GB2092627A - Apparatus for separating and feeding chopped fibres - Google Patents

Abstract

Apparatus for separating and feeding chopped fibres (e.g. chopped strand glass fibres) comprises a hopper (10) which receives the chopped fibres and an inclined conveyor (15) which forms one side of the hopper (10) and which has projecting hooks (18) which engage bundles of interlocked fibres and lifts them over the side of the hopper (10). The fibres are then received by a rotary member (21), which has a number of outwardly extending pins, hooks or prongs (24) which pass between the teeth of three stationary combs (27, 28 and 29) as the rotary member (21) rotates. The bundles of fibres picked up by the outwardly extending pins, hooks or prongs (24) are thus separated by the teeth of the combs (27, 28 and 29). Preferably, a second rotary member (30) also carries rows of pins, hooks or prongs (32) interfitting with the pins, hooks or prongs (24) of member (21), and with the teeth of a fixed comb (34) to effect final separation of the fibre strands. The separated fibre strands may be conveyed onwards through an air duct (36). <IMAGE>

Description

SPECIFICATION Apparatus for separating and feeding chopped fibres This invention relates to apparatus for separating and feeding chopped fibres, e.g.

chopped strand glass fibres.

Chopped fibres, particularly chopped strand glass fibres, have a strong tendency to mat and interlock once they have been chopped to the desired length (conventionally 3 to 50 mm). It is then difficult to separate them into random dispersed strands and the longer the chopped strands the greater is the difficulty. The matted and interlocked bundles of fibre cannot, for example, conveniently be mixed into a matrix, for example a slurry or a liquid resin compound, for production of a glass fibre reinforced product until they have been separated into random dispersed strands. If the dispersal is effected by intensive mixing of the glass fibre with the matrix, mechanical damage to the fibres is generally caused which reduces the strength of the reinforced product.

It is an object of the invention to provide an apparatus for separating and feeding chopped fibres, e.g. chopped strand glass fibres, which will provide a stream of dispersed fibres without causing substantial mechanical damage to the fibres.

According to the invention, apparatus for separating and feeding chopped fibres comprises a hopper for receiving the chopped fibres, a conveyor forming one side of the hopper and carrying projecting members for engaging bundles of interlocked fibres and lifting them over the said side of the hopper, a rotary member comprising a plurality of outwardly extending members, disposed so as to receive the bundles of fibres from the conveyor, at least one comb having teeth interfitting with the outwardly extending members of the rotary member so that the outwardly extending members pass between the teeth during rotation of the rotary member, whereby the bundles of fibres picked up by the outwardly extending members are separated by the teeth of the comb or combs.

In a preferred embodiment the conveyor is inclined relative to the vertical so as to facilitate the lifting and separating of the fibres, and conveniently the projecting members of the conveyor are in the form of pins, hooks or prongs.

The rotary member may take the form of a generally cylindrical drum with its outwardly extending members, such as pins, hooks or prongs, spaced around the circumference of the drum, the length of the outwardly extending members being less than or substantially the same as the diameter of the drum. Alternatively the outwardly extending members of the rotary member can be carried on a rotatable shaft having a diameter less than the length of the outwardly extending members. The latter arrangement is particularly suited when it is desired to arrange the rotary member adjacent one side of the conveyor with the outwardly extending members interfitting with the projecting members carried by the conveyor.

Conveniently the or each comb can be arranged in a stationary position by mounting it or them on a wall or walls adjacent the rotary member. In one embodiment a comb is mounted on a wall adjacent to a side of the rotary member remote from the conveyor, the comb acting on the bundles of fibres carried between the outwardly extending members of the rotary member. In another embodiment these stationary combs are spaced around the periphery of the rotary member so as to act in succession on the bundles of fibres.

The fibres separated by the teeth of the comb or combs may pass directly to a conveying device for feeding the fibres onwards or may be allowed to fall directly into a matrix in which they are to be mixed. The conveying device may be a pneumatic conveyor which draws the separated fibres into an air stream.

The apparatus preferably also incorporates a second rotary member comprising a plurality of outwardly extending members, disposed on the opposite side of the first rotary member from where the latter receives the bundles of fibres, the second rotary member having its outwardly extending members interfitting with those of the first rotary member at said opposite side, the second rotary member being rotatable in the same sense as the first rotary member so that the outwardly extending members of the first rotary member at said opposite side have a motion opposed to the motion of the interfitting outwardly extending members of the second rotary member, thereby assisting in the separation of the bundles of fibres into individual strands.In embodiments in which such a second rotary member is provided, it is advantageous to provide a further stationary comb disposed with its teeth interfitting with the outwardly extending members of the second rotary member to effect final separation of the bundles of fibres.

The invention will now be described in more detail, by way of example, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic vertical section through an apparatus according to the present invention for separating and feeding chopped strand glass fibres, and Figure 2 is another embodiment of an apparatus according to the present invention.

