Page 50 - OHS, October 2021

IH: INDOOR AIR QUALITY
and preserve product quality by ensuring all formulation weights made it into the process.
ThThe paint producer was handling approximately 3,000 pounds of powder per batch through a combination of super sacs and 50-pound bags. The dust collector captured dust created by manual dumping of materials into a mixer. Typically, material captured from dust discharge will go into a drum or container. There are several fine powders included in a paint’s formulation. One of the most challenging is Titanium Dioxide which has a reputation of sticking, bridging, plugging, clogging and ratholing. Without an optimized system, the dust collection system could experience a backup.
While a mechanical conveyor could have been used to deliver the captured material into the mixer at a lower upfront cost than a vacuum conveyor, the smaller footprint and minimal maintenance requirements offset any savings due to existing equipment that created obstacles to maintenance and installation of a mechanical conveyor. The combination of the dust collector and the vacuum conveying system produced a zero-waste system and eliminated the need for operators to wear respirators.
Engineering out a respirable dust hazard with a closed processing system is especially important when dealing with metal powders that are toxic to the human body. Additive manufacturing (AM) is quickly becoming a focus within the occupational health and safety world due to its combustible, respirable and skin contact hazards (and the usual musculoskeletal injuries associated with heavy materials).
Recently, an OEM of hybrid additive manufacturing technology focused on automating the messy, daunting and potentially hazardous sieving process to improve the work environment at its own facility and to be able to offer that same technology as ancillary equipment to its clients. Metal recovery systems are fairly simple systems in terms of design, but because metal powders used in AM are fine, heavy, dusty and sometimes reactive, special knowledge of material characteristics is required for a safe, effective vacuum conveying system.
What made this particular application unique was the customer’s desire to
weigh small amounts of the recovered powder back into its original containers for inventory control purposes and ergonomics, and that required a little more engineering. With this system the customer achieved his/her safety goals and experienced greater than anticipated labor cost savings. What used to take an hour and a half, and require two operators, now only takes four minutes and one operator.
In addition, the use of respirators is no longer necessary for the task, although operators can still choose to wear one.
The inherent nature of fully enclosed vacuum conveying systems improves indoor air quality and routinely increases efficiency and the bottom line.
Doan Pendleton is the President of VAC-U- MAX.
46 Occupational Health & Safety | OCTOBER 2021
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