JPS60172122A - Self-recovery type current limiting element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a self-healing forming flow element,
To be more specific, when an overcurrent flows, the current limiting material vaporizes and becomes high resistance, limiting the overcurrent. When the overcurrent disappears, the current limiting material self-recovers, liquefies or solidifies, and passes a steady current. The present invention relates to self-healing formation flow elements.

[Prior art]

A conventional current limiting element of this type is shown in FIG.

In the figure, the first electrode is formed by processing a conductive metal, such as chromium copper, and has a long hole passing through it along the center line. A sealing needle pulp V made of a sodium-resistant metal such as stainless steel is screwed into the screw hole 3 at the upper end of this elongated hole. A screw 5 is provided on the outer periphery of the upper end of the first electrode l, which protrudes to the outside, and can be used for attaching a terminal. The other end of the first electrode l is an insulating tube 6
, 7. The intermediate spacer g faces the first electrode IO made of stainless steel via the insulating sleeve spacer. The intermediate spacer g and the insulating tube support spacer are made of a sodium-resistant metal such as steel, which can connect the insulating tube 6.7 and seal the connection surface. On the center line of the first electrode /θ, an inner circumferential screw hole 12 passes through the hole l, and the piston terminal /3
are screwed together, and the first electrode lθ and the piston terminal 13
It is sealed with a seal ring/U. On the center line of the piston terminal 13 are a large diameter hole /j, a small diameter hole 16, and a screw hole 1.
7 is penetrated, and a piston lt made of a sodium-resistant metal such as stainless steel is set in a position where it can slide along the large diameter hole 13 via the O-ring/9. The small diameter hole 16 is hermetically sealed by screwing a 21 dollar valve head 0 made of stainless steel or the like into the screw hole 7. The insulating cylinders 6.7 are hollow pipe-shaped having through holes AK and 7a of different diameters, and are made of a heat-resistant and alkali-resistant insulating material with good thermal conductivity, such as beryllia porcelain or alumina porcelain. .

The insulator 21 firmly connects the insulating tube, the intermediate spacer t, the first electrode l, and the second electrode IO. The insulator 2/ is made of, for example, glass or mica plastic, which is obtained by firing a mixed powder of mica powder and glass powder to a temperature at which the glass powder softens and flows. Second electrode/
, 10. Heating the insulating cylinder 6°7, the intermediate spacer S and the insulating cylinder support spacer 9 to a temperature above which the glass softens and flows,
The above-mentioned parts are fixed by inserting the mold into a preheated room and performing hot pressure molding using a molding press. The first electrode 10 is made of a metal with strong mechanical strength, such as stainless steel.

The current limiting material has a long hole, a through hole Aa of the insulating cylinders 6 and 7,
? a, the space from the hole l/ to the large diameter hole 15 of the piston terminal 13 is filled; for example, the nut has a small hole on its center line so that it can be filled with a current limiting material. An outer circumferential screw λ6 protrudes from the outer end of the piston terminal/3, allowing the terminal to be attached.

When an overcurrent flows through the current limiting element configured as described above, first, the current limiting material in the through hole 6a with a small cross-sectional area of the current limiting material 2λ is vaporized, and then the current limiting material λ is sequentially vaporized, and the plasma This creates a high resistance and limits the overcurrent below a certain value. The reduced vapor pressure generated during vaporization acts in the axial direction, causing the movable piston/I to move and compressing the back pressure gas 23, which is a pressure buffer. On the other hand, this vapor pressure is further applied to the inside of the elongated hole of the first electrode l. The inner circumferential screw of 2 is applied to the stepped portion 2ja of the setscrew 2S screwed into the 2nd part. The other is the pressure that acts in the radial direction, and the through holes 6a of the insulating cylinders 6 and 7. A high pressure is applied to the first electrode l OK from the inner wall of a through the insulator l. The high pressure generated inside the current limiting element as described above is alleviated in the axial direction by the piston lt using the back pressure gas 23, and furthermore, the strength is exerted by the material composition of the second electrode io and the insulator 21. Ru. In other words, in terms of material composition, the coefficient of thermal expansion of the insulating cylinder 9 located at the center is smaller than that of the insulator 21 (the coefficient of thermal expansion of the insulating cylinder 6 to Ir×lθ-'/C and the insulator 1
0"'-/koxlO'/'C), and the coefficient of thermal expansion of the insulator 21 is smaller than that of the stainless steel of the first electrode 10 (insulator 10-/kox10-'7°C and stainless steel/ 6×l
The material is composed of a material having a temperature of O-&/℃), and compressive force is applied in the radial direction from the second electrode IO on the outer periphery toward the center at a temperature below the temperature at which the glassy fluidity of the insulator loses and hardens during molding. . Similarly, in the axial direction, the second electrode 1
The insulating cylinder 6.7 is inserted from the step part /11 of the first electrode through the bottom surface part 9eL of the insulating cylinder receiving spacer 9 and the set screw 3 and insulator l provided at the opposite end thereof. , intermediate spacer t
The structure maintains the sealing properties of each part and the internally generated pressure by applying compressive stress to the structure.

