SU1040341A1 - Electroconductive media level checking device - Google Patents

Abstract

A METHOD FOR MONITORING THE LEVEL OF ELECTRICAL CONDUCTING MEDIUM, in which a waveguide, shorted at one end, is immersed in a controlled medium, electromagnetic waves of the main type are excited in it, characterized in that, in order to improve measurement accuracy, electromagnetic oscillations are excited in more than two resonant frequencies, and the level inversely proportional to the time interval between the two extremes of any three consecutive resonant pulses determines the level of electrically conductive media. (L with: oo

Description

The invention relates to a measurement technique and can be used to control the level of electrically conductive media in various capacitances, in particular, to measure the level of liquid metal in the rotary crystallizers of a casting-irokatny aggregate of ferrous and ferrous metals, where it is possible to use the transmission and reception of electromagnetic waves as a waveguide groove of a rotary crystallizer. For measuring the level of electrically conductive media, microwave (microwave) level gauges are used, which use the principle of sounding the microwave signal. the surface of the controlled medium through the gas phase above the medium, and at the same time the level of the medium is judged by the value of the time interval between the moment the probe signal is sent and the time when radio signals are reflected from the surface, or by the amplitude (phase) of the standing wave generated in the space between the antenna and the radiator surface of the controlled medium 1. The disadvantages of such level gauges are low accuracy, design complexity and dependence of the result on the initial position of the level, i.e. scarlet process measurement output signal value corresponding to the present position of the level in the tank. The closest to the proposed method is a method according to which the number of half-waves of the interference pattern formed in a waveguide receiving-transmitting line (link), immersed in a controlled medium perpendicular to its surface, is determined. A disadvantage of the known method is the low accuracy of measurement . The purpose of the invention is to increase measurement accuracy while simplifying hardware implementation. The goal is achieved by the method of controlling the level of electrically conductive media, in which a waveguide shorted from one end is immersed in a controlled medium, excites electromagnetic oscillations at more than two resonant frequencies, and is proportional to the time interval between two extreme three consecutive resonant pulses are judged on the level of electrically conductive media. FIG. 1 shows a block diagram of the device; in fig. 2 - time diagram of his work; in fig. 3 - the proposed sensor mounted on a rotor mold; in fig. 4 — experimental curve (solid line) of the dependence of the cavity length on the time interval between two extreme of any three consecutive resonant pulses. The characteristic is taken off at the waveguide cross section ahz 10x23 mm, frequency change ± 9, 8 MHz from the carrier, generator GLPD-2. An example implementation of the method is a device for controlling the level of electrically conductive media consisting of a sensor and a secondary converter. The sensor contains (Fig. 1) a guide coupler 1, to which the microwave generator 2 of varying frequency is connected, a detector head with a detector of a 3 line of communication in the form of a rectangular waveguide 4. The secondary converter contains a generator 5 of linearly varying voltage (CLAY), the device 6 for launching the CLAY and setting zero triggers, the driver 7 pulses, the trigger 8 and 9, the integrator 10 and the indicator 11. The device works as follows. Modulated by the sawtooth voltage, the microwave oscillations from the generator 2 through the directional coupler 1 and the link 4, immersed in the controlled medium, are radiated in its direction. The waveguide resonator is formed by a short-circuiting detector head, the main branch of the directional coupler, and the surface of the controlled medium. The detector 3 produces resonant pulses that are applied to the counting input of the first trigger 8, operating from the leading edge of the pulse in the frequency division mode. The output of the trigger 8 is connected to the input of the second trigger 9. Both triggers are set to the zero state when GLIN 5 is started. The resonant impulse fp-j sets the triggers 8 and 9 to one state (Fig. 2). The impulse fp causes the trigger 8 to the zero state. The impulse brings the trigger 8 into one, and the trigger 9 into the zero state. The time it takes for trigger 9 to be in unit state is tp.-tp. and inversely proportional to the length of the resonator, which determines the level of the medium.

tp 1tptpi-1

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tpi-r- ip-f

FIG. 2

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mm

8.5

Theoretical 3 / (crrepuMeHma i} Haff

 p +} tp-f, ms

needles

Claims (1)

METHOD FOR CONTROL OF THE LEVEL OF ELECTRIC CONDUCTING MEDIA, in which a shorted waveguide is immersed into the controlled medium from one end of the wave and excites electromagnetic waves of the main type in it, characterized in that, in order to increase the measurement accuracy, they excite electromagnetic waves at more than two resonant frequencies, and the value inversely proportional to the time interval between two extreme of any three consecutive resonant pulses, judge the level of conductive media.