Carding machine and method for operating a carding machine

Abstract

The invention relates to a carding machine comprising a drum (4) and multiple fixed and circulating carding elements, which are designed to parallelise and clean fibres such that the resulting fibrous web is subsequently transferred to a doffer (5), wherein a spandrel profile (20) is arranged in the spandrel-like area between the drum (4) and the doffer (5). The invention is characterised in that a vacuum extraction hood (25) is arranged on the doffer (5) in the region of the spandrel-like area, which forms a gap together with the spandrel profile (20) such that an air flow (27) opposite the rotational direction of the doffer (5) can travel into a suction opening (25a) of the extraction hood (25).

Description

[0001] Title: Carding machine and method for operating a carding machine

[0002] Description

[0003] The present invention relates to a carding machine and a method for operating a carding machine according to the preamble of claims 1 and 10.

[0004] When processing opened fiber flakes, the fibers are parallelized and cleaned in the card between a cylinder equipped with a full-metal clothing and rotating flat clothings. The use of suction hoods is well known in this area, from the licker-in to the drum. A doffer roller arranged behind the cylinder in the fiber transport direction takes the fiber web from the cylinder and guides it via further rollers and a cross belt to a doffer hopper, which forms a fiber sliver from the fiber web. The doffer usually rotates against the direction of rotation of the drum, although the doffer has a lower speed than the drum. The clothing wound on the doffer is aligned with the tooth direction against the direction of rotation of the doffer.Due to the difference in speed and diameter between the drum and doffer, the doffer has a much lower peripheral speed than the drum, so that the carded fiber web is compressed into the teeth of the doffer. The subsequent transfer of the fiber web to the doffer roller is therefore not complete because fibers remain stuck in the tooth base of the clothing. Over time and under unfavorable operating conditions, the doffer clothing can become clogged so that the fiber web is no longer completely taken over by the drum. This increases the drum loading, which reduces the productivity of the card. The fiber web is not completely taken over by the doffer, so that some of the fibers remain on the drum or in the drum clothing, creating thick spots.

[0005] The object of the invention is to further develop a carding machine in which the transfer of the fiber web from the drum to the doffer is improved, or a return flow of the fibers from the doffer to the drum is prevented.

[0006] This object is achieved starting from a carding machine according to the preamble of claim 1 and with the characterizing features. The object is also achieved by a method for operating a carding machine.

[0007] Advantageous developments of the invention are specified in the dependent claims.

[0008] The carding machine comprises a drum and several stationary and rotating carding elements designed to parallelize and clean fibers. The resulting carded fiber web is then transferred to a doffer, with a doffer profile arranged in the upper gusset between the drum and the doffer.

[0009] The invention is based on the idea that an air flow that is directed into the opening of an extraction hood against the direction of rotation of the collector causes the fibers to be completely sucked out of the teeth of the clothing. In particular, the orientation of the clothing teeth, whose tips are arranged against the direction of rotation, prevents complete removal of the fibers with conventional suction. The structural implementation is achieved by arranging an exhausted extraction hood on the collector in the area of ​​the upper gusset, whereby the outer contour of the extraction hood together with the gusset profile forms a gap through which an air flow can pass into an extraction opening in the extraction hood against the direction of rotation of the collector. Redirecting the air flow against the direction of rotation of the collector results in almost complete removal of the fibers from the tooth base of the collector's clothing.

[0010] The extraction hood can be arranged at an angle a of 20° - 40°, which is formed between the theoretical transfer point of the fiber web or the narrowest point between the drum and the doffer, and by a connecting line between the pivot point of the doffer and the geometric center of the extraction hood. Arranging the extraction hood as close as possible to the upper gusset promotes the guidance of the air flow, as the outer contour of the extraction hood can interact with the gusset profile and, if present, with a fixed carding element. Arranging it as close as possible to the upper gusset is also advantageous because accessibility to the drum and doffer is limited in this area, making other areas of the doffer easier to reach for maintenance and cleaning.

