FIELD OF THE INVENTION

The present invention relates to a fabric for a paper or pulp technology. The fabric has a longitudinal direction and a cross direction and a first surface and a second surface in a thickness direction of the fabric. The fabric extends in the cross direction from a first edge to a second edge. The present invention also re lates to a method for manufacturing a fabric for a paper or pulp technology.

BACKGROUND OF THE INVENTION

One of the challenges associated with the known fabrics for a paper or pulp machine is that measurement results from the real conditions prevailing in the process are required in order to adjust the process. There are known measure ment devices but they are often either handheld devices, or measurement bars. The handheld devices form a substantial danger for employees since they have to work in a close proximity of fast running webs and rolls. Besides the above-mentioned devices, measurement sensors placed in a paper machine roll are also known. A common problem to all options is that there are no measurement methods for all interesting parameters. Furthermore, there is no measurement methods for meas uring inside a fabric.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is thus to provide a fabric and a method so as to solve the above problems. The objects of the invention are achieved by a product and a method which are characterized by what is stated in the inde pendent claims. The preferred embodiments of the invention are disclosed in the dependent claims.

The invention is based on the idea of embedding an adaptable medium comprising at least one sensor in a fabric in order to get data from inside of the fabric, from the surface of the fabric, or from a close proximity of the fabric.

The fabric is for a paper or pulp technology, such as for a paper or pulp machine, or for filtration related to the paper or pulp technology, e.g. disk filters. The fabric may be a wire or a felt. The fabric is especially a felt for a press section. The felt for a press section comprises at least one fabric and at least one batt fiber layer. The felt may be impregnated with polyurethane. The impregnation may be so intense that the air permeability of the felt may be almost zero. The felt may have to operate at a speed of 50 to 2200 m/min. The pres sure in a nip, which the felt passes, may be, for example, 1 to 3 MPa, 2 to 5 MPa, 3 to 6 MPa, or 7 to 10 MPa.

The fabric has a longitudinal direction and a cross direction. The fabric may be an endless loop, or the fabric may extend in the longitudinal direction from a first end to a second end. The fabric extends from a first edge to a second edge in the cross direction of the fabric. The fabric has a first surface and a second surface in the thickness direction of the fabric.

The fabric may comprise more than one base fabric one upon the other. The base fabrics may have different structures.

In use in a papermaking machine or a like, the fabric runs as an endless loop through nips formed between rolls of the papermaking machine. The running direction of the fabric is the longitudinal direction of the fabric. Conditions prevail ing in the nips are often of interest. The fabric comprises an adaptable medium comprising at least one sen sor. The adaptable medium means in this text a deformable structure that adapts to the fabric where it is inserted. The adaptable medium may be a string comprising at least one sensor, or a sheet comprising at least one sensor. The adaptable me dium may comprise more than one sensor and the fabric may contain several adaptable media. Each sensor may not measure the same parameter but there may be sensors that measure various parameters. The string may be an elongated ob ject, such as a yarn, a band, a fiber, or a filament provided with at least one sensor. The string may be of any suitable material. The string may be, for example, of metal or plastic. It is also possible that the string comprise more than one material. The string may be e.g. a metallic filament covered by a plastic sheath. The sheet may be, for example, a fabric, a net, or a membrane. The sheet may be water permeable.

The string may extend in the fabric in the longitudinal direction, in the cross direction, or randomly. The length, which the string extends in the fabric, is selected case by case. For example, the string may extend from one edge of the fab- ric to the other edge in the cross direction of the fabric, or a certain length in the cross direction. According to another example, the string may extend almost indef initely in a fabric having a form of an endless loop.

The string may have a width or a diameter of less than three millime tres, for example from 1 to 3 millimetres, or 0.5 to 3 millimetres, or 0.1 to 3 milli- metres. The sheet may have a thickness of less than three millimetres, for example from 1 to 3 millimetres, or 0.5 to 3 millimetres, or 0.1 to 3 millimetres. The sensor may be attached on the surface of the adaptable medium, or it may be inside the adaptable medium. The sensor may measure various parame ters in the fabric, such as temperature, temperature profile, wear, volatile organic compounds (VOC), humidity, pH, microbial level, organic and inorganic material content, dirt content, flow rate and flow velocity field, or pressure in a nip. The size of the sensor may be a few square millimetres or smaller, or it may be larger, e.g. a few square centimetres. In case of a larger sensor it must be at least partially water permeable. It is possible that the sensor is a printed circuit printed on a textile sur face, or the sensor is a strain gauge. The sensor is configured to transmit wirelessly gathered measurement results to an external receiver. The sensor may use an antenna for transmitting data to the receiver. The measurement results may be stored in a cloud service. A user may receive the data e.g. into a mobile phone. The data may be available through the internet via a suitable software. The wireless data transmitting may be based on the radio frequency identification (RFID). Among the RFID techniques the near field communication (NFC) is of interest.

