Weblike materials refers, in this connection, to different kinds of materials which are manufactured like web. Such materials are especially materials/products manufactured in paper industry, such as paper, cardboard, pulp etc. as well as other materials/products.

While manufacturing weblike materials their various properties are defined and measured in various stages of the manufacturing process. These properties have influence on the manufacturing process of weblike material and the final product.

The more information one has about properties of weblike material during various stages the faster one is able to react when necessary and possibly to change factors having influence on various properties in various stages of manufacturing.

While measuring properties of weblike materials radiation is aimed to weblike material from one or several radiation sources and by measuring the radiation reflected and/or passed through it values of various properties are detected. There are methods in which properties of continuous material web are measured by means of radiation sources from which radiation is conducted by means of fibres in supporting bars near material web to material web and properties of material web are calculated from the radiation passed through and/or reflected from it.

Disadvantage in these methods appears to be the not simultaneous measuring at different measuring points leading to delay in measuring and the meassuring surface is not a line and it is not possible to measure the whole web width because it is not possible to measure across the whole web width simultaneously.

In measuring properties electromagnetic radiation i. e. gamma, X-ray, UV, light, IR and radio radiation are used. In the following text by the word radiation is meant electromagnetic radiation suitable for the purpose.

While manufacturing weblike materials circumstances around weblike material i. e. inside the machinery at some points of the manufacturing process don't allow to place measuring equipment near weblike material or it doesn't function properly. In

these kind of places there are difficult circumstances around a material web such as high moisture content and/or high temperature and other circumstances which hinder the functioning of measuring equipment and especially their electronics.

Measuring of properties of a material web is difficult in these kind of places.

In paper manufacturing water is removed as efficient as possible in the beginning end of a paper machine. At first water is removed by suction through the wire in which 97 % of the water amount is removed and at highest 20 % dry solids content is achieved. Next there is a pressing section in a paper machine where about 2 % of the whole water amount is removed. After this paper web continues to a drying section where less than 1 % of the whole water amount is removed by evaporating.

Water removing in the drying section is based on heat transmission, which appears by conducting while surfaces of steam heated cylinders touch the paper web.

Material transmission i. e. outlet of evaporated water is carried out by means of hot air, while hot air can carry more water vapour than cold air. This warm air is blown to various places in drying section after warming. A drying section, so called drying hood, is the longest and the most expensive part of a paper machine because water evaporation is a slow and energy consuming process.

Today moisture content i. e. water removal from paper inside the drying hood is measured by means of measuring devices held in hand but those are not suitable for permanent use and they are not capable of measuring various properties across the whole web width.

The most important factors in paper manufacturing for quality and runnability of paper are high dry solids content and stable moisture profile after pressing section.

Most web breaks occur explicitly between pressing section and the first drying group. Defects due to moisture profile of the web, on the other hand, may be the greatest individual reason for rejection of rolls.

The most critical point in paper web handling is the first removal of paper web from a pressing reel, felt or transporting belt. The higher dry solids content and therefore tensile strength are the better paper web can bear the removal. The removal of paper web stretches the web. The high and even dry solids content minimizes the permanent stretch, which allows greater changes in tension in drying groups, post- handling and later in processing.

Wet areas, which often occur due to profile changes after pressing section may easily lead to turning black in calendering as well as forming rolls uneven by

thickness. This is why web must be overdried. Defects in moisture profile easily lead to fluttering edges, which causes, for its part, breaks in drying section.

Changes in moisture content form areas which are more stretchy, slighter or which tension differs from surroundings. These easily form bags, crackings and wrinkles to web inside a roll.

Circumstances in early stage of manufacturing paper in a paper machine are such that they don't allow reliable measure moisture content. Especially moisture of paper can't be measured across the whole web width. Because of too fast drying paper loses some of its absorption abilities and its softness, which, for its part, worsen the smoothness of paper and has also influence on the coat weight. All this has influence on the quality of paper.

The object of the invention is to provide a method, which eliminates the disadvantages in current measuring methods of properties of a material web. The object of the invention is, especially, to provide a method by means of which it is possible to measure properties of a paper web during the early stage of manufacturing process of paper as well as in other stages in difficult circumstances as well as in cross direction of the whole web at the same time. Furthermore, the object of the invention is to provide a method, by means of which it is possible to accomplish measurements quickly, reliably and definitely.

The object of the invention is accomplished by a method the characteristics of which are presented in the claims.

