RU2624657C1 - Cake thickness sensor - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: cake thickness sensor comprises electrodes made in the form of two flat combs having teeth and a base in form of plane rectangles interconnected and located on a flat insulating sensor base, the teeth of the first comb enter into the gaps between the teeth of the second comb to form a uniformly alternation of teeth and gaps therebetween, the width of the gap between teeth is equal to the tooth width, immersed in a vessel with a liquid, forming a cake, the electrodes included in the capacitance measuring circuit between the electrodes, where additional electrodes are installed on the two diametrically opposite corners of the sensor so that at least three flat L-shaped electrodes are located on each mentioned corner, wherein the inner L-shaped electrode is formed by a tooth and a base of relative flat comb.

EFFECT: providing the possibility of improving the measurement accuracy.

3 cl, 4 dwg

Description

The invention relates to measuring technique and can be used to create sensors for monitoring the thickness of sediment in sediment-forming liquids.

A known sediment thickness sensor containing electrodes immersed in a vessel with liquid, included in the capacitance measurement circuit between these electrodes, wherein the electrodes are made in the form of flat combs deposited on a flat dielectric base mounted on the bottom of the vessel (A.S. USSR No. 309229 , application No. 1409792 / 25-28 of 11/27/1970, IPC: G01b 7/34 - prototype).

The sensor operates as follows. The precipitate, in the form of a thin layer covering the base of the sensor, leads to a change in capacitance between the electrodes deposited on this base. The balance of the capacitance measuring circuit is violated, and an electric signal appears at its output, corresponding to the controlled thickness of the sediment.

The main disadvantage of the sensor is the insufficiently high measurement accuracy associated with the presence of an edge effect when the sensor capacitance changes.

The objective of the invention is to provide a sensor for monitoring the thickness of the sediment with a reduced effect of the capacity of other bodies on the change in the capacity of the working fluid of the condenser, which will allow to level the edge effect and thereby increase the accuracy of measurements.

The solution to this problem is achieved by the fact that, in the proposed sensor control the thickness of the sediment containing electrodes made in the form of two flat combs having teeth and a base in the form of flat rectangles connected to each other and applied to a flat dielectric base of the sensor, while the teeth of one comb enter into the gaps between the teeth of the second comb with the formation of uniformly alternating teeth and gaps between them, and the width of the gap between the teeth is equal to the width of the tooth, immersed in a vessel with liquid forming sediment, and included in the capacitance measurement circuit between these electrodes, according to the invention, additional electrodes are installed from two diametrically located sensor angles in such a way that at least two flat L-shaped electrodes are located at each said angle, with an internal L-shaped the electrode is formed by a tooth and the base of the corresponding flat comb.

In an embodiment, the gaps between the additional electrodes are equal to the gaps between the teeth of the comb.

In an embodiment, the gaps between the additional electrodes and the additional electrodes and teeth of the comb are equal to the gaps between the teeth of the comb.

The essence of the technical solution is illustrated by drawings, where in FIG. 1 shows a general view of the proposed sensor, FIG. 2 - sensor in a tank with sediment-forming liquid, in FIG. 3 - distribution of field lines in the presence of an edge effect without additional electrodes, in FIG. 4 - distribution of field lines without edge effect with additional electrodes.

The sludge thickness control sensor contains electrodes made in the form of two flat combs 1 and 2, having teeth 3 and 4, respectively, and a base in the form of flat rectangles 5 and 6, interconnected and deposited on a flat dielectric base 7 of the sensor. The teeth 3 of one comb enter the gaps between the teeth 4 of the second comb with the formation of uniformly alternating teeth and gaps 8 between them. The width of the gap 8 between the teeth is equal to the width of the tooth 3 or 4. With two diametrically located corners of the sensor, additional electrodes 9 and 10 are installed in such a way that at least two flat L-shaped electrodes are located on each said corner, while the internal Г- the shaped electrode is formed by a tooth and the base of the corresponding flat comb.

The sensor is immersed in a vessel 11 with a liquid forming a precipitate, and is included in the circuit for measuring the capacitance between the electrodes (not indicated and not shown).

The proposed sensor is used as follows.

The sensor is immersed in a vessel 11 with a liquid forming a precipitate, and is included in the circuit for measuring the capacitance between the electrodes. Sediment 12 precipitates from the sedimenting liquid and covers the flat dielectric base 7 of the sensor.

Sediment 12, in the form of a thin layer covering the flat dielectric base 7 of the sensor, leads to a change in capacitance between the electrodes made in the form of two flat combs 1 and 2 having teeth 3 and 4, respectively, and the base in the form of flat rectangles 5 and 6 connected to each other and applied to a flat dielectric base 7 of the sensor, while the presence of additional electrodes 9 and 10 eliminates the edge effect.

The balance of the capacitance measuring circuit is violated, and an electric signal appears at its output, corresponding to the controlled thickness of the sediment.

Using the proposed technical solution will allow you to create a sensor to control the thickness of the sediment, eliminating the edge effect, and thereby improve the accuracy of measurements.

Claims (3)

1. A sensor for monitoring the thickness of the sediment, containing electrodes made in the form of two flat combs having teeth and a base in the form of flat rectangles interconnected and deposited on a flat dielectric base of the sensor, while the teeth of one comb enter the gaps between the teeth of the second comb with the formation of uniformly alternating teeth and gaps between them, and the width of the gap between the teeth is equal to the width of the tooth, immersed in a vessel with the liquid that forms the sediment, and included in the measurement circuit of the capacitance between these electrodes, characterized in that from two diametrically located corners of the sensor additional electrodes are installed in such a way that at least two flat L-shaped electrodes are located on each said corner, while the internal L-shaped electrode is formed by a tooth and the base of the corresponding flat comb. 2. The control sensor according to claim 1, characterized in that the gaps between the additional electrodes are equal to the gaps between the teeth of the comb. 3. The control sensor according to claim 1, characterized in that the gaps between the additional electrodes and the additional electrodes and teeth of the comb are equal to the gaps between the teeth of the comb.

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