KR102391635B1 - Precise Measurement Device of the Dielectric Constants of Liquid Dielectrics - Google Patents

Abstract

The present invention provides a precise measurement device of the dielectric constant of liquid dielectric, wherein an error in measurement is minimized using the principle of cross capacitance. The present invention provides a precise measurement device of the cylindrical dielectric constant of liquid dielectric, comprising: four main electrodes symmetric in four directions, arranged with minute gaps therebetween and having a cross section in the shape of an arc; cylindrical guard electrodes arranged with minute gaps from upper ends and lower ends of the four main electrodes to have ground voltage and having the inner diameter identical to the inner diameter of the four main electrodes; a cylindrical insulator for electrically insulating the outer circumference surfaces and the bottom surfaces of the four main electrodes and the guard electrodes by enveloping the same while maintaining gaps between the four main electrodes and gaps between the four main electrodes and the guard electrodes to be uniform; and a cylindrical case for shielding static electricity by enveloping the outer circumference surface and the bottom surface of the insulator and formed to be able to contain liquid to be measured.

Description

Precise Measurement Device of the Dielectric Constants of Liquid Dielectrics

The present invention relates to an apparatus for accurately measuring the most important dielectric constant among dielectric properties of various liquid dielectrics using the cross capacitance principle, and more particularly, to a cylindrical liquid dielectric that minimizes measurement errors with high accuracy It relates to a precision measuring device for dielectric constant.

The standard method for measuring the dielectric constant of a liquid recommended by the international standard IEC 60249 is a two-terminal electrode structure, after injecting the liquid to be measured between two metal cylinders, the measured capacitance, and the measurement target It is determined by calculating the ratio of the measured capacitance in air after the liquid has been removed.

However, since the electrode is made of a metal material and the insulator is made of molten glass, etc., the electrode structure must be disassembled, cleaned, and reassembled every time before and after injecting the measurement target liquid into the measurement cell (device).

In addition, it is almost impossible to obtain the same capacitance because the position between the opposing electrodes is changed every time the electrode structure is reassembled.

Therefore, it is necessary to calibrate the characteristics of the measuring cell itself every time it is measured. That is, it is necessary to calibrate the characteristics of the dielectric constant measuring device by using a liquid whose dielectric constant is already known in the measuring device.

On the other hand, when the dielectric is a liquid that is easily evaporated, such as benzene, when it evaporates from the surface, the temperature of the surface becomes lower than that of the lower part by the heat of vaporization, so there is a problem inevitably causing a measurement error of capacitance due to temperature imbalance.

In addition, the measurement cell for measuring the dielectric constant must be manufactured according to the state of the liquid to be measured, and one of the counter electrodes must be surrounded by a guard electrode in order to remove the edge effect of the electrode. .

Therefore, in the two-terminal electrode structure, the measurement error is about 0.5 to 1% due to the instability of the electric field distribution due to the influence of various external noises and the stray capacitance during the capacitance measurement process.

In order to supplement this, the 3-terminal electrode structure developed by the present inventor is disclosed in Patent Document 1.

That is, in the three-terminal electrode structure, a guard electrode having an appropriate spacing and size is added around one of the counter electrodes.

However, when measuring a 3-terminal electrode structure, there are still problems due to the cleaning and reassembly of the device and the temperature effect.

In order to solve this problem, a cell for measuring dielectric constant to which the cross-capacitance principle previously developed by the present inventor is applied is disclosed in Patent Document 2.

In this case, the outer surface of a test tube made of an insulator such as quartz or ceramic is plated with gold, the plating surface is partially removed, and the four opposed electrodes arranged in the axial direction of the test tube and the opposite electrodes are placed above and below the test tube. It is composed of a guard electrode having a ground potential.

That is, in Patent Document 2, since all electrodes are adhered to the outer wall of an insulator such as quartz, the cumbersome process of disassembly, washing, drying, and reassembly is unnecessary, unlike the existing ones, and it is possible to measure with only a small amount of liquid, and chemical It can solve the problem of chemical reaction between chemicals and metal electrodes.

