As an essential piece of equipment in many industrial and mining operations, a submersible slurry pump plays a critical role in moving thick, abrasive liquid mixtures from one location to another. These robust pumps are designed to handle the challenges of pumping slurries, which often contain high concentrations of solid particles suspended in liquid. However, even the most well-engineered submersible slurry pumps can experience problems that cause them to stop working properly. Let’s explore some of the common reasons why a submersible slurry pump may fail and what can be done to address these issues.

submersible slurry pump worksite
submersible slurry pump factory
submersible slurry pump drawing
submersible slurry pump control cabinet

1.What is Submersible Slurry Pump

The DMD-type submersible slurry pump is a hydro-mechanical device where the electric motor and the water pump are integrated as a single unit, submerged directly in the pumping medium. This product is designed with exceptional materials, an advanced structure, a wide flow channel, and superior discharge capability, making it an ideal choice for handling liquids containing solid particles such as sand, coal slag, and tailings.Primarily used in metallurgical, mining, and thermal power plant industries for the removal and transportation of slurry-like liquids, this series of submersible slurry pumps serves as an ideal replacement for traditional mud pumps. The design of these pumps incorporates the latest advanced technologies from abroad.

In addition to the main impeller, these pumps feature an extra agitator impeller at the bottom, which can stir up and suspend the settled sludge, enabling the pump to handle high-concentration slurries without the need for auxiliary equipment. The unique sealing mechanism ensures reliable operation, significantly extending the pump’s service life.The electric motor is equipped with overheating protection, and various additional protection devices, such as proximity sensors, can be added upon the user’s request, allowing for long-term safe operation even in harsh working conditions.

2. Submersible slurry pump operating conditions

2.1 Power Supply Flexibility

The standard power supply for OCEAN Pump‘s submersible slurry pumps is a 50Hz/380V three-phase AC power source. However, to cater to the diverse needs of customers across different countries, OCEAN Pump can customize the frequency and voltage to suit various requirements, such as 50Hz, 60Hz, 440V, 660V, and even six-wire power supplies.

2.2 Fluid Temperature and Composition

The maximum fluid temperature that the pump can handle is 40°C, and the fluid must not contain any flammable or explosive gases.

2.3 Solids Concentration and Density

The maximum volumetric concentration of solid particles in the fluid is 30%, and the maximum fluid density is 1.2 kg/L.

2.4 Submergence Depth and Cooling

OCEAN Pump’s submersible slurry pumps can now operate at depths of up to 200 meters, surpassing the previous 20-meter limitation. The minimum submergence depth is the bottom of the pump casing. For applications where the motor does not need to be fully submerged, a cooling shroud can be added to the motor section.

2.5 Orientation and Operation

The pump unit should be installed in a vertical orientation for optimal performance. The recommended operating mode is continuous operation.

Note: If the site conditions do not meet the specifications outlined above, please inform OCEAN Pump at the time of order placement, and the pumps can be customized to meet the specific requirements. Contact Lingda Kong

3.Installation of Submersible Slurry Pump

3.1Pre-installation Inspection and Precautions

3.1.1 The operating environment should meet the usage conditions.

The actual flow rate and head should match the performance curve. The optimal flow range is 80% to 120% of the rated flow rate. Exceeding 120% of the rated flow rate may cause serious damage to the unit.

3.1.2  Check the assembly quality of the unit, whether the fasteners are loose, whether the cables are damaged, and whether the power supply and electrical equipment are reliable.

3.1.3 Check whether the power voltage and frequency are consistent with the nameplate requirements, and whether the starting, control, and protection facilities are in good condition.

3.1.4 Check whether the oil level in the oil chamber is appropriate. When the unit is in a vertical position, the oil level should reach the oil filling port, otherwise the appropriate amount of turbine oil should be added.

3.1.5 For submersible slurry pumps with cooling jackets, ensure continuous injection of clean cooling water when starting the pump, and ensure that the drainage port is unobstructed. The cooling water should flow in from the lower side of the cooling device and out from the upper side.

3.1.6 Measure the insulation resistance of the motor in the cold state using a 500V megohmmeter, which should not be less than 50MΩ.

