The invention concerns a method as defined in the preamble of claim 1 for determin- ing the quality of the formation of a reel or roll of a paper or board web and for controlling the reel or roll formation.

In reeling or winding of paper or of some other, equivalent web-like material, in the forming of machine reels, a so-called Pope-type reel-up is employed commonly. In a Pope-type reel-up the paper reel is formed by loading the reel against a Pope drum. On the other hand, in slitter-winders, in which customer rolls are formed, winders of the drum winder type are used commonly. In a drum winder, there are two winding drums, on whose support the paper roll is formed. The paper roll that is being formed is loaded by means of rider rolls which are brought into contact with the top face of the paper roll. From the drum winder, a winder with a set of belt rolls has been developed further, in which one of the winding drums has been substituted for by two smaller rolls which are surrounded by an endless carrier belt that supports the paper roll. In slitter winders, a centre-drive winder is also employed, in which the roll is formed on support of one winding drum so that the roll is constantly supported from its centre by means of an adjustable hydraulic support.

When a paper web or equivalent is reeled or wound, it is the aim that the web that is formed should be reeled or wound onto the reel or roll as evenly as possible in order that the reel or roll should become of uniform quality in view of further processing. In order that this aim could be achieved, a number of different methods and apparatuses have been suggested by whose means the reeling or winding process can be controlled. In practice, the reeling or winding process can, however, not be controlled completely, and in reeling or winding defects unavoidably arise in some

reels or rolls. Since such defects cause problems in the further processing of the reeled or wound material, it would be advantageous if the defective reel or roll, the location of the defect in the reel or roll, and the nature of the defect could be identified right in the stage of reeling or winding.

Predicting of a deficiency in the structure arising from reeling or winding and of the presence of damage arising from said deficiency in the web is, however, not reliably possible to-day. This is why, if it is suspected that, for example, in a line of paper manufacture, in a machine reel, there is bottom damage or other damage, in the unwinding taking place in the next process stage, a sufficiently large bottom portion is allowed to remain so as to be on the safe side. Since bottom damage that results in web breaks does, as a rule, not occur systematically in every machine reel, as a result of such a procedure, unnecessary broke and, thus, also unnecessary economic losses arise. Similarly, web damage in customer rolls causes web breaks in the printing machine, which is an undesirable situation from the point of view of the printing operator, because it lowers the efficiency of the printing machine.

Methods of NDT (Non-destructive testing) of machine reels and of rolls in general have not been developed very actively, in spite of the necessity of availability of such methods. Research has been carried out, among other things, into tomography and into thermographic analysis. Experiments have provided promising results, but the methods would still require abundant further development before they could be utilized for predicting of structural defects in a reel or roll. In particular, for analysis of a machine reel, there are not sufficiently large tomographic apparatuses, and the cost would probably constitute an obstacle for development of such an apparatus.

Thermography is restrictive in the sense that the examination is carried out by depicting the surface or the end of the reel or roll. In such a case, the results are based on observation of the difference in temperature arising from movements between layers of paper and produced by friction heat, which does not state more precisely where and what sorts of reeling or winding defects have arisen. Further, the stability of the emission coefficient of the paper, for example, in situations of pressing, is not known.

With respect to thermographic analysis, reference can be made to the publication WO 95/27676, in which a method is described by whose means the higher tempera- ture of a defective point in a reel or roll is measured by means of a thermograph.

Thus, thermal radiation is measured here. Thermal radiation, i. e. infrared radiation, is electromagnetic radiation, which is transmitted by every object whose temperature is above the absolute zero point. Thermal rays move at the speed of light. The intensity of the radiation depends on the temperature of the object and on the wave length of the radiation. With the exception of a fully black object, every object also reflects and absorbs radiation coming from other sources. Defects in a reeling or winding process are converted to heat, for example, by the effect of friction, which slows down, equalizes and weakens the interdependence between the impulse and the signal and, thus, makes the method deficient.

