Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/662—Housings or protective screens
  • H01H33/66261—Specific screen details, e.g. mounting, materials, multiple screens or specific electrical field considerations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/24—After-treatment of workpieces or articles
  • B22F3/26—Impregnating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
  • B22F5/10—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of articles with cavities or holes, not otherwise provided for in the preceding subgroups
  • B22F5/106—Tube or ring forms
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/0425—Copper-based alloys
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
  • H01H33/60—Switches wherein the means for extinguishing or preventing the arc do not include separate means for obtaining or increasing flow of arc-extinguishing fluid
  • H01H33/66—Vacuum switches
  • H01H33/662—Housings or protective screens
  • H01H33/66261—Specific screen details, e.g. mounting, materials, multiple screens or specific electrical field considerations
  • H01H2033/66269—Details relating to the materials used for screens in vacuum switches

Definitions

• the invention relates to a usable as a shield in a vacuum interrupter tubular member made of a first metal and a method for producing such a component.
• a vacuum interrupter is ⁇ be known, the shield is uniformly made of a copper-chromium material with a melting copper and chromium content of each ⁇ wells 50%.
• the present invention seeks to provide a shield for a vacuum switching ⁇ tube, which combines the advantages of different metals.
• This object is achieved in a usable as a shield in a vacuum interrupter tubular member made of a first metal in that the component between two end regions has a central portion having a second metal having a melting temperature, the hö ⁇ forth than the melting temperature of the first Metal is.
• the end regions consist of copper and between the end regions of a middle Section of a copper and chromium-containing alloy is present.
• a shield which consists of copper-chromium in the relevant contact gap area.
• the shield is characterized in the contact gap area by a high erosion resistance over pure copper.
• a method for producing such a tubular component which can be used as a shield provides as the first method step that in a molten mold with a tubular cavity an axially first portion of the cavity is filled with a low-melting metal, wherein in a further step in the in axia ⁇ ler direction adjoining portion of the cavity a Herge ⁇ imputed tubular porous blank is by means of a powder of refractory metal is introduced, and wherein further provided a low-melting metal in the subsequent axially adjacent section of the cavity before the Contents of the melt mold in vacuum for a time sufficient for partial melt diffusion into the porous blank is brought to a sufficiently high temperature, and wherein finally after cooling of the melt mold, a tubular component is removed for further processing.
• FIG. 1 is a partially sectioned side view of a vacuum interrupter according to an embodiment of the invention
• FIG. 2 shows a press mold for producing a pressed article, in particular a CrCu blank
• Fig. 3 is a melt mold for producing a shield in the form of a metallic, predominantly rotationally symmetrical shell, in which the material composition behaves heterogeneously only in the axial direction.
• Fig. 1 shows a partially sectioned side view of a vacuum interrupter 1, which has a two-part hollow cylindrical ceramic housing 2 a and 2 b, the housing parts 2 a and 2 b are each sealed at the end by metallic cover 3 and 4 vaku- umdicht, so that a vacuum interrupter chamber 5 is formed.
• the lid 3 is of a fixed contact rod
• the lid 4 is penetrated by a switching rod 8, which carries a moving contact 9.
• the moving contact 9 and the fixed ⁇ contact 7 have slots to generate a deletion of a ge ⁇ arc pulled supporting magnetic field.
• the shift rod 8 and the moving contact 9 are longitudinally guided ⁇ Lich, so that the moving contact 9 can be transferred from its in the disconnected position shown in Fig. 1 out in a contact position in which the moving contact 9 on the fixed contact
• a shield 11 is provided.
• the cylindrical shield 11 is formed as a sleeve with three sections 12, 13 and 14.
• the shielding 11 surrounds exhaust from the fixed contact 7 and the contact 9 Move ⁇ existing contact arrangement.
• the shield 11 shown in FIG. 1 inside the vacuum interrupter 1 thus serves to avoid ceramic vapor deposition of the hollow cylindrical ceramic housing 2a and 2b.
• the shield 11 is made of a metal, in particular copper or a copper-containing alloy, such as copper-chromium.
• the end portions or portions 12, 14 are made of copper and the middle portion 13 is made of a copper-chromium alloy.
• the method for producing the shield 11 leads to a shield 11 whose material composition is behaves heterogeneously in the axial direction.
• a section 12 made of copper In the shield 11 in the axial direction alternately follow a section 12 made of copper, a section 13 made of copper-chromium, and then a section 14, which again consists of copper.
• the structure of the shield 11 of three sections 12, 13 and 14 makes it possible to realize by means of the central portion 13 a ⁇ telwall for vacuum interrupters so that the shield 11 only in the contact gap region of the contacts 7 and 9 consists of copper-chromium.
• Copper-chromium has the advantage of increased burn-off resistance of the copper chromium, reduced conductivity for reducing eddy currents, and furthermore the advantage of better properties of copper-chromium in interactions of the switching plasma with the shield 11, compared to a copper vapor shield only.
