SYSTEM FOR COLLECTING AND REMOVING DUST IN A DOUBLE-BEAM VERTICAL LOOM

Abstract: A system for collecting and removing the dust in a double-beam vertical weaving loom, of the type comprising two warp beams (2), two weaving lines and two cloth beams (8) which are all arranged opposite one another, comprises three lines for collecting and removing the dust which forms during the weaving operations. Two of said lines (13), which are identical, are respectively arranged underneath the warp stop devices (12) of said opposite weaving lines, while the third of said lines (14) is arranged in the central part of the loom underneath the two sets of heald frames (4) of said weaving lines.

Description: SYSTEM FOR COLLECTING AND REMOVING DUST IN A DOUBLE- BEAM VERTICAL LOOM The present invention relates to a system for the collection and removal of tufts of dust and fluff arising from the processing of yarns in weaving looms. In particular, the collecting and removing system according to the present invention has been designed for vertically arranged double-beam weaving looms. As regards a general description of vertically arranged double- beam looms, reference should be made to the jointly pending Italian patent application No. MI91 A002079, in the name of the same Applicant, the contents of which are understood as being incorporated herein for the sake of reference. In the description below, reference will be made to only some aspects of the vertical loom which are of particular relevance to the present invention, with a brief illustration being given of the remainder of said loom for a better understanding of the description provided below. The problem of removing dust and fluff from weaving machines is much more important than it might seem at first sight. In fact, during the weaving of yarns - in particular when natural fibres and high-speed looms are used - huge quantities of dust and fluff form in the zones where rubbing of the warp yarns occurs (warp stop device, yarn guides, healds, reed), said dust or fluff, with time, getting together to form lightweight tufts of considerable volume. These tufts, which are of negligible weight, tend initially to remain attached to the warp yarns until - owing to the various obstacles encountered by these yarns as they move forward or because of the greater volume and hence weight which they have acquired - they become dislodged and fall downwards. The tufts which have thus formed accumulate on the ground, underneath the loom, or more particularly on the various obstacles represented by the parts of the loom intercepting their falling movement, creating with time true and proper balls of dust. In both cases, these accumulations of dust must be frequently removed in order to avoid damage to the warp yarns, to the fabric being formed and to the weaving elements. In fact, if the aforementioned tufts of dust are conveyed along as far as the weaving zone, i.e. into the vicinity of the beating-up reed, they create not insignificant problems not only as regards the efficiency of the loom, since they may cause breakage of the warp yarns or weft stoppages due to an irregular opening of the shed and hence corresponding interruptions in operation of the loom, but also as regards the quality of the fabric since they may become trapped and drawn along by the warp yarns and "woven" with them, leaving visible signs on the fabric even after their removal, so that the quality thereof can be worsened. In fact, although it is possible to operate manually downstream of the weaving zone by removing the tufts of dust which have become woven in the fabric, the compactness and uniformity of the fabric are irreversibly damaged by this operation, leaving a zone of fabric where weft and warp yarns are looser and arranged more irregularly, so as to create a visible defect. An effect of lesser importance, but nevertheless of relevance, is the possibility that the dust which has accumulated in the vicinity of the dislodging zones may be picked up by the weaving loom mechanisms, causing seizing and operational malfunctions. A further drawback, which is certainly not insignificant, arises from the accumulation of dust and fluff in the immediate vicinity of delicate weaving components, such as the healds. This accumulation gradually hinders the regular movement of the warp yarns, increasing the tension of the yarns and, finally, resulting in breakage thereof. Still further drawbacks occur owing to the formation of said tufts of dust on the warp yarns in the region of the weft insertion zone. The presence of said tufts in fact hinders conveying of the weft, reducing the efficiency and precision of the jet of the secondary nozzles. It has been noted, moreover, that the presence of the tufts does not leave the neighbouring warp yarns perfectly free, resulting in them remaining attached and trapped during opening of the shed, to the point of preventing sometimes this operation from being performed correctly. There is therefore a high probability that this situation may cause breakage of the warp yarns which have remained trapped, while in any case it prevents the regular travel of the weft. All the drawbacks described above have as a final consequence that of worsening the quality of the fabric and at the same time reducing the efficiency of the loom, owing to the stoppages necessary for repairing the broken yarns. There is therefore the urgent need for a dust removal system which is efficient and not excessively onerous from a cost point of view. If we consider the aspects of the problem in more detail, it must be remembered that the abovementioned points where the dust is dislodged consist of the various mechanical components of the