JPS58190751A - Apparatus for measuring water content - Google Patents

Abstract

PURPOSE:To make it possible to measure water content accurately and rapidly even if the thickness of a sample is different, by providing such constitution wherein one electrode has a signal electrode or an earth electrode while the other one has the earth electrode. CONSTITUTION:A signal electrode 11 is fixedly attached to an electrode support member 13 comprising an electric insulating material so as to position earth electrodes 12 to both sides of said signal electrode 11 to constitute one electrode 14 and an opposed earth electrode 15 is fixedly attached to electrode support members 16 to constitute the other electrode 17 while an object 18 to be inspected is arranged so as to be held between the signal electrode 11, the earth electrode 12 and the earth electrode 15 and one end of a high frequency capacity meter 20 is connected to the signal electrode 11 through a shield wire 19 while the other end of the high frequency capacity meter 20 is connected to the earth electrode 12 and the earth electrode 15 through a shield wire 12 and the electrostatic capacitiy of the sample 18 is measured to measure water content.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a moisture content measuring device for measuring the moisture content of a specimen such as paper, fibers, hair, etc., and in particular, even if the thickness of the specimen is different, the moisture content of the specimen can be measured even if the thickness of the specimen is different. The present invention relates to a moisture content measuring device that can accurately and quickly measure moisture content.

Generally, the relationship between dielectric constant and water content is expressed by the following approximate formula. That is, ε-εQ=KM However, ε is the dielectric constant of the material at the water content M, ε0 is the dielectric constant specific to the material, and is a constant determined by the material.

Therefore, by measuring the change in the dielectric constant of the material at the moisture content M, the moisture content can be calculated.
For this purpose, it is sufficient to measure the capacitance of the material at the moisture content M under the same measurement conditions.

Conventionally, in view of the points mentioned above, a moisture content measuring device has been proposed that measures the capacitance of a test object using high frequency waves and measures the water content of the test object. As shown in FIG. 1, a subject 3 is sandwiched between a signal electrode 1 and a ground electrode 2, a high frequency capacitance meter is connected between the signal electrode 1 and the ground electrode 2, and the high frequency capacitance meter is used to detect the subject 3. 3, and the moisture content of the subject 3. As shown in FIG. The specimen 3 is pressed against the specimen 3, a high frequency capacitance meter is connected between the signal electrode 1 and the earth electrode 2, and the electrostatic capacitance of the specimen 3 is measured by the high frequency capacitance meter, and the water content of the specimen 3 is measured. It is composed of

Test object 3 when the total capacitance of paper as test object 3 was measured using the moisture content measuring device configured as shown in Fig. 1 above.
Figure 3 shows the relationship between the thickness and capacitance of the specimen 8.
Figure 4 shows the relationship between the thickness of the object 3 and the capacitance when measuring the capacitance of paper.
As is clear from FIGS. 1 and 4, if the moisture content measuring device is configured as shown in FIGS. ,
Therefore, there was a drawback that the water content of the subject 3 could not be measured accurately.

The present invention relates to a moisture content measuring device that eliminates the above-mentioned drawbacks.

An embodiment of the moisture content measuring device of the present invention will be described below with reference to FIGS. 5 and 6.

The moisture content measuring device of the present invention is fixed to an electrode support member 13 consisting of a signal electrode II and a ground electrode + 2i electrical insulators so that the ground electrodes 12 are located on both sides of the signal electrode 11, as shown in FIG. to form one electrode 14, and the ground electrode 15 facing the signal electrode 11 and the ground electrode 12 of the one electrode 14 is connected to the electrode support member +6.
i/i1m is fixed to form the other electrode 17, and the one electrode 14 and the other electrode]7 are connected to the signal electrode I+ of the one electrode 14 and the ground electrode 12 and the ground electrode 15 of the other electrode 17. The object 18 is placed in between, and one side of the high frequency capacitance meter 20 is connected to the signal electrode 11 of the one electrode 14 through the entire Nord wire 19, and the ground electrode 12 of the one electrode 4 and The other side of the high-frequency capacitance meter 20 is fully connected to the ground electrode 15 of the other electrode 17 via the shield wire 21, and the high-frequency capacitance meter 20 measures lj,
, l-Measure the capacitance of the object I8, and measure the capacitance of the object I8.
The device is designed to measure the water content of

