Extraction system
All systems that remove disruptive particles or gases via air are referred to as extraction systems . From the domestic sector , this includes, for example, extractor hoods , but also gas extractors in laboratories and systems, which help prevent chips from remaining in the air in wood construction. The extraction system is placed as close as possible to the emission in order to clean the room air. They may be equipped with an automatic switch- on.
In metal construction, for example, extraction systems are used in machining. These systems optimize dry processing, because not only the chips are captured, but also the finest dust particles and oil mist residues.
Detection device
Air is used as the carrier medium for the interfering substances. Fans or blowers generate a stream of air that sucks the unwanted substances away.
In the field of extraction technology, the collection of the substances to be extracted is of particular importance. The substances to be extracted are usually harmful to health or pollute the environment so much that they are perceived as a nuisance. In order to use the extraction system in a cost-efficient and energy-efficient manner, the recording device must ideally fully record the interfering substances, if possible without sucking in unpolluted air. In the household sector, e.g. B. in the case of an extractor hood over the stove, the efficiency is increased, for example, by hinged panels on the front. Nevertheless, the efficiency of such a device can hardly be compared with the performance of extraction systems in the industrial sector.
Depending on the application, the suction devices are placed in a housing that encloses the work area, which is especially the case with fully automated production. In other cases, especially for manual work, suction tables or movable collection devices with hoods or suction tips are used.
Filtering and cleaning
Extraction systems for dust and dirt lead the contaminated air into a pre-separation chamber (see cyclone or all-purpose vacuum cleaner ). The heavy fractions are separated in this chamber. The remaining dust can then be separated on the outside of a filter and caught in a dust container. Pre-separation filters can often be cleaned, for example using compressed air.
For filtering respirable particulate matter are HEPA filters used. These are saturation filters and are exchanged because their filtering ability is no longer guaranteed if they are overused.
Systems that have to extract toxic gases often have carbon filters or a wet separator , depending on the substance .
Filters of different particle filter classes are often connected in series in order to increase the service life of the individual filter stages. A pre-separation of coarse particles thus serves to protect the fine-pored fine dust filter.
The filtered air is either returned to the work area or directed outside. For reasons of energy efficiency, an air return is desirable, since no heat is lost in this way. However, the provisions of the Ordinance on Hazardous Substances (GefStoffV) and the specified limit values for concentrations of hazardous substances in the air must be observed. In principle, air can be recirculated after sufficient cleaning for all substances that are not carcinogenic , mutagenic or toxic to reproduction , so-called KMRF substances. Special provisions apply here.
commitment
Extraction systems are used e.g. B. at:
- Extraction of exhaust gases during laser cutting
- Extraction on computer-controlled machines (short: CNC )
- Extraction of soldering vapors ( flux vapors)
- Extraction of engine exhaust gases in vehicle hangars by fire departments
- Extraction of ozone during corona treatment
- Extraction of paper dust in printing machines
- Extraction of suspended dust due to the risk of explosion
- Extraction of chips from woodworking and metalworking machines ( machining )
- Household extractor hood
- Gas extraction during chemical experiments in laboratories
- Sweat fume extraction
- Suction of water, saliva, blood and small parts during the dental treatment
The market for extraction systems in the industrial sector is divided into modular extraction systems, in which the filters are grouped into modules and can therefore be adapted to different applications, and static extraction systems, which are designed for specific applications and can only be slightly adapted.