weaving loom which - to the extent that they limit the dimensions of the channels conveying the warp yarns or stress the latter mechanically - constitute an obstacle for the movement of the tufts of dust which are therefore necessarily dislodged from the warp yarns. Generally, therefore, the preferential points where said tufts are dislodged consist of the heald frames and the warp stop device. It must also be emphasized that the arrangement of the weaving components is determined by requirements of a purely functional nature and it is therefore difficult to take into account also the need for optimisation of the preferential points for dislodging of the dust. On the contrary, it is often the case that, in order to limit the dimensions, the weaving components are arranged very close to one another and partially superimposed, so that it is unlikely that the tufts of dust will be able to fall freely towards the ground. Consequently, the tufts, when they become detached from the yarn, fall onto other moving parts of the loom or even onto the warp yarns themselves, thus being drawn along again and recirculated, with a gradual accumulation effect and hence gradual worsening of the productivity and quality problems referred to above. In the known art of horizontal looms of the conventional type, various solutions have been proposed for the removal of said dust residues, with the aim of preventing the dust accumulating in positions which are critical for the operation of the loom. All these various solutions have in common the cleaning technique, which consists in removal of the dust by means of compressed-air jets and immediately afterwards collection thereof by means of air suction into other ducts. For example, conventionally, in large weaving rooms use is made of automatic centralized plants which blow air onto the crucial points of the looms by means of a first series of suitably oriented nozzles and suck the dust so raised by means of a second series of nozzles, both said series of nozzles being movable along guides arranged above the looms. Compressed air, as a vehicle for removal and transportation of the dust, is without doubt excellent from the point of view of cleaning efficiency, since it manages to reach the most delicate points of the loom without interfering in any way with the moving parts thereof. However, the power required for supplying compressed air to a cleaning system such as that described above has a significant negative effect on the overall economy of the weaving plant in terms of energy consumption, since said system has fairly low level of efficiency and therefore requires a high air throughput in order to rapidly remove the dust from the entire loom. Another problem which arises in the systems used hitherto consists in the fact that the compressed air used in the loom cleaning plant, in order to avoid undesirable variations in the ambient conditions, must be the same air used for conditioning the room air and is therefore air which has a high humidity level (70-80%) for weaving purposes. With time, this humidity tends to combine with the dust and fluff, forming sticky masses which at this stage become difficult to remove only with air. Finally, another problem consists in the fact that the dust raised by the blowing nozzles is not immediately and completely collected by the suction nozzles and is therefore dispersed in the weaving room, further complicating the task to be performed by the corresponding conditioning plant. Even worse is the situation of those weaving plants where, in order to avoid the not insignificant additional costs of the abovementioned system of travelling cleaning devices, cleaning of the dust is performed by means of circulation of conditioning air which is injected, after being conditioned and humidified, into the top part of the weaving room and is continuously sucked up by means of special floor ducts arranged underneath the looms, together with the dust which has accumulated therein. This type of cleaning system does not require in actual fact heavy plant installation costs, but, in addition to all the drawbacks already considered above for the travelling cleaning systems, it results in much higher energy costs owing to the conditioning of the large volumes of air which are required and also has an even lower cleaning efficiency, since the suction points are located far from the zones where the dust is produced and in any case dust other than that which has fallen onto the ground cannot be collected. The object of the present invention, therefore, is that of providing a system for collecting and removing the dust from weaving looms, which is not affected by the abovementioned drawbacks and therefore, in particular, has a limited compressed-air consumption and is therefore also able to use air with a low moisture content, without negatively altering the conditions of the ambient air. Another object of the invention is that of providing a cleaning system which is particularly suited for application on double-beam vertical looms, avoiding any problems of dust accumulation which would be particularly damaging in view of the compact structure of this loom. These objects are achieved according to the present invention by means of a system for collecting and removing dust, preferably in a double-beam vertical weaving loom of the type comprising two warp beams, two weaving lines and two cloth beams which are all arranged opposite each other, each of said weaving lines comprising a warp stop device, a set of heald frames and a reed, characterized in that it comprises three lines for collecting and removing the dust which forms during the weaving operations, two of said lines, which are identical, being