Disassembly and maintenance methods for split-case double-suction pump bearings

As a core fluid conveying device, single-stage split-case double-suction pumps are widely used in various industrial fields such as water conservancy, chemical engineering, and municipal engineering. During long-term operation, malfunctions are inevitable. Timely and standardized maintenance and rapid troubleshooting are crucial for ensuring the continuous and stable operation of the equipment and extending its service life. This article will detail the bearing removal method for single-stage split-case double-suction pumps, as well as key maintenance requirements before starting, during operation, and after shutdown.

• Disassembly method for the bearings of a split-case double-suction pump

The removal of pump bearings should follow standardized procedures based on variations in the installation structure, with the core principle being to prevent damage to the bearings or shaft due to uneven stress.

Shaft end removal method

Prioritize using a dedicated bearing puller: Securely clamp the puller jaws onto the inner ring of the bearing, then apply even axial force to smoothly slide the bearing off the shaft. This method maximizes bearing protection and improves shaft accuracy.

If a puller is unavailable, a "wedge-shaped copper rod" can be used (copper prevents scratching of components): Position the copper rod at an angle against the edge of the inner ring, tap it evenly with a hammer, and then slowly rotate the copper rod around the inner ring to ensure even force distribution until the bearing is completely removed.

Alternative auxiliary support method: Symmetrically clamp two steel plates of equal thickness beneath the inner ring of the bearing, stably support the shaft with a cylinder/support (to accommodate the shaft), place a thick wooden/copper plate on top of the shaft (to cushion the impact), and tap vertically to dislodge the bearing axially.

End Cap Disassembly Method

For pumps where the fit tolerance between the end cap bearing bore and the bearing outer ring is smaller than the fit tolerance between the bearing inner ring and the shaft, the bearing should be removed together with the end cap. Remove the bearing from the end cap using the following steps:

1. Place the end cap with the socket facing upwards; place wooden blocks on the outside of the bearing bore (avoiding the bearing itself) to protect the end cap.
2. Use a copper rod or a special punch (with a diameter slightly smaller than the bearing outer ring) to press vertically on the end face of the outer ring, then tap downwards evenly with a hammer until the bearing pops out of the end cap bore.

• Maintenance methods for the bearings of split-case double-suction pumps

Pre-startup inspection procedures

Complete the following checks to ensure safe startup and stable operation:

1. Manually and slowly rotate the coupling or pulley to confirm that the rotation direction matches the design requirements. Ensure smooth rotation without jamming, abnormal vibration, or internal foreign objects; the bearings should rotate freely.
2. Check the belt drive tension (too loose will cause slippage; too tight will accelerate bearing wear) and confirm that the coupling bolts are tightened.
3. Check that all fasteners and connectors are securely connected to prevent loosening due to vibration during operation.
4. Clear any debris around the pump unit to ensure unobstructed operating space.
5. Confirm that the suction pipe immersion depth meets the design standards to avoid air ingress and dry running.
6. For pumps equipped with a discharge valve: Close the valve before starting (to reduce water resistance and motor starting load), and open the valve immediately after starting to resume normal operation.

Key monitoring points during operation

After startup, continuously monitor operating parameters and equipment status; immediately address any abnormal situations to prevent fault escalation:

Ensure that monitoring instruments (ammeters, pressure gauges, etc.) display stable readings. The operating current must remain within the motor's rated range, and the pressure gauge reading should remain within the design pressure range without significant fluctuations.
Confirm that the discharge flow rate and pressure meet operating requirements; check for leaks at sealed joints (flange connections, shaft seals).
Shaft seal inspection:
Packing seal: Minimum leakage is allowed (10-20 drops per minute).
Mechanical seal: Leakage ≤ 10 mL/h (≈3 drops per minute); if this value is exceeded, adjust immediately.

Bearing temperature monitoring: Rolling bearing temperature ≤ 75℃; sliding bearing temperature ≤ 70℃. If the temperature continues to rise, immediately shut down the equipment and check the lubrication or assembly.
Monitor the water pump's operation, paying attention to any abnormal noises (sharp sounds, knocking sounds) or uneven vibrations. Note if the flow rate suddenly drops (this indicates suction pipe blockage or impeller scaling).
Check the immersion depth of the suction pipe in real time; if the water level changes, adjust it promptly to maintain suction efficiency.
Regularly clean floating debris from the suction pipe's trash rack to prevent blockage.

Shutdown and post-shutdown maintenance requirements

Shutdown Procedure: Follow the principle of "close the valve first, then shut down the pump"-close the discharge valve before cutting off the motor power to prevent water backflow from damaging the impeller/bearings.
After each shutdown: Wipe off any oil/water residue from the pump body and piping to keep them clean and facilitate the detection of potential leaks or corrosion.
Winter Operation: Immediately drain all water from the pump body and piping after shutdown to prevent freezing damage to components (pump body, impeller, seals).
Seasonal Maintenance:

1. Disassemble and inspect the bearings for wear; replace aged grease.
2. Remove scale and debris from the impeller and flow passages.
3. Check the integrity of the seals; replace if necessary.
4. Store the equipment properly and take measures to prevent dust and rust.