JP2007162204A - Dehydration foil with sensor, dehydration foil device and method for producing paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dehydration foil which has a sensor for embedded in a dehydration foil and can stably measure, by having an electrode keeping conductivity and excellent in abrasion resistance. <P>SOLUTION: A dehydration foil 4 is formed by directly embedding electrode 20, 30, 37 formed with a cermet composed mainly of titanium carbide and titanium nitride on the surface of a blade 2 comprising a ceramic of alumina (Al<SB>2</SB>O<SB>3</SB>) material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dewatering foil used in a dewatering section of a wire part of a paper machine, and in particular, a dewatering foil in which a sensor for measuring the concentration and white water weight of white water conveyed on a wire running on the dewatering foil is embedded. The structure of a dewatering foil with a sensor having an electrode having good conductivity and good wear resistance, a dewatering foil device using this dewatering foil with a sensor, and a paper manufacturing method using this dewatering foil device About.

  In the wire part of the paper machine, according to the on-top type as shown in FIG. 6, a large amount of water containing pulp from the stock inlet 500 is formed on the upper end side of the endless lower wire 101 that rotates and moves. The white water (paper material) 100 is continuously ejected. In the conveyance center part of the lower wire 101, an on-top device including a roller 150 is disposed, an upper wire 102 disposed in the same traveling direction is provided on the lower wire 101, and the white water 100 is formed by the lower wire 101 and the upper wire 102. The white water 100 is conveyed to the upper dewatering foil device 200 through the lower dewatering foil device 300 by the traveling of the upper and lower wires (twin wire portion 103).

  In the lower dewatering foil device 300 and the upper dewatering foil device 200 of the long mesh section from the stock inlet 500 to the upper dewatering foil device 200, a plurality of dewatering foils 400 that are long in the direction orthogonal to the wire traveling direction are spaced apart. While the wires 101 and 102 are running while adjusting (dehydrating adjustment) such as changing the height of each dewatering foil 400 to be arranged and flattening, the dehydration action (only pulp fibers remain and form a web) Is done.

  Although the wire part of the on-top type paper machine has been described with reference to FIG. 6, the long-form type that does not have an on-top device, and the gap former in which the twin wire portion that runs with white water sandwiched between the wires is vertically conveyed. Also in the dehydrating part of the wire part and the cover part of the suction box in the type, the dehydrating action is performed when the wire travels on the dehydrating foil.

  In the wire part, in order to obtain a sheet of good quality, it is necessary to set the sheet density of the white water 100 to an optimum density that matches the paper quality. However, since the white water 100 is transported and moved by the wire 101, the sheet density is After being discharged from the stock inlet 500, it is dehydrated by the respective dewatering foils 400, but has the property of constantly changing depending on the papermaking conditions.

  Therefore, in order to measure the sheet density and the white paper weight, a sensor is embedded at an appropriate position of the dewatering foil 400, and based on the data, adjustment of various conditions (raw material management) of the raw material supplied to the stock inlet 500, and at the time of conveying white water It has been proposed to adjust the water content of the white water 100 by adjusting the dehydration (dehydration management) of the lower dewatering foil device 300 in the long mesh part (see Patent Document 1).

JP-A-11-279979

As shown in FIG. 4, each dewatering foil 400 installed in the lower dewatering foil device 300 and the upper dewatering foil device 200 in the long net portion is elongated in a direction orthogonal to the wire conveying direction A. A plurality of segments 40 are arranged in series. The above-described sensor is attached to one segment 40 a constituting the long dewatering foil 400.
As shown in FIG. 4, the sensor has a base portion 41 made of a resin (insulating resin) as a main body, and a plurality of electrodes are arranged in the base portion 41 with a conductive stainless member. Thus, it is arranged in a packaged state in a segment 40a formed of ceramics. The electrode in the sensor includes a rectangular sensor electrode 42 and a ground electrode 43 arranged at a distance from the sensor electrode 42, and the ground electrode 43 has a circular electrode 44 at the center thereof.

  Then, when the wire 101 is conveyed from the back surface to the front surface in FIG. 5, the white water 100 is guided onto each of the electrodes, and the white water between the ground electrode 43 and the circular electrode 44 and between the ground electrode 43 and the sensor electrode 42. An electrical resistance of 100 is measured. The white water 100 dehydrated on the wire 101 generates a concentration gradient in the thickness direction of the white water (a high concentration on the wire side and a low concentration as the distance from the wire increases). By measuring the electrical resistance value of the high concentration portion formed in the vicinity of the wire by the ground electrode 43 and the circular electrode 44, the electrical resistance value of the entire white water thickness on the wire measured by the ground electrode 43 and the sensor electrode 42 is corrected. Do. By detecting such values, the change in the white water conductivity and the white water weight is calculated, and the conditions of the raw material supplied to the stock inlet 500 are adjusted and the dehydration is adjusted at the time of conveyance. The water content of white water is adjusted.

