What are the steps to install a mechanical seal?

Mechanical seal installation steps (core: clean, align, protect seal faces, control preload) are as follows, suitable for common single-face internal-mounted seals:

1. Pre-installation preparation & cleaning

- Confirm the seal model matches the equipment (shaft diameter, pressure, medium), and check parts for defects (no scratches on seal faces, spring intact, O-rings elastic).
- Thoroughly clean the shaft surface, seal chamber, and mounting parts (remove rust, debris, old seal residue) to avoid damaging seal faces.
- Apply compatible lubricant (e.g., clean oil for oil media, glycerin for water media) to the shaft, O-rings, and seal face (prevent dry friction during installation).

2. Assemble the seal assembly

- Install auxiliary seals (O-rings, V-rings) onto the moving ring or stationary ring: avoid twisting, stretch slightly to fit smoothly (do not use sharp tools to prevent cutting).
- Install the spring/bellow onto the moving ring seat, ensuring it’s correctly positioned (no jamming, uniform force distribution).
- Lightly fit the moving ring and stationary ring (seal faces face each other) to check for smooth contact (no jamming or tilting).

3. Install the seal into the equipment

- Slowly slide the assembled seal onto the shaft: keep the seal coaxial with the shaft, avoid forcing or tilting (prevent scratching seal faces or O-rings).
- Fix the stationary ring to the seal chamber: tighten the set screws evenly (do not over-tighten to avoid deforming the stationary ring).
- Ensure the moving ring can move axially freely (spring compression is adjustable, no jamming from foreign objects).

4. Adjustment & final inspection

- Check the spring compression: follow the manufacturer’s specifications (too loose → poor sealing; too tight → excessive wear). Rotate the shaft by hand to confirm smooth operation (no stuck or abnormal resistance).
- Recheck coaxiality: ensure the shaft has no obvious eccentricity or runout (use a dial indicator if needed, runout ≤0.05mm for general pumps).
- Wipe off excess lubricant, and confirm no debris is left in the seal chamber.

5. Post-installation test

- Conduct a static leak test: fill the seal chamber with the medium (or clean water) and check for leakage at the seal face and auxiliary seals.
- Start the equipment at low speed first: observe for abnormal noise, vibration, or leakage. Gradually increase to normal speed, and monitor for 10–30 minutes (stable operation with no continuous dripping is qualified).