Designing a dust collection system requires a thoughtful approach that involves studying all the necessary features or capabilities and how they will work together to provide the desired outcomes. Here are some essential things to remember before and during the dust collection system design process.
1. Industry-Related Requirements
An excellent starting point is to consider some of the challenges or necessities associated with your particular industry and why the associated work requires adequate dust collection. That approach should uncover some design specifications that will help the dust collector work as expected.
For example, the pharmaceutical industry typically attaches dust collectors to tablet presses. The presses don’t generate a lot of particles. However, proper dust collection design is essential because the dust could contain active pharmaceutical ingredients that put workers at risk or cross-contaminate nearby equipment. The dust collectors designed for tablet presses are often cartridge types because they work effectively with small footprints.
Dust collection in the food industry comes with specific challenges, too. One concern is people in the sector often work with so-called nuisance dust from ingredients such as sugar and flour. They aren’t toxic but can cause respiratory irritation if inhaled in quantities employees may encounter. One option is to enclose those processes and use source-capture mechanisms to minimize dust.
Food industry dust can also have characteristics that warrant specific design considerations. If the dust arises from milling, grinding, or seed-hulling, the collector may need an abrasive-resistant inlet. Some food industry dust is also hygroscopic or moisture-absorbing. It may cake onto equipment--especially in humid environments--but using a coated filter in the dust collector discourages that buildup.
These are just a couple of the many examples of how people must study industry needs when assessing how best to design dust collectors. That way, there’s the highest likelihood that the result fits a company’s current and future requirements and does not introduce complications.
2. Placement and Frequency of Use
Getting great results with the design of a dust collection system also involves thinking about where and how often the facility generates particles. Designing a continuous-duty model is a great choice if factory processes create dust throughout the workday in large portions of the facility.
On the other hand, having individual dust collectors strategically placed at certain workstations is likely the better option if only certain parts of the facility have high levels of particulate matter. Having a clear understanding of where high levels of dust occur will also guide decisions about how often the company will run the dust collector and how people must dispose of the gathered dust.
For example, how much dust does the facility produce per day, week, or a similarly easy-to-measure metric? Will the company use it daily for extended periods or just occasionally and in association with particular processes? Answering those questions will help people design dust collectors with adequate volume.
Planning the location of dump stations is also helpful during dust collector design discussions. When people at a company design several dust collectors for individual workstations, the most convenient option is probably to let people empty the collectors as close as possible to their work areas or at an easily accessible, dedicated point in the facility.
Thinking about where to put the dust collector and how often the company will use it makes it easier to design a system that uses the appropriate filters, too. Baghouse fiberglass filters are common choices in dust collectors for industries associated with high acid levels. Nylon filters resist alkali-related effects but cannot tolerate high-heat environments. Polyester filters work well in environments with excessive carbon dust but can’t withstand high humidity.
3. Reinforcements to Mitigate Explosions
Combustible dust is one of the ever-present risks in many factory environments. Particles ranging from wood to flour can explode if exposed to ignition sources. Even some materials not normally classified as combustible can catch on fire or explode if they’re present in certain sizes and concentrations.
Thus, a dust collection system must have design features to minimize the risks and effects of explosions. One factor to consider is whether the system has adequate reinforcements to withstand the flowing pressure associated with the blast. Otherwise, as the pressure rises, the system will eventually fail, causing a secondary event that sends hot gas, flames, and shrapnel into the environment.
One study of more than 200 dust collectors around the world showed almost all vented systems needed better reinforcement to tolerate the pressure. The coverage of this matter pointed out that most dust collectors are square or round, but those are two of the worst shapes when designing a dust collector not to cause a secondary explosion. In contrast, cylindrical-shaped collectors better tolerate explosion-related pressures. The considerations don’t end there, though.
Even cylindrical dust collectors commonly have components that are not strong enough to handle explosion pressures. Those include doors, hinges, latches, and nozzles. Moreover, many cylindrical dust collectors have flat roofs. In such cases, reinforcement or replacement are the main options and the former is less expensive. Any decisions to reinforce the dust collector must also involve examining the device’s ribs and the panels between the ribs.
Guidelines within National Fire Protection Association (NFPA) 68 (2013) clarify how to make pressure calculations for potential explosions when assessing reinforcements. Any changes to increase strength must make it so the anticipated pressure is less than two-thirds of 0.2% of the material’s yield stress.
Many pieces of modern equipment are part of the industrial internet of things (IIoT), which means they can connect to the internet. Company decision-makers often invest in IIoT products that offer real-time data collection. It is then possible to continuously monitor the workplace, even from off-site locations.
Suppose designers decide to make the dust collection system IIoT-ready. In that case, they should consider things like how often the product will provide updates, what it will tell users, and how people will get such notifications.
One wise and practical course of action is to study the offerings of commercially available connected dust collectors and use that information for inspiration. Such options are relatively limited currently. However, given how many industries must collect dust to meet regulatory, safety and other requirements, opportunities for growth exist.
One available product collects information about a system’s differential air pressure. A drop in that metric indicates the need for an immediate filter change. However, if the differential air pressure rises, filter damage could be the reason.
The IIoT can also help facility managers assess relative airflow. Inadequate airflow associated with a filter could indicate the dust collector cannot remove particles from the environment efficiently enough. If that’s the case, the dust can build up and pose a fire hazard.
Dust Collection System Design Requires a Careful Approach
An effective dust collection system is an essential part of keeping an industrial facility clean, safe and compliant with relevant regulations. Considering the factors discussed above will help people get off to a good start, whether designing a system from scratch or redesigning an existing dust collector.
Emily Newton is editor-in-chief, Revolutionized Magazine.