JP4126161B2 - Lightning arrester for communication - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lightning arrester (gas arrester) for communication that is installed in a communication line and absorbs an excessive surge such as lightning entering the communication line to protect devices connected to the communication line. The present invention relates to a lightning arrester for communication suitable for superimposed communication lines.
[0002]
[Prior art]
It is known to use a gap type lightning arrester in order to protect devices and the like connected to the communication line from excessive surges such as lightning that has entered the communication line. In addition, when a DC power supply is superimposed on the communication line, in order to prevent continuity, a gap type lightning arrester is used in combination with a resistor such as a varistor to It is also known to protect and interrupt the continuity. Furthermore, since a gap type lightning arrester has a time delay at the start of discharge, a structure in which a carbon wire is attached along with the discharge gap to improve the discharge start time delay is also known. Furthermore, it is also known that a gap type lightning arrester has a low glow voltage (voltage between terminals during discharge operation) and is liable to generate a follow-up current. Still further, it is also known to use iron, nickel, kovar, copper or the like as the electrode material.
[0003]
[Problems to be solved by the invention]
Today, the progress of communication technologies such as mobile phones and the Internet is remarkably fast, and communication circuits are shifting from analog to digital. Along with this, the frequency used is also shifted to a higher frequency band, but the required frequency band of the conventional frequency band is at most about MHz and at most less than 1 GHz. However, at present, the frequency band is as high as 1 to 3 GHz. However, as the frequency increases, the transmission loss and reflection characteristics (VSWR) improve, the discharge start time delay at high frequencies improves, the measures against the continuity against the power supply voltage superimposed on the communication line, and the current withstand capability improves. Etc. are required.
[0004]
By the way, when trying to improve the delay of the discharge start time, the carbon wire or the like attached to the inner peripheral wall of the insulating tube is affected, so that the transmission loss and the reflection characteristic (VSWR) loss are increased, or the frequency band When the current withstand is increased and the current withstand is increased, there is a problem that one improvement leads to the occurrence of other problems such as lowering the glow voltage and facilitating the generation of a follow-up current.
[0005]
An object of the present invention is to solve the problems of the above-described conventional communication lightning arrester.
[0006]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides an insulating tube mainly composed of cylindrical alumina having openings at both ends, and carbon having a line width of 1 mm or less attached to the inner peripheral wall of the insulating tube. Wire and a pair of copper electrodes having a flat discharge surface, and the pair of electrodes is insulated so that a discharge gap between the opposed discharge surfaces is 0.4 to 0.7 mm. The space is closed by the insulating tube and the pair of electrodes, and a mixed gas of argon and hydrogen is sealed in the opening of the tube, and the discharge The concave portion formed on the discharge surface of the part is filled with a mixture as a discharge active material having a composition of 90 to 95% by volume of molybdenum and 5 to 10% by volume of auxiliary material .
[0007]
【Example】
Hereinafter, examples of the present invention will be described. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.
[0008]
Reference numeral 1 denotes a communication lightning arrester. The communication lightning arrester 1 mainly includes a cylindrical insulating tube 2, a carbon wire 3 attached to an inner peripheral wall 2a of the insulating tube 2 at a predetermined interval, and a cylindrical The space 5 is composed of substantially disk-shaped electrodes 4 fitted in the openings at both ends of the insulating tube 2, and the space 5 closed by the pair of electrodes 4 facing the insulating tube 2 is filled with gas. Has been. The carbon wire 3 is attached so as not to contact the electrode 4, and is attached to the inner peripheral wall 2a of the insulating tube 2 at intervals of 90 degrees along the axial direction of the insulating tube 2, for example. Has been. The insulating tube 2 is mainly composed of alumina, and the carbon wire 3 has a line width of 1 mm or less, and in many cases has a line width of about 0.5 mm and is attached linearly. The interval between the carbon wires 3 is not limited to an angle of 90 degrees.
