Jun 14, 2023

Preventing Cold

Rick Kreczmer, RoboVent | Nov 17, 2022

Do things seem a little dustier in your facility these days? Every fall and winter, we see an uptick in maintenance calls for industrial dust collection systems. Is the cold weather to blame? Winter weather can cause problems for electronics and pulsing systems in outdoor dust collectors. But the most common dust collector repair calls we see each fall have a much simpler solution. Here’s how you can prepare your dust collection system for a problem-free fall and winter.

Every fall, we get calls from facilities that tell us that their dust collection system is suddenly not keeping up. They may notice more haze in the air in the facility, or it may be more unpleasant to breathe. Do cooling temperatures cause the dust collection system to fail? Not really. What does tend to happen in the fall is much simpler: facilities close up doors and windows to hold in heat. Open doors and windows create natural ventilation that dilutes any contaminants in the air. When the bay doors close, there is a sudden reduction in this natural ventilation.

If you’re noticing more haze after closing up for the season, it’s probably not because anything has changed with your dust collection system. You’re simply now noticing what was true all along: your dust collection system is not effectively filtering air at the rate needed to meet your indoor air quality goals. Most of the time, this simply means you’re overdue for standard maintenance. Occasionally, it may mean that it’s time to look at your dust collection system design.

A complete dust collector preventive maintenance (PM) service is advisable to make sure the system is in good working order. The first thing to check: when was the last time your filters were changed? Old, loaded filters cause your dust collector to work harder to overcome excessive pressure drop across the filters. Older filters may also develop pinhole tears or leaks that allow dust to escape past the filters. If the filters are near (or past) the end of their lifespan, fall is a good time to change them—especially if your dust collector is located outside in a colder climate. Changing dust collector filters is not something you want to be doing in the snow. Make sure that filters are installed correctly and there aren’t any leaks around the filter gaskets.

While you’re at it, check the collection bin or tray. Are you changing the bin regularly as it gets full? In the absence of a rotary airlock, dust from an over-full bin or tray can back up into the hopper. This situation can damage your dust collector and, if your dust is combustible, raise the risk of a dangerous combustion event inside the collector. A bin sensor can be installed to tell you when dust levels in the bin have reached their maximum. To keep your system in good working order, change the bin or tray as soon as it becomes full, which may be as often as daily or weekly, depending on your processes and the size of your collection bin.

A comprehensive PM service will also include visual inspection and cleaning of both the interior and exterior of the dust collector. The inspection should include:

If you are still seeing problems, it may be that your dust collection system is not sized properly to keep up with current production processes, or you need a different style of hood or enclosure for efficient capture of particulate from production processes. If you have added or changed processes in the last few months, natural ventilation may have been masking a bigger problem with your system. A dust collection system engineer can help you get to the bottom of it.

If your dust collector is located outside, there are a couple of problems you might see in the winter months as temperatures drop below freezing. The most common problems our repair teams see are:

Cartridge dust collectors, along with many baghouse dust collectors, rely on a compressed air pulsing system to pulse excess dust off the filters. Usually, the air compressor is located inside and is pulsing warm compressed air into the hoses and valves inside the air compressor. When the collector is located outside, the temperature differential can cause excess moisture to fall out of the compressed air stream like dew. This moisture can accumulate in the air regulator or pulsing valve system and turn to ice, causing the pulsing system to fail. We usually see problems first in the pressure regulator.

What to do: If you are seeing ice crystals in the pulsing system air regulator during winter months, it may be time to upgrade your air drying system. Compressed air dryers are installed after the compressor and before the distribution hoses or ductwork to remove excess moisture from compressed air. Some dryers work by refrigeration, but they may not get air dry enough to prevent condensation in very low temperatures. Consider a desiccant dryer to further lower the dew point of compressed air coming into the pulsing system.

You can also insulate the portion of the compressed air system that is located outside, including the pulsing system air lines. Insulation will prevent air temperatures from dropping below the dew point that allows moisture to fall out.

In very cold weather, we sometimes see the programmable logic controllers (PLCs) in the dust collector control system start to fail. The LCDs in touch screens can also fail at low temperatures. Every electronic component has an optimal operating temperature range. Most are designed to work in temperatures of 0°C – 60°C (32°F – 140°F). Those designed for extended temperature applications may work down to temperatures of -30°C (-22°F). Below the rated operating temperature for the electronics, you may experience problems with the dust collector control system, such as:

We most frequently see problems with dust collector control systems after a weekend or period of extended shutdown when system components are allowed to get very cold.

What to do: The control system for an outdoor dust collector can often be located inside to prevent these problems. If the control system is outside, insulation or a heater can be installed to prevent the system from getting too cold. In the short term, if your dust collector will not start after a long weekend, you can wait until it warms up naturally or try warming up the system with warm air or a heated cloth. Be sure to use gentle warming methods to bring your system up to temperature slowly to prevent further damage to electronics. And never introduce an open flame, spark or high heat source near the dust collector.

For trouble-free dust collection through the winter months, a thorough PM service in the fall is your first line of defense. Follow all manufacturer’s recommendations for dust collector PM and consider contracting with an expert service provider if you do not have the expertise on your maintenance staff. If your dust collector is located outside and you are anticipating below-freezing temperatures this winter, consider installing insulation or heating for your dust collector before colder temperatures set in. Taking the time to ensure that your system is in good working order now will prevent unexpected shutdowns and production delays this winter.

Rick Kreczmer, President, RoboVentRick Kreczmer is an industrial air filtration industry veteran with more than 24 years of experience in sales and executive management. As President of RoboVent, he has led the company through new product innovation and market initiatives to lay the foundation for continued growth and profitability in an evolving manufacturing environment.

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Dust Collector Failures in Fall and WinterWhat To Do: The Fall Tune-UpProtecting Your Outdoor Dust Collector in Freezing TemperaturesCompressed Air Pulsing SystemWhat to do: Control SystemsWhat to do: The Bottom Line: Getting Ready for WinterAbout the Author Rick Kreczmer, President, RoboVent