While centrifugal pumps are robust, special consideration must be taken during the pump startup to ensure their long life. In this guide, we share with you a step-by-step guide on starting centrifugal pumps the right way.
Centrifugal pumps are one of the most commonly used pumps. They are used in a wide range of industries – power plants, paper manufacturing, food processing, chemical industries, wastewater plants, and more.
Centrifugal pumps convert the electrical energy from a motor or turbine into kinetic energy. The generated kinetic energy is converted into pressure energy to move the fluid being pumped. This transformation of electric power into kinetic energy occurs at two main parts of the pump:
At the impeller
At the volute (also known as the diffuser)
The impeller is the rotating part of the pump that converts electric energy into kinetic energy. The volute then converts the kinetic energy to pressure energy.
Centrifugal Pump Startup Checklist
*Make sure that your pump operator performs all the tasks listed here before starting the pump. You can even print out this checklist and laminate and stick it near the pump for future reference.
Open the suction valve.
Open cooling/recirculation lines.
Depending on system conditions, partially open or fully close the discharge valve.
Start the driver.
Slowly open the discharge valve until the desired flow is reached.
Check the pressure gauge to ensure that the desired discharge pressure is reached. If the correct discharge pressure is not reached, do the following steps:
Stop the driver.
Prime the pump again and restart the driver.
Check the pump conditions during operation.
Watch out for bearing temperature, noise, and vibration.
If any of these conditions exceed normal levels, then shut the pump quickly and rectify the issue.
Repeat steps 6 and 7 until the pump operates at the desired levels.
Safety Precautions to Follow while Operating a Centrifugal Pump
To avoid any accidents during pump usage and causing damage to the pump, ensure that you follow these safety precautions.
#1: Always Read and Follow the Instruction Manual
All pumps come with a detailed instruction manual issued by the pump manufacturer. Make sure that all plant operators read and understand the manual thoroughly. Refer to the manual before making any changes to pump components.
For example, each centrifugal pump has a specific clearance limit (the distance between the impeller and the wear plate) mentioned in the manual. Going below or above this clearance limit will reduce the pump’s efficiency, causing pump components to wear out quickly.
#2: Watch out for Overheating
Overheating not only damages the critical pump components but could also lead to burns and injuries for pump operators. To ensure that the centrifugal pump doesn’t overheat, leave the suction and discharge lines open during pump operation.
If you notice overheating, quickly stop pump operation and allow it cool. Make sure to vent at the drain plug cautiously before restarting the pump. Wait for some time till the overheated pump cools down before attempting to remove the cover plate or gauge the plug.
#3: Replace Worn-Out Components
To avoid catastrophic accidents, make sure that you replace any worn-out components quickly. For example, if the bearing is worn out, it causes the shaft to wobble, leading to overheating. Watch out for signs of scratches and rapid wear on seals. Worn-out components can lead to excessive noise, overheating, and rocking. So, make sure that you replace worn-out internal parts quickly.
#4: Look out for Air Leaks & Blockages on the Suction Line
Worn-out components can cause air leaks, which, in turn, will lead to a drop in the static lift of the pump. Check if the suction line is air-tight by using a vacuum gauge. Blockages on the suction line can lead to low discharge pressure while building a high vacuum inside the pump.
#5: Always Perform Routine Maintenance
Regular pump maintenance should be done at least every six months or more frequently, depending on the pump’s operating conditions. During care, ensure that accumulated debris is cleared out. No debris obstructs the strainers on the discharge and suction lines.
#6: Do a Pump Shut-off Test
This test ensures that the internal components of the pump are free from wear and tear. Here are the steps involved:
Start the pump.
Wait until it reaches maximum flow.
Close the discharge valve and record the readings at the suction and discharge gauges.
If the pump is operating at the right conditions, then the readings should show zero flow.
#7: Check the Condition of Discharge Lines
Old discharge lines are prone to rust, leading to flow reduction and friction losses. So, check all discharge lines components, including – check valves, shock control devices, and release devices.
#8: Don’t Be Complacent
This cannot be stressed enough. It doesn’t matter if it’s your first time operating the pump or your hundredth. You cannot afford to be complacent. Always approach the pump with caution during operation. Ensure that all the pump shields and guards are in place to avoid accidents.
#9: While installing the pump, Consider Accessibility
A centrifugal pump must be placed close to the liquid. Ensure that there are at least three feet of clearance between the pump and other surrounding equipment.
#10: Use the Pump only for Designated Use
To avoid accidents, always use the pump only for its intended usage. Do not pump corrosive or flammable liquids like acid if the pump is designed for pumping water. Similarly, ensure that only experienced personnel operate the pump. Do not wear loose clothing or accessories while operating the machinery. Make it a point to don appropriate safety gear while using the pump.
Centrifugal pumps reach high velocity and pressures during operation. Hence, you must follow the correct startup and safety procedures to ensure maximum efficiency and avoid accidents. For any further help on operating your industrial centrifugal pumps, get in touch with our pump experts here at Sintech, India’s leading centrifugal pump manufacturer and exporter.Safe operating!