Precautions for Use of Mechanical Seals

The sealing effect and service life of mechanical seals depend not only on reasonable selection, but also closely on installation, operation and maintenance. Key precautions are as follows:

I. Selection Precautions

Select appropriate seal type and materials according to medium properties including pressure, temperature, corrosiveness and particle content, to avoid sealing failure caused by improper selection, such as adopting unbalanced seals for high-pressure conditions or ordinary carbon steel materials for corrosive media.

Choose matching seal specifications according to equipment rotating speed and shaft diameter, to ensure tight fitting of sealing faces without gaps or deflection.

Double-end mechanical seals with matched barrier fluid systems must be adopted for flammable, explosive, highly toxic and volatile media, to prevent leakage accidents and ensure safe sealing.

II. Installation Precautions

Before installation, inspect all components of the mechanical seal. Check for scratches, damage and oil stains on rotating and stationary seal faces, aging or deformation of sealing rings, and flexibility and integrity of springs.

Keep the shaft diameter surface clean, smooth and free of burrs and scratches to avoid damaging sealing rings and faces. Do not strike or collide rotating and stationary rings during installation to prevent face breakage.

Adjust seal clearance to ensure uniform fitting of rotating and stationary faces, and keep spring compression within design specifications. Excessive compression accelerates face wear, while insufficient compression causes leakage.

Manually rotate the equipment shaft after installation to check for jamming and abnormal friction noise, ensuring flexible operation of the mechanical seal.

III. Operation Precautions

Before startup, confirm normal operation of cooling and lubrication systems for the seal chamber. Sufficient lubrication and cooling are required to prevent dry friction and burning damage to sealing faces.

Increase rotating speed gradually during startup to avoid impact and abrasion on seal faces caused by sudden speed surge. When shutting down, stop medium delivery first, and turn off cooling and lubrication systems only after the equipment stops completely.

Regularly check for leakage such as dripping and spraying during operation. Stop the machine immediately for inspection once leakage occurs, and troubleshoot causes including face wear, sealing ring aging and spring failure.

Avoid prolonged idle operation. Without medium lubrication, dry friction and face sintering will easily damage mechanical seals.

Keep medium temperature and pressure within designed ranges. Prevent sharp fluctuations in temperature and pressure to avoid face deformation and sealing ring aging.

IV. Maintenance Precautions

Clean the seal chamber regularly to remove impurities and deposits, preventing foreign matters from entering seal faces and causing abrasion and blockage.

Inspect vulnerable parts including sealing rings and springs periodically. Replace aged, deformed or broken parts promptly to avoid leakage caused by component failure.

For double-end mechanical seals, regularly check liquid level and purity of barrier fluid. Replenish and replace barrier fluid in time to maintain its cooling, lubrication and buffering functions.

Protect mechanical seals during long-term shutdown. Clean residual medium on seal faces and apply anti-rust oil to prevent face corrosion and sealing ring aging.

Follow equipment operation manuals during maintenance. Illegal disassembly and assembly are prohibited to avoid damage to seal components.

V. Other Precautions

Installation and maintenance shall be performed by professional technicians to prevent sealing failure due to improper operation.

Store mechanical seals in dry, ventilated and clean environments. Avoid moisture, oil contamination and dust to prevent sealing ring aging and face rusting.

Frequent leakage and excessive wear may be caused by equipment faults such as excessive shaft runout and damaged bearings. Do not only replace seals without addressing root causes.