From the wash cycle to sterilization

Before their use, tanks are washed and sterilized.
The washing cycle is very important, for just the sterilization process would not be enough to remove all bacteria.

WASHING
During the first stage of the washing cycle, a caustic solution is used, which transforms dirt into a biodegradable solution; fat is transformed into soap and removed with water. Subsequently, a rinse is operated, immediately followed by acid neutralization process. Finally, washing is performed with disinfectant, which would be enough to ensure sterility. However, oxygen remains in the tank, which may feed bacteria. For this reason, tanks are washed and then sterilized.

STERILIZATION (we sterilize up to 200 cubic metres)
Sterilization is a process that may be operated through steam or chemicals to remove any living microbe.

Sterilization with steam:
The sterilization process is operated through air removal from inside the tank and steam jet into the tank. The result is formation of condensation. Flowing steam has a temperature corresponding to saturation temperature, i.e. approx. 110° C.
After approx. 40 minutes of rest, steam is replaced with nitrogen, which pressurizes the tank, excluding and replacing the air inside.
The entire tank cools down, releasing heat externally, until a completely aseptic tank is obtained.
The cycle is controlled by an automatic trolley which controls all processes, measuring inlet pressure, recording discharge temperature, and ensuring safety of the entire system, and bringing the container in contact with the outside.

Chemical Sterilization:
The chemical sterilization process is a disinfection process.
The container is filled with acid disinfectant, which functions also as a stabilizer. Usually, an acid iodophor producing raising oxygen is used.
The process is slow: for example, a 300 cubic metre container takes approx. 4 hours to be filled. The advantage is that the solution used to disinfect a tank at the end of the process is not removed, but the disinfectant can be transferred from one tank to another, through an automatic system.


Mixed Sterilization Systems:
The Mixed Sterilization System uses high pressure forced circulation of peracetic acid and hydrogen peroxide. At the end of this process, the tank is emptied and filled with demineralised water, which is transferred from one tank to another. After it has been emptied, the tank remains loaded with nitrogen.

REFRIGERATED TANKS
Refrigerated tanks are mostly used to maintain the temperature of stored products at short term. In fact, the only way to maintain product integrity and limit bacterial growth within acceptable ranges is cold.

External Refrigeration: refrigerated tanks have an external envelope, where water and propylene glycol circulates and keep the temperature of internal fluid at around 1° C. At this temperature, bacterial growth is practically absent.

Internal Refrigeration: through very efficient internal heat exchangers. Exchangers are in direct contact with the product and cooling is very fast.

Turbo Exchanger: through a forced circulation system, with high delivery capacity tubed pump immersed in the container.

Insulated Tanks: the refrigeration system is completed by total tank insulation.
Partial insulation is mainly used in wine-making tanks.