Title of Invention

METHOD AND DEVICE FOR REMOVING FOREIGN MATTERS FROM A FIBRE MATERIAL, IN PARTICULAR FROM RAW COTTON

Abstract

A sensor system. (3, 3') for detecting foreign matters and a separation device (4) provided with at least one compressed air nozzle (5) which is perpendicular to a pneumatic fibre conveying conduit are successively mounted in a direction of conveyance (a), wherein said fibre conveying conduit is provided with a removing opening (6) arranged in front of the compressed air nozzle. Contrary to state of the art of actual methods and devices, the foreign matters are not removed to a substantially pressure-tight separation container. According to said invention, the removing opening (6) is connected to a derivation (7, 10) in which a permanent airflow (d, e) for transporting separated foreign matters away is maintained.

Full Text

Method and device for removing foreign matters from a fibre material, in particular from raw cotton The invention relates to a method for removing foreign matters in fibrous materials, in particular in raw cotton, according to the preamble of claim 1. Methods of this type are used, for example, in cleaning shops in order to prepare the raw cotton for the spinning process. In this case, at the earliest possible time after the bales of cotton have been opened, foreign fibres, such as strings, jute shreds and so on, but also plastic films and the like are removed. While in earlier times the contaminated portion was diverted into a removal container via a deflection flap or di-verter, nowadays the removal is carried out exclusively via a compressed air pulse directed transversely with respect to the fibre transport conduit. One problem with the known methods is that, as a result of the compressed air pulse, at the instant of the removal a large quantity of air is blown into the removal container during a short time interval. Here, there is a risk that the foreign matters already in the removal container will be swirled up as a result of the powerful turbulence produced and in this way can get into the fibre transport conduit again. Various attempts have already been made to solve the problem of the reverse flow and the reliable removal of the foreign matters. As early as in WO 89/01832, reference is made to the problem of the turbulence in the removal container which, there, is constructed so as to be largely pressure-tight with respect to the atmosphere. In order to avoid swirling, it is proposed to construct the removal container to be large, in such a way that it is able to break down the flows and turbulence triggered by the gas pressure pulse without impairing the material flow. The foreign matters can then be removed via airlocks at the bottom of the removal container. However, the problem cannot be. solved satisfactorily thereby and, given the restricted space in a cleaning shop, it is not desirable to build in large volume components unless absolutely necessary. In DE-U 296 04 552 it is proposed to deflect the air flow triggered by the compressed air pulse and to feed it back to the fibre transport conduit again. For this purpose, at a distance from the removal opening there is arranged a further opening, which connects the removal container permanently to the fibre transport conduit. Here, too, the removal container is sealed off in an airtight manner with respect to the atmosphere and it is not possible to see in detail how the foreign matters can be led away from the removal container. However, feeding back the flow into the fibre transport conduit does not readily effect reliable discharge of the foreign matters. In particular in the case of selective blowing out of contaminants over only part of the duct width, the air expelled will flow back into the transport duct via the nearest path, specifically via the removal opening. In EP-A 989 214, in order to solve the problem, it is proposed, at least during the duration of the removal pulse, either to enlarge the volume of the removal container or to extract air via an air extraction opening on the removal container. By doing this, although it is largely possible to prevent foreign matters flowing back into the fibre transport conduit, since the air present in the removal container does not need to be expelled by the compressed air pulse, the suction action at the instant of the removal nevertheless causes a disruptive movement of the foreign matters lying in the removal container and these still have to be removed from the removal container from time to time via airlocks. It is therefore an object of the invention to provide a method of the type mentioned at the beginning in which the foreign matters are removed reliably and continuously from the fibre transport conduit. In this case, the flow conditions in the fibre transport conduit should not be impaired, if possible, and the disposal of the foreign matters should be made possible without great effort. In addition, the method should permit adaptation to the given pneumatic transport conditions in a spinning factory in a relatively straightforward way. According to the invention, this object is achieved with a method which has the features in claim 1. As opposed to all previously proposed solutions, it has surprisingly been shown that the foreign matters removed do not necessarily have to be removed into a largely pressure-tight removal container. The removal according to the invention into a discharge conduit which is connected to the removal opening and in which a permanent air flow is maintained combines two advantages with each other. Firstly, the disposal of the foreign matters is carried out permanently and without intermediate storage in a removal container and, secondly, no reverse flow is triggered by the removal pulse. Given correct adjustment of the flow conditions, .no impermissible pressure drop in the fibre transport conduit is produced by the direct connection of the fibre transport conduit to the discharge conduit. The air flow in the discharge conduit is preferably adjusted in such a way that, when the removal device is inactive, a slight into the fibre transport conduit. This prevents, for example, dust and fine individual fibres getting into the discharge conduit continuously from the fibre transport conduit. The air flow in the discharge conduit can be maintained by sucking in atmospheric air, at least a partial flow prevailing, which runs away from the removal opening in the direction of the flow of the removal pulse. This flow is reached by a foreign substance only under the action of the removal pulse, a reverse flow no longer being possible in relative terms after the removal pulse has concluded. The permanent flow prevailing in the