[0009]
The electrode 4 covers the annular horizontal portion 4a, the cylindrical portion 4b extending downward from the inner peripheral edge of the annular horizontal portion 4a, and the lower end of the cylindrical portion 4b, and forms a flat discharge surface 4c1. The discharge part 4c is formed of a copper material.
[0010]
A discharge gap 6 is formed between the discharge surfaces 4c1 of the pair of opposed electrodes 4 that are fitted in the openings at both ends of the insulating tube 2. The interval between the opposing discharge gaps 6 is 0.4 to 0.7 mm, and the gas enclosed in the space 5 closed by the insulating tube 2 and the electrode 4 is mainly composed of argon and has a capacity of 40 with respect to argon. %, Preferably 3 to 40% by volume of hydrogen.
[0011]
A large number of recesses 4d are formed on the discharge surface 4c1 of the electrode 4, and the discharge activation material 7 is filled in the recesses 4d. In this embodiment, the discharge activator made of molybdenum alone is powdered and press-fitted into the recess 4d formed on the discharge surface 4c1 of the electrode 4. As the discharge activator 7, in addition to molybdenum, a simple substance such as manganese, niobium, tantalum, tungsten, aluminum, or a compound thereof can be used. Moreover, cellulose acetate, polyvinyl alcohol, polyvinyl butyrol, etc. can also be mixed with the discharge activation material 7 as an auxiliary material. In this embodiment, a mixture of 90 to 95% by volume of molybdenum as the discharge activation material 7 and 5 to 10% by volume of a mixture of cellulose acetate, polyvinyl alcohol, and polyvinyl butyrol as auxiliary materials is used. ing.
[0012]
In the communication lightning arrester 1 having the above-described configuration, in the frequency band of 300 KHz to 3 GHz, the reflection characteristic (VSWR) is 1.2 or less, the insertion loss is suppressed to -0.2 dB or less, and the current withstand is an impulse current waveform. in 8 / 20μs, it was achieved 50KA. Furthermore, as a continuity test, even if a 100 A impulse is applied to the power circuit under a condition where a DC voltage of 52 V and a current of 5 A are supplied, the continuity is interrupted in a time of 7.6 ms or less. did.
[0013]
As described above, the carbon wire 3 is attached to the inner peripheral wall 2a of the insulating tube 2 so as not to contact the electrode 4, and the carbon wire 3 is formed to be long and narrow as described above. The discharge gap 6 is about 0.4 to 0.7 mm, and the gas sealed in the space 5 closed by the insulating tube 2 and the electrode 4 is mixed with hydrogen as the main component argon. Furthermore, due to the synergy of the electrode 4 being made of a copper material, the synergy of the disposition of the discharge activation material 7 mixed with auxiliary materials on the discharge surface 4c1 of the electrode 4 as necessary. Thus, the conventional frequency band up to about MHz can be expanded to 3 GHz band, and the glow discharge voltage is increased from about 50 V or lower to about 180 to 200 V. Can Impulse current withstand also what was conventionally 5～10K A, can be a 20 ~50K A, furthermore, it was able to avoid the occurrence of the conventional follow current.
[0014]
【The invention's effect】
The present invention achieves the following effects by the configuration described above.
[0015]
The range of use can be expanded to a high frequency band, the current withstand capability can be increased several times that of the prior art, and the occurrence of continuity can be suppressed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a communication lightning arrester according to an embodiment of the present invention.
[Explanation of symbols]
1 ... Lightning arrester for communication 2 ... Insulation tube 3 ... Carbon wire 4 ... Electrode 6 ... ... Discharge gap

Claims (1)

A pair of copper-made insulating pipes having an opening at both ends, mainly composed of cylindrical alumina, a carbon wire with a line width of 1 mm or less attached to the inner peripheral wall of the insulating pipe, and a flat discharge surface Each of the pair of electrodes is fitted into each opening of the insulating tube so that a discharge gap between the opposed discharge surfaces is 0.4 to 0.7 mm. In addition, a mixed gas of argon and hydrogen is sealed in the space closed by the insulating tube and the pair of electrodes, and molybdenum formed in the recess formed on the discharge surface of the discharge portion. A lightning arrester for communication, which is filled with a mixture as a discharge active material having a composition of 90 to 95 vol% and auxiliary material 5 to 10 vol% .

Images