Common thermal damage to the mechanical seal

Centrifugal pump mechanical seal failure due to overheating, failure is thermal damage, the most common failure of a face thermal heat damage deformation, thermal cracking, blister scars, carbonization, the elastic element missing bombs, rubber aging, permanent deformation , cracks, etc.
Heat pump seal face distortion and local thermal deformation of the overall thermal deformation. Sealing end face sometimes find many small isolated hot spots and discoloration area, indicating that seals in high pressure and heat under the influence of local deformation occurs distortions; sometimes found sealed end surface of a symmetric discrete bright band, which is mainly is due to irregular cooling, causing the end of local thermal deformation. Sometimes found inside the seal face wear is very serious, the larger the radius the more shallow contact marks until indiscernible. The inside edge of the seal ring may appear the phenomenon of edge chipping and jumped. The shaft rotates, the sealing continued leakage, and the shaft is stationary, not leak. This is because the seal is in operation, sufficient cooling the outside, while the inside severe frictional heating, thermal deformation is greater than the inside outward to thermal deformation, thermal deformation is formed inside the contact-type (n-cone angle) end.
Carbide, engineering ceramics, brittle materials such as carbon graphite high security cable seals ring, and sometimes there will be a radial end surface cracks, so that the sealing surface leakage increased rapidly, rapid wear on the couplings, which are mostly due to the sealing surface is dry friction, cooling suddenly Friction causes interruption rapid accumulation of heat damage to the formation of a thermal failure.
In the high temperature environment of the mechanical seal, graphite rings often find the surface pits, scar blocks. This is because when the resin-impregnated graphite ring exceeds the allowable temperature, the resin will decompose to form carbide precipitates durum and volatiles, scar formation, which greatly increase the friction, and to surface damage with high leakage.
High temperatures may reduce the flexibility of the elastic member, the sealing face of the closing force due to inadequate seal faces serious leak. High temperature metal bellows failure of such mechanical seal bomb that is a common and typical failure modes. Failure to avoid such an effective way to choose the right material and its bellows appropriate heat treatment.
High-temperature rubber id cable ties aging, cracking and permanent deformation of an important reason. Rubber aging, the performance of the rubber hardens, strength and elasticity, there will be severe cracking, resulting in the loss of sealing performance. In the high temperature fluid, the rubber ring to continue curing danger to loss of elasticity and eventually leak. Among the long-term high temperature seal, will become the same as the shape of the groove, the temperature remains constant, but also the seal; but when the temperature is reduced, the ring was quickly contraction leak leakage channel is formed. Therefore, we should pay attention to the use of various types of plastic temperature, and should avoid prolonged use in extreme temperatures.