EP0098308B1 - Commutateur - Google Patents

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Publication number
EP0098308B1
EP0098308B1 EP83900281A EP83900281A EP0098308B1 EP 0098308 B1 EP0098308 B1 EP 0098308B1 EP 83900281 A EP83900281 A EP 83900281A EP 83900281 A EP83900281 A EP 83900281A EP 0098308 B1 EP0098308 B1 EP 0098308B1
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EP
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Prior art keywords
light
inorganic
materials
fibrous
porous
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EP83900281A
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German (de)
English (en)
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EP0098308A4 (fr
EP0098308A1 (fr
Inventor
Yoshiaki Mitsubishi Denki K.K. Sakamoto
Hajimu Mitsubishi Denki K.K. Yoshiyasu
Yuichi Mitsubishi Denki K.K. Wada
Shiro Mitsubishi Denki K.K. Murata
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Priority claimed from JP562682A external-priority patent/JPS58121524A/ja
Priority claimed from JP6441882A external-priority patent/JPS58181248A/ja
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Publication of EP0098308A1 publication Critical patent/EP0098308A1/fr
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
    • H01H9/30—Means for extinguishing or preventing arc between current-carrying parts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H73/00—Protective overload circuit-breaking switches in which excess current opens the contacts by automatic release of mechanical energy stored by previous operation of a hand reset mechanism
    • H01H73/02—Details
    • H01H73/18—Means for extinguishing or suppressing arc

