Technical field of the invention

The present invention relates to the washing of fabrics subsequent to their industrial processes of weaving and printing, and more particularly to a roller for an apparatus that allows to carry out a method for washing fabrics in the modes known in the art as "continuous" and "open", which respectively indicate the fact that fabric webs pass through a washing apparatus from the inlet to the outlet completely distended in the width direction.

Background

In industrial weaving processes, washing is necessary to remove impurities such as weaving residues from greige or semi-finished fabrics, as well as chemicals such as caustic soda and bleaching products. In the case of removal of weaving oils, the washing is more intense and requires specific solvents, for this reason this operation is generally referred to as "scouring".

Washing and scouring are generally performed before heat-setting treatments to avoid oxidation of fibers of a fabric and their consequent yellowing.

Known washing apparatuses for fabrics comprise one or more washing units inside which tanks are housed for containing washing and rinsing liquids. Inside the washing units, rollers or cylinders are rotatably mounted which define a washing path for a fabric web extending from an inlet to an outlet of the washing unit itself.

The washing is carried out with liquids such as mixtures of water with detergents, soaps and/or solvents, for example limonene, or only with water at temperatures between 20°C and 99°C. The washing of a fabric may be carried out by immersion in washing liquids, typically first in tanks containing mixtures of water with detergents, soaps and/or solvents and then in tanks containing only water for the rinsing operations, or by spraying by means of jets delivered from spraying bars provided with slits and/or nozzles which are arranged along the washing path. Washing apparatuses that employ combinations of immersion tanks and spraying bars are also known.

Italian patent 102013902142642 describes a machine for continuously scouring a web of fabric comprising a washing tank suitable for containing a washing liquid and means for heating the latter. The machine further comprises a plurality of rollers which define a washing path, along which a web of fabric is conveyed, and spraying means arranged along the washing path above the level of the washing liquid contained in the tank. The first and second nozzles are arranged so as to direct the respective fan jets onto the same area of the fabric web in transit, in order to cancel the resulting force of the forces directed perpendicularly thereto without resorting to supporting rollers.

The Italian patent 102013902188808 describes an apparatus for washing fabrics in continuous and open mode comprising at least one treatment unit in which a plurality of cylinders are arranged which define a washing path from an inlet to an outlet. The treatment unit comprises a first and a second perforated movement surfaces configured so as to receive a strip of fabric to be treated sandwiched between them. The movement surfaces are supported by a set of cylinders with which they form a closed loop path.

Similarly to the Italian patent 102013902142642, the treatment unit further comprises a plurality of first and second nozzles arranged along the whole washing path above the level of the washing liquid contained in the tank and facing towards the perforated movement surfaces for delivering washing fluids against the opposite faces of the fabric transported sandwiched by them.

Notwithstanding the availability of machines and methods for washing and scouring fabrics in continuous and open mode, there is still the need to improve the washing and/or rinsing processes and the relative apparatuses both from the point of view of effectiveness in removing impurities as well as regarding the speed of treatment. The need to have the possibility of carrying out treatments different from a simple washing treatment by using a same apparatus is also felt.

Summary of the invention

The technical problem addressed and solved by the present invention is therefore that of providing a roller for a fabric washing and/or rinsing plant in continuous and open modes which allows to overcome the aforementioned drawbacks with reference to the prior art.

This problem is solved by a roller according to claim 1. This roller, intended to be installed in a washing or rinsing tank immersed in a washing or rinsing liquid, is internally hollow with a perforated lateral wall for returning a fabric web. Inside the roller and at a distance from the perforated lateral wall, a hollow cylinder is installed having an inlet opening of a fluid, selected from the group consisting of washing or rinsing liquid, air, steam or a mixture thereof, and spray holes of this fluid arranged on the lateral wall of the cylinder and oriented so as to remain immersed in the liquid contained in the washing tank or in the rinsing tank. The perforated lateral wall of the roller is configured to rotate around the cylinder so that the fluid pumped into the cylinder through the inlet opening flows out through the spray holes, immersed in the liquid contained in the washing tank or in the rinsing tank, directed towards the perforated lateral wall for returning the fabric web.

Preferred features of the present disclosure are the defined in the dependent claims.

The apparatus according to the present disclosure comprises at least one washing unit which houses at least one washing tank and/or a rinsing tank, or two washing or rinsing tanks arranged in series in a processing direction, and also a plurality of rollers which define in the washing unit itself a washing path which develops in the working direction from an inlet to an outlet. Between these rollers there is at least one roller as defined in claim 1 immersed in the washing tank and/or in the rinsing tank.

