Types of Industrial Dust Collectors
Industrial environments produce airborne dust that is hazardous, reduces visibility and creates a fire hazard. To keep employees safe and production flowing smoothly, facility managers employ industrial dust collection systems.
Whether portable or stationary, all dust collection systems have the same fundamental components. They feature a blower that recirculates contaminated air, a filter to remove dust and a receptacle to hold collected matter between cleaning cycles.
Baghouse industrial dust collectors use cylindrical fabric bags, which have a longer service lifecycle than cartridge filters, and are ideal for heavy load applications. They are commonly used to control air pollutants in grain milling operations, sifting, and elevators.
The filtration process takes place in a metal housing or vessel that is divided into two sides by a grate or tubesheet. Dirty air enters through an inlet on the dusty side and flows upward over the filter media. The filtered, clean air is then exhausted through the clean side of the unit.
Various models of baghouses are available for specific conditions. For example, the Donaldson RP baghouse has a SuperSepTM inlet that pre-separates air up to 97% before it hits the filters and focuses cleaning energy over the filter surface. It also has a PerfectPulseTM cleaning system that pulsates a burst of air into the filters to keep them clean.
Another model of baghouse, the Bagsonix series, has maintenance access inside industrial dust collector the dirty section of the unit and doesn’t require compressed air hook-up from an external source. It has a rotating arm that pushes a pulse of air through the filters to break loose dust and debris, and it has proximity sensors that ensure that each filter gets cleaned consistently. These models can be used with a variety of different types of filter bags.
Cartridge dust collectors utilize pleated nonwoven filter media, which allows for more surface area within a smaller footprint than baghouse or cyclone systems. They’re ideal for a variety of operations that produce fine to medium particulate, such as wood saws, composite mills, chemical and organic food and flavor industry compounds, welding smoke, plasma cutting, metal finishing and dry powder handling.
Like the baghouse system, cartridge industrial dust collection systems eliminate a wide range of abrasives and hazardous materials down to.3 microns. Their modular design allows them to fit in tight spaces without compromising maintenance accessibility. They’re also energy efficient and can return clean air back into the workspace reducing climate control costs.
As with the baghouse system, a cartridge dust collection system can be set up in either downflow or crossflow configurations. Downflow configurations place dirty and clean air plenums on opposite sides of the filters to reduce the upward velocity of dust particles, which can damage the filter.
Crossflow configurations have the dirty air inlet positioned below or at the side of the filters to aid gravity in moving dust particles toward the collection hopper. This helps improve filtration efficiency and eliminates the need for additional cleaning of the filters. Both types of systems use a pulse jet cleaning cycle, where short bursts of compressed air travel down the filters in the opposite direction of the flow of dirty air and knock accumulated dust off of the filter surface and into the collection hopper.
ESPs separate soot, ash, and dust particles from flue gases using static electricity. As the airborne dust passes over a series of wires and plates, it is charged with either positive or negative electric fields. The particles are then attracted to collecting electrodes that have the opposite charge and trapped. These collectors can achieve efficiencies of over 99%. ESPs are commonly used at coal-fired power plants and industrial factories that produce dust pollution such as metallurgical smelting.
Unlike a baghouse, an ESP is built to accommodate multiple layers of plates and wires. This allows it to industrial dust collector collect a much larger volume of particulate. It also provides higher efficiencies than baghouses, making it ideal for applications with high concentrations of particulate.
While ESPs have the ability to remove even the most difficult-to-remove dust, it’s important to keep in mind that they work best under normal resistivity conditions. Dust with a high resistivity makes it more difficult for the particle to transfer its electrical charge to the collection plate, which can lower a collector’s efficiency.
To avoid this, it’s essential to maintain a proper system operation. Among other things, this involves regularly rapping the system. This is done with rapper coils that send a shearing force to the plates and wires of the ESP. This causes the most resistant and sticky types of particulate to break up, allowing them to fall from the wires or collection plates and into the hopper.
Industrial cyclone dust collectors utilize centrifugal force to remove large or heavy chips from the air. They have a scroll type inlet, conical housing, internal vortex tube, collection “surge” hopper, and an optional scroll clean gas outlet. They can be used alone or as pre-cleaners for baghouse or cartridge collectors. They also help prevent larger dust particulate from damaging filters, which can significantly reduce the overall cost of a system.
They work by forcing air/dust into a circular motion and spinning it at thousands of rpm. The centrifugal force pins any heavier than air debris against the outside wall and gravity causes it to spiral down into the collection bin below. The resulting clean air is then drawn up and into a pleated filter stage for filtration and cleaning.
Cyclone dust collectors are ideal for applications where there may be a mix of large and fine particles. These systems can quickly separate large or heavy materials, and then direct the remaining gas stream to a larger baghouse or cartridge dust collector that uses filters to handle the fines. This can help eliminate unnecessary wear and tear on the filter in the baghouse, which is typically the most costly component of a system. It can also provide a significant cost saving by reducing the amount of fan horsepower needed for the system to operate.