During current limiting, the first electrode l, the second electrode 10 and the piston/
Although a circuit voltage is applied between the terminal 13 and the terminal 13, insulation against this voltage is provided by an insulator 1. After the overcurrent is limited by this current limiting element, it is cut off by a switch (not shown) provided in series.

Thereafter, the current limiting material 22 is cooled and liquefied or solidified by the back pressure gas 2J, which is a pressure buffer, to restore the normal state.

In the above operation, when a steady current is flowing, the current limiting material 22 generates Joule heat, which is heated to a temperature of .degree.

Most of this Joule heat is absorbed by the insulating cylinder 6. through hole Aa
,? This is due to the two current limiting materials filled in a, and this Joule heat is absorbed by the first electrode l or the insulating cylinder spacer? Heat is radiated by axial heat conduction through the second electrode IO and radial heat conduction through the insulating cylinders 6, 7, the insulator IO, and the first electrode 10, resulting in an equilibrium state. The current flow is determined from the temperature rise limit at this time. Particularly, the portion of the through hole 6a of the two current limiting materials having a small cross-sectional area generates a large amount of heat.

However, in the conventional device mentioned above, heat radiation in the radial direction is limited to the insulator 2.
1 and the stainless steel of the first electrode 10 have poor thermal conductivity, which has the disadvantage that a large current cannot flow through them.

[Summary of the invention]

This invention was made in view of the above-mentioned circumstances, and a second electrode is disposed on the outer periphery of the insulating tube through an inorganic insulating material, thereby making it possible to improve the The present invention provides a self-recovery forming current element capable of passing a large current.

[Embodiments of the invention]

In FIG. 2, the lower end of the first electrode l and the insulating cylinder 6.7
, an insulating cylindrical spacer 109 with a bottom surrounds the intermediate spacer zone.
is installed. This insulating cylindrical spacer lθ is made of copper or a copper alloy such as chrome-copper, and is inserted in advance into the inner peripheral portion of the second electrode /10. That is, the first electrode/
The inner diameter of lθ is made slightly smaller than the outer diameter of the insulating cylinder/(7?).

Then, the first electrode 110 is heated and the insulating cylinder spacer 109
The inner peripheral surface of the first electrode/10 and the outer peripheral surface of the insulating cylindrical spacer 109 are brought into close contact with each other by inserting and fitting them at a lower temperature using a crooked fit method. The first electrode /10 subjected to this processing has an inner circumferential screw hole extending therethrough, into which the piston terminal /J is screwed. Insulating tube spacer IO'i
A circumferential seal ring groove is provided at the end of the seal ring, and the seal ring is hermetically sealed by the seal ring/llK. Piston terminal 13
On the center line of is the piston/g, 0
The ring/9 is assembled and the back pressure gasket 3 is sealed by the needle pulp 20 at the end of the pore 16.

It is conceivable that the first electrode/10 is formed at least partially of chromium copper in consideration of heat dissipation.

Other parts that are the same as those in FIG. 1 are denoted by the same reference numerals, and explanations thereof will be omitted.