In the method in accordance to the invention radiation is aimed to weblike material and properties are measured from the weblike material across the whole web width 100 % of the area longitudinally such, that at least moisture content and some other property of the weblike material are measured at the same point of the weblike material. While measuring various properties at the same time across the whole web width by combining results information about various properties may be gathered across the whole width and not only from a certain area.

In an advantageous application of the invention various properties are measured from a weblike material at the same point. Thus may be measured various optical properties like moisture content, gloss, speed, grammage, thickness at the same point. When various properties have been measured across the whole web width and at the same point by combining results information about various properties may be gathered from an exact point and/or the whole width of the web. Analyzing

these combinations of partial results gives new information about the state and quality of the process. Changes in thickness and grammage, for example, give information, for instance, about porosity, condition of rollers etc. Measurements of various properties are carried out eighter physically at the same point or from a certain distance in a certain time, but also in that case at the same point of the web and across the whole web width. In this case the changes in length and width may be measured in very short time.

In the second advantageous application of the invention a rather narrow measuring band is used in measuring, which is advantageously smaller than 100 nm. While the range of measuring is very narrow external disturbing factors may not have influence on measurements and even small changes in properties may be measured.

In an advantageous additional application of the invention the radiation sources are pulsed at the same time across the whole width of the web. In this case measurement is carried out exactly at the same time in cross direction of the web, and the measuring points are located on the same cross directional line or on a line that is at an arbitrary angle with the web. A linelike measuring surface is required when paper web is wanted to be measured one hundred percent. Measurement of reference value is carried out the same way.

In an additional application radiation sources and detectors are placed outside the material web in a space with relatively good circumstances. Thus this equipment doesn't suffer circumstances as much as equipment placed next to the material web.

Equipment according to the method is easy to maintain i. e. components are easy to be changed even during the process. Furthermore, process may safely be run even if one source of radiation or a detector was broken because other parts function normally. In paper manufacturing radiation sources and detectors are placed outside paper web and/or pressing part and/or drying hood or other part of manufacturing process with difficult circumstances in a space, where circumstances are relatively good.

The method is suitable also for measuring various properties of a paper web in difficult circumstances. It may be applied for measuring, for example, following properties: moisture content, speed, holes, defects, temperature profile, web width, place of the edge of the web, temperature of the web, tension of the web, grammage, edge cuts, web break profile, uncoated places, dirt, gloss, formation, thickness profile, coat weight, fibre orientation, ash content, roughness as well as their combinations.

A moisture content of a paper web is measured in a recognized way from absorption peaks of water. As measuring point of moisture content for example 1,94 um absorption peak may be chosen and as reference measuring point for example 1,8 urn.

A moisture profile of a paper web may be measured for example at the beginning of the drying section. Thus may, for example, too quick drying be prevented, which causes loss in absorption ability and softness of paper, which, for its part, worsens smoothness and has influence on the coat weight. Especially in film coating, which is popular today, even absorption of the coating is an essential demand.

Furthermore, functioning of the pressing section may be optimized i. e. costs of pressing felts/consumption of drying vapour, because the more pressed the more pressing felts wear out. Also the quality of paper may be optimized because more pressing diminishes paper bulk and stiffness which are important properties in all papers and cardboards. Measuring may also be utilized by having influence on the amount of chemical pulp, because dry solids content may also be raised by adding chemical pulp. This is, though, an extremely expensive way in comparison with good functioning of a pressing section.

While moisture content is measured before and after the drying section exact amount of evaporated water may be calculated. Thus may the amount of air coming to the dryer be for the first time continuously regulated such, that the moisture content stays constant. Thus may be saved energy, because the amount of air to be blown and warmed to the drying hood may be minimized. At the same time the quality of paper will stay even because due to even moisture content of the air the edges, for example, dry the same way as the centre area of the web.

In an advantageous application of the invention radiation is transferred from a radiation source to detectors and back by means of conductors for which optical fibres are used. Optical fibres are for this use exceptionally suitable fibres through which radiation may be transferred efficiently from one place to another. By means of conductors radiation is possible to be transferred and aimed easily and reliably to weblike material and the radiation reflected and/or passed through may be transferred to detectors.

In the second advantageous application of the invention radiation is transferred from a radiation source to detectors and back by means of a lens system. A lens system designed for the purpose functions definitely and reliably.

In the next advantageous application of the invention as radiation sources semiconductor diodes radiating electromagnetic radiation are used. These are advantageous and while using these measurements of a whole web may be carried out across the whole web width advantageously and reliably. In other applications it is possible to use other, earlier recognized radiation sources, such as lasertype light source or for example X-ray tube.

