Thickness detection device and method based on semi-cylindrical shell capacitor

A technology of thickness detection and capacitor, which is applied in the direction of electromagnetic measuring device, electric/magnetic thickness measurement, etc., can solve the problems of shortening machine life, increasing industrial cost, secondary dust rapping, etc., and achieves low cost, convenient operation and effective detection Effect

Active Publication Date: 2020-05-01

JIANGSU UNIV

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AI-Extracted Technical Summary

Problems solved by technology

Since the fixed rapping frequency cannot adapt to various conditions, it often causes secondary dus...

Abstract

The invention provides a thickness detection device and method based on a semi-cylindrical shell capacitor. The thickness detection device comprises the semi-cylindrical shell capacitor, a base, a sensor and a controller, wherein the semi-cylindrical shell capacitor comprises an outer polar plate and an inner polar plate; the outer polar plate and the inner polar plate both comprise an upper compensation polar plate, a middle working polar plate and a lower compensation polar plate in sequence from top to bottom; the base comprises an outer ring and an inner ring that are nested, the upper part of the inner ring is connected to the lower compensation polar plate of the inner polar plate, the inner ring is connected to a driving device, and the upper part of the outer ring is connected to the lower compensation polar plate of the outer polar plate; and the controller is connected to the upper compensation polar plate, the middle working polar plate, the lower compensation polar plate, the sensor and the driving device, respectively. The invention can adapt to the variable environment of an industrial chimney, can accurately, quickly and effectively detect the thickness of dust deposition by adopting a double-compensation processing method of the upper and lower polar plates, and is suitable for the detection of the thickness of particles and liquid.

Application Domain

Electrical/magnetic thickness measurements

Technology Topic

PhysicsElectrical and Electronics engineering +4

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Examples

Experimental program(3)

Example Embodiment

[0069] Example 1

[0070] like Figure 4 As shown, when the object to be detected is dust, the detection method based on the thickness detection device of the semi-cylindrical shell capacitor includes the following steps:

[0071] When not detected, the outer pole plate 7 and the inner pole plate 9 are attached and merged together;

[0072] When wanting to detect the thickness of dust deposition, the stepping motor works to drive the inner pole plate 9 to rotate at a certain angle, so that the outer pole plate 7 and the inner pole plate 9 are opposite;

[0073] The dielectric constant of the dust-air mixture and the dielectric constant of the deposited dust at the current temperature are obtained through the upper compensating electrode plate 1 and the lower compensating electrode plate 4, as the dielectric constant reference of the middle working electrode plate 3 for measuring the dust thickness. The medium of the upper compensating electrode plate 1 is all air-dust mixture, because the distance between the plates, the relative area and the capacitance are known, the dielectric constant of the air-dust mixture at the current temperature can be measured. Similarly, the medium of the lower compensation plate 4 is all dust deposits, and the dielectric constant of the dust deposits at the current temperature can also be measured.

[0074] Dust is deposited to different thicknesses on the middle working electrode plate 3, which will generate different capacitances, and the current dust thickness can be obtained by detecting the capacitance. Therefore, the capacitance of the middle working electrode plate 3 can be calculated by knowing the dielectric constants of the two states, so that the height of the dust deposits on the middle working electrode plate 3 can be calculated, combined with the height of the device and the lower compensation electrode. The height of the plate 4, the dust thickness can be calculated.

[0075] After the detection is completed, the inner pole plate 9 rotates back and is attached to the outer pole plate 7 .

[0076] The present invention is based on the detection method of the dust thickness of the semi-cylindrical shell capacitor, and the thickness calculation features are:

[0077] Capacitance C under the current environmental conditions measured by the upper compensation plate 1 上 , through the differential amplifier circuit, converted into a measurable voltage signal U 上 , the voltage signal can be calculated by the microcomputer to obtain the capacitance C 上 , θ o is the notch angle formed by the inner and outer plates 9 and 7, l 气-尘 Compensate the height of plate 1 for the upper part. When the length of the semi-cylindrical shell capacitor is much larger than the radius, these known values can be calculated according to formula 8 to obtain the dielectric constant of the air-dust mixture under the current environmental conditions as ε 气-尘.

[0078]

[0079] In the same way, from the detection result of the lower compensation plate 4, the dielectric constant of the dust deposition thickness under the current environmental conditions can be calculated according to formula 9 as ε 沉积. where C 下 is the capacitance measured by the lower plate in the current environment, θo is the angle formed by the inner and outer plates 9 and 7, l 沉积 Compensate the height of the plate 2 for the lower part.

[0080]

[0081] The air-dust mixture and the dust deposition height can be calculated according to Equation 10.

