JPS5979861A - Static electricity detector - Google Patents

Abstract

PURPOSE:To prevent the deterioration of detection preciseness caused by applying insulating coating to a conductive hollow body, by mounting a means for regulating the resistance of an electric circuit formed in the space between a current collector and the conductive hollow body in said body. CONSTITUTION:A static electricity detection probe 7 is constituted from such a mechanism that a current collector 14 is supported by an insulating support 13 in a metal cylindrical case 12 and an output circuit is further connected to the current collector 14 through a connector resistance 16 while the current collector 14 is connected to the case 12 through high resistance 17. alpha-Rays radiated from the current collector 14 irradiates the bottom surface 11 of a liquid-tight space 10 which is, in turn, ionized to form an electric circuit. The resistance R2 of this circuit is proportional to the distance between the current collector 14 and the bottom surface 11. Therefore, the position to be inserted and mounted of the cylindrical case 12 is adjusted up and down to enable the adjustment of R2. As mentioned above, by properly selecting the position to be inserted and mounted for the case 12, the deterioration of detection preciseness of a conductive hollow body having insulating coating applied thereto can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a static electricity detector that detects static air from a fluid such as a charged liquid, gas, or powder.

The applicants proposed a static air detector of this type, especially for petroleum products. As shown in Figure 1, a current collecting type static electricity detection probe 1 with a built-in current collector having a radioactive substance and an output circuit is intended to detect electric potential.
is fixedly placed (fixed so as not to move) inside a metal ball 3 whose outer periphery is covered with a thin insulating sheath 2, and the static air induced in this metal ball 3 is collected by radiation % separation A1. , a device has already been proposed in which a signal can be collected from the output circuit according to the electric potential of the turtle 9 (Special Publication Publication No. 57).
-1791)).

In this product, the metal H4 ball 3 is coated with an insulating coating 2 in order to prevent corona discharge or spark emission between the metal ball 3 and external strings or objects. There is a concern that if an insulating coating is applied, the detection accuracy will be worse than one without it.

This is due to reasons such as tt'iz.

That is, when the insulating coating 2 is applied, a static capacitance is generated, and this capacitance is C, between the grounded cylindrical case (grounded outer cylinder) of the static glide detection probe 1 and the metal ball 3. Let the so-called floating appearance of R
2, Collection tIf. R is the resistance that keeps the resistance constant.
3, a melting circuit as shown in FIG. 2 is established between the band and the current collector. Note that %V'Id: Input position (
charging potential), Vol; i output potential (current collector detection potential).

As is clear from this equivalent circuit, when the capacitance CI is generated by the insulation p2K, the time constant of the circuit changes, and the output characteristics of vO change, that is, the concentration L{. The responsiveness of the instrument becomes worse.

In order to improve this, the authors have conducted various tests and research, and based on the following experimental results, they have found that even with insulation sheathing 2, the same output characteristics as those without it are produced. Based on this finding, the present invention has been devised to easily compensate for the disadvantages described above due to the use of insulating sheathing.

In other words, the present inventors have developed the SEIZO bulb shown in FIG. 1 which is coated with insulation coating 2 (hereinafter referred to as the insulation coating bulb), and the one shown in FIG. 1 which is different from the one shown in FIG. For this, we made a ball with substantially the same configuration as that (hereinafter referred to as a bare ball), and for the insulated ball, we added the following:
As shown in the circuit of Figure 3, a grounded resistor (earthed resistance) RC with a high resistance value is actively connected, and the value is changed to 10Q+10Q, 10Q, and the other The outer sphere was left unconnected and these spheres were charged to the same predetermined potential, and then the outputs of both static electricity detection gloves were measured.

Figure 4 shows the output characteristics (attenuation transition due to charge movement after charging at a given potential). are shown respectively.

As can be seen from this figure, the output characteristics of the insulating sheath 1 and the bulb change depending on the resistance value of the grounding resistance R<<, and when the grounding resistance R'l is 101jQ, the output characteristics of the bare bulb are almost equal to P1.

This clearly shows that if the value of the grounding resistance Bl is chosen appropriately and the time constant of the circuit is made the same as that of a bare bulb (bare bulb), the same output characteristics as a bare bulb can be obtained. are doing.

Therefore, in the case of the insulated hit ball shown in Fig. 1, if the ground resistance R'8 is connected to the metal ball 3 and its value is adjusted, the detection accuracy of the insulated hit ball can be made equal to that of a bare ball. You will be able to do so.

However, as is clear from the above, the ground resistance is 1
The output characteristics cannot be adjusted unless the value is as high as 012 to 1011 ohms, and it is actually very difficult to adjust this value and produce products with the same detection accuracy.

Therefore, in the equivalent circuit shown in FIG.
It was confirmed through experiments that the time constant of the circuit can also be adjusted by the resistance R (resistance of an electric circuit formed by the action of radiation ionization), and a means for adjusting this resistance R. The present invention has been devised in which it is possible to easily create the same detection accuracy as a bare bulb by providing a conductive hollow body (corresponding to the metal ball 3 in Fig. 1). .

