F Series potabilizers - Facet International - #1

casing. With a radiation level of 2.573 A, a significant transformation occurs in the metabolism of the cells. This is followed by a slowing down of their reproductive functions until the bacteria are totally eliminated.

Facet fresh water potabilizers have two main constituent parts:

• RE-HARDENING FILTER

• STERILIZER

The distilled water, which comes from the evaporator or from the storage tank, is passed through the generator's re-hardening filter, where the water flows uniformly through the bed of mineral salts and takes them up. In this way, the necessary re-hardening, or pH adjustment, is achieved.

Next, part or all of the mineralised water passes through the treatment chamber of the sterilizer,where it is treated using ultraviolet radiation.

In the next page, we can see a typical flow diagram.

The models (F-75 to F-2000-2) incorporate a mineral salts regeneration system.

Facet potabilizers are designed to meet the need on board ship to treat the water produced by evaporators, in such a way as to produce suitable drinking water. This is achieved using the processes of re-hardening and sterilization

RE-HARDENING OF WATER: This process consists of adding mineral salts to distilled water, in sufficient quantities to achieve a pH of between 7.5 and 8, always below 12 °F.

The water produced by the on board water evaporators has the following characteristics:

• Salinity: Between 0.5 and 4 ppm of NaCl

• pH: ~6

• CO2 content: 40 mg/l.

• Oxygen present.

The pH value of ~6 is caused by the presence of carbonic gas,which is produced by the decomposition of the carbonates present in sea water. This gas is found dissolved in the distilled water

When the mineral salts are added to distilled water, the CO2 is neutralised and the pH of the water is increased.

STERILIZATION OF WATER: Once the necessary mineral salts have been added, the water must be sterilized to remove the bacteria which have survived the process of evaporation, which takes place under vacuum conditions and at 60 °C.

This sterilization is carried out using ultraviolet radiation.

With this method, the water which is to be treated is passed through a chamber where it is subjected to radiation from U.V. generators. These generators are isolated from the water by means ofa protective, isothermic

• Skid assembly

• UV sensor

• Automaticdoser

• Activecarbonfilter

• By-pass to the sterilizer

• By-pass to the rehardening filter

• By-pass to the active carbon filter

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