JP2017107680A - Surge protective element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surge protective element capable of suppressing generation of CO and a COgas due to electric discharge, and suppressing operation destabilization.SOLUTION: A surge protective element comprises an insulation tube 2, a pair of sealing electrodes 3 for sealing a discharge control gas inside the insulation tube by blocking openings at both ends of the insulation tube, and a discharge auxiliary part 4 formed of a carbon material on an inner peripheral surface of the insulation tube. The pair of sealing electrodes includes a pair of protruding electrode parts 5 protruding inward and facing to each other. CO generation blocking parts 6A and 6B containing an element easier to be combined with oxygen in comparison with carbon are formed on the inner peripheral surface of the insulation tube.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a surge protection element used for protecting various devices from a surge caused by a lightning strike and preventing accidents.

  Abnormal voltage such as lightning surge and static electricity, etc., such as parts where electronic devices for communication equipment such as telephones, facsimiles and modems are connected to communication lines, power lines, antennas or image display drive circuits such as CRTs, liquid crystal televisions and plasma televisions A surge protection element is connected to a portion that is easily subjected to electric shock due to (surge voltage) in order to prevent damage due to thermal damage or ignition of an electronic device or a printed circuit board on which the device is mounted due to abnormal voltage.

  Conventionally, as shown in Patent Document 1, for example, an arrester-type surge protection element having a pair of protruding electrode portions protruding in a facing state from a pair of sealing electrodes and having a discharge auxiliary portion formed on the inner surface of an insulating tube is provided. Have been described. Usually, in such a surge protection element, a discharge auxiliary portion made of a carbon material is formed on the inner surface of an insulating tube facing an intermediate region between a pair of protruding electrode portions. Such a discharge auxiliary portion is generally formed of a conductive ion source material such as graphite and serves as an ion source for promoting initial discharge.

Utility Model Registration No. 3151069

The following problems remain in the conventional technology.
In the conventional structure, the discharge auxiliary part is damaged and sublimated by the heat and expansion energy at the time of arc discharge generated between the pair of protruding electrode parts, and the discharge voltage at the time of repeated discharge is unstable (the discharge voltage increases). ). Furthermore, carbon (C) that has sublimated and disappeared from the discharge auxiliary part combines with oxygen (O) in silica or the like melted and sublimated from the insulating tube to generate CO and CO ₂ gas, which greatly increases the discharge start voltage. Cause it to rise.
In particular, in the discharge of a large current, the sublimation disappearance of the discharge auxiliary part tends to become remarkable. Also, if the discharge current greatly exceeds the guaranteed range, it is required to change the design of the electrode, and for stable operation, measures such as increasing the size or connecting in parallel are required. There was an inconvenience that was necessary.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a surge protection element capable of suppressing the generation of CO and CO ₂ gas due to discharge and suppressing the instability of operation. To do.

  The present invention employs the following configuration in order to solve the above problems. That is, the surge protection element according to the first invention includes an insulating tube, a pair of sealing electrodes that closes both ends of the insulating tube and seals a discharge control gas therein, and the insulating tube. A discharge auxiliary portion formed of a carbon material on the inner peripheral surface of the insulating tube, and the pair of sealing electrodes have a pair of protruding electrode portions that protrude inward and face each other, and the inner peripheral surface of the insulating tube In addition, a CO production-inhibiting portion containing an element that is more easily bonded to oxygen than carbon is formed.

In the surge protection element of the present invention, the CO generation inhibition portion containing an element that is more easily bonded to oxygen than carbon is formed on the inner peripheral surface of the insulating tube. Therefore, the element included in the CO generation inhibition portion Can be combined with oxygen (O) sublimated from the insulating tube to absorb oxygen and suppress generation of CO and CO ₂ gas.

According to a second aspect of the present invention, the surge protection element according to the first aspect is characterized in that the CO generation inhibiting portion is formed in the vicinity of the discharge assisting portion.
That is, in this surge protection element, since the CO generation inhibiting portion is formed in the vicinity of the discharge assisting portion, the CO generation inhibiting portion absorbs oxygen (O) sublimated from the insulating tube near the discharge assisting portion. Thus, generation of CO and CO ₂ gas can be further suppressed.

According to a third aspect of the present invention, the surge protection element according to the first or second aspect is configured such that the CO generation inhibiting portion is formed in an annular shape extending over the entire circumference of the inner peripheral surface of the insulating tube. Features.
That is, in this surge protection element, the CO generation inhibiting portion is formed in an annular shape extending over the entire inner peripheral surface of the insulating tube, so that oxygen is absorbed over the entire inner peripheral surface of the insulating tube. can do.

A surge protection element according to a fourth invention is the surge protection element according to any one of the first to third inventions, wherein the CO generation inhibiting part is formed of a core part composed of the element that easily binds to oxygen and an insulating material. And a coating film that covers the core part.
That is, in this surge protection element, the CO generation inhibiting portion is composed of a core portion made of the element that is easily bonded to oxygen and a coating film that is formed of an insulating material and covers the core portion. Since the core part is protected by the coating film, the disappearance of sublimation of the core part due to discharge can be suppressed, and the CO production inhibition mechanism can be maintained.

The present invention has the following effects.
That is, according to the surge protection element according to the present invention, the CO generation inhibition portion containing an element that is more easily bonded to oxygen than carbon is formed on the inner peripheral surface of the insulating tube. The element contained in the carbon can be combined with the carbon (C) sublimated from the discharge auxiliary portion to absorb the carbon and suppress the generation of CO and CO ₂ gas. This can prevent a significant increase in the discharge start voltage during repeated discharge.
Therefore, even if the surge current and the number of discharges increase, it is possible to maintain the surge protection element performance satisfactorily. In particular, the surge protection element according to the present invention is suitable for power supplies and communication facilities for infrastructure (railway-related, renewable energy-related (solar cell, wind power generation, etc.)) that require high current surge resistance.

It is sectional drawing of the axial direction which shows 1st Embodiment of the surge protection element which concerns on this invention. It is AA arrow sectional drawing of FIG. It is sectional drawing of the principal part which shows 2nd Embodiment of the surge protection element which concerns on this invention. FIG. 4 is a cross-sectional view taken along line B-B in FIG. 3. It is sectional drawing of the principal part which shows 3rd Embodiment of the surge protection element which concerns on this invention. It is sectional drawing of the principal part which shows 4th Embodiment of the surge protection element which concerns on this invention. It is sectional drawing of the principal part which shows the other example of 2nd Embodiment.

  Hereinafter, a first embodiment of a surge protection element according to the present invention will be described with reference to FIGS. 1 and 2. In each drawing used for the following description, the scale is appropriately changed in order to make each member recognizable or easily recognizable.

As shown in FIGS. 1 and 2, the surge protection element 1 of this embodiment includes a pair of seals that close the insulating tube 2 and both ends of the insulating tube 2 and seal the discharge control gas inside. A stop electrode 3 and a discharge auxiliary portion 4 formed of a carbon material on the inner peripheral surface of the insulating tube 2 are provided.
The pair of sealing electrodes 3 has a pair of protruding electrode portions 5 that protrude inward and face each other.
In addition, CO generation inhibition portions 6A and 6B containing an element that is more easily bonded to oxygen (O) than carbon (C) are formed on the inner peripheral surface of the insulating tube 2.

The CO generation inhibiting part 6A is formed in the vicinity of the discharge assisting part 4.
That is, the discharge auxiliary part 4 is formed in a straight line along the axis C of the pair of protruding electrode parts 5, and the CO generation inhibiting part 6 A is in the vicinity of the discharge auxiliary part 4 and is located in the discharge auxiliary part 4. It is formed linearly along.
Further, the CO production inhibiting portion 6B is formed in a spherical shape, a polygonal shape, or the like, and is dispersedly attached to the inner peripheral surface of the insulating tube 2.

As the elements contained in the CO production inhibiting units 6A and 6B, elements that are more stable than the production of 2C + O ₂ = 2CO are selected based on the Ellingham diagram showing the relationship between the temperature and the standard production Gibbs energy. The element that is most easily bonded to oxygen and becomes a stable oxide as compared with carbon is Ca. In addition, metal elements such as Mg, Li, Al, Ti, Si, V, Mn, and Cr (about 1300 ° C. or higher) can be employed. These elements constitute the CO production inhibiting units 6A and 6B as a single metal or a mixture with other metal elements.
As a method for forming the CO generation inhibiting portions 6A and 6B, for example, metal powder (Ti powder or the like) of the element is attached to the inner peripheral surface of the insulating tube 2, or a member formed of the element is fitted. By doing so, it is good also as CO production | generation inhibition part 6A, 6B.

The discharge auxiliary portion 4 is a conductive material, and is formed of, for example, a carbon material.
The insulating tube 2 is a cylindrical member formed of a crystalline ceramic material such as alumina. The insulating tube 2 may be a glass tube such as lead glass.

The sealing electrode 3 is made of, for example, 42 alloy (Fe: 58 wt%, Ni: 42 wt%), Cu, or the like.
The sealing electrode 3 has a disk-like flange portion 7 that is fixed in close contact by a heat treatment with a conductive adhesive (not shown) at both ends of the insulating tube 2. A cylindrical protruding electrode portion 5 that protrudes inward and has an outer diameter smaller than the inner diameter of the insulating tube 2 is integrally provided inside the flange portion 7.

The conductive fusing material is formed of, for example, an Ag—Cu brazing material as a brazing material containing Ag.
The discharge control gas sealed in the insulating tube 2 is an inert gas or the like, for example, He, Ar, Ne, Xe, Kr, SF ₆ , CO ₂ , C ₃ F ₈ , C ₂ F ₆ , CF ₄ , H ₂ , air, etc. and mixed gas thereof are used.

  In this surge protection element 1, when an overvoltage or overcurrent enters, an initial discharge is first performed between the discharge auxiliary portion 4 and the protruding electrode portion 5, and the discharge further develops triggered by this initial discharge. Discharge is performed between the flange portions 7 or between the protruding electrode portions 5.

As described above, in the surge protection element 1 of the present embodiment, the CO generation inhibition portions 6A and 6B containing an element that is easier to combine with oxygen than carbon are formed on the inner peripheral surface of the insulating tube 2. The elements contained in the CO production inhibiting units 6A and 6B can be combined with oxygen (O) sublimated from the insulating tube 2 to absorb oxygen and suppress generation of CO and CO ₂ gas.
Further, since the CO generation inhibition units 6A and 6B are formed in the vicinity of the discharge auxiliary unit 4, the oxygen (O) sublimated from the insulating tube 2 by the CO generation inhibition units 6A and 6B in the vicinity of the discharge auxiliary unit 4. The generation of CO and CO ₂ gas can be further suppressed.

  Next, second to fifth embodiments of the surge protection element according to the present invention will be described below with reference to FIGS. Note that, in the following description of the embodiment, the same components described in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

The difference between the second embodiment and the first embodiment is that, in the first embodiment, the CO production inhibiting portions 6A and 6B are formed in a linear shape, a spherical shape or a polygonal shape, whereas the second embodiment is different from the second embodiment. In the surge protection element 21, as shown in FIGS. 3 and 4, the CO generation inhibiting portion 26 is formed in an annular shape that extends over the entire inner peripheral surface of the insulating tube 2.
The axis (center line) of the CO production inhibiting unit 26 is the same as the axis C of the insulating tube 2.

  The CO generation inhibiting portion 26 is formed in both of the pair of electrode facing regions A1 facing the outer peripheral surfaces of the pair of protruding electrode portions 5, and is a region between the pair of electrode facing regions A2 on the inner surface of the insulating tube 2. A2 is an area where the CO production inhibiting unit 26 does not exist. By not forming the CO generation inhibition part 26 in this region A2, it is possible to suppress the CO production inhibition part 26 from being directly affected by arc discharge and sublimation disappearance.

  Thus, in the surge protection element 21 of the second embodiment, the CO generation inhibiting portion 26 is formed in an annular shape extending over the entire circumference of the inner peripheral surface of the insulating tube 2. Oxygen can be absorbed over the entire circumference.

Next, the difference between the third embodiment and the second embodiment is that, in the second embodiment, one CO generation inhibiting portion 26 is formed in one electrode facing region A1, whereas the third embodiment is different from the third embodiment. In the surge protection element 31 of the embodiment, as shown in FIG. 5, three CO generation inhibition portions 36 are formed in one electrode facing region A1 with a space in the direction along the axial direction. is there.
Therefore, in the surge protection element 31 of the third embodiment, a plurality of the CO generation inhibition portions 36 are formed in the direction along the axial direction of the insulating tube 2, so the direction along the axial direction of the insulating tube 2. In this case, even if one CO production inhibiting unit 36 is damaged, other CO production inhibiting units 36 maintain the CO production inhibiting function well, and a stable operation can be obtained even during repeated discharge.

  Next, the difference between the fourth embodiment and the first embodiment is that the CO production inhibiting portion 6B is formed of only elements that are more easily bonded to oxygen than carbon, whereas the fourth embodiment is different from the fourth embodiment. In the surge protection element 41, as shown in FIG. 6, the CO generation inhibiting portion 46 is formed of a core portion 46a made of the element that easily binds to oxygen, and a coating that is formed of an insulating material and covers the core portion 46a. It is a point comprised by the film | membrane 46b.

That is, the CO production inhibiting part 46 of the fourth embodiment includes a core part 46a having a spherical or polygonal shape formed of a metal element such as Ca, Mg, Li, Al, Ti, Si, V, Mn, Cr, It is a composite formed of a coating film 46b formed of an insulating material such as ceramics that covers the core 46a. For example, the core 46a made of Ti or the like is covered with a coating film 46b made of TiO ₂ , SiO ₂ , Al ₂ O ₃ or the like.
In addition, you may employ | adopt what mixed the nucleus 46a which is not covered with the coating film 46b in the said composite_body | complex as a CO production | generation inhibition part.

  Therefore, in the surge protection element 41 of the fourth embodiment, the CO generation inhibiting portion 46 includes a core portion 46a made of the element that easily binds to oxygen and a coating that is formed of an insulating material and covers the core portion 46a. Since the core portion 46a is protected by the coating film 46b, the sublimation disappearance of the core portion 46a due to discharge can be suppressed, and the CO production inhibition mechanism can be maintained. it can. Note that at least part of the coating film 46b disappears due to arc discharge, so that the core 46a is exposed and oxygen can be absorbed.

  The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, as in the second embodiment, it is preferable to form the CO generation inhibiting portion 26 in each of the pair of electrode facing regions A1, but as another example, as shown in FIG. 7, the pair of electrode facing regions A1 Of these, the surge protection element 51 in which the CO generation inhibiting portion 26 is formed only on one side may be used.

  1, 21, 31, 41, 51 ... surge protection element, 2 ... insulating tube, 3 ... sealing electrode, 4 ... discharge auxiliary part, 5 ... protruding electrode part, 6A, 6B, 26, 36, 46 ... CO generation Inhibition part, 46a ... core part, 46b ... coating film

Claims (4)

An insulating tube;
A pair of sealing electrodes for closing the opening at both ends of the insulating tube and sealing the discharge control gas inside;
A discharge auxiliary portion formed of a carbon material on the inner peripheral surface of the insulating tube;
The pair of sealing electrodes has a pair of protruding electrode portions protruding inward and facing each other,
A surge protection element characterized in that a CO generation inhibiting portion containing an element that is more easily bonded to oxygen than carbon is formed on the inner peripheral surface of the insulating tube. The surge protection element according to claim 1,
The surge protection element, wherein the CO generation inhibiting portion is formed in the vicinity of the discharge assisting portion. The surge protection element according to claim 1 or 2,
The surge protection element, wherein the CO generation inhibiting portion is formed in an annular shape extending over the entire circumference of the inner peripheral surface of the insulating tube. In the surge protection element according to any one of claims 1 to 3,
Surge protection characterized in that the CO production inhibiting part is composed of a core part made of the element that is easily bonded to oxygen and a coating film that is made of an insulating material and covers the core part. element.

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