discharge conduit can in this case run in various directions relative to the flow of the removal pulse. An inadvertent reverse flow of foreign matters into the fibre transport conduit can further be prevented by the flow of the removal pulse being supplied with the aid of a guide element approximately tangentially to an extraction flow, which runs approximately transversely with respect to the flow of the removal pulse. Under the action of this guide element, a foreign substance assumes a course which is approximately helical, for example, reverse flow being reliably prevented. In relation to the width of the fibre transport conduit and the removal opening, the removal can be carried out selectively by means of a compressed air pulse only in that section in which the sensor system has detected a foreign substance. In addition, in the event of simultaneous actuation of a plurality of compressed air nozzles in various sections, no turbulence is produced which effects reverse flow of the foreign matters. The invention also relates to a device for removing foreign matters in fibrous material having the features of claim 6. The foreign matters removed by the device can be disposed of by the discharge conduit being connected to a waste container or a waste sack. The latter can be replaced from time to time. Alternatively, the discharge conduit could, however, also be connected directly to a disposal device which disposes of the foreign matters continuously. However, it would also be conceivable for the discharge conduit to be open with respect to the atmosphere and for the foreign matters to fall into an open container. For maintenance work on the device or, for example, for the replacement of waste containers, it could be advantageous to incorporate a slide with which the discharge conduit can be isolated temporarily from the removal opening. Further advantages and individual features of the invention emerge from the following description of exemplary embodiments and from the drawings, in which: Figure 1 shows a highly simplified perspective illustration of a removal device, Figure 2 shows the device according to figure 1 in a perspective overall illustration, Figure 3 shows a cross section through the discharge conduit in figures 1 and 2, and Figure 4 shows a schematic illustration of a further exemplary embodiment of the invention. As can be seen from figures 1 and 2, a device designated overall by 1 has a fibre transport conduit 2, in which cotton fibres or cotton flocks are transported in loose form. The device is integrated in a manner known per se into a cleaning line and, for example, is arranged after a bale removal machine or after a first coarse cleaner. The pneumatic transport means are known to those skilled in the art and not specifically illustrated here. In the present exemplary embodiment, the cotton fibres are led past the sensor system and the removal device from bottom to top with an inclination with respect to the vertical. However, this direction could be changed as desired. In the region of the detection of foreign matters and the removal, the fibre transport conduit 2 has a rectangular cross section, which subsequently merges again into a circular or any other desired cross section. In a known way, the sensor system comprises two cameras, for example CCD cameras 3, 3', whose optical axes are aimed at the fibre transport conduit from both sides via deflection mirrors 13, 13'. In the region in which the cameras act, the fibre transport conduit is transparent and illumination is carried out by means of lamps 14 illustrated only schematically here. Alternatively or in addition to the cameras 3, 3', the sensor system could also further have sensors which are able to detect a foreign substance with other physical parameters, such as ultrasonic sensors or sensors which react to electromagnetic field changes. In the direction of the transport flow a, after the action of the sensor system, a removal device designated overall by 4 is arranged on the fibre transport conduit 2. Said removal device has on one side a plurality of compressed air nozzles 5, which can be driven selectively, depending on the section in which the sensor system has detected a foreign substance. Arranged in the wall of the fibre transport conduit opposite the compressed air nozzles 5 is a removal opening 6, through which a foreign substance can be removed by means of a removal pulse b. This re- moval opening is connected via a connecting duct 10 to an extraction duct 7 running transversely with respect to the fibre transport conduit 2. Connecting duct and extraction duct overall form a discharge conduit for the foreign substance removed. The connecting duct 10 likewise has an approximately rectangular cross section of the same width as the removal opening 6. The connecting duct in this case leads tangentially into the extraction duct 7, which can be seen in particular from figure 3. Here, a curved guide plate 15 effects a configuration like a snail shell in the region of the junction. In addition, a suction slot 9, of which the cross section can be changed by means of an adjustable flow baffle 19 and which extends over the entire duct width, is provided above the connecting duct 10. Instead of the permanently set flow baffle, a sensor-controlled slide could also be provided, which controls the feed flow at the suction slot as a function of the pressure conditions. The suction slot 9 effects a flow e toward the extraction duct 7. The suction slot could also be arranged relatively close to the removal opening 6. An additional slot on the underside of the connecting duct 10 would also be conceivable. The extraction duct 7 running approximately horizontally is connected at one end to the suction side of a fan 8 and, from the latter, to a waste sack 12. Alternatively, the discharge conduit could also lead to a waste disposal system. The other end of the extraction duct 7 opens at the end of the housing 17 into a suction opening 11, the opening cross section of which can be adjusted in a similar way with a flow baffle. Viewing windows 18 could be provided for the observation of the processes in the extraction duct 7. The entire device rests on a frame 16 at a working height which makes the installation and the handling easier. During the installation of the device in the line, the flow conditions are adjusted with the aid of the aforementioned flow baffles in such a way that, in the region of the entry of the connecting duct 10 into the extraction duct 7, equilibrium in pressure terms virtually prevails between the transport flow a in the fibre transport conduit 2 and the extraction flow d in the extraction duct 7. The flow is advantageously set in such a way that, starting from the suction slot 9, a slight reverse flow c in the direction of the removal opening 6 also still prevails . As soon as the sensor system 3, 3' detects a foreign substance, the compressed air nozzle 5 in the appropriate section is activated, an intensive removal flow b being built up for a short time transversely with respect to the transport flow a. This removal flow drags a foreign substance 20 into the connecting duct 10 (figure 3), so that said foreign substance 20 is fed to the flow e and is transferred by the latter into the suction flow in the discharge conduit. In the process, the foreign substance passes under the curved guide plate 15 and, as can be seen, can then also no longer flow back into the connecting duct 10 if the removal flow b has discontinued. The foreign substance now remains in the extraction flow d and is disposed of immediately. The diameter of the extraction duct 7 could enlarge, starting from the suction opening 11, in order to cre-ate identical pressure relationships over the entire width of the connecting duct or in order to compensate for a resultant pressure drop. In the alternative exemplary embodiment according to figure 4, the flow a in the pneumatic transport conduit 2 runs from top to bottom. The connecting duct 10, starting from the removal opening 6, does not open into an extraction duct running transversely with respect thereto but merges directly with a slight curve into the extraction duct 7, which then tapers in cross section again to form a pipe, in which a conveyor fan 8 is arranged. As can be seen, here only a single suction opening is provided in the form of a suction slot 9. Its suction cross section could likewise be adjustable. Patent claims 1. A method for removing foreign matters in fibrous materials, in particular in raw cotton, the fibrous materials being led successively past a sensor system (3) and a removal device (4) in a pneumatic fibre transport conduit (1) and, when foreign matters are detected by the sensor system, these being removed from the fibre transport conduit through a removal opening (6) in the latter by means of a compressed air pulse oriented transversely with respect to the fibre transport conduit, characterized in that the foreign matters are removed into a discharge conduit (7, 10) connected to the removal opening (6), a permanent air flow being maintained in the discharge conduit to transport the foreign matters away. 2. The method as claimed in claim 1, characterized in that the air flow in the discharge conduit (7) is adjusted in such -a way that, when the removal device is inactive, a slight partial flow (c) prevails continuously from the discharge conduit (7) into the fibre transport conduit (2). 3. The method as claimed in claim 1 or 2, characterized in that the air flow in the discharge conduit is maintained by sucking in atmospheric air, at least a flow (e) prevailing, which runs away from the removal opening (6) in the direction of the removal pulse. 4. The method as claimed in one of claims 1 to 3, characterized in that the flow of the removal pulse is supplied with the aid of a guide element (15) approximately tangentially to a further extraction flow running transversely with respect to this flow. 5. The method as claimed in one of claims 1 to 4, characterized in that, in relation to the width of the fibre transport conduit (2) and the removal opening (6), the removal is carried out selectively by means of a compressed air pulse only in that section in which the sensor system has detected a foreign substance. 6. A device for removing foreign matters in fibrous materials, in particular in raw cotton, having a pneumatic fibre transport conduit (2) on which, one after another in the transport direction, there are arranged a sensor system (3) for the detection of foreign matters and a removal device (4) having at least one compressed air nozzle (5) acting transversely with respect to the fibre transport conduit, the fibre transport conduit having a removal opening (6) opposite the compressed air nozzle, characterized in that the removal opening (6) is connected to a discharge conduit (7, 10), it being possible for a permanent air flow to be maintained in the discharge conduit to transport the removed foreign matters away. 7. The device as claimed in claim 6, characterized in that the air flow in the discharge conduit can be adjusted by means of adjustment means in such a way that, when the removal device is inactive, a slight partial flow (c) can be maintained continuously from the discharge conduit (7) into the fibre transport conduit (2). 8. The device as claimed in claim 6 or 7, characterized in that the discharge conduit (7) is connected to a suction device (8), it being possible for air to be sucked in from the atmosphere, at least to some extent, via a suction opening, preferably via a suction slot (9), in such a way that a flow (e) acting away from the removal opening in the direction of the removal pulse can be produced. The device as claimed in one of claims 6 to 8, characterized in that the discharge conduit has a connecting duct (10) following the removal opening (6) and an extraction duct (7) running transversely thereto. The device as claimed in claim 8 and claim 9, characterized in that the connecting duct (10) preferably enters the extraction duct (7) tangentially, and in that the suction opening (9) is arranged in the region of the entry. The device as claimed in claim 9 or 10, characterized in that, in the region of the entry of the connecting duct (10) into the extraction duct (7), there is arranged a guide element (15), which extends in the longitudinal direction of the extraction duct and which feeds the flow of the removal pulse approximately tangentially to a further extraction flow in the extraction duct and which prevents a reverse flow into the connecting duct. The device as claimed in one of claims 6 to 11, characterized in that the discharge conduit (7, 10) is connected to a suction device (8), it being possible for air to be sucked in from the atmosphere through preferably a plurality of suction openings (9,11), and in that the cross sections of the suction openings can be adjusted. The device as claimed in one of claims 6 to 12, characterized in that a plurality of compressed air nozzles that can be activated selectively are arranged on the fibre transport conduit (2). 14. The device as claimed in one of claims 6 to 13, character ized in that the discharge conduit (7, 10) is connected to a waste container or to a waste sack (12). 15. The device as claimed in one of claims 6 to 13, character ized in that the discharge conduit (7, 10) is connected to a disposal device.