respectively arranged underneath the warp stop devices of said opposite weaving lines and the third of said lines being arranged in the central part of the loom underneath the two sets of heald frames of said weaving lines. Further characteristic features and advantages of the system according to the invention will emerge, however, more clearly from the detailed description which follows, of a preferred embodiment thereof, provided by way of example and illustrated in the accompanying drawings, in which: Fig. 1 is a cross-sectional schematic view of a double-beam vertical loom incorporating the system for collecting and removing dust according to the present invention; Fig. 2 is a schematic view, on an enlarged scale, of the warp stop device zone of the loom according to Fig. 1 ; Fig. 3A is a plan view of a first embodiment of the suction line for the warp stop device; Figs. 3B and 3C are a longitudinal cross-sectional view and a plan view, respectively, of a second embodiment of the suction line for the warp stop device; and Fig. 4 is a perspective view of the suction line for the heald frames. Fig. 1 shows in schematic form an arrangement of the novel double-beam vertical loom as described in the aforementioned patent application jointly pending in the name of the same Applicant. In brief, the novel loom extends in a vertical direction and has a main body formed by a central frame 1 which has mounted on either side of it the devices forming two complete weaving lines, which are arranged opposite one another and perfectly symmetrical with respect to a central vertical plane. Starting from the bottom zone of the loom, each weaving line comprises a warp beam 2, a drive bar 3 which arranges the warp yarns on a substantially horizontal plane, a warp stop device 12, a yarn- pulling bar 1 1 , a set of heald frames 4, a sley with a reed 5, a take-up cylinder 7 for the newly formed fabric 6 and, finally, a cloth beam. The advantages of such an arrangement are fully explained in the aforementioned patent application, to which reference should be made for a better understanding of the present invention. It is obvious, with regard to what stated above, that in the novel double-beam loom the zones most affected by the presence and accumulation of dust are those of the warp stop device 1 2 and the set 4 of heald frames; the dust P which forms in these zones remains trapped in the mechanical components or on the warp yarns until, growing in size, it acquires a weight sufficient to make it fall downwards. In an arrangement of this type, i.e. extending .n the vertical direction, the dust and the fluff fall onto parts of the loom located under the said dust forming zones, i.e. onto the warp beams 2. The dust P, adhering to the warp yarns, would thus be conveyed back into the circuit, continuing to accumulate. The present invention, in an attempt to break this vicious circle of events at its origin and solve the problem of dust removal, envisages providing each loom with dust collection and removal lines which intervene precisely at the most critical points located underneath the warp stop device 1 2 and the sets of heald frames 4. As can be seen in Fig. 1 and, in greater detail, in Figs. 2 and 4, the dust collection and removal system consists of two dust collection and removal lines 13, located underneath the warp stop device 1 2, and a third dust collection and removal line 14, which is located centrally between the two opposite weaving lines and extends to underneath the sets of heald frames 4. We shall now analyse separately and in detail the two different types of dust collection and removal lines which form the three lines of the present invention. As can be seen from the drawings, in fact, two of said lines, i.e. those located underneath the warp stop devices 12, are identical and therefore only one of them will be described below. A first type of line 13 is therefore positioned immediately underneath the warp stop device 1 2, above the warp beam 2 and, in a first embodiment illustrated in Fig. 3A, comprises a collecting channel 13a, in which a blowing tube 13b is housed (Fig. 2). The collecting channel 13a has a V or U-shaped cross-section, which is open upwards and sufficiently wide to embrace the entire area affected by the dust dropping from the overlying warp stop device 12. The blowing tube 13b is housed inside the collecting channel 13a, extending longitudinally over most of the length of the collecting channel itself, and has a series of holes 1 5 on its surface, from where compressed air, introduced at one end of the tube itself, emerges. These holes 1 5 are formed inclined with respect to the longitudinal axis of the tube 1 3b, as can be seen in Fig. 3, so as to impart to the compressed air a direction with a predetermined longitudinal component which serves to push the dust, collected inside the channel 13a, towards one of the two ends of the channel itself. Alternatively, the holes 15 may consist of suitably oriented nozzles. In a second embodiment, illustrated in Figs. 3B and 3C, the tube 13b is located outside the collecting channel 13a and directional nozzles 16 emerge from said tube, penetrating into the bottom part of the channel 13a, with an alternately right-hand and left-hand orientation, as can be seen in Fig. 3C. Therefore, the dust which, being dislodged from the warp stop device 12 falls into the collecting channel 13a, is pushed by the compressed air which emerges from the holes 1 5 or from the nozzles 1 6 towards one end of the channel itself; here, via a suction duct (not shown) the dust is removed from the channel 13a and conveyed into a bag or collection container (not shown) which are positioned in the