The fabric is treated wide.
The machine is made up of a series of contiguous tanks in which the fabric is desized, washed
and, subsequently, squeezed by two cylinders which have the purpose of removing excess water.
The last tank contains a solution of caustic soda and wetting substances.
Two squeezing cylinders make the sodaing process uniform on the fabric, completing the first phase.
In the second phase, of bleaching, the soda-ash 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 continuous and counter-current washing tanks, alternating hot water
it's cold.
The fabric, cleaned 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, instead of being rolled up, comes
passed directly into the dryer and only when it comes out is it rolled up and made available
for subsequent dyeing and finishing operations.
Particular attention is needed in 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.