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Smoke and dust extraction

Engineering technologies such as the thermal cutting of metals (flame, plasma or laser), welding, grinding or blasting produce fumes and dust or gas emissions which are a burden on the working environment in production areas and pose a health risk to the human body if exposed for a long time. According to the Air Act No. 201/2012 Coll., such technologies are considered sources of pollution and are subject to supervision by state environmental authorities.

It follows that every owner (operator) of such technologies wishes to effectively reduce smoke and emissions in the working area to the lowest possible level. This is achieved by extracting the exhaust fumes and then thoroughly filtering the polluted air.

The extraction of polluted air can generally be carried out in two ways:
1. Spatial extraction
Extraction from the total volume of the workshop/hall area by a filter tower or filtration unit connected to the HVAC system (Push - Pull or other system). The device is suitable e.g. for welding plants with a high flexibility of welding sites that are not used in parallel.
2. Local extraction
Extraction directly at the source of the fumes by fume exhaust hoods, extraction arms or an extraction workbench. Bottom suction of material workbenches is the most efficient and virtually the only effective solution for the thermal cutting of metals. It ensures that polluted air does not spread around the workshop and is directly channelled into the filtration unit. To satisfy the demands of large cutting workplaces, material section workbenches are designed in such a way that the only section extracted is the one above which the cutting takes place.

For individual technologies requiring extraction and subsequent air filtration the following can be recommended:
➢ Fumes from the thermal cutting (plasma, flame, laser) – extraction directly at the source of the fumes using an extraction workbench.
➢ Welding fumes – depending on the nature of the workshop, extraction of the total volume of air in the workshop, a fume exhaust hood or local extraction using an extraction arm or workbench.
➢ Grinding – local extraction by means of extraction walls and extraction workbenches.
➢ Dust from blasting of metallic materials – typically, extraction from the entire blast box area or in a manner defined by the manufacturer of the device.

The filtration of the polluted air takes place either directly in the filter towers or in the filtration unit, to which it is fed through air ducts. The filtration unit can also be used for special applications in the field of building materials production, the processing of plastics and wherever dry, non-sticky, non-explosive dust emissions are generated.

For the filtration itself, polyester or polyester are successfully used with PTFE membrane materials with a separation efficiency of 99.9% for particles ≥ 0.2 μm classified as "M" according to DIN EN 60335-2-69. Filtered clean air can be returned to the production area if the workplace is supplied with at least 15% outdoor air from the filtered volume.