Definitions

  • switch relates to the suppression of pressure in a housing of a switch.
  • switch indicates what generates an electric arc in the housing and usually the small-sized housing of a circuit interrupter, a current limiting device, an electromagnetic switch etc.
  • Figures 1 through 3 are sectional views showing a prior art circuit interrupter and illustrating the different operating states respectively.
  • (1) is a cover, and (2) is a base.
  • the cover (1) and base (2) constitute a housing (3).
  • (4) is a stationary contactor having a stationary conductor (5) which has a stationary contact (6) provided at its one end, and the other end thereof is formed into a terminal unit so as to be connected to an external conductor (not shown).
  • (7) is a movable contactor having a movable conductor (8) which has at one end a movable contact (9) opposing to the stationary contact (6).
  • (10) is a movable contactor assembly, and (11) is a movable contact arm fixed to a cross bar (12) with each pole arranged to be simultaneously opened and closed.
  • (13) is an arc extinguishing compartment in which arc extinguishing plates (14) are supported by a lateral plate (15).
  • (16) is a toggle linkage which is composed of an upper link (17) and a lower link (18). One end of the upper link (17) and the other end thereof are connected to a cradle (19) and to one end of the lower link (18) by means of shafts (20) and (21) respectively. The other end of the lower link (18) is further connected to the movable contact arm (11) of the movable contact assembly (10).
  • (22) is a turntable operating handle, and (23) is an operating spring spanned between the shaft (21) of the toggle linkage (16) and the operating handle (22).
  • (24) and (25) are respectively a thermal and an electro-magnetic trip mechanism. In operation, they are arranged to rotate a trip bar (28) in a counterclockwise direction by a bimetal element (26) and a movable iron core (27) respectively.
  • (29) is a latch which has one end engaging the trip bar (28) and the other end engaging a cradle (19). With the cradle 19 engaged by the latch (29), and when the operating handle (22) is turned to a closed position, the toggle linkage (16) is stretched to engage shaft (21) with the cradle (19) and to connect the movable contact (9) to the stationary contact (6). This state is shown in Figure 1.
  • That arc voltage is raised in proportion to an increase in separation of the movable contact (9) from the stationary contact (6), and further raised because the electric arc (32) is simultaneously attracted towards the arc extinguishing plates (14) by means of a magnetic force.
  • an arc current reaches zero thereby extinguishing the electric arc, resulting in the completion of an interruption.
  • That injected enormous arc energy is eventually put in the form of heat energy and completely escapes to the outside of the housing.
  • a temperature of a gas within the limited housing is transiently raised which, in turn, results in a sudden rise of a gas pressure.
  • FIG 4 is a view showing an electric arc A generated between the contactors (4) and (7).
  • T indicates a stream of heat energy escaping from the electric arc by conduction through the contactors
  • m indicates a stream of energy of metal particles escaping from an arc space
  • R indicates a stream of energy due to light escaping from the arc space.
  • energy injected into the electric arc is mostly consumed by the three energy streams T, m and R as described above. Among them, the heat energy T escaping to the electrode is very slight, and a major proportion of energy is carried away by the streams m and R.
  • the energy R in the Figure has been previously almost ignored while the energy m is overwhelming. From recent researches conducted by the inventors, however, it has been found that the energy R, that is, the consumption of energy due to the emission of light, can reach approximately 70% of the energy injected into the electric arc.
  • Figure 5 shows an electric arc which is confined in a housing.
  • the confinement of the electric arc in the housing results in a situation in which a space in the housing is filled with an electrode metal at a high temperature. This situation is particularly pronounced in a gas space Q surrounding the positive column A of the electric arc (the space Q being shown hatched in the Figure).
  • Light originating from the electric arc is emitted from the positive column A thereof to irradiate and be reflected from the walls of the housing (3). Reflected light is scattered to and passes again through the high temperature space filled with electrode particles and again irradiates the walls. Such a process is repeated until the amount of light becomes zero.
  • the path of light in this process is indicated by RA-Rb-Rc-Rd in the Figure.
  • the consumption of light originating from the electric arc is by the following:
  • an amount of light absorbed by the gas space can be calculated as follows:
  • the expression (1) represents a quantity of absorbed energy for a specific wavelength X.
  • A is the probability A of absorption for the specific wavelength X, and is a function of the wavelength X, the temperature of the gas, and the kind of particles.
  • the absorption coefficient A has the greatest value with a gas which is in the same state as a light source gas emitting light (that is, having the same kind of particles and temperature) for continuous and line spectra. That is, light originating from the arc space is most absorbed by the arc space and surrounding gas space.
  • the quantity l a of absorbed energy of light is proportional to the length L of the optical path.
  • L in the expression (1) is increased by a number of reflections thereof resulting in an increase in quantity of light energy absorbed by a high temperature portion of the arc space.
  • an arc chamber for use in electric switch gear, has side walls consisting of perforated slabs. lonised gases can pass through these walls and are thus cooled and de-ionised. These walls make it possible for processes on both sides of the arc to be equalized.
  • This patent is concerned with pressure equalization in larger circuit breakers, and achieves this by wedge-shaped disposition of the slabs.
  • EP-A-0092189 describes a circuit breaker with light absorbing means incorporated, made of a composite material of fiber or porous material having. more than 35% of apparent porosity. This document has partly the same priority date as the present application.
  • the present invention provides a switch comprising at least a pair of contactors composed of conductors and contacts fixed thereto, and performing the opening and closing operations, a housing for accommodating said contactors, and an optical absorber disposed at a position where it receives light energy of light from an electric arc occurring upon said contactors performing the opening operations, said optical absorbers being formed of at least one or'more of the kinds of inorganic high porous materials having the apparent porosity of not less than 35% of inorganic fibrous system materials and porous blanks.
