SU968721A1 - Electric moisture-content sensor - Google Patents

Description

(54) ELECTRIC MOISTURE SENSOR

one

The invention relates to a measurement technique, namely, moisture metering, and can be used to measure the dielectric parameters of materials in various sectors of the national economy, for example, in the cotton-ginning industry, when accepting raw cotton at processing centers and at cotton plants.

Known humidity sensor connected to the electronic-measuring unit and containing two cylindrical electrodes, between which is located the test material 1.

However, this sensor is designed to measure the moisture content of the test material, which is sheet, carpet, tape, etc., and cannot be used to determine the moisture content of materials that have a different shape and structure, such as cotton.

The closest technical solution to the invention is an electrical humidity sensor containing a round rod, pointed at one end and connected to an electronic measuring unit on the rod surface a screw groove is cut, filled with a dielectric, a metal tire is applied in the middle of the groove, the beginning and end of which , input and output poles placed on the connectors mounted on the other end of the rod 2.

5 However, multiple use of

The BectHoro sensor under different weather conditions is accompanied by a dielectric falling out of the helical groove and a deflection of the central tire, which leads to a decrease in Q or loss of the sensor performance. In addition, the sensor sensitivity to the main dielectric parameters of the medium is low and does not allow determining the humidity of the studied materials with sufficient accuracy for measurements.

15

Claims (3)

The design features of the known sensor, namely the limited selection of the cross sectional area of the helical groove and the cross sectional area of the metal tire in it, determine its low wave resistance, which gives small increments in the delay time and, accordingly, low sensitivity, making it impossible to measure humidity accuracy sufficient for measurement. The aim of the invention is to increase the sensitivity of the sensor and increase its strength. The goal is achieved by the fact that in an electric humidity sensor containing a round rod, pointed at one end and connected to an electronic measuring unit, the rod is made of three metal tires symmetrically arranged along its length — one middle and two side tires — the gap between which is filled with a magnet soft material, insulated from metal tires by a dielectric layer, with the middle tire at the base of the cone having an opening through which the metal stud passes, connecting the two marketing tires. Along the length of the middle tire, in the corners along its cross section are located the shoulder. The magnetically soft material fills the gap between the tires evenly and is 30-50 ° / vol. The diameter of the stud and the diameter of the hole is chosen from the condition of equality of the wave resistances of the coaxial junction formed by them and the two-wire line formed by one side and middle tires. FIG. 1 shows the proposed sensor section; in fig. 2 is a section A-A in FIG. 1; in fig. 3 is a section BB in FIG. 1. The sensor is made in the form of a rod, pointed at one end (Fig. 1) and contains three metal tires, symmetrically located along the length, side 1 and 2 and average 3 tires. The gap between the tires is filled with a magnet with a soft material 4, for example, ferrite, sectioned along its length. The magnetically soft filler 4 is insulated from the tires (side 1 and 2 and middle 3) with a dielectric layer 5. The middle tire 3 at the base of the cone has a hole b through which the metal stud 7 passes, interconnecting the side tires 1 and 2. In addition, The middle tire has edges 8 located along the length in the corners of the section. Metallic busbars 1-3 have external leads, respectively, 9-11 for connection to an electronic measuring unit (not shown). The sensor works as follows. Before starting the measurement, the sensor is connected via an external terminal 9-11 to an electronic measuring unit (not shown). After that, the sensor is inserted into the material being examined for humidity and is fed to the sensor input (pins 9-11) an electrical impulse that propagates along tire 1, from which an electrical impulse through pin 6 hits the bus 2, which propagates to the sensor output ( conclusions 10-11). From the sensor output, an electrical pulse is applied to the input of the electronic metering unit. , Depending on the moisture content of the material under study (on the dielectric constant), the electrical parameters of the sensor change and, accordingly, the propagation time of the electrical impulse over the metal tires of the sensor increases. This time of propagation of an electrical pulse is recorded by an electronic measuring unit, compared with the reference time determined by the constructive constant of the sensor, and the increment of the propagation time of the electrical pulse for the material under study is measured. The proposed design of the electrical sensor allows one to reduce the running capacity per unit length, while increasing the ratio of the dissipation capacity to the running capacity; sharply increase the ratio of the average permeability to the dielectric constant I in the volume between the metal tires of the sensor. Due to this, the sensor impedance increases by at least 10 times and, accordingly, its sensitivity increases by at least 6-7 times. In addition, the proposed constructive implementation of the sensor (in the form of a rod consisting of three metal tires symmetrically arranged along the length, the gap between which is filled with a magnetically soft material, insulated from the tires with a dielectric layer, and the side tires are interconnected with a metal pin) increases durability sensor and increases its service life. 1. Electric humidity sensor, containing a round rod, pointed at one end and connected to an electronic measuring unit, characterized in that, in order to increase the sensitivity of the sensor and increase its strength, the rod is made of three metal symmetrically arranged along its length tires - one middle and two lateral, the gap between which is filled with a magnet with a soft material, insulated from the tires with a dielectric layer, and the middle tire at the base of the cone has a hole, h Through which there is a metal stud interconnecting the side tires. 2. A sensor according to claim, characterized in that the middle tire has rim located along the length in the corners over the cross section. 3. A sensor according to claim 1, characterized in that the gap between the tires is filled with a magnetically soft material evenly and is 30-50 vol. % 3. The sensor according to claim 1, characterized in that the diameter of the stud and the diameter of the hole