JPH01311585A - Discharge type surge absorbing element - Google Patents

Abstract

PURPOSE:To increase the current withstand quantity and reduce the discharge delay time by connecting a trigger discharging piece made of a material with the good creeping discharge characteristic in parallel with a discharging gap. CONSTITUTION:A trigger discharging piece 5 is formed in an airtight container 3, a discharging gap 4 and the trigger discharging piece 5 are connected in parallel. The trigger discharging piece 5 is formed by depositing a material with the good creeping discharge characteristic on the inner face of an envelope 3a constituting the airtight container 3 in a film shape by means of deposition, flame coating, coating or the like. When a material mainly made of nickel oxide is used for the material constituting the trigger discharging piece 5, the creeping discharge is easily formed in particular. The trigger discharging piece 5 may be formed on part of the inner face of the envelope 3a as well as on the whole area of the inner face of the envelope 3a.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a discharge-type surge absorption element that utilizes a discharge phenomenon in a discharge gap enclosed in an airtight container, and is particularly applicable as a trigger means for an air discharge. The present invention relates to a discharge type surge absorbing element that improves response characteristics by using creeping discharge.

[Prior art] Conventionally, in order to protect electronic circuit components from transient abnormal voltages and surges such as induced lightning that enter electronic equipment, varistors made of voltage nonlinear resistors and discharge gaps sealed in airtight containers have been used. Various surge absorbing elements are used, such as gas arresters that utilize this phenomenon.

Among the conventional surge absorbing elements described above, a gas arrester, which is a type of discharge type surge absorbing element l, has a discharge electrode 2.2 made of a metal or the like with good discharge characteristics, as shown in FIG. 5(A).
are sealed to both ends of an outer envelope 3a made of an insulating material to form an airtight container 3, and the airtight container 13 is filled with discharge gas to form a discharge gap 4 between the discharge electrodes 2 and 2. It has a formed structure. In addition, the gas arrester has a fifth
As shown in Figure (B), the rod-shaped discharge electrodes 2.2 are placed opposite each other to form a discharge gap 4, which is sealed together with a discharge gas in an airtight container 3 made of a processed glass tube or the like.
There is also a structure in which a lead wire 6.6 is led out from 2.

When a surge is applied to the discharge type surge absorbing element, an arc discharge is generated in the discharge gap through an air discharge, that is, a glow discharge, and the surge is absorbed through the large current of the arc discharge.

[Problems to be Solved by the Invention] As described above, the discharge type surge absorption element absorbs surges through aerial discharge, and therefore has a large current withstand capacity, but has a long discharge delay time and a steep rise. There is a problem in that a residual surge is generated in response to a surge having characteristics, and surge protection cannot be provided sufficiently.

The present invention has been devised in view of the above-mentioned points, and takes advantage of the advantages of the surge absorption element using air discharge and improves the disadvantages, thereby achieving a large current withstand capacity and a short discharge delay time. The purpose of this invention is to realize a discharge-type surge absorbing element that can exhibit a sufficient protective function even against rapidly rising surges.

[Means for Solving the Problem] As a result of various studies to achieve the above-mentioned object, we focused on the fact that the discharge delay time of creeping discharge is extremely small, and by using this as a trigger means for aerial discharge, we have achieved the present invention. It has been completed.

Therefore, the discharge type surge absorbing element of the present invention has discharge electrodes facing each other to form a discharge gap between the electrodes, and a trigger discharge electron made of a material having good creeping discharge characteristics is connected in parallel to the discharge gap. This is sealed in an airtight container filled with discharge gas. As the above-mentioned material having good creeping discharge characteristics, a material containing nickel oxide as a main component is suitable.

The trigger discharge electron may have an auxiliary discharge electrode on at least its surface, and the auxiliary discharge gap formed between the auxiliary discharge electrode and the discharge electrode may be narrower than the discharge gap between the discharge electrodes. good.

Furthermore, the position where the trigger emission electrons are formed can be determined at any position within the airtight container! For example, it can be formed on the inner surface of an airtight container or on the surface of an insulator interposed between discharge electrodes.