In addition, due to the structural nature of measuring capacitance with the liquid to be measured filled inside the test tube, not only the properties of the liquid but also the properties of insulators such as quartz are measured in a mixed state. Liquids can be measured accurately in a short time.

However, when the gold-coated electrode is formed on the outer wall of the quartz test tube, as shown in FIG. 1 (1), if the dielectric constant of the liquid to be measured is 3.78 or less, which is lower than the dielectric constant of the quartz itself, the measurement error will be 0.5% or less, but the liquid to be measured As the dielectric constant of , the measurement error increases rapidly.

For example, in the case of a liquid having a dielectric constant of 50, the measurement error is almost 48%.

Among the methods for solving this problem, when an electrode is formed inside an insulator test tube such as quartz as shown in FIG. 1 ( 2 ), the error becomes almost zero.

However, it is extremely difficult to coat the entire inner circumferential surface (inner curved surface) of a test tube that is closed on one side, and even if gold is coated on the inner circumferential surface of the test tube, a small line is removed from the gold surface to form 4 main electrodes and 2 guard electrodes. There is a big technical problem to form, and it is very difficult to draw the electrical wiring out of the test tube.

The background or prior art described herein is information possessed by the inventor or acquired in the process of deriving the present invention, and is only intended to help in understanding the technical meaning of the present invention, and prior to the filing of the present invention, the technology to which this invention belongs This does not mean that the technology is widely known in the field.

Republic of Korea Patent Publication No. 10-1991-0005057 Publication Date 1991.03.29 Republic of Korea Patent Registration No. 10-0299310 Registration Date 2001.06.07

Therefore, the present inventor comprehensively considers the above-mentioned issues and at the same time, based on the electrostatic theory of Thompson-Lampard, from the idea of solving the technical limitations and problems of the existing IEC method, the three-terminal electrode method, and the quartz test tube method By applying the cross-capacitance principle, we put great effort into developing a precision measuring device for cylindrical dielectric constant of liquid dielectric that can achieve the effect of minimizing all kinds of liquid dielectric constant measurement error to a level of 0.05% or less. As a result of continuous research, the present invention was created.

Accordingly, it is an object and technical problem to be solved by the present invention to provide a cylindrical dielectric constant precision measuring device of a liquid dielectric to minimize the measurement error.

Here, the technical problems and objects to be solved by the present invention are not limited to the technical problems and objects mentioned above, and other technical problems and objects not mentioned will be clearly understood by those skilled in the art from the following description.

Specific means according to an aspect of the present invention for effectively achieving a specific technical purpose while embodying a new idea for solving the technical problem of the present invention as described above is, while forming symmetry in all directions, a minute gap (gap), the four main electrodes formed in an arc-shaped cross section, each of which is arranged to have a ground potential with a minute gap at the upper and lower ends of the four main electrodes, and the inner diameter of the four main electrodes is the same A cylindrical guard electrode having an inner diameter, a gap between the four main electrodes and an outer circumferential surface (outer curved surface) of the four main electrodes and the guard electrodes while uniformly maintaining the gap between the four main electrodes and the guard electrode and a cylindrical insulator that surrounds and electrically insulates the bottom surface, and a cylindrical case formed to surround the outer peripheral surface (outer curved surface) and bottom surface of the insulator to shield static electricity and contain the liquid to be measured. A precision measuring device for cylindrical dielectric constant of liquid dielectric is presented.

Accordingly, the present invention can minimize the degree of measurement error when measuring the dielectric constant of the liquid dielectric.

)를 산출하는 것을 특징으로 하는 액체 유전체의 유전상수 정밀 측정장치를 제시한다.As a preferred embodiment of the present invention, cross capacitance between the main electrodes E1 and E3 is measured in a state where a liquid dielectric sample is placed in the case, and after measuring the cross capacitance between the main electrodes E2 and E4, the liquid Remove the dielectric sample, measure the cross capacitance between the main electrodes E1 and E3 in air, and substitute the measured cross capacitance between the main electrodes E2 and E4 into Equation 4 to obtain the dielectric constant (

) presents a precision measuring device for dielectric constant of a liquid dielectric, characterized in that it is calculated.