When a customer roll or a machine reel becomes larger, in the reeling or winding situation various bangs and creaks are often heard, which arise from relative move- ments of layers of paper in the roll or reel. These sounds are also observed in situations of braking and acceleration of a roll or reel. The human ear cannot detect from where the sounds arise and what is, thus, more precisely taking place in the interior of the roll or reel. Sounds arising from life in the reel are indicative of changes taking place in the structure of the machine reel. Sounds in a certain frequency range indicate the formation of a detrimental reeling or winding defect.

The principal characteristics of the method in accordance with the invention come out from the characterizing part of claim 1.

In the method in accordance with the invention, the quality of a reel or roll is determined by, from the reel or roll, analyzing the signal produced by impulses arising, in connection with reeling or winding or with unwinding, from relative movements of web layers and/or from damaging of the web. Said signal can be measured either by means of measurement fully free of contact or by means of measurement with contact. In contact-free measurement, the sound-frequency signal emitted by the impulses in the air is measured. In measurement with contact, the

signal of oscillation produced by the impulses in the mechanical parts of the reel-up or winder is measured. On the basis of the signal produced by said impulses and arising from the reel or roll in connection with reeling or winding, it is directly possible to change the regulation parameters of reeling or winding, such as the linear load and/or the profiling of the linear load and/or the centre torque and/or the web tension. As soon as it can be concluded on the basis of said signal that some sort of a disturbance is about to arise in the reeling or winding, one or several regulation parameters in the reeling or winding is/are altered, in which case the disturbance can be eliminated completely or its effect can at least be reduced.

Thus, the present invention is related to utilization of mechanical oscillation (mech- anical oscillation and sound) in the papermaking process. The sound consists of wave motion. A sound wave propagates in a medium, based on an interaction of atoms and molecules, both as a longitudinal wave and as a transverse wave. In a gaseous medium, such as air, wave motion is, however, always longitudinal. A sound that propagates by the intermediate of air consists of longitudinal mechanical oscillation of air molecules, variations in pressure that have received the impulse at the interface between air and solid matter from mechanical oscillation of solid matter.

Thus, within the scope of the idea of the present invention, it is possible that, besides the mechanical oscillation applied by the impulses in the frame constructions, it is also possible to utilize the longitudinal wave motion (oscillation in the air) in the air produced by the same mechanical oscillation, i. e. a sound-frequency signal. The impulses in a reeling or winding process produce an immediate impulse as a sound and as an impulse of mechanical oscillation applied to the frame constructions, in which case the method in accordance with the present invention permits very quick reactions to defects that arise.

The information that represents the quality of the reel or roll and that was deter- mined on the basis of said signal in connection with reeling or winding can also be used in connection with subsequent unwinding. In unwinding, it is known if the reel or roll is free from defects, and, if the reel or roll is not free from defects, it is known precisely in which locations in the reel or roll any deficiencies are present

and what the nature of the deficiencies is. In this way it is possible to utilize a maximal proportion of the reel or roll, and any allowance for broke, to be on the safe side, is avoided.

Thus, the analyzing takes place mainly in connection with reeling/winding and unwinding, but, for example, out of a machine reel, it is also possible to analyze signals in a storage situation in which the reel is rotated slowly.

By means of the solution in accordance with the invention, it is possible to automate a system of predicting reeling or winding defects based on an analysis of a sound- frequency signal propagating in the air or based on an analysis of an oscillation signal propagating in solid matter. The information obtained through a detector mounted on a reel-up, a slitter-winder or on some other apparatus for unwinding or reeling/winding is processed in digital form, and by making use of, for example, self-organized charts or some other, equivalent method, formation of reeling/winding defects is predicted. A similar method is utilized, for example, in analyzing the breathing sound of a human being. First, a sufficient number of reeling/winding processes and their web-break data are instructed to the self-organized chart, after which the system is capable of concluding the occurrence of defects on the basis of what it has learnt.

It is an advantage of the invention that the analysis can be carried out directly in connection with the process of manufacture without in any way disturbing the process itself or its running. If contact-free measurement is used, the analysis can be carried by means of one detector, for example a microphone, and by means of the information on the time of formation of the sound/by means of data on the diameter of the reel or roll, without necessity of monitoring the precise location of formation of the sound by means of a number of microphones.

