Centrifugal Pump Preventative Maintenance Procedures & Schedules
July 16, 2019 Welcome
A centrifugal pump is a type of industrial pump that transfers fluids via rotational energy provided by one or multiple driven rotors known as impellers. Centrifugal pumps are used extensively in the power generation, oil and gas, and petrochemical industries to transfer low-viscosity fluids requiring high flow rates. This article will discuss some best practices for centrifugal pump maintenance.
Centrifugal Pump Efficiency
The pump efficiency of a centrifugal pump refers to the percentage of its input shaft to output shaft power. Centrifugal pump efficiencies range from 50% to 95% efficient depending on the flow rate, pressure, and pump configuration.
Mathematically, the centrifugal pump efficiency formula is:
Eff = Pw / Ps
(Where Eff is efficiency, Pw is input power, and Ps is output power).
Applications for Centrifugal Pumps
Centrifugal pumps are some of the most common pump types used for fluid transfer in midstream oil and gas, upstream oil and gas, power, refining, and chemical process industries. Centrifugal pumps may also form part of a larger pumping network alongside other pump types e.g., reciprocating pumps used in the secondary recovery phase of oil and gas production.
4 Common Failure Points that Require Pump Maintenance
Centrifugal pumps convert mechanical energy (required to rotate the impellers) to hydraulic energy (required to lift a column of fluid). If applied improperly, operated outside the normal operating range, or poorly maintained, pump components will break down over time, leading to reductions in pump efficiency and pump failures.
It is vital to schedule pump preventive maintenance to avoid an unexpected breakdown of the equipment. Below are common points of failure in centrifugal pumps and the pump maintenance procedures required:
1. Bearings and Points of Lubrication
Ensure the bearings, lubricant levels, and lubricant quality are maintained in proper condition. Follow the pump manufacturers guidelines for lubricant changes, lubricant type, and bearing operating temperature.
2. Pump Vibration
Excessive vibration in the bearings indicates an impending breakdown as it causes an unsustainable rise in temperature. If you notice excessive vibration in your centrifugal pump, you should have it checked out immediately. It could be a result of misalignment, cavitation, or normal wear.
3. Shaft Sealing
A sudden decrease in the efficiency of your centrifugal pump may be due to a broken shaft seal. Leaks from a broken seal reduce the pump pressure required to lift a column of fluid. Inspect the shaft seals for any physical signs of damage/leakage and replace the seal where necessary.
4. Impeller Clearance
An increase in the impeller to casing clearance can reduce the head pressure of the pump, negatively impacting pump discharge pressure. Routinely inspect impeller clearance and carry out clearance adjustments where necessary.
These standard maintenance procedures for centrifugal pumps can be carried out in accordance with the pump manufacturer’s instruction manual. Normal maintenance intervals are quarterly, biannually, or annually depending on the type of pump application.
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Preventive Maintenance Schedule for Pumps
Following the pump manufacture’s pump maintenance schedule will ensure that your centrifugal pumps are serviced when due to prevent costly downtime and expensive pump repairs. The following are some elements of an effective schedule:
- Determining maintenance frequency: How often do your centrifugal pumps require general maintenance or replacement of parts? What is a good time to schedule maintenance on the pumps to prevent downtime on operations? Asking these vital questions will help you to come up with a good strategy. However, be sure to create a maintenance schedule that is consistent with the manufacturer’s guidelines.
- Physical inspection: As often as required, carefully inspect mounting points, seals and packing, pump flanges, filters, and couplings for signs of damage, leaks, or accumulation of grease, dirt, or debris to ensure that the pumps function optimally. Plan to replace parts as soon as problems occur by procuring spares.
- Replacing the lubrication: Changing the lubricant in your centrifugal pump is essential to prevent damage of the bearings, but it must be scheduled according to the manufacturer’s instructions. You might, however, want to increase the frequency of replacement if you use the pumps more frequently than indicated.
- Inspecting the electric motor: The electric motor is the powerhouse of the centrifugal pump. Since it contains both mechanical and electronic components, it requires frequent maintenance to function correctly. Include physical inspection and testing of the motor in your pump maintenance schedule to check for loose electrical connections, faulty windings, blocked vents, overheating problems, etc.
Centrifugal Pump Maintenance Checklist
When carrying out routine maintenance for your centrifugal pumps, use this checklist to ensure that they are restored to optimal working conditions:
- Mechanical part inspection: Are all mechanical parts (seals and packing, pump flanges, filters, couplings, etc.) in good working condition? (Y/N)
- Electrical testing: Are all electrical/electronic parts (motors, switches, etc.) in good working condition? (Y/N)
- Lubricant: Is the lubricant in good condition? (Y/N) When last was it changed? ___
Trust IFS for All Your Centrifugal Pump Needs
Integrated Flow Solutions is a best-in-class process skid manufacturer of modular and custom solutions for the oilfield, petrochemical, and power generation industries. We offer a range of high-performance and ruggedly-dependable industrial pump packages to suit any type of fluid transfer operation.
For more information about IFS services or to speak with a professional, please contact us online today!