According to the technical idea and embodiment of the present invention, which is based on a unique solution to solve the above technical problem, an excellent effect of minimizing the measurement error to about 0.01 to 0.03% in the range of the dielectric constant 4.0 to 81.0 there is.

Here, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a graph showing a measurement error analysis result according to the shape of a cylindrical electrode of a dielectric constant measuring device for a liquid.
2 is a perspective view showing a main electrode and a guard electrode in the precision measuring device for the cylindrical dielectric constant of a liquid dielectric according to an embodiment of the present invention.
3 is a perspective view showing a cylindrical dielectric constant precision measuring device of a liquid dielectric according to an embodiment of the present invention.
4 is a longitudinal cross-sectional view showing a cylindrical dielectric constant precision measuring apparatus of a liquid dielectric according to an embodiment of the present invention.
5 is an enlarged cross-sectional view showing a cylindrical dielectric constant precision measuring apparatus of a liquid dielectric according to an embodiment of the present invention.
6 is a graph showing the measurement error analysis results according to the thickness change of the main electrode and the guard electrode of the precision measuring device for the cylindrical dielectric constant of the liquid dielectric according to the embodiment of the present invention.
7 is an enlarged cross-sectional view schematically showing a cylindrical dielectric constant precision measuring apparatus of a liquid dielectric according to another embodiment of the present invention.
8 is an exploded perspective view of a cylindrical dielectric constant precision measuring apparatus of a liquid dielectric according to another embodiment of the present invention.
9 is a longitudinal cross-sectional view showing a cylindrical dielectric constant precision measuring device of a liquid dielectric according to another embodiment of the present invention.

Hereinafter, an embodiment according to the present invention will be described in more detail with reference to the accompanying drawings.

Prior to this, the terms described below are defined in consideration of the functions in the present invention, which indicate that they should be interpreted as concepts consistent with the technical spirit of the present invention and meanings commonly or commonly recognized in the art.

In addition, when it is determined that a detailed description of a known function or configuration related to the present invention may obscure the gist of the present invention, the detailed description thereof will be omitted.

The accompanying drawings show that parts are exaggerated or simplified for explanation of the configuration and operation of the technology and for convenience and clarity of understanding, and it is revealed that each component does not exactly match the actual size and shape.

In addition, in this specification, the term and/or is meant to include a combination of a plurality of related described items or any of a plurality of related described items, and when a part includes a certain component, it is a description that is specifically opposite This does not mean that other components are excluded, but other components can be further included.

That is, terms such as 'include' or 'comprising', 'having' and the like mean that the features, numbers, steps, operations, components, parts, or combinations thereof described and illustrated in the present specification exist, It is to be understood that this does not exclude the possibility of addition or existence of one or more other features or numbers, step operation components, parts, or combinations thereof.

And terms such as upper, lower, upper, lower, upper, lower, upper, lower, front and rear, left and right are used for convenience to distinguish relative positions of each component. For example, the upper side in the drawing may be named or referred to as the upper side and the lower side as the lower side, the longitudinal direction may be named or referred to as the front-back direction, and the width direction may be named or referred to as the left/right direction.

Also, terms such as first, second, etc. may be used to describe various components. That is, terms such as 1st, 2nd, etc. may be used only for the purpose of distinguishing one component from another component. For example, a first component may be referred to as a second component without departing from the protection scope of the present invention, and the second component may also be referred to as a first component.

As shown in Figures 2 to 5, the cylindrical dielectric constant precision measuring device of the liquid dielectric according to an embodiment of the present invention is largely composed of four main electrodes (E1, E2, E3, E4), guard electrodes (G1, G2), It includes an insulator (I) and a case (C).

The four main electrodes E1, E2, E3, and E4 are symmetrical in all directions around an imaginary axis and are insulated with a small gap between them, and their cross-sections are arc-shaped, respectively. is formed

In addition, the four main electrodes E1, E2, E3, and E4 are formed in a shape having a constant length L vertically.