The apparatus of the present disclosure allows to implement an effective method of washing and/or rinsing a continuous web of fabric in contact against a lateral wall of a roller while the roller is immersed in a washing or rinsing liquid contained in a washing tank or in a rinsing tank.

Other advantages, features and methods of use of the present invention will become apparent from the following detailed description of several embodiments, presented by way of non limiting examples.

The claims as filed are an integral part of this description and are herein incorporated by reference.

Brief description of the figures

Figure 1 is a front view of a washing roller according to the present disclosure with the lateral wall in semi-transparency, having an internal cavity containing a cylinder with a plurality of nozzles.

Figure 2 is a profile view of the washing roller of Figure 1. Figure 3 is a rear view of the washing roller of Figure 1 with the lateral wall in semi-transparency.

Figure 4 shows a washing apparatus, according to the present disclosure, of fabrics with a washing tank and a rinsing tank, each comprising a roller of Figure 1, and a continuous web of fabric F which runs on the rollers moving in a forward direction L.

Figure 5 shows the washing apparatus of Figure 4 without the fabric web to be washed.

Figure 6 is a perspective view of the washing apparatus of Figure 5 in which the front surfaces of the rollers in the washing tank and in the rinsing tank have been removed to show the internal structure.

Figure 7 is a rear view of the washing apparatus of Figure 5.

Detailed description of preferred embodiments

Figures 1 to 5 show a roller according to an embodiment of the present disclosure and Figures 4 to 7 illustrate a relative plant for washing fabrics in the continuous and open modes.

The washing system comprises at least one washing unit 110 inside which at least one washing tank and/or a rinsing tank is housed. The illustrated embodiment shows the washing unit with two tanks arranged in series in a working direction schematically indicated by an arrow L. These tanks can be two washing tanks 111 and 112, or two rinsing tanks 111 and 112, or even a washing tank 111 designed to contain a washing liquid, for example a solution of water and detergent, wetting or swelling chemical product and a rinse tank 112, intended to contain a rinsing liquid, for example water.

In the discussion that follows reference will be made to the case in which both tanks are two tanks of the same type, i.e. two washing tanks or two rinsing tanks 111 and 112, which are connected by pipes 116 and 117 which convey the dirty liquid (washing liquid or rinsing liquid) to a same filter, as shown in figure, so as to produce a liquid filtered by impurities and pollutants, which can be recirculated in the tanks themselves to limit waste or be discharged without polluting the environment. However, what will be said holds, mutatis mutandis , also for apparatuses with a washing tank and a rinsing tank or for apparatuses with more than two tanks (for washing and/or rinsing) or with one tank only (washing or rinsing). Generally, inside the washing unit 110 rollers that define a washing path are housed. In the embodiment shown in the figures, there are two emerged motorized rollers H3a, an emerged return roller H3b and two immersed motorized rollers H3c in the washing or rinsing water, all rotatable about its own axis, which together define a washing path for a fabric web F, which extends from an inlet 114 to an outlet 115 of the washing unit 110.

The motorized rollers H3a and H3c are rotated by respective electric motors Ml through transmission belts and/or gears, so as to drag the continuous fabric web F in the washing apparatus and to get it out from it in the forward direction L.

Preferably, according to one embodiment all the rollers H3a, H3b, H3c are motorized so as to minimize any friction problems with the fabric web in transit, that may cause undesired elongations.

As shown in Figures 4 to 7, the motorized rollers H3c are disposed close to the bottom of the respective tank, thus in an operative condition of the apparatus they works immersed in the washing or rinsing liquid, while the other rollers are spaced therefrom and are located outside the bath of washing liquid or rinsing liquid, in an operating condition of the apparatus. It will be understood that this configuration of the washing unit 110 allows washing a fabric web by immersion in the tanks 111, 112. In other words, the arrangement of the rollers is such that the washing path extends partially outside the tanks 111, 112 and partially inside them.

According to this disclosure, the immersed rollers 113c are realized as shown in Figures 1 to 3 so as to further improve the effectiveness of the washing. Each roller H3c has a perforated lateral wall 121 which defines a perforated external lateral surface, which rolls on the fabric to be washed, and an internal cavity visible through the openings from the front surfaces 122 of the rollers H3c. A cylinder 123 is contained in this internal cavity and has an inflow opening 124 of a fluid, selected in the set consisting of washing or rinsing liquid, air, steam or a mixture thereof, and has spray holes 125 defined on the surface side of the cylinder 123.

