SU149904A1 - Automatic tracking gauge - Google Patents

Description

The existing devices of high-frequency follow-on level gauges, consisting of a source of frequency-stabilized electromagnetic oscillations, an amplitude modulator, a discriminator with a capacitor sensor, and a common level indicator, do not provide an accurate definition of the interface between the conductive and non-conductive phases.

In the proposed automatic tracking level sensor, parallel to the discriminator with a coaxial capacitive sensor connected to the output of the high-frequency amplifier, a second discriminator with a short-circuited line and a logometer at the output is connected, thereby increasing the accuracy of determining the interface between conductive and non-conducting phases.

FIG. 1 is a block diagram of an automatic follow level gauge; in fig. 2 - schematic diagram.

The block diagram consists of a generator in. /, amplitude modulator 2, a conversion device consisting of discriminator 3 with sensor 4 and discriminator 5 with sensor 6, and pointer 7 (log-oscillator frequency-stabilized oscillators} are fed to discriminator 3, then to amplitude modulator 2 and further. A modulated amplitude with a frequency of 50 Hz is applied to the discriminator 5.

The sensor / is included in the primary circuit 8 of the discriminator 3. and a shorted coaxial line shorter -.,

where is l; - generator wavelength in. h .; eg is the dielectric constant of the non-conductive phase.

The input resistance of such a sensor is an unambiguous function of the short-circuit location of its electrodes, which is effected by an electrically conductive phase and is inductive in nature.

/ one

No. 149904- 2 The primary co-circuit 9 of the discriminator 5 includes a sensor 6 (cylindrical capacitor), the internal electrode of which is covered with an insulating material. In order to increase the accuracy of the immersion level of the interface between the liquid phases, its interelectrode space is partially filled with additional isolation.

Both sensors to the circuits are connected with radio frequency cables 10 and //. To reduce the effect of changing the temperature of the air surrounding the cable, the latter is taken with a copolymer filler. Amplitude detectors 14 and 15, 16 and 17 are connected to circuits 8, 12, 5 and / 5; Amplitude detectors 16 and 17 include a voltage, which is the voltage across the primary winding of the transformer And is equal to the difference in voltage at the output of the detectors 16 and 17, which depends on the difference in the natural frequencies of circuits 9 and 13.

The output of the detectors 14 and 15 is connected to the winding of the logger 7. The own frequency of each circuit is 8, 9, 12 and 13 astraivaagg on the frequency of the oscillations supplied to them. In this case, Bykhh1 1;) ek; .- the detector 16 is equal to the output voltage of the detector 17. Since the voltage on the primary winding of transformer 1 is equal to the difference of the output voltages of the detectors 16 and 17, the output voltage of the transformer 18 is the zero and the trace system keeps the total level on the zero mark. In this case, at the zero point, the arrow is set; and a logometer 7. When the interface between the liquid phases increases and decreases, as well as between the light conductive phase and air, the natural frequencies of the circuits 8 and P differ both from the frequency of the input oscillations and from the natural frequencies of the circuits 12 and 13. In In this case, the output voltage of the detector 14 is not equal to the output voltage of the detector 15, and the output voltage of the detector 1C is not equal to the output voltage of the detector 17. As a result, the output of the transformer 18 produces an electrical signal in the form of a voltage of 50 Hz, f The ase of which depends on the voltage of the level of the interface between the liquid phases. Further, this 1 signal is amplified by cascades of amplifiers 19, 20 and 21 and is applied to the control winding of the reversing motor 22.

As a result, the latter rotates the rotor of the variable capacitor of circuit 13 and the scale until the natural frequency of circuit 13 becomes equal to the natural frequency of circuit 9, and at the output of transformer 18 becomes equal to zero, the rotation with the motor rotor is fixed The arrows make it possible to count only the height of the tank filling -:; -. "; the electroconducting phase. In this case, the ratio of the output voltages of the detectors 14 and 15, which depends on the interface between the le-Koii electrically conductive phase and air, measured with a logometer, makes it possible to determine the location of the interface between the heavy non-conductive and light electrically conductive phases.

The proposed level gauge can measure the interfaces between heavy conductive and light electrically conductive phases, as well as the level of conductive solutions. To do this, it is sufficient to use the discriminator with sensor 6 and the tracking system, and the discriminator with sensor 4 in these cases should be turned off using switch 23.

 In addition, to measure the level of the non-conductive solution, Sensor 6 with additional insulation should be replaced with a sensor without additional insulation.

To reduce the effect of network voltage variation — on the accuracy of measuring the interface between heavy electroconductive and light electroconducting phases, a logometer is used as an indicating instrument.

Subject invention

An automatic tracking level gauge consisting of a source of frequency-controlled electromagnetic oscillations of an amplitude modulator, a discriminator with a capacitor sensor, characterized in that, in order to improve the accuracy of determining the interface between electrically conducting and non-conducting phases, in parallel with the discriminator with a coaxial capacitive sensor connected to the output of the high-frequency amplifier, connected to the second discriminator with a short-circuited line and a logometer at the output.

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