Pусский
There are dozens of types of carbon graphite available, with different properties. It is necessary to understand the grades, properties and sources of supply of various carbon graphites, and select them reasonably. The following deals with how to choose such materials based on introduced mechanical seal failure from—— high wear.
At present, there is a general tendency in selection of materials, that is, harder carbon graphite is used regardless of working conditions of mechanical seal, because it is believed that the higher the hardness, the more wear-resistant the carbon graphite.
However, this is not the case under some conditions. For example, for media with poor lubricity, no lubricity, or other conditiojns that are prone to dry friction, such as light hydrocarbon media, hard M106k as material of friction pair wears more, while soft high-purity electrochemical graphite has less wear.
Soft graphite has excellent low-friction properties. It is due to the good self-lubricating properties of graphite crystals：During operation of the said mechanical seal, a very thin graphite film is transferred to surface of mating part, so that friction surface is lubricated, friction coefficient is reduced, and wear is reduced.
On another occasion，when the paired material is sprayed ceramics, it is advisable to choose medium-hard graphite.
If content of solid particles in medium exceeds 5%, carbon graphite should not be used as a paired material for single-end mechanical seals, nor should it be used as a main seal ring in a tandem mechanical seal.Otherwise,the said seals will experience high wear.
At present, there is a general tendency in selection of materials, that is, harder carbon graphite is used regardless of working conditions of mechanical seal, because it is believed that the higher the hardness, the more wear-resistant the carbon graphite.
However, this is not the case under some conditions. For example, for media with poor lubricity, no lubricity, or other conditiojns that are prone to dry friction, such as light hydrocarbon media, hard M106k as material of friction pair wears more, while soft high-purity electrochemical graphite has less wear.
Soft graphite has excellent low-friction properties. It is due to the good self-lubricating properties of graphite crystals：During operation of the said mechanical seal, a very thin graphite film is transferred to surface of mating part, so that friction surface is lubricated, friction coefficient is reduced, and wear is reduced.
On another occasion，when the paired material is sprayed ceramics, it is advisable to choose medium-hard graphite.
If content of solid particles in medium exceeds 5%, carbon graphite should not be used as a paired material for single-end mechanical seals, nor should it be used as a main seal ring in a tandem mechanical seal.Otherwise,the said seals will experience high wear.