[0082]

[0083] can be calculated as:

[0084]

[0085] Substitute Equation 8 and Equation 9 into Equation 11 to get:

[0086]

[0087] where, l 沉积2 is the height of dust deposits on the middle working plate 3, l 气-尘2 is the height of the air-dust mixture in the middle working plate 3, l 中部极板 is the total length of the middle working plate 3, C 中 , C 上 , C 下 is the measured value, l 气-尘 is the height of the upper compensation plate 1, l 沉积 Compensate the height of the plate 2 for the lower part.

[0088] Height H at which the binding device is installed 装 , so as to obtain the current dust deposition thickness H 灰 , its calculation formula is:

[0089] H 灰 =H 装 +l 沉积2 +l 沉积 Formula Thirteen

[0090] Convert Equation Thirteen to:

[0091] That is, the dust thickness H 灰 for:

[0092] In the thickness detection device based on the semi-cylindrical shell capacitor according to the present invention, the self-cleaning method in the detection process is as follows: before the detection, the inner wall of the inner pole plate 9 is always attached to the ash blocking rod 8, and the outer diameter of the inner pole plate 9 is always equal to the inner diameter of the outer pole plate 7; when preparing to detect, when the inner pole plate 9 is unscrewed, the dust on its inner wall is cleaned by the dust blocking rod 8, the inner wall of the outer pole plate 7 is cleaned by the inner pole plate 9, and the two electrode walls are Clean; after the detection, the inner pole plate 9 rotates back, the inner wall of the inner pole plate 9 is cleared of adhering dust by the dust blocking rod 8, and the inner pole plate 9 rotates relative to the outer pole plate 7, the inner surface of the outer pole plate 7 and the inner pole The dust on the outer surface of the board 9 is cleaned off at the same time, and the surface of the device is initialized, waiting for the next inspection. In this way, the dust thickness inside the industrial chimney can be measured simply, conveniently and quickly.

[0093] in formula ten θ o is the angle formed by the inner and outer pole plates 9 and 7, C 中 is the measured value, l 中部极板 is the fixed height of the middle working plate 3, ε 气-尘 with ε 沉积 is an unknown variable, l 气-尘2 with l 沉积 2 is to be measured. ε 气-尘 with ε 沉积 The change of will affect the final required l 气-尘2 with l 沉积2 , so it is necessary to obtain the dynamically changing ε in real time 气-尘 with ε 沉积. However, using the upper and lower compensation plates, since the upper, middle and lower plates are almost in the same environment, it can be calculated by the formula A very accurate ε is obtained according to the dynamically changing capacitance C 气-尘 with ε 沉积 dynamically change the value to obtain an accurate l 气-尘2 with l 沉积2.

[0094] If no compensation plate is used, ε 气-尘 with ε 沉积 It can only be preset by the system based on experience, but the environment where the middle working plate 3 is located changes drastically, and the actual ε 气-尘 with ε 沉积 is unstable, the resulting l 气-尘2 with l 沉积2 is also inaccurate.

Example Embodiment

[0095] Example 2

[0096] The object to be tested in this example 2 is particulate matter. The difference between this example 2 and example 1 is that the thickness detection formula of the particulate matter is:

[0097]

[0098] H 颗粒物 =H 装 +l 颗粒物2 +l 颗粒物 formula sixteen

[0099] In the formula, l 颗粒物2 and l 气2 is the value to be measured, l 颗粒物2 is the height of particles in the middle plate, l 气2 is the air height in the middle plate, C 总 , C 上 , C 下 is the measured value, l 气 For the height of the upper compensation plate 1, the upper compensation electrode, 1 is completely filled with the gas inside the device, l 颗粒物 For the height of the lower compensation plate 4, the lower compensation plate is completely filled with particles.

Example Embodiment

[0100] Example 3

[0101] The object to be tested in this embodiment 2 is a liquid. The difference between this embodiment 3 and Embodiments 1 and 2 is that the thickness detection formula of the liquid is:

[0102]

[0103] H 液体 =H 装 +l 液体2 +l 液体 formula eighteen

[0104] where l 液体2 and c is the value to be measured, l 液体2 is the liquid height in the middle plate, l 液体2 is the air height in the middle plate, C 总 , C 上 , C 下 is the measured value, l 气 For the height of the upper compensation plate 1, the upper compensation electrode, 1 is completely filled with the gas inside the device, l 液体 For the height of the lower compensation plate 4, the lower compensation plate is completely filled with liquid.

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Classification and recommendation of technical efficacy words

Simple structure
effective detection

Thickness detection device and method based on semi-cylindrical shell capacitor

AI-Extracted Technical Summary

Problems solved by technology

Abstract

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Examples

Example Embodiment

Example Embodiment

Example Embodiment

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Description & Claims & Application Information

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