearly unlimited media and gas compatibility
  • Easy Installation
  • Wide range of geometries to meet the needs of all applications.
  • Industry Part Standards
    • MS28774 - RETAINER, PACKING BACKUP, SINGLE TURN, POLYTETRAFLUOROETHYLENE
    • MS28782 - RETAINER, PACKING, BACK-UP, TEFLON
    • MS27595 - RETAINER, PACKING BACKUP, CONTINUOUS RING, POLYTETRAFLUOROETHYLENE
    • MS28773 - RETAINER, PACKING, BACK-UP, TETRAFLUOROETHYLENE, STRAIGHT THREAD TUBE FITTING BOSS
    • MS9058 - RING-BACK-UP, BOSS CONNECTION,
    • AS5781 - Retainers (Backup Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Single Turn, Scarf-Cut, For Use in AS4716 Glands
    • AS5782 - Retainers (Backup Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Solid, Un-Cut, for Use in AS4716 Glands
    • AS5860 - Retainers (Backup Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Single Turn, Scarf-Cut, For Use in AS5857 Static Glands
    • AS5861 - Retainers, (Backup Rings), Hydraulic and Pneumatic, Polytetrafluoroethylene Resin, Solid, Un-Cut, for Use in Static Glands to AS5857
    • AS8791 (M8791/1) - Hydraulic and Pneumatic Retainers (Backup Rings), Polytetrafluoroethylene (PTFE) Non-standard sizes also available
  • Continuous uncut backup rings, single turn cut (scarf cut) backup ring, spiral-cut backup ring, and special designed backup rings available for MIL-G-5514, AS4716, AS5202, AS5179 and AS5857
  • For further information on backup rings, please reference SAE-AIR1802 “Selection and Application of Polytetrafluoroethylene (PTFE and TFE) Backup Rings for Hydraulic and Pneumatic Fluid Power Applications
BACKUP RING (1)

Product Specs.

Download Tech Specs PDF
Dash Size Ø I.D. Min Ø I.D. Max Ø O.D. Min Ø O.D. Max T Min T Max W Min W Max G Min G Max A° Min A° Max Share
004 0.075 0.077 N/A N/A 0.048 0.052 0.056 0.058 0.000 0.005 35 39 Link Part #
005 0.107 0.109 N/A N/A 0.048 0.052 0.053 0.055 0.000 0.005 32 36 Link Part #
006 0.122 0.124 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 29 33 Link Part #
007 0.153 0.155 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 24 27 Link Part #
008 0.184 0.186 N/A N/A 0.048 0.052 0.053 0.055 0.000 0.005 19 22 Link Part #
009 0.216 0.218 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
010 0.247 0.249 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
011 0.309 0.311 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
012 0.372 0.374 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
013 0.434 0.436 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
014 0.497 0.499 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
015 0.559 0.561 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
016 0.622 0.624 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
017 0.684 0.686 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
018 0.747 0.749 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
019 0.809 0.811 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
020 0.872 0.874 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
021 0.934 0.936 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
022 0.997 0.999 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
023 1.059 1.061 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
024 1.122 1.124 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
025 1.184 1.186 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
026 1.247 1.249 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
027 1.310 1.312 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
028 1.373 1.375 N/A N/A 0.048 0.052 0.054 0.056 0.000 0.005 19 22 Link Part #
104 0.122 0.124 N/A N/A 0.056 0.060 0.084 0.086 0.000 0.006 19 22 Link Part #
105 0.153 0.155 N/A N/A 0.056 0.060 0.084 0.086 0.000 0.006 19 22 Link Part #
106 0.184 0.186 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
107 0.216 0.218 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
108 0.247 0.249 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
109 0.309 0.311 N/A N/A 0.056 0.060 0.086 0.088 0.000 0.006 19 22 Link Part #
110 0.372 0.374 N/A N/A 0.056 0.060 0.084 0.086 0.000 0.006 19 22 Link Part #
111 0.434 0.436 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
112 0.497 0.499 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
113 0.559 0.561 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
114 0.622 0.624 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
115 0.684 0.686 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
116 0.747 0.749 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
117 0.809 0.811 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
118 0.872 0.874 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
119 0.934 0.936 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
120 0.997 0.999 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
121 1.059 1.061 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
122 1.122 1.124 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
123 1.184 1.186 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
124 1.247 1.249 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
125 1.310 1.312 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
126 1.373 1.375 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
127 1.436 1.438 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
128 1.500 1.502 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
129 1.562 1.564 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
130 1.626 1.628 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
131 1.688 1.690 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
132 1.752 1.754 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
133 1.815 1.817 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
134 1.878 1.880 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
135 1.942 1.944 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
136 2.004 2.006 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
137 2.068 2.070 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
138 2.122 2.124 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
139 2.185 2.187 N/A N/A 0.056 0.060 0.085 0.087 0.000 0.006 19 22 Link Part #
210 0.747 0.749 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
211 0.809 0.811 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
212 0.872 0.874 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
213 0.934 0.936 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
214 0.997 0.999 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
215 1.059 1.061 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
216 1.122 1.124 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
217 1.184 1.186 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
218 1.247 1.249 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
219 1.309 1.311 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
220 1.372 1.374 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
221 1.434 1.436 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
222 1.498 1.500 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
223 1.622 1.624 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
224 1.747 1.749 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
225 1.872 1.874 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
226 1.997 1.999 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
227 2.122 2.124 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
228 2.247 2.249 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
229 2.372 2.374 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
230 2.497 2.499 N/A N/A 0.060 0.064 0.119 0.121 0.000 0.006 19 22 Link Part #
325 1.497 1.499 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 19 22 Link Part #
326 1.622 1.624 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 19 22 Link Part #
327 1.747 1.749 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 19 22 Link Part #
328 1.872 1.874 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 19 22 Link Part #
329 1.997 1.999 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 19 22 Link Part #
330 2.122 2.124 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 19 22 Link Part #
331 2.247 2.249 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 19 22 Link Part #
332 2.372 2.374 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 19 22 Link Part #
333 2.497 2.499 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 19 22 Link Part #
334 2.622 2.624 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
335 2.747 2.749 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
336 2.872 2.874 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
337 2.996 2.998 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
338 3.121 3.123 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
339 3.246 3.248 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
340 3.371 3.373 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
341 3.496 3.498 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
342 3.621 3.623 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
343 3.746 3.748 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
344 3.871 3.873 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
345 3.996 3.998 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
346 4.121 4.123 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
347 4.246 4.248 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
348 4.371 4.373 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
349 4.496 4.498 N/A N/A 0.086 0.090 0.184 0.186 0.000 0.007 12 15 Link Part #
425 4.496 4.498 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
426 4.621 4.623 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
427 4.746 4.748 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
428 4.871 4.873 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
429 4.996 4.998 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
430 5.121 5.123 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
431 5.246 5.248 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
432 5.371 5.373 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
433 5.496 5.498 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
434 5.621 5.623 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
435 5.746 5.748 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
436 5.871 5.873 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #
437 5.996 5.998 N/A N/A 0.127 0.131 0.236 0.238 0.000 0.008 12 15 Link Part #