  • said optical absorber effectively absorbs light energy, the light energy occupying a greater part of the consumption of energy injected into an electric arc, to reduce the temperature of a gas space in the housing of the switch thereby to reduce pressure within the housing of the switch.
  • an inorganic fibrous system material having a percentage of voids of not less than 40% of a fibrous blank or an inorganic high porous material having an apparent porosity of from 40 to 70% of a porous blank, then light energy generated from an electric arc can be more effectively absorbed, and the pressure within the housing of the switch can be reduced.
  • porous material easily releases powders, this release of the powders can be prevented by using a porous material having a high surface density.
  • Figures 1 through 3 are sectional views of a conventional circuit interrupter and illustrate the different operating states respectively;
  • Figure 4 is an explanatory view showing a manner in which an electric arc is generated between contacts:
  • Figure 5 is an explanatory view showing a manner in which an electric arc is generated between contacts in a housing;
  • Figure 6 is a perspective view showing an inorganic high porous blank;
  • Figure 7 is a fragmentary enlarged sectional view of Figure 6;
  • Figure 8 is a diagram of curves showing changes in pressure in a housing with various inorganic high porous materials of different apparent porosity, upon the generation of an electric arc;
  • Figure 9 is a perspective view of a fibrous system blank;
  • Figure 10 is a fragmental enlarged sectional view of Figure 9;
  • Figure 11 is another embodiment of the present invention and a sectional view of a circuit interrupter using an inorganic high porous material as an optical absorber;
  • Figures 12 to 16 show another embodiment of the present invention, wherein Figure 12 is a
  • Porous blanks are generally materials having a multitude of pores in the solid structure and exist in materials of many types including metals, inorganic systems, organic materials etc. The relationship between the type of the material and the pores distinguishes one material from another. On the one hand materials may have been sintered and solidified at points where solid particles are contacted by one another, and on the other hand materials may have holes as the main constituent, the material being formed of portions which are of a solid material. Further the word "blank”, referred to in the present invention refers to a raw material before any shaping process is carried out.
  • the materials can be divided into, among others: those having gaps between particles, the gaps existing as pores; and those having jointly gaps between particles and pores in holes within the particles, these including foamed holes in the interior thereof. Also they may be roughly divided into those having a gas and a water permeability, and those which include independent or separate pores therein and which do not have a gas permeability.
  • the shape of said pores is very complicated and can be broadly classified into an open pore and a closed pore.
  • the structure of a material is indicated by a pore volume or a porosity, a pore diameter and a distribution of pore diameters over a specific surface area etc.
  • the true porosity of a material is indicated by the proportion of the volume of all pores, and open and closed holes in a porous blank of the material to the total volume (a bulk volume) of the blank.
  • the true porosity may be expressed as a percentage.
  • a measurement method depends upon a substitution and an absorption method based on a liquid or a gas, but a simple and easy way (as defined by a method of measuring a specific weight and porosity of a fire-resistant brick according to JIS R2614), of calculating it is as follows:
  • An apparent porosity indicates a proportion of the volumes of open holes alone in relation to the total volume (a bulk volume) of the blank, this may be expressed as a percentage and, is defined by a method of measuring an apparent porosity, an absorption factor and a specific weight of a fire-resistant brick according to JIS R 2205.
  • the apparent porosity is calculated as follows: the apparent porosity is also called an effective porosity.
  • the pore diameter is obtained from measured values of pore volumes and the specific surface area.
  • the pore diameters range from what approximates to the size of an atom or an ion to a boundary gap of a particle cluster. Hence, the pore diameters range from a few tenths of nanometres or angstrom units to a few millimeters. However it is generally defined by the mean value of the distribution thereof.
  • the shape and size of the pores and the distribution thereof can be measured by a method based on a microscope or a mercury intrusion method.
  • the use of the microscope is desirable because of the direct observation.
  • the BET method In the measurement of the specific surface area, the BET method is in many cases, used. This method utilizes absorption isothermal lines of various absorbed gas matters at each temperature, and a nitrogen gas is frequently used.
  • Figure 6 is a perspective view showing an inorganic high porous blank and Figure 7 is a fragmentary enlarged sectional view of Figure 6.
  • (33) designates the inorganic high porous blank
  • (34) designates an open pore communicating with the surface of the inorganic matter.
  • the pore diameter, of the open pore (34) indicates various distributions including large and small sizes ranging from a few microns to a few millimeters.
  • Figure 8 is a graph showing the change in pressure which occurs due to an electric arc within a modelled housing, into which various inorganic high porous materials have been selectively disposed, for various inorganic high porous material of differing apparent porosity.
  • the abscissa axis represents the apparent porosity and the ordinate axis is normalized with respect to the pressure in the case where the electric arc occurs in a housing in which the inner wall is formed of a metal such as Cu, Fe, AI or the like.
  • the experimental conditions were adopted: AgW contacts were disposed at a constant gap of 10 mm within the enclosed housing of a cube having one side of 10 cm; and an electric arc, with a sinusoidal wave having the peak of 10 KA, was generated for 8 milliseconds to measure a pressure within the housing caused by energy at that time.
  • An inorganic high porous material was formed from a raw pottery material of a cordierite matter.
  • the matter was molded by a method which involved adding an inflammable or a foaming agent thereto and sintering the product into porous potteries thereby rendered highly porous.
  • a change in pressure at that time is shown at curve a in Figure 8.
  • Alternative inorganic high porous materials comprising insulating fire bricks of an alumina matter having mean pore diameters ranging from 50 to 11 pm, and apparent porosities of 30, 40, 50, 60 and 65% respectively, were machined to form high porous blanks of 4 mm (thickness of 4 mm). They were disposed on the wall surface of the housings so as to cover 50% of the surface area of the inner surface of the housings. A change in pressure at that time is shown at curve b in Figure 8.
