What Is a Positive Displacement Pump?
Positive displacement pumps (PDPs) are one of the most commonly used types of pumps. As suggested by the name, they rely on displacement mechanisms to move fluids. Unlike other types of pumps, these pumps offer the same flow capacities at a given speed regardless of inlet or discharge pressure. Additionally, they are more suitable for use in applications with demanding or specialized requirements, such as pumping liquids with high viscosities or suspended solids.
The following article provides an overview of positive displacement pumps, outlining the types available, key advantages, typical applications, and important selection considerations.
Types of Positive Displacement Pumps
Positive displacement pumps can be categorized into three main classifications:
- Rotary pumps. These pumps utilize rotating components to move fluid into and out of the pump chamber. Examples include gear pumps, lobe pumps, and screw pumps.
- Reciprocating pumps. These pumps employ a reciprocating mechanism to pull fluid into the cavity through an inlet valve, then expel it through the outlet. Examples include diaphragm, piston, and plunger pumps.
- Linear pumps. These pumps use a linear mechanism to displace fluids along a straight path. Examples include chain pumps and rope pumps.
Advantages of Positive Displacement Pumps
Compared to other types of pumps, positive displacement pumps offer a number of advantages. One of their primary benefits is their consistent flow rates. This quality makes them well-suited for pumping applications involving high-viscosity fluids, such as creams, oils, grease, slurries, and suspensions. They are also better able to accommodate high pressures and low flow rates.
Applications of Positive Displacement Pumps
Positive displacement pumps are used in a wide range of industries for a variety of applications and processes. Below we outline some of the typical uses of the types available.
- Rotary pumps. Gear pumps are used for pumping high-viscosity fluids in the chemical and petrochemical and food and beverage processing industries. Lobe pumps are employed in biotechnology, chemical, food and beverage, pharmaceutical, and other industries with high sanitation standards. Screw pumps are utilized for fuel transfer and injection, irrigation, and oil processing and production applications.
- Reciprocating pumps. Diaphragm pumps are used for metering and dispensing, cleaning, spraying, and water treatment operations. Piston and plunger pumps are employed for high-pressure washing and other applications involving low-viscosity fluids.
- Linear pumps. Chain and rope pumps are utilized in wells to pump water from the ground to the surface.
Selection Considerations for Positive Displacement Pumps
Positive displacement pumps are used throughout the industrial sector to force fluids into, out of, and between different processing and production equipment. When selecting a positive displacement pump, some of the key considerations to keep in mind to ensure it operates effectively and efficiently in the application environment include:
- Flow rate requirements
- Pressure requirements
- Power requirements
- Efficiency requirements
High-Quality Positive Displacement Pumps at Glauber Equipment
At Glauber Equipment, we carry a broad selection of positive displacement pumps from reputable manufacturers to suit the various pumping needs of our customers. Our pump offerings include:
- From Wilden: air-operated diaphragm pumps for the chemical, food, pharmaceutical, and wastewater industries
- From Enviro Gear: gear pumps for the asphalt, coating, and paint markets
- From Mouvex: eccentric disc pumps for the chemical, food, refined fuel, and other sanitary industries
- From PCM: progressive cavity pumps for the chemical, environmental, food, personal care, and pulp and paper industries
- From Almatec: air-operated, diaphragm solid block pumps for the ceramic, chemical, paper, and semiconductor markets
- From Tuthill: gear pumps for the agriculture, chemical, construction, and food and beverage industries
- From Neptune: chemical feed and injection-type pumps for the food and beverage, general, oil and gas, and wastewater industries
- From Verder/Alpha Laval: sanitary lobe pumps for the chemical, food and beverage, pharmaceutical, and wastewater markets
- From Vogelsang: rubber-lined lobe, shredder, macerator, and hopper-feed pumps for the biogas, chemical, food, pulp and paper, and wastewater markets
- From General Pump: high-pressure piston pumps for general industry use