vicinity of the loom. This last operation, which per se is already known, occurs in a completely automatic and continuous manner, it being necessary to intervene only periodically in order to empty the dust collection containers. A second type of line 14 is positioned at the centre of the loom, underneath the heald frames zone, and consists of a series of collecting trays 14a - facing the weaving lines and extending as far as the zone underneath sets of heald frames 4 - from where there departs a corresponding number of suction ducts 14b which converge into a suction selector 14c (Fig. 4). The suction selector 14c has the function of connecting one at a time, in succession, the individual ducts 14b to a single suction pipe 14d. The intermittent connection of the ducts 14a to the suction pipe 14d is performed by means of the selector 14c, following procedures already known per se in the so-called scanning valves, and allows a considerable saving in the amount of suction energy, while maintaining a high suction force for each collecting tray 14a. In fact, the dust which is dislodged from the set of heald frames 4 falls onto the underlying trays 14a, accumulating inside them fairly slowly. It is therefore not necessary to maintain a continuous suction action for all the trays 14a since it would not be justified in view of the small quantity of dust which falls thereon per unit of time. Instead, it is sufficient to remove the dust from the trays 14a at intervals of time of the order of magnitude of a few minutes, with a certain variability depending on the article and the speed of the loom, and hence concentrating in a rotational manner the suction power on each individual tray. The dust sucked into the duct of the tray concerned, will be sucked into the selector 14c and then into the pipe 14d so as to then be collected inside a container. In order to obtain a good sucking action, it is desirable if the collecting trays 14a are not excessively large in size, and hence the greater the extension of the loom the greater must be the number of trays aligned underneath the set of heald frames. In the embodiment shown in Fig. 4, the collecting trays are six in number, three for each weaving line, but it is perfectly possible to use a greater number of trays; for example, in looms for sheets (height of cloth equal to about 3.40 m) there are 1 6 collecting trays present - eight for each weaving line. The dust collected by the cleaning system according to the present invention may, as mentioned above, be accumulated inside individual containers arranged in the vicinity of each loom. Alternatively and preferably it is possible to centralize the collection of the dust in a single container for the entire weaving room, by connecting up the collecting devices of the individual looms. In this case, management of the distribution of the suction action inside the individual looms and in the various main ducts in the room may be advantageously performed by a central processing unit. A first major advantage of this structure arises from the possibility of concentrating the suction force in limited zones - corresponding to the extension of the individual collecting trays - so as to achieve more efficient removal of the dust, for the same power used. Another advantage is obtained from the extreme compactness of the second type of line 14 which, converging centrally, occupies a restricted space, otherwise unused in the double-beam vertical loom; moreover, the adoption of the selector 14c allows the use of a single suction pipe 14d and a single suction system which serves both the weaving lines of the double-beam vertical loom. The same comments are applicable to the two lines 13 of the first type, seeing that the two blowing tubes 13b may also be connected, with alternating operation, to the same air delivery point. In any case, the overall dust removal system according to the present invention fully achieves the aims set. First of all, it manages to remove perfectly the tufts of dust from the zones affected by this problem, eliminating any possibility of the vicious circle of dust accumulation being repeated. Moreover, it allows a considerable saving in energy compared to conventional suction systems, since its action is concentrated on specific working zones of the loom, thus avoiding acting in a global manner on the entire loom and wasting energy unnecessarily. It will be noted also that, by avoiding the indiscriminate blowing of jets of air onto the loom, the transfer of the dust produced on the loom into the environment is totally avoided. Finally, the use of compressed air in small quantities allows dry air to be used, avoiding use of the moist ambient air which gives rise to the problems mentioned above. It will be understood, therefore, that this system will be particularly advantageous precisely in those double-beam vertical looms which already have a pneumatic system used specifically for weaving where conveying of the weft is performed with air. Obviously, there is nothing to prevent the dust cleaning system described and illustrated above from being used also in single-beam vertical looms, as also in horizontal looms, by suitably adapting the number and form of the various parts which make up the system, and achieving also in these applications the same advantages indicated above. It is understood in any case that the invention is not limited to the particular configuration illustrated above, which forms only one non- limiting example thereof, but that numerous variants are possible, all of which within the grasp of a person skilled in the art, without thereby departing from the scope of the invention itself, as defined in the claims indicated below.