In the next application of the invention as detectors semiconductor detectors are used. These detectors are advantageous and while using these measurements may be carried out across the whole web width advantageously and reliably. As semiconductor detectors recognized detectors such as Si-, InGaAs-, PbS-or MCT- detectors may be used.

In an application of the invention on the other side of weblike material mainly in cross directional position to it a supporting element is placed, where the conductors are laid. In another application on the opposite sides of weblike material mainly in cross directional position to it supporting elements are placed, where the conductors are laid. As supporting elements suitable for the occasion supporting constructions or supporting elements may be used, which may be relatively easily placed in needed distance from the material web or which are attached to it and to which conductors may be reliably attached.

In an advantageous additional application of the invention conductor heads near the material web are kept dry by conducting dry gas such as air round the heads by means of a fan. By means of dry compressed air heads are kept clean such that they conduct radiation efficiently and also receive it efficiently.

In the next advantageous application of the invention properties, such as moisture content, for example, are measured at more than one point of the paper web. In soft or super calender, for example, uneven moisture content may harm soft rollers.

Moisture has also influence on elasticity, plasticity and blackening of paper. It is of great importance to follow moisture profile on a calender, because paper dries more or less on a calender and often it must be dampened before calendering. For example, due to on-line super calendering technique which is coming to common use in the dry end of a paper machine at least three measuring bars are needed: measuring of moisture content before dampening, after dampening and after calendering i. e. final moisture content.

The measuring of moisture profile is one of the most important measurings in paper manufacture and the need for it is growing while speed on machines grows.

Moisture content measurements are going to be carried out at relatively more points in paper and coating machines as well as in calendering in the future than earlier.

The greater moisture content is the higher gloss is achieved but, correspondingly, opacity diminishes. In the same way smoothness gets better but bulk and stiffness get worse. Thus moisture content measurements may be used to optimize gloss/opacity and smoothness/bulk. Moisture content is also an absolute parameter in final paper because paper is sold due to its final use with certain moisture content and thus incorrect moisture content leads to reclamations. Costs of water in paper are negative, because raw material is almost free but dewatering it from paper costs as much as the energy needed to evaporate it.

In another application of the invention moisture profile is measured before and after a size press when the exact amount of water that stays in paper and the amount of dry clue is detected. So called pick-up of a size press i. e. the amount of wet clue stuck in paper and especially its profile are of great importance for the functioning of the process and quality of the final product. For the time being there are no commercial on-line measuring methods known for pick-up. Defects in final moisture profile are often created by uneven pick-up, but there can be no sureness while measuring method is not available.

Next, the invention will be explained in more detail with reference to the accompanying drawings, in which, Figure 1 illustrates an application of the equipment where paper web is measured by means of reflecting method, Figure 2 illustrates a principle drawing of another equipment according to the invention where fluoroscope method is used, and Figures 3 and 4 illustrate a principle drawing viewed from side.

In the application according to figures 1 and 2 there are schematically illustrated devices in the equipment and their position in regard to weblike material 1 (in the following paper web). In the application according to both of the figures radiation sources and detectors are placed outside a paper web and a processing device such as pressing part and/or a drying hood or another processing device. Radiation sources and detectors are placed in such space where circumstances for measuring

equipment to function reliably are sufficiently good. In this application radiation sources and detectors are placed in so called electronical box 2 in a separate space, and the details are not illustrated in figures 1 or 2. This electronical box is placed in a suitable place in distance from the place to be detected. It is also possible to place radiation sources and detectors in different places.

In the application according to figure 1 the equipment includes a bar 5, mainly crossdirectional with the paper web, functioning as a supporting element in this application, and placed in short distance from the paper web in the same space and optical fibre cables 3 laid from the electronical box 2 to the bar. In the figure there is only one optical fibre pair illustrated but in reality the quantity of fibres is not limited in any way but there may be hundreds of them or even more. Radiation sources and detectors are joined to the fibre cables in the electronical box, which has been laid to the bar 5. There is a longitudinal opening 7 in the side of the bar that points downwards to the material web and optical fibre cables are placed in the bar such that the heads of optical fibre cables point to the paper web. Heads of fibres may be spread into a wanted shape inside the bar.

