View A Video on Dust Collectors - A Quick IntroductionDust Collectors
The particles released during manufacturing processes are hazardous to both worker and equipment health, quickly leading to a number of problems if particles are not captured by
dust collection equipment and filtered from facility air.
Dust collection addresses this problem by drawing contaminated air through a filter or separator, trapping harmful particles and releasing cleaner air into the atmosphere or back onto the work floor.
Industrial dust collectors come in various types and sizes, including fabric filter
baghouses and
jet dust collectors,
cyclone dust collectors,
wet dust collectors,
cartridge collectors,
small dust collectors,
portable dust collectors,
downdraft tables and
dust collecting systems complete with multiple suction hoods and overhanging ductwork. Dust collection is a vital process for coal handling, cement fabrication, metal fabrication, mining, chemical processing, woodworking, pharmaceutical, recycling and agricultural industries, among many others. Industry-specific state OSHA regulations require companies to hold their facilities to strict standards for indoor air quality, and the EPA and other regulatory bodies put limits on emissions of dust, smoke and fumes into the atmosphere. Dust collectors play a major role in helping companies meet these requirements and improve both indoor and outdoor environments by capturing a high percentage of the particles emitted by industrial processes.
Baghouses are the most common dust collector design and are often the most cost-effective. Baghouses draw contaminated air in through ducts to a hopper-shaped baghouse containing fabric filters made of cotton, synthetics or glass-fiber. The air is pulled through the fabric bags by a vacuum-creating fan, leaving behind dust, smoke and particles; clean air exits through the fan at the outlet, while dust particles either cling to the filter or settle into an airlock at the bottom of the hopper, which is routinely emptied. As a cake of dust accumulates on the filter, it actually increases the effectiveness of the filter for trapping tiny particles. After a point, however, the filter cake can become too thick and begins to stress the system, so occasional cleaning is necessary to ensure sufficient airflow through the filters. For this reason, baghouse dust collectors are sometimes equipped with vibrators that shake filters free of dust. Similarly, jet dust collectors are baghouses which use jets of compressed air to blow the dust-caked fabric bag filters free of excess dirt.
Some dust collectors, such as cyclone dust collectors, settling chambers and baffle chambers, do not rely on filters but instead rely primarily on gravity and inertia, and thus are known as inertial separators. Cyclone dust collectors use centrifugal, or cyclonic, air movement within a hopper-shaped chamber to separate particles from the air; the particles, being heavier than air molecules, are thrown against the outer wall of the hopper and fall to the bottom, where they are collected. Multi-cyclone dust collectors have a single main inlet on one side and a single outlet on the other side, but incorporate many cyclone cylinders inside the chamber that run concurrently; single-cyclone dust collectors have only one cyclone. Settling chambers reduce the speed of an air stream, which allows the heavier particles to settle out more quickly. Baffle chambers set up a barrier that forces the air to change directions suddenly, so that the inertia of the heavier particles does not allow them to remain suspended in the air stream and they fall to the bottom of the chamber. Cyclone dust collectors, settling chambers and baffle chambers are most effective at removing the coarser dust particles from contaminated air, and so are well suited as pre-cleaners for baghouses and other dust collectors that are more efficient at removing fine particulate.
Large facilities usually incorporate baghouses, jet dust collectors and inertial separators into sizeable dust collecting systems, with overhead ductwork and capture arms with suction hoods that hang over the workspaces where dust is formed. In such applications, the dust collector apparatus is often located outside of the facility, connected to the interior by ducts. Facilities may also use smaller, self-contained ‘unit' dust collectors or portable dust collectors, either in addition to or in place of larger systems. Generally using fabric filters or cyclonic motion to collect particles, portable dust collectors can be easily moved from place to place to provide localized dust collection. Similarly, downdraft tables are work tables with built-in dust collection equipment for filtering the dust from processes performed over the table, such as welding and wood sawing. Some special downdraft tables and unit dust collectors, known as wet scrubbers or wet dust collectors, use liquids (usually water) to intercept dust particles from the stream of gas. Others, known as electrostatic precipitators, give particles a negative charge and then attract them out of the air stream by means of a positively charged electrode. Wet scrubber and electrostatic precipitator technology is also employed in some air pollution control equipment, performing similar functions on molecular levels by removing soot, smog and fine chemical pollution from the air of industrial facilities. As the dust collecting industry advances, smaller, cleaner and more efficient separating and filtering equipment is being developed to better meet the needs of industry while increasing worker safety and protecting environmental health.
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Image Provided by Ultra Flow Dust Collectors |
Dust Collector Types
- Baffle chambers cause dusty air to change direction suddenly so that gravity and inertia carry the heavier dust particles downward, out of the air stream and into a collection area.
- are dust collection filters typically constructed from glass fibers or fabric.
- Cartridge collectors are compact filters that have a much greater surface area than bags, which increases the airflow, lowers resistance and reduces frequency of cleaning.
- rely on centrifugal force to remove dust from air.
- filter dust particles by spinning the air around in its tank. The motion pins the particles against the walls; they gradually move downward and eventually end up in the collection bin.