[Operation] When a surge is applied to the discharge type surge absorbing element configured as described above, a creeping corona discharge is immediately generated on the trigger discharge surface between the discharge electrodes, and surge absorption is started. The creeping corona discharge acts as a trigger discharge, and due to the priming effect of electrons and ions accompanying the discharge, it transitions to an air discharge in the discharge gap. Therefore, arc discharge is generated in the discharge gap through glow discharge, and the surge is absorbed through the large current of the arc discharge.

In addition, when an auxiliary discharge electrode is provided on the surface of the trigger discharge electron to form an auxiliary discharge gap, the creeping corona discharge generated on the surface of the trigger discharge electron first becomes an air discharge in the narrow auxiliary discharge gap. Further, this aerial discharge transfers to the discharge gap between the discharge electrodes. In this case, the transition time from the above-mentioned creeping discharge to the air discharge in the auxiliary discharge gap is ＼Since the auxiliary discharge gap is narrower than the discharge gap between the discharge electrodes, the transition time from the creeping discharge in the absence of the auxiliary discharge electrode to the above-mentioned discharge This is much shorter than the transition time of the air discharge in the gap.

Moreover, the transition of the air discharge from the auxiliary discharge gap to the discharge gap takes a very short time due to its priming effect, since the air discharge in the auxiliary discharge gap generates a larger amount of electrons and ions than the creeping discharge. It will be held in Therefore, the transition time from the creeping discharge to the air discharge in the discharge gap is shortened.

Furthermore, if the trigger discharge electron is formed on the inner surface of the airtight container, there is no need to separately prepare a member to support the trigger discharge electron.
Furthermore, if the trigger discharge electrons are formed on the surface of the insulator interposed between the discharge electrodes, the discharge path of the creeping corona discharge becomes shorter.

[Example] Hereinafter, the present invention will be described in detail based on the drawings.

[Example 1] FIG. 1 is a sectional view showing a discharge type surge absorbing element according to an example of the present invention. In the figure, a discharge type surge absorbing element 1 has a discharge electrode 2.2 made of a metal material with good discharge characteristics, such as nickel, iron, or an alloy thereof, connected to both ends of an envelope 3a made of an insulating material such as ceramic. to form an airtight container 3, and the discharge electrodes 2 facing each other.
．． A discharge gap 4 is formed between the two, and a trigger discharge electron 5 is formed on the inner surface of the airtight container 3, and the discharge gap 4 and the trigger discharge electron 5 are connected in parallel. A discharge gas made of rare gas, nitrogen gas, sulfur hexafluoride gas, etc. is sealed in the airtight container 3, and a lead wire 6.6 is connected to the outer surface of the discharge electrode 2.2 constituting the airtight container 3. Ru.

The trigger emission electrons 5 are produced by depositing, thermal spraying, or spraying a material having good creeping discharge characteristics on the inner surface of the envelope 3a constituting the airtight container 3.
It is formed by applying it in the form of a film by means such as coating, and is connected in parallel to the discharge gap 4 by connecting its end to the discharge electrode 2°2. In this case, the material constituting the trigger discharge electrons 5 may be any material as long as it has good creeping discharge characteristics, but when a material containing nickel oxide as a main component is used, the formation of creeping discharge is particularly difficult. It becomes easier. Furthermore, in addition to forming the trigger discharge electrons 5 over the entire inner surface of the outer envelope 3a, the same triggering effect can also be obtained by forming them in a linear shape, for example, on a part of the inner surface of the outer envelope 3a.

