Slurry Pumps: The Ultimate Preventive Maintenance Guide

Angus EwartPumpsLeave a Comment

Are your slurry pumps in good condition?

I travel to customer sites on a weekly basis and I see a full range of good and bad when it comes to pump maintenance.

I decided to write a blog on the most common preventive maintenance tips concerning the Hevvy/Toyo line of pumps so it’s available even when I’m not.

This list is based off the most common errors that I see on a consistent basis.

How to ENSURE proper maintenance of your pumps? (In only 6 steps)

Step #1: Check the belts

When should you check the belt tension of the pump?

If your pump is belt driven please check the tension once quarterly at minimum. Belts that are too tight will cause damage to the light series motor bearing and once that bearing fails then the thrust bearing will start to fail in the pump. Belts ran too loose will cause poor performance and slippage causing damage to the sheaves.

*New belts should be checked 5-7 days after installation to ensure proper tension. I have a blog devoted to belt tensioning.

How to tell if the belts are loose?

I like to use a Gates tension tester. It is a simple tool and comes with instructions. An experienced ear can tell if the belts are too loose. They will be making a flapping sound. Belts that are too tight could cause the motor to be pulling high amps or bearing temperatures to increase before you start to notice bearing failure. We also recommend that you refer to TB Woods website and manuals for proper troubleshooting and maintenance on belt drives.

Step #2: Check the oil

When should you change the oil of your pump?

If your pump is on oil lubrication please check periodically to make sure no water or product is present in the oil. If your sealing device is ok, changing the oil on a regular interval will increase the lifetime of any pump.

Water is bad for your pump: How to know if there is water in the oil?

Water is bad as it will cause bearing and/or motor failure. Seals do leak by nature and a small amount of water is ok. A significant amount of water in the oil will cause the oil to be milky.

Some key features may be already incorporated into your pump’s design to help identify water in your oil. One such feature is the moisture sensor which will trip when there is excessive amounts of water in the oil. Water in the oil is an early indicator that sealing has been compromised.

The first place to check is the sealing device used on your particular pump. If you feel you are getting false alarms on the moisture sensor try adjusting the sensitivity setting.

Another thing to check is the setting distance from the end of the probe from the housing. If you’re unsure about this please contact our engineering team or myself for proper setting on the Hevvy/Toyo line.

Step #3: Check your impeller clearance

Best performance is achieved by checking your impeller clearance on occasion. Consult your manual for proper clearance. When checking clearance look for excessive wear in the impeller and other wetted parts.

Wear in the wetted parts can cause the clearance to increase causing a loss in performance.

Wear can be caused by the abrasiveness of the product being pumped or by running the pump off the designed curve for the pump.

Step #4: How to review pump requirements

Is the pump still being asked to do what it was built to do?

Sometimes systems and processes change but we continue to ask the same of our equipment without taking into consideration the changes to the process that may have been made throughout the years.

For trouble shooting it is a good idea to install a pressure gauge and flow meter on the discharge line of the pump. You can take the pressure reading and multiply it by 2.31 to give you a rough TDH. You can then take the TDH and a flow reading and see if your pump is running near BEP on the pump curve. If not, please contact the OEM.

Step #5: Monitor your pumps temperature

Temperature sensors are provided with our submersible pumps for protection of the motor. Each manual provided with the pump will outline how to hook up and monitor the temperature sensors for maximum lifetime.

Why should you care?

If the motor gets too hot the sensors will trip and the pump will shut down until the motor cools. If the sensors are not connected you are running the risk of burning up your motor.

If you ask for a warranty claim and these devices are not connected then your warranty is void.

When should you check your pump temperature?

Our horizontal and cantilever pumps need to have the temperature of the bearings checked weekly while the pump is in operation. Using a temperature gun check the bearing housing temp in the closest proximity to the bearing.

What temperature should it be?

While most pump bearings run in the 140 to 170 F range I suggest never allowing temperatures to exceed 200 degrees F maximum. Bearing temperatures can be a sign of too much lubrication or beginning stages of bearing failure.

Step #6: Monitor the pump bearings

Using some form of vibration equipment. This will give you an indication if bearings start to fail.

Vibration analysis should be performed by a qualified and trained engineer/ technician experienced with this type of work.

Proper vibration monitoring will give the user a lot of useful information which can increase the MTBF and improve performance of the pump. Refer to HI vibration guidelines on vertical, horizontal, and submersible pumps for proper limits. Consult Hevvy/Toyo engineering for more information.

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