By Greg Washburn and Joshua Belisle · Edited by Dana Gardner
Published August 6, 2024 · Reviewed by Greg Washburn · August 14, 2026
Summary
What are the alternatives to a central resin conveying system?
The main alternatives to central vacuum conveying are moving resin by bucket and ladder, self-contained vacuum loaders, screw augers, compressed air venturi loaders, and pressure blowers with an air lock. Each trades lower cost or simplicity for labor, energy, floor space, fines or rejects. A central vacuum system conveys from multiple sources to multiple destinations with less labor and cleaner housekeeping.
Let’s examine the alternatives to an automated resin conveying system and consider what can be accomplished with the installation of a central system.
Invariably, if you are a plastics processor, you have to move resin from one place to another….sometimes from multiple sources to multiple destinations.
Here are the basic material sources and their possible destinations…
Resin may arrive at your plant in:
- Bags
- Boxes
- Gaylords
- Super sacks
- Bulk truck
- Rail car
You may have to move that material to:
- Silos
- Surge bins
- Drying hoppers
- Blender hoppers
- Machine throat
Additionally you may want to transfer regrind from granulators back into the production stream.
There are multiple ways to move the resin.
Move resin manually with a bucket and ladder
Pros:
- Buckets and ladders are inexpensive
Cons:
- Very labor intensive so costs are high
- Climbing ladder increases chance of employee injury
- Resin spills on the floor, further increases costs and chance of injury
- Hoppers may run low on material resulting in short residence times and poorly dried material
- Molding machines are frequently starved for material
- High percentage of rejected parts due to resin contamination and poor drying
Use Vacuum Loaders to move material from gaylords to destination
Pros:
- Self contained loaders are relatively inexpensive and easy to set up
Cons:
- High energy consumption
- High labor costs to replace brushes and motors
- Gaylords remain on production floor
- Space required to allow forklifts to deliver Gaylords
Use a screw auger device to twist and grind the material up to its destination
- Better than the bucket brigade
- May be used for starve feed applications
Cons:
- May produce undesirable fines and debris on the floor resulting in injuries
- Bulky drive system takes up a lot of floor space
- Labor intensive due to constant monitoring
- Results in high % of rejects when flow is interrupted
Blow resin with a compressed air venturi loader.
- Inexpensive to purchase.
- Low material delivery rates
- Compressed air required
- Blows fines into the environment creating housekeeping problems
Blow resin with pressure blower and air lock device.
- Very high delivery rates.
Cons:
- High equipment investment
- Blows fines into the environment creating housekeeping problems
- Requires a cyclone to separate air from material
Use central vacuum conveying system to convey resin from one or more locations to one or more destinations
Pros:
- Moderately priced
- Delivery rates to match any requirement
- Maximizes machine up-time
- Improves uniformity of product quality
- Maximizes use of floor space by minimizing congestion around the machines
- Allows material validation and verification
- No fines blown into the environment
- Greatly improved housekeeping – reducing injuries
- Minimizes material waste
- Expandable with several system configurations
- Easily integrated with silos, blenders, dryers, surge bins, etc.
- Can be integrated with plant-wide monitoring and control systems
- Minimizes human intervention in the process to ensure lower labor costs
Cons:
- Personnel may need to be re-trained to operate larger systems.
Frequently Asked Questions
What are the drawbacks of self-contained vacuum loaders?
Self-contained loaders are relatively inexpensive and easy to set up, but they come with high energy consumption and labor costs for replacing brushes and motors. Gaylords also stay on the production floor, and space has to be left open for forklifts to deliver them to each machine.
Why not blow resin with compressed air or a pressure blower?
Compressed air venturi loaders are inexpensive to buy but deliver material slowly, require compressed air, and blow fines into the plant. Pressure blowers with an air lock deliver very high rates but need a high equipment investment, also blow fines into the environment, and require a cyclone to separate air from material.
What are the benefits of a central vacuum conveying system?
A central vacuum system conveys resin from one or more sources to one or more destinations at rates matched to the requirement. It supports machine uptime, more uniform product quality, less congestion around machines, material verification, cleaner housekeeping and less waste. The main trade-off is retraining personnel to run a larger system.
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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