GB2465468A

GB2465468A - An apparatus for removing impurities from between textile fibres in a spinning room

Info

Publication number: GB2465468A
Application number: GB0920037A
Authority: GB
Inventors: Guido Engels; Konrad Temburg
Original assignee: Truetzschler GmbH and Co KG
Current assignee: Truetzschler GmbH and Co KG
Priority date: 2008-11-19
Filing date: 2009-11-16
Publication date: 2010-05-26
Anticipated expiration: 2029-11-16
Also published as: ITMI20091883A1; IT1396374B1; BRPI0904492A2; BRPI0904492B8; BRPI0904492B1; CH699940B1; CN101736450A; GB0920037D0; CH699940A2; GB2465468B; CN101736450B; DE102008058254A1

Abstract

An apparatus in a spinning room preparation, ginning or like installation for the detection and separation of foreign matter in or between fibre material, having a fibre transport duct 2 along which there are arranged a sensor system 7 for the detection of foreign matter and a separation device 13 having at least one compressed-air nozzle effective transversely with respect to the fibre transport duct, the fibre transport duct having opposite the compressed-air nozzle a first opening 17 which leads into a separation chamber 15 connected to .a waste-discharge device 18, the blast air from the at least one compressed-air nozzle is suppliable in a closed system from the separation chamber through a further opening 19 to the conveying air current again. In order to allow reliable segregation of the foreign matter from the fibre material stream, without adversely affecting the air balance, in a structurally simple way, the separation chamber 15 is integrally connected to the fibre transport duct 2 and the blast air, before being returned to the conveying air current, passes through a filter device 20.

Description

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Apparatus in a spinning room preparation, ginning or like installation for the detection and separation of foreign matter in or between fibre material, especially cotton The invention relates to an apparatus in a spinning room preparation, ginning or like installation for the detection and separation of foreign matter in or between fibre material, especially cotton.

In practice, it is an important requirement of foreign body separators both in spinning room preparation machines and in similar machines in the ginning process that the foreign bodies detected be reliably separated with as little loss of good fibres as possible.

In such foreign body separators, the material to be inspected, cotton or synthetic fibres, is conveyed pneumatically in a rectangular channel and guided past a detection sensor system, for example past camera systems, in a presentation chamber. That is followed by the separation of the detected foreign bodies, for example by means of a blower bar, into a waste chamber. Inside the blower bar there is arranged a row of blow-out valves which can be controlled selectively, both across the width and in terms of time response, by the detection device.

Important parameters for reliable separation are here the number of valves activated, the necessary delay time and the holding time.

The number of activated valves is determined by the possible cross-flow of the material from the point of detection to the point of separation. The delay time and the holding time is determined by the speed of the foreign bodies. In this case, in particular the different speed of the foreign bodies is responsible for the fact that the holding time often has to be kept long in order reliably to meet the foreign bodies flying past.

The need for a large number of activated valves for reliable separation and a long holding time also mean,

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however, a high loss of good fibres, which occurs because a large number of good fibres is conveyed into the waste chamber along with the actual foreign bodies.

In foreign body separators in accordance with the prior art, therefore, the distance between the detection device and the separation device is kept as small as possible in order to minimise the number of valves to be activated as well as the holding time and accordingly the loss of good fibres.

A second factor reducing separation efficiency is that a large number of valves and a long holding time result in a large amount of air being conveyed into the waste chamber, leading to an increase in pressure therein and thus in a back-flow of air into the feed channel.

There is a risk that foreign bodies that have already been separated will be carried into the feed channel again by the back-flowing air.

Devices having retaining systems made of sheet metal, pressure-equalising channels or intermittently operating flap systems are known. The latter have the aim of conveying the foreign bodies which have already been separated and which are located in the waste chamber out of the waste chamber. For that purpose, for example, a flap is opened in order to extract the material pneumatic-ally from the waste chamber. In order that no further good material is extracted from the feed channel into the waste chamber at the same time, however, a further flap leading to a fresh air supply is to be opened into the waste chamber. A considerable disadvantage of that solution is that for the period during which the waste chamber is being emptied the separation of further foreign bodies into the waste chamber is substantially prevented by the changed pressure conditions. In order that the time intervals between emptyings of the waste chamber can be kept long, the waste chamber is therefore made corres-pondingly large.

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A further known possibility is to subject the waste chamber to continuous extraction. In order that good fibre material from the feed channel is not also sucked into the waste chamber, however, it is necessary first to have a fresh air supply into the waste chamber and to adjust the amount of waste-disposal air to the pressure conditions in the feed channel, which is difficult in practice on account of the changing conditions and which inter alia can also limit the amounts of air that are possible in the feed channel.

Finally, a common feature of both above-mentioned methods is that the distance between the detection device and the separation device has to be kept small in order thus to ensure functioning.

