The Ultimate Guide to Understanding Whether Positive Displacement Pumps Are Right for Your Application

There are some industrial applications where centrifugal pumps simply aren’t the best tool for the job. In most instances, this is because the industrial application calls for the use of medium-to-high-viscosity fluids or liquids that contain a high percentage of entrained gasses. Such applications are most commonly found in the oil and gas, concrete, chemical, and petrochemical industries.

This is where the design and engineering features of positive displacement (PD) pumps can help plant operators maximize productivity, efficiency, and dosing accuracy in contexts that require more viscous fluids or liquids that contain corrosive or environmentally hazardous chemical agents. 

Here, we’ll look at what plant operators need to know about the design and functionality of positive displacement pumps to help determine whether a specific application is right for the kind of flow and pressure rates positive displacement pumps bring to the table.

How do positive displacement pumps work?

There are two main types of positive displacement pumps: rotary or reciprocating. Rotary PD pumps use rotating cogs or gears to transfer or move fluids throughout the system. The rotating component creates a liquid seal with the pump casing and creates suction at the inlet. Fluid is then drawn into the pump, enclosed within the teeth of its rotating cogs or gears, and transferred to the discharge.

Reciprocating PD pumps move fluid via a repeated, back-and-forth motion using one of three primary mechanisms or systems: piston or diaphragm, pneumatic, or hose diaphragm. With piston-driven PD pumps, the piston creates a vacuum, opens an inlet valve, closes the outlet valve, and draws fluid into the piston chamber. Pneumatic PD pumps use pressurized air or gas to move fluid through the pump system, and a diaphragm PD pump uses a flexible membrane that moves fluid by expanding and compressing the diaphragm.

Positive displacement pumps help plant operators optimize their use of high-viscosity, potentially dangerous fluids in a variety of key ways, some of which include: 

• The ability to deliver fluids at a higher pressure compared to centrifugal pumps
• The capability to provide constant flow over varying discharge pressures
• Enhanced fluid transfer efficiency at any point on the Best Efficiency Point (BEP) curve, which is a mission-critical characteristic in optimizing your use of resources and creating consistent dosing and metering

how to know if positive displacement pumps are right for your application

When determining whether positive displacement pumps are ideal for your application, there are a couple of important elements to consider, specifically when it comes to how viscous the fluids are and the necessary level of flow and pressure to create a high-quality final product. 

For example, some applications that are ideal for positive displacement pumps include high-pressure cleaning, sewer jetting, chemical injection, crude oil transfer, dust suppression, mine dewatering, and reverse osmosis. Positive displacement pumps are also ideal for applications that require plant operators to process low-flow slurries that contain abrasive or non-abrasive soft or hard solids. 

The level of fluid viscosity used in your application is also important in identifying whether a positive displacement pump is right for your needs. 

For low-viscosity fluids, it’s important to ensure the fluid end materials are compatible with the fluid that's being used for dosing. In addition, plant operators must verify that the size of the pump is compatible with the flow and pressure rates necessary for adequate dosing. It’s also key to ensure that the duty suction conditions are within the pump’s acceptable NPSHR limits. 

In applications with high-viscosity fluids, positive displacement pumps must be equipped with compatible inlet and outlet valves to maximize flow and overall efficiency. What’s more, plant operators must also be mindful not to exceed the power rating of the pump’s drive end, as this can significantly hamper performance and result in increased maintenance intervals.

why partner with ipec for your positive displacement pumps

With more than 70 years of industrial pump experience and knowledge, IPEC has what it takes to help you design and create the ideal positive displacement pump to optimize your dosing and metering needs, regardless of the application. 

Our specialists can provide custom positive displacement pump solutions for a variety of industrial applications, including, chemical feed, polymer feed, high-pressure methanol injection, surface water treatment, and more. 

Plus, our longstanding partnership with industrial equipment leaders like Milton Roy and Yamada help us provide you with the packaged solutions, spare parts, and service necessary to keep you running 24/7, 365. What’s more, our expanded facility allows us to house a larger inventory of component parts and accessories, and it helps our technicians provide a wide range of maintenance, troubleshooting, and refurbishing services. 

Contact us to learn more about how positive displacement pumps from IPEC can help you optimize your productivity and efficiency.