  • Inorganic high porous materials of Na 2 0-B 2 O 3 -SiO 2 system Vycor glasses with through pores having: a) a pore diameter of 100 to 200 pm, and an apparent porosity of 30%; b) a pore diameter of from 20 to 30 ⁇ m, and an apparent porosity of 40%; c) a pore diameter of 50 to 300 ⁇ m, and an apparent porosity of 60%; and d) a pore diameter of 50 to 300 pm, and an apparent porosity of 70% respectively were used with 4 mm. They were disposed on the wall surface of the housings so as to cover 50% of the surface area of the inner surface of the housings.
  • Gypsums were used as the inorganic high porous materials.
  • the gypsums were cement cured member, and had a pore diameter of not larger than 30 pm and apparent porosities of 45%, 50 and 60% respectively. These were used with 4 mm and similarly disposed on the wall surface of the housings so as to cover 50% of the surface area of the inner surface of the housings. A change in pressure at that time is shown at curve d Figure 8.
  • the pores in the inorganic high porous material absorb light energy to exhibit the effect that a pressure in the interior of the switch decreases and this is enhanced with an increase in apparent porosity of the inorganic porous blank.
  • the effect is particularly noticeable with the apparent porosities of not less than 35% and has been confirmed in a range up to 85%. If the porosity is further increased then a countermeasure is required, namely increasing the thickness of the high porous material.
  • the apparent porosity of 30% is effective because the glass itself permits light to penetrate therethrough and has a relatively large specific surface area so that it is easy to absorb energy of light through a boundary surface thereof and the effect is large even with materials having a small porosity.
  • the porous blanks having increased apparent porosity become brittle, decrease in thermal conductivity and are more easily melted by heat. Also in the case of a small apparent porosity the effect of decreasing the pressure within switches is scanty. Accordingly the high porous materials are optimum with the apparent porosity of the high porous blanks ranging from 40 to 70% for practical purposes.
  • the characteristic tendency is applicable to general inorganic porous materials which can be conjectured from the foregoing description concerning the absorption of light.
  • the mean pore diameter As to the pore diameter, light absorption is increased if the mean pore diameter somewhat exceeds a region of wavelengths of light, depending upon the proportion of these pores occupying the surface, that is to say, an amount of the specific surface area of these pores. Also for the absorption of light within the pore, materials having deep pores are effective and communicating pores are desirable. Since light emitted from an electric arc in a switch is distributed between a few tens of nanometres (a few hundred angstrom units) and 1 ⁇ m (10,000 A), then a mean pore diameter somewhat exceeding this, that is, a mean pore diameter of a few hundred nanometres (a few thousand angstrom units) to a few thousand ⁇ m is suitable.
  • High porous materials having the area of the pores occupying the surface to be equal to or larger than the apparent porosity of 35% are suitable for absorbing light emitted from the electric arc.
  • inorganic materials may be used with conventional switches, the purpose of their use is mainly to protect housings against the electric arc and the characteristics thereof require the arc resistance, lifetime, thermal conductivity, mechanical strength insulation and countermeasure to carbonization.
  • the inorganic materials fulfilling them are necessarily intended to be dense and consequently serve a different function.
  • the apparent porosity thereof is of about 20%.
  • High porous blanks may be of inorganic, metallic and organic systems etc.
  • An inorganic system is characterized by the insulating material and high melting points. Those two properties are suitable for materials disposed within the housing of switches. Since they are electrically insulating materials, they do not seriously affect the interruption and are also optimum as pressure suppressing materials because, even when exposed to hot heat, they do not melt or evolve a gas or gases.
  • this inorganic system there is involved and used what includes an inorganic material as the principal constituent and an organic material as a binder or the like.
  • Porous materials of the organic system encounter problems owing to the heat resistance and the generation of a gas or gases and those of the metallic system are problematic due to the electrical insulation and the pressure resistance. Thus the organic and metallic systems are limited as to the position where they can be disposed.
  • porous materials other than those given in the examples, such as pottery particles, which are uniform in particle diameter, for example: metal oxides or alumina, silica, zircon, magnesia and zirconia; powder of special pottery materials such as mullite, forstelite, steatite, lithia, spinel etc.
  • porous pottery materials of calcic, hard, clayish, silicic and dolomitic materials prepared by mixing and sintering a raw clayish materials with quartz, pottery stone, limestone, dolomite and a small amount of feldspar, and unglazed earthenwares and others prepared by firing raw clayish materials as the principal component at low temperatures.
  • porous refractory materials there may be used, as insulating fire bricks, magnesia, zirconia, cordierite, silicon carbide, vermiculite, and chromium magnesia materials in which pores are formed by .
  • alumina materials, pearlite and vermiculate materials these are by firing, and in the case of vermiculite diatomaceous earth matter etc, these are foamed using an artificial forming agent such as alumina or zirconia bubbling agent or a natural pore forming agent such as diatomaceous earth.
  • a heat generating material having carbon silicate as the principal component, a grind stone quality and others may be applied.
  • porous glasses there may be also used, in addition to the Example, sintering a high silicate glass powder, foam glasses and others prepared by firing mixtures of glass powders and foaming agents by utilizing transmission to light.
  • porous cured cement materials cured cement materials themselves, such as concretes, mortars, slates etc. generally used with civil engineering works or as building materials having porosities and may be used. With regard to high porous materials however, a factor which increases the number of pores is mixing and curing a cement slurry with small pieces of inflammable wood or a powdered resinous material followed by sintering is preferable. Heater plates (ie thermal insulator plates or heat resistant plates used in electric heaters or the like), and light weight concretes or a cement slurry, caused to include a multitude of air bubbles and cured like a porous cement, is also preferable.
  • fibrous blanks are as follows.