Particularly in the case of machines in which, as a result of their use or their structure, it is not possible to select a short distance between detection and separation or in which difficult air conditions prevail, the above arrangements do not result in acceptable solutions because inter alia a large number of valves and a long holding time have to be chosen in order to strike the foreign bodies, and so a large number of foreign bodies that have already been separated are flushed back into the channel again.

In a known apparatus (EP 0 989 214 Al), the separa-tion container has means for the temporary controlled withdrawal of air from the separation container. For the controlled withdrawal of air, in the normal operating state the air-withdrawal aperture on the separation container is closed with a non-return flap. In addition, the air-withdrawal aperture leads to a return duct which connects the separation container to the fibre transport duct again. As an alternative, the connection of the return duct to an off-take is also provided. In order to remove air from the separation container when a pulse of compressed air is triggered at the compressed-air nozzle, an air conveyor or injector is operated. The latter is connected via a valve to a compressed-air line. The valve receives control signals from the control device, a sucking action in the direction of the arrow being achieved by opening of the valve. It would also be possible to use other suitable means, such as fans etc., for withdrawing air from the separation container; it may be necessary in individual cases also to effect controlled closure of the air-withdrawal aperture. That apparatus is complex in terms of equipment, especially as a result of the control device. A particular problem is that, in control terms, additional dependence upon a particular separating operation is required. Finally, the amount of air withdrawn has to be controlled exactly in order not to have an adverse effect on the air balance, which entails undesirable disruptions of operation.

It is an aim of the invention to provide a device of the kind described at the beginning which avoids or mitigates the mentioned disadvantages and which, in particular, is structurally simple and allows reliable segregation of the foreign matter from the fibre material stream without adversely affecting the air balance.

The invention provides an apparatus in a textile fibre processing installation for the detection and separation of foreign matter in or between fibre material, having: a fibre transport duct; a sensor system for the detection of foreign matter in the transport duct; downstream of the sensor system in the fibre transport direction, a separation device having at least one compressed-air nozzle arranged to be effective transversely with respect to the fibre transport duct; a first opening in the fibre transport duct opposite said at least one compressed-air nozzle; and a separation chamber with which said first opening is in communication, said separation chamber being connected to a waste-discharge device and being so arranged that at least some of the blast air from the at least one compressed-air nozzle is suppliable from the separation chamber through a further opening to the conveying air current again; wherein the separation chamber is integrally connected to the fibre transport duct and the blast air, before being returned to the conveying air current, passes through a filter device.

As a result of the blast air's being returned directly from the separation chamber to the conveying air current, a balance between the amount of air and the air pressure is achieved in an especially simple way. In contrast to the known device there are no complicated and fault-prone control devices which, in addition, have to be adjusted exactly. Because a filter device, for example a filter, screen or the like, through which only the return air but not the foreign bodies are able to pass, is arranged between the separation chamber and the fibre transport duct, separation of the foreign bodies is achieved and contamination of the conveying air current is avoided in a simple and reliable way. There is no need to adjust the amount of waste-disposal air. The apparatus according to the invention allows continuous operation and therefore a high degree of efficiency of the foreign body separation, with a low waste chamber height and large distances between the detection and separation devices.

Because the separation chamber is integrally connected to the fibre transport duct, a compact structure is obtained.

As a result, on the one hand space is saved and on the other hand a highly functional unit is obtained.

The separation chamber is advantageously a separation container or the like. Advantageously, the separation chamber is of substantially pressure-tight construction.

Advantageously, the separation chamber has an opening for

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air to flow out of the separation chamber.

The opening may be provided for compensating for the air blown into the separation chamber during the separating operation and/or for compensating for the pressure of the air blown into the separating chamber during the separating operation. Advantageously, the separation chamber is arranged as a direct short-circuit with the fibre transport duct. Advantageously, the separation chamber directly adjoins the fibre transport duct. Advantageously, the separation chamber and the fibre transport duct have a common wall. Advantageously, an opening having a filter device, for example a filter, screen or the like, is present in the common wall.

Advantageously, the opening having the filter device, for example filter, screen or the like, allows the passage of return air. Advantageously, the opening for the passage of the blast air is adjoined by a guide element (metal guide sheet) having an open end. Advantageously, the guide element is able to direct the blast air into the separation chamber. In one advantageous embodiment, the guide element has a curved shape adjacent to its open end.

In another advantageous embodiment, the guide element is of segment-like construction adjacent to its open end.

Advantageously, the guide element together with an opposite wall surface forms a channel or the like. In one embodiment the wall surface opposite the end region of the * guide element is curved. In another embodiment, the wall surface opposite the end region of the guide element is of segment-like construction. In one preferred embodiment the components at least one compressed-air nozzle (blower bar), fibre transport duct (feed channel), filter, screen or the like (pressure-equalising screen) and waste-discharge device (cellular wheel sluice) are arranged around the separation chamber (waste chamber) Advantageously, the guide element is in the form of a metal retaining sheet for the blast air being returned.

