Improvement in apparatus for fixing fabrics

Abstract: A vessel (6) provided with entry and exit channels (2, 3) for the fabric piece (4) contains a rotary drum (7) and heat sources (12) for creating in situ a steam environment below a predetermined water level (Z), not necessarily below the drum axis. The drum (7) is partly immersed in the aqueous mass, so that the fabric (4), which moves with and over the drum (7), passes from the aqueous mass to the steam environment and then back to the aqueous mass. Means are provided for controlling the water level (Z) in the vessel (6).

Description: This invention relates to improvements in apparatus for fixing fabrics in piece form, for example woollen or mixed fabric, of the type comprising a vessel containing a rotary drum and means for heating an aqueous mass contained in the vessel, in which in passing from an entry channel to an exit channel the fabric piece passes over and with the drum and is subjected to a pressure greater than atmospheric, at least in the portion passing over the drum (e.g. EP-A-0 324 164). Although known apparatus of this type give adequate results, they are bulky and relatively slow. An object of the present invention is to improve apparatus of the stated type in such a manner as to reduce their overall size while at the same time increasing productivity, but without any loss of fixing quality. This and further objects which will be more apparent from the detailed description given hereinafter are attained by the improvements of the invention, according to which the drum when in operation is only partly immersed in the aqueous mass with the result that a part of it lies in a steam environment, the fabric piece passing from the aqueous mass to the steam environment and then returning to the aqueous mass in moving over the drum. The invention will be more more apparent from the detailed description of a preferred embodiment thereof given hereinafter by way of non-limiting example with reference to the accompanying drawing in which: Figure 1 is a vertical schematic cut-away view of the machine of the invention; Figure 2 is a section through a detail of the entry and exit channels; Figure 3 is a section on the line A-A of Figure 2; Figure 4 is a vertical schematic cut-away view of a further embodiment; and Figure 5 is a still more schematic view of the machine of Figure 4 in a different mode of operation. Although the machine to be described can be used for fixing fabrics other than woollen or mixed woollen fabrics, it is mainly intended for fixing this type of fabric. It is well known that wool is formed structurally of keratin, which is a complex natural compound based on mutually bonded amino acids, the most important of which are cystine, tyrosine, serine, glutamic acid, histidine, lysine and arginine. The intrinsic elasticity of wool fibre derives mainly from the cystine, which contain two sulphur atoms forming cystinic bridges. The elasticity is also due, but to a lesser extent, to other saline bonds and hydrogen bridges originating from electrostatic attraction between hydrogen atoms and oxygen atoms of carboxylic groups. To give the fibre dimensional stability (ie to reduce its intrinsic elasticity) it would therefore appear necessary to act on its structure at the said "elastic" points. Cystines hydrolyze only in hot water or by the use of strongly reducing or oxidizing agents, while the other described bridges separate in the presence of steam. The current art therefore uses two different machines to obtain the desired result, namely a first machine in which the fabric is treated with hot water or hot water solutions, and a second machine in which the fabric is treated with steam. The invention proposes an improved machine of the type initially stated, which is able to provide the two combined actions to thus obtain the desired stabilization with both cost and equipment advantages, as will be apparent from the ensuing description. The machine of the invention shown in Figures 1, 2 and 3 comprises a stainless steel vessel indicated by 1 and containing a vertical entry channel 2 and a vertical exit channel 3 for the open-width fabric piece 4. Between the two channels 2, 3 and hydraulically connected to their lower part at 5 there is a substantially closed chamber 6 of lesser height than said channels. Said chamber contains a drum 7 rotated by conventional motor means, not shown, a pressure roller 8 (which presses against the drum 7 via the fabric 4, for which purpose it is for example idly mounted on the ends of levers 9 urged at their other end) and a semicircular hood or panel 10 incorporating electrical resistance elements or steam or superheated water heating tubes 12 on the side facing the drum 7, about which said panel 10 is concentrically arranged a short distance therefrom to form an interspace 11 along which the fabric 4 moves. The panel 10 is substantially semicircular, with its axis of symmetry forming an angle of about 45° to the vertical. When the apparatus is fully working, the entry and exit channels 2, 3 are substantially full of water or aqueous solution, whereas its level within the chamber 6 is substantially less (indicated by Z) because the resistance elements or the like 12 create above this level a steam environment of a pressure such as to compensate this difference in the water column between the channels 2, 3 full of water (or aqueous solution) and the level Z. The water level, or rather a level between a maximum and a minimum about Z, is maintained by conventional level controllers, eg