JPH0617868B2 - Infrared moisture analyzer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an infrared moisture measuring device for continuously measuring moisture of an object to be measured such as cloth or paper that is dried by a dryer such as a cylinder dryer. .

<Prior Art> When a material to be dried such as cloth is dried by a dryer such as a cylinder dryer, the amount of water is constantly measured and the amount of heat supplied to the dryer in order to uniformly and uniformly dry the material. Need to be adjusted. Therefore, conventionally, for example, an infrared moisture meter is brought close to a continuously measured object to measure the moisture content.

The infrared moisture meter utilizes that water has a large absorption at a specific wavelength of infrared rays. That is, there is a large absorption band for water near the wavelength of near infrared rays of 1.94 μm. Using a calibration curve showing the relationship between the absorbance and the moisture value, the moisture value conversion value is obtained from the absorbance in this wavelength band.

<Problems to be Solved by the Invention> In the above measuring method, there is an adverse effect due to environmental humidity. That is, since the infrared moisture meter cannot be brought into contact with the object to be measured, it must be installed with a certain gap between it and the object to be measured. Therefore, since the infrared light emitted from the moisture meter is absorbed by the object to be measured, and at the same time, it is also absorbed by the humidity of the atmosphere up to the object to be measured, the true amount of water of only the object to be measured cannot be obtained. . In particular, since the vicinity of the surface of the object to be measured immediately after drying is filled with steam, the influence of the humidity is great.

Therefore, the technical problem of the present invention is to make it possible to continuously measure the water content of an object to be measured without being affected by environmental humidity.

<Means for Solving the Problems> The above-mentioned problems are, in an infrared type measuring device for measuring the water content of an object to be measured, such as a cloth, which is continuously dried by a cylinder dryer, in which the object to be measured is in contact with the peripheral side surface and continuously. A rotating cylindrical roller, a two-wire optical fiber arranged so as to open the peripheral side surface and the side wall surface of the roller and connect both opening windows, and the roller is opened on the side wall surface of the roller by rotating. A two-wire optical fiber arranged such that the end faces of the window and the side wall of the roller are alternately faced, a device for supplying infrared rays for measurement to one line of the two-wire optical fiber, and another one of the two-wire optical fiber. A light receiving device that receives reflected light from the object to be measured and the side wall surface of the roller via an electric wire to generate an electric signal, and an arithmetic device that continuously receives the electric signal from the light receiving device to calculate the water content of the object to be measured. And It can be solved by the technical means of the present invention.

It should be noted that the number of windows opened on the peripheral side surface and side wall surface of the roller is not limited to one set, but may be appropriately arranged on the peripheral side surface of the roller as necessary, and a window corresponding to each window may be formed on the side wall surface of the roller. It is also possible to connect each with a wire optical fiber.

<Operation> Infrared rays with a wavelength absorbed by water are radiated to the side wall surface of the rotating roller through one line of a two-line optical fiber. The radiated infrared rays are absorbed by the moisture existing in the air and hit the side wall surface to be reflected, enter the light receiving device through the other one line of the two-line optical fiber, and are converted into an electric signal. The value obtained at this time indicates the environmental humidity.

On the other hand, since the roller is rotating, when the end surface of the optical fiber matches the window formed on the side wall surface of the roller, the infrared rays are formed on the peripheral side surface of the roller via the two-wire optical fiber arranged inside the roller. The window is reached and the object to be measured is illuminated. Part of the irradiated infrared light is reflected while being absorbed by the object to be measured, and again the other one of the two-wire optical fiber is reflected.
The light enters the light receiving device through a wire and is converted into an electric signal. The value obtained at this time is a combination of the water content and the environmental humidity of the measured object.

Based on the electric signal obtained above, the difference between the value returned by irradiation of the object to be measured by the arithmetic unit and the value returned by irradiation on the roller side wall surface is calculated, and the water content converted value is calculated from the degree of absorption. Is calculated.

<Example> An example showing a specific example of the above technical means will be described. (No.
1 to FIG. 3) The cylindrical roller 2 rotates about a shaft 4, and an object to be measured 8 such as cloth abuts against the peripheral side surface 6 of the roller 2 and flows. Measuring window 6 on the peripheral side 6
A coupling window (10a) is opened in the side wall surface (10) of the roller (2) and the roller (2), and the two are connected by a two-wire optical fiber (12). In addition, in this embodiment, measurement windows 6b and 6c (6c is not shown) are opened on the peripheral side surface 6 and coupling windows 10b and 10c are also opened on the side wall surface 10 in order to measure the water content at three points. Then, they are connected by two-wire optical fibers 14 and 16, respectively. The coupling windows 10a, 10b, 10c are arranged at equal intervals (120 degrees) on the same circumference with the axis 4 as the center.

On the other hand, the coupling window 10a, b, c in which the end face 20 rotates the coupler 22 in which the end face 20 of the two-wire optical fiber 18 is opened.
Are arranged so as to face each other and are fixedly arranged independently of the roller 2. Further, a proximity switch 24 is built in the coupler 22, and a pin 26 for the proximity switch is attached immediately below the coupling window 10a.

