GB2493824A

GB2493824A - Fibre Web Support and Guide capable of Directing Airflow within the carding machine

Info

Publication number: GB2493824A
Application number: GB1213509.1A
Authority: GB
Inventors: Christoph Leinders
Original assignee: Truetzschler GmbH and Co KG
Current assignee: Truetzschler GmbH and Co KG
Priority date: 2011-08-19
Filing date: 2012-07-30
Publication date: 2013-02-20
Anticipated expiration: 2032-07-30
Also published as: BR102012020746A2; DE102011110681A1; BR102012020746B8; GB201213509D0; BR102012020746B1; CN102953165B; CH705409A2; CH705409B1; GB2493824B; CN102953165A; ITMI20121167A1

Abstract

In a device on a carding machine arranged between a doffer 5 and two nip rolls 7, 8, there is provided below the stripper roll 6 a stationary element 17 whose upper surface faces the stripper roll and the front surface faces the lower nip roll. The edge between the upper surface and the front surface is arranged in the region between the stripper roll and the nip rolls. This edge is oriented in the direction towards the nip between the nip rolls. A fibre web passes over the upper surface and then through an open space to the nip between the nip rolls. In order to provide a way of improving guidance of the fibre web, the region of the supporting and guiding element 17 that faces the lower nip roll 8 is constructed with a surface, which may be curved, facing towards the lower nip roller 8 so that the flow of air B is guided in a direction opposite to the direction of rotation of the lower nip roller, 8a. The gap between the supporting/guiding element and the lower nip roller may be adjustable to alter the airflow profile over the machine width.

Description

Device on a carding machine for cotton, synthetic fibres and the like, arranged between a doffer and two nip rolls The invention relates to a device on a carding machine for cotton, synthetic fibres and the like, arranged between a doffer and two nip rolls, in which there is provided below the stripper roll a stationary supporting and guiding element.

It is known to provide a supporting and guiding element in which the upper surface faces a part of the stripper roll and a front surface of which faces the lower nip roll, the edge between the upper surface and the front surface being arranged in the region between the stripper roll and the nip rolls and being oriented in the direction towards the nip between the nip rolls. A fibre web passes over the upper surface and then through an open space as far as the nip between the nip rolls.

A known device (DE 43 28 431 A) is in practice in operational use in large numbers without problems and has become widespread. At a delivery speed of up to about 330 rn/mm, a profile closed in the form of a supporting and guiding body is used. The front surface of the element facing the lower nip roll is flat. At elevated delivery speeds and also if the working width is relatively large, disruptive air currents can act on the sensitive fibre web.

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, provides a simple way of improving guidance of the fibre web, especially in the case of a relatively large working width and/or an elevated delivery speed.

The invention provides a device on a carding machine comprising, arranged between a doffer and two nip rolls, a stripper roll and, provided below the stripper roll, a statIonary supporting and guiding element the upper surface of which faces a region of the stripper roll and a further surface region of which faces the lower nip roll, a downstream edge of said upper surface being arranged in the region between the stripper roll and the nip rolls and being oriented in the direction towards the nip between the nip rolls, the arrangement being such that in use a fibre web passes over the upper surface and then through an open space to the nip between the nip rolls, wherein the region of the supporting and guiding element that faces the lower nip roll is so formed that a flow of air is guided in a direction opposite to the direction of rotation of the lower nip roll.

As a result of the measures taken according to the invention, the outlet opening for the entrained air is configured in such a way that, by virtue of the geometry of the web guide profile, the flow of air is directed downwards in a direction opposite to the direction of rotation of the lower nip roll. Preferably, the flow profile over the width of the machine is influenced by variation of the gap between the web guide profile and the nip roll. This is preferably achieved by the front edge of the profile being, for example, of concave or convex construction.

Advantageously, the region facing the lower nip roll comprises the front surface of the supporting and guiding body. Advantageously, the region facing the lower nip roll comprises the edge between the front surface and the upper top surface of the supporting and guiding body.

