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Failure reason and Countermeasure of O ring
Time : 2019-07-26 Hits : 248
(1) Installation damage
Invalid condition: the part or all of the seal is in good order.
Failure
reason: the edge of the groove and other parts is sharp, the size of
the sealing parts is not suitable; the hardness or elasticity of the
seal is too low; the surface of the seal is polluted.
Solution:
clear sharp corners; groove design is more reasonable; choose the right
size of the seal; choose greater flexibility, higher hardness seals.
(2) Curl
Failure state: O ring appears obvious curl
Failure
reason: the installation causes, the movement speed is too low, the
material is too hard or the elasticity is too small, the O ring surface
treatment is uneven, the groove size is uneven, the groove surface is
rough, the lubrication is insufficient.
Solution:
proper installation, use of high elastic material, appropriate to
improve the design and surface smoothness of the groove, as far as
possible to use the support ring.
(3) Over compression
Failure state: O ring, the contact surface is flat deformation, and may be accompanied by cracks.
Failure
reason: the design is unreasonable, without considering the material
due to heat and chemical medium caused by deformation, or too much
pressure caused by deformation.
Solution:
the design of the trench shall take into account the deformation of the
material due to temperature and chemical medium.
(4) Permanent compression deformation
Failure state: the contact surface of the seal presents a flat permanent deformation.
Failure
reason: too much pressure; too high temperature; the material has not
completed curing; the material itself has a permanent deformation rate;
the material is too expansive in the chemical medium.
Solution: choose low deformation material; proper groove design; confirm material compatibility with medium.
(5) Chemical corrosion damage
Failure
state: chemical corrosion can cause various defects in the O ring, such
as foaming, cracking, small holes, or fading. At some point, chemical
corrosion can only be obtained by measuring its physical properties by
means of an instrument.
Failure cause: material not in accordance with medium or excessive temperature.
Solution: choose more resistant chemical medium corrosion of the material.
(6) Damage
Failure
state: O type ring, all or part of the sealing area, wear and tear, can
be found in the sealing surface of materials wear particles.
Failure
reasons: sealing surface finish is not enough, the temperature is too
high, the sealing environment into the wear debris, sealing parts
produce relative movement, sealing surface treatment is not complete.
Solution: improve groove finish, choose self lubrication material, and clearly cause worn parts and environment.
(7) Blasting
The
state of failure: O ring appears on the surface of bubbles, pits,
scars; a lot of pressure when the material absorption gas, when the
pressure suddenly decreases, the gas absorption materials caused by the O
ring run fast, surface blasting.
Failure reason: pressure changes too fast, material hardness and elasticity are too low.
Solution: choose higher hardness, better elasticity of material, reduce the speed of decompression.
(8) Debris pollution
Failure state: O ring section of foreign body.
Failure
reason: the production process is polluted by the environment, and the
material is corroded or reacted. The material is non - semiconductor
grade material.
Solution:
indicate cleanliness of production and packaging requirements, and
strengthen environmental control during production and transportation of
O rings.
(9) Hot corrosion
Failure
state: the high temperature contact surfaces of O rings exhibit radial
cracks, and some may soften or become more lustrous due to excessive
temperature.
Failure
reason: the material can not withstand high temperature or temperature
beyond the design temperature, or the temperature changes too
frequently.
Solution: choose materials with high temperature resistance, such as possible to reduce the sealing surface temperature.
