SU1408336A1 - Apparatus for measuring moisture content of loose materials - Google Patents

Abstract

The invention relates to a measurement technique and can be used to control the moisture of existing materials, such as grains. The purpose of the invention is to improve the accuracy and simplify the device. The device contains a source of alternating voltage, an adjustable resistor # a bunker with an outflow regulator, a capacitor formed by two electrodes and a container placed between them, into which the material flows out of the bunker. The purpose of the invention is achieved by using as a scoring criterion the mass of the expired material, which can be measured with high accuracy. 2 nl.

Description

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The invention relates to a measuring technique, namely to measuring the humidity of bulk materials and can be used in agriculture for pre-sowing and post-harvest processing of the grain mass.

The goal of the inventor is to improve accuracy and simplify the measurement of humidity,

Fig, 1 schematically shows the proposed device; in fig. 2 - curves explaining the operation of the device.

The device contains a source of alternating current electrical energy ;, a resistor with adjustable resistance 2j regulate flow, a capacitor with inclined electrodes 3 and 4, which are installed under the hopper 5 and form the capacitance Cj,, the measuring capacitor with flat vertical electrodes 6 and 7 which form the capacitance j tare 8 of electrically insulating material installed in the interelectrode space of the measuring capacitor.

Curve 9 (FIG. 2) shows the dependence of voltage 11, on regulating ™

cement capacitor C, moisture content of the material for stop flow regime (lock), curve 10 - the dependence of the same voltage on the capacitance Cj of the measuring capacitor,

curves 11 and 12 - capacitance dependence

I

mass of bulk material, gd in packaging; for humidity W ,, and W, and | W W ,, curve 13 - dependence; mass of HPP material in packaging, on humidity W after the termination of the outflow of material from the regulating capacitor C.J4.

The device works as follows

Source 1 sets the voltage and 5 whose value ensures the outflow of the material of the highest humidity from the regulating capacitor in the absence of a mother in the container 8 and the outflow of the material of the lowest humidity in the capacitor C, 4 when the container 8 is filled (the largest and smallest values of humidity are specifications for the material or for the technological process of its processing and are assumed to be known). The value of the voltage installed at the source 1 and during the measurement process is maintained unchanged.

P1 CONTRIBUTED bulk material is fed to the hopper 5 (FIG. 2), from where it flows gravitationally through regulating capacitor C. and enters the container 8. As the material accumulates in the latter, the capacitance of the measuring capacitor C increases and the voltage drop across the series circuit elements is redistributed and namely, the voltage drop on Cj increases, while on Cg7 it decreases, since the output of source 1 maintains a constant voltage value and, while the capacitance C3 remains almost unchanged. An increase in the voltage drop across a regulating capacitor leads to a decrease in the rate of flow of material in it. Thus, a negative feedback takes place between the amount of material in the measuring capacitor and the flow rate in the regulating capacitor. After accumulating in the container 8 some specific amount of material, the voltage on the regulating capacitor I reaches the value that blocks the flow of material in it. For this voltage source 1, the amount of material in the container 8 is uniquely determined by its humidity, and its humidity is determined by the weight of the accumulated material.

Uniqueness of the dependence m (W). The illustrated curves in FIG. 2. At humidity W, the outflow blocking in the regulating capacitor corresponds to point A (curve 9). To provide this mode, the capacitance of the measuring capacitor must correspond to point A. (curve 10). At humidity W, the capacitance of the measuring capacitor corresponds to point A.-, if the amount of material in container 8 is determined by point A (curve 11), which occurs when the amount of material in container B is unambiguously dependent on its moisture content (point A on curve 13). At humidity W, the unique dependence ma (W) is determined by point B (curve 13). Moreover, with an increase in humidity W, the amount of material accumulated in container 8 by the time of locking expiration decreases. This decrease is a result of two reasons: at higher humidity, for locking outflow in the regulating capacitor, a smaller value of the voltage drop U is needed; at higher humidity, for the same amount of material, the capacitance of the measuring capacitor is larger. For each type of material, an individual graduation of the scale of dependence t (W) is carried out.

Claims (1)

Invention Formula A device for measuring the moisture content of bulk materials, containing a source of 15 voltage source, and the other - with a resistor, a bunker with a material outflow regulator, the voltage source being connected to the outflow regulator through an adjustable resistor, characterized in that, in order to improve the accuracy and simplify the device, it additionally contains vertical electrodes forming the measuring capacitor, a container of electrically insulating material the container is placed inside the vertical electrodes and is installed under the bunker, one electrode is connected to source of voltage and the other with a resistor, a bunker with a material outflow regulator, the voltage source being connected to the outflow regulator through an adjustable resistor, characterized in that, in order to improve the accuracy and simplify the device, it additionally contains vertical electrodes forming the measuring capacitor, a container of electrically insulating material the container is placed inside the vertical electrodes and is installed under the bunker, one electrode is connected to variable voltage adjustable bunker flow controller. / l2  Rig.2