Advantageously, the blast air is able to impact on the wall surface located opposite the guide element.

Advantageously, the cellular wheel sluice is constructed so as to be continuously rotatable. Advantageously, the blast air entering the separation chamber through the opening is forced into an eddy or the like.

Advantageously, the separation chamber is connected to an exit duct. Advantageously, the separation chamber is associated with a sluice. Advantageously, between the separation chamber and the exit duct there is arranged a sluice, for example a cellular wheel sluice or the like.

Advantageously, the exit duct is connected to a suction device. Advantageously, at least some of the blast air is suppliable to the conveying air current again.

Advantageously, the sensor system is connected to the separation device by means of an evaluating device and a control means. Preferably, fibre flocks are feedable through the fibre transport duct in an air current.

Advantageously, the sensor system comprises an optical sensor system. Advantageously, the sensor system is associated with the fibre transport duct. Advantageously, the separation device is associated with the fibre transport duct. The filter device advantageously comprises a collecting screen that is so fine that foreign matter is unable to pass through. For example, the collecting screen may have a mesh size (fineness) of about from 0.1 to 0.3 mm. Advantageously, the collecting screen is made of high-grade steel. Advantageously, the collecting screen is attached to a perforated metal sheet.

The screen may instead be a wire fabric.

The arrangement of the invention may be incorporated into any spinning room preparation apparatus or ginning apparatus. For example, the apparatus may be arranged in a ginning installation; a bale opener; a cleaning apparatus, the arrangement of the invention being arranged downstream of a cleaning device; a carding machine, the apparatus of the invention being arranged upstream of the carding machine; and a foreign fibre separator, the apparatus of the invention being arranged downstream of the foreign fibre separator.

The transport duct may be arranged in any suitable orientation. In some advantageous embodiments, the channel is arranged vertically. In other advantageous embodiments the channel is arranged obliquely. Where the duct is vertical or inclined, the fibre material may be conveyed through the channel from top to bottom or from bottom to top. In some embodiments, the channel is arranged horizontally.

Advantageously, the conveying means is a fan, the pressure side of which is connected to the upper end of the presentation channel, that is, the portion of the duct in which the fibre material is examined. Advantageously, the apparatus is of modular construction and has at least one detector module (sensor module) and a separation module.

In one especially preferred embodiment, the components arranged in a waste chamber located at the point of separation, such as metal guide sheets, pressure-equalising screens and cellular wheel sluice, co-operate to the effect that the air set in motion by the blast pulse strikes the pressure-equalising screen connected to the feed channel as a result of an eddy and is able to pass into the feed channel again and the foreign bodies and good fibres carried along by the blast pulse are delivered to a continuously operating cellular wheel sluiceand are thus disposed of.

Advantageously, the separation chamber is connected directly to the fibre transport duct. In *certain embodiments, in the fibre transport duct the further opening is arranged downstream of the first opening. In other embodiments, in the fibre transport duct the further

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opening is arranged upstream of the first opening. If desired, in an apparatus comprising a high-speed opening roll, an optical sensor system is associated with the high-speed opening roll.

The invention also provides an apparatus in a spinning room preparation, ginning or like installation for the detection and separation of foreign matter in or between fibre material, especially cotton, having a fibre transport duct along which there are arranged, one after the other in the transport direction, a sensor. system for the detection of foreign matter and a separation device having at least one compressed-air nozzle (blast air) effective transversely with respect to the fibre transport duct, the fibre transport duct having opposite the compressed-air nozzle a first opening which leads into a separation chamber connected to a waste-discharge device and the blast air from the at least one compressed-air nozzle being suppliable in a closed system from the separation chamber through a further opening to the conveying air current again, in which the separation chamber is integrally connected to the fibre transport duct and the blast air, before being returned to the conveying air current, passes through a filter, screen or the like.

Certain embodiments of the invention are described, by way of illustration, in detail below with reference to the accompanying drawings, in which: Fig. 1 shows a first apparatus according to the invention on a foreign body. detection and separation device having a vertical transport channel; Fig. 2 shows the apparatus of Fig. 1 with the flow path of the diverted blast air current; -10 -Fig. 2a is a side view, in enlargement, of a portion of the apparatus of the invention shown in Figs. 1 arid 2; Fig. 3 is a diagrammatic side view, partly in section, of a ginning machine having an apparatus according to the invention, which is located in the connecting channel between the ginning machine and the bale press; Fig. 4 shows a further embodiment of the apparatus according to the invention downstream of a four-roll cleaning machine; Fig. 5 shows an embodiment of the apparatus according to the invention downstream of a one-roll cleaning machine; Fig. 6 shows another embodiment of the apparatus according to the invention at a horizontal transport channel, the second opening being arranged upstream of the first opening; Fig. 7 shows an embodiment of the apparatus according to the invention at a horizontal transport channel, the second opening being arranged downstream of the first opening; Fig. 8 is a plan view of a blow-out device having a plurality of blast nozzles arranged over its width; Fig. 9 is a block diagram of an electronic control and regulating device, to which two sensor systems and a blow-out device are connected

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-11 -and Fig. 10 shows an arrangement as in Fig. 6 in which an optical sensor system is associated with the upstream opening roll.