[0011] The gap for the air flow to be generated between the outer contour of the extraction hood and the gusset profile can have a gap size b of between 4 mm and 10 mm, preferably a gap size of between 6 mm and 8 mm. In conjunction with the suction or negative pressure in the extraction hood, these gap sizes are advantageous with regard to the amount of fresh air entering this area of ​​the card. A sufficient flow velocity can be generated without increasing the suction pressure. The gap size does not have to have a constant value, but can vary over the gap length within this specified range, whereby the existing structural components can be used without modification. The gap can be parallel across the working width, i.e. have a constant distance between the drum and the outer contour of the extraction hood. However, the gap can also have a varying distance, for example to the edge of the drum orThe outer contour of the extraction hood must be narrower than the center of the working width. The extraction opening of the extraction hood is located between a first and a second support surface and is aligned with the collector's clothing in the opposite direction to the collector's rotation. The air flow is guided along the surface of the collector's clothing and directed away from it in the area of ​​the extraction opening, so that the fibers are sucked out of the clothing's teeth.

[0012] The extraction opening can have an opening width c of 10 mm to 20 mm. Since the greatest suction effect occurs at the edge where the airflow enters the extraction opening, increasing the opening width would be counterproductive. The negative pressure present in the extraction hood would have to be increased. A smaller opening width would also worsen the results, as the airflow could become trapped.

[0013] A first support surface, located between the extraction opening and the gusset profile, has an edge positioned opposite to the direction of rotation of the doffer. This edge acts like a knife against the direction of rotation of the doffer and can thus effectively guide the fibers from the clothing into the extraction hood.

[0014] The air flow is directed from the gap between the outer contour of the extraction hood and the gusset profile under the first contact surface of the extraction hood into the extraction opening. The distance between the first contact surface and the clothing is smaller than the gap between the outer contour of the extraction hood and the gusset profile. This increases the flow velocity, which effectively extracts the fibers from the collector's clothing.

[0015] Because the first support surface is at a smaller distance from the pickup assembly than the second support surface, the drag air that is carried along with the pickup is stopped at the edge of the first support surface and sucked away by the generated air flow.

[0016] The second support surface is inclined at an acute angle in an area facing the extraction opening, increasing its distance from the pickup's assembly. This creates a suction effect on the assembly even before the corresponding part of the assembly is below the extraction opening. This ensures that the extraction function works even at high pickup speeds.

[0017] The inventive method for operating a carding machine with a drum provides for the subsequent transfer of carded fibers as a fiber web to a doffer. A doffer profile is arranged in the upper gusset between the drum and the doffer. Together with the outer contour of a suction hood, this creates a gap, creating an air flow within the carding machine. This air flow passes into a suction opening of the suction hood, counter to the direction of rotation of the doffer, thereby sucking fibers out of the doffer's clothing.

[0018] Because the air flow is guided between the outer contour of the extraction hood and the gusset profile and then flows between a first support surface of the extraction hood into the extraction opening, the stepped reduced

[0019] The gap size also allows for a gradually increased flow velocity. This does not lead to undesirable turbulence within the card, but is more than sufficient for extracting the fibers from the doffer's clothing.

[0020] The speed of the air flow is thus gradually increased before entering the suction opening, whereby almost all fibers can be sucked out of the collector's clothing.

[0021] Further measures improving the invention are described in more detail below together with the description of a preferred embodiment of the invention with reference to the figures.

[0022] They show:

[0023] Fig. 1 is a side view of a schematically illustrated carding machine according to the prior art;

[0024] Fig. 2 is a side view of the area between the drum and the pickup;

[0025] Fig. 3 is an enlarged side view of Figure 2.

[0026] Fig. 1 shows a prior art carding machine in which fiber flakes are guided via a chute to a feed roller 1, a feed table 2, via several licker-in rollers 3a, 3b, 3c, to the drum 4 or the reel tambour. On the drum 4, the fibers of the fiber flakes are parallelized and cleaned by means of stationary and rotating carding elements. The resulting fiber web is then conveyed via a doffer 5, a doctor roller 6 and several squeeze rollers 8, 9 to a web guide element 10, which forms the fiber web into a fiber sliver using a funnel 11. The sliver is then transferred to a downstream processing machine or a can 15 via take-off rollers 12, 13. The removal of the fibers from the doffer 5 is assisted by a web guide profile 7, which is arranged below the doctor roller 6.Above the doctor roller 6, a cleaning roller 6a is arranged, with which fiber residues are removed from the doctor roller 6 and fed to a suction device not further designated.

