JPH0362483A - Gas-filled discharge tube for high voltage switch element - Google Patents

Abstract

PURPOSE:To enable the stable discharge at high voltage by sealing Kr gas into a gas-filled discharge tube between high voltage switch elements at a pressure of 11-20kg/cm<2>. CONSTITUTION:The both end surfaces of an alumina ceramic enclosure 14 formed into a cylinder of the same size as the outer diameter of flanges 10a, 12a are metallized and further plated with Ni, and the flanges 10a, 12a are air-tightly brazed thereto. The enclosure 14 has trigger lines 16 on the inner wall, and the trigger lines 16, which are formed by drawing fine lines of carbon on the inner wall surface of the enclosure 14, 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. Kr gas is sealed into the thus-sealed discharge tube at a pressure of 11-20kg/cm<2>, whereby the space between electrodes of the discharge electrodes can be set to about 3mm, and the discharge starting voltage can stably be discharged at 10-20KV.

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. 4 shows a conventional example of a gas-filled discharge tube used in a lightning arrester. In the figure, 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 1.2 are hermetically brazed to both end surfaces of the envelope 4 with an inert gas sealed inside the discharge tube.

Gas-filled discharge tubes used in ordinary detonators, etc., have a discharge starting voltage of several hundred volts to easily avoid surges, but by increasing the distance between the discharge electrodes, the discharge starting voltage can be increased. can be increased to about 10 kV or more. By utilizing this high discharge voltage, it becomes possible to use the gas-filled discharge tube as a switching element for switching at high voltage.

Since the discharge starting voltage (Vs) becomes a function of the product of the gas pressure P and the distance between the discharge electrodes under a constant gas temperature (Paschen's law), the distance between the discharge electrodes increases the gas pressure. It is possible to make it smaller by doing this. In a gas-filled discharge tube used in a normal detonator, the distance between the electrodes is about 1 mm, and the pressure of the filled gas is about 250 mmHg.

(Problem to be Solved by the Invention) In order to increase the discharge starting voltage of a gas-filled discharge tube, it is necessary to increase the distance between the electrodes or to fill in gas at high pressure due to the above-mentioned conditions. However, if the distance between the electrodes is increased too much, the discharge sustaining voltage (Vd) will increase and energy loss will increase, making it unsuitable for stable discharge.
It is necessary to increase the pressure of the filled gas and reduce the distance between the discharge electrodes.

Additionally, as the discharge starting voltage increases, creeping discharges tend to occur along the inner wall surface of the envelope, so it is necessary to suppress unnecessary discharges such as creeping discharges by using an appropriate filler gas. . This is because if creeping discharge occurs, the discharge occurs before reaching a predetermined voltage, resulting in problems such as not being able to obtain the necessary discharge voltage or causing variations in the discharge voltage. Furthermore, since the envelope is made of a dielectric material such as ceramic, there is a problem in that creeping discharge tends to occur at high voltages.

Conventionally, the discharge starting voltage was set at a gas pressure of 10 kg/cm'
It was believed that if the voltage exceeds 10 kg/cm2, it will no longer contribute effectively to Vs, but the inventor conducted a discharge experiment with gas sealed at a pressure of 10 kg/cm2 or higher, and found that the discharge starting voltage was 10 kV or more.
A gas-filled discharge tube that stably discharges at an extremely high voltage of 20 kV was obtained.

That is, one object of the present invention is to provide a gas-filled discharge tube for a high voltage switching element that stably discharges at an extremely high voltage of 10 kV to 20 kV.

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

That is, in a gas-filled discharge tube for a high-voltage switch element in which gas is sealed at high pressure inside and line electrodes are hermetically brazed to both end faces of the envelope, krypton gas is charged into the discharge tube at 11 kg/kg. am2~20kg/c
It is characterized by being sealed at a pressure of m'.

(Function) By filling the discharge tube with krypton gas at high pressure, the interval between the discharge electrodes can be set to about 3 mm, and stable discharge can be performed at a discharge starting voltage of 10 kV to 20 kV.

