Comparing Positive Displacement Pumps to Centrifugal Pumps: Which Is Right for Your Business?

When it comes to selecting the right pump for your business, understanding the differences between positive displacement pumps and centrifugal pumps is imperative. Both types of pumps indeed serve essential functions in various industries. However, they operate differently and are suited to distinct applications. 

In this guide, we will take the time to compare positive displacement pumps to centrifugal pumps. Our goal is to help you determine which one is the right choice for your business.

What Are Positive Displacement Pumps?

Positive displacement pumps have been designed to move fluid by trapping a fixed amount of it and then displacing that trapped volume into a discharge pipe. They have a reputation for effectively delivering a consistent flow rate regardless of changes in pressure, making them ideal for applications where precise fluid control is necessary.

Types of Positive Displacement Pumps

Positive displacement pumps come in several types, including:

• Reciprocating Pumps: These pumps use a piston or diaphragm to move fluid.
• Rotary Pumps: These include gear pumps, screw pumps, and vane pumps, all of which use rotating mechanisms to move fluid.
• Peristaltic Pumps: Often used in medical and chemical applications, these pumps use a squeezing action to move fluids through a flexible tube.

Positive Displacement Pump Applications

Due to their ability to maintain a constant flow rate, positive displacement pumps are commonly used in industries where precision is critical, such as:

• Chemical Processing: They are used for dosing chemicals and handling high-viscosity fluids.
• Oil and Gas: These pumps are ideal for transferring crude oil and other viscous liquids.
• Food and Beverage: In these industries, positive displacement pumps are used for moving sensitive or shear-sensitive products like creams, syrups, and oils.

What Are Centrifugal Pumps?

Centrifugal pumps work by converting rotational kinetic energy, typically from a motor, into hydrodynamic energy to move fluid. Unlike positive displacement pumps, centrifugal pumps have a flow rate that varies with pressure changes.

Types of Centrifugal Pumps

Centrifugal pumps are also diverse, with various types designed for specific needs:

• Single-Stage Centrifugal Pumps: These pumps have one impeller and are typically used for low-pressure applications.
• Multi-Stage Centrifugal Pumps: Featuring multiple impellers, these pumps are used when higher pressures are required.
• Submersible Pumps: Designed to be submerged in the fluid they are pumping, these are commonly used in wastewater and drainage applications.

Centrifugal Pump Applications

Centrifugal pumps are widely used in industries where large volumes of fluid need to be moved quickly and efficiently, such as:

• Water Supply and Treatment: Centrifugal pumps are commonly used for moving water in municipal water systems.
• HVAC Systems: These pumps circulate water and other fluids in heating and cooling systems.
• Agriculture: In irrigation systems, centrifugal pumps are often used to distribute water over large areas.

Positive Displacement Pumps vs. Centrifugal Pumps

Understanding the differences between positive displacement and centrifugal pumps is vital for selecting the right pump for your business needs.

Flow Rate and Pressure

One of the most significant differences between the two pump types is how they handle flow rate and pressure. Positive displacement pumps maintain a consistent flow rate regardless of changes in pressure. This characteristic makes them ideal for applications where precision and consistency are paramount.  

On the other hand, centrifugal pumps have a flow rate that varies with pressure. As the pressure increases, the flow rate decreases. This makes centrifugal pumps better suited for applications where high flow rates are needed, and pressure fluctuations are less of a concern.

Efficiency and Energy Consumption

When comparing efficiency, positive displacement pumps tend to be more efficient in handling viscous fluids and maintaining a steady flow. However, they may consume more energy when dealing with fluids that require high pressure to move.

Centrifugal pumps, in contrast, are generally more energy-efficient for low-viscosity fluids and applications where high flow rates are required. Their design allows them to handle large volumes of fluid with relatively low energy consumption, making them a cost-effective option for many businesses.

Maintenance and Durability

Maintenance and durability are also crucial factors to consider. Positive displacement pumps generally have more moving parts, which may lead to higher maintenance needs over time. However, their robust design allows them to handle abrasive and corrosive materials effectively, making them durable in harsh environments.

One of the perks of centrifugal pumps is that with fewer moving parts they tend to require less maintenance. However, they may be less durable when handling viscous or abrasive fluids, as these can cause wear on the impeller and other components.

Which Pump Is Right for Your Business?

Choosing between a positive displacement pump and a centrifugal pump depends on several factors. You’ll want to take into consideration the nature of the fluid being pumped, the required flow rate, and the specific application.

• Choose a Positive Displacement Pump if:
  • Your application requires precise, consistent flow rates.
  • You are dealing with high-viscosity fluids or need to move abrasive or corrosive materials.
  • Energy efficiency is less of a concern than maintaining a steady flow under varying pressures.
• Choose a Centrifugal Pump if:
  • You need to move large volumes of low-viscosity fluids quickly and efficiently.
  • Your application involves fluctuating pressure and doesn’t require a constant flow rate.
  • You are looking for a cost-effective solution with lower maintenance needs.

Comparing Positive Displacement Pumps vs Centrifugal Pumps

Below you’ll find a list of the advantages vs the disadvantages of both pump types. 

Positive Displacement Pumps

Advantages:

• Consistent flow rate regardless of pressure changes
• Ideal for high-viscosity fluids and precise applications
• Capable of handling abrasive or corrosive materials
• Effective for dosing and metering applications

Disadvantages:

• Higher energy consumption, especially with high-pressure fluids
• More complex with more moving parts, leading to potentially higher maintenance needs
• Generally less efficient for low-viscosity fluids

Centrifugal Pumps

Advantages:

• High flow rates, ideal for moving large volumes of fluid
• More energy-efficient for low-viscosity fluids
• Simpler design with fewer moving parts, leading to lower maintenance requirements
• Cost-effective for general fluid transfer applications

Disadvantages:

• Flow rate varies with pressure, less suitable for precision applications
• Less effective with high-viscosity fluids or when consistent flow is required
• Can experience wear when handling abrasive or corrosive fluids

Choosing the Right Pump for Your Business

Selecting the right pump for your business is crucial, whether you’re considering a positive displacement pump or a centrifugal pump. Each type has its advantages and is better suited for specific applications, so making an informed decision is essential. At C&B Equipment, we specialize in helping businesses like yours find the perfect pump solution.

As a trusted provider of industrial equipment, including pumps, blowers, air compressors, and more, we offer customized packages and comprehensive support services to ensure your operations run smoothly. Serving clients across Kansas, Missouri, Arkansas, and the Texas Panhandle, we are here to assist with all your industrial equipment needs.

Contact us today to discover how we can help you choose the right pump for your business and keep your operations at peak efficiency!