  However, according to the sensor having the above structure, since the wire 103 runs on the base 41 and the segment 40 (dehydration foil 400) on which the sensor is disposed, wear occurs in each electrode portion formed of stainless steel that comes into contact with the wire portion. However, there was a problem that the accurate measurement of electrical resistance was hindered.

  Further, since the sensor is mounted on the base part 41 as a package, the base part 41 made of resin also has irregularities, and the material of the segment 40a made of ceramic and the base part 41 made of resin ( Due to the difference in expansion coefficient, the resin expands and cracks occur on the ceramic side (segment 40a), which makes it difficult to perform stable measurement.

The present invention has been made in view of the above circumstances, and has a sensor-equipped dewatering foil-embedded dewatering foil and dewatering foil device capable of stable measurement by having an electrode with good conductivity and good wear resistance. It is intended to provide.
Furthermore, it aims at providing the method of manufacturing paper stably using such a dehydration foil apparatus.

  In order to achieve the above object, the dewatering foil with sensor (1) according to claim 1 is formed by directly embedding electrodes (20, 30, 37) formed of cermet on the surface of a blade portion (2) made of ceramics. It is characterized by. Various ceramics can be used for forming the blade part (2).

  According to a second aspect of the present invention, in the dehydrating foil with a sensor according to the first aspect, the cermet is mainly composed of titanium carbide and titanium nitride.

A third aspect of the present invention is the dewatering foil with a sensor according to the second aspect, wherein the cermet has a linear expansion coefficient of 7.0 to 7.5 × 10 ⁻⁶ / ° C. and a volume resistivity of 0.7 to 1.5 × 10 ^6. It is characterized by ^-4 Ω · cm.

According to a fourth aspect of the present invention, in the dehydrating foil with a sensor according to any one of the first to third aspects, the ceramic constituting the blade portion is a ceramic mainly composed of an alumina (Al ₂ O ₃ ) material. It is characterized by use.
As a result, the linear expansion coefficients of the electrode (20, 30, 37) formed of cermet and the blade portion (2) formed of ceramics mainly composed of alumina (Al ₂ O ₃ ) are set to substantially the same value. can do.

  According to a fifth aspect of the present invention, a dewatering foil apparatus is configured by mounting the dewatering foil with a sensor according to any one of the first to fourth aspects on a part of a long blade surface constituting the dewatering foil. It is characterized by.

  A sixth aspect of the present invention relates to a paper manufacturing method, in which the paper machine wire part is dewatered using the dewatering foil apparatus having the sensor-equipped dewatering foil according to any one of claims 1 to 4. It is characterized by doing.

According to the present invention, since the electrode (20, 30, 37) is directly embedded in the blade portion 2 formed of ceramics and the base portion (41) is not interposed as in the conventional example, the blade portion (2) It is possible to prevent the occurrence of cracks caused by the difference in materials in (ceramics).
And since an electrode (20, 30, 37) is formed with a cermet, it can be set as the linear expansion coefficient approximated to a braid | blade part (2), and generation | occurrence | production of abrasion and a crack can be prevented, ensuring electroconductivity. it can.

An example of a dewatering foil with a sensor according to an embodiment of the present invention will be described with reference to FIGS.
The dewatering foil with sensor 1 of the present invention is a sensor in which a sensor is directly embedded in a dewatering foil made of ceramics, and is externally the same as a single segment (segment 40 in FIG. 4) constituting a long dewatering foil. It is structured in size.
That is, the sensor-equipped dewatering foil 1 has a blade portion 2 made of ceramic as a main body, and a blade fixing member 3 is mounted on the lower side of the blade portion 2 to fix each blade of the segmented dewatering foil 1 and a plurality of segments. By attaching the member 3 to the long base 5 and arranging the blade surface so as to be continuous, the dewatering foil 4 that is long in the direction orthogonal to the wire transport direction A is provided (paper machine wire). A dewatering foil device can be formed which performs dewatering in part.

