GB2095866A

GB2095866A - Controlling web production

Info

Publication number: GB2095866A
Application number: GB8033975A
Authority: GB
Original assignee: Cosmopolitan Textile Co Ltd
Current assignee: Cosmopolitan Textile Co Ltd
Priority date: 1980-10-22
Filing date: 1980-10-22
Publication date: 1982-10-06
Also published as: FR2492353A1; IT8168363A0; DE3141796A1; IT1144974B

Abstract

A web fabricated from flowable material 11 (which can be not only fluids but also particles of textile fibres, either loose or in the form of a fleece) is weighed continuously or at intervals at 14 as it is collected in continuous form at 13 from the fabrication process 12 and running weight (weight per unit length) calculated from the weighing and the linear rate of production and used to control the supply of the flowable material so as to tend to maintain the running weight constant. <IMAGE>

Description

SPECIFICATION Controlling web production This invention relates to the control of the fabrication of a continuously produced article of elongated form (particularly, though by no means exclusively, a textile article such as a fabric, sliver, web or the like) fabricated from material (such as a textile fibre for example) supplied in a flowable state to the fabrication process. Any such article is for convenience referred to hereinafter simply as "a web".By "flowable" is meantflowable in the sense of comprising loose fibre or granules or other particulate material as well as in the sense of comprising an actual fluid (which might for example be supplied as a coating for a substrate) and in the case of fibre the term "flowable" is also to be understood to apply to fibre in the form of a fleece insofar as the running weight of a fleece can be modified by lenthwise stretching or contraction -this applies particulalrrly to fleece produced by carding and cross-folding as is conventional in the production of stitch bonded fabrics.

In the production of webs such as stitch bonded fabrics or coated fabrics it is desirable to produce a web, the running weight of which is within the customer's specification or without using too much fibre or coating material which would add to the production cost. (The "running weight" is the weight per unit length of web which is of course related to weight per unit area). This is effected by feeding the material into the fabrication process at as uniform a rate as possible and by operating the fabrication machinery at a constant speed. Various arrangments are used for controlling the input of fibre, for example, to the fleece preparation machinery of a stitch bonding or other non-wovens machine to be uniform orto produce a uniform fleece running weight which is fed to the machine.

Nevertheless, the running weight of the web is not known to be what is required until a piece is cut from the fabricated web and weighed. Not only does this spoil the continuity of the web - so that there is a tendency to check less frequently than might be necessary - but the weighing process takes time so that if the fabric is found to be over- or under-weight a correction will not be applied until quite a lot of over- or under-weight fabric has been produced and even then itwill not be known until the next weighing whether the applied correction has brought the running weight back to specification.

The present invention provides a method of control that does not spoil the continuity of the web and which results in a more uniform web produced more closely to the specified running weight than is poss ible using conventional techniques.

The invention comprises a method for controlling the running weight of a web fabricated from material supplied in a flowable state to the fabrication process, in which the running web is collected in continuous form after fabrication and the so-called web is continuously weighed, the linear rate of production of the web is continuously measured and the running weight of the web is calculated continuously, the supply of said material to the fabrication process being adjusted relatively to the linear rate of production of the web so as to tend to maintain the running weight of the web constant.

Where the web is a non-woven fabric and the material comprises textile fibres supplied to the fabrication process in the form of a fleece, the fleece may be supplied on a fleece delivery conveyor, the speed of which is adjusted relative to the linear rate of fabric production. The conveyor may itself receive fleece from a fleece preparation process supplied with loose fibre and then the rate at which fleece is prepared in said fleece preparation process may be controlled in accordance with the speed of the said fleece delivery conveyor. However, the supply of loose fibre to a fleece preparation process integrated with the web fabrication process may be controlled directly by the calculated running weight of the fabric.

By the expressions "continuously weighed", "continuously measured" and "calculated continuously" is meant not only truly continuous weighing, measurement and calculation but also frequent or regular spot observations and calculation. For example, the running weight may be checked every five minutes during a non-wovens manufacturing process, or at intervals corresponding to the production of 50 metres or 100 metres of fabric, say.

The running web may be collected by web collecting apparatus which is weighed together with the web being collected. The increment of weight per unit length of web collected then gives the running weight of the web.

The web collecting apparatus is preferably such that neither tension in the web nor the momentum of the web as it is supplied to the web collecting apparatus substantially affects the weighing of the collected web. The web collecting apparatus may comprise web winding means for winding the web into a roll and may stand on a load cell or like direct weighing device and the web is supplied horizontally thereto so that web tension exerts no vertical component of force on the said web collecting apparatus.

In another arrangement, the web collecting apparatus may be balanced on a weigh beam and the web supplied thereto along a path which is aligned with the pivot of the beam.

Said web collecting apparatus may, again, comprise trolley means into which the web is delivered and a weigh plate arrangement on to which the trolley can be positioned to receive the web.