- are systems that vent from the top and pull fumes and dust up past the worker's face.
- or workstations have perforated tabletops and back walls and draw dust and fumes away from the worker's breathing zone.
- filter air and remove dust before releasing clean air back into the environment.
- is the process of filtering air and removing dust.
- Dust collection equipment encompasses a wide variety of devices and systems designed to minimize air particle contamination in commercial and industrial spaces.
- collect dust through ionization. As dust-filled gases move through the system's positively-charged, grounded electrodes called collection plates, discharge electrodes give the dust particles a negative charge, which causes the ionized dust particles to be attracted to and caught by the collection plates.
- , or baghouses, contain filters called fabric bags, which efficiently trap fine particles of dust, while allowing gases to move through the collector.
- Industrial dust collectors minimize the presence of various pollutants in order to maintain a high standard of clean air in workshops, plants and manufacturing facilities.
- separate dust particles from gas by changing the direction of gas streams as the streams flow through the collector.
- use a jet-based cleaning cycle.
- can be moved from place to place.
- use compressed air to force a burst of air down through the fabric bag and expand it violently. When the bag reaches its limit, the dust separates from the bag, and the escaping air carries the dust away from the fabric surface.
- Settling chambers slow the movement of dusty air to allow for the heavier particles to settle out.
- collect the product in filter bags as the silo is being filled with material. The bags are then shaken to return the valuable product to the silo.
- Small dust collectors solve air pollution problems when limited space for filtration is available.
- are small dust collecting systems that contain a fan and either a fabric collector or a cyclone.
- pull a continuous stream of air from the environment, removing airborne dust particles.
- Wet dust collectors soak dust-filled gas streams with water and separate the wet dust particles through varying degrees of pressure drops.
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Dust Collector Terms
- The amount of process gas or air entering the fabric collector (baghouse) divided by the square feet of cloth in the fabric collector.
- Form of pneumoconiosis caused by the inhalation of asbestos minerals into the lung, resulting in lung scarring, breathing problems and various forms of cancer.
- Also called "leakthrough," it is the ability of particles of dust or fumes to migrate through the fabric bag.
- Also referred to as "filter cake," it is the dust buildup occurring on the surface of the filter medium during filtration that often aids in the filtration process.
- International professional designation available through training and testing by the Association of Energy Engineers (AEE).
- Family of chemicals used as refrigerants, being tightly regulated and phased out of production due to stratospheric ozone depletion potential. Examples: R-11, R-12, R-113, R-114, R-115.
- The act of dipping the filter medium into a solution in order to lubricate the fibers to reduce self-abrasion.
- Electrodes in an electrostatic precipitator that attract and collect negatively charged particles of dust.
- The amount of dust that the gas or air contains. Concentration is expressed in grains per cubic foot or pounds per hour.
- Electrodes in an electrostatic precipitator that negatively charge dust particles.
- Conductors or parts of a semiconductor that create an electrical connection with nonmetals or control the movement of electrons.
- Filter in a fabric collector consisting of woven or felt material such as cotton.
- Toxic particles that penetrate the lungs, causing lung dysfunction and scar tissue formation.
- The porous barrier used in the filtration process to separate the particles from the fluid stream.
- The fabric collector equipment from inlet flange to outlet flange.
- Cloth wear in a fabric bag caused by excessive bending.
- A hood-shaped inlet designed to collect contaminated air and direct it into the exhaust dust system of a baghouse.
- In dust collecting systems, the area in which the collected dust is stored.
- Also called "nuisance dust," it consists of particles of which quartz and other silicates compose less than one percent.
- Medium- to large-sized dust particles that do not reach the lower respiratory tract but remain in the upper respiratory system, nose and throat.
- A device that sucks up fine particles from fluids like oils and even dry smoke using a three-phase motor. The inner drum rotates and draws the mist particles to the center of the drum where they are forced together and eventually pass through perforations in the drum and back into the machine's coolant tank, while clean air blows past the motor and back into the outside environment.
- Centrifugal separators containing several parallel cyclones that separate dust particles according to texture.
- Common high-voltage electrostatic precipitator consisting of flat collection plates along which discharge electrodes lie.
- Respiratory ailment caused by excessive inhalation of metallic or mineral dust matter. Pneumoconiosis also includes diseases such as silicosis and asbestosis.
- Part of electrostatic precipitator that transfers dust from the collection plates to the hopper.
- Small dust particles inhaled into the lower regions of the lungs that are responsible for different types of pneumoconiosis.
- Incurable, potentially deadly type of pneumoconiosis caused by the inhalation of silica dust particles, resulting in lung diseases such as emphysema. Silicosis progresses even after contact with silicates has ceased.
- More or less consistent wear on the dirty side of the fabric bag cloth.
- Consists of all dust particles, whether respirable or inhalable.
- High-voltage electrostatic precipitators consisting of cylindrical collection plates that rotate around the discharge electrodes.
- Part of an electrostatic precipitator that transfers dust from the collection plates to the hopper. |
