JPH1123492A - Measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent entrance of dust into a cavity resonator, dew formation and damage of a sheet by sealing both openings of a slit in the cavity resonator with an non-oriented film and arranging a non-oriented resin block at the outer fringe of an opening. SOLUTION: A microwave is fed from the induction window 14 side of a cavity resonator Wn and the microwave transmitted through a sheet 01 is taken out from an induction window 15 and detected by means of a detector. In this regard, both openings 24 on the slit S side of the resonator Wn is sealed with a fluororesin film 220. The resin is non-oriented and has a low permittivity and causes no trouble in the measurement, e.g. anisotropy of the sheet 01. Furthermore, non-oriented fluororesin blocks 28 are arranged at the opposite outer fringe parts 26 in the longitudinal direction of the opening 24 and wound by the film 220 thus making smooth the corner at the fringe part 26. According to the structure, entrance of dust into the resonator Wn and dew formation thereof can be prevented and the anisotcopy distribution, the orientation, and the like, can be measured without damaging the sheet 01.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a film, paper, ceramics, plastic,
The present invention relates to a measuring device for measuring anisotropic distribution, orientation direction, dielectric constant, moisture content, and the like of a sheet such as a nonwoven fabric.

[0002]

2. Description of the Related Art Microwaves are radiated on sheets such as plastic films and papers, and the anisotropy distribution and orientation direction of the sheets can be measured by determining the microwave transmission intensity of these sheets. In this measurement, a slit is provided at the center of the cavity resonator, and a sheet is inserted into the slit. Here, if dust enters the cavity through the opening of the slit, the measurement accuracy is significantly reduced, and it is difficult to remove the dust inside the cavity. Further, when dew condensation occurs in the resonator, the dew condensation water absorbs the microwave. Of course, the performance of the resonator system decreases due to rust on the internal metal surface. Further, if the sheet is shaken due to vibration or the like during the measurement, the sheet inserted into the slit may touch the cavity resonator, and the sheet may be damaged at the outer edge of the opening.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent dust from entering the cavity and dew condensation in an apparatus for measuring the properties of a sheet by using microwave absorption. A secondary problem of the present invention is to perform measurement without damaging a sheet to be measured.

[0004]

According to the present invention, in a measuring apparatus for inserting a sheet into a slit provided at the center of a cavity resonator and detecting the absorption of transmitted microwaves of the sheet, a pair of non-oriented films is used to form the slit. It is characterized in that both openings are sealed. Preferably, a fluorine resin film is used for the non-oriented film.

[0005] A block of non-oriented resin is provided at the outer edge of the opening of the cavity resonator to prevent the outer edge from damaging the sheet. Preferably, a fluorine-based resin block is used for the non-oriented resin block.

[0006]

According to the measuring apparatus of the present invention, the sheet is inserted into the slit provided at the center of the cavity resonator. Therefore, the opening on the slit side of the cavity resonator is sealed with a non-oriented film to prevent dust from entering the cavity and dew condensation. Here, the non-oriented film is used.
For example, a fluorine-based resin film is used to enable measurement of orientation and the like. The fluororesin is non-oriented and does not hinder the measurement of the orientation of the sheet. Moreover, the dielectric constant is 2.
04 to 2.08, which is close to air, and the change in resonance frequency is small. Also, since the dielectric loss is extremely small at 10 ^-3 , microwave absorption is small. The thickness of the fluorine-based resin film is preferably as small as possible within the range of the strength, and the film can be sealed simply by pressing against the edge of the opening.

The sheet may shake during measurement due to vibration or the like, and the sheet may come into contact with the edge of the opening of the cavity resonator. If, for example, a fluororesin block is provided on the outer edge of the opening to smooth the corners of the edge, the sheet may be damaged by the edge of the opening even if the sheet is shaken and comes into contact with the edge. There is no. The reason why the fluororesin is used for the block at the outer edge of the opening is to prevent the influence on the sheet measurement such as changing the resonance frequency, etc., outside the cavity resonator but close to the slit. is there.

[0008]

1 to 3 show an embodiment. FIG. 3 shows a block configuration of the embodiment. Reference numeral 01 denotes a measuring sheet, for example, a plastic film, a plastic sheet, paper, a ceramic thin plate, or the like. These are oriented by stretching, papermaking, etc., and the orientation direction is film 01.
Is based on the flow direction (open arrow in FIG. 3), and differs depending on whether it is uniaxial stretching or biaxial stretching. As is well known, it is difficult to orient and stretch the sheet 01 uniformly, and the sheet 01 has a distribution in the orientation direction along the width direction and a distribution in the orientation direction along the longitudinal direction, though weaker than the width direction. Exists. Here, the sheet is passed through a plurality of cavity resonators provided in the longitudinal direction and the width direction of the sheet 01, and the strength of the different direction is obtained from the ratio of the transmitted microwave intensity along the longitudinal direction of the sheet 01, and the like. The distribution of anisotropic strength along the width direction of the sheet is also determined.