The calculation of the running weight may be carried out by a microprocessor connected to effect required adjustment of the supply of material to the fabrication process relative to the linear rate of production of the web.

Although it is envisaged that the linear rate of production of the web will normally be held constant at the maximum or optimum production rate of the fabrication apparatus, and the supply of material to The drawing(s) originally filed were informal and the print here reproduced is taken from a later filed formal copy.

the fabrication process adjusted so as to tend to maintain the running weight of the web constant, it could also be arranged that the supply of material be held constant and the speed of the fabrication process adjusted instead -or both could be altered together for purposes of regulation.

The invention also comprises apparatus for controlling the running weight of a web fabricated from material supplied in a flowable state to web fabrication apparatus comprising web collecting means for collecting the running web in continuous form after the fabrication apparatus, weighing means for continuously weighing the web collected by the web collecting means, measuring means for measuring the linear rate of production of the web, calculating means for continuously calculating the running weight of the web, and control means for adjusting the supply of said material to said web fabrication apparatus relatively to the linear rate of production of the web so as to tend to maintain the running weight of the web constant When a microprocessor is used to effect the calculation and control it may be equipped with a visual display unit to display the measurements and calculation and it may also effect or supply data by which another machine can effect logging of the amount of web produced and material used for inventory purposes.

Embodiments of apparatus and method for controlling the running weight of a web fabricated from material supplied in a flowable state to the fabrication process according to the invention will now be described with reference to the accompanying drawings in which: Figure lisa block diagram of a fabrication plant and control means therefor, Figure 2 is a diagrammatic elevation of a web winding apparatus, Figure 3 is a diagrammatic illustration of another web winding apparatus, Figure 4 is a diagrammatic illustration of a web collecting trolley arrangement, Figure 5 is a block diagram of a stitch bonding plant and control means therefor and Figure 6 is a block diagram of a stitch bonding plant and alternative control means therefor.

The web fabrication plant illustrated in Figure 1 comprises a material feed arrangement 11 from which material is supplied in a flowable state to web fabricating apparatus 12 from which the fabricated web is collected in continuous form in web collecting apparatus 13. The socollected web is continuously weighed and a signal representative of the weight fed, together with a signal representative of the linear rate of fabrication of the web, to means 14 in which the running weight of the web is calculated continuously.

The operation of the material feed arrangement 11 is controlled by the calculating means 14 so asto adjust the supply of material relative to the linear rate of production of the web so as to tend to maintain the running weight of the web constant Figure 2 illustrates one form of web winding apparatus for collecting the web in which the web 21 is rolled up on a mandrel 22 resting on support and drive rollers 23 driven by an electric motor 24 (which may be controlled for example to run at a speed corresponding to the rate of production of the web or which may be controlled so asto keep the winding tension constant or vary it in a desired way during the build-up of the roll) the whole being mounted on a weigh-plate arrangement 25.The web 21 is supplied to the roll horizontally so as notto exertany vertical component of its tension on the winding apparatus.

Figure 3 shows an arrangement in which the web 31 is rolled up on a mandrel 32 which is balanced on a weigh beam 33. Here the web 31 is guided on a fixed guide roller 34 close to the pivot 35 of the weigh beam so that during the rolling up ofthe web, tension in the web acts through or substantially through the pivot 35 and does not affecrthe weigh Fng.

Figure4 illustrates an arrangement in which a trolley 41 is supplied with web 42 from a folding device 43. The trolley 41 is run on wheels 44 on to a weigh plate 45.

In all three arrangements, the weight of the web collecting apparatus-the mandrel 22, rollers 23 and motor 24 of Figure 2 or the mandrel 32 and associated equipment of Figure 3, or the trolley 41 of Figure 4 - is immaterial in that it is the weight increment that is used in the calculation.

Figures 5 and 6 show arrangements of stitch bonding plant in which the control of running weight is effected in different ways. In both Figures the stitch bonding plant comprises loose fibre feed apparatus 51, a carding machine 52, a cross folder 53, a stitch bonding machine 54 and a fabric collecting arrangement 55. A microprocessor 56 receives continuous weight measurements from the fabric collecting arrangement 55 and also measurements of the linear rate of fabric production from the stitch bonding machine 54.

In the embodiment shown in Figure 5, the microprocessor 56 controls through control means 57 the speed of a fleece delivery conveyor 58 which also controls the speed of the carding machine 52 and cross-folder 53. In the embodiment shown in Figure 6, the carding machine 52 and cross-folder 53 are run at constant speed but the rate of delivery of loose fibre by the fibre feed arrangement 51 is controlled directly by the microprocessor 56.

References throughout the specification and claims to a load cell are to be understood to include not only a single load cell but also a plurality of such which operate collectively to measure the weight which they support.

