APPARATUS FOR THE CONTINUOUS WET FIXING OF WOOLEN, MIXED WOOLEN, SYNTHETIC MATERIAL AND COTTON FABRICS

Abstract: The apparatus comprises; a container (1) having an entrance (7) and an exit (8) for the fabric (T), a rotary drum (12) disposed in said container, means provided in the container to direct the fabric onto the drum from said entrance or from the drum to said exit, a cover (19) provided in the container and partly surrounding the drum at a distance therefrom to thus define with the drum an interspace (17) along which the fabric moves, heating means (18) disposed in correspondence with said interspace, and means (3) for feeding water into the container.

Description: This invention relates to an apparatus for the continuous wet fixing of woolen, mixed woolen, synthetic material and cotton fabrics of the kind recited in the preamble of the main claim. It is well known that before or after undergoing scouring and/or fulling, fabrics are subjected to thermal treatment known as fixing, the purpose of which is to prevent the formation of creases or to remove creases which have already formed during previous treatment, and to give the fabric the necessary dimensional stability. The thermal treatment can be done either wet or using steam. In either case it comprises heating the fabric (for example immersed in water) to a temperature at which all the fibres assume a certain plasticity followed by sudden cooling. Two types of fixing apparatus exist, one continuous and one batch. The batch apparatus is in the form of an autoclave with which the optimum fixing temperature of more than 100°C can be reached. This apparatus has however the drawback of a labour requirement plus low productivity due to the small quantity of fabric which it treats. Thus, this apparatus operating a batch method suffers from the inherent drawbacks of the method itself. Although the continuous apparatus allows higher productivity it is unable to heat to the optimum temperature, with the result that either the results are unsatisfactory or it uses a considerable quantity of costly steam without obtaining adequate results in view of the difficulty of correctly and uniformly controlling the fibre temperature. GB-A-2 152 085 discloses an apparatus for the continuous wet heat treatment of fabric. This known apparatus comprises a container having an entrance and an exit for the fabric, a rotary drum disposed in the container, means provided in the container to direct the fabric onto the drum from said entrance and from the drum to said exit, means for feeding water into the container, and heating means within the container. The high temperature within the apparatus is obtained by blowing superheated steam thereinto. The heating means do not serve to generate heat in the container and more particularly at the fabric level but only to bring the relatively cold treatment liquids coming from the container outside to the inner temperature of the container so to have the liquid propelled onto the fabric at said inner temperature. The known apparatus makes also use of large amounts of steam. FR-A-2 362 231 discloses an apparatus for reducing some defects in dying fabrics. The fabric moves along an interspace between a rotary drum and stationary arcuate guiding member partly contouring the drum. No heating means are provided at said member or in the cooperating drum. An object of the present invention is to provide an apparatus for the wet fixing of fabrics which can operate continuously while heating the treated fibres to their optimum fixing temperature. This and further objects which will be more apparent from the detailed description given hereinafter are attained by an apparatus according to the characterising clause of the appended main claim. The invention will be more apparent from the detailed description given hereinafter with reference to the accompanying drawings which show a preferred embodiment thereof and in which: Figure 1 is a diagrammatic vertical section through the apparatus of the invention; Figure 2 is a side view of the seal means; Figure 3 is a section on the line III-III of Figure 2. In the figures the reference numeral 1 indicates overall a container contructed of stainless steel sheet and provided with insulation, not shown. The container is connected to a source 2 of pressurised water, preferably heated, by way of a valve 3. The container also comprises a bottom drain 4 controlled by a valve 5, and conventional heating means 6 preferably of electrical type. The container comprises an entrance 7 for the fabric T to be subjected to the fixing operation and an exit 8 from which the treated fabric leaves. Between the entrance and exit the container comprises a roof 9 in the form of a cylindrical segment, at the top of which there is provided a pipe 10A of adequate height, such as 6-10 metres, for discharging the steam. In correspondence with the entrance 7 and exit there can, as shown, be provided identical seal means indicated by 10 and shown in detail in Figures 2 and 3, and which will be described hereinafter, although such means are not essential. If the seal means 10 are not provided, the entrance 7 and exit 8 can be positioned at an adequate height from the ground, for example approximately equal to that of the pipe 10A. Within the container there are provided means 11 in the form of idle rollers, the purpose of which is to guide the fabric T such that it adheres to the outside of a drum 12 disposed within the container and driven by conventional motor means, not shown, in the direction of the arrow F. The drum can be provided with interconnected channels 13 positioned close to its periphery and traversed by a heating fluid, such as steam at 140-160°C, which respectively enters and leaves through the hollow shaft 14 of the drum 12 and ducts 14, 15 provided in this latter. A certain distance above the drum and concentric thereto there is provided a cover substantially of cylindrical segment shape in cross-section. Between the drum 12 and cover 16 there is therefore present an interspace 17 through which the fabric T passes in contact with the drum. On that surface of the cover 16 facing the interspace 17 there is provided a pipe coil 18 traversed by a heating fluid, such as steam at 140-160°C originating from any suitable external source. The cover is of metal and is insulated on the surface facing away from the interspace 17, as indicated by 19. The height of the pipe 10A is chosen such that there is no appreciable escape of water at the pressure at which the apparatus operates. To discharge steam which forms in the interspace 17 there is provided a rising pipe 50 having a height equal to or greater than the height of the pipe 10A. After feeding the fabric T along the path indicated by the dashed line, the container is filled with hot water and this water is kept under pressure, preferably such that its boiling point, referred to sea level, reaches 103-104°C. Heat is then applied by means of the resistance element 6, steam is fed for example at 140-160°C to the channels 13 of the drum 12 and to the pipe coil 18 of the cover 16, and the drum 12 is driven to advance the fabric T in the direction of the arrows F1. The steam generated by the water escapes through the pipe 10A. During this stage the fabric T undergoes wet-heating by which its fibres reach a substantially plastic state to allow effective continuous fixing to be obtained. To prevent water loss at the apparatus entrance 7 and exit 8, the seal means 10 shown in detail in Figures 2 and 3 can be provided. These means comprise a pair of main rollers 20, 21 faced with a layer of relatively very elastic elastomer. The main roller 20 is supported idly between the sides 22 of the entrance 7 and exit 8 respectively. The main roller 21 is supported idly in slides 23 mounted slidable rectilinearly in guides 24 rigid with said sides. The slides are connected to the rod 25 of a single-acting cylinder-piston unit 26 (provided with a return spring) connected to a pressurised fluid source, not shown. The cylinder-piston units are supported by the structure of the entrance 7 and of the exit 8 respectively, their purpose being to urge the roller 21 against the roller 20 to the extent of compressing their facings, such that their contact does not take place along a line but over a relatively large area. The fabric T passes between said rollers 20, 21. Against each of the main rollers there acts a secondary roller 30 of equal length, supported on a pair of end cradles 31. Said cradles comprise an inner recess 32 and an outer shoulder 33, the purpose of which is to centre the secondary roller 30 so that its ends are coplanar with those of the main rollers (see Figure 3). The cradles are hinged at one end (at 34) to a support 35 rigid with a flat metal plate 36 having the same length as the rollers and inclined so that the relative secondary roller adheres to it under the thrust of a torsion spring 37 positioned at the hinge 34 and acting on the cradle to tend to rotate it in the direction of the arrow G to thus bring the relative secondary roller 30 into contact both with the main roller 20, 21 and with the flat plate 36. A rectilinear elastic gasket 40 adheres against each side of the flat ends of the main and secondary rollers and against the sides of the flat plates 36, it comprising (see Figure 3) an axial air chamber 41 and a slot 42 by which it is mounted on the right angle-bent arm 43 of a bracket 44 rigid with the sides 22 of the entrance 7 and exit 8. As the main rollers 20, 21 undergo the stated considerable compression in their mutual contact region, said gaskets, which also extend into the compression region, thus ensure an effective seal thereat.

Claims: An apparatus for the continuous wet fixing of woolen or mixed fabrics, comprising: a) a container (1) having an entrance (7) and an exit (8) for the fabric (T): b) a rotary drum (12) disposed in the container (1); c) means (11) provided in the container (1) to direct the fabric (T) onto the drum (12) from said entrance (7) or from the drum (12) to said exit (8); d) means (2) for feeding water into the container (1); e) heating means (13,18) within the container (1), characterized in that a cover (16) is provided in the container (1) to define with the drum (12) an interspace (17) along which the fabric (T) moves and that the heating means (13,18) are disposed in correspondence with said interspace. An apparatus as claimed in claim 1, characterised in that the heating means (18) are provided on or in the cover (16). An apparatus as claimed in claim 1, characterised in that the heating means (13) are provided in the drum (12). An apparatus as claimed in claim 1, characterised by comprising at least one vent pipe (10A) having a height exceeding that of the water column corresponding to the water pressure within the container (1). An apparatus as claimed in claim 1, characterised in that the means (2) for feeding water into the container (1) keep the water under pressure in the container. An apparatus as claimed in claim 2 or 3, characterised in that the heating means (13,18) are ducts or channels fed with steam. An apparatus as claimed in claim 1,characterised in that at the entrance (7) and exit (8) there are provided seal means comprising: cooperating main rollers (20,21) provided with an elastically deformable facing; inclined plates (36); secondary rollers (30) each cooperating with a main roller (20,21) and with a plate (36); rectilinear gaskets (40) cooperating with the main rollers (20,21) and secondary rollers (30) and with the plates (36). An apparatus as claimed in claim 7, characterised in that at least one main roller (21) is urged against the other main roller (20). An apparatus as claimed in claim 7, characterised in that the secondary rollers (30) are elastically supported. An apparatus as claimed in claim 9, characterised in that the secondary rollers (30) are supported by hinged cradles (31) which are elastically loaded. An apparatus as claimed in claim 1, characterised in that in order to keep the water under pressure in its interior, the entrance (7) and exit (8) have a height exceeding that of the drum (12) such that they form barometric columns.

Inventors: BERTOLDI, ATTILIO
Applicants: BERTOLDI, ATTILIO
Application year: 1988
Main classification: D06B3
IPC codes: D06B3