Key Categories of Pumps: Positive Displacement Pumps & Centrifugal Pumps

Keith Fink
Author : Keith Fink
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    What is a Centrifugal Pump?

    A centrifugal pump is a type of pump that uses rotational energy, typically supplied by an engine or electric motor, to move fluids through a piping system. The primary component of a centrifugal pump is the impeller, which rotates and transfers kinetic energy to the fluid, causing it to move outward from the center of rotation and increase in pressure. Centrifugal pumps are commonly used in industries such as water supply, chemical processing, and HVAC systems.

    Types of Centrifugal Pumps
    Sub-Type Description Performance
    Axial Flow Pump Moves fluid along the axis of the impeller, suitable for high flow, low head applications. High flow rate, low pressure head. Often used in irrigation, flood control, and circulation systems.
    Radial Flow Pump Moves fluid perpendicular to the impeller's axis, typically for high head, low flow applications. High pressure head, low flow rate. Commonly used in water supply and high-pressure cleaning systems.
    Mixed Flow Pump Combines features of axial and radial flow pumps, designed for medium head and medium flow rates. Moderate flow rate and pressure head. Suitable for industrial processes and large-scale water transfers.

    What is a Positive Displacement Pump?

    Positive displacement pumps operate by trapping a fixed amount of fluid and then forcing (displacing) that trapped volume into the discharge pipe. Unlike centrifugal pumps, these pumps deliver a constant flow regardless of pressure. They are highly efficient for handling viscous fluids and are widely used in applications such as chemical injection, oil drilling, and hydraulic systems.

    Sub-Type Description Example
    Reciprocating Pump Uses pistons, plungers, or diaphragms to move fluid in a linear motion Bladder Diaphragm Peristaltic Piston/plunger
    Rotary Pump Moves fluid using rotating mechanisms like gears or screws Gear Screw Progressing cavity Rotary lobe Rotary vane

    Comparing Centrifugal and Positive Displacement Pumps

    Aspect Centrifugal Pump Positive Displacement Pump
    Flow Rate Varies with pressure; higher pressure reduces flow rate. Constant flow rate regardless of pressure changes
    Viscosity Handling Less efficient with high-viscosity fluids Highly efficient with high-viscosity fluids.
    Pressure Capability Generally lower pressure; suitable for low to medium pressure applications. Capable of high pressure; ideal for high-pressure applications
    Efficiency High efficiency with low-viscosity fluids and steady-state operations High efficiency with varying viscosities and across a wide range of pressures
    Maintenance Typically lower maintenance requirements Generally higher maintenance due to more moving parts.


    Choosing the right pump for your application is crucial for efficiency and performance. While centrifugal pumps are ideal for low-viscosity fluids and low to medium pressure systems, positive displacement pumps excel in handling high-viscosity fluids and high-pressure applications. Understanding their respective advantages can help MEP engineers make informed decisions for optimal system design.

    At NY Engineers, our team has an impressive 80% first-time design approval rate, ensuring that your systems are not only efficient but also compliant with industry standards. Whether you're dealing with water supply, chemical processing, or specialized industrial applications, our expertise ensures that you get the most suitable pump for your needs.

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    Tags : centrifugal pump pump types positive displacement pump pumps

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