Claims

1. A method for controlling the running weight of a web fabricated from material supplied in a flowable state to the fabrication process, in which the running web is collected in continuous form after fabrication and the socollected web is continuously weighed, the linear rate of production of the web is continuously measured and the running weight of the web is calculated continuously, the supply of said material to the fabrication process being asjusted relatively to the linear rate of production of the web so as to tend to maintain the running weight of the web constant.

2. A method according to claim 1, in which the web is a non-woven fabric and the material comprises textile fibres supplied to the fabrication process in the form of a fleece.

3. A method according to claim 2, in which the fleece is supplied on a fleece delivery conveyor, the speed of which is adjusted relative to the linear rate of fabric production.

4. A method according to claim 3, in which said conveyor receives fleece from a fleece preparation process supplied with loose fibre.

5. A method according to claim 4, in which the rate at which fleece is prepared in the said fleece preparation process is controlled in accordance with the speed of the said fleece delivery conveyor.

6. A method according to claim 2, in which the fabrication process receives fleece from a fleece preparation process supplied with loose fibre and the rate of supply of loose fibre thereto is controlled by the running weight of the fabric.

7. A method according to any one of claims 1 to 6, in which the running web is collected by web collecting apparatus which is weighed together with the web being collected.

8. A method according to claim 7, said web collecting apparatus being such that neither tension in the web nor the momentum of the web as it is supplied to said web collecting apparatus substantially affects the weighing of the collected web.

9. A method according to claim 7 or claim 8, said web collecting apparatus comprising means for winding the web into the roll.

10. A method according to claim 9, in which the web collecting apparatus stands on a load cell or like direct weighing device and the web is supplied horizontally thereto so that web tension exerts no vertical component of force on the said web collecting apparatus.

11. A method according to claim 9, in which the web collecting apparatus is balanced on a weigh beam and the web is supplied to the said apparatus along a path which is aligned with the pivot of the beam.

12. A method according to claim 7 or claim 8, said web collecting apparatus comprising trolley means into which the web is delivered and a weigh plate arrangement on to which the trolley can be positioned to receive the web.

13. A method according to any one of claims 1 to 12, in which the calculation of the running weight is made in a microprocessor connected to effect required adjustment of the supply of material to the fabrication process relative to the linear rate of production of the web.

14. A method for controlling the running weight of a web fabricated from material supplied in a flowable state to the fabrication process, substantially as herein described with reference to the accompanying drawings.

15. Apparatus for controlling the running weight of a web fabricated from material supplied in a flowable state to web fabrication apparatus, comprising web collecting means for collecting the running web in continuous form after the fabrication apparatus, weighing means for continuously weighing the web collected by the web collecting means, measuring means for measuring the linear rate of production of the web, calculating means for continuously calculating the running weight of the web, and control means for adjusting the supply of said material to said web fabrication apparatus relatively to the linear rate of production of the web so as to tend to maintain the running weight of the web constant.

16. Apparatus according to claim 15, in which said web fabrication apparatus comprises a machine for making a non-woven fabric

17. Apparatus according to claim 16, in which said machine comprises a stitch bonding machine.

18. Apparatus according to claim 16 or 17, comprising fleece delivery means delivering fibre in the form of a fleece to the said fabrication apparatus, and said control means acts on said fleece delivery means to control the speed of fleece delivery relative to the linear rate of web production.

19. Apparatus according to claim 16 or claim 17, comprising loose fibre feeding means supplying loose fibre to said fabrication apparatus, said control means acting to adjust the rate at which said loose fibre feeding means supplies fibre to said fabrication apparatus.

20. Apparatus according to any one of claims 15 to 19, comprising web collecting apparatus and weighing means for weighing the same together with the web being collected.

21. Apparatus according to claim 20, said web collecting apparatus being arranged so that neither tension in the web nor the momentum of the web as it is supplied to the said web collecting apparatus substantially affects the weighing of the collected web.

22. Apparatus according to claim 20 or claim 21, comprising web winding means.

23. Apparatus according to claim 22, in which said web winding means stand on a load cell or like direct weighing device and the web is supplied horizontally thereto.

24. Apparatus according to claim 22, in which said web winding means are balanced on a weigh beam and web guide means are supplied for guiding the web along a path which is aligned with the pivot of the beam.

25. Apparatus according to claim 20 or claim 21, said web collecting apparatus comprising trolley means into which the web can be delivered, and a weigh plate arrangement on to which the trolley can be positioned to receive the web.

26. Apparatus according to any of claims 15 to 24, comprising microprocessor means connected to effect required adjustment of the supply of material to the fabrication apparatus relative to the linear rate of production of the web.

27. Apparatus for controlling the running weight of a web fabricated from material supplied in a flowable state to the fabrication apparatus, substantially as hereinbefore described with reference to the accompanying drawings.