JPS59177880A - Lightning tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a gas-filled discharge tube in which an inert gas is hermetically sealed, and particularly to a discharge tube that starts discharge in a short time.

This invention relates to a lightning arrester that is suitable for use in protecting communication equipment, etc. from lightning surges.

(2) Background of the technology Traditionally, when a lightning surge (different high voltage caused by lightning) flows into a communication line, a lightning arrester discharges between the electrodes and sends the surge to the ground, raising the voltage of the communication device.

It has the role of protecting against large currents.

What type of arrester is used to configure such a protection circuit?

The desired discharge is performed even in response to repeated surges.

After the surge is released, it is necessary to immediately supply normal power supply voltage to the circuit, so the discharge of the detonator must be stopped immediately. 2 O~ which is the current range normally supplied by two circuits
At 0.3 A, glow discharge occurs, and the glow discharge sustaining voltage must be higher than the power supply voltage supplied from the circuit.

This is because if the arc discharge occurs at 0 to 0.3 A, the arc discharge voltage is usually about 15 to 25 V, and the discharge continues at the 9-circuit voltage. The arc transition current of the current detonator is 0.5~1. Since it is OA,
There is no need to worry about follow-on current caused by arc transfer (after the arrester discharges due to a lightning surge, the discharge continues due to the circuit voltage, causing the arrester to overheat and cause a communication failure or fire), but the equipment Depending on the type, a power supply voltage of about 150 μm may be used, and there is a demand for a detonator that has a high glow discharge sustaining voltage and is difficult to follow.

(3) Prior art and problems Figure 1 shows a two-pole arrester. The electrode parts 1 and 2 are made of iron-nickel-cobalt alloy (Kovar), 42-nickel alloy (42 alloy), etc., the insulator 7 is made of glass or ceramic, and the inside 6 is filled with an inert gas.8. 8
' is hermetically sealed using a known sealing technique such as silver source sealing.

The electrode facing surfaces 3 and 4 may be made of the electrode material as it is, such as Kovar or 4270I, or an oxide of an alkali metal or alkaline earth metal such as sodium or barium, or carbonate, taking into consideration the surface energy during discharge. There are also commercially available products that have the surface coated with

In the case of a detonator whose electrode surface is made of the electrode metal material, if it is subjected to repeated surges.

The electrode metal sputters and adheres to the inner wall of the insulator, resulting in poor insulation between the electrodes and deteriorating performance. On the other hand, those coated with alkali metals and alkaline earth metals are strong against repeated surges, but because the discharge sustaining voltage is as low as 40 to 80V, the power supply voltage of the equipment to be protected is around 100V. In this case, the following flow described above will occur, making it unusable.

In addition, there are products on the market that have a structure in which a glass material is deposited on the surface and the discharge sustaining voltage is relatively high, but the manufacturing method is difficult, and when repeated surges are applied, the discharge starting voltage becomes much erratic compared to the initial stage. This has drawbacks such as discharging at a constant voltage and causing surges to enter the equipment to be protected, resulting in damage to the equipment.

(4) Purpose of the Invention In order to solve the problems in the prior art, the present invention provides a detonator with a high discharge sustaining voltage (no follow-up) and whose discharge starting voltage does not change even during repeated surges. The purpose is to

(5) Structure of the Invention The present invention is achieved by fixing a metal oxide having a high normal cathode drop voltage to the electrode surface.

The normal cathode drop voltage is the voltage drop at the cathode when the discharge tube performs glow discharge, and the value varies depending on the material of the cathode and the discharge body.

(6) Examples of the invention The present invention will be explained in detail below.

In Figure 1, the outer diameter is 3 mm and the height is llmrn.
A polar detonator is used, and 42 alloy is used as the electrode.

Alumina ceramic is used as the insulator 7, and a mixed gas of 30% argon and 70% neon is used as the filling gas, taking into account the width of the discharge gap 5 so that the discharge starting voltage is about 300 V DC. 8. The seal at 8' is soldered by conventional methods. That is, both end faces of the alumina ceramic 7 are made Mmeo-MnMn, and the electrodes 1.2 and 2 are separated by about 80% by silver source.
It is heated in an electric furnace at 00°C and hermetically sealed.

Under this manufacturing assumption, in the present invention, the electrode is subjected to the following treatment in the 6 [J adjustment process.

(Method of applying uranium 1,1 oxide to the electrode facing surface) Dissolve uranyl acetate powder in water to make a 1011i aqueous solution, and as shown in FIG.
4 is coated with uranyl acetate aqueous solution 9.

Dry this at room temperature. Next, when this electrode is used, uranium acetate is thermally decomposed into W, liberating acetic acid groups, and becoming uranium oxide, but due to the decomposition atmosphere, UO, U20
3. It can take various forms such as UOg, U205, UO3,9 and the present invention is also a mixture of some of these oxides. According to the results of differential thermal analysis, thermal decomposition was completed at 370°C.

Furthermore, in the process of increasing the temperature to 800° C. for sealing, sintering of the uranium oxide is performed to form a uranium oxide layer that has good adhesion to the electrode.

(2) Method of forming manganese oxide in close contact with the surface facing the electrode In the same manner as in (1), prepare a 10% aqueous solution of manganese sulfate and use the second method.
As shown in the figure, it is painted with a brush, and manganese sulfate is thermally decomposed in a brazing furnace to liberate SO2 and SOB, forming manganese oxide (MnO, Mn02) that has good adhesion to the electrode.

Examples of oxides of elements having a large normal cathode drop voltage according to the present invention include Cu and Ag, which are members of the royal family of the periodic table.