That is, the four main electrodes E1, E2, E3, and E4 have a cylindrical electrode structure.

The guard electrodes G1 and G2 are respectively arranged to have a ground potential with a minute gap at the top and bottom ends of the four main electrodes E1, E2, E3, and E4.

That is, the guard electrodes G1 and G2 consist of two, one of which is positioned with a small gap between the upper ends of the main electrodes E1, E2, E3, and E4, and the other is the main electrodes E1, E2, E3, E4) It is positioned with a small gap from the lower end.

In addition, the guard electrodes G1 and G2 have the same inner diameter as the ground potential and the inner diameters of the four main electrodes E1, E2, E3, and E4, that is, have a hollow cylindrical shape.

The insulator I includes a gap between the four main electrodes E1, E2, E3, and E4 and a gap between the upper and lower ends of the four main electrodes E1, E2, E3, E4 and the guard electrodes G1 and G2. It is formed in a cylindrical shape to surround and electrically insulate the outer peripheral surface (outer curved surface) and the bottom surface of the four main electrodes (E1, E2, E3, E4) and the guard electrodes (G1, G2) while maintaining the there is.

That is, the insulator I is formed by a gap between the four main electrodes E1, E2, E3, and E4, and the upper and lower ends of the four main electrodes E1, E2, E3, E4, and upper and lower guard electrodes ( The four main electrodes (E1, E2, E3, E4) and the upper and lower guard electrodes (G1, G2) are electrically insulated from each other while maintaining the gap between G1 and G2 uniformly at 0.1 to 0.2 mm. It is provided between the outer circumference and the inner circumference of the case (C).

The case (C) is formed in a cylindrical shape to surround the outer peripheral surface (outer curved surface) and the bottom surface of the insulator (I) to shield static electricity and contain the measurement target liquid.

That is, the case C is made of a metal container that can contain the liquid to be measured, and serves as an electrostatic shielding role to block noise from the outside.

Here, since the case C is made of a metal material, the effect of the insulator is completely excluded, so that the error can be almost zero.

Meanwhile, in order to assemble and fix the four main electrodes E1, E2, E3, E4 and the two guard electrodes G1, G2 in a perfectly symmetrical state, the four main electrodes E1, E2, E3, E4 ), a cylindrical jig having the same outer diameter as the inner diameter can be used.

That is, after attaching four main electrodes E1, E2, E3, E4 and two guard electrodes G1, G2 to the outer circumferential surface (outer curved surface) of the cylindrical jig at predetermined positions, an insulator I is formed It can be fixed by applying and hardening the epoxy thickly.

At this time, the epoxy is applied to the gap between the four main electrodes E1, E2, E3, and E4, and the upper and lower ends of the four main electrodes E1, E2, E3, E4, and the upper and lower guard electrodes G1 and G2. ) by naturally filling the gap between The liquid to be measured cannot move through the gap.

In addition, the fixed epoxy, that is, the surface of the insulator (I) can be reprocessed to the same size as the inner diameter of the case (C) and then inserted into the case (C) to be assembled and fixed.

Therefore, since other measurements are possible only by simple cleaning, it is possible to improve the convenience and efficiency of use, which does not require disassembling, cleaning, and reassembling the electrode every time it is measured, unlike the prior art.

On the other hand, the four main electrodes E1, E2, E3, and E4 are respectively connected to the coaxial cable and lead to the outside, thereby forming a measuring device in which static electricity is completely shielded.

일 때 하기의 수학식 1로 표현된다.The Thompson-Lampard theorem is derived from four main electrodes with a symmetrical structure in vacuum.

When , it is expressed by Equation 1 below.

는 도 2의 주전극 E1과 E3 사이의 전기용량,

는 주전극 E2와 E4 사이의 전기용량을 의미하고,

은 주전극의 길이에 해당된다.here

is the capacitance between the main electrodes E1 and E3 of FIG. 2,

is the capacitance between the main electrodes E2 and E4,

is the length of the main electrode.

)는 하기의 수학식 2로 표현되고, 측정 대상 액체를 제거한 상태, 즉 공기 중의 크로스 커패시턴스(

)는 하기의 수학식 3으로 표현된다.After filling the measurement target liquid in the case (C) of FIG. 3, the cross capacitance (

) is expressed by the following Equation 2, and the state in which the measurement target liquid is removed, that is, the cross capacitance in air (

) is expressed by Equation 3 below.

)가 산출된다.From this, the following Equation 4 is derived, and the dielectric constant of the liquid to be measured (

) is calculated.

는 물리상수로서 0.008854187pF/mm이며 진공의 유전율,

는 공기의 유전상수 1.0006, C_r13은 액체 유전체 시료를 채운 상태에서 주전극 E1과 E3 간의 크로스 커패시턴스, C_r24는 액체 유전체 시료를 채운 상태에서 주전극 E2과 E4 간의 크로스 커패시턴스, C_a13은 액체 유전체 시료를 제거하고 동일한 측정거리의 공기 중에서 주전극 E1과 E3 간의 크로스 커패시턴스, C_a24는 액체 유전체 시료를 제거하고 동일한 측정거리의 공기 중에서 주전극 E2과 E4 간의 크로스 커패시턴스를 나타낸다.here

is a physical constant of 0.008854187 pF/mm and the permittivity of vacuum,

is the dielectric constant of air 1.0006, C _r13 is the cross capacitance between the main electrodes E1 and E3 in the state of filling the liquid dielectric sample, C _r24 is the cross capacitance between the main electrodes E2 and E4 in the state of filling the liquid dielectric sample, and C _a13 is the liquid dielectric The cross capacitance between the main electrodes E1 and E3, _Ca24 , between the main electrodes E1 and E3 in the air at the same measuring distance after removing the sample, represents the cross capacitance between the main electrodes E2 and E4 in the air at the same measuring distance after removing the liquid dielectric sample.

)를 산출한다.Therefore, while the liquid dielectric sample is placed in the case (C), the cross capacitance between E1 and E3 among the four main electrodes is measured, and after measuring the cross capacitance between the main electrodes E2 and E4, the liquid dielectric sample is removed. and measure the cross capacitance between the main electrodes E1 and E3 in the air at the same measurement distance, and substitute the measured value of the cross capacitance between the main electrodes E2 and E4 into Equation 4 to obtain the dielectric constant (

) is calculated.

On the other hand, the results of verification using the dielectric constant CRM for the precision measuring device of the dielectric constant of the liquid dielectric according to the embodiment of the present invention are shown in Table 1 below.

와 공기 중에서 산출된 결과

를 수학식 4에 대입하여 구한 유전상수 값을 CRM 자체의 값과 비교하여 오차를 구하였다. 유전상수 4.0~81.0의 범위에서 측정오차가 0.01~0.03% 수준으로 기존에 비해 매우 우수한 성능을 지니고 있음을 확인하였다.That is, through three-dimensional electric field simulation by a computer program, four types of standard reference material (CRM) samples were directly selected from among liquid dielectrics for which the value of the dielectric constant was already known, inserted between the given electrodes, and the capacitance was calculated.

and the result calculated in air

The value of the dielectric constant obtained by substituting in Equation 4 was compared with the value of CRM itself to obtain an error. It was confirmed that the measurement error was 0.01 to 0.03% in the range of the dielectric constant of 4.0 to 81.0, and it was confirmed that it had a very good performance compared to the previous one.

Here, 4 types of samples serving as CRM (numbers in parentheses are dielectric constants) were used: distilled water (81.0), silicon (4.0), BK (4.8), and RG (10.2).

Therefore, it can be seen that the precision measuring device of the dielectric constant of a liquid dielectric according to an embodiment of the present invention has excellent performance, considering that the conventional device has a dielectric constant measurement error of 1 to 10%.

sample

(CRM)

(CRM) C(E1/E3) C (E2/E4) C(sum)

(meas) U (%) Air 1.0006 0.13853 0.13849 0.27702 - - Distilled water 81 11.215 11.217 22.4320 81.0247 0.0304% silicon 4.0 0.55355 0.55402 1.10757 4.000557 0.0139% BK 4.8 0.66445 0.66458 1.32903 4.800474 0.00988% RG 10.2 1.4123 1.4124 2.8247 10.20285 0.0279%

On the other hand, in the process of verifying the measurement error level of the device for measuring the dielectric constant of a liquid dielectric according to an embodiment of the present invention, if several CRMs with known dielectric constant values are not possessed, one or two CRMs are used as follows. It can be used after correction according to the same procedure.

That is, when a liquid for which the dielectric constant (ε _n ) is already known is put into the accurate dielectric constant measuring apparatus of a liquid dielectric according to an embodiment of the present invention, the measured capacitance (C _n ) and the measured capacitance in air (C _a ) is substituted into Equation 5 below to obtain a calibration value (C _c ).

From this, the correction constant (C _g ) of the electrode structure can be obtained by substituting in Equation 6 below.

Then, the dielectric constant (ε _x ) of the liquid from the capacitance (C _x ) measured value when the measurement target liquid is put is calculated in a corrected state by Equation 7 below.

On the other hand, the length and width of the four main electrodes (E1, E2, E3, E4) and the two guard electrodes (G1, G2) are kept the same in the cylindrical dielectric constant measurement device of the liquid dielectric according to the embodiment of the present invention. The result of confirming the dielectric constant measurement error according to the thickness change through 3D electric field simulation using a liquid standard reference material (CRM) is shown in FIG. 6 .

From this, it is possible to determine and select the thickness of the main electrode and the guard electrode under the condition with the smallest measurement error.

On the other hand, as shown in FIGS. 7 to 9, the cylindrical dielectric constant measuring device of a liquid dielectric according to another embodiment of the present invention has two round-bar Hi electrodes (Hi) and the same diameter (φa) as the Hi electrodes, Two Lo electrodes (Lo) symmetrically arranged, the upper and lower ends of the Hi electrodes (Hi), the upper and lower ends of the Lo electrodes (Lo), and a round bar type guard (G) connected with an insulator (I) between them, respectively , two round-bar-shaped guard electrodes disposed between the Hi electrode (Hi) and the Lo electrode (Lo) and having a diameter (φb) smaller than the diameter (φa) of the Hi electrode (Hi) and the Lo electrode (Lo) and a ground potential (GE), a pair of upper and lower support blocks (S) for grounding the upper and lower ends of the guard (G) and the guard electrodes (GE), and the Hi electrode (Hi) and the Lo electrode (Lo), the guard (G) and the guard electrode It includes a case (C) formed to surround the GEs to block external noise and static electricity, and to contain the liquid to be measured.

The Hi electrode (Hi) and the Lo electrode (Lo) are made of a metal rod and can be respectively combined with the guard (G) using an insulator (I). And it may be electrically insulated by removing the gold plating through wire processing on the lower part.

The guard electrodes GE are fixed to the support block S so that they always have a ground potential when measuring cross capacitance.

In addition, upper and lower ends of the Hi electrode Hi and the Lo electrode Lo are fixed to the support block S to be grounded.

Here, the diameter of the Hi electrode (Hi) and the Lo electrode (Lo) is larger than the diameter of the guard electrode (GE) and the number is set to double the capacitance measurement value in order to measure the dielectric constant of the liquid to be measured much more accurately. in order to increase

In addition, the Hi electrode Hi, the Lo electrode Lo, and the guard electrodes GE are arranged at intervals of 60 degrees with respect to the axis of the case C, so that the measurement error can be minimized by about 0.001 to 0.005%.

In order to ensure that the same capacitance is always measured whenever the Hi electrode (Hi), the Lo electrode (Lo), and the guard electrode (GE) are placed inside the case (C), it consists of a metal body and a lid, and supports three points. can be combined by

Since the Hi electrode (Hi), Lo electrode (Lo), and the guard electrode (GE) can be cleaned simply, it is unnecessary to disassemble, clean, and reassemble each time each measurement.

과 액체 유전체 시료를 제거하고 측정된 전기용량

를 하기의 수학식 8에 대입하면 유전상수

이 산출된다.On the other hand, since the measured value of the cross capacitance between the Hi electrode (Hi) and the Lo electrode (Lo) is measured once, the capacitance measured with the liquid dielectric sample placed in the case (C)

and the liquid dielectric sample were removed and the measured capacitance

By substituting in Equation 8 below, the dielectric constant

This is calculated

How accurate the dielectric constant measurement result using the cylindrical dielectric constant precision measurement device of the liquid dielectric according to another embodiment of the present invention is verified in the same manner as in the above-described embodiment.

와 공기중의 전기용량 측정값

를 수학식 8에 대입하여 구해진 유전상수 값과 CRM 자체의 값을 비교하여 오차를 구하였다. 그 결과는 하기의 표 2에 나타내었다. 측정오차는 0.001~0.005% 수준으로 기존의 방법과 비교할 때 탁월한 성능을 지니고 있음이 확인되었다.That is, the capacitance measurement value after directly inserting 4 types of liquid dielectric standard reference material (CRM) samples whose dielectric constant is known through three-dimensional static electricity simulation by a computer program between the given electrodes.

and capacitance measurements in air

The error was obtained by comparing the value of the dielectric constant obtained by substituting in Equation 8 and the value of CRM itself. The results are shown in Table 2 below. The measurement error is 0.001~0.005%, and it is confirmed that it has excellent performance compared to the existing method.

sample

pF

U (%) Air 1.0006 0.44497 - - Distilled water 81.0 36.022 81.00234 0.0029 silicon 4.0 1.7789 4.000196 0.0049 BK 4.8 2.1346 4.800055 0.0012 RG 10.2 4.5361 10.20028 0.0028

On the other hand, the present invention is not limited by the above-described embodiment and the accompanying drawings, and can be variously modified and applied in various ways not illustrated within the scope without departing from the technical spirit of the present invention, as well as each It is clear to those of ordinary skill in the art to which the present invention pertains that it can be widely applied by changing the component substitution and other equivalent embodiments.

Therefore, the contents related to the modification and application of the technical features of the present invention should be interpreted as being included within the technical spirit and scope of the present invention.

E1, E2, E3, E4: main electrode
G1, G2: guard electrode
I: insulator
C: case

Claims (3)

four main electrodes (E1, E2, E3, E4), which are symmetrically arranged in all directions with a small gap, and have arc-shaped cross-sections; Cylindrical guard electrodes (G1, G2) each having a ground potential with a small gap at the upper end and lower end of the four main electrodes, and having an inner diameter equal to the inner diameter of the four main electrodes; While uniformly maintaining the gap between the four main electrodes and the gap between the four main electrodes and the guard electrode, the electric Cylindrical insulator (I) to insulate with; and a cylindrical case (C) formed to surround an outer peripheral surface (outer curved surface) and a bottom surface of the insulator to shield static electricity and contain a measurement target liquid;
After measuring the cross capacitance between E1 and E3 among the four main electrodes while putting the liquid dielectric sample in the case (C), and measuring the cross capacitance between the main electrodes E2 and E4, the liquid dielectric sample is removed and measure the cross capacitance between the main electrodes E1 and E3 in the air at the same measurement distance, and substitute the measured value of the cross capacitance between the main electrodes E2 and E4 into Equation 4 to obtain the dielectric constant (

), a cylindrical dielectric constant precision measurement device of a liquid dielectric, characterized in that it is calculated.
[Equation 4]

here

is the dielectric constant of air (1.0006),

is the cross capacitance between the main electrodes E1 and E3 when filled with a liquid dielectric sample,

is the cross capacitance between the main electrodes E2 and E4 in the state of filling the liquid dielectric sample,

remove the liquid dielectric sample and cross capacitance between the main electrodes E1 and E3 in air,

shows the cross capacitance between the main electrodes E2 and E4 in air with the liquid dielectric sample removed.
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