[0027] The following detailed drawings relate to the transfer area between the drum 4 and the doffer 5. In this illustration, the drum 4 rotates clockwise, whereas the doffer 5 rotates counterclockwise and takes over the carded fiber web. For this purpose, the clothing 5a wound on the doffer 5 is aligned with the tooth direction against the direction of rotation of the doffer 5, as shown schematically in Figure 2. Due to the difference in speed and the difference in diameter between the drum 4 and the doffer 5, the doffer 5 has a much lower peripheral speed than the drum 4, so that the carded fiber web is compressed into the teeth of the doffer 5. The subsequent transfer of the fiber web to the doctor roller 6 is therefore not complete because fibers remain stuck in the tooth base of the clothing 5a.To prevent the clothing 5a of the doffer 5 from becoming temporarily clogged, an extraction hood 25 is arranged in the region of the gusset between the drum 4 and the doffer 5. The extraction hood 25 has an open extraction opening 25a counter to the direction of rotation of the doffer 5. The illustration in Figure 2 shows one or two fixed carding elements 14 above the extraction hood 25, the presence and arrangement of which are not essential to the invention. The elements shown here, fixed carding element 14, gusset profile 20, extraction hood 25 and cover element 26, extend over the entire width of the drum 4 and the doffer 5, which is usually between 1000 mm and 1500 mm today. The area between the drum 4 and the doffer 5 has two gussets. In the upper gusset, the fiber web is transferred from the drum 4 to the doffer 5. Here, the remaining fibers are also removed from the clothing 5a of the doffer 5 by the following invention.In the following, reference is always made to the upper gusset, since an extraction hood arranged in the area of ​​the lower gusset would destroy the fiber pile.

[0028] In the gusset between the drum 4 and the doffer 5, a gusset profile 20 is arranged, which can be designed, for example, to accommodate a temperature sensor. The gusset profile 20 is wedge-shaped in order to be positioned at a constant distance from the drum 4 and the doffer 5. The gusset profile 20 has two leg surfaces 20a, 20b, which are arranged in a wedge shape to one another and protrude into the upper gusset between the drum 4 and the doffer 5. The leg surfaces 20a, 20b have a contour that is concave towards the outside, i.e. towards the circumferential surfaces of the rollers 4, 5, the radius of which corresponds to the radius of the associated roller 4, 5 with clothing, so that a constant gap to the rollers is maintained.Both leg surfaces 20a, 20b are connected by a likewise concave support surface 20c, which, on the one hand, provides the necessary stability to the leg surfaces 20a, 20b, and, on the other hand, corresponds in its outer contour to the curved tubular profile of the suction hood 25 and forms with it a gap b that is at least partially constant over the outer circumference. Consequently, the leg surface 20a, which bears against the drum 4, extends over a larger circumferential area than the leg surface 20b, which only extends almost to the suction hood 25. The leg surface 20a of the gusset profile 20 can extend beyond the vertical extent of the suction hood 25 and up to a fixed carding element 14, if provided.