(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, which are small cylindrical discharge electrodes located at the center of the inner surfaces of the flanges 10a and 12a, respectively]
, Ob, and 12b are made to protrude facing each other.

Reference numeral 14 denotes an alumina ceramic envelope formed into a cylindrical shape having the same size as the outer diameter of the flanges 10a and 12a. Both end faces of the enclosure 4 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.

In the gas-filled discharge tube of the example, the discharge starting voltage was set to 20 kV, the distance between the discharge electrodes D = 3 mm, the protrusion length of the discharge electrodes Q = 6.5 mm, the flange ■Qa,
The distance between the inner surfaces of 12a is 16 mm. In addition, krypton gas is used as the sealed gas, and it is charged at 15 kg/c.
It was enclosed in m'.

FIG. 2 shows the results of discharging the gas-filled discharge tube of this example and measuring the discharge voltage at that time. The discharge was repeated at 50Hz, and as shown in Figure 6, the discharge was approximately 20k.
Stable discharge could be obtained at a discharge voltage of V.

Figure 3 is a graph showing the measurement results of the discharge sustaining voltage.
The vertical axis of the figure is the discharge sustaining voltage (Vd), and the horizontal axis is time. The discharge sustaining voltage (Vd) is a measure of the energy that the discharge tube maintains between the end of the main discharge and the first discharge.The lower the discharge sustaining voltage, the less energy loss occurs and the more the discharge is induced. This means that the discharge tube can be maintained in this condition for a long time. Conversely, if the discharge sustaining voltage is high, energy will be lost in a short time, and the time for maintaining discharge will be shortened. Therefore, the lower the discharge sustaining voltage, the better the characteristics of the discharge tube.

Figure 3 is an enlarged view of the voltage axis for measuring the discharge sustaining voltage, where part a is the discharge starting voltage, part b is the point at which the discharge voltage has decreased (discharge sustaining voltage), and part C is when the energy supply is turned off. This shows the energy release state after the The standard for discharge sustaining voltage (Vd) is usually 0.3 kV or less. As can be seen from the figure, the example has good characteristics with a discharge sustaining voltage of 0.1 kV. Since krypton gas quickly eliminates ions, it also works to lower the discharge sustaining voltage.

Part C is noise generated from the high voltage generator.

The above experimental results show that the krypton gas sealing pressure is 15 kg.
/cm2, the distance between the discharge electrodes was 3 mm to 5 mm, and the krypton gas filling pressure was 1 kg/cm2 to 20 kg/cm.
'By setting the discharge starting voltage to 10 kV to 26
It was confirmed that similarly stable and repeated discharges could be made in the kV range. It was also confirmed that these cases also had low discharge sustaining voltages and excellent characteristics.

The above experimental results show that krypton gas at 11 kg/cm'
It has been shown that by sealing at a pressure of m2 to 20 kg/cm', it is effective to discharge at a high voltage of about 10 kV to 20 kV.

Note that the inert gas used may be krypton gas, argon gas, or other gases, or a mixture thereof.

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 can store krypton gas at 11 kg/cm' to 20 kg/a.
10kV to 20k by enclosing at high pressure of m'
It can be stably discharged at a high voltage of about V, has a low discharge sustaining voltage as mentioned above, and has excellent repeated discharge characteristics, and can be effectively used as a high-voltage switching element. Effective.

[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 graph showing the measurement results of the discharge voltage during repeated discharges, and Fig. 3 is the discharge sustaining voltage. FIG. 4 is a cross-sectional view showing a conventional gas-filled discharge tube used as a detonator. 4...Envelope, 5...Trigger wire, 10.12...
- Line electrode, 10a, 12a... flange. iob, 12b...Discharge electrode, 14...Envelope, 16...Trigger wire. Figure 2 ], 2a Figure

Claims (1)

[Claims] 1. In a gas-filled discharge tube for a high-voltage switch element, in which gas is sealed at high pressure and line electrodes are hermetically brazed to both end faces of an envelope, the inside of the discharge tube includes: krypton gas at 11kg/cm^2~20
A gas-filled discharge tube for a high voltage switch, characterized in that it is sealed at a pressure of kg/cm^2.