  • the fibrous blank is composed of an aggregate of fibers or a combination of fibers and a surface treating agent or a binder and includes a multitude of through or open voids in the interior thereof. Its form includes: generally spun and woven products such as yarns, ropes tapes (ribbons), cloths etc.; molded products such as blankets, felts, sponges or molding etc.; and products manufactured according to paper making techniques, for example, paper, mats etc., on the basis of raw cotton or bulk materials having the fiber diameter of a few 11m to several tens of pm.
  • a fibrous blank is generally identified by a bulk specific gravity (a bulk density), a size and a shape given by a width, a length, a thickness etc. and a weight per unit area or length. The bulk specific gravity (a bulk density) indicates a proportion of the weight of the fibrous blank to a bulk volume (an apparent volume) thereof.
  • a percentage of voids is also indicated which much concerns the absorption of optical energy.
  • the percentage of voids corresponds to a true porosity made of a proportion of a void volume to a bulk volume. As described above, it is calculated as follows:
  • Figure 9 is a perspective view illustrating a fibrous blank and Figure 10 is a fragmental enlarged sectional view of Figure 9.
  • Figures (33) shows a fibrous blank and (34) shows a void pore communicating with the surface of the blank.
  • the shape of void pore (34) indicates various distributions including large and small size in accordance with the shape of the fiber itself, a composition of the surface treating agent or the binder and the form of the blank (33).
  • the very excellent pressure suppressing effect is exhibited with a switch of a structure having a fibrous blank with a multitude of communication voids, disposed in the space of the structure, the voids receiving light energy of an electric arc struck.
  • This performance is much governed by the type and shape, the percentage of voids, and the specific surface area of the fibrous blank.
  • the selection of the fibrous blank is a significant problem.
  • the fibrous blank is roughly stored into an inorganic, fibrous system, a metallic fibrous system and an organic fibrous system.
  • an inorganic fibrous system there exists a natural system and an artifical system artificially worked.
  • asbestos as a mineral fiber
  • ceramic fibers ceramic fibers, mineral fibers, carbonaceous fibers and various whiskers are used.
  • metallic fibrous system there are iron and copper systems.
  • the fibrous blank as the pressure suppressing material or the light absorber in the present invention is disposed within a housing receiving light energy of an electric arc and exposed to intense heat from the considerably large electric arc, it is required that closure of the void pores communicating with the surface of the blank and a change in shape due to the melting or decomposition of the surface of the material do not occur.
  • the consumption and disappearance of the damage to the material itself are required to be small, and an amount of evolved gas is required to be small. Also it is important to render the electrical insulation high and to cause no rupture with respect to mechanical shocks.
  • the pressure suppressing material should meet various conditions.
  • the organic system has the problems relating to heat resistance, incombustibility and the generation of a gas or gases and the metallic fibers cause problems in relation to electrical insulation and withstanding voltage, so that the conditions for use and useable ranges are limited.
  • the pressure suppressing material or the light absorber in the present invention the inorganic fibrous system is most suitable which is excellent in heat resistance, insulation and mechanical strength and scarcely evolves gases even when exposed to intense heat of an electric arc.
  • inorganic fibrous system materials composed of various inorganic fibrous blanks will be described in detail on the basis of examples in experiments using the inorganic fibrous system materials put within modelled housings.
  • the experimental conditions were like the foregoing, AgW contacts were disposed at a constant gap of 10 mm within an enclosed housing of a cube having one side of 10 cm, an electric arc of a sinusoidal current with peak of 10KA was generated for 8 ms and a pressure within the housing produced with energy at that time was measured. Its characteristic was expressed by the comparison with a normalized value assumed as 1 for a pressure due to an electric arc with the inner wall of housing composed of a light-reflecting metal such as Cu, Fe, AI or the like.
  • alkali-free glass of lime alumina borosilicate material (which is generally called an E glass) fibers, good in water resistance and electric insulation, were used by twisting long fibers thereof having a true specific gravity of 2.55 g/cm 3 and a single fiber diameter of approximately 5 to 9 ⁇ m (as standardized according to JIS R 3413 (Glass Yarn)) into a glass yarn of 2251/3 counts.
  • the glass yarn was woven into a plain fabric having a density (number/25 mm) of warps (length) 34 and wefts (width) 32 (as standardized according to JIS R3414 (Glass Cloth)), a thickness of 0.19 mm, a weight of 181 g/m 2 , a bulk specific gravity of 0.953 g/cm 3 and a percentage of voids of approximately 63% to prepare a non-treated cloth. Then superposed pieces of the glass cloth with a size of 50 mm by 50 mm were used to be disposed on the wall surface of the housing so as to cover 50% of the inner wall, surface area of the housing. An electric arc was produced, and a change in pressure within the housing was measured. The resulting comparison value indicated 0.62.
  • Glass fibers were similar to those in Example 1 and long fibers having a single fiber diameter of approximately 6 to 13 pm were twisted into a yarn (of #75 1/5 counts, and wefts 150 1/9) which was woven into a plain fabric having a density (number/25 mm) of warp 12 and wefts 12, a thickness of 0.32 mm, a weight of 310 g/m 2 , a bulk density of 0.968 g/cm 3 and a percentage of voids of approximately 62% to prepare a non-treated glass cloth.
  • Six superposed pieces of the glass cloth with a size of 50 mm by 50 mm were used to be disposed on the wall surface of the housing so as to cover 50% of the inner wall surface area of the housing. An electric arc was produced and a change within pressure in the housing was measured. The resulting comparison value indicated 0.65.
  • alkali-containing sodium borosilicate glass which is generally an A glass
  • alkali-containing sodium borosilicate glass which is generally an A glass
  • fibers were used by adding a small amount of an organic binder to raw cotton made of short fibers thereof having a type specific gravity of 2.46 g/cm 3 and a single fiber diameter of 10 to 15 pm, and working a molded glass blanket having a bulk specific gravity of 0.012 to 0.024 g/cm 3 and a molded glass board having a bulk specific gravity of 0.032 to 0.064 g/cm 3 into sizes of 50 mm by 50 mm. They were disposed on the wall surfaces of housing so as to cover 50% of the inner wall surface area of the housing. An electric arc was produced, and a change in pressure within the housing was measured. The resulting comparison values indicated 0.52 with the roll and 0.55 with the board.
  • ceramic fibers of alumina silica material excellent in refractoriness, heat insulation, chemical resistance and electric insulation, and a raw cotton bulk material of long ones thereof having a true specific gravity of 2.7 g/cm 3 and a single fiber diameter of approximately 3 11m were added with a small amount of inflammable organic fiber and woven into a ceramic fiber cloth or tape having a thickness of 2 mm through reinforcing strings.
  • the material having a size of 50 mm by 50 mm was disposed on the inner surface of the housing so as to cover 50% of the inner surface of the housing. An electric arc was produced, and a change in pressure within the housing was measured. The resulting comparison value indicated 0.60.
  • a ceramic fiber bulk material similar to that in Example 4 was molded into a layer after which it was needling processed into a blanket having a bulk specific gravity of 0.13 g/cm 3 and a thickness of 12.5 mm.
  • the bulk material was added with an inorganic binder and molded into a board having a bulk specific gravity of 0.3 g/cm 3 and a thickness of 10 mm.
  • the bulk material was processed with a minute amount of an organic binder and molded into a felt having a bulk specific gravity of 0.10 g/cm3 which felt was worked to a thickness of 10 cm.
  • Each of them having a size of 50 mm by 50 mm was disposed on wall surface of the housing so as to cover 50% of the inner surface of the housing. An electric arc was produced, and a change in pressure within the housing was measured. The resulting comparison value indicated 0.55 with the blanket, 0.59 with the board and 0.56 with the felt.
  • synthetic acrylic fibers passed through the flame resisting step in air at 200 to 300°C to form flame resisting fibers, which passed further through the carbonizing step in an inert gas at 1,000 to 1,500°C to form carbon fibers excellent in heat and corrosion resistances.
  • the carbon fibers had a true specific gravity of 1.7 g/cm 3 and a single fiber diameter of 12 to 24 pm, and were twisted into a yarn of high strength carbon fiber with a filament number of 1,000.
  • the yarn was woven into a plain fabric having a density (number per 25 mm) of warps 22.5 and wefts 22.5, a thickness of 0.15 mm, a weight of 120 g/m 2 , a bulk specific gravity of 0.8 g/cm 3 and a percentage of voids of approximately 53% resulting in a non-treated cloth of carbon fibers. Thirteen superposed pieces of the cloth with size of 50 mm by 50 mm were used to be disposed on the wall surface area within the housing. An electric arc was produced, and a change in pressure within the housing was measured. The resulting comparison value indicated 0.63.
  • a yarn with a filament number of 1000 formed of carbon fibers similar to those in Example 7 was woven into a plain fabric having a density of warps 12.5 and wefts 12.5, a thickness of 0.27 mm, a weight of 200 g/m 2 , a bulk specific gravity of 0.741 g/cm 3 and a percentage of voids of approximately 56% resulting in a non-treated cloth of carbon fibers.
  • Eight superposed pieces of the cloth with a size of 50 mm by 50 mm were used to be disposed on the wall surface of the housing so as to cover 50% of the surface area within the housing. An electric arc was produced, and a change in pressure within the housing was measured. The resulting comparison value indicated 0.65.
  • the yarn was plainly woven into an asbestos cloth having a thickness of 2.9 mm, a weight of 850 g/m 2 , a bulk specific gravity of 0.425 g/cm 3 and a percentage of voids of approximately 83% (as prescribed in Class No. 2 according to JIS R3451 (Asbestos Cloth)).
  • the asbestos cloth was used with a size of 50 mm by 50 mm to be disposed on the wall surface of the housing so as to cover 50% of the inner surface area of the housing. An electric arc was produced, and a change in pressure within the housing was measured. The resulting comparison value indicated 0.58.
  • the voids in various inorganic fibrous system materials have the great effect of absorbing light energy to reduce the pressure in the interior of switches.
  • the fibrous blanks are good in their characteristic of pressure absorption even though they are in the form of spun and woven products such as a cloth, a tape etc., or of molded products such as a blanket, a board, a felt etc.
  • the thicker the thickness of the fibrous blank the more the characteristic thereof will be increased.
  • a blanket, a board, a felt or the like having bulk specific gravities ranging from about 0.01 to 0.5 g/cm 3 , a percentage of voids of not less than approximately 80% and large specific surface area is used as a sound absorbing material, a heat insulating material etc. and can be said to be good pressure suppression materials.
  • These molded products are composed of a fibrous bulk material, as raw cotton, an inorganic or an organic binder and a surface treatment agent. They desirably include the organic component as small as possible in view of an amount of a generated gas or gases with the surface not clogging with a binder other than the fibrous matter.
  • spun and woven products such as a cloth, a tape, etc., having generally the bulk specific gravity of 0.5 to 1.5 g/cm 3 (which is greater than that of molded products), and 40 to 90% of communicating voids and high specific surface area (without using a surface treatment agent), are composed of fibers.
  • These products are standardized and are the optimum materials in view of the quality and form of the material itself.
  • the bulk specific gravity per unit volume or unit area, the percentage of voids and the specific surface area depend upon the type of fibers used in the blank, the aggregation of the fibers, the diameter and length of single fiber, the yarn diameter, the manner of weaving, the number of intertexture of yarn, the density of intertexture etc. and there are may kinds of forms of products.
  • the woven clothes, and tapes are in the form of a plain fabric, a satin fabric, a twill fabric, a gauze fabric etc. and have different spacings between warps and between wefts.
  • the pressure suppressing material is preferably of a plain fabric because warps crossing the wefts to lie above the latter alternate those crossing the wefts to lie below the latter as do the wefts, thereby increasing the strength of the resulting texture, and the spacings between the warps or between the wefts are distributed on the plain fabric to render the number thereof per unit area large.
  • the characteristic tendency of said examples to exhibit the pressure suppressing effect is common to spun and woven products and molded products in view of the form of product, and can be said in conjunction with all the inorganic fibrous system materials. It is important that the shape of the void pores has a size somewhat exceeding the wavelength range of light to be absorbed, and that the proportion of open voids occupying the surface of the blank or the specific surface area of the open voids is large. In the absorption of light within the void, a deep void is effective and particularly communicating voids are desirable.
