JPS58118950A - Method for measuring moisture of raw material of iron manufacturing - Google Patents

Abstract

PURPOSE:To make possible measurement of the moisture content and temperature in the object to be measured without contact in a state of open-air storage, by utilizing the fact that an equivalent dielectric constant is varied by the moisture content and emissivity of a raw material powdered and granular body is varied accompanied by the variation of the equivalent dielectric constant and measuring thermal radiation at >=0.4mum wavelength. CONSTITUTION:A circular horn antenna 2 receiving thermal radiation from an object to be measured 1 is arranged at an observation angle theta1 for the object 1 and heat radiation electric power received by the antenna 2 is amplified and detected by a ferrite rotor 3, a receiver 4 and a synchronous detector 5. And, switching of a vertical polarized wave and horizontal polarized wave is carried out by the rotor 3 and the detector 5 in a constant frequency by a synchronous oscillator 6 and the difference of both waves is detected and then, the moisture content is measured by its detected value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the moisture content of raw materials for iron making such as coal, sinter, quicklime, etc.

Conventional methods for measuring moisture retention in powdered materials such as raw materials for steelmaking (coal, sinter, quicklime, etc.) include: ■ Neutron moisture needle method (using elastic scattering of neutron beams); ■ Water pressure in the infrared region. A method that uses resonance absorption, ■Medielectricity by inserting a probe into the raw material 4! -Direct measurement method; ■Measurement method that utilizes absorption and attenuation by moisture through transmission and reflection of microwaves.

However, the neutral hand moisture needle method (■) has the disadvantage that its handling is restricted due to safety management, and the method (■) that uses resonance absorption by water in the infrared region measures moisture in the surface layer, so it cannot be used in yards. It has the disadvantage that it cannot be applied to thick materials such as raw materials, and the dielectric constant direct measurement method described in (■) has the disadvantage that it is a local measurement and is not suitable for wide-area measurements.
The method of measuring ψ using microwaves has the disadvantage of being limited by the shape of the object to be measured (constant pigeon thickness) and the positional relationship with the measuring device.

As described above, with conventional methods, it is not possible to measure a wide range of moisture, especially when measuring moisture in open yard conditions.
There are problems such as not being able to measure the internal conditions, and difficulty in measuring if the shape of the IJJJ material powder changes.

This invention was made to solve the above-mentioned conventional problems, and it is possible to measure a wide range of raw materials piled up in a yard without contact, including the internal condition, and even when the shape of the object to be measured changes. The purpose of this study is to propose a method that can be used to measure not only moisture but also temperature.

In other words, Jin's invention focused on the fact that the equivalent dielectric constant changes with changes in the water content in the raw material powder, and that the emissivity of the raw material powder changes as the equivalent permittivity changes. This is a method to measure the moisture content and temperature in the powder by measuring thermal radiation (brightness temperature) at a wavelength of 0.4 or more. This method is characterized by alternately measuring both waves and horizontally polarized waves, and detecting the temperature and moisture content of the powder and granular material.

This invention method will be explained in detail below.

Figure 1 is an explanatory diagram of the principle of the method for measuring thermal radiation (brightness temperature) of a measurement target. (1) is the measurement target, (2) is a circular horn antenna, etc. An antenna that receives radiation and is installed at an observation angle of - with respect to the object to be measured (1) K.

That is, in the method of this invention, changes in emissivity are detected from K by measuring thermal radiation (brightness temperature) at waves *Q, 4- or higher. The brightness temperature (T1) is the physical temperature (T) of the object to be measured.
and emissivity (ε), T) CCT”
(1) becomes.

In addition, the emissivity (ε) is the equivalent dielectric constant (
gt) and the observation angle #O function, which is expressed as 1 k/Cat, #) (1).

In addition, the equivalent permittivity (at) is the permittivity of the powder (#厖),
It is a function of the dielectric constant of water (#W) and water content (W),
g @ oc y (1m, aw, W) (
1).

From the above formulas (1) and (1), Ding Bcch (T, gy, gy, W, #) (■) is obtained.

Here, the permittivity of powder (#, , ), the permittivity of water (8w
) is known, the brightness temperature (T1) is the measurement target (1)
It is determined by the temperature (T), moisture content (W), and observation angle (θ).

Next, when parallel polarization is used, as shown in Figure 2, in a certain observation angle range 11, K
However, the emissivity (It) for parallel polarized waves is almost 1, and it is possible to capture only changes in the temperature (T) of the object.

