An industrial dust collector gathers nuisance and hazardous dusts and fumes from the air before they can settle on surfaces. Many facilities use dust collectors to keep process dust and fumes in check during manufacturing and processing operations to protect their workers and maintain compliance with major regulatory bodies like OSHA, NFPA and EPA. It is important to note that dust collectors differ from industrial vacuum systems, which are ideal for precision cleaning and material conveyance, while dust collectors are used for full-scale facility or process filtration.
There are several different types of dust collection systems that help to meet different requirements based on the facility’s size, type of process dust and application. There is no one “superior” type of dust collector; however, some may perform better than others in specific applications.
Some popular styles of dust collection systems include:
- Cartridge dust collector
- Wet scrubber
- Portable dust collector
Cartridge Dust Collector
Cartridge-style dust collectors are popular general-purpose factory air cleaning systems because they work well for many different applications. These collectors use filter cartridges full of pleated nonwoven fabric called media to capture dust and fumes from the airstream as it moves through. The filter media provides a large surface area on which to capture dust.
The filter media is made from a blend of polyester and cellulose and is sometimes coated with nanofibers in order to better release the dust when the cartridges are pulse cleaned. Media can also be made of spunbond fabric for increased durability against fibrous dusts or for dusts that require high-efficiency filtration.
How It Works
Cartridge-style collectors constantly suck in large volumes of air in order to filter out impurities that become airborne from production processes. The dust-laden air enters the collector through a baffled inlet and is forced through the filters where the dust becomes trapped in the filter media. The clean air continues through and out of the collector, where it is either vented out of the facility or recirculated back inside.
As the dust builds on the filter media over time, it begins to block the airstream, creating resistance. The resistance increases, causing the differential pressure within the system to rise. High differential pressure (referred to as “pressure drop”) causes the dust collector to work much harder to maintain the required airflow.
To relieve this pressure, the system pulse cleans the filters. It does this by sending a blast of compressed air through the center of the filter, which ejects the dust so it falls down into the hopper. Depending on the shape of the filter and the configuration of the media, some filters release more dust than others. For example, filters that use proprietary HemiPleat® pleating technology stay cleaner and last longer than standard filters.
HemiPleat technology uses synthetic beads to hold open the pleats and keep them evenly spaced, creating more surface area available for filtering inside each filter cartridge. This means more dust can be loaded onto each cartridge before it requires pulse cleaning. It also means the dust releases more readily when it is pulse cleaned, returning the differential pressure to normal.
Ideal Applications for Cartridge Dust Collectors
Cartridge dust collectors are ideal for these applications:
- Welding, laser or plasma cutting
- Grain, seed and feed processing
- Food manufacturing and processing
- Chemical processing
- Paper and metal packaging materials manufacturing
- Solid dose pharmaceutical product manufacturing
Baghouses (also called bag filter or fabric filter) operate in a similar way to a cartridge dust collector. The system removes dust particles from the air using a fan that forces the air through a long cylinder-shaped bag made from woven fabric. These systems are capable of handling high volumes of dust-laden air. They use a pulse-cleaning system similar to a cartridge dust collector to reverse-blast dust through deformation of the filter bags.
How It Works
Dust-laden air enters through the bottom of the dust collector then is filtered through the bags. The dust accumulates on the outside surface of the bags. At regular intervals, a burst of compressed air is shot through a parabolic nozzle that creates a shockwave, causing the particles to fall into the hopper. The filtered air is either recirculated or expelled outside, depending on the application and regulatory requirements.
Ideal Applications for Baghouses
Baghouses work best for applications involving:
- High CFM (airflow)
- Harsh environments like mining
- Applications that produce high volumes of dust
- High-temperature applications
- Sticky or abrasive materials
- Dust contaminated with oil and moisture
Wet scrubbers, also known as air scrubbers, use water or another liquid to remove dust particles from the air. Wet scrubbers are a popular choice for potentially explosive or flammable materials or operations where the slurry made up of liquid and collected dust particles can be reused.
How It Works
For sticky dusts, a compact multi-application-use wet scrubber like the Camfil Vortex is ideal. It passes air and dust through rough filtration then skims it over the surface of the water (scrubbing liquid). Some of the liquid flows through the vortex zone within the unit, which creates turbulence and atomizes the liquid into fine droplets. These droplets mix with the particle-laden air stream and are then removed by centrifugal force.
For more demanding applications with higher dust loading, Camfil’s Venturi is a more effective choice. It injects water, via a pump, into the inlet of the unit. Extremely high velocities are generated which create contact surfaces with the scrubbing liquid. The result is an effective mixing of the scrubbing liquid and the contaminated air stream. The particle-laden droplets are separated from the airstream by centrifugal force.
Maintaining a clean or recycled water supply is important with wet scrubbers. The concentration of dust particles in the scrubbing fluid must be kept below 5% in order to maintain operating efficiency. If the dust is combustible, the amount allowed to accumulate in the discharge vats is regulated by NFPA.
Ideal Applications for Wet Scrubbers
Wet scrubbers work best for applications involving:
- Wet or sticky dusts
- Humid air
- Combustible dust
Portable Dust Collector
Portable dust collectors, also known as unit dust collectors, are small and ideal for isolated jobs that produce dust. These jobs may or may not be located near your larger dust collection system. They can be strategically placed to capture dust from the source and can be used on their own or in tandem with a larger dust collection system to help extract any fugitive dust from the air.
How It Works
Portable dust collectors like Camfil’s Zephyr work similarly to larger cartridge dust collectors but on a smaller scale. The unit contains a long collection arm and hood that can be positioned to collect dust and fumes at the source. Dust-laden air travels through the arm and passes through a cartridge filter. When the filter becomes overloaded, a shot of compressed air can be directed through the filter and dust releases down into the tray to be removed. It is important to note that portable dust collectors are not suitable for explosive dusts and solvent fumes.
Ideal Applications for Portable Dust Collectors
Portable dust collectors work best for applications including:
- Isolated jobs not located near an inlet for your larger dust collection system
- Small shops that do not need a larger dust collection system
- Heavy dust load applications to work in tandem with a larger dust collection system
There are many available options to meet your dust, fume and mist collection needs. If you need help selecting the right option for your operations, our experts are here to help.