JPH0362487A - Gas-filled discharge tube for high voltage switch element - Google Patents

Abstract

PURPOSE:To stabilize discharge voltage by forming recessed parts on the facing end surfaces of discharge electrodes, and applying a potential falling material for reducing the discharge keeping voltage to the recessed parts. CONSTITUTION:The both end surfaces of an alumina ceramic enclosure of a cylinder having the same size as the outer diameters of flange 10a, 12a are metallized, further plated with Ni, and air-tightly brazed to the flanges 10a, 12a. Trigger lines 16, which are formed on the inner wall of an enclosure 14 by drawing fine lines of carbon on the inner wall, are provided slightly shorter than the protruding lengths of discharge electrodes 10b, 12b from the both end parts of the enclosure 14 toward the central direction of the enclosure 14. A recessed part 18 is provided in the center part of the top end surface of the discharge electrode part 12b of the line electrode 12, and a potential falling material 20 is applied onto the bottom part of the recessed part 18. As this potential falling material 20, for example, those in which 5-50wt.% of BaTiO3 is dispersed in 5-45wt.% aqueous solution of Na2SiO3 are used. As a sealed gas, Kr gas is sealed thereto at 15kg/cm<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a gas-filled discharge tube for a high-voltage switch element that discharges at a high voltage.

(Prior Art) Gas-filled discharge tubes are used in lightning arresters and the like to protect electronic equipment from surges. Fig. 6 is Fig. 9 showing a conventional example of a gas-filled discharge tube used in a detonator. 1 and 2 are line electrodes,
3a and 3b are discharge electrodes, 4 is an envelope, and 5 is a trigger wire provided on the inner wall of the envelope 4. The line electrodes 1 and 2 are hermetically soldered to both end surfaces of the envelope 4 with an inert gas sealed inside the discharge tube.

In gas-filled discharge tubes used in ordinary detonators, etc., the discharge starting voltage is set to about several hundred volts so that surges can be easily avoided, but by increasing the distance between the discharge electrodes, the discharge starting voltage (Vs) can be made approximately 1 okV or more. By stabilizing this high discharge voltage, it becomes possible to use the gas-filled discharge tube as a switching element that switches at high voltage.

To increase the discharge starting voltage of gas-filled discharge tubes.

Usually, it is sufficient to increase the distance between the discharge electrodes or increase the gas pressure to be sealed. For example, when the discharge starting voltage is 20 kV, the distance between the electrodes is 3 m.
m, for example, krypton gas is used as the filler gas at 15k.
Encapsulate at g/cm'.

(Problem to be Solved by the Invention) By the way, depending on the application, high-voltage gas-filled discharge tubes can stably obtain the required discharge starting voltage (Vs) and at the same time be able to extend the discharge time to a certain extent. may be required.

The discharge time is the discharge sustaining voltage (Vd) after the main discharge ends.
serves as a guideline for comparison; the lower the discharge sustaining voltage Vd is, the smaller the energy loss of the discharge tube will be, resulting in a longer discharge time, and the higher the discharge sustaining voltage Vd is, the greater the energy loss will be, resulting in a shorter discharge time. .

Gas-filled discharge tubes used in conventional detonation arresters, etc. have a low discharge starting voltage Vs and a discharge sustaining voltage Vd to improve discharge performance.
However, in the discharge tube targeted by the present invention, it is necessary to make the discharge starting voltage Vs high and the discharge sustaining voltage Vd low.

Therefore, the present invention has been made in view of the above problems, and its purpose is to stably obtain an extremely high discharge starting voltage of 10 kV to 20'/, and to maintain a discharge sustaining voltage. It is an object of the present invention to provide a gas-filled discharge tube for a high-voltage switch element, which can be made low in height, can take a long discharge time, and can improve the durability of a discharge electrode.

(Means for solving problems) The present invention has the following configuration to achieve the above object.

That is, gas is sealed inside the envelope under high pressure, line electrodes are airtightly brazed to both end faces of the envelope, and cylindrical columns are connected from the center of the flange of each line electrode to face each other inside the envelope. A gas-filled discharge tube for a high-voltage switch element having a protruding discharge electrode and discharging at a discharge starting voltage of lokV or more, wherein a recess is formed in the opposite end face of the discharge electrode, and a discharge sustaining voltage is lowered in the recess. It is characterized by being coated with a potential-lowering substance that lowers the potential. The potential lowering substance is BaTi in a 5-45% by weight aqueous solution of Na25iOz.
It is effective to disperse 5 to 50% by weight of 0°.

(Function) The discharge sustaining voltage can be lowered by applying a potential lowering substance into the recess formed on the end face of the discharge electrode.
This lengthens the discharge time, reduces the noise of the discharge tube, stabilizes the discharge voltage, and provides suitable characteristics as a high voltage switching element.

(Embodiments) Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of a discharge tube for a high voltage switch element according to the present invention.

In the figure, 10 and 12 are line electrodes, and a small cylindrical discharge electrode 1 extends from the center of the inner surface of the flanges 10a and 12a, respectively.
0b and 12b are made to protrude facing each other.

Reference numeral 14 denotes an alumina ceramic ring envelope formed into a cylindrical shape having the same size as the outer diameter of the flanges 10a and 12a.

Both end surfaces of the envelope 14 are metallized and further plated with nickel, and the flanges 10a and 12a are brazed airtight.

