Washing process - Textile Section

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Washing and sizing, which have the purpose of removing all impurities (sizing, textile or dirty oil, also resulting from previous processes), can be carried out in three ways:

a. rope washing (for heavy fabrics, mainly carded);
b. wide washing (for light, delicate, combed fabrics, etc.);
c. continuous washing (wide for large productions).
The washing process however consists of four successive phases:
1. Soaking
The fabric is impregnated with water and a mechanical rubbing action eliminates the substances
insoluble, such as earth, dust and unsecured dyes, etc.
2. Prewash
Cold wash, light and fast, which eliminates the excesses of color and dirt that they could
fix on the piece in the subsequent degreasing phase.
3. Degreasing
A water bath containing soaps, detergents and auxiliaries, in which emulsions are emulsified
oiling substances used in the spinning and eventual sizing, oily stains, etc.
The temperature of the bath is fundamental, which varies in relation to impurities and components to be eliminated
(from 20 ° C to 60 ° C).
4. Rinse
With plenty of water the emulsion is removed with all the substances to be removed.
used washing and dry
machine for wash
used washing
Processing technology
The machine consists of:
a) a deep tank, which contains the degreasing solution,
(see figure A, point 1).
b) On the tank there are two squeezing cylinders (fig. A, 2),
adjustable pressure,
c) a rack device (fig. A, 3),
which separates and guides the pieces, blocking
processing at the passage of any
knots of fabric (which raise it).
d) Under the squeezing cylinders
a basin (fig. A, 4) recovers
the emulsion squeezed from the fabric.
e) A coil heats the bathroom.
f) A tube starts from the bowl
drain (fig. A, 5),
closed at certain stages of the process.
g) A series of nozzles (fig. A, 6),
for the introduction of water
in the tub.
h) A drain valve,
at the base of the tank (fig. A, 7).
i) In front and at the top, outside the machine, a cylinder unloads the washed pieces.
j) A control panel allows you to set the parameters and manage the processing.
The machine consists of:
a bath collection and working tank (see figure A, point 1), with an inclined plane, which
presents on the bottom of the drain valves;
a series of fabric widening and tensioning cylinders (fig. A, 2);
a rocker with central pin (fig. A, 3), which holds the pieces in the center of the machine;
small guide cylinders (fig. A, 4), one of which is immersed in a tray called the basin (fig.
A, 5) which has a drain valve, to eliminate the emulsified substances at the end of the path;
above the bowl, two squeezing cylinders (fig. A, 6) with adjustable pressure, which eliminate the
most of the bathroom;
a small intermediate cylinder (fig. A, 7), which is used for small batches or for samples;
a conveyor cylinder (fig. A, 8) for dragging the fabric for normal batches of pieces;
two lateral guides (fig. A, 9), adjustable according to the height of the piece and placed along the inclined plane
of the tank, allow to keep aligned the layers of the pieces in work;
a series of coils for heating the bathroom and a series of nozzles (fig. A, 10) for inlet
of water;
an external affaldatore (fig. A, 11), used when the work is finished for unloading the pieces;
a control panel for setting parameters and processing management.
This processing technology, despite having the same purposes as the two previous treated systems
(rope and discontinuous washing), uses a different method whose configuration includes:
a prewash and rinse tank (figure A);
a storage tank (fig. B);
an impregnation tray (fig. C);
a cooling tray (fig. D).
The above elements can be assembled differently according to the type of washing
that you want to perform and based on the type of fabric to be washed, but the two main steps: group
prewash and rinse (fig. A) and the fabric storage unit (fig. B), are normally found
in each combination and often repeated several times along the way.
Let's see some examples of combination of steps that can constitute a machine:
fabric introducer, fabric impregnation pan, fabric storage tank, two
prewash and rinse tanks with outfeeder or rewinder (fig. 1);
fabric introducer, prewash and rinse tank, storage tank, two prewash tanks
and rinsing, cooling tray, stapler or reel at the outlet (fig. 2);
fabric introducer, impregnation tank, storage tank, prewash tank e
rinse, storage tank, two pre-wash and rinse tanks, cooling tank,
bundler or reel (fig. 3).
Washing continuos open
It is evident that the so-called prewash and rinse tanks, depending on the position they occupy
in the chain, they do real washes, where the countercurrent water can reach a temperature
about 40/50 ° C in relation to that taken in the storage tank, which it can reach
i 98 ° C.
It is useful to know in more detail the process that takes place in the four groups listed above:
prewash and rinse tank (fig. A). The fabric, guided by cylinders (fig. A, point 2),
it passes under the nozzles (fig. A, 1) fed countercurrent by the bath taken from the filter tank.
An excess part of the bath remains in a wedge between the fabric and the cylinder (fig. A, 2) and pushed by
the latter penetrates the patches during the advance.
The other excess bath part not retained by the fabric is sent to the filter tank by a
conveyor (fig. A, 3).
Subsequently also the other face of the fabric is washed by other nozzles (fig. A, 4) with the same
previously indicated method (fig. A, 5) and the excess bath pushed by
another conveyor (fig. A, 6) for another filter tank.
A series of small conveyor cylinders (fig. A, 7) controlled carries the piece between two squeezer cylinders
(fig. A, 8), then goes to the tank of the next treatment foreseen in sequence.
Fabric storage tank (fig. B). In this tank the fabric is subjected to the operation of
soaping with diluted bath with independent recirculation. It is possible to work both in high bath and in
low bathroom. A series of coils (fig. B, 1) on the bottom of the tank heat the bath up to 98 ° C.
The piece, coming from the previous tank of the machine, passes through the bathroom
a series of drive and return cylinders (fig. B, 2) where it is soapy.
As it advances, the fabric is kept tight and enlarged by a series of cylinders until
reaches the squeezer (fig. B, 3). Then it passes into the tank of the next scheduled treatment.
Fabric impregnation tank (fig. C). When provided, this tank equipped with coils
heating element (fig. C, 1) is inserted at the start of the machine.
The fabric, coming from the pallet, passes into the soaking bath through a cylinder (fig. C, 2)
and, subsequently above and below the conveyor cylinders (fig. C, 3) where it receives the jet of the wedge
bath through two sprayers or nozzles (fig. C, 4),
then it passes through a tensioner / expander (fig. C, 5) and a squeezing unit (fig. C, 6) placed
outside the machine which conveys the fabric to the following machine of the process.
Fabric cooling tray (fig. D). It is placed at the end of the car and it is
built with a two or three cylinder foulard (fig. D, 1) placed outside the body of the machine.
This section of the process can be used for normal cooling of the tissue
it occurs through two water sprayers at room temperature but can also be used for addition
of any auxiliary products that the fabric may need. The other parts of the tank are the same
to those indicated for the impregnation tray (fig. C).
Given the different solutions that this machine allows, the prewash and rinse tank (fig.
A) which normally works in countercurrent, can exclude every single tank if it comes
used for independent treatments with different bathrooms. Each tank is also equipped with a pump
of recirculation of the bathroom.
used machine

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