Advantageously, the flow of air is present in the space between the supporting and guiding body, the stripper roll and the nip roll.

Advantageously, the region facing the lower nip roll is aerodynamically shaped. In one embodiment, the front surface is at least partly curved. For example, the curve may be concave or may be convex. In certain embodiments, the front surface may have openings for the passage of air. Advantageously, the flow profile over the machine width is variable by varying the gap between the supporting and guiding profile (web guide profile) and the nip roll. Advantageously, the front edge of the web guide profile is concave. Advantageously, the front edge of the web guide profile is convex. Advantageously, the web guide profile consists of an extruded aluminium profile.

Preferably, the web guide profile is a hollow profile.

Advantageously, the gap between the front surface of the supporting and guiding element and the circumferential surface of the lower nip roll widens towards the bottom.

The invention further provides a device on a carding machine for cotton, synthetic fibres and the like, arranged between a doffer and two nip rolls, in which there is provided below the stripper roll a stationary element the upper surface of which faces a region of the stripper roll and the front surface of which faces the lower nip roll, and in which the edge between the upper surface and the front surface is arranged in the region between the stripper roll and the nip rolls and is oriented in the direction towards the nip between the nip rolls, wherein a fibre web passes over the upper surface and then through a free space as far as the nip between the nip rolls, wherein the region of the supporting and guiding element that faces the lower nip roll is constructed in such a way that the flow of air is guided in a direction opposite to the direction of rotation of the lower nip roll.

One illustrative embodiment of the invention will be described in detail below with reference to the accompanying drawings, in which: Fig. 1 is a side view, shown in diagrammatic form, of an illustrative embodiment of the device according to the invention on a carding machine; Fig. 2 shows the supporting and guiding element of Fig. 1 in section; and Fig. 3 is a side view, on an enlarged scale, of a part of the carding machine shown in Fig. 1, with the supporting and guiding element of Fig. 2, showing the aerodynamically constructed surface facing the lower nip rolls.

With reference to Figure 1, a carding machine, for example a flat card TC, made by Trutzschler GmbH & Co.KG of F4bnchengladbach, Germany, has a feed roll 1, feed table 2, lickers-in 3a, 3b, 3c, cylinder 4, doffer 5, stripper roll 6, nip rolls 7, 8, web guide element 9, web funnel 10, delivery rolls U, 12, revolving flat top 13 with flat guide rollers 13a, 13b and flat bars 14, can 15 and coiler 16. Reference letter M denotes the centre point (axis) of the cylinder 4. Reference numeral 4a denotes the clothing and reference numeral 4b denotes the direction of rotation of the cylinder 4. Arrow A denotes the working direction.

The curved arrows drawn inside the rolls indicate the directions of rotation of the rolls. Reference numeral 17 denotes the supporting and guiding element according to the invention.

Referring to Fig. 2, the supporting and guiding element 17 has in essence an approximately triangular cross-section. The upper surface 17' is slightly concavely curved. The radius of curvature of the curve of the surface 17' is greater than the radius of the stripper roll 6. The arrow A indicates the running direction of the fibre web (not shown) . The front end region has an edge 17-'; the rear end region 172 is rounded. The edge 171' prevents deposition of contaminants, for example honeydew.

The surface 17' is cleaned, for example of trash, by the web passing over it. The cross-sectional shape of the element 17 is matched to the air flow conditions in the region between the doffer, the stripper roll and the nip rolls 7, 8. The front surface, that is, the surface that is facing generally downstream in the working direction A, is indicated by reference numeral 17''. The rear surface of element 17, that is, the surface that is facing generally upstream with respect to working direction A, is indicated by reference numeral 17'' With reference to Fig. 3, the upper surface 17' of the element 17 faces the clothing (not shown) of the stripper roll 6. One end region (the upstream region) of the element 17 is associated with the nip between the doffer 5 and the stripper roll 6. The other end region (the downstream region) is arranged in the region between the stripper roll 6 and the nip rolls 7, 8, the edge l7i' being oriented in the direction towards the nip between the nip rolls 7, 8. In the embodiment shown, the element 17 is an extruded profile, for example made of aluminium, having an internal cavity.

