CRSI - CENTRO RICERCHE SVILUPPO IMPIANTI - BELT DRIERS FOOD INDUSTRY
Belt
driers food industryare those devices in which the product is left to
dry over a tape generally crossed by hot air.
The tape in
continuous motion is contained within a metal structure which permits
the necessary aerothermic circuit.
Drying plants based on ETL
system are obtained combining the different elements each defined by
a particular air circuit.
Usually the models are
- Belt driers
food single-belt air recirculation
- Belt driers food simple
single belt
- Belt driers food multinastro superimposed
Principle
of operation
Belt driers food industry is produced by a flow of hot air that, in the
most efficient systems, through the layer of product.
Then the
same principle of "fluid bed" with the important difference
that, in envi case, there must be no transport, and should be limited
to very air velocity.
The product in the early stages is generally
very moist and can be treated with high temperatures without being
deteriorated.
Subsequently, as the belt towards the drain, there
was a reduction of the heat transfer coefficient, as well as a
significant reduction in volume and weight of the treated
material.
For this reason belt driers food industryare divided into
sections each with a tape progressively slower, so that the height of
a layer of the product remains constant, reducing the area required
and the cost of the machinery.
Each machine is divided into
"zones", each with a different temperature, speed and
direction of air.
The production capacity of ETL obviously varies
according to the treated product.
In the case of fruit and
vegetables you can be considered a value of 15-25 kg / h of
evaporated water per m² of tape, with an energy consumption that
varies from 900 to 1250 Kcal / Kg of evaporated water.
Belt driers food industry are mainly used in the food industry and the chemical
industry.
The material is then typically stainless steel.
