Rotary shaft seals, or oil seal, essential for the functionality of a rotating shaft
The dynamic seal is used by the contact between the labyrinth of the gasket and the shaft, exerting a force called "radial load". The contact area between the two elements is fundamental, and is guaranteed by the spring and by the undersizing of the internal diameter of the sealing ring.
What to choose and when to change
To withstand high pressures it is necessary to give rigidity to the sealing ring. This result is obtained thanks to the presence of a metal insert, which can be completely or partially covered with elastomer.
To obtain a seal at the point of contact between the rotating shaft and the sealing ring, a thin film of fluid must be created, which guarantees lubrication and durability of the seal itself. The elements that guarantee the creation of the fluid film are the undersizing of the internal diameter of the lip and its spring.
LIP AND ROTATING SHAFT
The lip of the sealing ring is essential to guarantee the protection of the sealing system. To compensate for lip wear, it is reinforced with a spring, usually in stainless steel, which guarantees correct contact between the lip and the shaft. The hardness of the lip must be proportional to the linear speed of the shaft to reduce its degradation.
The choice of the material to be used is fundamental to prevent rapid wear and malfunction of the sealing system. The gasket must be replaced when the lip no longer guarantees the containment of the fluids.