JPS6218866B2 - - Google Patents

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, fiber, hair, etc., and in particular, it is capable of accurately measuring the moisture content of the specimen even if the thickness of the specimen differs. The present invention also relates to a moisture content measuring device that can quickly measure moisture content.

Generally, the relationship between dielectric constant and water content is expressed by the following approximate formula. That is, ε−ε ₀ = KM, where ε is the dielectric constant of the material at the water content M,
ε ₀ is a dielectric constant specific to the material, and K is a constant determined by the material.

Therefore, the moisture content can be calculated by measuring the change in the dielectric constant of the material at the moisture content M. To do this, it is necessary to calculate the capacitance of the material at the moisture content M under the same measurement conditions. All you have to do is measure it.

Conventionally, in view of the above points, a moisture content measuring device has been proposed that measures the capacitance of a test object using high frequency and measures the moisture 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 a ground electrode 2, and the subject 3 is measured by the high frequency capacitance meter. The signal electrode 1 and the signal electrode 1 are arranged so that the ground electrodes 2 are located on both sides of the signal electrode 1, as shown in FIG. The ground electrode 2 is fixed to the electrode support member 4, the subject 3 is pressed onto the signal electrode 1 and the 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 The capacitance of the subject 3 is measured using the method described above, and the moisture content of the subject 3 is also measured.

The relationship between the thickness of the specimen 3 and the capacitance when measuring the capacitance of paper as the specimen 3 using the moisture content measuring device configured as shown in FIG.
Figure 4 shows the relationship between the thickness of the specimen 3 and the capacitance when the capacitance of paper as the specimen 3 is measured using the moisture content measuring device configured as shown in Figure 2 above. As is clear from FIGS. 3 and 4, if the moisture content measuring device is constructed as shown in FIGS. 1 and 2, the thickness of the specimen 3 There was a drawback that the capacitance of the specimen 3 varied greatly, and therefore the water content of the specimen 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.

As shown in FIG. 5, the water content measuring device of the present invention is arranged such that the signal electrode 11 and the ground electrode 12 are mounted on an electrode support member 13 made of an electrical insulator so that the ground electrodes 12 are located on both sides of the signal electrode 11. The ground electrode 15 facing the signal electrode 11 and the ground electrode 12 of the one electrode 14 is fixed to the electrode support member 16 to form the other electrode 17. Electrode 14
and the other electrode 17 are arranged so that the subject 18 is sandwiched between the signal electrode 11 and the ground electrode 12 of the one electrode 14 and the ground electrode 15 of the other electrode 17, and the signal of the one electrode 14 is A high frequency capacitance meter 20 is connected to the electrode 11 via a shielded wire 19.
The other side of the high frequency capacitance meter 20 is connected to the ground electrode 12 of the one electrode 14 and the ground electrode 15 of the other electrode 17 via the shield wire 21. It is configured to measure the capacitance of the specimen 18 and measure the water content of the specimen 18.

In the above structure, the structure of one electrode 14 and the other electrode 17 is not limited to the above embodiment. For example, one electrode 14 may be arranged around a plurality of signal electrodes 11 as shown in FIG. The signal electrode 11 and the ground electrode 12 are fixed to the electrode supporting member 13 as shown in FIG. The other electrode 17 having a ground electrode 15 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 electrode 12 and the ground electrode 15 of the other electrode 17, or one electrode 1
As shown in FIG. 10, a circular signal electrode 11 is surrounded by a ring-shaped ground electrode 12, the ground electrode 12 is surrounded by a ring-shaped signal electrode 11, and the signal electrode 11 is further surrounded by a ring-shaped ground electrode 12. The above signal electrode 11 and ground electrode 1
2 is fixed to the electrode supporting member 13 as shown in FIG.
The other electrode 17 is configured as shown in FIG. 11, and the one electrode 14 and the other electrode 17 are arranged as shown in FIG. The signal electrode 11 and the ground electrode 12 and the ground electrode 15 of the other electrode 17
The object 18 may be placed between the signal electrodes 14 and the ground electrode 12 surrounding the plurality of signal electrodes 11 as shown in FIG. 11 and a ground electrode 12 are fixed to an electrode support member 13 as shown in FIG. The other electrode 17 having 15 is configured as shown in FIG.
The one electrode 14 and the other electrode 17 are connected to the signal electrode 11 of the one electrode 14 as shown in FIG.
The subject 18 may be placed between the ground electrode 12 and the ground electrode 15 of the other electrode 17, and one electrode 14 may be placed between the first and second electrodes 14.
As shown in FIG. 6, the signal electrodes 11 and the ground electrode 12 are fixed to an electrode support member 13 as shown in FIG. 18 so that the ground electrode 12 surrounds a plurality of signal electrodes 11. One electrode 14 has a ground electrode 15 on its surface facing the signal electrode 11 and the ground electrode 12 provided with an electric insulating spacer Z made of a homogeneous acrylic resin flat plate with a predetermined thickness, as shown in FIG. 17, for example. The electrodes 17 of the electrodes 17 are configured as shown in FIG. The subject 18 may be placed between the ground electrode 15 and the spacer Z.

In addition, in FIGS. 7 to 18 above, the seventh
10, 13, and 16 are plan configuration diagrams of one electrode 14, and FIG. 8, FIG. 11,
14 and 17 are rear configuration diagrams of the other electrode 17, and FIGS. 9, 12, 15, and 18 are diagrams of FIGS. 7, 10, 13, and 16.
The cross section of one electrode 14 taken along the line X-X' and the eighth electrode 14 in the figure.
11, FIG. 14, and FIG. 17, in which one electrode 14 and the other electrode 17 are arranged facing each other in a cross section taken along the line XX' of the other electrode 17.

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 mm), the capacitance is constant.

In this way, when the water content measuring device of the present invention shown in FIG. This means that capacitance 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 moisture content measurement device of the present invention can
This is extremely meaningful because the capacitance of the test object 18 can be measured (within a certain thickness of the test object 18), and the moisture content of the test object 18 can be calculated from the result.

In addition, in the measurement of capacitance in the above example,
A high frequency of 1MHz was used, but the frequency
High frequencies such as 100KHz and 10KHz 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. Moreover, since the signal electrode can be provided on one side, the configuration can be simpler than when the signal electrode is provided on both sides.

[Brief explanation of the drawing]

Figures 1 and 2 are configuration diagrams of the electrodes and specimen of a conventional moisture content measuring device, and Figures 3 and 4 are
2 and 2 are diagrams showing the relationship between capacitance and thickness as measured by the conventional moisture content measuring device, FIG. 5 is a configuration diagram of the electrodes of the moisture content measuring device of the present invention, and FIG. 6 is the present invention. FIGS. 7 to 18 are block diagrams of other embodiments of the electrodes of the moisture content measuring device of the present invention, and FIG. 19 is a diagram of the moisture content measuring device of the present invention shown in FIG. FIG. 20 is a diagram showing the relationship between capacitance and thickness based on the measurement results shown in FIG. 19. In the drawings, 11 is a signal electrode, 12 and 15 are ground electrodes, 14 is one electrode, and 17 is the other electrode.

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.