The reference with which the collected information is compared is, for example, the sound produced by a bottom defect, a sound connected with problems of tightness of the reel or roll, a sound related to defects in the surface of paper, or any other,

equivalent indicator related to the quality of the reel or roll. This requires an unam- biguous and clear method of monitoring of reeling/winding defects in order that the data on reeling/winding defects that are fed into the system are expressly data arising from reeling/winding defects and not, for example, arising from torn edges or similar external matters.

In analyzing the information obtained from impulses related to reeling/winding defects, the procedure must be such that it is first determined at what frequencies the reel or roll emits said impulses in order that it could be known what frequency bands are analyzed. This takes place so that the desired reels or rolls are analyzed. At the same time it is found out what types of detectors and filtrations and other possible processing must be used in order that the impulses from the reel or roll related to reeling/winding defects can be separated from the background noise. In this connec- tion, it must also be taken into account that reeling/winding defects are of different types for different paper grades because of their different stock compositions, so that the collecting of reference data must be carried out separately for each paper grade.

The impulses emitted by a reel or roll may also involve differences arising from the line of manufacture, so that this must also be taken into account when reference data are being collected.

In the following, the invention will be described with reference to the figures in the accompanying drawings, the invention being, however, not supposed to be confined to the details of said illustrations alone.

Figure 1 is a schematic illustration of a drum winder.

Figure 2 shows a winder with belt rolls, which is a variation of a drum winder.

Figure 3 is a schematic illustration of a centre-drive winder.

Figure 4 is a schematic illustration of a Pope-type reel-up.

Figure 5 shows a process diagram of a method in accordance with the invention.

Figure 6 illustrates the amplitude of an oscillation signal as a function of time.

Fig. 1 shows a normal drum winder suitable for formation of customer rolls, which winder consists of a first 11 and a second 12 winding drum, on which the paper roll 10 is formed. The figure further shows the rider rolls 13 which load the paper roll 10. In this exemplifying embodiment, the paper web W or equivalent enters onto the lower face of the first winding drum 11, from which it is transferred along the face of the first winding drum 11 through the nip NP 1 formed by the first winding drum 11 and the upper paper roll 10 onto the paper roll 10.

Fig. 2 shows a winder with a set of belt rolls, which is a modification of a drum winder. In this winder with a set of belt rolls, there is also a first winding drum 17, but the second winding drum has been substituted by a paper roll 10 support construction consisting of two rolls 18,19 and of an endless carrier belt 20 that surrounds said rolls. This also includes rider rolls 13 that load the paper roll 10.

Fig. 3 shows a centre-drive winder. In the centre-drive winder the web W arrives on the lower face of the winder drum 16, from which it is transferred through the nip NP1 formed between the winder drum 16 and the paper roll 10 onto the paper roll 10. The paper roll 10 is supported from its centre by means of support arms 40, which can be regulated by means of hydraulic cylinders 41.

Fig. 4 shows a Pope-type reel-up suitable for formation of machine reels and consisting of a reeling drum 15, onto which the paper web W is passed and from which the web is transferred through the nip NP1 formed between the reeling drum 15 and the paper reel 10 that is being formed onto the paper reel 10.

In all of the reeling/winding devices shown in Figs. 1 to 4, the detector 30 can be placed, for example, in the vicinity of the paper reel/roll 10 that is formed and/or, for example, at the centre 30'of a reeling/winding drum 11,15,16,17 or in some

other suitable location in the reeling/winding device. The number of detectors 30, 30'that are needed is at least one, but there may be several detectors, in which case they are preferably placed in different locations in the vicinity of the paper reel/roll that is being formed. If contact-free measurement of sound information is concerned, the detector can be placed freely in the vicinity of the reeling/winding device, but an oscillation measurement detector with contact must be attached to the mechanical parts of the reeling/winding device.

Fig. 5 illustrates a block diagram of the method in accordance with the invention.

The reference numeral 100 represents the reeling/winding process proper, from which the signal produced by the impulses arising from relative movements of web layers and/or from damaging of the web is collected. The reference numeral 101 represents a detector which converts the signal produced by said impulses into an electric signal. If measurement of sound information is concerned, a microphone is employed, and if oscillation measurement is concerned, an oscillation detector is employed. The analog electric signal that contains the sound information and that is obtained from the output port 101b of the detector 101 is passed further to the input port 102a of the AD converter 102. In the AD converter 102 the analog signal is converted into a digital signal and passed further into the first input port 103ail of the computer 103. In the computer 103, the signal in the digital form is compared with the self-organized chart, which contains history information on reeling/winding processes. On the basis of the comparison, the computer produces the quality report of the reeling/winding by means of an output producing apparatus. The information obtained from the new reeling/winding process is also fed into the computer 103 as an addition to the existing history data, in which connection the computer 103 "learns"more all the time. An A/D converter may also be integrated in the detector 101, in which case the detector 101 produces a digital signal directly as an output signal, and a separate A/D converter 102 is, thus, not needed.

In Fig. 5, the procedure related to the feed of starting data necessary in connection with the introduction of the method is represented by the reference numeral 104.

When a method of the sort described above is taken into use for the first time, the

starting data must first be run into the self-organized chart of the computer. This takes place so that a signal produced by impulses arising from relative movements of web layers and/or from damaging of the web is collected from a relatively large number of reels/rolls, from which defects are analyzed in connection with the collecting and/or later. When measurement is carried out, the information collected based on said signal and the proceeding of the reeling/winding of the web to be reeled/wound must be synchronized in order that it could be known to what location in the reel/roll each item of information refers. When the complete reels/rolls have been analyzed in connection with reeling/winding and/or with subsequent unwinding, the defective points in each roll and the related signals can be interrelated. This information is then fed as starting data into the self-organized chart of the computer to the second input port 103a2 of the computer. In a way, a learning process is concerned, in which the computer is"taught"with what criteria it has to identify different defects in the reeling/winding.

Information collected concerning reeling/winding defects can also be utilized directly as a control parameter for regulation of the control of reeling/winding, for example, for regulation of the linear load and/or of the profiling of the linear load and/or of the centre torque and/or of the web tension. The information collected concerning reeling/winding defects can also be utilized in connection with subsequent process stages in connection with unwinding of the reel/roll. In such a case it is known if the reel/roll is free from defects, and if it is not free from defects, it is known at which locations there are defects and of what nature the defects are.

The information collected by means of the solution in accordance with the invention can also be utilized in the control of the process of manufacture of the material, for example paper, that is concerned at each particular time, i. e. in the regulation/control of preceding parts/actuators in the paper machine. Based on information of a failure in the reel-up/winder, what can be concerned is, for example, regulation of profiles of thickness, moisture, basis weight, tension, fibre orientation, or equivalent both in the cross direction of the machine and in the machine direction.

As an example, it can be stated that a so-called smiling thickness profile produces bottom defects in a machine reel, which defects are expressed as sharp bangs during the reeling as well as layers projecting a few millimetres from the reel edge. In such a case, based on these bangs, it is possible to adjust the thickness profile or at least to give the alarm concerning a deficient profile, in which case due action can be taken in order to correct the profile.

Thus, in the analyzing proper, a process is concerned in which, on one hand, abnor- malities are looked for when good rolls and bad rolls are compared with each other, and, on the other hand, typical features of a bad roll are also looked for.

Fig. 6 illustrates the amplitudes A of two different oscillation signals S1 and S2 as a function of time T. The amplitude has been scaled in the range 0... 4. The oscilla- tion signal S1 has a point D1 that indicates a reeling/winding defect, has very steep sides, and is clearly distinguished from the background noise, and, similarly, the oscillation signal S2 has a point D2 that indicates a reeling/winding defect and rises and goes down less steeply. What is concerned is a fictive example of what the impulses that indicate reeling/winding defects could be like.

In the following, the patent claims will be given, and the details of the invention may show variation within the scope of the inventive idea defined in said claims and differ from what has been stated above for the sake of example only.