ZJQ Submersible Slurry Pump Impeller Clogging: 4 Cleaning Methods

Subtitle: From Minor Wrapping to Severe Jamming – Practical Techniques to Quickly Restore Pump Performance

Introduction

In river dredging, mine dewatering, tailings transport, and similar applications, ZJQ submersible slurry pumps often experience impeller clogging due to fibrous materials, large particles, or high-concentration settled solids. Once clogged, flow drops sharply, current becomes abnormal, and in severe cases, the motor may burn out. Many users are unsure how to respond and may repeatedly restart the pump blindly, causing further damage.

As a professional slurry pump manufacturer, this article summarizes 4 cleaning methods for ZJQ submersible slurry pump impeller clogging – from the safest “reverse flushing” to the necessary “disassembly cleaning” – helping you quickly restore pump performance based on the severity of the clog.

1. Assessing Clog Severity

Before cleaning, determine the severity of the clog to choose the appropriate method:

2. Method 1: Forward/Reverse Flushing (For Minor Wrapping)

Principle: Briefly reverse the motor to use reverse water flow to dislodge fibers or loose particles wrapped around the impeller.

Steps:

1. Disconnect power and wait for the motor to stop completely (~30 seconds)

2. Swap any two phases of the motor wiring to achieve reverse rotation

3. Jog start (run for 2-3 seconds) and observe current and sound

4. If clog is cleared, restore wiring to forward rotation and start normally

5. If ineffective, do not repeat excessively (allow at least 30 seconds between attempts)

Precautions:

• Each reverse run must not exceed 5 seconds; longer runs may damage the mechanical seal

• Only effective for fibrous, soft debris; not for large particle jamming

• Maximum 3 reverse attempts; if ineffective, switch to another method

3. Method 2: Lift Out + High-Pressure Water Jetting (For Moderate Clogging)

Principle: Lift the pump out of the pit and use a high-pressure water jet from the suction side to flush out debris.

Steps:

1. Disconnect power and safely lift the pump using proper lifting equipment

2. Place the pump horizontally with the suction facing upward

3. Use a high-pressure water jet (5-10 MPa) aimed at the impeller blade gaps, flushing repeatedly

4. Rotate the impeller (using a pry bar if needed) to flush all flow passages

5. Confirm smooth rotation, then reinstall and submerge

Precautions:

• Keep cable connections upward to prevent water from entering the terminal chamber

• If the pump has drain plugs, open them to empty standing water

• Hand-turn the shaft after flushing to confirm no resistance before powering on

4. Method 3: Disassembly Cleaning (For Severe Jamming)

Principle: Remove the pump casing and extract the impeller for thorough cleaning. This is the most complete method.

Steps:

1. Disconnect power, lift out the pump, and place on a maintenance stand

2. Loosen the bolts connecting the casing to the motor frame and remove the casing

3. Remove the impeller (if stuck, tap the impeller hub gently with a rubber mallet; never pry hard)

4. Remove all debris from impeller passages and casing (cut fibers with scissors, remove hard chunks)

5. Inspect impeller vanes and seal ring for damage; replace if necessary

6. Reassemble in reverse order, tightening bolts to specified torque

7. Hand-turn to confirm smooth rotation, then test run

Tools required: Wrench, rubber mallet, screwdriver, scissors, cleaning cloth

Precautions:

• Mark bolt positions before disassembly to ensure even torque during reassembly

• Check if the mechanical seal was damaged by dry running during the clog (replace if oil chamber shows water ingress)

• Replace O-rings during reassembly to ensure sealing

5. Method 4: Soaking Softening (For Solidified Deposits)

Principle: When the pump has been idle for a long time and slurry has dried and solidified between the impeller and casing, use chemical or physical soaking to soften deposits.

Steps:

1. Lift out the pump and remove the casing (or soak the entire assembly if casing cannot be removed)

2. Submerge the impeller section in clean water (add a small amount of dispersant if available) for 24-48 hours

3. Rotate the impeller every 6 hours to help loosen deposits

4. After deposits soften, use a high-pressure water jet or manual tools to clean

5. Dry thoroughly before reassembly

Applicable scenarios:

• Tailings pumps idle for more than 7 days

• High-concentration slurry dried into hard blocks inside the pump

• Normal flushing cannot loosen deposits

Precautions:

• Do not use strong acids or alkalis for soaking, as they may corrode seals

• After soaking, thoroughly dry the motor terminal chamber to prevent water ingress

6. Cleaning Method Selection Quick Reference

7. Daily Preventive Measures Against Impeller Clogging

Conclusion

Impeller clogging in ZJQ submersible slurry pumps is a common issue, but with proper diagnosis and cleaning methods, most problems can be resolved within 30 minutes. Use reverse flushing for minor wrapping, high-pressure water jet for moderate clogging, disassembly for severe jamming, and soaking for solidified deposits. Mastering these 4 methods will help you quickly restore pump performance and avoid motor burnout and prolonged downtime.

As a professional slurry pump manufacturer, we recommend establishing a daily inspection routine to take preventive action before clogging occurs. For on-site technical guidance or spare parts support, please contact our engineering team.