With reference to Fig. 1, a first embodiment of the invention is provided on a foreign body detection and separation device having a vertical transport channel in which fibre material is transported from top to bottom.

According to Fig. 1, a vertically arranged channel 2 is provided in a housing 1. The parallel side walls 2', 2' located opposite one another are constructed, at least in part, as transparent panes. Illumination means are associated with the outsides of both side walls 2', 2' A first detector device 3 comprises two CCD cameras 4', 4'' (line-scan cameras), which are indirectly applied to the glass channel 15 by way of two tilted mirrors 5' and 5'', respectively, arranged at an angle. The optical planes are arranged slightly offset from one another. On that side of the channel 2 which is located opposite the camera 4' there is arranged a lighting system 6' , and on that side of the channel 2 which is located opposite the camera 4'' there is arranged a lighting system 6'. By that means, the material in the glass channel 15 is detected by the two cameras 4', 4' from two sides.

The housing 1' containing the glass channel 15, the cameras 4', 4' , the tilted mirrors 5', 5' and the lighting systems 6t, 6'' forms a first detection module 7', where, especially, coloured foreign material in and between the cotton is detected.

Below the first detection module 7' there is a second detection module 7''. The cross-sections of the channel 2 are the same.

A second detector device 8 comprises a CCD camera 9, which is indirectly applied to the glass channel 16 by way

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-12 -of a tilted mirror 10 arranged at an angle. On that side of the channel 2 which faces away from the camera 9 there is arranged a lighting arrangement 11 having polarisation filters (see Fig. 2), and on that side of the channel 2 which faces the camera 9 there is arranged a lighting system 12 for UV light. The polarised light (transmitted light) and the reflected light due to UV irradiation (incident light) are jointly captured by the one CCD camera 9. Light -transmitted light and incident light -is applied to the material in the glass channel 16 from two sides.

The housing 1'' containing the glass channel 16, the camera 9, the tilted mirror 10 and the lighting arrangements 11, 12 forms a second detection module 7'', where, especially, light-coloured or transparent plastics in or between cotton are detected.

Below the second detection module 7' there is provided a separation module 13. The separation module 13 in the housing 1' comprises a row of nozzles 14, which is associated with a side wall of the channel 2. Associated with that side wall of the channel 2 which is located opposite the row of nozzles 14 (see Fig. 7) is a collection container 15, which is under suction, for the impurities blown out from the conveyed stream.

The wall of the fibre transport duct 2 has opposite the row of nozzles 14, which is effective transversely with respect to the fibre transport duct 2, a first opening 17 which leads to the separation chamber 15 which is connected to a cellular wheel sluice 18 as discharge device. The blast air B from the row of nozzles 14 is in a closed system suppliable to the conveying air current A again from the separation chamber 15 through a further opening 19 in the wall of the fibre transport duct 2. The further opening 19, which is arranged downstream of the first opening 17, is closed by a screen 20 which allows the passage only of the returning blast air B. In that

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-13 -way, the separation chamber 15 is integrally connected to the fibre transport duct 2.

The blast air, which is discharged at high speed from the nozzles of the row of nozzles 14, enters the interior of the fibre transport duct 2 through an opening (not shown) in the wall of the fibre transport duct 2 and leaves the interior of the fibre transport duct 2 through the first opening 17.

Fig. 2 shows an arrangement as in Fig. 1 in which the components blower bar 14, feed channel 2, pressure-equalising screen 20 and cellular wheel sluice 18 are arranged around the waste chamber 15. One illustrative arrangement suitable for use as a blower bar 14 is described below with reference to Fig. 8.

The pressure pulse(s) triggered by the valves arranged in the blower bar 14 convey(s) the foreign bodies and the entrained good fibres into the waste chamber 15.

By virtue of the configuration of the waste chamber 15, the air flowing therewith is forced into an eddy C in the rear region of the waste chamber 15, so that the air that has been set in motion impacts directly on the pressure-equalising screen 20 arranged at the chute wall of the feed channel 2 and there passes into the channel 2 again.

