In filtration, efficiency indicates what minimal particle size a filter can remove. This primarily depends on the sealing; what ever means are used to make sure the medium can only pass through the filter cloth and not bypass it through a seam or poor sealing. The better the sealing, the finer the filter cloth you can use and the smaller the particles that can be used.
In a belt filter, sealing is quite a challenge since all you have is a flat piece of filter cloth and whatever sealing you use, it may never obstruct the transport of the filter cloth through the unit. In a Q-Filter®, the sealing mechanism is an integral part of the transport mechanism, allowing very tight sealing.
With Q-Filter® it is possible to use filter cloth with an efficiency down to a particle size of 5µ! The picture shows the excellent sealing, noticable from the white tracks where the sealing prevented dirt from passing to the sides of the filter cloth.