JPH0623783B2 - Detection electrode - Google Patents

Description

The present invention relates to a detection electrode for measuring the electrostatic voltage of a charged object.

There are two methods for measuring the electrostatic voltage of a charged object. One of them is a method of collecting the electric charge from the charged object to be measured and knowing the electrostatic voltage of the charged object to be measured by measuring the potential difference when the electric charge flows to the ground through a high resistance (hereinafter referred to as the current collecting method). The other is a method of placing an electrode of a conductor in an electric field created by an object to be measured and measuring the electrostatic voltage of the object to be measured by using the induced charge generated in the conductor (hereinafter referred to as electrostatic It is called the induction method).

Capacitor type electrostatic voltmeter, which can be used for both current collection method and electrostatic induction method measurement, uses Coulomb force, has a simple structure, has many failures, and is highly reliable for measured values. An instrument, the problem is that it has a small but leaky conductance. In the case of measurement by the current collection method, there is no problem because the charge is replenished, but
The measurement by the electrostatic induction method is limited to a short time when the leakage charge can be ignored.

However, in the measurement by the current collecting method, it is generally desired to use the several-electrical induction method for an object to be measured, which has a slow follow-up to the voltage change of the object to be measured and whose charge state changes rapidly. When using a capacitor-type electrostatic voltmeter, the generation of induced charge by the electrostatic induction method disappears in a short time, and continuous measurement is performed for a long period of time when the next measurement does not leave the induced charge. Although the measurement is not a problem, long-term continuous measurement of an object in which the induced charge is always continuous is impossible by the electrostatic induction method due to the above-mentioned leakage conductance.

The present invention provides a detection electrode for a capacitor-type electrostatic voltmeter that can promptly follow changes in the charging state of a measured charged object and enable long-term continuous measurement.

In the detection electrode of the present invention, one end of a conductive wire is bonded to a conductive fiber layer, and the conductive fiber layer is covered with an insulator with one or a plurality of openings. One end is connected to a condenser-type electrostatic voltmeter to measure the electrostatic voltage of the charged object to be measured.

When the detection electrode having such a structure is placed in an electric field, the insulator causes dielectric polarization, and a charge corresponding to the dielectric polarization is generated in the conductive delicate portion in contact with the insulator. Electric charges due to electrostatic induction are directly generated in the conductive fiber layers in the openings of the insulating material, and charges having different polarities, which are the same as the amount of charges generated in these conductive fiber layers, are transferred to other conductive wires. It is generated at the electrodes of a condenser type electrostatic voltmeter that is connected to the end, and the electrostatic voltmeter operates. On the other hand, a conductive fiber with a fine diameter is exposed in the opening provided in the insulator, so a corona current flows between it and the measured object to replenish the leakage charge due to the leakage conductance of the electrostatic voltmeter. To do. The amount of charge replenished by the corona current is adjusted by the area of the hole of the insulator and the distance of the detection electrode from the charged object to be measured. The present invention will be described 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 condenser type electrostatic voltmeter, and FIG. 2 is an equivalent circuit of FIG.

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

When the detection electrode of the present invention is placed in the electric field generated by the charged electric charge of the measured object 1 to be measured, the insulator covering the conductive fiber layer 4 causes inductive polarization, and the outside is negative and the conductivity is negative. The inner side in contact with the fiber layer 4 is positively polarized, so that a negative electric charge is generated in the conductive fiber layer 4, and the conductive line directly reaches the electric force line from the charged object to be measured at the opening of the insulator. The layer also becomes negatively charged. The same amount of positive charge as the charge generated in these conductive fiber layers is generated in the fixed electrode 6 of the capacitor type electrostatic voltmeter connected to the conductor 5, and this charge activates the electrostatic voltmeter.

However, since the electrostatic voltmeter has a leak conductance, the electric charge generated in the fixed electrode decreases, and therefore the indication of the electrostatic voltmeter decreases unless the electric charge is replenished.

This replenishment of the electric charge is performed by the opening 3 of the coating insulator 2 of the detection electrode.
Conducted by the conductive fibers exposed to the. Due to the fine size of the conductive fiber, the density of the lines of electric force is high, and therefore a corona current is generated. The corona current replenishes the electric charge escaping from the fixed electrode 6 of the condenser type electrostatic voltmeter.

An equivalent circuit of this is shown in FIG. Of Figure 2
C ₁ is the capacitance between the charged object to be measured and the detection electrode, g ₁ is the conductance with respect to the corona current between the charged object to be measured and the detection electrode, and C ₂ and g ₂ are the capacitance type electrostatic voltmeters respectively. Capacitance and leakage conductance.

If the static voltage of the charged object to be measured is E, and no current flows in g ₁ and g ₂ , the electrostatic voltmeter The final indication of the electrostatic voltmeter is Becomes Therefore, if each conductance can be taken to be proportional to each capacitance, the instruction obtained by electrostatic induction does not change, and a quick instruction can be obtained.

Capacitance-type electrostatic voltmeter itself has a change in capacitance, but the amount of change is relatively small, so by keeping the conductance proportional to each capacitance as much as possible, the final value can be set relatively quickly. It can approach the indicated value.

The conductance g ₁ is adjusted by the type of conductive fiber, the size of the opening, the distance from the charged object to be measured, etc., and the conductance g ₂ is adjusted by adding a conductance for adjustment. be able to. The capacitance C ₁ can be changed according to the size of the detection electrode, the distance between the object to be measured and the detection electrode, the amount of conductive fibers, and so on. Select and use.

Therefore, the detecting electrode of the present invention may have various shape dimensions, and FIG. 3 shows an embodiment.

In the embodiment of FIG. 3, a conductive fiber layer 4 is provided around an insulator pipe 6 for holding the shape of the electrode, and the outer side thereof is covered with an insulating shrink tube 2 having an opening 3. Then, the conductive wire 5 is coupled to one end of the conductive fiber 4.

[Brief description of drawings]

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. FIG. 3 is a perspective view showing an embodiment of the detection electrode of the present invention.

Claims (1)

[Claims] 1. An outer surface of a conductive fiber layer bonded to a conductor,
Capacitor type electrostatic voltmeter detection electrode covered with an insulator having one or more openings.