  • the void pores which are suitable are those having an order of magnitude somewhat exceeding the wavelength of the light. Also fibrous materials in which the number of open pores occupying the surface is not less than 40% of the total number of voids, are suitable for absorbing light emitted by an electric arc.
  • inorganic fibrous blanks for example, fibers of alkali glass of soda line borosilicate material (which is generally called a C glass), alkali-resisting glass of Si0 2 -R 2 0-ZrO 2 system, and high elasiticity glass and optical glasses and others as special materials having the glass fiber nature.
  • the glass fibers themselves permit the transmission of light and possess the peculiar feature that they absorb light energy through the boundary surface thereof.
  • the ceramic fibrous materials there can be used, a high refractory alumina system, a zirconia system, a silica system, a boron system and a silicon nitride system fiber other than the alumina-silica system.
  • the carbon fiber material there can be used, in addition to a carbon fiber, graphitic fibers with the high refractoriness and the high modulus of elasticity, prepared through the step of graphitizing carbon fibers in an inert gas at a high temperature of 2,500 to 3,000°C.
  • the carbon and graphite fibers have electric conductivities, but they have the advantages that they have high melting points, are light and high in strength.
  • the graphite fiber is black and efficient in absorbing optical energy.
  • asbestos materials there can be used, in addition to chrysotile asbestos, crocidolite asbestos of Na 2 Fe s Si a 0 22 and ammocite asbestos of (FeMg) 6 Si 8 O 22 (OH) 2 .
  • the artificial mineral fiber there can be used rock wools obtained by melting and fibrizing natural rocks such as basalt and andesite, and slag wools obtained by fibrizing melted slag upon refining metals.
  • Raw materials for these fibers are inexpensive and excellent in refractoriness and there are advantages as fibrous materials used as general fibrous materials.
  • whiskers of the SiC material and others can be also used.
  • the inorganic fibrous system materials such as said glass fibers, ceramic fibers, carbonaceous fibers, mineral fibers, asbestoses, various whiskers etc. can be used, by winding spun and woven products such as the yarn, roving material, rope (cord), braid etc. other than the cloth and tape (ribbon) as the form of products, to suitable thickness, connecting and stacking them.
  • Also there can be used molded, worked products and products manufactured like paper such as a sponge, molding a paper mat etc. other than a blanket, a bord and a felt as well as bulk materials themselves by means of a measure such as filling or the like.
  • the glass fibers, carbonaceous fibers, ceramic fibers, mineral fibers, asbestos fibers etc. as described above are also in many cases used with electrically insulating materials, construction and civil materials and industrial structural materials as composite materials for plastic reinforced fibers, concrete or cement reinforced material etc. But they are made into materials tending to reduce in voids to be dense and therefore lessen the effect as the pressure suppression material for absorbing optical energy.
  • the two may be put together.
  • one may be used as a core material to reinforce the other.
  • the inorganic high porous material or the inorganic fibrous system material is broken or produces a minute powder to be attached to a movable mechanism or mechanisms of a switch or to be caught by contacts.
  • Paraffin was impregnated into or coated on the surface layer of the porous pottery of cordierite matter obtained by Example 1 to cover or fill open pores and the paraffin attached to the surface was removed by grinding or polishing and therewith the surface was rendered smooth and a polishing powder or the like was removed. Thereafter the surface was coated with a graze paste of the K 2 0-CaO-MgO-AI 2 0 3 -SiO 2 systems and fired at a temperature of from 1150° to 1250°C to be brazed thereby to compact and strengthen peripheral portions of the open pores. At the firing step the paraffin attached to or filling the open pores is burnt down to leave the open pores on the surface in the state approximating that before the brazing.
  • FIG 11 is another embodiment of the present invention and a sectional view of a circuit interrupter using a light absorber of an inorganic high porous material or an inorganic fibrous system material.
  • (35) is a light absorber of an inorganic high porous material or an inorganic fibrous system material and minutely the material described in Examples 1 to 13 and disposed on one part of wall surfaces on both sides of housing (3) and along these wall surfaces.
  • the inorganic high porous material or the inorganic fibrous system material (35) is desirably disposed at a position where it directly receives energy of light of an electric arc (32) but it may be disposed at a position where it receives light reflected from the wall surface or the like.
  • an exhaust hole (36) (see Figure 1) may be omitted which hole are normally disposed on the housing (3) to discharge a gas to the exterior of the housing (3) upon the generation of an electric arc.
  • Figures 12 to 16 show another embodiment of the present invention in which a light absorber (37) of a high porous material or a fibrous system material of the inorganic matter is disposed on the inner surface of the switch.
  • Figure 14 is a sectional view taken on the line A-A of Figure 13
  • Figure 16 is a sectional view taken on the line B-B of Figure 5.
  • (1) is a cover and (2) is a base. They are formed of synthetic resistive materials respectively and have a turnable operating handle (22) on the central portion, identical to that of said Figure 1.
  • Said light absorber (37) is formed into a plate and installed on the inner surfaces of the cover (1) and the base (2) as in Figure 13 to Figure 16. But a place of installation is a place easy to be most irradiated with light of the electric arc in Figure 13 and in short disposed adjacent to the stationary contact (6) and the movable contact (9).
  • the light absorber has been disposed on the inner wall of the housing in this embodiment the light absorber may be used on one part or the whole of the housing.
  • a reinforcing sheet may be integrally joined to the rear surface of the light absorber and in short that surface opposite to that irradiate with light from the electric arc.
  • the reinforcing sheet copper, aluminum, stainless steel, silicon steel sheet, iron or the like may be used. They may be joined by using a bonding agent but heating joining means is effective.
  • the heating joining means is to insert a copper sheet between the light absorber and the reinforcing sheet and heat it with heat at about 1200°C whereupon the melted copper easily adheres to the reinforcing sheet and also penetrated into the structure of the light absorber resulting in the integral joining.
  • the present invention is not always limited to circuit interrupters and can be applied to the housing of current limiters, electromagnetic switches etc. and usually what generates an electric arc within a small-sized housing.

