Air Filters

Ambient Air Filters by
Thor Filtration
including media compatible with Microclene Filters

The elimination of ambient dust is a further step in the three-point strategy to avoid the problems caused by inhaled dust in the woodworking workshop.  Despite any dust extraction we may use, there will always be residual dust in the atmosphere and it is the removal of this dust which is addressed by the well-proven, quiet, very efficient  and effective Ambient Air Filters which cost a few pence per day to run and typically filter to 0.4 micron .  Having used such a device in my own workshop for many years I can attest to the great improvement these filters make in the working environment.

For many years we have been happy to supply the Microclene units but these have now become unavailable.

We have been able to source replacement filters and media with similar sizes and specifications from another British company, Thor Filtration,  and we are pleased to be able to offer these and thus to break the hiatus in availability of quality ambient air filters.

Through our relationship with Thor Filtration we are now also able to offer continuity of supply of filter media for owners of Microclene filters as well as a directly compatible range of filter units of equivalent performance. The table below provides a cross-reference from Microclene products to the equivalent Thor Filtration products. Please refer to this when ordering filter media for an existing Microclene unit. For any unit not mentioned in the table or in the product listing, please drop us an email query as we may be able to assist.

To select the correct size for you workshop, bear in mind that you should be looking to achieve at least ten air exchanges per hour, so for example in a 35 cu. m. workshop you need to select a unit with a throughput of at least 350 cu. m. per hour. (e.g. TF470)

Model Reference

Filter Flow Rate
Cu. m/hour


Size (mm)






53 watt

 205 dia. x 180 long (excl. foot)




60 watt

205 dia. x 250 tall




60 watt

205 dia. x 335 tall




100 watt

300 x 300 x 130




100 watt

305 dia. x 230 tall




90 watt

308 dia. x 216 tall




90 watt

308 dia. x 390 tall




90 watt

308 dia. x 290 tall




330 watt

500 x 1000 x 400




4 x 100 watt

500 x 500 x 450




62 watt

200 x 165 x 260 tall

All units operate from a 220 volt single phase AC supply and are equipped with a standard UK three-pin plug moulded to the supply lead.
Entries in red indicate discontinued units: however, filter media may remain available for these models - please check the listings, below.

Thor Filtration are building thier range of filter units and media as quickly as prudent development allows. As new units become available, we will add them to our range.

Bear in mind that you can order Thor filter media to fit your existing Microclene unit. Please note that Thor media is vacuum packaged for easier storage and transit. The media should be carefully removed from the packaging and allowed to re-expand to original size before attempting to mount it in your filter unit.


A visual model reference to Thor Filters is provided here.

Left: The smallest of the Thor ambient air filters, the TF250, is suitable for smaller workshops with volume up to a maximum of 20 cubic metres. It can be bench mounted, as shown or, with a little ingenuity, suspended from a ceiling.

Right: Designed for ceiling mounting, suspended by its chains, the TF470 will suit medium workshops. Care should be taken to ensure that the unit is hung well clear from likely head impact - a safety device which is a hazard is not a good idea! Arrange to suspend the TF470 from two hooks, not a single central point, since this will resist the torque wind-up during starting and stopping and make the machine more stable.

TF810 Ambiient Air Filter from Thor Filtration

Left:  The TF810 from Thor Filtration is designed to be mounted either on a wall or screwed to a ceiling using the neat built-in lugs.
With the large front inlet and generous filter area the TF810 is a real dust-eater.  The position of the outlet vents on the rear quarters has enabled the exhaust airstream to be directed parallel to the mounting surface leaving the work area free of draughts.
The unit may even be used free-standing on a bench or worktable, if required.

The Microclene model MCP, right, is designed to improve the working conditions for pyrographers operating in an enclosed space by filtering the abstracted air through an activated carbon filter which combines with the dust filter element to remove not only fine dust and fibres, but also odours and smoke.

We have limited quantities of these original Microclene Pyrography filters and media remaining available. Once this stock is exhausted, all products supplied will be from Thor Filtration.


*NB: Prices quoted in pounds sterling. 
Value Added Tax will be added to invoices to EU residents unless
a valid VAT registration number is quoted when ordering.

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1997-2006 P. Hemsley.  The information on this website is the copyright property of Peter Hemsley. 
Coeur du Bois and The ToolPost are trading styles of Peter Hemsley.  Whilst reasonable efforts are made to ensure the accuracy of information presented, no liability can be accepted for errors in this information nor for contingencies arising therefrom.  If you are inexperienced in any aspect of woodworking, we would strongly counsel that you take a course of formal instruction before commencing to practice