JPS5843848B2 - Fuse element and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuse element used to protect an electrical system, and in particular to an improvement of a fuse element in which a metal with excellent conductivity is filled with a fluorine compound with excellent interrupting properties.

Current-limiting fuses used to protect high-voltage electrical systems have a current range in which it is difficult to shut off, from the minimum fusing current to several times the rated current.

In order to improve the blocking performance in the small current range, the inventor created a gaseous body of fluorine compound with excellent blocking properties by thermal decomposition after melting in a chemically stable metal with excellent conductivity such as Ag. We previously proposed a fuse element filled with a fluorine compound such as AlF3, which has excellent interrupting properties (Japanese Patent Application No. 67431).

A current-limiting fuse using this fuse element is capable of breaking in a small current range several times the rated current, which could not be broken with conventional current-limiting fuses using Ag as an element and silica sand as an arc-quenching agent. Many results were obtained, including achieving the objectives mentioned above.

However, the fuse element that the inventor proposed earlier,
When heated for a long time at temperatures exceeding 600°C, there is a phenomenon in which the electrical resistance gradually increases, and this does not cause any particular problems when used as a protection fuse for general electrical systems.
For example, when used in electrical systems such as electric furnaces that are frequently turned on and off, the temperature of the fuse element tends to rise due to overload current, which tends to cause deterioration of the fuse. was there.

This invention is based on the electrical resistance that occurs when a fuse element, which was previously proposed by the inventor and is made of a highly conductive metal filled with a fluorine compound with excellent interrupting properties, is heated to a temperature exceeding 600°C for a long period of time. By suppressing the increase in
It is an object of the present invention to enable the use of an element having the same effect as the fuse element previously proposed by the above-mentioned inventor for the protection fuse of an electrical system where the element is likely to cause a rise in temperature.

The specific structure of the fuse element of this invention is Ag
In a metal with excellent conductivity filled with a fluorine compound having excellent interrupting properties such as AlF3, a partition wall is placed between the metal with excellent conductivity and the fluorine compound to prevent direct contact between the metal and the fluorine compound. It has been established.

Examples of metals with excellent conductivity used in the fuse element of this invention include Ag, A7, A, and utC.
ct.

Cu, Pb, Sn, Zn, and alloys based on these metals are suitable, and in addition to these metals, a wide variety of highly conductive metals used in fuses are available.

In addition, as the fluorine compound with excellent interrupting properties to be filled into the metal with excellent conductivity in this invention, AlF
3. CaF3. CF2CF2. ZrF4 or the like can be used.

Furthermore, as a material constituting the barrier wall separating the highly conductive metal and the fluorine compound, Al2O3t B
Chemically and thermally stable oxides such as eOj CaOt MgO, 5t025 'rho2, or compounds or mixtures containing these oxides as a main component, and natural compounds containing the above oxides as a main component and trace amounts of other impurity elements. In addition to these, glass powders such as soda glass, lead glass, and silicate glass, and powders of organic compounds with excellent heat resistance such as silicone resin and fluororesin can also be used. Can be used widely.

The structure of the fuse element of this invention is shown in Fig. 1a and b.
As shown in the wire element shown in FIG. 2 and the ribbon element shown in FIG. 3.

The improvement in heat deterioration resistance exhibited when the fuse element of the present invention having the above-described structure is heated at high temperature for a long time is shown in Table 1 below.

That is, in a device using Ag as a metal with excellent conductivity, AlF3 as a fluorine compound, and Al2O3 as a partition wall constituent material, the temperature at which the electrical resistance value increases by 10% compared to the electrical resistance value before heating after 500 hours of heating is determined. In comparison, the temperature was 600°C in the case without partition walls, whereas the temperature was improved to 900°C in the fuselage elements 1 to 1 of this invention.

Further, the fuse element of the present invention can be easily manufactured by the following manufacturing method.