V group Nb, Sb, Bi, Vl group Cr, Mo, WVl
There are M n of the I group, Ire, Ni, Co of the II group, and Th and U of the actinium series, but these oxide powders alone cannot provide strong adhesion to the electrode, and all of them are difficult to maintain at the sintering temperature. Because of the high temperature, it is necessary to sinter at temperatures of 800°C or higher to improve adhesion to the electrodes, and some materials decompose into metals during heating, which complicates the manufacturing process.

If the adhesion with the electrode is poor, ions f! li
The electrode was blown away by the blow, and the electrode base material came to the surface and sputtered, adhering to the insulator.

This is not possible because the insulation resistance will deteriorate.

In order to increase the adhesion with the electrode, 1) Apply a thin film (~100μ) on the electrode surface as an aqueous organic solvent solution according to the present invention.
It is best to make the electrode at a brazing temperature of 800°C.

There is also a method of depositing an element with a large normal cathode drop voltage on the electrode and then oxidizing it in an oxidizing atmosphere, but this method has drawbacks such as the resulting oxide layer being too thin and the amount of oxidation being difficult to control. Relatively good results can also be obtained by reducing the particle size of the oxide and lowering the sintering temperature. For example, if mankan oxide powder particle size (0.5 to 1μ) is suspended in water at 10% by weight and applied to the electrode, the repeated repetition of manganese sulfate aqueous solution will be lower than when it is applied as a manganese sulfate aqueous solution. The results were quite good, although slightly inferior to the previous one. Possible means for forming close contact include vapor deposition of these oxides, thick film printing, spot welding, and brazing.

Next, we will show the results of a comparison of the electrical characteristics of a detonator with uranium oxide and manganese oxide closely formed on the electrode facing surface and a conventional detonator.

For the following current test I, the measurement circuit shown in Figure 3 was used with a DC bias of 150 V, 0.2 A, and a surge of 10 x 1'000 μ.
5. When conducting an experiment at 200 A, it was observed that both the conventional detonator (10) using an alkali metal oxide and the detonator 10 using an alkaline earth metal oxide had a follow current of more than i 50 m s. However, no follow-up current was observed in any of the detonators using uranium oxide, manganese oxide, and glass.

Next was uranium oxide and manganese oxide, which did not follow.

Each surge arrester 10 using glass material is connected to 10 x 1000 I7 S 2 in the surge repeating circuit shown in Fig. 4.
A surge repetition of 0OA was applied 200 times, and the DC discharge starting voltage was measured at the initial stage and after the repetition. The result is the fifth
As shown in the figure. The initial DC discharge starting voltages were all the same so that accurate comparison could be made. FIG. 5 plots the values before and after repetition of a detonator using glass material, and there is a large variation after one repetition, ranging from 200V to 650V. Figures 6 and 7 are graphs showing the DC discharge starting voltage before and after repetition of detonation arresters using uranium oxide and manganese oxide, respectively.Even after repetition, there is little variation from 250V to 250V.
It was confirmed that the distribution was within 370 square meters, and that it was sufficiently durable for use.

On the other hand, uranium compounds are designated as nuclear fuel controlled substances, but they can be used easily if they are notified to the Science and Technology Agency. The depleted uranium compound (238U) used here emits only alpha rays and no beta rays or T rays, so it has little effect on the human body when handled.

No special attention is required. This uranium is α
It is thought that this contributes to stabilizing the DC discharge starting voltage for emitting wires.

Experiments were conducted using various oxides with large normal cathode drop voltages (TiO2, pb○, La20B) using the treatment method in the example.
, PbO, Co, 504. Fe2O3, Cuo, Cr2
03. SnO, ZnO, CeO2).

In terms of tendency, the better the adhesion to the electrode after treatment, the larger the molecular weight and the greater the energy absorption ability, the better the results were obtained.

Furthermore, there is a method of increasing the normal cathode drop voltage by mixing nitrogen gas or the like with the inert gas, but this was not possible due to large variations in the DC discharge starting voltage after repeated surges.Mixing inert gases 1. For example, were there any combinations that slightly increased the normal cathode drop voltage, such as changing the mixing ratio of argon and neon, or mixing with helium, xenon, krypton, etc.?
Since the voltage is about 10 to 30 V, gasification becomes high, so it is not a very good method, and changing the gas mixture ratio can only adjust the DC discharge starting voltage. In other words, it is known that enclosing a large amount of debris will prolong the repeated life, so the type of debris that can enclose the maximum amount of debris to obtain the desired DC discharge starting voltage.

/'Ju LL is the best choice.

In this embodiment, an example of a two-pole arrester is shown, but it is obvious that the present invention can also be applied to a multi-pole arrester with three or more poles.

(7) One advantage of the invention is that by firmly adhering a metal oxide with a high normal cathode effect voltage to the electrode facing surface, a lightning arrester in which the discharge starting voltage does not change even after repeated flashing without following current. The tube is i47.

1 is a cross-sectional view of the electrode surface coated with a solution for oxide formation according to the present invention, FIG. 3 is a follow-on current measurement circuit, FIG. 4 is a Zahn repeating circuit, and FIG. Each of these is a detonation arrester using conventional glass material.

The amount of paddy and the amount of DC discharge after repetition of the detonator according to the present invention using uranium oxide and manganese oxide are shown in a 1° diagram showing the rice pressure.

In the figure, 1 and 2 are electrodes, 3 and 4 are electrode pairs, 5 is a discharge camp, 6 is an inert gas enclosure chamber, 7 is an insulator, and 8 is Sa
(=J section, 10 indicates the detonator main body.

1,・-1,g“j

Claims (1)

[Claims] In a gas-filled discharge tube type detonator, in which the discharge electrodes are arranged opposite to the opposite ends of the insulator and hermetically sealed, and a discharge space is formed between the discharge electrodes, A detonator characterized by closely forming an oxide of an element with a large normal cathode drop voltage.