The fabric comprises machine direction yarns in the longitudinal direc tion and the string may be configured to extend in the machine direction. The string may be a machine direction yarn of the fabric, or it may be a separate yarn extend- ing in the machine direction. The latter may come into question especially when the string is assembled into a ready-made fabric.

The fabric comprises cross direction yarns in the cross direction and the string may be configured to extend in the cross direction. The string may be a cross direction yarn of the fabric, or it may be a separate yarn extending in the cross di- rection. The latter may come into question especially when the string is assembled into a ready-made fabric.

The string may be configured to extend diagonally to the longitudinal direction and the cross direction of the fabric, or at any angle to the longitudinal direction and the cross direction of the fabric. In this case, the string is usually as- sembled in a ready-made fabric.

The fabric may comprise seam loops at the first end and the second end and the string may be configured to extend inside the seam loops in the cross di rection of the fabric.

The fabric may comprise at least one batt fiber layer. The batt fiber layer may be on the first or second surface of the fabric or on both surfaces. The string may be configured to extend inside the batt fiber layer. The fabric may comprise more than one fabric layer and the batt fiber layer may lie between the fabric layers. The batt fiber layer may also lie on one of the outer surfaces or on both surfaces. The string may be configured to extend in side at least one batt fiber layer. The fabric may comprise layers of machine direction yarns one upon the other in the thickness direction of the fabric and the string may be configured to extend between the layers of the machine direction yarns.

The string may be configured to extend at least partially in the thickness direction of the fabric. The fabric may comprise a sheet provided with at least one sensor.

The string may be assembled in the fabric during manufacturing of the fabric, or to a ready-made fabric. The string may be assembled in a ready-made fabric e.g. by a needle which may be straight or curved. The string is threaded through the eye of the needle and the string is darned inside the fabric by the nee- die. Further, such techniques such as sewing, injecting, gluing, weaving, winding, or printing may be used.

The string may be assembled inside the seam loops parallel to a pin connecting the seam loops, or the string may be the pin connecting the seam loops. The string may be inserted in the channel of intermeshed seam loops by a tool. The tool may be configured to thread the string, or shoot or inject the string inside the channel.

The string may have a water soluble sheath which protects the sensor during manufacturing of the fabric. The sheath dissolves in water when the fabric is in use in the papermaking machine, thus revealing the sensor for gaining data. The string may be added to the fabric so that one or more strings are added in a liquid and the liquid is spread to the fabric, thus applying the sensors to the desired area of the fabric. The strings may be fixed to the fabric e.g. by needling or curing.

The sensor may work by an energy harvester, such as a kinetic energy harvester. The kinetic energy harvester changes kinetic energy to electric energy, which the sensor utilizes as an electric power source. The kinetic energy harvester may extract electrical power by employing one or a combination of different trans duction mechanisms. Main transduction mechanisms are piezoelectric, electro magnetic and electrostatic mechanisms. The utilized kinetic energy may be, for ex- ample, vibrations of the running fabric. Another option is that the sensor works by electric power, which is created by a magnetic field arranged outside the fabric. The magnetic field may be created, for example, by the receiver. Further, a dry-cell bat tery or a rechargeable battery may be used as a power source.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which

Figure 1 is a perspective view of a fabric and a system related to it,

Figure 2 is a view of a fabric from above,

Figure 3 is a side view of a fabric, Figure 4 is a side view of a part of a fabric,

Figures 5 to 7 are perspective views of a fabric.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a schematic view of a fabric 1. The fabric has a longitu dinal direction MD, a cross direction CMD, a first surface FS and a second surface SS. The fabric 1 extends in the cross direction from a first edge 7 to a second edge 8. The fabric 1 forms in the machine direction MD an endless loop as shown in Fig. 1.

The system related to the fabric 1 may comprise a reader 20, a computer 21 and a cloud service 22. The reader 20 reads measuring results which are stored in a cloud service 21 and processed by a computer 22.

Figures 2 and 3 show schematic views of a fabric 1. The fabric has a lon gitudinal direction MD, a cross direction CMD, a first surface FS and a second sur face SS. The dryer fabric 1 comprises a weave 2 and seam forming counterparts 3, 4. On one of the outer surfaces of the weave 2, or on both outer surfaces of the weave 2 may be a batt fiber layer (Figs. 6 and 7). The batt fiber layer may also be between two weaves 2 when the fabric 1 comprises more than one weave 2 one upon the other.