The present invention will be described in detail below with reference to the embodiment shown in FIG.

This static electricity detector has a thin (thickness of 0.5 mm) on the outer peripheral surface (in the hemisphere direction) of a bowl-shaped conductive hollow body 4 made of metal, for example, aluminum.
5 to 0.8 m) A green cover 5 is applied, and the top opening of the conductive hollow hole 4 is closed with a thick disc-shaped insulating support 6, and a collection type static electricity detection probe is attached to this insulating support 6. 7 is supported.

For the insulation coating 5 and the green support base 6, it is preferable to use synthetic bale lubricant that has high coverage and good oil resistance.

In the wooden example, the material of the insulation support 5 is epoxy thermosetting resin, and the material of the insulation support 6 is glass fiber-containing epoxy resin CF. R. P. )It has become.

The insulating support base 6 liquid-tightly closes the upper opening of the conductive hollow body 4 by screwing its male screw 8 into the female screw 9 of the conductive hollow body 4 . Therefore, the inside of the conductive hollow body 4 is a liquid-tight space 1.
It is 0.

The bottom surface 11 of the liquid-tight space 10, which is the inner surface of the conductive hollow body 4, is a horizontal plane without sharp parts. Liquid-tight space 1
The other surface of 0 is also a smooth surface with no sharp parts.

The static electricity detection probe 7 has a current collector 14 supported on an insulating support 13 and an output circuit mounted on a circuit board 15 in a metal cylindrical case (grounded outer cylinder) 12, and furthermore, this output circuit is connected to a coupling resistor 16. The current collector l4 is connected to the cylindrical case 12 via a high resistance 17. The current collector l4 contains americium Am241 (8.8 μCt), which is a radioactive substance. The detection signal leaked by the current collector 14 is amplified and impedance-converted by the output circuit, and then outputted to the outside via a cable 18 connected to this output circuit.

This dilapidated static electricity detection probe 7 has its cylindrical case 12 inserted downward into the mounting hole 19 at the center of the insulating support base 6 so as to be able to slide up and down.
The current collector 1
4 and the bottom surface 11 can be adjusted. The vertical sliding of the cylindrical case 12 with respect to the mounting hole 19 is as follows:
It is regulated by a packing 21 fitted into the four parts 20 formed at the upper end opening of the mounting hole 19 .

The upper bright part of the cylindrical case 12 protrudes from the upper end opening of the mounting hole 19, and the upper end part is connected to the insulating support base 6.
It is liquid-tightly covered by a protective ring 23 made of an insulating material screwed onto the upper surface of the protective ring 23 via a packing 22, and a lid plate 24 made of an elastic material such as rubber screwed onto the upper surface of the protective ring 23. In this example, the retaining ring 23 is made of the same material as the insulating support base 6.

A truncated cone-shaped radiation opening 25 is formed on the lower surface of the insulating support base 6 and continues to the mounting hole 19.
(Lower end opening) Located at the upper end of the cat's radiation mouth portion 25.

A funnel-shaped insulating member 26 made of an insulating material whose insulating properties are somewhat inferior to that of the insulating support base 6 is fitted into the radiation opening 25 . In the case of this example, the material of the insulating part 26 is phenolic resin, and while the resistivity of the insulating support base 6 made of glass fiber-containing epoxy resin is 10"Qan, that of the insulating part 26 is 10” to 10I2QQ%.

A metal diaphragm plate 27 is removably screwed onto the lower end opening of the cylindrical case 12 to substantially reduce the opening area. This crest plate 27 has an aperture hole 28 in its center.

Therefore, the α rays emitted from the americium in the current collector 14 are irradiated onto the bottom surface 11 of the liquid-tight space 10, and the space between the current collector 14 and the bottom surface 11 is ionized, and an electric circuit is formed between them. It is formed. The resistance RS of this electric circuit (the equivalent circuit of this static electricity detector is shown in Fig. 6) is the current collector 1.
4 and the bottom surface 11, and as t increases, R! also becomes larger, and as t becomes smaller, R also becomes smaller. Therefore, the cylindrical case 1 for the mounting hole 19
By vertically adjusting the insertion position of the cylindrical case 120, I6 can be adjusted, and therefore the time constant of the equivalent circuit can also be adjusted.By appropriately selecting the insertion position of the cylindrical case 120, the insulation cover 5 is not applied. It is possible to achieve output characteristics similar to Further, the ionization effect is weakened by the aperture plate 27, and the resistance R in the circuit of FIG. 6 increases by the weakened amount. The degree of weakening is determined by the aperture hole 2
8, and the smaller the value, the stronger the degree of weakening. Therefore, by preparing a plurality of aperture plates 27 with different sizes of aperture holes 28 and using them interchangeably, the resistance R can be adjusted, and therefore the range of measurement potential can also be adjusted (so-called range adjustment). can.

Note that the resistance R changes slightly depending on the diaphragm plate 27 as well.

