Flottazione Flotation - Beverage Process
Flottazione Flotation - Beverage Process
Flottazione Flotation - Beverage Process
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<strong>Flotation</strong><br />
Separating solids from a liquid medium by means of flotation is a<br />
technique that has been in use in many production sectors for a long<br />
time. It is also widely used in the wine processing sector.<br />
It basically involves introducing very small air bubbles into the must which<br />
bind to the suspended solids and draw them up towards the surface.<br />
The compressed gas is dissolved in the must at about 7 bar in the<br />
pressure reactor where it remains for the time required to create the floc.<br />
Clarifying agents (bentonite, gelatine, silica sol) are usually added to<br />
optimise the efficiency of the system. These create agglomerates that<br />
incorporate and adhere to the gas whilst stabilising proteins and phenols.<br />
The process may be either continuous or discontinuous.<br />
In the first case, the solids are separated in a cylindrical tank, an integral<br />
part of the machine, with baffles on the sides which separate the liquid<br />
from the solids and concentrate them in the supernatant in the middle of<br />
the tank. Suction pipes then collect them and send them to the vacuum<br />
filtering process. Discontinuous processing involves keeping the must with<br />
dissolved gas in a tank or basin.<br />
When the container is full or when there is no more product to treat, there<br />
are two separate layers: clear liquid at the bottom and lees at the top.<br />
The clear liquid is drained from the bottom of the container.<br />
VELO S.p.A. produces various types of flotation tanks to meet the<br />
requirements of a wide range of users.<br />
For continuous processing, models FLA and FLB are fitted with pressure<br />
reactor, additive tanks, peristaltic pumps and automatic dosing unit.<br />
VELO also produces three discontinuous models:<br />
PFB, unit with pressure reactor, centrifugal pump, compressed gas inlet,<br />
gas dosing unit and product prefilter;<br />
PFC, unit without pressure reactor where the gas is dissolved and<br />
standardised by means of a patented system.<br />
It is fitted with a centrifugal pressurisation pump, compressed gas inlet<br />
and product prefilter;<br />
PFD is a simplified variant of the previous model with a dual-impeller<br />
centrifugal pressurisation pump which also mixes the air.<br />
This is introduced proportionally to the rate of flow of the liquid by<br />
means of a special Venturi tube.<br />
PFD PFC PFB