PLANT

Keeping dust and fumes under control


November 5, 2008
by Steve Gahbauer

A Torit PowerCore baghouse dust collector.
Photo: Donaldson Torit

Almost every manufacturing process creates dust and debris. Steel and lumber mills are among the worst, while rock crushers, cement factories and co-generation plants burning peat create huge amounts of fine dust, not to mention machine and maintenance shops. Dust is also created by operating lathes, belt sanders, grinders, routers and saws.

And then there are the fumes, some toxic and some merely irritating, that are byproducts of a variety of processes, including soldering and welding. There are solvent vapours, lead fumes and acid mist, among others, that can cause respiratory problems.

Employees’ rights to work in a safe and healthy environment are enshrined in workplace rules and regulations, making control, extraction and collection systems mandatory. In the food, beverage and pharmaceutical industries, as well as in hospitals and medical facilities, clean-room environments are a must, requiring filter separators, vacuum pumps and a variety of dust extraction tools. In the maintenance area, floor sanders and welding operations require special attention.

Industry has responded to these needs by supplying a wide range of dry and wet type dust collection and fume extraction equipment that eliminates, or at least mitigates, contamination problems and deals with health and safety issues in the workplace. Some are general and some deal with special areas, such as metal processing, plasma and laser cutting, melting furnaces and pharmaceutical. All are tools for good housekeeping, which in industrial plants, leads to increased productivity and reduced breakdowns.

Collecting dust
For instance, Galaxy Machines in Toronto produces a series of dust containment systems with two high-performance 1.5 horsepower, brushless-vacuum motors, ultrafine filter-media traps, industrial grade nonmarking vacuum hoses and swivel hose cuffs, exhaust discharge hoses, and a filter volume of up to 68 litres. The lightweight systems collect dust in bags that are easy to empty.

Dust collectors can be baghouses, cyclones, central station systems or extraction booths. They can be ceiling-hung, cartridge-style, fixed or portable/mobile. The basic components of an efficient dust and fume collection system are hoods, ducts, fans, filters and a discharge stack or hose. Each plays an important role in removing dust, contaminated exhaust or toxic fumes. Extraction systems must offer easy access for cleaning and removal of captured elements, and they must comply with industrial guidelines and regulatory standards.

Many companies supply such systems, some general and some tailor-made. One of them is Eurovac Central Vacuum Systems in Concord, Ont.
Maintenance often involves machining, power tools, work that creates solvent vapours or toxic fumes and, of course, welding. There are special fume extraction systems that are designed to control welding fume exposure. Although mechanical ventilation is an effective method of fume control for most welding procedures, the better way is to employ a local exhaust source extraction system to control welding fumes, because it captures fumes near the arc or source. It can be mobile or stationary, single or multi-station, an exhaust and/or filtration system designed with adjustable extraction arms, nozzles or guns, in a fixed enclosure, or in a booth. This flexibility allows the most suitable adaptation to individual requirements.

Source extraction can be low vacuum/high volume for large, centralized exhaust systems, or high vacuum/low volume for close proximity (5 to 10 centimetre) positioning.