Since the entire inner circumferential surface of the liquid bud space IO is a smooth surface with no sharp parts, no corona discharge or spark discharge will occur therein, and since the bottom surface 11 is flat, alpha rays will not be generated. can be irradiated evenly, and the static electricity induced in the conductive hollow body 4 can be accurately collected in the current collector 14.

Further, an insulating member 26 made of a material that has a lower resistivity than the insulating support 6 and is less likely to be charged is set around the outer periphery of the radiation port of the static electricity detection probe 7, that is, around the radiation port 25 of the insulating support 6. Therefore, there is no possibility that the insulating support base 6 is charged and the detection accuracy is deteriorated.

In the above embodiment, the resistance R can be adjusted by preparing a plurality of embossed plates 27 with different sizes of aperture holes 28 and using them interchangeably. Adjustment may be made using a variable crest plate whose size can be changed. Also, mesh 5
Adjustments may be made by replacing the number of pieces of wire mesh (detachably attached to the opening at the lower end of the cylindrical case 12).

As described above, the electrostatic detector of the present invention includes a means in the conductive hollow body that can adjust the resistance of the electric circuit formed in the space between the current collector and the conductive hollow body by the radiation iI separating action. Since the sensor is equipped with an insulating coating, it is possible to easily compensate for the disadvantage in detection accuracy caused by applying an insulating coating.

Further, as in the embodiment of claim 3, if the inner surface of the conductive hollow body and the portion that is irradiated with radiation is made flat, the radiation can be irradiated evenly, and the sm. The static electricity induced in the hollow body can be collected into the Hayabusa device.

Furthermore, as in the invention of claim 4 of the first patent, by arranging a metal rod plate or wire mesh with one hole between the inner surface of the conductive hollow body and the current collector, the range of the measured potential can be widened. Easy to adjust.

Furthermore, as in the invention of Claim 5, if an insulating part having a lower resistivity than that of the insulating support is attached around the opening at the tip of the insulating support, the charge in the periphery can be reduced. can be prevented, and detection accuracy can be further improved.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the conventional example, Figure 2 is its equivalent circuit diagram, Figure 3 is an equivalent circuit diagram when a grounding resistor is connected to the metal ball, and Figure 4 is a diagram when the above grounding resistor is connected. Graph 5 showing experimental measurement data for comparing the output characteristics of the conventional example and the manufactured one without insulation coating.
The figure is a sectional view showing an embodiment of the present invention, and FIG. 6 is an equivalent circuit diagram thereof. 14... Current collector, 7... Static electricity detection probe, 4.
... Conductive hollow body, 27... Crest plate, 6... Insulating support base, 26... Insulating member.

Claims (5)

[Claims] 1. A current-collecting electrostatic detection probe equipped with a current collector and an output circuit containing a radioactive object is built into a conductive hollow body with a thin insulation meter on the outer surface, and the probe is equipped with a conductive hollow body with a thin insulation meter on the outside.
1. Does it radiate static electricity? In a WDm air detector in which a current is collected in a collector by a separation action and an electric voltage corresponding to the potential is output from an output circuit, the current collector and the conductor are connected by a distribution radiation network and a separation action. A static electricity detector characterized in that the conductive hollow body is provided with means capable of increasing the resistance of the electric circuit formed in the space between the hollow body and the conductive hollow body. 2. The device according to item 1 of the scope of the patent application, wherein the means capable of reducing resistance is a member that supports the static electricity detection probe so that it can move back and forth in the axial direction K. 3. 2. The electrostatic detector according to claim 1, wherein the inner surface of the hollow body of the electrostatic conductor 1, which is irradiated with the radiation, is made flat. 4. A current-collecting static electricity detection probe equipped with a current collector and an output circuit containing a radioactive object is built into a conductive hollow body with a thin insulating coating on the outer surface, and the static electricity induced in this conductive hollow body is radiated. Current is collected in the collector Wi1 by the ionization effect K,
In an electrostatic detector configured to output an electrical signal according to the potential from an output circuit, electricity is generated in the space between the collector IIIi and the conductive hollow due to the radiation ionization action. A means capable of adjusting the resistance of the circuit is provided in the conductive hollow body, and a metal aperture with a hole is provided between the conducting force, 1h1 of the hollow body, and the current collector. A static electricity detector characterized by being formed by arranging plates or wire mesh. 5. A current-collecting static N1 gas detection probe equipped with a current collector, a device, and an output circuit containing a radioactive object is built into a conductive hollow body with a thin insulation coating on the outer surface, and the static electricity induced in this conductive hollow body is is collected by the current collector K by the action of radiation ionization,
In a static electricity detector configured to output an electrical signal from an output circuit according to the electric potential, electricity (b) is formed in the space between the current collector and the conducting turtle hollow body by the radiation ionization effect. The conductive hollow body is provided with means for adjusting the resistance of the conductive conductor, and the upper JC and the electrostatic discharge probe are supported on the conductive hollow body by an insulating support, and the inner surface of the insulating support is An electrostatic detector characterized in that an insulating member having a lower resistivity than the insulating support base is attached around the tip opening of the tp glans detection probe.