As Fig. 3 shows, the region 17'' (front surface) of the supporting and guiding element 17 that faces the lower nip roll 8 is concave, so that the flow of air B is guided in a direction opposite to the direction of rotation 8a of the lower nip roll 8. The gap between the front surface 17 and the circumferential surface 8b of the lower nip roll 8 widens approximately conically towards the bottom.

This provides a certain nozzle action which promotes the diversion of the air flow B. In the embodiment shown in Fig. 3, that is achieved by forming the curved front surface 17'' of the guiding element 17 with a radius of curvature larger than the radius of nip roll 8.

The device according to the invention has the special advantage that on the one hand the front region -seen in the working direction A -of the upper surface of the supporting and guiding element 17 extends as far as a point close to the nip between the nip rolls 7, 8 and on the other hand disruptive air currents are diverted downwards from the space between the nip rolls 7, 8 and the stripper roll 6, that is to say through the space between the supporting and guiding element 17 and the lower nip roll 8. That lower space can be in communication with an extraction device.

Claims

<claim-text>Cia ± ins 1. A device on a carding machine comprising, arranged between a doffer and two nip rolls, a stripper roll and, provided below the stripper roll, a stationary supporting and guiding element the upper surface of which faces a region of the stripper roll and a further surface region of which faces the lower nip roll, a downstream edge of said upper surface being arranged in the region between the stripper roll and the nip rolls and being oriented in the direction towards the nip between the nip rolls, the arrangement being such that in use a fibre web passes over the upper surface and then through an open space to the nip between the nip rolls, wherein the region of the supporting and guiding element that faces the lower nip roll is so formed that a flow of air is guided in a direction opposite to the direction of rotation of the lower nip roll.</claim-text> <claim-text>2. A device according to claim 1, wherein the further surface region comprises the front surface of the supporting and guiding body.</claim-text> <claim-text>3, A device according to claim 2, wherein the further surface region comprises an edge defined between the front surface and the upper surface of the supporting and guiding body.</claim-text> <claim-text>4. A device according to claim 2 or claim 3, wherein the front surface is aerodynamically shaped.</claim-text> <claim-text>5. A device according to any one of claims 2 to 4, wherein the front surface is at least partly curved.</claim-text> <claim-text>6. A device according to claim 5, wherein the front surface is concavely curved.</claim-text> <claim-text>7. A device according to claim 5, wherein the front surface is convexly curved.</claim-text> <claim-text>8. A device according to any one of claims 2 to 7, wherein the front surface has openings for the passage of air.</claim-text> <claim-text>9. A device according to any one of claims 1 to 8, wherein the flow of air is present in the space between the supporting and guiding element, the stripper roll and the nip roll.</claim-text> <claim-text>10. A device according to any one of claims 1 to 9, wherein the flow profile over the machine width is variable by varying the gap between the supporting and guiding element and the nip roll.</claim-text> <claim-text>11. A device according to any one of claims 1 to 10, wherein the downstream edge of the upper surface of the supporting and guiding element is concave.</claim-text> <claim-text>12. A device according to any one of claims 1 to 11, wherein the downstream edge of the upper surface of the supporting and guiding element is convex.</claim-text> <claim-text>13. A device according to any one of claims 1 to 12, wherein the supporting and guiding element consists of an extruded aluminium profile.</claim-text> <claim-text>14. A device according to any one of claims 1 to 13, wherein the supporting and guiding element is a hollow profile.</claim-text> <claim-text>15. A device according to any one of claims 1 to 14, wherein the further surface region of the supporting and guiding element is so contoured that it forms a gap between the further surface region and the circumferential surface of the lower nip roll that widens towards the bottom.</claim-text> <claim-text>16. A device on a carding machine having a stationary supporting and guiding element substantially as described herein with reference to and as illustrated by any of Figs. 1 to 3.</claim-text>