In addition, a metal retaining sheet 21 prevents the air from being able to pass upwards back into the channel 2 again, so that there is no risk that foreign bodies will be flushed back into the feed channel 2 again. The foreign bodies entrained by the pressure pulse and the air flowing therewith into the waste chamber 15 as well as the good fibre material either strike the obliquely arranged forward boundary 15a of the waste chamber 15 and slide into the cellular wheel sluice 18 or are delivered directly to the cellular wheel sluice 18 in the lower portion of the eddy C as a result of gravity. The cellular wheel sluice 18 rotates continuously (arrow 18a) and conveys the separated material into the waste extraction -14 -means 22 and thus results in a separation, in pneumatic terms, of the waste-disposal air from the conveying air in the channel 2, so that they do not need to be matched to one another.

Reference numeral 23 indicates a channel-like entrance into the waste chamber 15. The retaining element 21 is in the form of a guide element for the blast air current B and has an end open at one side. Adjacent to the open end, the guide element 21, for example a metal sheet, is of segment-like (or curved) construction and forms a wall surface of the channel entrance 23. Opposite the segment-like (or curved) end region of the guide element 21, the wall surface 15a of the waste chamber 15 is likewise of segment-like (or curved) construction. In that way, the blast air current B entering the waste chamber 15 is forced into a curve to form an eddy C which flows in the direction of the second opening 19 or the screen 20. Reference numerals 15b and l5c indicate the wall surfaces of the waste chamber 15 which taper conically in the direction of the cellular wheel sluice 18.

In the apparatus of Fig. 3, a ginning machine 45 in a ginning installation is connected, via a channel 46, to a bale press 47. Under the action of compressed air, the mixture of freed cotton fibres and seeds and the like passes from the ginning machine 45 into the channel section 46a. By way of the apparatus 48 for separating out waste matter (trash, sand and the like) from the cotton fibres, the cleaned cotton fibres pass by way of the channel section 46b into the channel 49 of the bale press 47. Arranged in the vertical channel section 46b is a second embodiment of the apparatus according to the invention, consisting of -seen in the direction of material flow -a second detection module 7' (for plastics-fibre foreign bodies), a first detection module 7' (for coloured foreign bodies) and a separation module -15 - 13. (The arrangement corresponds to the construction shown in Figure 4 for a cleaning machine.) In the apparatus of Fig. 4, an apparatus according to the invention is mounted downstream of a cleaning machine 50, for example a cleaning machine CL-C4 made by Trützschler GmbH & Co. KG of Mônchengladbach, Germany. The fibre material is removed from the last high-speed clothed roller 514 by an air current E (air doffing) and passes as a fibre-air flow A into a channel 52, which is of approximately U-shaped construction, one arm of which merges upwards into a vertical channel 53. The fibre-air mixture A flows through the channel 53 from bottom to top.

The apparatus according to the invention, consisting of -seen in the material flow direction A -a second detection module 7'' (for plastics foreign bodies) , a first detection module 7' (for coloured foreign bodies) and a separation module 13 (comprising a blow-out device 14, a suction off-take and a return means for blast air), is associated with the channel 53. The fibre-air mixture A freed from foreign bodies is subsequently fed onwards for further processing.

In the arrangement of Fig. 5, an embodiment of the apparatus according to the invention is mounted downstream of a cleaning machine 54, for example a cleaning machine CL-Cl made by TrQtzschler GmbH & Co. KG. The fibre material is removed from the high-speed clothed roller 55 by the air current E (air doffing) and p'asses as a fibre-air flow A into an obliquely arranged channel 56, which merges upwards via a curved region into a vertical channel 53. The fibre material A flows through the channel 56 and the channel 53 from bottom to top. The apparatus according to the invention is associated with the channel 53. In contrast to the construction according to Fig. 4, there are -seen in the material flow direction A -associated first of all a first detection module 7' and then a second detection module 7'', which is followed by the separation -16 -module 13.

In the arrangement of Fig. 6, the upper inlet opening of a feed chute 60 has associated with it an arrangement for the pneumatic supply of a fibre-air flow H, which comprises a fibre material transport fan (not shown), a stationary air-permeable surface 61 for segregation (separation) of the fibre material I from air K with air extraction, and an air flow guide means 62 with movable e1ements the fibre material present in the air flow is guided reversibly backwards and forwards transversely over the air-permeable surface 61 and, following impact, the fibre material falls substantially as a result of gravity from the air-permeable surface 61 and enters the feed chute 60 downwards. The slow-speed rollers 63a, 63b have a dual function: they serve as take-off rolls for the fibre material I out of the feed chute 60 and at the same time as feed rolls for supplying the fibre material I to a high-speed opening roll 64. The solid arrows represent fibre material, the empty arrows represent air and the half-filled arrows represent an air current with fibres.

A blast air current E flows through a channel approximately tangentially to the opening roll 64, detaches the fibre covering (good fibres) from the clothing and flows away as a fibre-air flow A through a fibre transport duct 37 through two glass channels arranged one after the other in the horizontal region of the fibre transport duct 37 and not directly after the opening roll 64.

