GB2298660A - Device for opening bundles of fibres - Google Patents

Description

BAD ORIGINAL 1 Device for opening bimu.Lei:s uL L.L&jA=D 2298660 The

present invention relates to a device for opening bundles of fibres of various types, for instance natural and synthetic fibres. Opening fibre bundles is a conventional technique and is necessary in order to prepare them for carding or other treatment processes to ensure a good quality product.

Fibre bundle opening devices (openers) are well known and generally feature means of drawing up or propelling the bundles and of projecting the said bundles either onto drums provided with teeth or between disks.

The drum-type devices, as for example described in U.S. Patent 4 426 753, have the drawback that the active zone in which the opening takes place is limited to the contact zone between two cylinders. However, evacuation of the fibres from this zone is facilitated given that the centrifugal force created by the rotation of the drums acts perpendicularly to the axis of the drums and removes the fibres from the teeth.

The disk-type opening devices, as for example described in French Patent 1 303 869, feature two disks or disk portions, one fixed and one rotating, and the opposing faces of these two disks are equipped at least partially with teeth. The active zone of such a device is distinctly larger than in the case of the drum-type devices and above all depends on the path which the bundles are to follow between the two disks. On disktype devices the centrifugal force created by the rotating disk acts perpendicularly to the disk's axis but in the plane of the teeth. It is therefore distinctly more difficult to evacuate the fibres than in the case of the drum-type devices.

To this end various solutions have already been proposed, all of which concern the positioning of the teeth.

According to French Patent 1 303 869 the teeth of the rotating disk are brought progressively closer to 1 2 the teeth of the fixed disk as the distance increases from the system's axis (where the bundles enter). Therefore little carding takes place at the beginning and it only becomes effective towards the point where the fibres exit.

According to British Patent 1 009 284 the number of teeth is small and the fixed and moving teeth are not situated opposite one another.

According to International Patent Application No. 92/14872 the teeth are sloping and situated a certain distance from one another, making it possible for the bundles to pass through the device without undergoing carding. Moreover, the use of sloping teeth involves complex engineering.

The systems known to date therefore all have drawbacks in terms of carding intensity.

It is therefore the object of the present invention to propose a device for opening fibre bundles which combines the advantages of the disk-type devices with those of the drum-type devices.

According to the invention the bundles of fibres are projected between teeth, on the one hand, on the convex side of the casing of a tapered body and, on the other hand, on the concave side of the casing of a body incorporating a tapered receptacle.

The device according to the invention therefore comprises a rotating part, hereinafter referred to as the turbine, which is tapered in form, mounted on a shaft and driven by a motor. The convex side of the casing of the cone is equipped with teeth, needles or some other point used in the fibre bundle opening process. These teeth are preferably placed substantially perpendicularly to the convex plane of the casing. The device comprises a fixed part incorporating a form of tapered recess and positioned opposite the rotating part. on the concave side one sector of the casing is likewise equipped with teeth.

is 3 The convex plane of the rotating part and the concave plane of the fixed part will preferably be substantially parallel and the teeth of the two parts will preferably be aligned towards one another, with a gap between them.

The centrifugal force created by the turbine no longer acts perpendicularly in the plane of the teeth, but creates a component which facilitates the progress and evacuation of the fibres that have undergone opening by passing via the teeth.

These two parts (rotating and fixed) are preferably situated in one enclosure which is connected to the motor actuating the turbine, to a fibre.feeder duct and to a fibre evacuator duct.

According to one preferred embodiment of the invention, the motor is situated on one of the lateral faces of the enclosure and the feeder duct opens out onto the lateral face opposite to the face fitted with the motor.

According to one practical embodiment of the invention, the fixed part is fitted with teeth on a sector covering 25 to 50 % of its surface. A further sector or feed zone is designed for feeding and a third sector or fibre evacuation zone for evacuating the fibres.

Means are preferably provided to prevent the bundles from passing from the feed zone to the fibre evacuation zone without passing through the toothcovered sector.

Advantageously the distance between the fixed part and the rotating part can be adjustable and the device is constructed in a manner allowing the teeth to be adapted to suit the type of bundles to be opened. The distance between the teeth on the convex surface and the teeth on the concave surface is preferably uniform.

According to a further feature of the invention, a feed system on the device has a shape which is part 4 is annular or elliptical in form, and this allows the inlet to have the maximum dimensions and hence a broad distribution of the material over the surface of the turbine is possible, thereby avoiding excessive shock to the bundles, damage to the fibres and blockages of the device, and potentially resulting in optimum opening of the material.

The fibres are projected axially between the teeth of the turbine. The conical shape of the two parts (fixed and rotating) and the perpendicular arrangement of the teeth with respect to their surface then forces the fibres to leave the teeth of the turbine and, in their radial trajectory produced by the centrifugal force, to enter the teeth of the fixed mating part. The result is an outstanding carding action.

The invention will now be described in detail with the help of a nonlimitative working example and with reference to the accompanying drawings, wherein: 0 Figure la shows an elevational view of the device with the door open; 0 Figure ib shows a plan view of the device seen in Figure 1a; Figure 2 shows a plan view of the closed device; Figures 3a and 3b show perspective views of two variants of feeder pipes.

Referring now to the Figures, the opening device comprises a structure 21 forming a sealed enclosure featuring a frame 4 and a swing door 3 fixed on the frame 4 by means of hinges 22. Flanged on the outer face of the door 3 is a motor 2 whose shaft carries, on the inner face of the door 3, a turbine 1 with a tapered shape. Perpendicularly to the convex face of the turbine I the latter is covered with a plurality of rows of teeth 11.

Inside and opposite the turbine, the structure 21 includes a tapered recess, the concave part of which is divided into four sectors. The first sector 5 has a part annular opening and is joined to a feed pipe 9 for the fibre bundles. The second sector 6 has radial rows of teeth 12, and the third sector has a tangential opening 7 joined to a pipe for evacuating the processed bundles.

Between sector 5, the inlet for the bundles, and sector 7, the outlet for the processed bundles, there is a fourth sector 8 which forms an isolation chamber 8 delimited substantially radially by the walls 13 and 14 and whose job it is to prevent the bundles from passing directly from sector 5 to sector 7 without passing through the processing sector 6.

When the door 3 is closed, the walls 13 and 14 are brought longitudinally as close as possible to the teeth 11 on the turbine 1, with the result that only air is able to pass into the gap between the teeth 11 and the walls 13 and 14. An adjustable opening 15 is provided in the chamber 8 to permit the entry of air from outside the enclosure, if necessary. At the centre of its plane face the tapered recess features a structure 17. This structure may be open and receive the plane face 18 of the turbine when the door 3 is closed.

The concave part, or at least sector 6 of the structure of the tapered recess, is fixed in the enclosure 21 by means of slides or other means (not shown), so as to allow the distance between the convex part and the concave part to be adjusted, and in particular between teeth 11 and 12. This is because the said teeth 11 and 12 are positioned on the convex is and concave faces in a manner allowing them to be removed and they may be interchanged to suit the type and structure of the bundles to be processed. It is important that the distance between the teeth 11 and the teeth 12, and also the walls 13 and 14, should be adjustable accurately.

At the time of the operation the fibres arrive via 6 is the feed pipe 9, enter the machine through zone 5 and are projected against the teeth 11 of the turbine 1. The turbine 1 rotates in the arrowed direction 10 and draws the fibres towards zone 6 with fixed teeth 12. After centrifugation, the fibres are then carded by the relative motion of the moving teeth 11 of the turbine 1 and the fixed teeth 12 of sector 6. Zone 6 therefore constitutes the carding zone.

At the outlet from zone 6, the fibres are drawn away from the teeth of the turbine 1 by an airstream created by a fan (not shown) situated downstream of the outlet 7.

The chamber 8 makes it possible to prevent part of the air entering the arrival zone 5 from being drawn straight to the exit zone 7 by the fan and perhaps taking with it fibres that would consequently not pass through the carding zone 6. Due to the depression created by the fan, air may be drawn in from outside the enclosure through the external opening 15 provided in the chamber 8.

Figure 3a shows the shape of the feed pipe 9, which is generally circular in section at one end 19, given that it forms part of a complex fibre processing installation. Towards the other end, the pipe 9 broadens out and progressively assumes a shape which in section becomes part annular 16. This part annular sector 16 corresponds to the shape of the opening in sector 5 of the tapered recess. According to the variant shown in Figure 3b, the pipe 9 progressively assumes an elliptical shape 20 which can be reflected in the shape of the opening in sector 5.

It is clear that the centrifugal force created by the turbine 1 no longer acts in the plane of the teeth 11 and 12, but creates a component which facilitates the progress of the fibres from zone 6 towards the evacuation zone 7.

In the example under consideration, the active 7 carding zone 6 makes up approximately 40 % of the concave part of the tapered recess. This proportion is not critical, although it has been noted that it is difficult for the fibres to flow properly if more than 50 to 55 % of the said concave part is allocated to the active zone. Conversely, if this active zone is reduced to less than 25 li, the output of the device will be poor.

It will be readily understood that the example outlined above in no way limits the invention and that a person skilled in the art may adopt whatever modifications he deems necessary for the application envisaged.

8

Claims (12)

1. A device for opening bundles of fibres, comprising an enclosure, a motor which drives a rotor inside the enclosure, the surface of the rotor having teeth, a fixed part also having teeth, a fibre bundle feed duct and an evacuating duct for the processed bundles, wherein the rotor is tapered and has a convex surface with a series of pointed elements thereon, and the fixed part comprises a tapered body having a concave surface opposed to the convex surface of the rotor, the concave surface of the tapered body comprising a toothed sector having a series of pointed elements, a feed sector communicating with the fibre bundle feed duct, an evacuating sector having a tangential opening communicating with the evacuating duct for the processed bundles, and blocking means preventing bundles from passing from the feed sector to the evacuating sector without passing through the toothed sector.

2. A device according to claim 1, wherein the convex surface of the rotor and the concave surface of the tapered body are parallel.

3. A device according to claim 1 or 2, wherein the pointed elements of the rotor extend perpendicularly to the convex surface thereof and the pointed elements of the fixed part extend perpendicularly to the concave surface of the tapered body.

4. A device according to any one of the preceding claims, wherein the toothed sector of the tapered body covers 25 to 50 % of the concave surface thereof.

9

5. A device according to any one of the preceding claims, wherein the feed sector has an opening which is part annular or elliptical.

6. A device according to any one of the preceding claims, wherein the feed duct broadens out and progressively assumes a sectional shape which is part annular or elliptical.

is 1

7. A device according to any one of the preceding claims, wherein the blocking means comprise an isolation chamber having an adjustable air inlet.

8. A device according to any one of the preceding claims, wherein the distance between the pointed elements of the rotor and the pointed elements of the fixed part is adjustable.

9. A device according to any one of the preceding claims, wherein the motor is fixed on a lateral face on the outside of the enclosure and the said lateral face comprises a door for access to the rotor and the tapered body.

10. A device according to any one of the preceding claims, wherein the pointed elements are removable.

11. A device for opening bundles of fibres, comprising a tapered rotor driven by a motor, the rotor having a convex surface with a series of pointed elements thereon, and a fixed part comprising a tapered body having a concave surface opposed to the convex surface of the rotor, the concave surface of the tapered body having a sector with a series of pointed elements thereon.

12. A device for opening bundles of fibres, substantially as described herein with reference to the accompanying drawings.