Guide to Selecting a Centrifugal Pump
As we see from this Wiki, selecting the appropriate centrifugal pump for an application involves several key considerations.
And it is by no mean as simple choice.
At SPS Pumps, our expert team is there to help in every step of the process.
Just call us at +32 2 657 23 53 or send an email to info@sps-pumps.com
We will find the best solution for you application.
Below is a structured approach to guide you through this selection process.
1. Identify the Liquid to be Pumped
The first step is to determine the type of liquid that the pump will handle:
- Distribution Water
Typically requires clean water pumps with materials resistant to corrosion. Is the application related to groundwater extraction, water transfer, circulation pump etc… - Wastewater
Requires pumps capable of handling solids and varying viscosities, often with features to prevent clogging. What is the size of the maximal solid part. What is the liquid solid content in percent, etc… - Other Liquids
Depending on the chemical properties, temperature, and viscosity and whether the pump is related to a specific process, i.e. food, chemicals, etc… specialised materials and designs may be required. A proper investigation probably is required.
2. Define the Purpose of the Pump
Understanding the primary purpose of the pump helps narrow down the suitable types:
- Circulating Pumps
Used for maintaining the flow of water in a closed system, such as heating or cooling systems. - Transfer Pumps
Designed for moving liquids from one location to another, often used in industrial processes. - Pressure Boosters
Used to increase water pressure in systems, essential for high-rise buildings and irrigation systems.
3. Determine the System Requirements
Evaluate the specific requirements of your system:
- Flow Rate (Q): The volume of liquid to be moved per unit time, typically measured in cubic meters per hour (m³/h).
- Head (H): The height the pump needs to lift the liquid, measured in meters, which includes both static and dynamic components.
4. Analyse Pump Performance Curves
Examine the pump performance curves provided in the data sheet:
- Head vs. Flow Curve
Ensure the duty point, where the system curve intersects the pump curve, falls within the high-efficiency area of the pump. - Efficiency Curve
Select a pump that operates close to its Best Efficiency Point to maximise performance and energy efficiency. - Power Consumption
Identify the required P2 power to ensure the selected motor can deliver this power without overloading.
5. Consider Net Positive Suction Head (NPSH)
Ensure the NPSH available (NPSHa) in your system exceeds the NPSH required (NPSHr) by the pump:
- NPSHa: The absolute pressure at the suction side provided by the system.
- NPSHr: The minimum pressure required by the pump to avoid cavitation.
Adequate NPSH prevents cavitation, which can cause significant damage to the pump.
6. Material and Construction
Select the appropriate materials based on the liquid properties and operating conditions:
- Corrosion Resistance: For aggressive or corrosive liquids.
- Durability: For handling solids or abrasive materials in wastewater.
7. Motor Selection
Choosing the right motor is integral to the overall performance and efficiency of the pump. The motor must be capable of delivering the required P2 power as indicated by the pump’s power consumption curve.
It is essential to select a motor with sufficient power to avoid overloading while maintaining energy efficiency. Additionally, consider the motor’s speed, enclosure type, and compatibility with the pump to ensure seamless integration and reliable operation.
Proper motor selection not only enhances pump performance but also contributes to energy savings and reduced maintenance costs.
8. Evaluating the Need for an Inverter for Variable Speed Operation
Assessing whether an inverter for variable speed operation is necessary is a key part of motor selection. Variable speed drives (VSDs) allow for the adjustment of the motor speed to match the system’s demand, ensuring stable output pressure and significantly enhancing energy efficiency. Implementing a Variable Speed Drive can lead to reduced energy consumption, lower operational costs, and improved system control, making it an advantageous choice for many applications, particularly where load conditions fluctuate.
9. Additional Considerations
- Pump Size and Installation Space
Ensure the selected pump fits within the available space and installation constraints. - Maintenance and Reliability
Consider the ease of maintenance and the reliability of the pump for continuous operation.
SPS Pumps is at your Disposal
SPS Pumps is the ideal partner for industry. We offer unrivalled technical support and in-depth knowledge of centrifugal pumps, as well as other types of pump.
Our expertise guarantees you reliable and efficient solutions tailored to your needs.
We also have a very wide range of spare parts in stock.
With SPS Pumps, you have a trusted partner committed to optimising your fluid handling systems.
Call us at +32 2 657 23 53 or send us an e-mail at info@sps-pumps.com.