[0029] The extraction hood 25 is arranged very close to the gusset between the drum 4 and the doffer 5. The arrangement is such that a gap is created between the outer contour of the extraction hood 25 and the gusset profile 20 to form an air flow 27, which will be described below. Referring to Figure 2, the extraction hood 25 is arranged at an angle a of 20° - 40°. The angle a is defined on the one hand by the theoretical transfer point of the fiber web from the drum 4 to the doffer 5, i.e. the point at which the connecting line between the pivot points of the rollers 4, 5 intersects the radius of the rollers 4, 5, which is also the narrowest point between the drum 4 and the doffer 5. On the other hand, the angle a is limited by the connecting line between the pivot point of the doffer 5 and the geometric center of the extraction hood 25.The extraction hood 25 uses the gap at least between the gusset profile 20 and the outer contour of the extraction hood 25 for air flow. The extraction hood 25 is essentially formed by a tubular hollow profile that has two almost flat or slightly concave bearing surfaces 25b and 25c towards the doffer 5, which correspond to the outer contour of the doffer 5 and its clothings. Between the bearing surfaces 25b, 25c there is an opening 25a which is oriented against the direction of rotation of the doffer 5. By means of the bearing surfaces 25b, 25c on the one hand, different distances and thus gaps to the doffer 5 are formed, which affects the air flow in this area. On the other hand, the bearing surfaces 25b, 25c create options for fastening the extraction hood 25 within the card. The first support surface 25b, which is located between the suction opening 25a and the gusset orthe gusset profile 20, is supported by a transition 25d to the tubular cross-section of the extraction hood 25. The transition 25d terminates tangentially with the tubular profile of the extraction hood 25 and has a rounded, aerodynamic contour towards the first support surface 25b. At the same time, the transition 25d and the tubular profile of the extraction hood 25 to the gusset profile 20 form an almost constant gap through which the air flow flows into the extraction opening 25a. The first support surface 25b has a sharp edge 25e arranged towards the extraction opening 25a, which is designed like a knife counter to the direction of rotation of the pickup 5. The distance between the first support surface 25b and the fitting 5a of the pickup 5 is 1mm to 2mm smaller than the distance between the second support surface 25c and the fitting 5a of the pickup 5, which can be 2mm to 4mm.The second support surface 25c is inclined at an acute angle in a small area located toward the suction opening 25a, increasing the distance to the clothing 5a of the collector 5. This facilitates the removal of the fibers from the clothing 5a of the collector 5.

[0030] The suction opening 25a has a clear width with a distance c between the edge 25e and the second support surface 25c of 10 mm to 20 mm. The size or clear width of the suction opening 25a can be designed depending on the flow conditions. The flow conditions depend, among other things, on the design of the card in the area of ​​the doffer and the downstream rollers, namely how much and via which paths fresh air can be drawn in. With a negative pressure of approximately 2 mbar to 4 mbar in the suction hood 25, the clear width with a distance c of 10 mm to 20 mm of the suction opening 25a has proven optimal.

[0031] Furthermore, it has proven advantageous to design the gap or distance b between the outer contour of the extraction hood 25 and the gusset profile 20 between 4 mm and 10 mm. With the aforementioned negative pressure, it is particularly advantageous if the gap or distance b varies within a range between 6 mm and 8 mm. If a fixed carding element 14 is arranged in this area and mounted close to the extraction hood 25, the gap between these two components should preferably also be extended to a distance of 4 mm to 10 mm, preferably between 6 mm and 8 mm.

[0032] The suction hood 25 can be suctioned from one side or both sides. The negative pressure in the suction hood 25 creates an air flow 27, which is sucked into the card by fresh air drawn in from the card or from the environment. The air flow 27 initially concentrates in the gap between the outer contour of the suction hood 25 and the gusset profile 20. Subsequently, the air flow 27 must flow into the suction opening 25a between the even smaller gap of the first support surface 25b and the clothing 5a of the doffer 5, which creates a gradual increase in the flow velocity. The orientation of the suction opening 25a against the direction of rotation of the doffer 5 causes the fibers to be released from the clothing 5a of the doffer 5, so that the doffer can once again take over the full volume of carded fibers from the drum 4.By varying the distances between the support surface 25b, 25c and the clothing 5a of the collector 5, the suction effect is enhanced by the alignment of the edge 25e against the direction of rotation of the collector and the reduced distance between the first support surface 25b and the clothing 5a creating a mechanical and fluid barrier for the fibers remaining in the clothing 5a.

[0033] To prevent incorrect flow directions within the carding machine, a cover 26 is arranged from the suction hood 25, opposite the direction of rotation of the doffer 5, and is positioned at a defined distance from the clothing 5a of the doffer 5. This prevents an air flow that could enter the suction opening 25a below the second support surface 25c. To clean the doffer 5, the cover 26 can be pivotable, for example, attached to the suction hood 25 with a joint or to another component on the outer circumference of the doffer.

