How To Solve The O-rings Fracture

- Sep 13, 2017-

How to solve the O-rings fracture
 How do you know the O-rings breaks? Do you know how to deal with this situation?
Visual inspection
A critical step in this failure analysis is a thorough examination of the mechanical damage to the O-rings. Obviously, all three O-rings have been damaged, which will lead to leakage. Surprisingly, all three O-rings are broken in the direction of the pressure source, rather than deviating from it. However, ignoring other causes that may lead to failure may lead to the neglect of more critical factors that can lead to the best precautionary approach. In this example, the O-rings does not produce any other mechanical damage. For example, this O-rings does not have evidence of pressure-related extrusion failure, when the fluid pressure exceeds the strength of the material, the rubber will be squeezed into the gap between the accessories, leaving "damage" Rubber area. This situation is clearly not present on this O-rings. And there is no indication that this O-rings has produced any way of compression between the assembled parts.
In addition, the rubber material does not have any signs of chemical decomposition or thermal degradation. Unlike other damage points, the O-rings is not significantly expanded, hardened, softened, blistering, compression deformation, embrittlement or loss of tensile strength. Very simple, no damage compared to other obvious damage. For these reasons, the chemical and thermal incompatibility factors of these sealing materials have proven to be not a potential factor in the underlying cause of failure.
Analysis of the fracture
O-rings failure is most often seen in order to meet the application, O-rings is stretched in the assembly process. In this case, though, the O-rings passed the initial leak test and was used for several weeks. For the damaged O-rings it is impossible. Therefore, the O-rings must be no damage during installation and initial pressure testing. This means that the O-rings is certainly damaged during use, that is, when it is installed in the tank, this is a very rare case in a static O-rings seal. Damage to this type of use can usually be traced back to one or two reasons.
The most common cause of O-rings damage in use is tearing, which is spread from the initial twist point. In this case, a portion of the O-rings is crushed in the fitted mating metal part, usually when the groove is accidentally ejected during the installation. O-rings damaged in this way will show signs of significant mechanical damage, including: part of the serious crushing, O-rings part of the missing, cross-section was semi-circular resection and so on. In some cases, a tightened O-rings passes through the initial leak test and is damaged during use, due to the initial shrinkage of the O-rings. However, there is no evidence of any shrinkage damage in these failed O-rings.
 O-rings manufacturers for the use of lubricants is also very large, mainly because O-rings into the use of the use, must be used in conjunction with the lubricants to make the O-rings normal role, it can be said that the two Is inseparable.
O-rings seal effect formation: dynamic seal is divided into non-contact seal and contact seal. Non-contact seal is mainly a variety of mechanical seals, such as: graphite packing ring, floating ring seal, etc .; rubber composite O-rings and rubber and plastic combination O-rings are contact seals, by filling in the sealed cavity pre-compression Force, blocking the leakage channel and get the sealing effect. Hydraulic system with O-rings for static seal (end seal), reciprocating seal (piston, piston rod seal) and rotary seal.
O-rings is a type of O-rings shape, its shape into O-type, which is because the whole market demand for it, but not to say that this O-rings is certainly particularly good, in fact, O-rings Compared with other O-rings, there will be some of its own shortcomings.
Compared with other O-rings, there are three drawbacks:
1, starting the frictional resistance.
2, used as a pneumatic device seal, you must add lubricating oil to prevent wear.
3, the coupling parts, such as the moving surface, grooves, gaps and other processing size and accuracy requirements are very strict.
When using the O-rings, its size is fixed, it is not common, otherwise it will cause the seal is not tight.

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