Dust collection system
Encyclopedia
A dust collection system is an air quality improvement system used in industrial, commercial, and home production shops to improve breathable air quality and safety by removing particulate matter from the air and environment. Dust collection systems work on the basic formula of CAPTURE, CONVEY and COLLECT:
First the dust must be CAPTURED. This is done by employing devices such as capture hoods to catch the dust at the source of origin. Many times, the machine producing the dust will have an integral port to which a duct can be directly attached.
Second, the dust must be CONVEYED. This is done via a ducting system properly sized and manifolded to maintain a consistent minimum air velocity required to keep the dust in suspension for conveyance to the collection device. A mis-sized duct can lead to material settling in the duct system and clogging it.
Finally, the dust is COLLECTED. This is done via a variety of means, depending on the application and the dust being handled. It can be as simple as a basic pass-through filter, a cyclonic separator, or an impingement baffle. It can also be as complex as an electrostatic precipitator, a multistage baghouse, or a chemically treated wet scrubber or stripping tower.
where the waste material is drawn into an impeller
and deposited into a container (bag, barrel, canister, etc.). Air is recirculated into the shop after passing through an filter
to trap smaller particulate.
Larger systems utilize a dual-stage (or two-stage) system, which separates larger particles from fine dust using a pre-collection device (cyclone
, baffled canister, etc.) before drawing the air through the impeller. Air from these units can then be exhausted outdoors or filtered and recirculated back into the work space.
Dust collection systems are often part of a larger air quality management program that also includes large airborne particle filtration units mounted to the ceiling of shop spaces and mask systems to be worn by workers. Air filtration units are designed to process large volumes of air to remove fine particles (2 to 10 micrometre
s) suspended in the air. Masks are available in a variety of forms, from simple cotton face masks to elaborate respirator
s with tanked air — the need for which is determined by the environment in which the worker is operating.
In industry, round or rectangular ducts
are used to prevent build up of dust in processing equipment
.
, emphysema
, "flu
like" symptoms, and have more dangerous results decades after exposure such as cancer
. Wood dust also frequently contains chemicals and fungi
which can become airborne and lodged deeply in the lung
s, causing illness and damage.
First the dust must be CAPTURED. This is done by employing devices such as capture hoods to catch the dust at the source of origin. Many times, the machine producing the dust will have an integral port to which a duct can be directly attached.
Second, the dust must be CONVEYED. This is done via a ducting system properly sized and manifolded to maintain a consistent minimum air velocity required to keep the dust in suspension for conveyance to the collection device. A mis-sized duct can lead to material settling in the duct system and clogging it.
Finally, the dust is COLLECTED. This is done via a variety of means, depending on the application and the dust being handled. It can be as simple as a basic pass-through filter, a cyclonic separator, or an impingement baffle. It can also be as complex as an electrostatic precipitator, a multistage baghouse, or a chemically treated wet scrubber or stripping tower.
Types of systems
Smaller dust collection systems use a 'single-stage' vacuum unit to create suction and perform air filtrationFiltration
Filtration is commonly the mechanical or physical operation which is used for the separation of solids from fluids by interposing a medium through which only the fluid can pass...
where the waste material is drawn into an impeller
Impeller
An impeller is a rotor inside a tube or conduit used to increase the pressure and flow of a fluid.- Impellers in pumps :...
and deposited into a container (bag, barrel, canister, etc.). Air is recirculated into the shop after passing through an filter
Air filter
A particulate air filter is a device composed of fibrous materials which removes solid particulates such as dust, pollen, mold, and bacteria from the air. A chemical air filter consists of an absorbent or catalyst for the removal of airborne molecular contaminants such as volatile organic compounds...
to trap smaller particulate.
Larger systems utilize a dual-stage (or two-stage) system, which separates larger particles from fine dust using a pre-collection device (cyclone
Cyclonic separation
Cyclonic separation is a method of removing particulates from an air, gas or liquid stream, without the use of filters, through vortex separation. Rotational effects and gravity are used to separate mixtures of solids and fluids...
, baffled canister, etc.) before drawing the air through the impeller. Air from these units can then be exhausted outdoors or filtered and recirculated back into the work space.
Dust collection systems are often part of a larger air quality management program that also includes large airborne particle filtration units mounted to the ceiling of shop spaces and mask systems to be worn by workers. Air filtration units are designed to process large volumes of air to remove fine particles (2 to 10 micrometre
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
s) suspended in the air. Masks are available in a variety of forms, from simple cotton face masks to elaborate respirator
Respirator
A respirator is a device designed to protect the wearer from inhaling harmful dusts, fumes, vapors, or gases. Respirators come in a wide range of types and sizes used by the military, private industry, and the public...
s with tanked air — the need for which is determined by the environment in which the worker is operating.
In industry, round or rectangular ducts
Process Duct Work
Process duct work conveys large volumes of hot, dusty air from processing equipment to mills, baghouses to other process equipment. Process duct work may be round, or rectangular...
are used to prevent build up of dust in processing equipment
Process engineering
Process engineering focuses on the design, operation, control, and optimization of chemical, physical, and biological processes through the aid of systematic computer-based methods...
.
Dangers of neglect
Proper dust collection and air filtration is an important element in any work space. Repeated exposure to wood dust can cause chronic bronchitisBronchitis
Acute bronchitis is an inflammation of the large bronchi in the lungs that is usually caused by viruses or bacteria and may last several days or weeks. Characteristic symptoms include cough, sputum production, and shortness of breath and wheezing related to the obstruction of the inflamed airways...
, emphysema
Emphysema
Emphysema is a long-term, progressive disease of the lungs that primarily causes shortness of breath. In people with emphysema, the tissues necessary to support the physical shape and function of the lungs are destroyed. It is included in a group of diseases called chronic obstructive pulmonary...
, "flu
Influenza
Influenza, commonly referred to as the flu, is an infectious disease caused by RNA viruses of the family Orthomyxoviridae , that affects birds and mammals...
like" symptoms, and have more dangerous results decades after exposure such as cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
. Wood dust also frequently contains chemicals and fungi
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
which can become airborne and lodged deeply in the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s, causing illness and damage.