Reference numerals W1 to W6 denote cavity resonators. As shown in FIG. 1, each cavity Wn has a slit S through which a sheet 01 passes. Each cavity Wn has guide windows 14 and 15 on both sides of the slit S. For example, microwaves are supplied from the guide window 14 side, and microwave detectors D1 to D6 are arranged on the guide window 15 side. Then, the intensity of the microwave transmitted through the sheet 01 is detected. Although the guide windows 14 and 15 are small holes provided in the center of the orifice, a metal rod may be used instead of the orifice. The chain line in FIG. The cross-sectional shape of the cavity resonator Wn is a rectangle having an aspect ratio of 2 and has an electric field direction on the long-axis side of the cross section.

The angles of the cavity resonators W1 to W6 can be adjusted with respect to the sheet 01 within a range of, for example, about ± 30 degrees or ± 10 degrees, and R1 to R6 rotate the cavity resonators relative to the sheet 01. It is an adjuster for making it work. The directions of the cavity resonators W1 to W3 and W4 to W6 are substantially right angles, which means that the directions of the electric field of the microwaves are substantially right angles. Further, another cavity resonator W4 is provided behind the cavity resonator W1 along the flow direction of the sheet 01, and the cavity resonators W1 and W4 form a pair of cavity resonators near the left end. Similarly, a pair at the center of the sheet 01 is formed by the cavity resonators W2 and W5, and a pair near the right end of the sheet 01 is formed by the cavity resonators W3 and W6. Thus, a total of three pairs of cavity resonators are arranged near the center and both ends of the sheet 01.

In FIG. 3, reference numerals 2 and 4 denote oscillation circuits for supplying microwaves to the cavity resonators W1 to W6. Reference numeral 6 denotes a detection unit connected to the microwave detectors D1 to D6. The ratio of the signals from the detectors is output. A roller 8 sandwiches the sheet 01 between a pair of two rollers, that is, a total of four rollers, and positions the sheet 01 so that the sheet 01 flows through the center of the slit S. A pair of rollers 8 is provided before and after the cavity resonator Wn so that the sheet 01 is firmly sandwiched to reduce the blur. Reference numeral 10 denotes a motor for driving the roller 8, and reference numeral 12 denotes a control unit of the entire measuring apparatus. In this embodiment, the roller 8 sandwiches the sheet 01 from above and below to prevent the sheet 01 from moving, but the roller 8 may also be used for sheet feeding.

FIG. 1 shows a cavity Wn for a sheet 01.
In this arrangement, microwaves are supplied from the guide window 14 side, and microwaves that are not absorbed by the sheet 01 and transmitted therethrough are extracted from the guide window 15 and detected by the detector Dn. The adjusters R1 to R6 are composed of two parts, an upper adjuster Rnu and a lower adjuster Rnl in FIG.
nl is attached to the cavity resonator Wn and rotates synchronously. The regulators Rnu and Rnl are mounted on dies 16 and 17, for example, the three cavity resonators of FIG. 1 are mounted on a common die. Therefore, two sets of dies 16 and 17 are provided in the case of FIG. Reference numerals 18 and 19 denote stepping motors, which are operated by a signal from the control unit 12, and which operate on the upper stepping motor 1
8 and the lower stepping motor 19 rotate by the same rotation angle, and the regulators R1 to R6 rotate in principle synchronously. As a result, the orientation of the two cavity resonators in each pair is always kept substantially perpendicular. In addition, the three cavities W1, W2, and W3 on the upstream side along the flow direction in FIG. The direction is adjusted only by the angle. Similarly, the cavity resonators W4, W5, and W6 (referred to as the second row of cavity resonators) also rotate by the same angle while maintaining a common orientation. Cavity resonators W1 through regulators R1 through R6
The rotation range of W6 is, for example, ± 30 degrees or ± 10 degrees, and the rotation angle is set so that the ratio of the two transmitted microwave intensities in the same pair is maximized. This setting is performed when the measuring device is adjusted, and the directions of the cavity resonators W1 to W6 are fixed between the adjustments. Reference numerals 20 and 21 denote gears for reducing the rotation speed of the stepping motors 18 and 19 to rotate the adjuster Rn.

Reference numeral 22 denotes a fluororesin film sealed in the opening 24 on the slit S side of the cavity resonator Wn. Examples of the fluorine-based resin include polytetrafluoroethylene and tetrafluoroethylene-hexafluoropropylene copolymer. These are non-oriented and have a dielectric constant of 2.
It is as small as 04 to 2.08 and extremely small with a dielectric loss of 10 ^-3 or less. For this reason, the microwave absorption by the film is small, the resonance frequency is not changed, and the measurement of the sheet anisotropy or the like is not hindered. The thickness of the film is preferably as small as possible within the range allowed by the strength, and for example, is preferably from 30 to 100 μm. In addition, the fluorine resin film 22 has an opening 24.
Can be sealed simply by pressing against the edge 26 of Of course, it may be attached to the outer wall portion of the cavity resonator Wn with a tape or the like.

[0014] In addition to fluorine-based resins, polyesters can be used as a material capable of forming a non-oriented film. Polyester has a dielectric constant of 2.8 to 3.0 and a dielectric loss of 0.012.
Approximately 0.025, all of which are larger than the fluororesin. Therefore, a fluororesin film is most preferable.

