Can-filters original CAN 350 BFT

The 350 BFT is the first filter in the range with a 40 cm outer diameter and a 6.5 cm carbon bed. It is 50 cm long, weighs 27 kg and holds 17 kg of pelletised carbon. Practical capacity is quoted at 713 m³/h against 900 technical, and the connection is 250 mm.

Where that odd figure of 713 comes from

Every other filter in this range ends on a round number and this one does not. The 713 is not a marketing choice and not a typo: it is calculated.

Can designs the Original range around a contact time of 0.1 seconds. That is the minimum time a parcel of air has to spend inside the carbon layer to give up its odour molecules. Adsorption is not infinitely fast: a molecule has to meet a pore and bond to it, and if the air moves too quickly it shoots straight past.

From that 0.1 seconds, the thickness of the bed and the surface of the cylinder comes a maximum air speed, and from that comes a flow rate. For this body it is 713 m³/h. The technical 900 is what physically passes before resistance becomes unworkable, but at that setting the contact time has become too short and the filter lets odour through.

Practical is therefore always the number you choose your fan against. Technical is the limit of the material, not of the filtration.

The fans Can names for it

From our stock, the Iso-Max 200 at 870 m³/h, the Can-Fan RK 200 at 820 and the RK 200 S at 830 appear on Can's list. All three sit above 713 and below 900, which is the intended working zone: reserve enough to pull through the filter, without driving the air through it.

Technical Specifications:

• Version: steel
• Housing length: 50 cm
• Outer diameter: 40 cm
• Weight: 27 kg
• Carbon kind: pelletised
• Carbon weight: 17 kg
• Carbon bed: 6.5 cm
• Technical capacity: 900 m³/h
• Practical capacity: 713 m³/h
• Connection: 250 mm flange
• Maximum conditions: 70 percent humidity, 80 °C

Frequently asked questions

May I put a 900 m³/h fan on it?
You may, but turn it down. Above 713 the contact time gets too short and odour passes, while you are under the impression you are filtering more.

So is 713 the real capacity?
Yes. Work your installation out against that figure and use the 900 only to see how much room is left above it.

Why is this filter so much fatter than the 366 BFT?
Because the bed goes from 5 to 6.5 cm and the cylinder from 30 to 40 cm. Together that is 17 kg of carbon against 12 kg.

Can I use 200 mm ducting?
The flange is 250 mm. A reducer works, but it pinches exactly where this filter needs its room.