JPS5844977B2 - Suibunsokuteihouhou Oyobi Sonosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in a moisture measuring method and a moisture measuring device using microwave power.

As a method for quickly measuring the moisture content of wood, paper, soil, chemicals, etc. using the bone-dry method, there is a moisture measuring device that combines a weighing scale and a microwave heating device.

For example, as shown in Fig. 1, this device has a heating furnace 2 consisting of a metal box with a door 1 on the front, and a magnetron 3 as a microwave oscillation source and a radio stirring blade 4 for uniform heating installed on the earthen wall of the heating furnace 2. A partition plate 5 and a mounting plate 7 for storing the object to be measured 6 are removably provided inside the heating furnace 2, and a support body that contacts the mounting plate 7 in series and holds the mounting plate 7 is provided. 8 passes through a hole 9 in the lower wall of the heating furnace 20 and is connected to a weighing scale 10 disposed at the bottom of the heating furnace 2 .

Conventionally, in such moisture measuring devices that irradiate microwave power onto the object to be measured to make it completely dry, the mounting plate that houses the object to be measured is made of a material with low microwave absorption, such as hard glass, Teflon, ceramic, etc. was used because of its excellent heat resistance.

Incidentally, the object to be measured generally has a property that microwave absorption decreases when the moisture content is low.

Therefore, when the object to be measured approaches an absolutely dry state after being irradiated with microwave power, the microwave absorption decreases, and the mounting plate
Both of the objects to be measured have the disadvantage that due to the effect of cooling, it is not possible to obtain a sufficient temperature rise for moisture evaporation, and it takes a long time to reach an absolutely dry state.

The present invention was made in view of the above circumstances, and the temperature of the mounting plate itself is raised to a temperature of 80°C or higher and 180°C or lower, so that even if the object to be measured approaches an absolutely dry state, moisture will be absorbed by the high-temperature mounting plate. The object of the present invention is to provide a moisture measuring method and a moisture measuring device that can obtain a sufficient temperature rise for evaporation and shorten the measurement time, and one embodiment thereof will be described below.

In the moisture measuring device with the configuration shown in Figure 1, a hard glass with clay sand, which has good microwave absorption, mixed as an impurity is used as a mounting plate to obtain a temperature rise sufficient for moisture evaporation. Measurements were made.

Figures 2 and 3 show the relationship between heating time and weight change when using a conventional Teflon mounting plate and the mounting plate of the present invention, respectively.
As shown in the figure.

Oscillation source frequency 2450MH2, output 600W
A magnetron was used.

Figure 2 shows the change in soil weight.

Broken line A indicates the case of a conventional mounting plate, and as the object to be measured approaches absolute dryness, the lapse rate drying curve becomes gentle, and a measurement time of approximately 30 minutes is required.

Solid line B shows the case of the present invention, which uses a mounting plate designed to provide a sufficient temperature rise for water evaporation, and the measurement time can be reduced to 10 minutes or less.

In addition, since the upper limit of temperature increase in soil can be varied up to about 180°C, a material with a temperature range of 150°C to 180°C was used for the mounting plate.

In this case, if the temperature of the mounting plate exceeds about 180° C., crystal water and the like will evaporate and the composition will change, making it impossible to obtain an accurate moisture content.

Figure 3 shows the change in paper weight.

Broken line A indicates the case of a conventional mounting plate, and as the object to be measured approaches absolute dryness, the effect of cooling increases, and an absolute dry state cannot be obtained even after 30 minutes have elapsed.

Solid line B is for a mounting plate made of a material that has a temperature of 80° C. to 100° C., which has the effect of keeping the object to be measured warm and the effect of raising the temperature, so it can maintain a temperature sufficient for moisture evaporation.

Therefore, an absolutely dry state can be obtained in about 15 minutes.

In the case of a conventional mounting plate, the temperature of the mounting plate when approaching absolute dryness was 50°C to 70°C.

As mentioned above, if the temperature of the mounting plate is set to between about 80°C and 180°C and the microwave power is irradiated to the object to be measured, even if the object to be measured approaches an absolutely dry state and the microwave absorption decreases. The heat of the mounting plate allows the object to be measured to be maintained at a temperature sufficient for moisture evaporation, making it possible to efficiently measure moisture in a short time.

It is recognized that the effect decreases as the temperature of the mounting plate becomes lower than 80°C.

Furthermore, in the above embodiment, the mounting plate was formed of a material containing a substance that absorbs microwaves well, and the temperature of the mounting plate itself rose when irradiated with microwave power. The temperature of the mounting plate is not limited to increasing the temperature of the plate, and other heat sources such as infrared rays, nichrome heaters, etc. may be used to raise the temperature of the plate.

As described above, in the present invention, the temperature of the mounting plate for storing the object to be measured is set to approximately 80° C. or more and 180° C. or less, and the object to be measured is irradiated with microwave power to be in an absolutely dry state.
Moisture can be measured from the initial weight and bone-dry weight, and the measurement time can be significantly shortened compared to conventional methods, as well as using materials containing substances that have good microwave absorption when irradiated with microwave power. A moisture measuring device is provided that includes a formed mounting plate, a microwave oscillation source, a heating furnace, and a weighing scale connected to the mounting plate.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view showing the schematic structure of the moisture measuring device;
The figure is a characteristic diagram of one embodiment showing heating time and weight change to explain the present invention, and FIG. 3 is a characteristic diagram of another embodiment showing heating time and weight change to further explain the present invention. be. 1... Door, 2... Heating furnace, 3... Magnetron,
6...Object to be measured, 7...Place plate, 10...Weighing meter.

Claims (1)

[Claims] 1. A moisture measuring method in which an object to be measured is placed on a mounting plate, irradiated with microwave power to make it completely dry, and the moisture content is measured from the initial weight and absolute dry weight of the object to be measured, Approximately 80 mounting plates
A moisture measurement method in which the object to be measured is heated to a temperature of 180°C or higher and irradiated with microwave power. 2. In a moisture measuring device equipped with a heating furnace connected to a microwave oscillation source and a weighing scale connected to a mounting plate for the object to be measured, the mounting plate is formed of a material containing a substance that absorbs microwaves. A moisture measuring device characterized by: