NBR90 Back-up rings

Category： Back-up rings
Temperature: -30 - +100℃
Material: NBR90
Color: black
Hardness: 90 shore A
Product description：Back-Up rings are routinely produced in a 90 durometer Nitrile - Buna-N. This provides sufficient elasticity to permit stretching over the major diameter of a piston and then snapping back into the gl
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1. Description

Back-Up rings are routinely produced in a 90 durometer Nitrile - Buna-N. This provides sufficient elasticity to permit stretching over the major diameter of a piston and then snapping back into the gland groove cut into the piston. 90 durometer has sufficient hardness to resist extrusion of the softer elastomeric O-Ring performing the actual sealing function against the high pressure liquid or gas.

2. Sectional Drawing

3. Back-Up Ring Design Reference

Size		Tolerance in mm
From	To	W.	TOL.±	T.(REF.)	TOL.±	A.	TOL.±	R
-4	-50	1.35	0.08	1.2	0.08	1.14	0.08	2.21
-102	-178	2.18	0.08	1.28	0.08	1.14	0.08	3.28
-201	-284	3	0.1	1.23	0.08	1.02	0.08	4.42
-309	-395	4.65	0.13	1.88	0.1	1.52	0.1	6.65
-425	-475	5.99	0.15	2.97	0.13	2.44	0.13	8.74