The weave 2 comprises a first end FE, a second end SE, a first end region FR, a second end region SR, a first edge 7 and a second edge 8. When the fabric 1 is in use in a paper or pulp machine the seam forming counterparts 3, 4 are joined together by a pin 10 (Fig. 4).

Figure 4 shows a cross section of the fabric 1 at the seam forming coun terparts 3, 4. The seam forming counterparts 3, 4 are seam loops. The seam loops of the first end FS and the seam loops of the second SE alternate in the seam in such a manner that a channel 9 forms in the cross direction CMD of the fabric 1. The pin 10 threaded into the channel 9 joins the ends FE, SE together.

The pin 10 may comprise a sensor, i.e. the pin 10 is a string comprising at least one sensor. Alternatively, there may be a conventional pin in the channel 9, which is accompanied by one string comprising one or more sensors, or more strings each comprising one or more sensors. The string may have a length, which corresponds the whole width of the fabric, or the string may be shorter.

There may be a specific tool for inserting the string inside the channel 9. The tool may be configured to thread the string, or shoot the string inside the channel 9. Figure 5 shows the fabric 1 in a schematic perspective view. Fig. 5 shows how the strings may lie in the fabric 1. The fabric may comprise the spiral fabric 20 or the weave 2. The same fabric 1 may comprise several strings either assembled in the same manner or differently. Further, the same fabric 1 may be provided with strings 16 of Fig. 6 or a sheet 17 of Fig. 7. The string 11 extends in the cross direction CMD. The string 11 itself may be a cross directional yarn of the fabric 1, or a separate string extending in the cross direction. The separate string may be assembled in the fabric 1 by adding it to the same shed with a weft yarn during weaving of the fabric 1, or it may darned into the fabric 1 in a suitable phase after manufacturing. It is also possible that the string 11 is added to the fabric 1 at a paper or pulp machine during a stoppage.

The string 12 extends in a diagonal direction in the fabric 1. The string 12 may darned into the fabric 1. The string 12 may be at any angle to the longitu dinal direction MD and the cross direction CMD of the fabric 1.

The string 13 extends in the longitudinal direction MD. The string 13 itself may be a longitudinal yarn of the fabric 1, or a separate string extending in the longitudinal direction. The separate string may be assembled in the fabric 1 by darning it into the fabric 1 in a suitable phase after weaving. It is also possible that the string 13 is attached to a warp yarn so that it passes the same reed spacing as the warp yarn during weaving. Further, the string 13 may be added to the fabric 1 at a paper or pulp machine during a stoppage.

The string 14 extends partially in the thickness direction of the fabric 1. The string 14 may be added to the fabric 1 by darning.

The fabric 1 may comprise two longitudinal yarn layers one upon the other in the thickness direction TD of the fabric 1. Fig. 5 shows schematically the locations of the first longitudinal yarn layer FW and the second longitudinal yarn layer SW. The string 15 extends between the first longitudinal yarn layer FW and the second longitudinal yarn layer SW in the cross direction CMD of the fabric 1.

The fabric may comprise more than two longitudinal yarn layers one upon the other. There may be e.g. 2 to 5 yarn layers. Further, it is also possible that there are more than one layer of cross machine direction yarns. The string 15 may extend between each superimposed layers, or between some of the superimposed layers.

Figure 6 shows a schematic perspective view of the fabric 1. The fabric 1 comprises a batt fiber layer BFL on the first side FS of the fabric 1, i.e. the fabric is a felt. The felt may be used in a press section of a paper or pulp machine. The string 16 may be one of the fibers of the batt fiber layer BFL. The string 16 may be assembled into the fabric 1 by needling. The string 16 may be randomly oriented, or it may extend e.g. in the longitudinal direction MD of the fabric 1. The string 16 may extend in the longitudinal direction of the fabric 1 in a predetermined location in such a manner that it is possible to needle the batt fiber layer BFL to the weave in such a manner that the at least one sensor remains undamaged.

Figure 7 shows another schematic perspective view of the fabric 1. The fabric 1 may comprise a sheet 17 under the batt fiber layer BFL. The sheet 17 may cover the whole surface of the fabric 1, or only partially. The sheet 17 may be a fabric, a net, or a membrane. The sheet may be water permeable. The sheet 17 com- prises one or more sensors.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The inven tion and its embodiments are not limited to the examples described above but may vary within the scope of the claims.