The apparatus according to the invention is associated with the pneumatic fibre transport duct 37. The apparatus is suitable for detecting and separating foreign matter of any kind, for example pieces of cloth, tapes, string, pieces of sheeting etc, in the fibre material. Seen in the material flow direction, there are provided first of all a first detection module 7' and then a second detection module 7'', which is followed by the separation module 13.

-17 -The detection module 7' serves for the detection of foreign matter, especially having brightness and/or colour variations. The optical system with the cameras 4', 4' (only 4' shown) is arranged above the channel 37 and to the side of the feed chute 60. This produces a compact, space-saving construction. The colour line-scan cameras 41, 41 I are directed towards the glass channel 15 and are able to detect coloured foreign matter, for example red fibres, in the fibre material. The cameras cover the entire region across the width of the channel 37. The downstream detection system 7' serves for the detection of foreign bodies made of plastics, such as polypropylene tapes, fabrics and films and the like, in or between fibre flocks, for example of cotton and/or synthetic fibres. The plastics are light-coloured, white or transparent.

Arranged above the fibre transport duct 37 across the machine width, which is, for example, 1600 mm, in a housing, are two cameras 9', 9'', e.g. diode line-scan cameras with polarisation filters. Beneath the cameras 9', 9'' (only camera 9' is shown), the wall surfaces of the fibre transport duct 37 have two transparent regions in the form of two parallel and opposite glass panes (glass windows), which form a glass channel 16. As a source of polarised light, a lighting arrangement 11 is provided beneath the fibre transport duct 37. As a source of ultraviolet (UV) light, a further lighting arrangement 12 is provided above the fibre transport duct 37. Downstream of the detection system 7' there is arranged a separation module 13 having a row of nozzles 14 (blow-out device) for producing a blast air current, the nozzles of which are so oriented in the direction of the channel 37 that a short sharp jet of air flows approximately perpendicular in relation to the channel 37. The first detector device and the further detector device are connected, by way of an evaluating device and an electronic control and regulating device 71 (see Fig. 9), to the blow-out device, with which -18 -there is associated a valve control means (see Fig. 9) When the cameras have detected coloured or transparent foreign matter in the fibre material using comparative and desired values, a short air blast is emitted, using the valve control means, at high speed in relation to the channel 37, expelling the foreign matter with a few fibres out of the fibre stream A by a blast air current and subsequently carrying them away through a channel which is under suction. After the blow-out device, the fibre-air stream A is sucked through the fibre transport duct 37 and fed onwards for further processing.

In the arrangement of Fig. 6, in the horizontal transport channel 37 the second opening 19 is arranged upstream of the first opening 17.

With reference to Fig. 7, in an alternative arrangement, in the horizontal transport channel 37 the second opening 19 having the screen 20 is arranged downstream of the first opening 17.

In an illustrative form of blow-out device shown in Fig. 8, the blow-out device 14 comprises a plurality of blast nozzles 67a to 67n, each associated with a respective valve 68a to 68n. The blast nozzles 67a to 67n are connected by way of the valves 68a to 68n to a common compressed-air line 69, which is connected to a source of compressed air 70. The reference numeral 2 denotes the fibre transport duct, which has inlet openings in its wall surface 2' for the blast nozzles 67a to 67n. The outlet opening 17 for the currents of blast air B into the collection container 15 is shown in Fig. 1. The valves 68a to 68n are selectively controlled by a valve control means, for example in the presence of foreign matter 23' the valve 68d is briefly opened so that a sharp current of air leaves the nozzle 67d at high speed, for example mach 1, for a short period (milliseconds) and blows the foreign body 23' into the collection container 15 (see Fig. 1), which is under suction.

-19 -In an illustrative arrangement shown in Fig. 9, the cameras 4, 9, an image-evaluating device 26 and a valve control means 73 for the valves 68a to 68n of the blow-out device 14 are connected to an electronic control and regulating device 71.

Fig. 10 shows an arrangement as in Fig. 6, but in which -instead of the detection module 7' arranged downstream of the opening roll 64 -an optical sensor system 74 is associated with the opening roll 64 itself. The sensor system 74 can be connected to the electronic control and regulating device 71 (Fig. 9). The entire surface of the opening roll 64 is associated with the optical sensor system 74, for example a line-scan camera (CCD camera) having an electronic evaluating device for the detection of foreign matter, especially having brightness and/or colour variations. The sensor system 74 with the camera, for example a colour line-scan camera, is arranged obliquely above the opening roll 64 close to the outer wall of the filling chute 60. This produces a compact, space-saving construction. The colour line-scan camera 74 is directed towards the clothing of the opening roll 64 and is able to detect coloured foreign matter, for example red fibres, in the fibre material. The camera 74 covers the entire region across the width of the opening roll 64, for example 1600 mm. The opening roll 64 rotates anti-clockwise in the direction of the curved arrow. The sensor system 74 is connected, by way of an evaluating device and an electronic control and regulating device 71, to the device 13, with which there is associated a valve control means 73. When the camera 74 has detected foreign matter in the fibre material on the clothing surface using comparative and desired values, a short air blast is emitted, using the valve control means 73, at high speed in the direction of the separation chamber 15, expelling the foreign matter 23' (see Fig. 8) with a few fibres out of the air current A, the foreign matter being removed by -20 -the cellular wheel sluice 18. The blast air current C is diverted in the separation chamber 15 and supplied to the conveying air current A again through the further opening 19.

