By Greg Washburn and Joshua Belisle · Edited by Dana Gardner
Published August 7, 2024 · Reviewed by Greg Washburn · August 31, 2026
Summary
What is a positive displacement vacuum pump for resin conveying?
A positive displacement vacuum pump uses a rotary lobe blower, belt driven by a three-phase motor, to create a deep vacuum for high-throughput or long-distance conveying of pellets, powders and regrind. It provides an operating vacuum of 12″ to 13″ Hg. Pumps typically ship fully assembled, either as stand-alone units or with several pumps mounted on a rack with soundproofing curtains.
Features to look for include a vacuum breaker that allows the pump to run-on past demand. This eliminates rapid start/stop cycles and reduces energy usage. A built-in cartridge filter with fines collection pan is suggested as is a discharge muffler to reduce noise level. Some manufacturers offer sound-deadening curtains to further reduce noise level.
PD Pumps can be used with line diameters of 1.5-4″” and provide an operating vacuum level of 12”-13″ Hg.
These pumps can be supplied as stand-alone pumps or multiple pumps may be mounted on a large rack with soundproofing curtains. It is fairly common for conveying systems to include one or more back-up pumps to provide coverage during maintenance times or for expansion.
Sizes generally run from 3Hp to 25 Hp.
Frequently Asked Questions
What features should I look for in a PD vacuum pump?
Look for a vacuum breaker that lets the pump run on past demand, which avoids rapid start/stop cycling and reduces energy use. A built-in cartridge filter with a fines collection pan and a discharge muffler to lower noise are also suggested. Some manufacturers add sound-deadening curtains for further noise reduction.
Should a conveying system have a backup vacuum pump?
It is fairly common for conveying systems to include one or more backup pumps. A spare pump provides coverage while a primary pump is down for maintenance and gives the system room for expansion. Multiple pumps can be mounted together on a large rack with soundproofing curtains, rather than installed as separate stand-alone units.
What line size and horsepower do PD conveying pumps come in?
PD pumps are used with material line diameters from 1.5″ to 4″ and are generally sized from 3 hp to 25 hp. That range, with an operating vacuum of 12″ to 13″ Hg, is what makes them suitable for high-throughput conveying and long-distance runs of pellets, powders and regrind.
About the Authors
Vice President of Operations, Novatec
Greg Washburn is Vice President of Operations at Novatec and has been with the company for more than three decades. He is involved in all phases of engineering design and product manufacturing, giving him a broad perspective on how resin drying and conveying equipment moves from engineering concept through production and into real-world processing environments. Greg holds a B.S. in Mechanical Engineering from the University of Maryland, Baltimore County (UMBC) and an MBA from Loyola University Maryland. His experience spans engineering, manufacturing and operations across Novatec’s material-handling technologies.
Technology Manager, Novatec
Joshua Belisle is Technology Manager at Novatec, where his work focuses on simulation and technology development for resin drying. He earned a B.S. in Mechanical Engineering with a minor in Engineering Business from the University of Virginia in 2023 and joined Novatec that same year. Joshua uses simulation tools to investigate previously difficult-to-measure aspects of the drying process, helping Novatec better understand airflow, heat transfer and other variables that influence resin-drying performance.
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