In the application according to figure 2 the equipment includes bars 5, 6 mainly cross directional with the paper web functioning as supporting elements in this application, and placed in short distance from the paper web 1 in the same space such that one bar 5 is on one side of the paper web and the other bar 6 on the opposite side of the paper web. Also this application includes optical fibre cables 3, 4 laid from the electronical box to the bars. In the figure there is only one optical fibre pair illustrated but in reality the quantity of fibres is not limited in any way but there may be hundreds of them or even more. Radiation sources and detectors are joined to the optical fibre cables, which have been laid to openings 7 in bars such that the fibre cable heads point to the paper web.

In both applications the bars reach to the whole web width and even wider than the greatest width on both sides. Bar and/or bars and/or optical fibre cables and/or detectors may be placed fixed or movable to the equipment.

To the bars a pneumatic device or a corresponding device has been connected and it has been organized to blow compressed air inside the bar and round the fibres.

Compressed air is blown under suitable for the purpose pressure such as 0,5 bar.

Another pressure may also be used. Compressed air keeps the optical fibre heads dry and clean. Equipment includes, furthermore, a washing device, such as a

pressure washer, by means of which it is possible to wash and keep the optical fibre heads clean.

There are optical fibre heads along the whole length of bar/bars i. e. along the whole web width and some outside the web edge. As radiation source earlier recognized suitable for the purpose electromagnetic radiation sources are used and they are organized to radiate in earlier regocnized way. Correspondingly detectors are organized to receive and detect the radiation from the radiation sources in question.

As radiation sources NIR-, IR-and/or visible wavelength leds are used. Their energy need is small and operating time long. As detectors for example pure semiconductor diodes, such as silicon diodes, may be used.

While operating on the equipment according to figures and before starting the measurements reference measurement or measurements are carried out and thus the value of property to be measured inside the manufacturing device is detected and the equipment is calibrated taking into account this property value. The same way reference measurement or measurements are carried out to measure, for example, a disturbance due to water in the air or some other external factor by installing in one or more places near the web a system corresponding to the actual measurement such that the web is not between them. As earlier shown the moisture content of paper web is measured from the absorption peaks of water. For the measurement point of moisture content, for example, an absorption peak of water 1,94 um may be chosen and for the reference measuring point, for example, 1,8 um. Time between reference measurement and actual measurement may be, for example, about 10 microseconds.

Electromagnetic radiation is pulsed in a suitable way and thus disturbances due to external radiation are eliminated.

While operating on the equipment according to figure 1 radiation is transferred from a radiation source along fibre cables to a bar. In a bar a head of an optical fibre cable is laid to point at the paper web. Radiation sources are pulsed such that radiation occurs simultaneously across the whole web width. The radiation reflected from the paper web is measured or received by an optical fibre cable. The fibre cable transfers the radiation in question back to a detector in an electronical box, and the detector sends the gathered data further.

In the application according to figure 2 optical fibre cables have been laid both to a bar on one side of the paper web and to a bar on the opposite side of the paper web.

By means of the equipment the radiation passed through the paper web is measured and at the same time radiation reflected from the paper web is detected but in other parts functioning of the equipment corresponds to what earlier has been shown.

In figure 3 a measurement has been illustrated which is carried out continuously without pulsing, and 100% of web width and area in longitudinal direction is measured all the time. Measurement figure may be, for example, elliptical, spotlike or a line. In measuring measurement light sources 8 and reference light sources 9 are summed to the same point on the material web 1. As light sources in this application either LED or laser are used. On the measurement side two detectors 10 and 11 are used and before them there are band pass filters for the actual measurement (allows the wavelength 1,94 nm pass) and for reference (allows, for example, wave length 1,8 pm pass).

External disturbances may not have influence on this measurement because the measuring band is very narrow (smaller than 100nm, for example) on the both measuring frequencies and because by the reference measuring external disturbing radiation is diminished. Disturbing radiation may effectively be prevented by different kinds of protectors and/or filters.

In figure 4 there is another alternative illustrated, in which light source 8 is used which transfers such a wavelength band that it covers the measurement as well as reference frequency i. e. in practice 1,8... 2,0, um. Also in this case in measurement two detectors 10,11 are used and before them there are band pass filters for the actual measurement (allows the wavelength 1,94 llm pass) and for reference (allows, for example, wave length 1,8 llm pass).

Above there is the use of an equipment applying the method presented and measuring of a paper web named as the object, to which they perfectly are suitable.

The method in accordance with the invention may, however, be applied to measuring properties of other weblike materials as well.

The invention is not limited to the presented advantageous application but it can vary within the frames of the idea of the invention formed in the claims.