In an apparatus according to the invention, air carrying foreign matter and fibre is blown out of a transport duct in which fibre material is being transported pneumatically, the removed air carrying the foreign matter and fibre passing into a separation chamber and at least a part of the air accompanying the removed foreign matter and fibre being recycled back into the transport duct via a return opening communicating between the separating chamber and the transport duct. A filter device is provided preferably in the opening, for filtering the air to be recycled in order that any foreign matter entrained therein is retained in the separation chamber. Preferably, the removed air and entrained foreign matter and fibre is expelled from the transport duct through an expulsion opening, the expulsion opening communicating between the transport duct and the separation chamber. In certain preferred embodiments, as described above, the expulsion opening and the return opening are provided in a common wall between the transport duct and the separation chamber. The expulsion opening may be in communication with the separation chamber directly or indirectly, for example, by means of a channel.

Claims

-21 -Claims 1. An apparatus in a textile fibre processing installation for the detection and separation of foreign matter in or between fibre material, having: a fibre transport duct; a sensor system for the detection of foreign matter in the transport duct; downstream of the sensor system in the fibre transport direction, a separation device having at least one compressed-air nozzle arranged to be effective transversely with respect to the fibre transport duct; a first opening in the fibre transport duct opposite said at least one compressed-air nozzle; and a separation chamber with which said first opening is in communication, said separation chamber being connected to a waste-discharge device and being so arranged that at least some of the blast air from the at least one compressed-air nozzle is suppliable from the separation chamber through a further opening to the conveying air current again, wherein the separation chamber is integrally connected to the fibre transport duct and the blast air, before being returned to the conveying air current, passes through a filter device.
2. An apparatus according to claim 1, in which the separation chamber is a separation container.
3. An apparatus according to claim 1 or claim 2, in which the separation chamber is of substantially pressure-tight construction.
4. An apparatus according to any one of claims 1 to 3, in which the separation chamber has a second opening for air to flow out of the separation chamber.
5. An apparatus according to claim 4, in which said second opening is provided for compensating for the air blown into the separation chamber during the separating operation.

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6. An apparatus according to claim 4 or claim 5, in which said second opening is provided for compensating for the pressure of the air blown into the separating chamber during the separating operation.
7. An apparatus according to any one of claims 4 to 6, in which the separation chamber is directly short-circuited with the fibre transport duct.
8. An apparatus according to any one of claims 4 to 7, in which the separation chamber is in directly abutting relationship with the fibre transport duct.
9. An apparatus according to any one of claims 4 to 8, in which the separation chamber and the fibre transport duct have a common wall.
10. An apparatus according to claim 9, in which said second opening is present in the common wall.
11. An apparatus according to claim 10, in which said second opening present in the common wall is provided with said filter device.
12. An apparatus according to claim 11, in which the opening having the filter device allows the passage of return air.
13. An apparatus according to claims 10 to 12, in which the common wall further comprises the first opening.
14. An apparatus according to any one of claims 4 to 13, in which in the fibre transport duct the second opening is arranged downstream of the first opening.
15. An apparatus according to any one of claims 4 to 13, in which in the fibre transport duct the second opening is arranged upsteam of the first opening.
16. An apparatus according to any one of claims 1 to 15, in which the first opening for the passage of the blast air is adjoined by a guide element having an open end.
17. An apparatus according to claim 16, in which the guide element is arranged to direct the blast air into the separation chamber.
18. An apparatus according to claim 16 or claim 17, inS-23 -which the guide element has a curved shape adjacent to its open end.
19. An apparatus according to claim 16 or claim 17, characterised in that the guide element is of segment-like construction adjacent to its open end.
20. An apparatus according to any one of claims 16 to 19, in which the guide element together with an opposite wall surface forms a channel.
21. An apparatus according to any one of claims 16 to 20, in which the wall surface opposite the end region of the guide element is curved.
22. An apparatus according to any one of claims 16 to 20, in which the wall surface opposite the end region of the guide element is of segment-like construction.
23. An apparatus according to any one of claims 16 to 22, in which the guide element is in the form of a screen for retaining the blast air being returned.
24. An apparatus according to any one of claims 16 to 23, in which the blast air is able to impact on the wall surface located opposite the guide element.
25. An apparatus according to any one of claims 1 to 24, in which there are arranged around the separation chamber at least one compressed-air nozzle, fibre transport duct, filter device and waste-discharge device.
26. An apparatus according to any one of claims 1 to 25, in which the blast air entering the separation chamber through the opening is forced into a perturbed flow.
27. An apparatus according to any one of claims 1 to 26, in which the separation chamber is connected to an exit duct.
28. An apparatus according to claim 27, in which between the separation chamber and the exit duct there is arranged a sluice.
29. An apparatus according to any one of claims 1 to 25, in which the sluice comprises a cellular wheel sluice that is constructed so as to be continuously rotatable.

