What is a Positive Displacement Pump (PDP)?

Positive displacement pumps, or PDPs, are devices that rely on forward pumping action to move fluid by trapping a fixed amount and transferring it through the discharge pipe. They are designed to prevent recirculation, providing a range of pump configurations to suit applications in industries such as oil and gas, food processing, pharmaceuticals, and wastewater treatment. Springer Parts offers decades of experience in supplying high-quality, direct replacement pump parts for positive displacement pumps to meet your needs.

Types of Positive Displacement Pumps and PDP Applications

Compared to other pump types that move fluid by velocity, positive displacement pumps trap a fixed amount of fluid and then mechanically displace it through the pump’s outlet, using components like pistons or diaphragms while ensuring a consistent flow regardless of pressure changes. Positive displacement pumps are commonly used for:

• Viscous fluids

• Precise dosing

• High-pressure applications

• Low-flow, high-head conditions

• Handling shear-sensitive fluids

There are two main types of positive displacement pumps: reciprocating and rotary.

About Reciprocating Pumps

Reciprocating pumps, like piston, plunger, and diaphragm pumps, are used in applications that require high pressure and precise flow control. Handling viscous fluids and operating in low-flow, high-pressure environments, reciprocating pumps can be used in:

• Oil and gas pipelines

• Hydraulic systems

• Chemical dosing

• Water jet cutting

• High-pressure cleaning

Understanding Rotary Pumps

Rotary pumps, which include gear, lobe, screw, vane, and peristaltic pumps, deliver steady, low-pulsation flow to handle viscous fluids at moderate pressures. They are designed for a smooth, continuous flow in applications such as:

• Lubrication systems

• Fuel transfer

• Hydraulic systems

• Chemical processing

• Food and beverage production

How Does a Positive Displacement Pump Work?

While all positive displacement pumps use mechanical force to transfer fluids, different pump types utilize various methods to achieve their operational processes.

How Rotary Pumps Work

Rotary-type pumps, specifically lobe and gear pumps, use rotating components to trap fluid, either between gear teeth and the casing or lobes and the casing, to move the fluid. Similarly, screw pumps create sealed cavities between the rotating shaft and intermeshing screw components, allowing them to move fluid axially to the output.

How Reciprocating Pumps Work

Alternatively, reciprocating pumps prioritize transfer methods using suction, with the exception of peristaltic pumps, which use rollers and a flexible tube to push fluid to the outlet. Diaphragm pumps utilize a flexible diaphragm that expands and contracts to draw in fluids and then expel them. Piston and plunger pumps operate similarly to diaphragm pumps, but use a component within a cylinder to complete their process.

Benefits of Positive Displacement Pumps

The advantages of choosing positive displacement pumps for fluid transfer and handling applications include:

• Accurate and predictable flow

• Handles a wide range of viscosities

• Self-priming capabilities

• Reduced wear and tear

• Features a non-slip design

Discover High-Quality Pump Replacement Solutions from Springer Parts

Springer Parts is a trusted supplier of aftermarket pump solutions for a range of applications. With state-of-the-art pumps and pump replacement parts, our products are competitively priced, typically 20-40% cheaper than OEMs, and include specifications and warranties that meet or exceed OEM standards. Contact us to discuss pump solutions for your operations or request a quote to get started.