SU920495A1 - Device for measuring loose material humidity - Google Patents

Description

(5) DEVICE FOR MEASURING HUMIDITY OF BULK

MATERIALS °

I

The invention relates to the field of materials control by physical methods and can be used in the coal and mining industries for continuous moisture control.

A device is known for measuring the moisture content of bulk materials in a stream, based on measuring the power loss of electromagnetic energy in a wet sample. This device contains an inductive sensor, powered by an RF oscillator, and located near the test material SP.-i,

The drawback of the device is the low accuracy of the moisture measurement due to the low sensitivity and sensitivity of the analysis, which is explained by the concentration of the electromagnetic field inside the coil and the weak penetration into the material. Immersion of the sensor in the test material reduces reliability

device and makes it necessary to struggle with sticking. .

The closest technical solution to the present invention is a device, which is an RF auto-oscillator, in the circuit of which a sensor is inserted through which the material under study passes. 121 The disadvantages of this device are that it does not allow material of variable mass, t. e. bulk materials with varying filling height. To compensate for the height of the layer of material, additional

15 devices, which complicates the design.

The purpose of the invention is to increase the sensitivity of measurements.

The goal is achieved by the fact that in the device for measuring

Claims (2)

30 humidity, made in the form of a generator, in the circuit of which a sensor is inserted, the sensor is made in the form of an inductance coil, half of the turns of which is located in a plane perpendicular to the plane in which the second half is located on the turns. The drawing shows the device. The device contains a conveyor belt 1, on which the source material 2 is located, the sensor 3, which is part of the oscillating circuit of the RF generator, is connected via an emitter follower to an FM detector 5 installed under the conveyor belt 2. Outputs of if-density meter 6 and FM detector 5 are connected to the input of a computing device 7 connected to an indicator device 8. The device operates as follows. The test material 2, located on the conveyor belt 1, passes between the turns of the induction sensor 3, which is part of the oscillating circuit of the RF generator k. The material moisture is judged by the frequency of the generator, which decreases with increasing humidity, density and height of the filling material. This is explained by the change in the parameters of the coil, namely, its active resistance due to the increased loss of RF power to conduction currents. A change in the frequency of the RF generator is recorded by an FM detector 5. A y-density meter 6 is applied to compensate for the effects of density fluctuations. results Measurements by measuring time using a timer device and also provides for correction of instrument readings depending on the type of material, which is carried out using a block of coefficients. The signals from the output of the computing device 7 are fed to the indicator device $, graduated in: 3 values of humidity. The advantage of the proposed device is to improve the measurement accuracy by eliminating the influence of the height of the layer of material under investigation, which is achieved by arranging the turns of the sensor coil so that the upper layer of the material is outside the sensitivity range of the sensor and the sensitivity to humidity is maximum. On the basis of the experiments performed, the optimal angle between the sensor coil, which is equal to 90 °, was chosen. The choice of sensor dimensions is determined by the geometrical dimensions of the conveyor belt and the height of the layer of material in this process stream. The absence of additional devices to control the height of the layer and to prevent adhesion simplifies the device. The device can be widely used in coal preparation plants for controlling the moisture content of coal. The invention The device for measuring the moisture content of bulk materials, containing a measuring generator, in the circuit of which the sensor is inserted, distinguishing it with the aim of raising -. Neither the sensitivity of the measurements, the sensor is made in the form of an inductance coil, half of the turns of which is located in a plane, perpendicular to the plane in which the other half of the turns are located. Sources of information taken into account during the examination 1.Arsh E.I. High-frequency oscillator control in mining. M., Nedra, 1971, p. 21. 2. Zarynsky.V.A., Ermakov V.I. High-frequency chemical analysis. M., Science, 1970, p. 15 (prototype).