In the apparatus illustrated in Figure 1, a hopper 10 for receiving chopped strand glass fibres has a fixed vertical side wall 11, an inclined bottom 12, an open top 14 and end walls (not shown) parallel to the plane of the paper. On the right hand side as seen in the drawing, the side of the hopper 10 is formed by an inclined conveyor 15, which is a lattice-type conveyor running upwardly on its side facing the internal space of the hopper and over pulleys 16, 1 7. The conveyor 1 5 carries horizontal rows of projecting hooks 1 8 whose ends 1 9 are directed upwards when travelling up the side of the hopper 10. The hooks thus engage bundles of interlocked fibres in the hopper 10 and lift them over the side of the hopper formed by the conveyor 15.

The length of the hooks 1 8 is such that they extend beyond the centre of gravity of the average bundle of fibres so that, as the bundle is carried out of the mass of fibres, its connection with the mass is broken. The horizontal rows of hooks 1 8 are spaced apart by a distance sufficient to ensure that the average fibre bundle will not form a bridge between adjacent rows of hooks, leaving the space between the rows empty. In some cases, straight pins or prongs may be used in place of the hooks 18.

A vertical wall 20 joined to the end walls of the hopper 10 guides the bundles of fibres downwards to the separating means.

The separating means comprises a generally cylindrical rotary member 21 which effectively closes the exit from the space 22 into which the fibre bundles fall and which is defined by wall 20, an extension 23 of the bottom 12 of the hopper, and the end walls (not shown) of the hopper. The rotary member 21 comprises a plurality of rows of outwardly extending pins, hooks or prongs 24 fixed in a cylindrical drum 25 which is driven to rotate in the sense of the arrow 26, the length of the pins, hooks or prongs 24 being less than the diameter of drum 25.

The pins, hooks or prongs 24 of the rotary member 21 interfit with the teeth of three stationary combs 27, 28 and 29 mounted respectively on the bottom of wall 20, on a fixed casing 33 surrounding member 21 and on the lower end of extension 23 of the bottom of the hopper. The pins, hooks or prongs 24 thus pass between the teeth of the combs 27, 28, 29 in succession during rotation of the rotary member 21. Bundies of fibres picked up by the pins, hooks or prongs 24 are thus separated into small bundles.

To assist the separation of the small bundles into individual strands, a second rotary member 30, driven to rotate in the sense of the arrow 31, is disposed on the opposite side of member 21 from where the latter receives the bundles of fibres. The rotary member 30 also carries rows of outwardly extending pins, hooks or prongs 32 which interfit with the pins, hooks, or prongs 24 of the member 21. They also interfit with the teeth of a fixed comb 34 mounted on the fixed casing 33 to effect final separation of the fibre strands.

The fixed casing 33 has an inclined floor 35 which at its lower end opens into an air duct 36 forming part of a pneumatic conveyor for conveying the separate fibre strands onwards, e.g.

to a mixer where they are mixed into a cement slurry for forming glass fibre reinforced cement.

Air flow in the duct 36 is produced in the direction of arrow 37 by means of a fan 38 and induces air from the casing 33, thus drawing the separated fibre strands into the air stream and conveying them onwards.

An alternative embodiment is illustrated in Figure 2. The features of the apparatus of Figure 2 which are the same as features of the apparatus of Figure 1 are designated by the same reference numerals.

In Figure 2 a glass roving chopping unit 40 is disposed at the open top 14 of the hopper in the vicinity of the fixed vertical side wall 11. The unit 40 comprises two cooperating rotating cylinders, one of which carries chopping blades 401. Glass rovings fed to the unit 40 are thus chopped directly above the hopper and the resulting chopped strand glass fibres fall directly into the hopper 10. The conveyor 1 5 carries rows of pins 42 which engage bundles of interlocked fibres in the hopper 10 and lift them over the side of the hopper formed by the conveyor 1 5. A flexible brush 41 is carried on a projection 43 depending from the inclined bottom 12, the brush 41 sealing off the gap between the bottom 12 and the pulley 17.

The length of the pins 42, like that of the hooks 18 in Figure 1, is such that the pins 42 extend beyond the centre of gravity of the average bundle of fibres so that, as the bundle is carried out of the mass of fibres, its connection with the mass is broken. Like the hooks 18 in Figure 1 , the rows of pins 42 are spaced apart by a distance sufficient to ensure that the average fibre bundle will not form a bridge between adjacent rows of pins 42, leaving the space between the rows empty.

The bundles of fibres that have been lifted over the top of conveyor 1 5 either fall downwards away from the conveyor to the separating means or are carried downwards by the pins 42 to the separating means.

The separating means comprises a rotary member 44 having a plurality of outwardly extending pins, hooks or prongs 46 carried on a rotatable shaft 48 having a diameter less than the length of the pins, hooks or prongs 46, the rotatable shaft 48 being driven to rotate in the sense of arrow 50.

The pins, hooks or prongs 46 of the rotary member 44 interfit with the downwardly moving pins 42 fixed to the conveyor 1 5 and also interfit with the teeth of a stationary comb 52 mounted on the wall 20.

