MACHINE FOR THE TREATMENT OF FABRICS

The present invention relates to a machine for the treatment of fabrics such as, for example, purging, bleaching, dyeing, washing, in which the fabric is kept in the extended state during the processing.

Machines of this type are commonly known as "jiggers" and normally consist of a tank, through which the fabric passes, kept in an extended state by guiding cylinders and in some cases by .bars fixed on oscillating arms during its alternating winding and unwinding movement on two main cylinders. The fabric consists of pieces sewn together to form a long strip which is unrolled from one of the main cylinders and, after passing through the bath, is wound onto the other cylinder and vice versa during the whole treatment of the fabric. Each passage from one cylinder to the other is called "straightening" .

The passage rate of the fabric from one cylinder to the other and the tension exerted on the fabric itse If, which vary significantly from the beginning to the end of the piece due to the different diameters, are kept constant by the control of the moving devices of the main cylinders which are effected with the use of various systems, for example by means of oil-dynamic control centres, electric motors, inverters, encoders,

charge cell sensors, etc.

The dyeing process in the machine can be run in its various phases by establishing a priori the times of the single phases, or as happens more frequently, by controlling the number of "straightening passages" necessary for completing the single phases . This allows the same dyeing cycle to be used regardless of the length of tissue effectively loaded in the machine.

Machines of this type have the advantage of not subjecting the fabric to particular mechanical stress and also treating extremely worn articles, but they also have various limitations.

With the same characteristics of the fabric and treatment to be effected, for example, the length of the process times corresponds to that of the strip of fabric to be treated.

Considering that in the best of hypotheses the maximum advance rate of the fabric ranges from 100 m to 150 m per minute and that strips over 4000 m long can normally be treated, the time for a single "straightening" can quite often be over 20 minutes and the dyeing cycle exceed well over 8 hours .

This also causes possible non-uniformity during the treatment, making it more difficult to keep the composition constant in the treatment bath during the

whole "straightening" passage, and a greater heat differential is created between the fabric wound onto the cylinders and the treatment bath, phenomena which, if not controlled correctly, can cause processing defects .

Furthermore, the treatment time limits the maximum loading capacity of machines currently produced (maximum diameter of the cylinder with the fabric wound 1400 mm approximately) , as a greater quantity of metres would require excessively long treatment times and the risk of non-uniform treatment.

The present invention intends to overcome the above drawbacks by proposing a machine in which the strip of fabric to be treated is divided into at least two strips and wherein each strip of fabric is treated on a pair of main cylinders, which are all contained in the same machine unit .

In this way, the present invention allows a drastic reduction in the dyeing times, energy consumption, vapour and chemical products with respect to the machines so far produced, in addition to guaranteeing greater uniformity and producing machines capable of treating much higher quantities of fabric.

An aspect of the present invention relates to a machine for the treatment of fabric comprising a

machine unit, in which, preferably in the lower portion there is at least one tank containing a treatment bath for the fabric, characterized in that inside said machine unit, there are at least two processing modules of the 'fabric, wherein each of these comprises a pair of winding/unwinding rolls of a strip of fabric, which by rotating in one direction or the other allow the passage of the fabric from one roll to the other passing through said tank. The characteristics and advantages of the machine according to the present invention will appear more evident from the following description of two illustrative and non-limiting embodiments, in which the enclosed figures represent: - figure 1 schematically illustrates a machine for the treatment of fabric according to a first embodiment of the invention;

- figure 2 schematically illustrates a machine for the treatment of fabric according to a second embodiment of the invention

With reference to the above figures, the machine according to the present invention comprises a machine unit 2, preferably cylindrically shaped, in which, preferably in the lower portion 3, there is at least one tank containing a treatment bath 4, for example a

dye bath. Inside said machine unit, there are at least two processing modules of the fabric, wherein each of these comprises a pair of winding/unwinding rolls 51, 51'; 52, 52' of a strip of fabric T, T', which by rotating in one direction or the other allow the passage of the fabric from one roll to the other passing through said tank. Said winding/unwinding rolls are suitably driven by mechanical, oil-dynamic, hydraulic or electric motor groups (not shown) to allow a controlled rotation.

Once the treatment has been started, the strip is unwound from one of the two rolls of the pair of rolls on which it is wound, and guided by a series of advance cylinders and extenders 53 and 53', it passes into the treatment bath 4, for example when it is situated in the lower part of the tank 3 by means of at least one lower end cylinder 54 and 54' which is normally immersed in the dye bath, and is then rewound onto the other roll of the pair of rolls. This occurs contemporaneously for each module present inside the machine unit (in the figures illustrated, there are two modules) .

The passage called "straightening" is then repeated in the opposite direction. This alternating movement is repeated for as many times are necessary for completing

the treatment .

The processing modules of the fabric are preferably symmetrical with respect to a central vertical dividing axis Y 'of the machine unit. Furthermore, in the embodiment illustrated in figure 1, the strip of fabric T is rolled onto the winding and unwinding cylinders 51 and 52 so that the portion of unwound fabric is facing the outer side edge of the machine unit. In the embodiment illustrated in figure 2, the strip of fabric T is rolled onto the winding and unwinding cylinders 51 and 52, so that the portion of unwound fabric is facing said central axis Y of the machine unit .

With this configuration, the strips of fabric complete a "straightening" passage, with the same velocity of the fabric, in half the time with respect to the traditional machines equipped with a single pair of cylinders and a single strip. The shorter duration of the treatment consequently leads to greater saving in energy, vapour, auxiliary products, chemical products and water.

When the strips of fabric of different modules have the same length, the rotation rates of the rolls are normally the same. When there are differences in the length of the

strips of tissue T and T' and on the basis of the entity of said difference, the same can be compensated by modifying the velocity of the single pairs of cylinders and/or by delaying the inversion of the movement of the cylinder with the strip having the shorter length.