Claims: Claims 1 . System for collecting and removing dust, in a weaving loom of the type comprising at least one warp beam (2), at least one weaving line and at least one cloth beam (8), said weaving line comprising a warp stop device (12), a set of heald frames (4) and a reed (5), characterized in that it consists of at least two lines (13, 14) for collecting and removing the dust which forms during the weaving operations, at least one of said lines (13) being arranged underneath said warp stop device ( 12) and another of said lines (14) being arranged underneath the set of heald frames (4). 2. System for collecting and removing dust as claimed in claim 1 , in a double-beam vertical weaving loom of the type comprising two warp beams (2), two weaving lines and two cloth beams (8) which are all arranged opposite each other, characterized in that it comprises three lines (13, 14) for collecting and removing the dust which forms during the weaving operations, two of said lines (13), which are identical, being respectively arranged underneath the warp stop devices (12) of said opposite weaving lines and the third of said lines (14) being arranged in the central part of the loom underneath the two sets of heald frames (4) of said weaving lines. 3. System as claimed in claim 1 or 2, wherein each of said lines (13) for collecting and removing the dust arranged underneath the warp stop device consists of dust collecting means (13a) and dust conveying means (13b, 15,16). 4. System as claimed in claim 3, wherein said dust collecting means (13a) consist of a channel with a V- or U-shaped section and said dust conveying means consist of a compressed-air tube ( 13b) with a plurality of air outlets (15,16) acting inside the groove of said V-shaped section or on the bottom of said U-shaped section and oriented towards an outlet end of said channel. 5. System as claimed in claim 4, wherein said compressed-air tube (13b) is located inside said channel. 6. System as claimed in claim 4, wherein said compressed-air tube (13b) is located outside said channel. 7. System as claimed in claim 4, wherein said air outlets are in the form of holes (15) formed in the thickness of said compressed-air tube (13b). 8. System as claimed in claim 4, wherein said air outlets consist of nozzles (16) connected to said compressed-air tube (13b). 9. System as claimed in claim 1 or 2, wherein said dust for collection and removal line (14) the dust arranged underneath the heald frames (4) consists of a plurality of collecting and suction elements ( 14a, 14b) connected, through selector means ( 14c), to a single dust suction duct (14d). 10. System as claimed in claim 2, wherein said dust collection and removal line (14) arranged underneath the heald frames (4) consists of a plurality of collecting and suction elements in the form of collecting trays (14a) arranged alongside each other so as to form two opposite rows located underneath the heald frames (4), each tray (14a) being tapered towards the central part of the loom and connected there, through individual ducts (14b) and selector means (14c), to a single dust suction duct (14d). 1 1 . System as claimed in claim 9 or 10, wherein said selector means (14c) is a scanning valve.

Inventors: GENDELMAN MIKHAIL, GENDELMAN, MIKHAIL
Applicants: GENDELMAN MIKHAIL, SOMET SOC MEC TESSILE, GENDELMAN, MIKHAIL, SOMET SOCIETA' MECCANICA TESSILE S.P.A.
Application year: 1996
Main classification: D03J1
IPC codes: D03J1