Points to Note for Disassembly and Assembly of Mechanical Seal Parts

Mechanical seals are one of the most effective sealing methods in modern rotating machinery. Their precision machining requirements ensure the normal operation of the moving and stationary rings under high-pressure environments. However, improper disassembly and assembly can lead to mechanical seal parts being damaged, thus affecting the sealing effect of the equipment. This article will detail the precautions for mechanical seal parts during disassembly and assembly to ensure the stability and reliability of their performance.

Precautions for Disassembling Mechanical Seal Parts

When disassembling mechanical seal parts, it is crucial to follow the correct steps and techniques:

Avoid Using Tools That Damage Sealing Components

When disassembling mechanical seals, it is strictly forbidden to use tools like hammers or chisels, as they may cause irreversible damage to the sealing components.

Handle Dual-End Mechanical Seals with Care

If there are mechanical seals on both ends of the pump, extra caution is needed during disassembly to ensure no sealing components are overlooked on either end.

Replace Loose Moving and Stationary Rings

For used mechanical seals, if the gland is loose causing the sealing surface to move, the moving and stationary ring components should be replaced immediately rather than simply retightening. This is because the original operating trajectory of the friction surface will change after loosening, thus affecting the sealing effect.

Clean Adhesions

Before disassembly, if dirt or aggregates are found on the sealing components, they should be cleaned thoroughly to avoid secondary contamination during disassembly.

Precautions for Installing Mechanical Seal Parts

Mechanical seal parts installation also requires meticulous attention to ensure every step is in accordance with standards:

Check the Quantity and Condition of Seal Parts

Before installation, be sure to check whether all sealing components are complete and carefully observe if the moving and stationary rings have dents, cracks, or deformations. If problems are found, repair or replace them immediately.

Correct Chamfers of the Shaft Sleeve and Gland

Ensure that the chamfers of the shaft sleeve or gland meet the requirements. If not, they must be adjusted to ensure the normal operation of the mechanical seals.

Clean Contact Surfaces

All mechanical seal components and their related contact surfaces must be thoroughly cleaned with acetone or anhydrous alcohol before installation. Maintain cleanliness during the installation process, especially for the moving and stationary rings and auxiliary sealing components, which must be free from impurities and dust. Additionally, the surfaces of the moving and stationary rings should be coated with a layer of clean machine oil or turbine oil to reduce friction.

Tighten Bolts Evenly

When tightening the gland, ensure the coupling is aligned. Bolts should be tightened evenly to avoid skewing the gland end face. Use a feeler gauge or special tool to check the error, ensuring it does not exceed 0.05 mm.

Check the Mating Gap and Concentricity

The mating gap between the gland and the shaft or shaft sleeve outer diameter must be even. Use a feeler gauge for checking, and the allowable difference should not exceed 0.1 mm.

Control the Spring Compression Amount

The spring compression amount should be strictly implemented according to regulations, with the error not exceeding±1.00 mm. Excessive compression will accelerate end face wear, while too little might result in poor sealing performance. When assembling springs, ensure flexible movement within the spring seat, and if using a single spring, ensure the spring's winding direction is opposite to the shaft’s rotation direction.

Ensure the Flexibility of the Moving Ring

After installing the moving ring, it should remain flexible, able to automatically spring back when pressed towards the spring, ensuring its sealing performance.

Installing the Stationary Ring Sealing Ring

When installing the stationary ring sealing ring, it should first be fitted onto the back of the stationary ring, then installed into the sealing end cap. Take care to protect the end face of the stationary ring and ensure perpendicularity to the end cap centerline, while aligning the anti-rotation groove at the back of the stationary ring with the anti-rotation pin, avoiding direct contact.

Use Specialized Tools

During installation, using tools to directly hit sealing components is strictly prohibited. If striking is necessary, always use specialized tools to prevent damage to the sealing components.