As the ceramic forming the blade part 2, the main component is any one of alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ), silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), and aluminum nitride (AlN). Although various ceramics configured as can be used, those having the properties of high electrical insulation, high corrosion resistance, high wear resistance, and high strength are preferable. In particular, in view of the relationship with the linear expansion coefficient of each electrode described later, it is preferable to use ceramics mainly composed of an alumina (Al ₂ O ₃ ) material. A ceramic mainly composed of an alumina (Al ₂ O ₃ ) material is constituted, for example, by containing impurities in 90 to 99.9% of the alumina (Al ₂ O ₃ ) material.
Then, by configuring the blade portion 2 with ceramics mainly composed of an alumina (Al ₂ O ₃ ) material, the linear expansion coefficient can be set to 6.8 to 7.3 × 10 ⁻⁶ / ° C. Further, the volume resistivity of the ceramic mainly composed of an alumina (Al ₂ O ₃ ) material is about (> 10 ⁻⁴ ) Ω · cm, and sufficient insulation can be ensured.

On the surface side of the blade portion 2, there are formed a rectangular groove portion 10 for embedding a sensor electrode, which will be described later, and a rectangular groove portion 15 for embedding a ground electrode at a distance from the rectangular groove portion 10.
The rectangular groove portion 10 is formed in a rectangular shape that is elongated in the direction along the traveling direction of the wire, and an electrode connecting hole portion 11 penetrating to the bottom surface side is formed at the bottom of the upper groove. The rectangular groove portion 15 is formed wider than the rectangular groove portion 10 at the same position as the rectangular groove portion 10 with respect to the traveling direction of the wire, and a central hole portion 16 penetrating to the bottom surface side is provided in the central groove bottom, and the lower right groove bottom Electrode connection holes 17 are formed.

A sensor electrode 20 formed of cermet is fitted in the rectangular groove 10 so as to be fitted. The sensor electrode includes a rectangular body 21 sized to fit into the rectangular groove 10 and a rod-like body 23 attached to a cylindrical groove 22 formed at the back corner of the rectangular body. The rod-shaped body 23 is attached to the rectangular body 21 by screwing the head of the rod-shaped body 23 or by fixing it with a conductive adhesive or melting.
A screw thread 24 is engraved around the rod-like body 23, and the tip of the screw thread 24 passes through the electrode connection hole 11 and protrudes from the back surface of the blade portion 2 when fitted into the rectangular groove portion 10. A signal line to the sensor electrode 20 can be connected to the protruding rod-like body 23.

  A ground electrode 30 formed of cermet is fitted in the rectangular groove 15 so as to be fitted. The ground electrode 30 includes a rectangular body 31 having a size that fits into the rectangular groove portion 15, and a rod-shaped body 33 that is attached to a cylindrical groove 32 formed at the back surface corner of the rectangular body 31. A screw thread 34 is engraved around the rod-shaped body 33, and the tip of the thread 34 penetrates through the electrode connecting hole 17 when being fitted into the rectangular groove 15, and is disposed so as to protrude from the back surface of the blade portion 2.

A hole 35 is formed at the center of the rectangular body 31, an annular body 36 made of ceramics is disposed in the hole 35, and a circular central electrode 37 is disposed inside the annular body 36. On the back side of the central electrode 37, a rod-like body 38 having a thread 39 engraved around is formed. The rod-like body 38 penetrates the central hole portion 16 and is disposed so as to protrude from the back surface of the blade portion 2. The rod-shaped body 33 is attached to the rectangular body 31 by screwing the head of the rod-shaped body 33 or fixing the rod-shaped body 33 with a conductive adhesive or melting.
A signal line to the ground electrode 30 or the central electrode 37 can be connected to the rod-shaped body 33 and the rod-shaped body 38 that are arranged to protrude from the back surface of the blade portion 2.

Since each of the electrodes 20, 30, and 37 is embedded in the blade portion 2 made of ceramic, the electrode is formed of a material having a linear expansion coefficient similar to that of the ceramic and having good conductivity. It is preferable.
When the blade part 2 is formed of a ceramic made of an alumina (Al ₂ O ₃ ) material, the linear expansion coefficient is 6.8 to 7.3 × 10 ⁻⁶ / ° C.