Next, the operation will be explained. When an overcurrent flows through the current limiting element configured as above, the two current limiting materials vaporize as in the one in Figure 1, creating high pressure inside, and the piston it moves to buffer the pressure. But still xooo~5oo
o atmospheric pressure. At this pressure, the current limiting element has a strength that will not be destroyed by the insulator 21, the outer cylindrical part of the first electrode/10 having strong mechanical strength, and the insulating cylindrical spacer ioq located on the inner periphery of this outer cylindrical part. There is. After the overcurrent is cut off, the back pressure gas control unit J
The current limiting material is restored to its original state by VC.

When a steady current is flowing through this current limiting element, the current limiting interest is 2
Since the Joule heat generated in the through hole 6a accounts for 3O-fO% of the total amount of heat generated in the through hole 6a, the part located in the insulating cylinder 6 of the insulating cylinder spacer ioq, which has good thermal conductivity and is made of copper or copper alloy, Heat is conducted and dissipated more in the axial direction. Further, the insulating cylinder spacer lθde is directly tightly sealed with the piston terminal /3, and Joule heat is dissipated by heat conduction in the axial direction. Furthermore, heat dissipation from the insulating cylindrical spacer 109 to the outer periphery of the first electrode tio is also effective in the radial direction. Therefore, if the current is the same as in the past, the temperature of the current limiting material will be lower and the amount of heat generated will be lower.

On the other hand, if the temperature rise of the two current limiting materials is kept the same as the conventional one, the current flowing can be increased.

〔Effect of the invention〕

As described above, the present invention provides the first electrode with mechanical strength during current-limiting operation, uses copper or copper alloy with good thermal conductivity for the insulating tube spacer, and connects it directly to the piston terminal. It is possible to increase the current flowing without changing the diameter of the through hole of the cylinder, and there is an effect that the current carrying capacity can be increased.

[Brief explanation of the drawing]

FIG. 7 is a vertical cross-sectional view of a conventional device, and FIG. 2 is a vertical cross-sectional view of an embodiment of the present invention. In the figure, / is the first electrode, C is a long hole, 3 is a screw hole, Hiro is needle pulp, S is a peripheral screw, 6.7 is an insulating cylinder, Aa
,? a is a through hole, S is an intermediate spacer, // is a hole, 12 is an inner peripheral screw hole, 13 is a piston terminal, /! is a large diameter hole, 16
is small diameter hole, it is piston, / is 0 ring, -〇 is needle pulp, ,;! / is an insulator, a, 2 is a current limiting material, 23 is a back pressure gas, 2S is a set screw, roller is an outer peripheral screw,
109 is an insulating cylindrical spacer, and /10 is a first electrode. In each figure, the same reference numerals indicate the same or corresponding parts. 1935 1937 677th, Mr. Commissioner of the Japan Patent Office 1, Indication of the case Showa! The year patent application No. JJL? f No. 2, title of the invention Self-V old type current limiting element 6, the description of the amendments is amended as follows.

Claims (1)

[Scope of Claims] (1) A first electrode and the first electrode via a cylindrical insulator.
a first electrode disposed coaxially with the first electrode surrounding the first electrode; and a pair of l pairs having different diameters disposed within the insulator between the first electrode and the first electrode. an insulating tube in which a through hole is formed; a piston terminal connected to the first electrode and in communication with the through hole and in which a hole is formed for accommodating the piston; 1.
In a self-restoring forming flow element comprising a current limiting material conducting through a first electrode and a back pressure gas filled in the back of the piston, the A self-restoring forming flow element comprising an insulating cylindrical spacer made of a metal with high thermal conductivity and interposed between the second electrode and the second electrode. (3) A self-healing forming flow element according to claim 1, which includes an insulating cylindrical spacer made of a metal selected from copper and a copper alloy. (3) A patent claim, which includes an insulator made of glass or mica plastic. The self-restoring forming flow device according to claim 7. (II) The self-restoring forming flow device according to claim 1, comprising a second electrode at least partially made of chromium copper.