What are the Causes of Damage to the Slurry Pump?
Reverse Rotation
This occurs when the slurry pump‘s wiring is faulty, causing the motor to run backward. Very little water is moved when this happens, but the pump is severely damaged, polishing the impeller and causing cavitation.
Dry Running
This is when the water level decreases to the point where the pump can no longer extract a sufficient amount of water and/or begins to cause significant disturbance in the water. This causes cavitation*, which damages the impeller and diffuser and quickly destroys the pump. It also causes the rubber seals to dry up and crack, allowing water into the motor.
Running on the Right on the Curve
This occurs when there is less vertical head than the pump is designed to handle, causing the pump to be inefficient. At its most severe, this creates suction cavitation, characterized by the sound of pumping marbles and pitting around the impeller’s center.
Specify Gravity
Submersible pumps are not designed to handle high solids levels and will likely fail rapidly in slurry applications. Exceeding 1.1 – 1.2 specific gravity is not permitted; this creates a sand slurry.
Cable Damage
This includes internal damage, frequently unnoticed when the cable is jolted externally. It is critical to determine if a thread has been gashed or ripped. The seal configuration where the line enters the pump body is a weak point, and the air seal is easily broken. A few drips of moisture can cause the pump to malfunction.
Dead Head
The pump has a greater vertical head than it was designed for because a valve on the discharge has been closed. This results in discharge cavitation, which is characterized by the sound of marbles being pumped and pitting around the impeller tips and the inside of the pump casing. This can cause the pump shaft to shatter in extreme cases.
Not Allowing for Discharge Pumping
Friction loss is created by discharge piping, and this calculation must be considered when designing submersible pumps. Otherwise, as mentioned above, it will result in deadheading.
Cavitation is the production and concentration of bubbles around the impeller of a pump. As liquids of any viscosity are transported through and around a pump system, this tends to develop. When one of these tiny bubbles collapses or bursts, a high-energy shock wave is created inside the liquid. Consider tossing a stone into a pond. The circular ripples produced by this mechanism resemble exploding cavitation bubbles. The difference here is that due to the sheer amount of bubbles producing these shock waves, the impeller and other pump components are damaged.
Blocked or Jammed Impeller
A jammed impeller will almost certainly trip the electric motor and cause mechanical damage. Use an appropriate filter and suspend the pump/intake pipe off the floor to decrease the chance of fouling or blockage.
Pressure Drops or Spikes
The wearing process will accelerate if your pump has to deal with pressure decreases or spikes. Fluid leakage will increase due to changing operational circumstances. Rubber lip seals are more forgiving under these conditions and less prone to this problem.
Shocks and vibrations
Too many shocks and vibrations might cause the shaft to have a lot of axial and radial play. This results in poor alignment and increased fluid leakage. Improper alignment, operating conditions, or working past the pump’s optimum efficiency point (BEP) can cause excessive vibration and shorten the seal’s lifespan. If your pump is subjected to heavy-duty conditions (such as dredge pumps), ensure that your seal can withstand above-average axial and radial work.
What are the common problems of Slurry Pumps?
A slurry pump is a sand pumping apparatus that uses centrifugal force to boost the energy of solid and liquid mixed media (the rotation of the pump’s impeller). The mud slurry pump transforms electrical energy into the medium’s kinetic and potential energy. It mainly applies to mining, power plants, dredging, metallurgy, chemicals, building materials, and petroleum industries.
How to Fix Problems of Slurry Pumps?
How to Repair Slurry Pump
If the slurry pump is utilized for an extended period, the equipment may deteriorate due to the external environment and other reasons. If the wear is minor, the dredge pump machine can continue to operate. If the equipment suffers significant wear, the pump casing may split, causing damage to the entire equipment body. At this point, we must repair the damaged piece of equipment.
Before fixing the abrasion on the pump casing, the slurry pump impeller must be detached, leaving room for operation and performing dust-proof and safety precautions on site.
First, assess the severity of the pump casing wear before deciding how to repair it.
Pre-weld where there is leakage in the mud slurry pump to strengthen the leakage spots and weak areas, and then rinse the pump casing with a significant amount of clean water to remove any leftover paint on the surface.
Finally, sandblast the pump casing surface to remove the oxide layer, roughen the surface of the sand pump casing repair, and strengthen the bonding force of the repair material.
How to Ensure the Proper Maintenance of Your Slurry Pump
Check the Belts
If your slurry pumps are belt operated, please check the tension at least once a quarter. Overly tight straps will damage the light series motor bearing; if that bearing fails, the thrust bearing in the pump will begin to fall. Extremely loose belts cause poor performance and slippage, resulting in sheave damage.
Make use of a Gates tension tester. It is a straightforward tool that comes with instructions. If the belts are too loose, an experienced ear can detect them. They’ll make a flapping sound. Overly tight straps may cause the motor to pull high amps or raise bearing temperatures before bearing failure occurs.
Check the Oil
If your pump is oil lubricated, please check the oil regularly to ensure no water or product is present. If your sealing device is in good working order, regularly changing the oil will extend any pump’s life.
Water is dangerous because it can cause bearing and/or engine failure. Seals leak naturally, and a tiny bit of water is fine. When there is sufficient water in the oil, it becomes milky.
Some essential features may already be built into the design of your pump to aid in detecting water in your oil. The moisture sensor, for example, will trip if there is excessive water in the oil. Water in the oil is an early sign that the sealing has failed.
The first place to look is the sealing device on your specific pump. If you believe the moisture sensor gives you false alarms, consider adjusting the sensitivity level.
Check your Impeller Clearance
Checking your impeller clearance regularly will provide you with the best performance. For sufficient support, refer to your manual. When verifying authorization, look for excessive wear in the impeller and other wetted parts.
Wetted part wear can cause a clearance to rise, resulting in performance loss.
Wear can be induced by the abrasiveness of the product being pumped or by operating the pump outside of the pump’s intended curve.
Review your Slurry Pump Requirements
Is the slurry pump still expected to do what it was designed to do?
Sometimes systems and processes evolve, yet we continue to expect the same of our equipment without considering any modifications to the process that may have occurred over time.
Installing a pressure gauge and flow meter on the pump’s discharge line is an excellent option for troubleshooting. You can multiply the pressure reading by 2.31 to get a ballpark estimate. You can then take a flow reading to determine if your pump is running close to the pump curve.
Monitor your Pump Temperature
Temperature sensors are included with our submersible pumps for motor protection. Each handbook with the pump will explain how to connect and monitor the temperature sensors for best longevity.
If the motor overheats, the sensors will trip, and the pump will shut down until it cools. You run the danger of damaging your motor if the sensors are not connected.
The temperature of the bearings in our horizontal and cantilever pumps must be checked weekly while the pump is in operation. Check the temperature of the bearing housing closest to the bearing with a temperature gun.
While most pump bearings operate in the 140 to 170 F temperature range, I recommend never allowing temperatures to surpass 200 degrees F. Bearing temperatures might indicate excessive lubrication or the initial stages of bearing breakdown.
Monitor Pump Bearings
Making use of vibration equipment. This will alert you if the bearings begin to fail.
A certified and trained engineer/technician with experience in this field should undertake vibration analysis.
Proper vibration monitoring will provide the user with a wealth of helpful information that will boost the MTBF and improve the pump’s performance. For correct limitations, refer to the high-vibration guidelines for vertical, horizontal, and submersible pumps.