According to this disclosure, the spray holes 125 of this fluid are oriented so as to remain immersed in the liquid contained in the washing tank 111 or in the rinsing tank 112. The roller H3c is configured to rotate around the cylinder 123 so that the fluid pumped into the cylinder 123 through the inflow opening 124 comes out through the spray holes 125, immersed in the liquid contained in the tanks (for washing or rinsing) 111 and 112, directed towards an internal lateral surface of the roller 1 l3c.

With the roller of the present disclosure shown in Figures 1 to 3, it is possible to spray a fluid against the fabric F while it is in contact with the immersed roller H3c. Moreover, the fluid jet is directed from the inside of the roller towards the outside, so that it favors the detachment of processing residues and other impurities from the face of the fabric facing the outside of the roller, which is normally the face which is printed or which undergoes to other surface treatments.

Such a result would not be obtainable with a jet of fluid directed against the fabric from the outside of the immersed roller. In fact, in this circumstance, the impurities generated during the printing process, present on the outside of the fabric, would be pushed to enter more deeply instead of detaching from the fabric.

Finally, the fact that the holes 125 from which the fluid is sprayed are immersed in the liquid contained in the washing or rinsing tank, also allows to spray steam or air alone or mixed with water or other liquid, so as to create different cleaning actions on the continuous fabric web F.

To wash even better the fabric F, it is preferred to install, along directional lines of the inner side surface of the roller 113c, several fins 126a and 126b, preferably of different height and different length, alternating with a regular step high fins 126a to low fins 126b. It has been found that by installing the high fins l26a alternated to the low fins l26b along the inner lateral surface of the roller H3c, a turbulent movement of the liquid inside the roller is induced during the rotation of the roller 113c which forces the liquid to cross the fabric web in contact with the outer lateral surface of the perforated wall of the roller H3c, further improving the effectiveness of the washing of the fabric web F.

According to one embodiment, the cylinder 123 is substantially stationary with respect to the respective tank 111 or 112, while the roller H3c rotates around its own axis.

According to an alternative embodiment, not shown in the figures, the cylinder 123 is constrained to the washing unit 110 rotatably about its own axis and, when it is in operation, it is made to oscillate by electric motors connected to gears or belts rotating in a direction and in the opposite direction. Thanks to this possibility of oscillating the cylinder 125, it is possible to change the spray direction and further improve the effectiveness of the cleaning.

Preferably, the immersed rollers H3c intended to work in the tanks 111, 112 have a greater diameter of the emerged rollers H3a and H3b, thereby enabling to lengthen the path in immersion of the fabric web without having to increase the number of rollers. This configuration also allows to reduce the stresses on the fabric web. The use of larger diameter rollers in the tanks than those arranged above them actually reduces the volume available for the washing liquids, which offers the advantage of requiring a smaller amount of liquid both in the washing phase and in the rinsing phase.

The washing liquid and the rinsing liquid are supplied by respective tanks (not shown) of the plant which are connected to the tanks 111 and 112 of the washing unit 110.

The washing liquids feeding the tanks 111, 112 are kept at the desired temperature by suitable heating means, for example serpentine pipes 118, 119.

The plant also comprises a plurality of spraying means 120 arranged along the washing path in the sections above the tanks 111, 112, so that a fabric web F can be treated both by spraying and by immersion. The spraying means 120 can be realized as described in international patent application PCT/IB2018/053793, on behalf of the same applicant, comprising a plurality of spraying bars constrained to the washing unit 110 transversely to the washing path, thus having respective axes substantially parallel to those of the rollers, and comprising respective nozzles, or alternatively slits, configured for dispensing jets of liquid towards the faces of a fabric web F in transit. The spraying bars are arranged so as to direct the jets of liquid against the opposite faces of the fabric web. In the illustrated embodiment six spraying bars are shown, by way of example, arranged above the tank 111, and six spraying bars are arranged above the other tank 112.

It will be understood that the number of rollers and spraying bars is not a binding element. Preferably, the spray bars are constrained to the washing unit 110 rotatably around their respective axes and are operatively connected to rotating drive means, for example pulleys fitted on their axes and toothed belts connected to one or more motors M2 of the washing unit 110. The operation of the spraying bars for example can be managed by an automatic control system (not shown) of the washing apparatus.

The present invention has been described so far with reference to preferred embodiments. It is to be understood that there may be other embodiments which pertain to the same inventive core, as defined by the scope of the claims set forth below.