[0034] Reference symbol

[0035] 1 feed roller

[0036] 2 dining tables

[0037] 3a, b, c licker-ahead

[0038] 4 drums

[0039] 5 customers

[0040] 5a set

[0041] 6 scraper roller

[0042] 6a cleaning roller

[0043] 7 Fleece guide profile

[0044] 8 Squeeze roller

[0045] 9 Squeeze roller

[0046] 10 fleece guide element

[0047] 11 T funnel

[0048] 12 Take-off roller

[0049] 13 Take-off roller

[0050] 14 Fixed carding element

[0051] 15 cans

[0052] 20 gusset profile

[0053] 20a first leg surface

[0054] 20b second leg surface

[0055] 20c support surface

[0056] 25 Extractor hood

[0057] 25a Suction opening

[0058] 25b first support surface

[0059] 25c second support surface

[0060] 25d transition

[0061] 25th edge

[0062] 26 Cover

[0063] 27 Air flow a Angle b Gap size c Opening width

Claims

AMENDED CLAIMS received by the International Bureau on 22 June 2023 (22.06.2023) Carding machine with a drum (4) and several stationary and rotating carding elements designed to parallelize and clean fibers, so that the resulting fiber pile is subsequently transferred to a take-up device (5), wherein a gusset profile (20) is arranged in the upper gusset between the drum (4) and the take-up device (5), characterized in that a suction-fed extraction hood (25) is arranged on the take-up device (5) in the area of ​​the upper gusset, which generates an airflow (27) during operation of the carding machine, wherein the outer contour of the extraction hood (25) together with the gusset profile (20) forms a gap through which the airflow (27) can enter an extraction opening (25a) of the extraction hood (25) against the direction of rotation of the take-up device (5).Carding device according to claim 1, characterized in that the extraction hood (25) is arranged at an angle (a) of 20° to 40°, formed between the theoretical transfer point of the fiber pile from the drum (4) to the take-up device (5) and by a connecting line between the pivot point of the take-up device (5) and the geometric center of the extraction hood (25). Carding device according to claim 1, characterized in that the gap between the outer contour of the extraction hood (25) and the gusset profile (20) has a gap size (b) between 4 mm and 10 mm, preferably between 6 mm and 8 mm. Carding machine according to claim 1, characterized in that the suction opening (25a) is arranged between a first and a second support surface (25b, 25c), and that the first support surface (25b), which is arranged between the suction opening (25a) and the gusset profile (20), has an edge (25e) which is arranged opposite to the direction of rotation of the pickup (5).Carding machine according to claim 4, characterized in that the extraction opening (25a) has an opening width (c) of 10 mm to 20 mm. Carding machine according to claim 4, characterized in that the first support surface (25b) has a smaller distance to the assembly (5a) of the pickup (5) than the second support surface (25c). Carding machine according to claim 6, characterized in that the distance of the first support surface (25b) to the assembly (5a) of the pickup (5) is smaller than the gap between the outer contour of the extraction hood (25) and the gusset profile (20), such that the. 12 AMENDED SHEET (ARTICLE 19) Airflow (27) from the gap between the outer contour of the extraction hood (25) and the gusset profile (20) is accelerated towards the extraction opening (25a). Carding according to claim 4, characterized in that the second support surface (25c) is inclined at an acute angle in an area arranged towards the extraction opening (25a) such that its distance to the assembly (5a) of the pickup (5) is increased.Method for operating a carding machine with a drum (4) and several stationary and rotating carding elements designed to parallelize and clean fibers, so that the resulting fiber pile is subsequently transferred to a take-up device (5), wherein a gusset profile (20) is arranged in the upper gusset between the drum (4) and the take-up device (5), characterized in that a suction-fed extraction hood (25) is arranged on the take-up device (5) in the area of ​​the upper gusset, which generates an airflow (27) within the carding machine, wherein the airflow (27) passes through a gap between an outer contour of the extraction hood (25) and the gusset profile (20) against the direction of rotation of the take-up device (5) into an extraction opening (25a) of the extraction hood (25), so that fibers are sucked out of the assembly (5a) of the take-up device (5).The method of claim 9, characterized in that the airflow (27) is guided between the outer contour of the extraction hood (25) and the wedge profile (20) and subsequently flows between a first support surface (25b) of the extraction hood (25) into the extraction opening (25a). The method of claim 10, characterized in that the velocity of the airflow (27) is increased stepwise before entering the extraction opening (25a). 13 AMENDED SHEET (ARTICLE 19)

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