JPS61235755A - Detection electrode - Google Patents

Abstract

PURPOSE:To perform continuous measuring operation for a long period by measuring a static voltage by a capacitor type electrostatic voltmeter formed by covering a conductive fiber layer coupled with a conductor with an insulator which has one or plural opening parts. CONSTITUTION:A detection electrode is constituted by providing the conductive fiber layer 4 around an insulator pipe 6 in an electrode shape and sheathing its outside with the insulating shrinkable tube 3 which has one or plural opening parts 3; and the conductor 5 is coupled with one end of the conductive fiber 4. This detection electrode is connected to the capacity type electrostatic voltmeter and a static voltage voltage is measured to perform continuous measuring operation for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detection electrode for measuring electrostatic voltage of a charged object.

There are two methods to measure the electrostatic voltage of a charged object. One method is to collect electric charge from the charged object to be measured and measure the potential difference when the electric charge flows to the ground through a high resistance (hereinafter referred to as the current collection method). ), and the other method is to place a conductive electrode in the electric field created by the charged object to be measured, and use the induced charge generated in the conductor to measure the electrostatic voltage of the charged object to be measured (hereinafter referred to as electrostatic induction). It is called law.

Capacitor-type electrostatic voltmeters utilize Coulomb force, can be used for both current collection measurement and electrostatic induction measurement, and have a simple structure, less failure, and high reliability of measured values. Although it is a meter, the problem is that it has leakage conductance, although it is small. In the case of measurement using the current collection method, there is no problem since the charge is replenished, but the measurement using the electrostatic induction method is limited to a short time period in which leakage charge can be ignored.

However, when measuring by the current collection method, it is generally slow to follow the voltage change of a charged object to be measured, and it is preferable to use the electrostatic induction method for a measured object whose charged state changes quickly. When using a capacitor-type electrostatic voltmeter, the induced charge generated by the electrostatic induction method disappears in a short period of time, and the induced charge does not remain in the next measurement for a continuous long period of time. There is no problem with measurements, but long-term continuous measurements on objects where induced charges are constantly sustained are difficult due to the leakage conductance mentioned above, depending on the electrostatic induction method.
It's impossible.

The present invention provides a detection electrode for a capacitor-type electrostatic voltmeter that can quickly follow changes in the charging state of a charged object to be measured and enables continuous measurement over a long period of time.

The detection electrode of the present invention has one end of a conductive wire bonded to a conductive fiber layer, and this conductive fiber layer is covered with an insulating material with one or more openings. One end is connected to a capacitor-type electrostatic voltmeter to measure the electrostatic voltage of the charged object to be measured.

When a detection electrode with such a structure is placed in an electric field, dielectric polarization occurs in the insulator, and a charge corresponding to the dielectric polarization is generated in the delicate conductive portion that is in contact with the insulator. Charges are generated directly in the conductive fiber layers in the openings of the insulator due to electrostatic induction, and charges with a different polarity and an amount equal to the charge generated in these conductive fiber layers are generated in the conductive wire. It is generated at the electrode of the capacitor-type electrostatic voltmeter connected to the other end, and the electrostatic voltmeter is activated. On the other hand, since conductive fibers with a fine diameter are exposed in the opening provided in the insulator, a corona current flows between the charged object and the charged object to be measured, replenishing the leakage charge caused by the leakage conductance of the electrostatic voltmeter. do. The amount of charge replenishment by the corona current is adjusted by the area of the hole in the insulator and the distance from the charged object to be measured between the detection electrode. This invention will be specifically explained in more detail with reference to the drawings.

FIG. 1 is a schematic diagram for explaining the function when the detection electrode of the present invention is connected to a capacitor type electrostatic voltmeter, and FIG. 2 is an equivalent circuit of FIG. 1.

In FIG. 1, reference numeral 1 denotes a charged object to be measured, which in this case is assumed to be positively charged. 2 covers the conductive fiber layer 4 with an insulator having openings 3. One end of a conductive wire 5 is connected to the conductive fiber layer 4, and the other end is connected to a fixed electrode of a capacitor type electrostatic voltmeter. The movable electrode 7 of the capacitor type electrostatic voltmeter is grounded.

When the detection electrode of the present invention is placed in an electric field generated by the charged charge of the charged object 1 to be measured, the insulating material covering the conductive fiber layer 4 causes induced polarization, and the outside becomes negative and the conductive The inner side that is in contact with the fiber layer 4 is positively polarized, so a negative charge is generated in the conductive fiber layer 4, and the conductive fiber is directly reached by the lines of electric force from the charged object to be measured at the opening of the insulator. The layer is also negatively charged. A positive charge equal to the charge generated in these conductive fiber layers is generated on the fixed electrode 6 of the capacitor-type electrostatic voltmeter connected to the conductive wire 5, and the electrostatic voltmeter is activated by this charge.

However, since the electrostatic voltmeter has leakage conductance, the charge generated on the fixed electrode decreases, and if the charge is not replenished, the reading on the electrostatic voltmeter will decrease.

The replenishment of this charge is caused by the opening 3 of the insulating coating 2 of the detection electrode.
This is done by conductive fibers that are exposed to the Due to their fine size, conductive fibers have a high density of electric lines of force, thus generating corona currents. This corona current replenishes the charge that escapes from the fixed electrode 6 of the capacitor type electrostatic voltmeter.

This is shown in an equivalent circuit as shown in FIG.

In Figure 2, C1 is the electrostatic capacitance between the charged object to be measured and the detection electrode, 1 gl is the conductance for the corona current between the band to be measured and the molded object and the detection electrode, and C2 and g2 are each a capacitor-type electrostatic voltmeter. are the capacitance and leakage conductance of

If the electrostatic voltage of the charged object to be measured is E, it becomes g++g2 −
When no current flows, the electrostatic voltmeter shows a voltage of lE C5+ C2, but the final reading of the electrostatic voltmeter is .

J g+ + g2. Therefore, if each conductance can be made proportional to each capacitance, the indication obtained by electrostatic induction will not change and a quick indication can be obtained.

A capacitor type electrostatic voltmeter itself changes in capacitance, but the amount of change is relatively small, so by making the conductance proportional to each capacitance as much as possible, the final result can be determined relatively quickly. It is possible to get close to the indicated value.

Adjustment of conductance g1 should be carried out by adjusting the type of conductive fiber, size of the opening, distance from the charged object to be measured, etc., and adjustment of conductance g2 should also be done by adding a conductance for adjustment. Can be done. In addition, the capacitance CI can be changed depending on the size of the detection electrode, the distance between the charged object to be measured and the detection electrode, the amount of conductive fibers, etc., so select an appropriate detection electrode depending on the situation at the measurement site. Use selectively.

Therefore, the detection electrode of the present invention may have various shapes and sizes, and one embodiment is shown in FIG.

In the embodiment shown in FIG. 3, a conductive fiber layer 4 is provided around the insulating vibro to maintain the electrode shape, and the outside of the conductive fiber layer 4 is covered with an insulating shrink tube 2 having an opening 3. , a conductive wire 5 is coupled to one end of the conductive fiber 4.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining the function when connected to the detection electrode capacitor type electrostatic voltmeter of the present invention.
FIG. 2 is an equivalent circuit diagram of FIG. 1. FIG. 3 is a perspective view showing one embodiment of the detection electrode of the present invention.

Claims (1)

[Claims] A detection electrode for measuring static voltage with a capacitor-type electrostatic voltmeter, in which the outside of a conductive fiber layer bonded to a conductive wire is covered with an insulator having one or more openings.