Fume and Smoke Collectors Information

Fume and smoke collectors reduce the amount of fumes and smoke in the workplace atmosphere. Fume collectors are commonly used alongside welding equipment and other devices that generate plumes of smoke, fumes or debris during operation. They are designed either as source collectors to capture material directly or as ambient collectors to treat air as it circulates through an environment.

Fume and smoke collectorsSmoke and fumes are sub-micron particulates created by processes such as welding, rubber and plastic processing, and high-speed machining with coolants, tempering, and quenching.

Types

Media Filter Collectors
Media filter fume and smoke collectors, use high efficiency particulate air (HEPA)-type filters to remove industrial fumes and smoke. In operation, air containing fumes or smoke is drawn into the cartridge media by a fan or blower. It is then forced through the filter where the fume and smoke particles are trapped or filtered out by the media material. Nanofiber filter media is most common for welding and metal fumes.

The efficiency of media filter collectors varies depending on the filter type used. Pressure drops for these systems are usually higher than other types of fume and smoke collectors, so power requirements are often higher. Current cartridge fume and smoke collectors are typically modular and include options for pre-filters, HEPA filters, activated carbon, as well as high-powered fans that can reach as high as 18,000 cubic feet per minute (cfm).

Electrostatic Collector
Electrostatic precipitator (ESP) fume and smoke collectors use high voltage to charge and gather the smaller mist particles and droplets. Fume or smoke streams enter the collector and are passed through a region containing one or more high-voltage electrodes. The electrode(s) apply a charge to the particles in the stream, causing them to stick to oppositely charged plates or surfaces in the system. The collection surfaces are routinely cleaned either manually or automatically.

ESP fume collectors typically provide the most efficient particle collection of sub-micron smoke and fumes at constant flow and low pressure drop. They also eliminate the need to use and replace expensive HEPA filters. However, ESP collectors may cost more initially than other types. Also, manually cleaned ESP collectors are not suitable for heavy fumes with larger particles because the limited surface area would require excessive cleaning and maintenance.
 
Well engineered electrostatic fume collectors can collect particles as small as 0.003 microns in diameter, and are the most commonly used systems for filtering oil smoke in industrial applications.
  

Categories

Particulate collectors can also be categorized based on what types of media they can use to treat their mode of operation.
 
Media Types
Mist and fume collector units are often best suited for certain types of media with different particle sizes.
  • Smoke has particles ranging from 0.07 to 1.2 microns.
  • Welding fumes contain particles 0.01 micrometer (mm) to 1 mm.
  • Tobacco smoke particles are 0.01 mm to 0.05 mm.
 
Collection Method
Fume and smoke eliminator units are designed for ambient operation or source collection.
  • Ambient units are designed to continuously filter airborne particles as air circulates through an environment. They are used in applications where there is no specific source of the smoke or fumes or where the use of ducts and source-capture arms is limited.
  • Source collectors are designed with ducts and arms to capture and filter air at the source. They can be either stationary or portable units.

Specifications

Performance specifications are the ratings assigned by a manufacturer that describe a collector's performance. These are the specifications most important for an industrial buyer to consider when selecting a suitable smoke and fume collector for their application.
  • Maximum air flow or gas flow rate is the maximum amount of air or gas flow that the collector can accept, measured in cfm. This effectively defines the cleaning capacity of the smoke and fume collector.
  • Minimum particle size filter indicates the minimum diameter of smoke particles that the collector is capable of capturing, measured in micrometers. This rating defines the collector's range of capability.
  • Efficiency, collection efficiency, or capture rate defines the percentage of fume or smoke pollutants removed by the collector. Certain types of filters have rated efficiencies for particulate collection.
  • HEPA filters are replaceable extended-media dry-type filters in a rigid frame having a minimum particle collective efficiency of 99.97% for 0.3 micron particles or larger, and a maximum clean filter pressure drop of 2.54 cm (1 in) water gauge when tested at rated air flow capacity.
  • Ultra low penetration air (ULPA) filters are extended media dry filters in a rigid frame that have a minimum particle collection efficiency of 99.999% for 0.12 micron particles or larger.
  • American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) filters are designed up to efficiencies of 95% for 0.5 micron particles or larger.
  • Activated carbon and specialty blended filters are used to treat gas streams with specific types of pollutants.
Fume and smoke collectors
Additional Specifications
Fume collectors are rated using a number of additional specifications that may be important to consider.
  • Connections — The electrical connections for the collector unit.
  • Motor/Power — The specifications of the collector's motor, or the power requirements for the collector, measured in horsepower (hp). 
  • Size — The dimensions (length, width, depth) of the collector unit, given in feet or inches.
  • Sound level — The noise produced by the collector during operation, measured in A-weighted decibels (dBA).
  • Storage capacity — The amount of storage space for captured pollutants. This determines how frequently the filter or collector must be cleaned or replaced.
  • Weight — The weight of the collector unit, given in pounds (lbs).

Related Information

Engineering360—How to Select Air Pollution Control Products for Asphalt Roofing Manufacturing

References  

 
 

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