Extraction systems’ benefits are to improve personnel working conditions and the quality of the products manufactured, by extracting polluting fumes and dust particles created in the manufacturing processes.
A centralized extraction system is required when there is a necessity to clean airflow that is rich of fumes, vapors, odors, and dust particles. To purify it, a filtering media is installed before the airflow is expelled into the atmosphere.
All the extraction systems are subject to specific regional and national regulations that set the minimum quantities and dimensions of pollutant particles that can be expelled into the atmosphere.
An extraction system is composed of the following components:
– Extraction arms and/or nozzles: based on the process, or the machine for which the airflow extraction is required, the most efficient method to capture the pollutants are studied. For example, it is possible to install fixed or mobile aspiration nozzles, extraction arms mounted on walls, or directly linking machines to the extraction systems through flexible pipes.
– Pipelines: it links extraction arms and nozzles to the filtering media. Extremely important is correctly dimensioning the diameters of the pipeline, which frequently is tens of meter long, to overcome the pressure drop (ΔP) caused by the pipeline length and the filtering media. The risk of a bad dimensioning is whistling or noises caused by the high airflow speed, or on the contrary an insufficient extraction airflow volume.
– Filtering media: Dependently on the type of process or machine, the pollutant particles formed are made of different substances, of different dimensions, as well as the relative air humidity and its temperature. Hence, the correct choice and dimensioning of the filtering media is key to an efficient extraction system. Based on the process, a sleeve, pocket or cartridge filter may be chosen. If necessary, a cyclone or scrubber may be added to remove larger particles.
– Electric fan: the intake airflow and power dimensioning are two critical parameters for an efficient extraction system. Particularly, the fan’s job is to guarantee enough airflow also at the furthest aspiration stations (where the pressure drops are highest), but at the same time, the average airflow speed needs to be sufficiently low to avoid generating whistling and noises. Moreover, the airflow speed entering the filtering media is one of the parameters characterizing its efficiency and, as such, it needs to be taken into proper account.