Documents:

3259-CHENP-2007 CORRESPONDENCE OTHERS 24-10-2014.pdf

3259-CHENP-2007 DECLARATION 09-07-2014.pdf

3259-CHENP-2007 AMENDED CLAIMS 09-07-2014.pdf

3259-CHENP-2007 AMENDED PAGES OF SPECIFICATION 09-07-2014.pdf

3259-CHENP-2007 ASSIGNMENT 13-02-2014.pdf

3259-CHENP-2007 CORRESPONDENCE OTHERS 13-02-2014.pdf

3259-CHENP-2007 EXAMINATION REPORT REPLY RECEIVED 09-07-2014.pdf

3259-CHENP-2007 FORM-1 09-07-2014.pdf

3259-CHENP-2007 FORM-13 09-07-2014.pdf

3259-CHENP-2007 FORM-3 09-07-2014.pdf

3259-CHENP-2007 FORM-6 13-02-2014.pdf

3259-CHENP-2007 POWER OF ATTORNEY 24-10-2014.pdf

3259-CHENP-2007 POWER OF ATTORNEY 06-02-2014.pdf

3259-CHENP-2007 POWER OF ATTORNEY 09-07-2014.pdf

3259-CHENP-2007 CORRESPONDENCE OTHERS 06-02-2014.pdf

3259-chenp-2007-abstract.pdf

3259-chenp-2007-claims.pdf

3259-chenp-2007-correspondnece-others.pdf

3259-chenp-2007-description(complete).pdf

3259-chenp-2007-drawings.pdf

3259-chenp-2007-form 1.pdf

3259-chenp-2007-form 3.pdf

3259-chenp-2007-form 5.pdf

3259-chenp-2007-pct.pdf

3259-CHENP-2007-Petition for POR.pdf

3259-CHENP-2007-Petition for Verfied English tran.certificate.pdf