1. O-ring is hardened and oxidized by heat
① Because the working temperature exceeds the normal use range, the elastomer hardens, the plasticizer evaporates and oxidizes, resulting in a small surface crack perpendicular to the direction of the acting pressure on the sealing ring, resulting in local dents or cracking. This failure is mainly exposed to static and dynamic seals in the air or seals in contact with other air pollutants;
② The solution uses the material with good oxidation resistance and high temperature resistance to reduce the working temperature of the system oil.
2, O-type sealing ring appears protruding, nibbling and spiral failure
① The main causes of bulge and nipping failure: the sealing gap is too large, the system pressure exceeds the sealing pressure strength or does not add the retaining ring, the sealing ring material does not meet the design hardness requirements, the sealing ring sealing groove processing size does not meet the standard provisions, the sealing ring selection is not appropriate (relative to the sealing groove size is too large). The main reasons for screw failure: the concentricity of the parts is too low, the lubrication is not enough, the sealing material is too soft, when some parts of the sealing ring are sliding and the other part is rolling, resulting in distortion or cracks;
② Solution Reduce the sealing gap, choose the appropriate size
O-type sealing ring, to ensure that the concentricity of parts meet the design requirements; The sealing grooves are processed to strict standards, using reinforced composite seals such as combination pads, using ring materials that meet the design requirements or adding a retaining ring that prevents the O-ring from being extruded.
3. The O-ring is damaged during installation
This situation often occurs in dynamic and static seals. The main reason is that there are sharp edges on the sealing groove or the imported chamfering does not meet the standard, and the installation does not apply lubricating oil, so that the sealing ring is cut by the sharp edge, distorted or stuck, and the surface has a concave (or convex) mark, peeling or peeling phenomenon;
2 Solution According to the design requirements of processing sealing groove, shall not leave sharp edge, installation in the groove and sealing ring coated with lubricating oil, when the O-ring through the thread, the thread set metal sheet or belt, so that the seal ring smoothly inserted.