• the process for the preparation of the three sections 12, 13, 14 having shield 11 begins with a tube section, pressing or blank of pressed refractory metal, for example, mechanically compacted Chrompul ⁇ ver or sintered chromium powder is prepared.
• a press mold 21 made of steel or a similarly constructed graphite sinter, shown schematically in FIG.
• the mold 21 essentially consists of a base part 23 with a flat bottom and an annular circumferential stop 25.
• the stopper 25 forms a cylin ⁇ derförmige recess into which a cylinder mold core 27 can be inserted. Together with a stop 25 on the outside embracing hollow cylinder 29 of the cylinder mold core 27 forms an annular space 31.
• the hollow cylinder 29 is supported on a flange 33 of the base member 23 with the interposition of a rubber ring 35.
• a pipe section blank or pressing is made by means of the mold 21 or a graphite sinter, not shown in the drawing, by the annular space 31 is filled, for example, with a mixture of chromium powder and copper powder to a predetermined filling level.
• the powder present in the annular space 31 is then compressed.
• the copper powder may have a grain size of 40-250 microns and the chromium powder a grain size of 50-300 microns.
• Fig. 3 schematically illustrates a melt mold 41 for producing the shield 11 with the sections 12, 13 and 14.
• the melt mold 41 has a circular disk-shaped bottom plate 43 with a centering hole 42 and a circular peripheral skirt 44.
• the bottom plate 43 and the others in the following Parts of the melt mold 41 which are still described are preferably made of hard graphite.
• the centering hole 42 serves to receive a pin 47 formed on a mold guide column 46.
• the skirt 44 serves to guide a guide cylinder 48 into which a lower mold part 49, a middle mold part 51, an upper mold part 53 and a final mold part 55 are inserted ,
• Each of the mold parts 49 to 55 consists of an inner ring part 54 guided on the mold guide column 46 and an outer ring part 56 guided by the guide cylinder 48. They contact each other along annular surfaces which engage one another with recesses and projections which can be seen in the drawing.
• the mold parts 49 to 55 thus each consist of an outer ring member 56 which is supported against the guide cylinder 48, and in each case an inner ring member 54 which is guided by the mold guide column 46.
• a low melting ⁇ ing metal This may be a copper powder or a section of a copper tube.
• the tubular gap portion 63 between the two annular parts of the central mold part 51 serves to receive high-melting metal such as a tubular pressing 65, for example, in the mold 21 from a mixture of copper powder with a grain size of 40-300 microns and chromium powder with a grain size of 50-300 microns was produced.
• a compact 65 it is also possible to use a blank which has been produced by sintering chromium powder.
• a chromium powder with a grain size of 50-300 microns at a temperature of 125O 0 C for 60 min are annealed in a vacuum furnace, not shown in the drawing.
• the dimensions of the blank or compact 65 are chosen so that it abuts the circumferential shoulder 59 and can not fall into the gap of the lower mold part 49, even if it is only partially filled with a material.
• the gap portion 67 in the region of the mold parts 53 and 55 similar to the tube-shaped gap in the Be rich filled ⁇ 61 with a low-melting metal in whole or in part.
• This may again be a copper powder or a section of a copper tube.
• the melt mold 41 When the melt mold 41 is vacuum-heated to the melting temperature of the low-melting metal, in particular the copper, is heated, the molten metal fills the melt mold 41 in the lower portion 61 from.
• the low-melting metal, in particular copper, in the upper region 67 then diffuses through the pressure 65 and fills out its pores.
• an alloy of the low-melting and high-melting metal is formed in the tubular gap section 63.
• the alloy can be changed in their composition.
• the low-melting metal from the upper portion 67 is used as an alloy depot. A sufficient amount of material must be kept from the ⁇ sem basically in the upper region 67 to a homogeneous structure si ⁇ cher creative.
• the exposure time of the molten phase should be extended until the blank or tubular pressure is 65 completely saturated by the low-melting metal, in particular ⁇ sondere copper.
• the melting process described at a temperature of 1150 to 125O 0 C with a holding time of 20 to 60 min is carried out in vacuo, in order to prevent oxidation of the metals used, in particular the copper and the chromium. If this does not happen in a vacuum, no connection of the metals takes place.
• the shield 11 produced in the manner described above forms a hollow cylindrical shell, in which metal ⁇ metallic materials alternate in the axial direction, the transitions to the central portion 13 are abrupt. At a transition is always a low-melting metal and an alloy of the low-melting and high-melting metal.
• the described combination of copper-copper-chromium-copper represents a shield 11, which is used as a vapor shield in vacuum interrupters 1 in a particularly advantageous manner to achieve increased erosion resistance and reduction of eddy currents in the relevant contact ⁇ gap area.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• High-Tension Arc-Extinguishing Switches Without Spraying Means (AREA)
• Powder Metallurgy (AREA)
• Contacts (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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• 2007
  • 2007-09-27 DE DE200710047473 patent/DE102007047473B3/de active Active
• 2008
  • 2008-09-24 WO PCT/EP2008/062742 patent/WO2009043769A1/de active Application Filing
  • 2008-09-24 EP EP08804652A patent/EP2191486A1/de not_active Withdrawn
  • 2008-09-24 CN CN200880109241A patent/CN101809701A/zh active Pending

Non-Patent Citations (1)

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