High-frequency moisture meters have been successfully used to measure the moisture content of a number of beneficiation products. However, when measuring the moisture content of bulk materials having low goodness-of-fit (e.g., metal-containing cakes), there are difficulties in developing circuits that allow measurement of the electrical capacitance of the material under low goodness-of-fit conditions ...

The electrophysical characteristics of beneficiation products arriving at mining and processing plants from different deposits tend to be heterogeneous ...

When operating technological systems associated with the use of air or gas flow (for example, systems for purification of industrial gases, pneumostransportation of bulk materials, artificial reduction of air humidity), there is a possibility of getting into the air line drops of liquid ...

Let at a distance d from a plane-parallel layer of thickness a with dielectric constant e a spherical conductor of radius g is placed, or a capacitor consisting of two such conductors located at a distance I from each other ...

The accuracy of measurements of a capacitive moisture-measuring system essentially depends on the extent to which it is possible with its help to measure only the reactive component of the total conductivity of the sample being monitored. An effective method for reducing the error component of the moisture-measuring system (MMS) caused by the influence of active losses and other uncontrolled factors is to measure them and, on the basis of the data obtained, introduce a correction into the output signal of the system.

In the open-pit method of mining, for the transportation of rock mass at open pits of any capacity, road transport has been widely used in recent years, in particular, heavy-duty dump trucks. The BelAZ-540 and BelAZ-548A dump trucks, with carrying capacities of 27 and 40 tons respectively, are operated together with powerful excavators, possess great maneuverability, good operational and speed characteristics, and low requirements for the road profile, and increase the productivity of transport operations in open pits by a factor of 2–3. ...

The traditional approach to the study of sports technique is connected with instrumental methods of recording (kinography, cyclography, stroboscopy) of kinematic characteristics in order to reveal the kinematic structure, i.e. the correlation of movements in time and space. ...

In a discrete moisture-measuring system of the F-meter type, the whole set of measurements of the capacitive component is brought to the calibration temperature in accordance with the temperature coefficient of capacitance of the material being measured...

In resonant methods of moisture measurement, a capacitive sensor with the material under study is in some cases included in the oscillatory circuit of a self-excited oscillator. A change in the moisture content W of the material being monitored leads to a readjustment of the resonant circuit in the anode-grid circuit of the oscillator, which causes a certain increment in the generated frequency. The frequency increment of the self-excited oscillator is converted by frequency discriminators into a direct voltage, which is fed to a measuring instrument. A disadvantage of the considered method of moisture control is the dependence of the operating frequency of the self-excited oscillator on the magnitude of dielectric losses in the material being monitored. At large dielectric losses, the error in moisture measurement can reach significant values. This disadvantage also limits the use of highly sensitive resonant methods.

Changes in the conductivity of a section of an electric circuit are widely used to measure ash content, moisture content, salt content and other parameters of solid, liquid and loose materials; this has made it possible to practically implement a number of measuring instruments and systems that have found wide application in the chemical, mining-metallurgical and other industries, as well as in the power industry and in scientific research. ...

In the development of high-frequency continuous humidity control systems, the most labor-intensive part is developing efficient and operationally reliable sensors. Moisture sensors are usually in contact with bulk material or are in close proximity to it, being exposed to vibrations, temperature effects, abrasion, environmental influences (dampness, dustiness, chemical activity), i.e. interfering factors that distort the information.

Numerous methods of measuring the moisture content of solid, liquid and bulk materials are known: conductometric, based on the use of the relationship between moisture and the active resistance of the material; capacitive – between moisture and dielectric permittivity (more precisely – apparent capacitance); neutron; nuclear magnetic resonance – NMR, etc.

The principle of autocompensation makes it possible to increase the accuracy of moisture control systems, which can be shown by an analysis of such systems from the position of information theory. The average value of negentropy – the amount of information required to obtain the limiting accuracy of the measured quantity q0, calculated from the sensor current, is about 7 decimal units. However, the sensor current contains not only useful information about the controlled moisture, but also interference (noise). ...

The electrophysical properties of materials are influenced by many factors: moisture content, temperature, grain-size and chemical compositions, etc. Therefore, the total differential, for example, of the volumetric resistance of saltpeter can be represented as an equation. Similar equations can be written for capacitance and dielectric loss factor.. ...

The efficiency of processing of numerous types of mining-chemical and mining-metallurgical raw materials (coal, apatite, nepheline, phosphorite, sulfur, copper, iron, nickel ores, etc.) is significantly reduced in the absence of reliable and valid information on moisture content. Obtaining such information is associated with known difficulties, and to date the domestic industry has not carried out serial production of moisture-metric systems. Consider the possibility of building a moisture-metric system on the principle of phase separation of controlled and uncontrolled parameters.

Creation of the system for express discrete determinations of phosphate flour moisture content within 0-3,5% was preceded by the study of its electrophysical properties. For this purpose, the dependence lg r = F1 (W) ( r and W - respectively the volume resistivity and moisture content of phosphate flour) was obtained at direct current.

The rational method of measuring the moisture content of certain materials, the optimal operating frequency at which these measurements will be carried out, and hence the rational scheme of the measuring device can be outlined only by analyzing the frequency characteristics: ρ (ω) - resistivity; ε (ω) - dielectric permittivity; tgδ (ω) - loss angle of the controlled material. The applied methods of obtaining families of frequency characteristics at different moisture contents by broadband bridges with separate readout of active resistance r and apparent capacitance C (for example, bridge of the E-10-2 type) are time-consuming and, as a rule, lead to significant errors associated with changes in the parameters of the wet material during the study. It is necessary, therefore, to reduce the time required to obtain the frequency characteristics so that the temporal instability of the material parameters can be neglected. It should also be borne in mind that the methods used involve a large number of individual measurements (several tens and even hundreds).