Further, in order to increase the triggering effect, the trigger discharge electron 5 may have a structure in which an auxiliary discharge electrode 7 is formed on the surface thereof, as shown in FIG. The discharge auxiliary electrode 7 is made of a metal with good discharge characteristics, such as copper, nickel, or aluminum.
When the main component is nickel oxide and nickel is used as the auxiliary discharge electrode 7, it is possible to form the nickel oxide at the same time using the same raw material in the process of depositing the nickel oxide on the airtight container 3, which simplifies the process. can be achieved. Also,
The auxiliary discharge electrode 7 needs to be provided at a position such that the auxiliary discharge gap 8 formed between the auxiliary discharge electrode 7 and the discharge electrode 2 is narrower than the discharge gap 4 between the discharge electrodes 2. There is. This can be easily formed by sparsely depositing a plurality of metal particles or lumps of metal on the surface of the trigger discharge electron 5. In this case, depending on the method of forming the auxiliary discharge electrode 7, the metal used as its material may be mixed with the material having good creeping discharge characteristics that constitutes the trigger discharge electron 5, but the amount of the metal mixed in is such that it does not cause conductivity. If so, there is no problem.

[Example 2] FIG. 3 is a cross-sectional view showing a discharge type surge absorbing element according to another example of the present invention. The discharge type surge absorbing element 1 of this example is arranged so that the discharge type surge absorbing element 1 faces each other across a discharge gap 4. discharge electrode 2,
An insulator 9 such as ceramic is placed between the insulator 9 and the insulator 9.
Trigger discharge electrons 5 are formed on the surface of the discharge gap 4.
and a trigger discharge electron 5 are connected in parallel, and this is sealed together with a discharge gas in an airtight container 3 made of an insulating material such as glass.
The lead wires 6, 6 connected to the discharge electrode 2.2 are drawn out. The other configuration of this embodiment is the same as that of the first embodiment. In the case of this embodiment, the creepage distance between the discharge electrodes 2 on the surface of the insulator 9 is shorter than the creepage distance on the inner surface of the airtight container 3.

[Example 3] FIG. 4 is a sectional view showing a discharge type surge absorbing element according to still another example of the present study. The discharge type surge absorbing element 1 of this embodiment is made of nickel, copper, aluminum, etc.
A metal material with good discharge characteristics is processed into a rod or plate shape, and an emitter material such as barium oxide or lanthanum hexaboride is applied to the surface of the metal material to form a pair of discharge electrodes 2.2. A lead wire 6.6 made of dumet wire (copper-coated iron-nickel alloy wire), 42-6 alloy wire, etc. is connected.

Further, the lead wires 6.6 are aligned in the same direction, and the discharge electrodes 2.2 are arranged substantially parallel to each other so that the discharge electrodes 2.2
A discharge gap 4 is formed between them, a trigger discharge electron 5 is connected in parallel to the discharge gap 4, and this is sealed together with a discharge gas in an airtight container 3 made of glass, and one end of the airtight container 3 is penetrated. A lead wire 6°6 is led out to the outside.

The trigger discharge electron 5 is formed by adhering to the inner surface of one end of the airtight container 3, and is connected to the discharge electrodes 2, 2 via lead wires 6.6 and connected in parallel to the discharge gap 4. The other configuration of this embodiment is the same as that of the first embodiment.

In the case of this embodiment, since the discharge electrode 2.2 is not in contact with the airtight container 3, even if the electrode 2.2 is heated to a temperature that melts the surface of the discharge electrode 2.2, the airtight container 3 is not likely to be thermally deformed. Therefore, when the trigger discharge electrons have nickel oxide as a main component and nickel is selected as the material constituting the discharge electrode 2.2, for example, high-frequency heating is performed in a reduced pressure oxidizing atmosphere. Similarly, the discharge electrode 2
The surface of .degree. 2 can be melted and scattered, oxidized, and applied to the inner surface of the airtight container 3 as nickel oxide. In this case, if conditions such as the heating temperature and the concentration of the oxidizing atmosphere are controlled so that part of the nickel is deposited without being oxidized, it is possible to simultaneously form the auxiliary discharge electrode 7 using this nickel. Further, the auxiliary discharge electrode 7 is
It can also be formed by scattering a metal constituting the lead wire 6.6 or the emitter material, such as copper or barium, and depositing it on the surface of the trigger discharge electron 5. In this case, the emitter material is formed by thermally decomposing a raw material (barium carbonate), such as barium oxide, deposited on the discharge electrode 2.2, and exhausting the decomposed impurities (carbon dioxide) together with air. In some cases, the auxiliary discharge electrode 7 and the emitter material can be formed in the same process by simply adjusting the heating conditions. Therefore, in these cases, there is no need to separately prepare materials and processes for forming the trigger discharge electron 5 and the auxiliary discharge electrode 7, and manufacturing can be simplified.

[Effects of the Invention] As detailed above, the discharge type surge absorbing element of the present invention has trigger discharge electrons made of a material with good creeping discharge characteristics connected in parallel with the discharge gap, so that when a surge is applied, Immediately, a creeping corona discharge occurs on the surface of the trigger discharge electron, and this serves as a trigger, and the creeping discharge changes to an air discharge in the discharge gap, that is, a glow discharge, and then to an arc discharge. Therefore, the discharge-type surge absorption element of the present invention has surge absorption characteristics that combine the continuity of creeping discharge and the large current withstand capability of arc discharge, and can exhibit a sufficient protective function against steep surges. Become something. In this case, if the trigger discharge electrons are formed using a material containing nickel oxide as a main component, the trigger effect will be particularly large because nickel oxide has excellent creeping discharge characteristics.

In addition, by providing an auxiliary discharge electrode on the surface of the trigger discharge electron to form an auxiliary discharge gap narrower than the discharge gap between the discharge electrodes, creeping corona discharge can transition to air discharge in the auxiliary discharge gap. , and further migrates to the discharge gap between the discharge electrodes. In this case, the transition time of the discharge described above is shortened due to the narrow auxiliary discharge gap and the large briming effect due to the aerial discharge in the auxiliary discharge gap, so the discharge time in the trigger discharge is shortened. . Therefore, deterioration of the trigger discharge electrons due to creeping discharge is prevented, and the life characteristics are improved.

Furthermore, by forming the trigger discharger on the inner surface of the airtight container, there is no need to prepare a separate member to support the trigger discharger, so that manufacturing becomes simple. Furthermore, by forming trigger discharge electrons on the surface of the insulator interposed between the discharge electrodes, the discharge path of the creeping corona discharge becomes shorter, so that the discharge transition time is shortened and the life characteristics are improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, 2nd TI! J is an enlarged sectional view showing an example of the configuration of the trigger discharge electron, and FIG.
FIG. 4 is a sectional view of still another embodiment of the present invention, and FIGS. 5(A) and 5(B)
is a sectional view of a conventional example. l...Discharge type surge absorption element, 2.2...Discharge electrode, 3...Airtight container, 4...Discharge gap, 5...Trigger discharge electron, 7...Auxiliary discharge electrode, 8 ...Auxiliary discharge gap, 9...Insulator. Patent applicant: Okaya Electric Industry Co., Ltd.

Claims (5)

[Claims] (1) In a discharge type surge absorbing element in which discharge electrodes are opposed to each other to form a discharge gap between the electrodes and this is enclosed in an airtight container filled with discharge gas, the discharge gap has creeping discharge characteristics. 1. A discharge type surge absorbing element characterized in that trigger discharge electrons made of a good material are connected in parallel and sealed in the airtight container. (2) The discharge type surge absorbing element according to claim 1, wherein the material having good creeping discharge characteristics is mainly composed of nickel oxide. (3) The trigger discharge electron has an auxiliary discharge electrode on at least its surface, and the auxiliary discharge gap formed between the auxiliary discharge electrode and the discharge electrode is narrower than the discharge gap between the discharge electrodes. The discharge type surge absorbing element according to claim 1 or 2, characterized in that: (4) The discharge type surge absorbing element according to claim 1, 2 or 3, wherein the trigger discharge electron is formed on the inner surface of the airtight container. (5) Claim 1, 2 or 3, characterized in that the trigger discharge electrons are formed on the surface of an insulator interposed between the discharge electrodes.
The discharge type surge absorption element described in .