10 Steps to Install a Mechanical Seal Correctly and Avoid Early Failure

Most mechanical seal failures come from the installation phase, not manufacturing defects. A good seal installed incorrectly can fail after just a few hours of operation. This article presents a 10-step procedure with reasons for each step to help technicians understand what they are doing.

Pre-installation preparation

Read the manufacturer's drawings and instructions for the correct seal type, prepare clean tools, gloves, and compatible lubricants. The seal should be kept in its packaging until the last minute to protect the seal face from dust and impact.

10 installation steps

Step 1, check the pump: measure shaft deflection, seal chamber eccentricity, axial clearance, and bearing condition. Large deviations are the primary cause of seal failure.
Step 2, check the shaft and seal chamber: no scratches, burrs, rust, or worn grooves in the seal sliding area.
Step 3, clean all parts and working areas, avoiding sand, dust, and metal shavings.
Step 4, verify the seal code, material, and size with the drawing and actual medium.
Step 5, visually inspect the seal face: no cracks, chips, or scratches. Do not touch the sealing surface with bare hands.
Step 6, lubricate the seal with a compatible substance with the seal material and medium, absolutely do not use the wrong type of grease.
Step 7, install the seal on the shaft gently, do not use a hammer, avoid cutting or twisting the seal.
Step 8, place the seal at the correct installation length and tighten the seal cap evenly, diagonally, and with the correct torque.
Step 9, for cartridge seals, only remove the positioning clip after tightening and securing the shaft.
Step 10, connect the auxiliary system, vent, and fill the seal chamber with fluid before starting.

Common mistakes

Using a seal with the wrong material for the medium.
Forgetting to vent, making the seal run dry at startup.
Tightening the seal cap unevenly, making the seal face not parallel.
Installing on a worn or deviated shaft beyond the limit.

Post-installation inspection

Turn the shaft by hand to check for lightness, run a test, monitor leaks, temperature, and vibration in the first few hours. A small amount of moisture during the running-in period is normal, increasing leaks require stopping and checking.

Record keeping

Record the installation date, seal code, batch number, shaft and seal chamber measurements, to help analyze when failures occur. Training technicians to install is an effective investment. Contact SNS-VN if you need technical guidance.

References

Compiled from common technical practices in mechanical seal installation.