FIG. 2 shows another embodiment. 28 is the opening 2
4 is a non-oriented fluororesin block provided on the outer edges 26 at both ends in the longitudinal direction. In addition to the non-oriented fluorine-based resin block, a block of polyester or the like may be used.
Reference numeral 220 denotes the same fluororesin film for sealing the opening 24 as in the first embodiment. The fluororesin blocks 28 on both sides of the edge 26 are wound around the opening 2.
4 is sealed. Here, the fluororesin film is pressed and sealed to the fluororesin blocks 28, 28, but may be fixed with, for example, a tape. Fluorine resin block 2
Reference numeral 8 denotes a shape in which the corners of the edges 26, 26 are smooth, and is fixed to the edge 26, for example. Preferably, a gap is provided between the fluorine-based resin block 28 and the outer surface of the cavity Wn, and the film 220 is sandwiched between the gaps. Further, a pair of fluorine resin blocks 28 are provided at both ends in the longitudinal direction of the cavity resonator Wn at right angles to the sheet flow direction. Therefore, the sheet 01 flows without being damaged. In this embodiment, the cavity resonator Wn
, A total of two rollers 80 in the upper and lower directions are arranged diagonally.

The operation of the embodiment will be described.
The microwave from 4 is supplied to the cavity resonators W1 to W6, and after being absorbed by the sheet 01, the transmitted microwave is detected by the detectors D1 to Dn. Here, the ratio of the signals of the two detectors in each pair is determined by the orientation direction of the sheet 01 at that position, and if the sheet 01 is uniform along the width direction, the detection of the ratio of the three pairs is performed. The signal is constant. On the other hand, if there is a distribution in the alignment direction along the width direction of the sheet 01, the detection signal of the ratio of the three pairs fluctuates. The detection signals of the three ratios are obtained by a divider (not shown) in the detection unit 6, and the anisotropic distribution of the sheet 01 can be obtained therefrom.

In order to accurately detect the transmitted microwave, the inside of the cavity Wn must be clean. However, dust floating in the air may actually enter the cavity Wn and form dew inside the cavity Wn. Dust and dew increase microwave absorption in the cavity resonator Wn, change the resonance frequency, and hinder measurement. Therefore, the fluororesin films 22 and 2
If the opening 24 of the cavity resonator Wn is sealed with 20, it is possible to prevent intrusion and dew condensation of dust and the like. Moreover, the fluororesin films 22 and 220 are non-oriented, have a small relative dielectric constant, and extremely small dielectric loss. Further, it can be easily attached to the opening 24.

The position of the sheet 01 is determined by the rollers 8 and 80, blurring due to vibration or the like is prevented, and the sheet 01 flows in a substantially central portion of the slit S stably. Therefore, the orientation measurement of the sheet 01 can be accurately performed without damaging the sheet 01.
If the sheet 01 is shaken, it easily contacts the edge portion 26 and may be cut off. Thus, the rollers 8 and 80 are used to prevent the sheet 01 from being shaken, and the fluororesin blocks 28 and 28 are provided on both sides of the edges 26 to smooth the corners.
As a result, the sheet 01 is not damaged. Further, the fluororesin block 28 is also non-oriented similarly to the sheets 22 and 220, has a small relative dielectric constant and a small dielectric loss, and does not disturb the measurement data. In the example, the anisotropic distribution and orientation of the sheet 01 were measured, but the present invention is not limited to this.

[Brief description of the drawings]

FIG. 1 is a block diagram of an apparatus for measuring anisotropic distribution according to an embodiment.

FIG. 2 is a partial cross-sectional view of an apparatus for measuring anisotropic distribution according to an embodiment.

FIG. 3 is a partial cross-sectional view of an apparatus for measuring anisotropic distribution according to another embodiment.

[Explanation of symbols]

 01 Film 2,4 Oscillation circuit 6 Detector 8,80 Roller 10 Motor 12 Controller 14,15 Induction window 16,17 Die 18,19 Stepping motor 20,21 Reduction gear 22,220 Fluorine resin film 24 Opening 26 Edge Part 28 Fluorine-based resin block W1 to W9 Cavity resonator S Slit D1 to D6 Microwave detector R1 to R6 Cavity resonator adjuster

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kunio Murata 33-30 Koyamame Kamiyamacho, Nishinomiya, Hyogo

Claims (4)

[Claims] 1. A measuring apparatus for inserting a sheet into a slit provided at the center of a cavity and detecting a transmitted microwave of the sheet, wherein both openings of the slit are sealed with a pair of non-oriented films. A measuring device, characterized in that: 2. The measuring device according to claim 1, wherein the non-oriented film is a fluororesin film. 3. The method according to claim 1, wherein a block of non-oriented resin is provided at an outer edge of the opening of the cavity resonator to prevent the sheet from being damaged by the outer edge of the opening. measuring device. 4. The measuring apparatus according to claim 3, wherein said non-oriented resin block is a fluorine resin block.