The Functions and Advantages of Mechanical Seals
Jan 27, 2026
Introduction
Sealing performance is of paramount importance for rotary joints, as it directly determines their normal operation and service life.
Common sealing structures include mechanical seals, clearance seals, and contact seals, among which mechanical seals are the focus here.
The core principle of mechanical seals is as follows: the pre-tightening force of elastic elements combined with medium pressure keeps the rotating ring rotating synchronously with the shaft and the stationary ring fixed on the housing, ensuring the permanent precision fit of their sealing end faces. This design converts the easily leaky axial gap into a tightly fitted end face that is far less prone to leakage, achieving highly efficient sealing.
Mechanical seals can be further classified into balanced mechanical seals, hydrostatic seals, hydrodynamic seals or multi-stage combined seals.
Key Functions & Advantages
Superior Sealing Performance
With an extremely low leakage rate (far outperforming packing seals), it meets the core medium sealing requirements of rotary joints and effectively prevents the leakage of coolant, water, gas and other media.
High Wear Resistance
The rotating and stationary rings are made of wear-resistant materials such as SIC, cemented carbide and graphite, which are perfectly adapted to the high-speed rotation working condition of rotary joints and ensure an extended service life.
Wide Operating Condition Adaptability
It is suitable for high pressure, high speed and various corrosive media (water, coolant, CO2 gas, etc.), satisfying the application requirements of rotary joints of different specifications.
Low Maintenance Cost
Only the sealing pair (rotating and stationary rings) needs to be replaced after wear, without the need for complete disassembly of the rotary joint, which facilitates the maintenance of industrial equipment.
Brief Summary
Mechanical seals are the core components that enable rotary joints to achieve high-speed, high-pressure and leak-free sealing. The SIC/graphite seal ring assembly used in our products is the most essential rotating-stationary ring pairing of mechanical seals, and it is also the key to ensuring the excellent sealing performance of rotary joints.