The present inventor has found that a cermet containing titanium carbide and titanium nitride as main components is suitable as an electrode material satisfying these characteristics.
That is, in order to prevent expansion of the blade portion 2 made of ceramics and to ensure conductivity as an electrode, titanium carbide (TiC) and titanium nitride (TiN) are used as cermets constituting the electrodes 20, 30, and 37. ) Is used as the main component. By using these materials, the linear expansion coefficient of the electrode can be set to 7.0 to 7.5 × 10 ⁻⁶ / ° C., and expansion to the blade portion 2 formed of ceramics can be prevented. Moreover, the volume resistivity of the electrode can be set to 0.7 to 1.5 × 10 ⁻⁴ Ω · cm to ensure the conductivity as the electrode.
In particular, when the blade portion 2 is formed of ceramics made of an alumina (Al ₂ O ₃ ) material, the linear expansion coefficient is 6.8 to 7.3 × 10 ⁻⁶ / ° C., so the linear expansion coefficient with the electrode (7.0 to 7.5 × 10 ⁻⁶ / ° C.) can be made substantially the same value, and the expansion of the electrode with respect to the blade portion 2 can be more effectively prevented.

When dewatering a paper machine wire part using a dewatering foil device when manufacturing paper, the above-described dewatering foil with sensor 1 is mounted as one of the segments constituting the long dewatering foil 4. it can.
That is, when the paper is manufactured using the dewatering foil apparatus having the sensor-equipped dewatering foil 1 configured as described above, a signal line is connected to each rod-like body 23, 33, 38 of the sensor-dewatering foil 1. By connecting, it can be used as a sensor for measuring the electrical resistance of white water on the wire conveyed on the dewatering foil. In this case, the relationship between the weight of water in white water and the electrical resistance is such that the electrical resistance decreases as the water weight increases, and conversely, the electrical resistance increases as the water weight decreases. The electrical resistance changes in proportion to the weight.

And the electrical resistance of the white water between the ground electrode 30 and the center electrode 37 in the dewatering foil with sensor 1 and the ground electrode 30 and the sensor electrode 20 is measured, and the change of the white water conductivity and the white water weight is calculated. Concentration change can be detected immediately, the cause is analyzed, the raw material management and dehydration management are performed by adjusting the various conditions of the raw material supplied to the stock inlet 500 and the dehydration adjustment at the time of transport, and transported by wire The water content of white water can be adjusted.
As a result, white paper with an appropriate sheet density is used to obtain a paper sheet with good quality, improved running performance due to reduced paper cutting during conveyance, and economic savings due to chemical savings when supplying raw materials to the stock inlet 500, etc. Improvements can be made.

It is a perspective explanatory view showing an example of implementation of a dehydration foil with a sensor concerning the present invention. It is a perspective explanatory view showing each component of a dehydration foil with a sensor concerning the present invention. It is side explanatory drawing which shows the assembly structure of the dehydration foil with a sensor which concerns on this invention. It is a perspective explanatory view of the conventional dehydrating foil with a sensor. It is a schematic diagram for demonstrating the measurement principle of the sensor of the dehydration foil with a sensor. It is structure explanatory drawing which shows the whole structure of the wire part in a paper machine.

Explanation of symbols

1 Dewatering foil with sensor (segment)
DESCRIPTION OF SYMBOLS 2 Blade part 3 Blade fixing member 4 Dehydration foil 5 Elongate base 10 Rectangular groove part 11 Electrode connection hole part 15 Square groove part 16 Central hole part 17 Electrode connection hole part 20 Sensor electrode 21 Rectangular body 22 Cylindrical groove 23 Rod-shaped body 24 Thread 30 Ground electrode 31 Rectangular body 32 Cylindrical groove 33 Rod body 34 Thread 36 Ring body 37 Central electrode 38 Rod body 39 Thread 40 Segment 41 Base part 100 White water (paper)
101 Lower wire 102 Upper wire 103 Twin wire 200 Upper dewatering foil device 300 Lower dewatering foil device 400 Dewatering foil 500 Stock inlet

Claims (6)

A dehydrating foil with a sensor, wherein an electrode made of cermet is embedded in the surface of a blade portion made of ceramics. The dehydrated foil with a sensor according to claim 1, wherein the cermet is composed mainly of titanium carbide and titanium nitride. 3. The sensor according to claim 2, wherein the cermet has a linear expansion coefficient of 7.0 to 7.5 × 10 ⁻⁶ / ° C. and a volume resistivity of 0.7 to 1.5 × 10 ⁻⁴ Ω · cm. Dehydrated foil. The dehydrating foil with a sensor according to any one of claims 1 to 3, wherein the ceramic constituting the blade portion is composed mainly of an alumina (Al ₂ O ₃ ) material. 5. A dewatering foil apparatus for a paper machine wire part, wherein the dewatering foil with a sensor according to any one of claims 1 to 4 is mounted on a part of a long blade surface constituting the dewatering foil. 5. A paper manufacturing method, comprising: dewatering a paper machine wire part using a dewatering foil apparatus to which the dewatering foil with a sensor according to any one of claims 1 to 4 is mounted.

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