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30. An apparatus according to any one of claims 27 to 29, in which the exit duct is connected to a suction device.
31. An apparatus according to any one of claims 1 to 30, in which a proportion of the blast air is suppliable to the conveying air current again.
32. An apparatus according to any one of claims 1 to 31, in which the sensor system is connected to the separation device by means of an evaluating device and a control means.
33. An apparatus according to any one of claims 1 to 32, in which fibre flocks are feedable through the fibre transport duct in an air current.
34. An apparatus according to any one of claims 1 to 33, in which the sensor system comprises an optical sensor system.
35. An apparatus according to any one of claims 1 to 34, in which the sensor system is. associated with the fibre transport duct.
36. An apparatus according to any one of claims 1 to 35, in which the separation device is associated with the fibre transport duct.
37. An apparatus according to any one of claims 1 to 33, in which the filter device has apertures of size so selected that foreign matter is unable to pass through.
38. An apparatus according to any one of claims 1 to 37, in which the filter device has a collecting screen of mesh size (fineness) of about from 0.1 to 0.3 mm.
39. An apparatus according to claim 37 or claim 38, in which the collecting screen is made of high-grade steel.
40. An apparatus according to any one of claims 1 to 39, in which the filter device comprises a collecting screen that is attached to a perforated metal sheet.
41. An apparatus according to claim 39 or claim 40, in which the screen is a wire fabric.
42. An apparatus according to any one of claims 1 to 41, in which the apparatus is arranged in a ginning -25 -installation.
43. An apparatus according to any one of claims 1 to 41, in which the apparatus is arranged downstream of a bale opener.
44. An apparatus according to any one of claims 1 to 41, in which the apparatus is arranged downstream of a cleaning device.
45. An apparatus according to any one of claims 1 to 41, in which the apparatus is arranged upstream of a carding machine.
46. An apparatus according to any one of claims 1 to 41, in which the apparatus is arranged downstream of a foreign fibre separator.
47. An apparatus according to any one of claims 1 to 46, in which the duct is arranged vertically.
48. An apparatus according to any one of claims 1 to 46, in which the duct is arranged in an inclined position.
49. An apparatus according to claim 47 or claim 48, in which the fibre material is conveyed through the duct from top to bottom.
50. An apparatus according to claim 47 or claim 48, in which the fibre material is conveyed through the duct from bottom to top.
51. An apparatus according to any one of claims 1 to 46, in which the duct is arranged horizontally.
52. An apparatus according to any one of claims 1 to 51, in which the conveying means is a fan, the pressure side of which is connected to the upper end of the fibre transport duct.
53. An apparatus according to anyone of claims 1 to 52, in which the apparatus is of modular construction and has at least one detector module and a separation module.
54. An apparatus according to any one of claims 1 to 53, in which components arranged in a waste chamber located at the point of separation, co-operate to the effect that the air set in motion by the blast pulse strikes a screen of -26 -the second opening connected to the feed channel as a result of being deflected and is able to pass into the feed channel again and the foreign bodies and good fibres carried along by the blast pulse are delivered to a continuously operating waste-discharge device and are thus disposed of.
55. An apparatus according to any one of claims 1 to 54, in which the separation chamber is connected directly to the fibre transport duct.
56. An apparatus according to any one of claims 1 to 55, in which the sensor system comprises an optical sensor system associated with a high-speed opening roll located upstream of the separation device.
57. An apparatus for the detection and separation of foreign matter in or between fibre material substantially as described herein with reference to and as illustrated by any of Figs. 1, 2 and 2a and 3 to 10.
58. A method of detecting and removing foreign matter in or between fibre material, comprising transporting the fibre material pneumatically in a fibre transport duct past a sensor device and subsequently past a separation device, detecting the foreign material by means of the sensor device, and operating the separation device in response to detection of foreign matter, wherein a portion of fibre material containing the foreign matter is blown by the separation device into a separation chamber opposite and air returns to the transport duct through a common wall portion of the transport duct and the separation chamber.
59. A method according to claim 58 in which the common wall portion comprises an element having a multiplicity of apertures through which the air passes, the foreign matter being retained in the separation chamber.