Municipal drainage pumping station undoubtedly occupies a very important position in the management of urban municipal facilities. The normal running of the drainage pumping station is related to the study, work and life of urban residents. Correct management and maintenance of the drainage facilities is the key to ensuring the normal running of the drainage pumping station. Submersible sand gravel pump is a kind of sand pump machine which is often used in municipal drainage systems. Based on many years of experience, OCEAN PUMP analyzes common failures of submersible sand gravel pump, and proposes preventive measures and troubleshooting methods for users’ reference.

Seven Common Malfunction and Solutions of Submersible Sand Pump
Seven Common Malfunction and Solutions of Submersible Sand Gravel Pump
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Vibration and instability during running

A. The main reasons are as follows.

  1. The anchor bolts of the submersible sand gravel pump base are not tightened or loose.
  2. No independent support is installed to the sand water discharge pipe, and the vibration of the pipe affects the pump.
  3. The impeller mass is unbalanced, even impeller is damaged or installed loosely.
  4. The upper and lower bearings of the submersible sand gravel pump is damaged.

B. Troubleshooting measures.

  1. Tighten all anchor bolts evenly.
  2. Set up independent and stable support for the discharge pipe of the submersible sand gravel pump to prevent the pipeline flange from bearing the weight.
  3. Repair or replace the impeller.
  4. Replace the upper and lower bearings.

The submersible sand pump does not deliver sand water or the flow is insufficient

A. The main reasons are as follows.

  1. The installation height of the submersible sand gravel pump is too high, which makes the impeller immersed depth not enough, resulting in water output decrease.
  2. submersible sand gravel pump rotates in reverse.
  3. The outlet valve cannot be opened.
  4. The sand water discharge pipe is not clear or the impeller is blocked.
  5. The wear ring at the bottom of the submersible sand suction pump is severely worn or blocked by debris.
  6. The medium requires to be pumped has too high density or viscosity.
  7. The impeller falls off or is damaged.
  8. When multiple submersible sand gravel pumps share pipeline for delivery, no one-way valve is installed or the one-way valve is not tightly sealed.

B. Troubleshooting measures

  1. Control the allowable deviation of the submersible sand gravel pump installation elevation, and cannot be expanded at will.
  2. Before trial running, the motor should run idly. Checking the motor rotation direction to make it consistent with the submersible sand gravel pump rotation direction. If the submersible sand pump still rotates in reverse during use, check whether the phase sequence of the power supply has been changed.
  3. Check the valve and maintain it frequently.
  4. Clean up the blockages in pipelines and impellers, and often salvage the debris in the pool.
  5. Clean up debris or replace wear rings.
  6. Find the causes of water quality changes and manage.
  7. Reinforce or replace the impeller.
  8. Install or replace the one-way valve after checking the cause.

Excessive current causes motor overload or over-temperature protection action

A. The main reasons are as follows.

  1. The voltage is too low or too high when working.
  2. There are friction between moving and static parts inside the submersible sand gravel pump or friction between the impeller and the sealing ring.
  3. Low head and large flow cause the motor power to be inconsistent with the characteristics of the submersible sand gravel pump.
  4. The medium density or viscosity is higher.
  5. Bearing damage.

B. Troubleshooting measures

  1. Check the power supply voltage and adjust accordingly.
  2. Judge the location of the friction part sand eliminate the fault.
  3. Adjust the valve to reduce the flow, so that the motor power matches the submersible sand pump.
  4. Check the reasons of water quality changes, and improving the working conditions of the pump.
  5. Replace the bearings at both ends of the motor.
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  • Low insulation resistance.

A. The main reasons are as follows.

  1. The power cord end is immersed in water when installed, or the power cord, signal line is damaged which causes water ingress.
  2. The mechanical seal is worn or not installed in place.
  3. O-ring is aging and has no function.

B. Troubleshooting measures

  1. Replace the cable or signal line, dry the motor.
  2. Replace the upper and lower mechanical seals and dry the motor.
  3. Replace all sealing rings and dry the motor.
  • Submersible sand gravel pump pipe fitting leakage.

A. In the pipeline, there is often obvious water leakage at the pipe or flange connection. The main reasons are as follows.

  1. The pipeline itself is defective and has not pressure test.
  2. The gasket joint at the flange connection is not handled properly.
  3. Flange bolts are not tightened in a reasonable way.

B. Troubleshooting measures

  1. Defective pipe should be repaired or replaced.
  2. If the center of the butt pipe deviates too much, it should be disassembled and reassembled.
  3. After alignment, the connecting bolts should be inserted and tightened almost freely.
  4. After finishing installation, the pipeline should be tested in the pressure strength and leakage.
  • Submersible sand gravel pump rotates in reverse after shutdown.

A. If the sand pump rotates in reverse after the motor is powered off, the main reason is that the check valve or flapper in the discharge pipe is failed.

B. Troubleshooting measures.

Check before installation. The installation direction of the check valve should be correct, the center of the flapper is aligned, and the opening and closing should be flexible. Always pay attention to the check valve or flapper during operation, repair the damaged parts, or replace new check valve, flapper.

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  • Submersible sand gravel pump leaks inside.

A. submersible sand gravel pump leakage causes insulation damage, bearing water immersion, and the alarm system starts, forcing the sand pump unit to stop running. The main reasons are as follows.

  1. The dynamic seal (mechanical seal) or static seal (special seal for cable inlet, O-ring seal) of the submersible sand pump damage causes water seepage.
  2. Power cables or signal cables damage causes water seepage.
  3. Alarm signals such as water immersion, leakage, humidity, etc. starting cause the submersible sand gravel pump to stop.

B. Troubleshooting measures.

  1. Check the quality of each sealing component before installation.
  2. It is necessary to ensure that the end faces of the sealing parts are in good contact during installation.
  3. Before running, check whether the phase-to-phase and ground insulation resistance of the motor and the sensor components of each alarm system are intact.
  4. When the above failure occurs during sand pump running, replace all damaged seals and cables and dry the motor. The disassembled seals and cables must not be used again.

OCEAN PUMP is engaged in the development, production and sales of submersible sand suction pumps, submersible slurry pump, sand pumps, dredging pumps, mud pumps, slurry pumps, sand dredgers and other dredging equipment. OCEAN PUMP has in-depth cooperation with domestic mines, providing submersible sand suction pump products and related services, and has accumulated valuable experience. OCEAN PUMP has focused on submersible sand suction pumps for more than 20 years. We not only provide high-quality sand pump machine and industry solutions, but also provide on-site installation services. Please feel free to contact us for plan design and dredging equipment issues related to sand suction, sand pumping, dredging, and relay.