There are basically two types: those with a low pressure and high flow rate, and those with a high pressure and lower flow rate. The former are used with machines which produce a high volume of larger chippings, and not so much fine dust, such as planers and moulders. They generally take the form of a twin bag machine, with an impeller being used to blow the debris into the lower waste sack, whilst the upper bag is used as a filter to trap the larger dust particles. They are efficient at dealing with large amounts of waste, though, due to their fairly crude filtration systems and low pressure, they cannot cope with fine dust. The second type of extractor is a vacuum machine. These operate by sucking air through filters to separate out the debris, as in a domestic vacuum cleaner. Because of their high vacuum pressure, far finer filters may be used enabling them to deal effectively with dust. They are used for fine dust producing machines such as sanders and routers. Do not try using a domestic vacuum cleaner for this job as it will rapidly become clogged and may well be damaged. Purpose made workshop vacuums must be used as they have a large filter area, industrially rated motors, and often incorporate useful features such as automatic switching, when used with portable power tools.
Though these two types of extractor seem fairly well defined, there’s a small amount of crossover between the two. High capacity vacuum extractors are available that can cope with both fine dust and large volumes of chippings. These tend to be large and expensive and mainly suitable for use with fully installed systems. Chippings extractors are also now available with finer filters to contain the finer dust, though these are liable to reduce their flow rate and their efficiency suffers if connected to narrow hoses such as those used for power tools. Here we’re testing a selection of chippings extractors, some with fine dust filters. These are mobile machines designed to be pushed around the workshop and connected to each machine in turn, as required.
By Ged Meager
by Ged Meager
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