3.2 Precautions

During normal operation of the unit, the power voltage, operating current, pump flow rate, and pump vibration should be observed at all times. The unit should be immediately shut down and inspected if any of the following occurs:

  1. The operating current exceeds the rated current.
  2. The flow rate decreases by 20% at the rated head, or the pump intermittently stops discharging water.
  3. The motor part of the pump without a cooling device is exposed above the water surface, or the volute part of the pump with a cooling device is exposed above the water surface.
  4. The power voltage is too high or too low (higher than 400V or lower than 340V).
  5. The motor insulation resistance is less than 0.5MΩ.
  6. The unit has obvious vibration and noise.

3.3 Installation

3.3.1  Electrical wiring:

  1. The power cable of the electric pump has four cores, three power wires and one ground wire; the electric pump equipped with a protective device has a corresponding control cable; the core wires of the electric pump cable have identification plates indicating different functions, see the table below:
TypeSymbolCore nameCore functionCable lengthThe cable core wire to the grounding wire insulation resistance
Power cableU、V、WThree phase power coreControl of three-phase power core10 m
For grounding wireConnected to groundTogether with casing
Control cableWCThermal protection wireTo the thermal protector10 m0
XLLeakage protection wireTo the float switch

Strictly follow the wiring of the core wires marked on each signboard and the terminal with the same mark on the control cabinet. Use a multimeter to check that the resistance value of each core wire and each ground wire should meet the requirements of the above table. The ground wire must be reliably grounded.

  1. The insulation resistance should be monitored at any time during the installation process. After going down the well, the insulation resistance of the motor should not be less than 5ΜΩ; the electrical equipment can be started only after it is connected.
  2. Turn on the power supply. If the pump outputs less water, the electric pump may be connected in reverse. Stop the machine and replace any two connectors of the three power lines.

3.3.2 Installation method

The installation method is mobile installation. The electric pump is suspended vertically into the water and placed stably. Then the cable is tied and the pump outlet is connected to the pipeline. This method is simple to install and easy to move.

4. Fault Analysis and Troubleshooting of Submersible Slurry Pumps

NO.FaultsPossible CausesSolution
1The Current is over high and exceeds the rated current1.The pump is friction-resistant1.Adjusting the clearance
2.The pump lift of the device is too low and the pump is operated in large flow rate2. Controlling the flow rate by the valve or replacing a pump with proper pump lift
3. The bearing is damaged3.Replacing the bearing
2The motor does not rotate and has noise when started.1. The voltage is too low1. Adjusting the voltage to the rated value
2. The motor is rotated with single phase2.Checking the lines and connecting the broken lines
3. The pump is blocked by foreign matters3.Removing the foreign matters
4.The impeller rubs with the inner pump over or the water suction plate4.Adjusting the clearance of the impeller to normal value
3The pump does not output water or output a small quantity of water1.The impeller rotates reversely1.Changing any two phase power cords
2.Water strainer is blocked2. Removing the blockage
3.The water inlet is exposed out of the water surface3.Adjusting the pump to submerged the pump
4.Water pipe leaks or are leaked4.Replacing the water pipe or removing the sludge
5.The actual pump lift is too highSelecting a pump with proper pump lift
4The insulation resistance is reduced to below 0.5 MΩ1.Cable connector is damaged1.treating the cable connector again
2.The stator winding insulation is damaged2.Replacing the stator winding
3.Water enters the cavity of the motor3.removing the water content and drying the winding
4.The cable is damaged4.repairing the cable
5The pump has unstable operation and serious vibration1.The impeller is worn seriously1.Replacing the impeller
2.Impurities block the rotating parts2.Clearing the impurities
3. The bearing is damaged.3.Replacing the bearing

5. In conclusion

there are a variety of reasons why a submersible slurry pump may stop working, ranging from wear and tear on components to electrical, hydraulic, and environmental issues. By understanding these potential problems and implementing a comprehensive maintenance and inspection program, industrial and mining operations can help ensure the reliable and long-lasting performance of their critical slurry pumping equipment.

Lingda Kong
Tai’an Ocean Pump Co.,Ltd
Mobile/Viber/Whatsapp/Wechat: +86 18562293317