SU1663403A1 - Device for measuring mass irregularity of extensive objects - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure the transverse dimensions of long objects, for example threadlike materials, in the textile industry. The aim of the invention is to improve the measurement accuracy. The device contains a measuring bridge circuit with a capacitive transducer, in the three arms of which resistors are included, and in the fourth - a high-frequency generator with a variable resistor and a shunt capacitor. The capacitive transducer contains one low-potential and three high-potential electrodes - the main and two additional. Additional electrodes are installed on both sides of the main one and are powered synchronously and in phase with the generator. The low-potential and main high-potential electrodes form a capacitor included in the oscillating circuit of the high-frequency generator, which determines the frequency of its oscillations. The device eliminates the edge effect at the ends of the plates of the capacitive transducer and eliminates the influence of high frequency currents on the measuring circuit. 1 il.

Description

The invention relates to an instrumentation technique using capacitive methods for controlling the transverse dimensions of extended objects and can be used, for example, to control the linear density of yarn in the textile industry.

The purpose of the invention is to improve the measurement accuracy.

The drawing shows the electrical circuit of the proposed device,

The device consists of a low-potential electrode 1, a high-potential electrode 2, a high-frequency generator 3 with a variable resistor 4, shunted by a capacitor 5, two high voltage potential electrodes 6, installed in the same plane as the high-potential electrode 2 on both sides of it and through a capacitor 7 connected with an amplifier 8, which is connected via capacitor 9 with a generator 3, a shielding housing 10, an indicator 11c with a resistor 12 to adjust its sensitivity and resistors 13, 14 and 15. Between the electrode 1 and electrodes 2 and b form a vertical slit for pulling the controlled filament material 16.

The device works as follows.

When power is applied, generator 3 operates in a self-oscillating mode, and the frequency of self-oscillations is determined by OI ON SA

yo

with

The capacitance of the capacitor of the oscillating circuit, the plates of which are electrodes 1 and 2. The self-oscillation frequency also determines the value of the internal resistance of the generator 3, which, together with resistors 13, 14, 15, implements the measuring bridge.

In this mode, indicator 11 first balances the bridge circuit (zero setting) with resistor 4, then, using a control sample of a filamentous material inserted between electrodes 1 and electrodes 2 and 6, the indicator 11 is calibrated with resistor 12, the control sample is entered between electrodes 1 and 2 leads to a change in the dielectric constant of the capacitor of the oscillating circuit of the generator 3, therefore, the frequency of self-oscillations and, accordingly, the internal resistance of the generator. Thus, an imbalance of the bridge circuit occurs that is proportional to the mass of the introduced control sample.

After the calibration of the indicator 11, instead of the control sample, filament material 16 is inserted and pulled between the electrodes. The capacitance change of the capacitor of the oscillating circuit formed by electrodes 1 and 2 is proportional to the change in the mass of filament material 16 between electrodes 1 and 2, which leads to imbalance bridge circuit and fixed indicators 11.

Improving the measurement accuracy is achieved by linearizing the measurement field (eliminating the edge effect) at the ends of electrode 2 by creating electric fields with additional electrodes 6 fed synchronously and in phase with a capacitor and amplifier 8, the input of which is connected to generator 3 through a capacitor 9 to eliminate work measuring bridge.

In addition, an increase in the measurement accuracy is achieved both by reducing the magnitude of the parasitic capacitances, since the flow of the high-frequency signal from generator 3 is localized only through one. the shoulder of the measuring bridge, which is located in the screen housing (10) and shunted by the capacitor 5, and due to the construction of the measuring capacitor

(electrodes 1 and 2) in the form of an open slot, significantly reducing the degree of dustiness.

Claims (1)

Invention Formula A device for measuring unevenness in the mass of extended objects, containing a measuring bridge, a high-frequency generator included in it, a capacitive transducer with one low-potential and main and additional high-potential electrodes, and an indicator, which is equipped with a second additional high potential electrode, three resistors connected to the three arms of the bridge, the first and second variable resistors, the first capacitor connected in series by the second capacitor, an amplifier and the third capacitor, additional high-potential electrodes are installed in the same plane with the main one on either side of it and connected to the third capacitor, the fourth shoulder of the bridge has a series-connected high-frequency generator and the first variable resistor and the first capacitor parallel to them, the high-frequency generator is designed as an auto-generator, whose oscillator circuit includes a capacitor formed by low-potential and main high-potential electrodes, and a second variable ezistor included in the measuring diagonal of the bridge consistent with the indicator.  +