16 is a trigger wire provided on the inner wall of the envelope 14. This trigger wire 16 is formed by drawing a thin wire made of carbon or the like on the inner wall surface of the envelope 14, and extends from both ends of the envelope 14 toward the center of the envelope 14, respectively, to the discharge electrodes 10b, 12b.
The length should be slightly shorter than the protrusion length. Although the circumferential installation position of the trigger wire is not particularly limited, the discharge electrodes 10b, 1
It is normal to provide them at symmetrical positions with 2b in between.

FIG. 2 is an enlarged cross-sectional view of the line electrode 12. As shown in FIG.
Apply.

In the example, the potential lowering substance 20 is Na25iO:+
An aqueous solution containing 5 to 50 weight percent of BaTi01 was used.

Further, the peripheral edge of the recess 18 of the discharge electrode 12b was formed to have a semicircular cross section.

Note that the line electrode 10 also has the same shape as the line electrode 12.

In the gas-filled discharge tube of the example, the discharge starting voltage was set to 20 kV, and the distance between the discharge electrodes was D = 3 mm.
Projection length IL of discharge electrode = 6.5 mm, flange 10a
, 12a are 16 mm apart. Further, krypton gas was sealed at 15 kg/cm' as a sealed gas.

FIG. 3 shows the results of discharging the gas-filled discharge tube of this example and setting the discharge voltage at that time to Xt++.

The discharge was repeated at 50 Hz. As shown in the figure, the discharge start voltage is approximately 20 kV, and the discharge is stable.

What is the discharge sustaining voltage (Vd) in Figure 4? 111 results are shown. This measurement data shows an enlarged view of the vicinity of completion of discharge in one discharge, and the vertical axis of the figure is the discharge sustaining voltage (Vd), and the horizontal axis is time.

In the figure, part a shows the discharge starting voltage, part b shows the discharge sustaining voltage, and part C shows the state of energy release after the energy supply is turned off.

The standard for discharge sustaining voltage is usually 0.3 kV or less.

As can be seen from the figure, the discharge tube of the example has a discharge sustaining voltage of 0.
．． It has good characteristics at about 1 kV.

FIG. 5 shows, as a comparative example, the results of measuring the discharge sustaining voltage of a discharge tube having the same shape as the above-mentioned example and filled with the same filler gas, but without the potential-dropping substance 20 applied thereto. As you can see from the graph, in this case the discharge sustaining voltage (
In the case of the example shown in Fig. 4, the voltage of part b) is about 0.2 kV, which is inferior in characteristics compared to the above embodiment, large noise appears in part b, and the discharge stop timing of part C is as shown in Fig. 4. There are notable differences, such as a longer delay.

That is, the difference in these effects is considered to be due to the presence or absence of the potential-dropping substance, and by applying the potential-dropping substance, the discharge sustaining voltage Vd can be lowered.

Excellent characteristics such as being able to reduce discharge tube noise can be obtained.

In addition, there is a conventional example in which an active material similar to that used in the above embodiment is applied to the end face of the discharge electrode in a gas-filled discharge tube that discharges at a low voltage. This material improves the performance, lowers the discharge starting voltage Vs, and increases the discharge sustaining voltage Vd, and has an effect different from that of the potential lowering substance of this embodiment.

In addition, in this example, by forming the end face shape of the discharge electrode so that the cross section is arcuate, the surface area of the discharge electrode can be increased, the durability of the discharge electrode can be increased, and the discharge can be This has the effect that a stable discharge voltage can be obtained without being concentrated locally and without variations in the discharge voltage.

The present invention has been variously explained above using preferred embodiments, but the present invention is not limited to these embodiments.
Of course, many modifications can be made without departing from the spirit of the invention.

(Effects of the Invention) The gas-filled discharge tube for high-voltage switching elements according to the present invention has the following features:
As described above, by applying a potential lowering substance to the end face of the discharge electrode, the discharge voltage can be stabilized, and the discharge time can be lengthened by lowering the discharge sustaining voltage Vd.

This has remarkable effects such as being able to obtain a high voltage switching element with excellent characteristics.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an embodiment of the gas-filled discharge tube for high-voltage switching elements according to the present invention, Fig. 2 is a cross-sectional view of a line electrode, and Fig. 3 shows the measurement results of discharge voltage during repeated discharges. Fig. 4 is a graph showing the measurement results of the discharge sustaining voltage, Fig. 5 is a graph showing the measurement results of the discharge sustaining voltage of a comparative example, and Fig. 6 is a graph showing the measurement results of the discharge sustaining voltage of a comparative example. FIG. 4...Envelope, 5...Trigger wire, 10.1
2... Line electrode, 10a, 12a... Flange, 10b, 12b... Discharge electrode, 14... Envelope, 16... L-riga wire, 18... Recessed part, 2
0...Potential lowering substance.

Claims (1)

[Claims] 1. Gas is sealed inside the envelope under high pressure, line electrodes are hermetically brazed to both end faces of the envelope, and a line electrode is inserted into the envelope from the center of the flange of each line electrode. A gas-filled discharge tube for a high-voltage switch element, in which cylindrical discharge electrodes are provided protrudingly facing each other, and a discharge is performed at a discharge starting voltage of 10 kV or more, a recess is formed in the opposite end surface of the discharge electrode, and the recess is A gas-filled discharge tube for a high-voltage switch element, characterized in that the tube is coated with a potential-dropping substance that lowers the discharge sustaining voltage. 2. The gas-filled discharge tube for a high-voltage switch element according to claim 1, wherein the potential lowering substance is a 5-50% by weight aqueous solution of Na_2SiO_3 with 5-50% by weight of BaTiO_3 dispersed therein.