Landscapes

  • Arc-Extinguishing Devices That Are Switches (AREA)
  • Glass Compositions (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Claims (9)

1. Commutateur comprenant au moins une paire d'éléments de contact (5, 8), chacun formé d'un conducteur électrique et d'un contact (6, 9) qui lui est fixé, lesdits éléments de contact accomplissant les opérations d'ouverture et de fermeture, un boîtier (3), pour recevoir lesdits éléments de contact, et une matière poreuse montée dans le boîtier, caractérisé en ce que la matière poreuse (35) est configurée pour servir d'absorbeur de la lumière et est disposée en une position où ledit absorbeur de la lumière reçoit l'énergie de la lumière d'un arc électrique (32) produit lors des opérations d'ouverture et de fermeture desdits éléments de contact, ledit absorbeur de la lumière étant formé d'au moins l'une des matières inorganiques très poreuses ayant une porosité apparente de pas moins de 35% d'un système de matières inorganiques fibreuses et d'ébauches poreuses.
2. Commutateur selon la revendication 1 où la matière inorganique très poreuse a la porosité apparente de 40 à 70% de l'ébauche poreuse.
3. Commutateur selon la revendication 1 où la matière inorganique très poreuse est au moins l'une parmi les poteries, les articles réfractaires, les verres, des éléments durcis de ciment qui sont poreux.
4. Commutateur selon la revendication 1 où la matière inorganique très poreuse a un diamètre moyen des pores de quelques centaines de nanomètres (quelques milliers d'angstrôms) à quelques milliers de µm.
5. Commutateur selon la revendication 1 où la matière du système inorganique fibreux a un pourcentage des vides de pas moins de 40% de son ébauche fibreuse.
6. Commutateur selon la revendication 1 où la matière du système inorganique fibreux a une densité apparente de 0,01 à 1,5 g/cm3 de son ébauche fibreuse.
7. Commutateur selon la revendication 1 où la matière du système inorganique fibreux est une ou plusieurs des fibres de verre, fibres de céramique, laines minérales, laines de scories, fibres carbonées et poils.
8. Commutateur selon la revendication 1 où la surface de l'absorbeur de la lumière est tassée.
9. Commutateur selon la revendication 1 où l'absorbeur de la lumière est disposé en une position où l'absorbeur de la lumière reçoit directement l'énergie de la lumière de l'arc électrique.
EP83900281A 1982-01-14 1983-01-11 Commutateur Expired EP0098308B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP562682A JPS58121524A (ja) 1982-01-14 1982-01-14 開閉器
JP5626/82 1982-01-14
JP6441882A JPS58181248A (ja) 1982-04-15 1982-04-15 開閉器
JP64418/82 1982-04-15

Publications (3)

Publication Number Publication Date
EP0098308A1 EP0098308A1 (fr) 1984-01-18
EP0098308A4 EP0098308A4 (fr) 1986-10-02
EP0098308B1 true EP0098308B1 (fr) 1988-08-03

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EP83900281A Expired EP0098308B1 (fr) 1982-01-14 1983-01-11 Commutateur

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EP (1) EP0098308B1 (fr)
KR (1) KR870000097B1 (fr)
DE (1) DE3377601D1 (fr)
WO (1) WO1983002525A1 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4516002A (en) * 1982-04-15 1985-05-07 Mitsubishi Denki Kabushiki Kaisha Circuit breaker with arc light absorber
US4521653A (en) * 1982-04-15 1985-06-04 Mitsubishi Denki Kabushiki Kaisha Circuit breaker with arc light absorber
US4516003A (en) * 1982-06-15 1985-05-07 Mitsubishi Denki Kabushiki Kaisha Circuit breaker with arc light absorber
FR2576721B1 (fr) * 1985-01-30 1987-04-17 Centre Nat Rech Scient Paroi de chambre de coupure de disjoncteur et chambre de coupure de disjoncteur munie d'une telle paroi
IT1291014B1 (it) * 1997-01-15 1998-12-14 Eltek Spa Dispositivo elettromeccanico e relativo metodo di isolamento
JP4957072B2 (ja) * 2006-05-11 2012-06-20 富士電機機器制御株式会社 回路遮断器
EP2597663A1 (fr) 2011-11-28 2013-05-29 Eaton Industries (Netherlands) B.V. Absorbeur d'énergie à arc

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5149068B1 (fr) * 1969-12-12 1976-12-24
JPS5372176U (fr) * 1976-11-19 1978-06-16
JPS5517450B1 (fr) * 1971-02-22 1980-05-12

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS313147Y1 (fr) * 1954-12-24 1956-03-01
DE1933529A1 (de) * 1969-07-02 1971-01-21 Bbc Brown Boveri & Cie Lichtbogenkammer aus Siebkeramik

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5149068B1 (fr) * 1969-12-12 1976-12-24
JPS5517450B1 (fr) * 1971-02-22 1980-05-12
JPS5372176U (fr) * 1976-11-19 1978-06-16

Also Published As

Publication number Publication date
KR840003529A (ko) 1984-09-08
WO1983002525A1 (fr) 1983-07-21
KR870000097B1 (ko) 1987-02-10
DE3377601D1 (en) 1988-09-08
EP0098308A4 (fr) 1986-10-02
EP0098308A1 (fr) 1984-01-18

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