That is, powders of refractories, glass, heat-resistant resins, etc. are stirred and mixed with a binder and a solvent such as water, alcohol, etc.
Make a paste-like bulkhead material.

As the binder, kaolin, dextrin, polyvinyl alcohol, sodium silicate, and various other adhesive resins can be widely used.

Next, a tube made of a highly conductive metal prepared in advance is immersed in the barrier rib material and then taken out, the barrier rib material adhering to the outer surface of the tube is wiped off, the tube is heated and dried, and if necessary, the barrier rib material is By repeating this application, a partition wall of a predetermined thickness is formed on the inner wall of the conductive metal tube.

After that, the conductive metal tube with partition walls formed on its inner wall is filled with a fluorine compound powder with excellent barrier properties while being vibrated, and then processed through processes such as swaging, extrusion, wire drawing, and rolling, as well as an annealing process, to achieve the necessary results. Manufacture fuse elements of different sizes and shapes.

As explained above, the fuse element of the present invention, in which a fluorine compound with excellent interrupting properties is filled into a highly conductive metal through a partition wall, is capable of filling a fluorine compound into a conductive metal without providing a partition wall. The heat deterioration resistance is improved compared to a fuse element filled with Fuse, making it possible to use it as a protective fuse for electrical systems that are frequently opened and closed.

In addition, a current limiting fuse in which the fuse element of the present invention is installed in the fuse cylinder together with an arc extinguishing agent such as silica sand has an excellent cooling deionization effect based on the melting and vaporization of fluorine compounds in the fuse element. Demonstrates blocking properties.

Furthermore, in the fuse element of the present invention in which a fluorine compound is filled in a highly conductive metal through a partition wall, the fuse element may be After being installed in the fuse cylinder together with an arc agent, the glass, resin, etc., are heated by means such as electrical heating that does not cause the fuse element to melt at a temperature higher than the softening temperature of the glass, resin, etc. that constitutes the partition wall. The fluorine compound, which is the core material, is sealed by softening and melting the partition wall material,
Separation between the conductive metal and the fluorine compound can be ensured.

[Brief explanation of the drawing]

1A and 1B are a side sectional view and a cross-sectional view showing one embodiment of the present invention, and FIGS. 2A and 2B are a side sectional view and a cross-sectional view showing another embodiment of the invention. 1: Metal with excellent conductivity, 2: Partition wall, 3: Fluorine compound. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. In a fuse element in which a fluorine compound with excellent interrupting properties is filled in a metal with excellent conductivity, direct contact between the metal with excellent conductivity and the fluorine compound is prevented. A fuse element characterized by having a partition wall. 2 Ag, Al, and Au as metals with excellent conductivity. The fuse element according to claim 1, characterized in that Cu, Cd, Pb, Sn, Zn, and alloys based on these metals are used. 3 AlF3°C as a fluorine compound with excellent blocking properties
aF2. CF2=CF2. The fuse element according to claim 1, characterized in that a powder such as ZrF4 is used. 4 A1203, BeO2 as substances constituting the partition wall
A patent claim characterized in that one type or a mixture of two or more types of thermally stable oxides such as CaO2MgO2SiO2, ThO2, ZrO2, etc., or a naturally occurring refractory containing the above oxides as a main component is used. Fuse element as described in Range 1. 5. The fuse element according to claim 1, characterized in that one or more types of glass powders such as soda glass, lead glass, and silicate glass are used as materials constituting the partition walls. 6. The fuse element according to claim 1, wherein an acidic compound having a high melting point, such as a fluororesin or a silicone resin, is used as the material constituting the partition wall. 7. Place the material constituting the partition wall in contact with the inner wall of a tube made of highly conductive metal, then fill the center with fluorine compound powder with excellent blocking properties, and if necessary, compression mold or heat treatment. A process for producing a fuse element, which is characterized in that the fuse element is formed by forming the wire, followed by processing such as drawing, wire drawing, and rolling, and if necessary, softening annealing.