Reference numeral 28 is a measuring instrument side, which is connected to the two-wire optical fiber 18 and has an infrared light emitting lamp 30 inside thereof, an optical filter 32 for selecting a specific wavelength, and a condenser lens for converging light rays.
34, a light receiver 36 for converting the light reflected from the object to be measured into an electric signal, an amplifier 38, lock-in amplifiers 40a, b, c,
Delay circuit 42,44, AC / DC conversion circuit 46a, b, c, A / D converter 48,
It is composed of the arithmetic unit 50, and the measurement procedure will be described below.

The infrared light of a specific wavelength absorbed by water is guided to the end face 20 of the coupler 22 through the object to be measured of the two-wire optical fiber 18 and is irradiated. Since the roller 2 is rotating, if the end surface 20 of the roller 2 faces the coupling window 10a (state of FIG. 1), the light emitted from the end surface 20 is measured through the object to be measured of the two-wire optical fiber 12. It reaches the window 6a and is irradiated to the DUT 8. The light applied to the DUT 8 is absorbed by the DUT and passes through the other one line of the two-wire optical fiber 12 and the coupler 22.
It reaches the light receiver 36 via and is converted into a corresponding electric signal. The value obtained at this time corresponds to the sum of the water content of the DUT 8 and the water content in the atmosphere between the end face 20 of the coupler 22 and the coupling window 10a.

On the other hand, since the roller 2 is rotating, the light emitted from the end surface 20 is absorbed by the water present in the atmosphere and the side wall surface.
Upon being reflected by 10 and reflected through the other one line of the two-line optical fiber 18, it enters the light receiver 36 and is converted into a corresponding electric signal. The value obtained at this time corresponds to the amount of water in the atmosphere between the end surface 20 of the coupler 22 and the side wall surface 10.

Further, the roller 2 rotates, and the above measurement is performed every time the end face 20 of the coupler 22 faces the coupling windows 10b and 10c. number 3
The figure shows the passage of time and the signal value of the reflected light obtained by the light receiver 36.Level A is the signal level returned by the side wall surface 10 and returned, and B is reflected by the DUT. The signal level returned from the measurement windows 6a, 6b, and 6c and the signal returned from the side wall surface 10 and returned are sequentially repeated.

The electric signals thus obtained are amplified and input to the lock-in amplifiers 40a, 40b, 40c, respectively. This received light signal is output by the lock-in amplifier 40a only at the same frequency as the signal obtained by the proximity switch 24 and in phase synchronization. That is, only the signal in the coupling window 10a provided with the proximity switch 24, that is, the measurement window 6a can be obtained. The signals obtained from the measurement windows 6b, c are detected and output by the lock-in amplifiers 40b, c whose phase is shifted by the delay circuits 42,44, respectively.

The signals output by the lock-in amplifiers 40a, 40b, 40c are converted into digital signals by the A / D converter 48 via the AC / DC conversion circuits 46a, 46b, 46c, respectively, and are shown in FIG. So level A
And the level B are calculated, the water content of only the DUT 8 is calculated.

<Effect of the Invention> According to the present invention, the difference between the reflected light of the irradiated infrared light from the measured object and the reflected light from the side wall surface of the roller is calculated, so that the measured object is not affected by environmental humidity at all. Only the amount of water can be measured.

In addition, in the case of a normal infrared moisture meter, in order to eliminate changes over time of equipment such as light sources and light receiving elements, a chopping mechanism that emits infrared rays of another wavelength as a reference in addition to the infrared rays for measurement However, in the case of the present invention, the side wall surface of the roller functions as the rotating plate even without using the chopping mechanism.

[Brief description of drawings]

FIG. 1 is an explanatory view of an infrared type moisture measuring device in an embodiment of the present invention, FIG. 2 is an end view of the AA line in FIG. 1, and FIG. 3 is obtained with the passage of time and the light receiver 36. It is the figure which displayed the relationship of the signal value of the reflected light. 2: Roller, 6a, b, c: Measurement window 10: Roller side wall surface, 10a, b, c: Coupling window 12,14,16,18: 2-wire optical fiber 22: Coupler, 24: Proximity switch 28: Measuring instrument

Claims (1)

[Claims] 1. An infrared type measuring apparatus for measuring the water content of an object to be measured, such as a cloth, which is continuously dried by a cylinder dryer, and a cylindrical roller which is in contact with the object to be measured and continuously rotates. A two-wire optical fiber arranged so as to open the peripheral side surface and side wall surface of the roller and connect both opening windows, and the window opened on the side wall surface of the roller and the side wall surface of the roller when the roller rotates. A two-wire optical fiber arranged so that the end faces thereof alternately face each other, a device for supplying infrared rays for measurement to one line of the two-wire optical fiber, and an object to be measured through another one line of the two-wire optical fiber. Infrared moisture measuring device including a light receiving device that receives reflected light from the side wall surface of the roller to generate an electric signal, and an arithmetic device that continuously calculates the water content of an object to be measured by receiving the electric signal from the light receiving device. .