comprising probe, proximity contactor, or float means, such as indicated at 13, mounted on levers 14 and acting on contacts which switch the resistance elements or other heating means 12 on and off and make up the consumed water with water entering through the pipe D (or D1 in Figure 4) and previously heated with steam. Advantageously the pressure roller 8 is located such that its pressing action on the fabric 4 is exercized substantially at the level Z to force air from the fabric, this air being discharged via known separator valves 60 which allow air but not steam to pass. The valves 60 can also be controlled by the water level control means 13. The inclined arrangement of the heater panel 10 means that this is partly immersed in the water even under operating conditions, where Z is the water level. Situated about the mouth 20 of the entry channel 2 and about the mouth 21 of the exit channel 3 there is an overflow water collection vessel, leading to discharge via pipes 22. Instead of or in addition to the overflow water collection vessels (at 20, 21) there can be provided at the top of the channels 2 and 3 (see Figures 2 and 3) retention means (not sealed) consisting on two opposing sides of flat polytetrafluoroethylene elements 70 fixed to said channel tops by bolts 71, and on the remaining opposing sides of bent polytetrafluoroethylene elements 72 with a spring steel core 73 forming a V and fixed with bolts 74, to prevent dangerous hot water splashes. The water which overflows runs into a pipe 75 leading to discharge. The fabric 4 passes through the V 72. At the base of the two channels 2, 3 in proximity to the two points of hydraulic connection 5 to the chamber 6 there are provided heating resistance elements 25 (or indirect steam or superheated water coils) According to a preferred embodiment of the invention, to increase the fabric treatment time there is provided in the entry channel 2 a succession of rollers 30, all driven and arranged in such a manner as to compel the fabric 4 to undergo a zigzag path which descends between one roller and the next. To adjust the fabric tension, that roller 31 close to the passageway 5 can be movably mounted, eg pivoted and suitably counterweighted (to form a kind of floating roller) or can comprise a known load cell to adjust the operation of the rollers and thus set the fabric tension to the desired value. The exit channel 3 can comprise a similar arrangement, although for constructional simplicity this channel preferably comprises deflectors 40 which although not hindering the movement of the fabric prevent hot water splashing during the ascent and scalding the operator. From the aforegoing it is apparent that during its movement through the described machine, the fabric piece 4 is subjected to the action of hot water (in the channels 2, 3 and in the chamber 6 below the level Z) and to the action of steam in the chamber 6 above the level Z, preferably after squeezing by the roller 8, these actions stabilizing the treated fabric. Rollers 50 guide the fabric 4 onto and from the drum below the level Z. The embodiment shown in Figures 4 and 5 uses a stainless steel vessel indicated by 1A and comprising a vertical entry channel 2A and a vertical exit channel 3A for the open-width fabric piece 4A. Between the two channels 2A, 3A and hydraulically connected to their lower part at 5A there is a substantially closed chamber 6A of lesser height than said channels. Said chamber contains a drum 7A rotated by conventional motor means, not shown, a pressure roller 8A (which presses against the drum 7A via the fabric 4A, for which purpose it is for example idly mounted on the ends of levers 9A counterweighted at their other end) and an arched hood or panel 10 of circular arc shape incorporating electrical resistance elements or steam or superheated water heating tubes 12A on the side facing the drum 7A, about which said panel 10A is concentrically arranged a short distance therefrom to form an interspace 11A along which the fabric 4A moves. The panel 10A extends through an angle exceeding 180°, with its axis of symmetry forming an angle of about 60° to the vertical. The entry and exit channels comprise three parallel sections 2A1, 2A2, 2A3 and 3A1, 3A2, 3A3 arranged in parallel and traversed in opposite directions by the fabric 4A. The fabric 4A is transferred from one section to the next by motorized rollers 101, 102 and rollers 31A. To adjust the fabric tension, these latter can be mounted movable, eg pivoted and suitably counterweighted (to form a kind of floating roller) or can comprise a known load cell to adjust the operation of the rollers 101, 102 and thus set the fabric tension to the desired value. The sections 2A1 and 3A1 are partly occupied, preferably in their upper part, by a series of deflectors 40A which while not impeding the movement of the fabric 4A prevent liquid splashing outwards. Heating means 103 can be provided in the bottom of these sections. The sections 2A2 and 3A2, comprise spaced-apart parallel facing pairs of radiant panels 104, 105 between which the fabric 4 passes. In the lower part of these sections there are also provided further heating means 103 and a conventional floating roller 104, and in the top of the section 2A2 there are provided conventional screw wideners 105, the purpose of which is to keep the fabric widened. In the top of the sections 2A3 and 3A3 there are also provided spaced-apart parallel facing pairs of radiant panels 106, 107, between which the fabric 4 passes. In the top of the section 3A3 there are provided conventional screw wideners 105A identical to the said wideners 105. Finally, further heating means are provided in the bottom of the sections 2A3 and 3A3. In the chamber 6A upstream of the drum 7A there are provided in succession a deviation roller 108, a conventional motorized toothed roller 109, a further deviation roller 110 and a pair of conventional selvedge stretching plates 111, downstream of the drum there being provided in succession a deviation roller 112 and a floating roller 113. The chamber 6A is upperly connected to a vessel or chamber 114. A water/air separator valve 115 is provided at the vessel, at a level higher than the sections 2A1 and 3A1. The separated water is recovered and fed into the sections 2A1 and 3A1. The vessel 114 is connected to a safety pressure switch 116 which discharges excess overpressure. At the exit of the section 3A1 there is a conventional device 120 for widening and centering the fabric 4A. The fabric 4A is then led between a pair of squeezing rollers 121 pressed against each other. The fabric is then passed through a vessel 121 containing water at ambient temperature, in which it undergoes thermal shock. The fabric then leaves the apparatus under the control of a group of rollers 122. When the apparatus is fully working, the entry and exit sections 2A1 and 3A1 are substantially full of water or aqueous solution, whereas its level in the other sections and in the chamber 6A is substantially less (indicated by Z) because the resistance elements or similar heating means 104, 105, 12A etc. create above this level a steam environment of a pressure such as to compensate this difference in the water column between the sections 2A1 and 3A1 full of water (or aqueous solution) and the level 7. The inclined arrangement of the heater panel 10A means that this is partly immersed in the water even during operation, where Z is the water level. Situated about the mouth of the entry section 2A1 and about the mouth of the exit section 3A1 there is an overflow water collection vessel, leading to discharge via pipes. For machine operation, the fabric is firstly inserted and the machine then completely filled with the aqueous treatment liquid, eg water, after which the heating means are operated with consequent generation of steam which forces water from the respective regions until the level Z is reached, when the level control means control the heating means and the feed of make-up liquid. If the level rises these control means again activate the heating means. If the level falls they add treatment liquid, and so on. From the aforegoing it is apparent that during its movement through the described machine, the fabric piece 4A is subjected to the alternate action of hot water (in the channels 2A, 3A and in the chamber 6A below the level Z) and to the action of steam in the sections 2A2, 2A3, 3A2 and 3A3 and in the chamber 6A above the level Z. In the method of operation described in relation to Figure 4, the liquid level Z is equal in the sections 2A2, 2A3, 3A2 and 3A3 and in the chamber 6A, or in other words the pressures are equal in the regions occupied by steam. As shown in Figure 5 it is however possible to operate differently, with the steam pressure in the chamber 6A exceeding that in said sections, as indicated by the liquid levels Z₁, Z₂, Z₃. This is advantageous in that the fabric is subjected not only to the alternate water and steam action but also to different pressures. In the latter case, the steam pressure in the chamber 6A is equal to the sum of the two heights h and H (the first measured between the levels Z₄ and Z₃ and the second between the levels Z₂ and Z₁,). For this purpose, the common points of the sections 2A2, 2A3 and 3A3, 3A2 are connected to a pipe 200, 201, the two pipes opening into a chamber 202 which is connected to a pressure control valve, the chamber 6A being upperly connected to a vessel 204 connected to a further pressure control valve 205. The valves in question discharge to atmosphere any pressure higher than a determined threshold value, which in the case of the valve 203 is h and in the case of the valve 204 is H + h . The procedure for attaining these operation conditions is as follows. The machine is filled with the aqueous treatment liquid, for example water, and the heating means 104, 105, 106, 107 are operated. As a result of the heating, the steam displaces the liquid from the sections 2A2, 2A3 and 3A2, 3A3 to the level Z₃, the valve 203 then operating to prevent further fall in level. A part of the displaced liquid leaves the sections 2A1 and 3A1 and the other part flows into the vessel 204, which is of sufficient capacity. The heating means 12A in the chamber 6A are then operated. Steam forms until liquid is forced from the chamber 6A to the level Z₁, which is maintained by the valve 205. The displaced liquid enters the sections 2A3 and 3A3 which attain the level Z₂. The represented conditions are thus attained. Liquid is lost during operation (for example to the fabric and in the form of steam through the valves 203, 205). To compensate for this, known means for controlling the levels Z₁ and Z₃ are provided to cause adequately heated make-up liquid to flow into the chamber 6A (the liquid must be pressurized) via a valve K and into the tops of the sections 2A1 and 3A1. In the embodiment of Figure 4 in which the levels Z are equal, a single pressure control valve 301 is used connected to a common point 300 connected to the vessel 114 and to the tops of the sections 2A2, 2A3 and 3A2, 3A3.

Claims: Improvements in apparatus for fixing fabrics, for example woollen or mixed fabric, of the type comprising a vessel (6, 6A) containing a rotary drum (7, 7A) and means (12, 12A) for heating an aqueous mass contained in the vessel, in which in passing from an entry channel (2, 2A) to an exit channel (3, 3A) the fabric piece (4, 4A) passes over and with the drum (7, 7A) and is subjected to a pressure greater than atmospheric, at least in the portion passing over the drum (7, 7A), characterised in that the drum (7, 7A) when in operation is only partly immersed in the aqueous mass with the result that a part of it lies in a steam environment, the fabric piece (4, 4A) passing from the aqueous mass to the steam environment and then returning to the aqueous mass in moving over the drum (7, 7A). Improvements as claimed in claim 1, characterised in that the level (Z) of the aqueous mass is controlled by known control means (13). Improvements as claimed in claim 2, characterised in that the control means (13) operate on the heating means (12, 12A) and on the feed of heated water (D), and possibly on the air discharge (60). Improvements as claimed in one or more of the preceding claims, characterised in that at least the entry channel (2) is provided with drive rollers (30) for the fabric (4), which are arranged in such a manner as to compel the fabric to follow a zigzag path, preferably of continuously downwardly inclined sections. Improvements as claimed in claim 4, characterised in that means (31, 31A) are provided in the entry channel (2, 2A) for controlling the tension in the fabric (4, 4A). Improvements as claimed in one or more of the preceding claims, characterised in that the heating means (12, 12A) substantially concentrically surround the drum (7, 7A) and are unsymmetrical about the vertical to the extent that when in operation a part of them remains immersed in the aqueous mass. Improvements as claimed in one or more of the preceding claims, characterised by comprising a pressure roller (8, 8A) acting on the fabric (4, 4A) lying about the drum (7, 7A). Improvements as claimed in one or more of the preceding claims, characterised in that the channels (2, 3, 2A, 3A) are hydraulically connected to the vessel (6, 6A) via a passageway (5, 5A) arranged substantially at their base. Improvements as claimed in one or more of the preceding claims, characterised by consisting of means (70, 73) for preventing the hot water and steam, in ascending, from leaving the entry and exit channels (2, 3) too violently, with the danger of scalding the operator. Improvements as claimed in claim 9, characterised in that the means (70, 73) are formed with sliding gaskets of materials having a high sliding coefficient in moist environments. Improvements as claimed in one or more of the preceding claims, characterised in that the entry and exit channels (2A, 3A) are formed of at least two sections (2A1, 2A2, 2A3; 3A1, 3A2, 3A3) traversed by the fabric in opposite directions, one (2A1, 3A1) being for water and provided with deflector means, and the other (2A2, 2A3; 3A2, 3A3) being for steam, and being provided with heating means (104, 105; 106, 107) for generating steam in them. Improvements as claimed in claim 11, characterised in that after the exit channel (3A) there is provided a vessel (121) containing water at a temperature less than that of the liquid contained in the chamber (6A) in order to subject the fabric (4) to thermal shock. Improvements as claimed in claim 11, characterised by comprising means (such as 30) to maintain the pressure acting on the aqueous treatment liquid in the steam environment of the chamber (6A) and the pressure in the steam sections (2A2, 2A3; 3A2, 3A3) equal. Improvements as claimed in claim 11, characterised by comprising means (such as 203, 205) for obtaining different pressures on the aqueous treatment liquid in the steam environment of the chamber (6A) and in the steam sections (2A2, 2A3; 3A2, 3A3).

Inventors: BERTOLDI ATTILIO, BERTOLDI, ATTILIO
Applicants: BERTOLDI ATTILIO, BERTOLDI, ATTILIO
Application year: 1991
Main classification: D06C7
IPC codes: D06C7