Finding the Right Pneumatic Conveying System
Updated: Jan 22, 2021
Pneumatic Conveying Systems deliver raw materials (usually powders and/or pellets) to extruders, mixers, coolers and other vessels and devices in the manufacturing process. The air used to convey those materials can either be vacuum or positive pressures, usually determined by the distances covered and the level of friability of the material being conveyed.
Pneumatic Conveyors utilize industrial blowers that are engineered and constructed to run 24×7 for trouble-free amounts of time if (and only if) they are sized correctly.
Blowers sometimes fall victim to improperly applied and overly cost-conscience selection. An industrial blower is designed to operate within an engineered range that provides the proper level of performance. When a pneumatic conveying system is driven beyond the correct RPM range, you will be forced to deal with an increase in heat, it will work harder producing pressures it was never intended to produce and be forcing materials at a higher rate through a pipe that is now too small. Using a down-sized blower that is being over-driven beyond it’s operating range results in frequent breakdowns.
Clear Signs of Trouble
Product degradation and Angel Hair can be caused by overly high/extreme velocities, elevated temperatures and an undersized line.
Line Clogs, Slugging and Plugging can be caused by low velocity and pressures that are too high or too low.
Premature wearing-out of belts and sequencing valves can be caused by running an undersized unit which results in spinning the blower too fast and/or utilizing an undersized vacuum receiver with overly frequent fill cycles.
Degrading of Capacity and Delivery can be caused by clogged filters, improper venting of the receiving vessel(s) and/or insufficient air volume.
What to Look Out For?
Heat is bad. Heat is created by running the Blowers faster than the operating level it was designed for. Overdrive them and they will generate more life shortening, wear increasing heat.
Wasteful Energy usage. Blowers that are run beyond their maximum recommended output will burn more electricity than Blowers that are run within their operating range. It’s a law of physics and like most laws-not negotiable. Energy charges are higher during peak hours. With the importance of Green Technology, do you want the public to know you have an energy conscience and are running a “Green” operation? This is difficult to do with undersized blowers and overworked motors inefficiently burning up excess electricity, wouldn’t you agree?
Noise. More decibels mean more operator complaints, unflattering Customer plant tours, possible OSHA workplace violations and greater image problems in general. Up sizing a Blower just to the next larger size provides a larger flow band volume at lower pressures and reduces heat production, decreases noise and lowers energy consumption.
Clogged Filters. These create more pressure, which creates more energy use, more heat, less throughput, etc. It is important to monitor pressure ranges in your filtration vessels when you (a) first install new filters, (2) eight hours later (or after the flowing particulates have helped increase the filtration ability of a brand new filter) and (3) at excessive pressure levels over the design range (usually between 8-12 psi on the magnehelic gauge).
Right-Sizing. Ultimately, every pneumatic system is about proper balance – the balance between pressure and velocity, the balance between material volume being moved and the volume of the air required to move it. If the blowers, line sizes and receivers are undersized, there are very few performance increasing options (short of replacement). Receivers that are too small have to discharge more frequently to meet demand which results in more cycles, greater starts and stops and this creates more wear on the blowers, motors, belts, pulleys, etc.
Sizing the System Requires Experience
There are proven ways to pneumatically convey powders and pellets reliably without trauma and breakdowns. Our Power Pressure Units and Vacuum Pressure Units are proven in the PVC, CPVC, Wood Fiber, Friction Products, Food and Pharmaceutical Industries. We provide Project Management, Design and Engineering, Systems Integration, New Equipment, Components and Parts, Rail Car Unloading and Plug & Play Systems. Contact us and O.A. Newton will be happy to discuss how we can arrive at the most cost-effective solution for your unique operation. We manufacture our components here in Bridgeville, Delaware and can provide the correct custom solution for your unique plant and production needs.