In addition, when using vertical polarization, the emissivity (ε
As shown in Figure 3, ρ is the moisture content (
W). Therefore, by measuring the brightness temperature (TTI) in vertically polarized waves and parallel polarized waves, 11 ・ 12 7 ccr@a□ (V) 1↓ 7, cc7・machi, (■) 1 The difference can be used to measure the emissivity, or moisture content, of the object, removing the effects of temperature changes on the object.

Note that the above formula (1) T1Q:T11ε is Ra+ylt
Ray 1 @i gh-J @ams law =,
, &T (,: radiance, λ: wavelength, k: Holtzmann's constant) is within 1 OwI & difference, and the condition is approximately λ≧O
In this invention, we decided to measure the thermal radiation (brightness temperature) at a wavelength of O# or more.

Next, an example of a rounding device for carrying out the method of this invention will be explained based on FIG.

(2) is a circular horn antenna that receives thermal radiation from the measurement object (1) as described above, and is installed at an observation angle (#, ) with respect to the measurement object (1). (3) is Ferri 41
Rotor, (4) receiver, (5) synchronous detector, (6)
indicates a synchronous oscillator, that is, the thermal radiation power received by the antenna (2) is distributed between the AFI 1 rotor (S), the receiver (
4) and a synchronous detector (5) for amplification tube detection. And synchronous oscillation i! (6), the ferrite rotor (
3) and a synchronous detector (5) switch between vertical polarization and horizontal polarization at a constant frequency, detect the difference between the two, and measure the moisture content from the detected value.

Since the receiver (4) has a very small reception power of about 10-10 W, a high-sensitivity receiver generally called a voltage meter is used.

Here, an example in which the above-mentioned apparatus is used to target coal will be described.

The dielectric constant of powdered coal is gm: u, gm = 0.1 (gms = go) at a frequency of 10 GHz (wavelength of 30 GHz).
/−jε2), and the equivalent permittivity when containing water is #
The relationship between t and water content is as shown in FIG. In addition, the relationship between brightness temperature TB and moisture W in the case of vertical polarization when the observation angle is θ-60'' is as shown in Figure 6, and is determined by measurement with a receiver with brightness temperature resolution ΔTN of IK. 0.2LII
Moisture can be measured with a certain degree of accuracy. In addition, the temperature of coal can be measured from the brightness temperature IQ: TBI□ in the case of parallel polarization.

As explained above, according to the method of this invention, it is possible to simultaneously measure the moisture content and temperature of raw materials without contact, and by using a long wavelength band, especially for raw materials piled up in yards, it is possible to measure the moisture content and temperature of raw materials, including internal conditions. Measurement is also possible. Furthermore, by scanning the thermal radiation receiving antenna, measurements over a wide range can be easily performed, which can greatly contribute to the proper management of moisture and temperature of raw materials.

[Brief explanation of the drawing]

′! Figure A1 is a detailed explanatory diagram of this invention, @Figure 2 and Figure 3
The figure is a chart showing the relationship between observation angle and emissivity in this invention method, Figure 4 is a block diagram showing an example of a device for implementing this invention method, and Figure 5 is a diagram showing the relationship between the observation angle and emissivity in the same example. Dielectric constant r! Figure 6 is a diagram showing the relationship between moisture value and brightness temperature in the same example. 1...Measurement pair 11 objects, 2...Antenna, 3...7
Equipment rotor, 4... Receiver, 5... Synchronous transverse wave device, 6... Synchronous oscillation 4° Applicant: Sumitomo Metal Industries, Ltd. Figure 1 Figure 2 Viewpoint angle θ Figure 3 Parent Angle of deflection θ 3% 5 Figure 6 Moisture W (%)

Claims (1)

[Claims] 1. Change in emissivity due to change in dielectric constant of the object to be measured,
A method for measuring moisture in steelmaking and dr IIA materials, characterized by detecting by measuring thermal radiation with a wavelength of 0.4 cm or more, and measuring the moisture content and temperature in the object to be measured from the detected value. . 2 The change in emissivity due to the change in dielectric constant of the object to be measured is expressed as
Alternately measuring parallel polarized waves and vertically polarized waves with a wavelength of 0.4111 or more. Detecting from K and measuring the moisture content and temperature in the object to be measured using both values and their axes. A method for measuring the moisture content of raw materials for steelmaking, which is characterized by: