Alvito Filter insert ABF Duplex SD

2 filter stages for clean results

The ABF Duplex SD filter insert consists of two successive filter stages. The activated carbon block is followed by a bundle of microfine hollow fibre membranes as the second filter stage. Due to the design and pore size of the hollow fibres of 0.1 µm, the ABF Duplex SD delivers hygienically perfect water at a high flow rate of approx. 7.0 litres per minute. What all Alvito filters have in common is that they have a pore thickness of 0.45 μm and do not allow bacteria to pass through. The duplex cartridge is the pinnacle of development here and would even filter out viruses at 0.1 µm. Even if viruses have not yet been found in German drinking water, the Duplex gives a good feeling and is also suitable for use abroad. But that's not all, because one of the main factors in favour of the ABF Duplex SD is the connection to water pipes with low pressure.

So it's ideal if a high water flow rate is required, even if the water pressure from the pipe is rather low. This is an advantage when the whole family gathers in front of the filter system in the morning to fill up their water bottles. The duplex also has a positive effect on the under-sink filter if the existing tap is used during installation and all cold water is filtered. The influence of the filter insert on the Viva water swirler is also positive. The increased flow rate further increases the effectiveness of the Viva's swirl chambers. We even explicitly recommend the Viva water swirler when using the Duplex filter unit, as the Duplex is not manufactured in a version with EM ceramics, but the fresher and softer flavour does not have to be sacrificed.

Innovative technology with measurable results

Basically, the Alvito filter inserts with their high activated carbon content offer outstanding filter performance, which is achieved by minimising the use of binding agents. In order to achieve a higher flow rate with the duplex cartridge (7 litres instead of 4 litres per minute) without sacrificing filter fineness and retention values, a special technology was developed. The pores of the activated carbon block have been slightly enlarged (1.50 µm) to achieve the higher flow rate. The combination with the hollow fibre, through which the water must pass after contact with activated carbon, then ensures a fineness of 0.1 µm. Compared to the three other filter inserts, this means that the flow rate of the Duplex almost doubles and the filter fineness improves from 0.45 µm to 0.1 µm. As the excellent suitability of activated carbon in connection with the production of clean drinking water has been sufficiently proven, the combination with the hollow fibre brings a noticeable gain in comfort and purity. Where other manufacturers only use loose granulate in their filter cartridges, the Alvito Duplex activated carbon block technology offers two further benefits: significantly larger contact surfaces of the activated carbon with the water flowing through and the small pore thickness of the hollow fibre, which presses the water through the pipe pressure and blocks many particles and suspended solids.

With a filter fineness of 0.1 μm, these pores are many times smaller than a human hair, which has a diameter of around 100 µm in comparison. The ABF Duplex SD premium standard filter insert delivers the best water for small and large households every day. With a total filter capacity of 6000 litres over 6 months, it is slightly behind the Primus SD, EM and CLC filters (8000 litres), but in most households, 30 litres of filtered water per day should be more than enough capacity.

Imitation of natural depth filtration in Alvito filter inserts

During the production of the Alvito filter inserts in Germany, high-quality activated carbon is specially activated and manufactured or baked into a solid block in a complex sintering process. These block filters have an extraordinarily large number of extremely fine pores and channels through which the water flows during filtration. There is therefore no direct transit of the water through a filter cartridge that only uses activated carbon granulate. The water flows from pore to pore, covering a much greater distance than the size of the block would suggest. The distance and surface area that the water comes into contact with as it flows through is estimated to be up to 100 football pitches. The surface area achieved with just one gram of activated carbon powder is 1,300 square metres. This achieves an effect comparable to natural depth filtration in the smallest of spaces.

Minerals are retained in the water

One advantage of these activated carbon block filter systems is that dissolved minerals such as magnesium, calcium and potassium remain in the water and the natural mineral balance is maintained. This is also the case with the Duplex SD. These minerals remaining in the water can have an extremely positive effect on the flavour of the water, especially in combination with the Viva water swirler. In addition, the quality of the filter inserts means that there is no need to add silver for disinfection.

This innovative Alvito technology not only achieves outstanding filter performance, but the water flow rate of all four filters is also so high that the WaterWhirler Viva can be operated with them.