In addition, in the above configuration, one electrode 14 and the other electrode]
The structure of 7 is not limited to the above embodiment, and for example, as shown in FIG. The electrode 12 is fixed to the electrode support member 13 as shown in FIG. 9, and the one electrode 14
The other electrode 17 having a ground electrode 15 facing the signal electrode 11 and ground electrode 12 is configured as shown in FIG. 8, and the one electrode 14 and the other electrode 17 are configured as shown in FIG. The subject 18 may be placed between the ground electrode 12 of one electrode I4 and the ground electrode I5 of the other electrode 17, and one electrode 14 may be placed between the ground electrodes 12 and 15 of the other electrode 17. As shown in the figure, a circularly formed signal electrode 11 is surrounded by an annular ground electrode 12, the ground electrode 12-i is surrounded by an annular signal electrode 11, and the signal electrode 11 is further surrounded by an annular ground electrode 12. 11 and a ground electrode I2 are fixed to an electrode support member 13 as shown in FIG. The electrode 15 is configured as shown in FIG. 11, and the other electrode 17 is configured as shown in FIG.
The subject 18 is sandwiched between the signal electrode 11 and the ground electrode 12 of the one electrode J4 and the ground electrode 15 of the other electrode I7, as shown in FIG. The signal electrodes 11 and the ground electrodes 12 may be placed in the 15th position so that the ground electrodes 12 surround the plurality of signal electrodes II, with one electrode 14 placed in the 15th position as shown in FIG. As shown in the figure, it is configured to be fixed to an electrode support member 13, and the one electrode 1
The signal electrode II of 4 and the other electrode 17 having a rectangular shape opposite to the ground electrode 12 are arranged as shown in FIG. 17 may be arranged so that the subject 18 is sandwiched between the signal electrode i11 and the ground electrode 12 of one electrode 14 and the ground electrode 15 of the other electrode 17, as shown in FIG. One electrode I4 is connected to a plurality of signal electrodes 1 as shown in FIG.
The signal electrode 11 and the ground electrode 12'f are fixed to the electrode support member 13 as shown in FIG. FIG. 18 shows the other electrode 17 having a ground electrode 15 provided with an electric insulator spacer z'2 made of a homogeneous acrylic resin flat plate of a predetermined thickness as shown in FIG. 17 on the surface facing the ground electrode I2. The one electrode 14 and the other electrode I7 are arranged as shown in FIG.
As shown in Figure 8, the signal electrode II of the one electrode I4
and the earth electrode 15 of the earth electrode 12 and the other electrode 17
The subject 18 may be placed between the spacer Z and the spacer Z.

In addition, in the above-mentioned FIGS. 7 to 18, FIG.

Figures 1θ, 13, and 16 are plan configuration diagrams of one electrode I4, and Figures 8, 11, 14, and 1
7 is a back view of the other electrode 17, and FIGS. 9, 12, 15, and 18 are views of one of the electrodes 14 in FIGS. 7, 10, 13, and 16. The cross section taken along line xx' and Fig. 8, Fig. ! (2) A cross section of the other electrode 17 taken along line X-x' in FIGS. 14 and 17, showing one electrode 4 and the other electrode 17 facing each other.

FIG. 19 shows the relationship between the thickness of the specimen 3 and the capacitance when measuring the capacitance of paper as the specimen 18 with the configuration of the moisture content measuring device of the present invention shown in FIG. As is clear from FIG. 19, if the thickness of the object 18 is within a certain range (the thickness is about 1 inch thick), the capacitance is constant.

In this way, when using the water content measuring device of the present invention shown in VC FIG. 6, it is possible to
(within a certain thickness of the object 18)
8 capacitances can be measured.

FIG. 20 is a diagram showing the relationship between capacitance and water content calculated by calculating the water content of the subject 18 based on the measurement results shown in FIG. 19 above.

As described above, according to the moisture content measuring device of the present invention, the capacitance of the subject 18 depends on the thickness of the subject 18 (within a certain thickness of the subject 18). This is extremely meaningful because it can be measured and the moisture content of the subject 18 can be calculated from the results.

In addition, in the measurement of capacitance in the above embodiment, the frequency I
Although a high frequency of MHz was used, a frequency of 100 KHz or 10
High frequencies such as MHz can be used as well.

Since the moisture content measuring device of the present invention has the above-described configuration, it is possible to accurately and quickly measure the moisture content of the specimen even if the thickness of the specimen is different, and without destroying the specimen. Furthermore, since the signal electrode can be provided on one side, the structure can be made simpler than when the signal electrode is provided on both sides.

[Brief Description of the Drawings] Figures 1 and 2 are configuration diagrams of the electrodes and specimen of a conventional water content measuring device, and Figures 3 and 4 are diagrams of the conventional water content measuring device. A diagram showing the relationship between the capacitance and thickness of a water content measuring device, FIG. 7 to 18 are schematic diagrams of other embodiments of the electrodes of the water content measuring device of the present invention. FIG. 20 is a diagram showing the relationship between capacitance and water content based on the measurement results of FIG. 19. In the drawings, 11 is a signal electrode, 12.15 is a ground electrode, 14 is one electrode, and 17 is the other electrode. Agent Patent Attorney Aihiko Fukushi (Y4) 1mm (mm) 3rd-Ami (mm) llS4Figure 15 Figure 8 Figure 10 Figure 12 J Figure 9 Figure 1I Figure 1314 4mm (mm) ) Figure tq includes f (years) Figure 20-29 (

Claims (1)

[Claims] 1. In a moisture content measuring device that measures the capacitance of the specimen by sandwiching the specimen between electrodes and applying high frequency between the electrodes to measure the water content of the specimen, one of the electrodes is 1. A water content measuring device comprising a signal electrode and a ground electrode, the other of which is a ground electrode.