The fabric is treated broadly.
The machine is made up of a series of adjacent tanks in which the fabric is desized and washed
and, subsequently, squeezed by two cylinders which have the purpose of removing the excess water.
The last tank contains a solution of caustic soda and wetting substances.
Two squeezing cylinders standardize the soldering process on the fabric, completing the first phase.
In the second phase, bleaching, the soda fabric passes:
in a tray containing diluted hydrogen peroxide;
in a steam chamber, with a sufficiently long path for the development of oxygen;
in a series of washing tanks continuously and against the current, alternating hot water
it's cold.
The fabric, clean and bleached, comes out of the machine, is rolled up and taken to the dryer.
Where there is a continuous drum dryer, the wet cloth comes instead of being rolled
passed directly into the dryer and only at the exit of this is it rolled up and made available
for subsequent dyeing and finishing operations.
Particular attention must be paid to the choice and dosage of the oxidizing products to be used,
in relation to the type of impurities present on the fabric to be treated.