A second rotary member 54, driven to rotate in the same sense (see arrow 56), is disposed below the rotary member 44 and receives bundles of fibres from the rotary member 44. The rotary member 54 has a rotatable shaft 60 which carries rows of outwardly extending pins, hooks or prongs 58 which interfit with the pins, hooks or prongs 46 of the rotary member 44. They also interfit with the teeth of a fixed comb 62, mounted on the wall 20 below the fixed comb 52, so as to effect final separation of the fibre strands.

The separated fibre strands then fall into a region defined between the lower portion of wall 20, a short inclined wall 66 and a flexible brush 68 sealing off the gap between wall 66 and the pulley 17.

As in the embodiment of Figure 1, air flow in the duct 36 is produced in the direction of arrow 37 by means of a fan 38 and induces an air flow in the direction of arrows 64, thus drawing the separated fibre strands into the air stream and conveying them onwards. The fan 38 is driven by a motor 70.

In Figures 1 and 2 the conveyor 1 5 is shown as a lattice conveyor inclined to the vertical. It may, however, if desired be disposed substantially vertically such that it is orientated parallel to the vertical wall 20.

It is to be understood that the conveyor 1 5 can take any other suitable form, for example it can take the form of a generally cylindrical rotatable drum disposed so as to form one side of the hopper and carrying projecting members for engaging bundles of interlocked fibres and lifting them over the side of the hopper.

In addition the combs 27, 28, 29, 34, 52 and 62, although being shown as being fixedly mounted to their respective walls so as to be stationary, can if desired be pivotally mounted on their respective walls so as to give a freedom of movement to the combs. In addition, although in each of the embodiments described above a pneumatic conveyor is provided for conveying the separated fibre strands onwards, the pneumatic conveyor can be dispensed with and the separated fibre strands allowed to fall from the separating means directly down into a cement slurry for forming into a glass fibre reinforced cement product.

Claims (14)

1. Apparatus for separating and feeding chopped fibres comprising a hopper for receiving the chopped fibres, a conveyor forming one side of the hopper and carrying projecting members for engaging bundles of interlocked fibres and lifting them over the said side of the hopper, a rotary member comprising a plurality of outwardly extending members, disposed so as to receive the bundles of fibres from the conveyor, and at least one comb having teeth interfitting with the outwardly extending members of the rotary member so that the outwardly extending members pass between the teeth during rotation of the rotary member, whereby the bundles of fibres picked up by the outwardly extending members are separated by the teeth of the comb or combs.

2. Apparatus according to Claim 1, wherein the conveyor is inclined relative to the vertical.

3. Apparatus according to Claim 1 or 2 wherein the projecting members of the conveyor are in the form of pins, hooks or prongs.

4. Apparatus according to any one of the preceding claims wherein the rotary member is in the form of a generally cylindrical drum with its outwardly extending members, such as pins, hooks or prongs, spaced around the circumference of the drum, the length of the outwardly extending members being less than or substantially the same as the diameter of the drum.

5. Apparatus according to any one of Claims 1 to 3, wherein the outwardly extending members of the rotary member are carried on a rotatable shaft having a diameter less than the length of the outwardly extending members.

6. Apparatus according to Claim 5, wherein the rotary member is arranged adjacent one side of the conveyor with the outwardly extending members interfitting with the projecting members carried by the conveyor.

7. Apparatus according to any one of the preceding claims wherein the or each comb is arranged in a stationary position by mounting it or them on a wall or walls adjacent the rotary member.

8. Apparatus according to Claim 7, wherein a comb is mounted on a wall adjacent to a side of the rotary member remote from the conveyor, the comb acting on the bundles of fibres carried between the outwardly extending member of the rotary member.

9. Apparatus according to Claim 7, wherein the stationary combs are spaced around the periphery of the rotary member so as to act in succession on the bundles of fibres.

1 0. Apparatus according to any one of the preceding claims further comprising a conveying device for feeding the fibres onwards.

11. Apparatus according to Claim 10, wherein the conveying device is a pneumatic conveyor which draws the separated fibres into an air stream.

1 2. Apparatus according to any one of the preceding claims wherein a second rotary member comprising a plurality of outwardly extending members is disposed on the opposite side of the first rotary member from where the latter receives the bundles of fibres, the second rotary member having its outwardly extending members interfitting with those of the first rotary member at said opposite side, the second rotary member being rotatable in the same sense as the first rotary member so that the outwardly extending members of the first rotary member at said opposite side have a motion opposed to the motion of the interfitting outwardly extending members of the second rotary member, thereby assisting in separating the bundles of fibres into individual strands.

13. Apparatus according to Claim 12, further comprising a stationary comb disposed with its teeth interfitting with the outwardly extending members of the second rotary member to effect final separation of the bundles of fibres.

14. Apparatus for separating and feeding chopped strand glass fibres, substantially as herein before described with reference to the accompanying drawing.