Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01C—RESISTORS
  • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
  • H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
  • H01C7/12—Overvoltage protection resistors; Arresters

Definitions

• the invention relates to an electrical surge arrester, in particular for medium voltage, with a functional block and an elastically expandable housing made of an insulating material surrounding the latter, in which at least one embedded reinforcing element for mechanical reinforcement is provided separately from the functional block.
• a surge arrester with an elastically expandable housing is known for example from E 0 233 022.
• a surge arrester is described there, in which the functional block is first firmly surrounded by a fiber-reinforced resin and the blank thus produced is introduced into an elastic sleeve. After use, the functional block can hardly be freed from the resin that is firmly attached to it, so that great problems arise with environmentally friendly disposal (see specialist article "Disposal and recycling of plastic waste", bulletin SEV / VSE ( 1992) 15, 31.7.).
• An electrical surge arrester with a functional block and an elastic housing made of an insulating material is known from EP 0 545 038 A1. Reinforcing elements in the form of plastic strips or plastic tapes are cast into the insulating housing. It is therefore difficult to separate the reinforcing elements from the housing of the high-voltage arrester when disposing of the arrester.
• the invention is therefore based on the object of creating an electrical surge arrester which is easy to disassemble and in which the parts consisting of different materials can be easily separated for recycling purposes.
• the object is achieved according to the invention in that the reinforcing element (s) is held in a force-fitting manner by elastic expansion of the insulating material housing and is / are not integrally connected to it.
• the functional block consisting of the actual diverter elements is pressed into the housing with an elastic expansion of the housing walls and held by the elastic pressure of the housing walls.
• the functional block can easily be removed again from the housing by means of elastic expansion of the housing walls.
• the functional block which normally consists of a metal oxide and metal parts, can be disposed of or reused separately from the housing, which consists of an insulating material. Installation during the manufacture of the drain is also simplified by simply inserting the functional block into the housing.
• the reinforcing element is functionally and spatially separated from the functional block of the drain and embedded in the housing body.
• the functional block itself does not need any mechanical reinforcement, for example in the form of a fiber-reinforced plastic layer, since the metal oxide disks can be glued to one another, for example.
• the housing or the conductor as a whole is given the required mechanical stability by the reinforcing element (s).
• the housing consists of an elastic cast body.
• Such a body can be produced easily and inexpensively from elastic material.
• the casting may be either of which it is composed by the properties of the material or by ⁇ a specific shape, for example the shape of a bellows, can be designed to be resilient.
• the housing has a first recess for receiving the functional block and a second recess for receiving a reinforcing body.
• Both the functional block and the reinforcement element (s) can be pushed axially out of the corresponding recess for separate disposal.
• the housing has shielding ribs on its outside.
• This known measure for extending the creepage distances on the outside of the housing of an arrester can advantageously be taken in that the shielding ribs are integrated in the housing body.
• a further advantageous embodiment of the invention provides that the housing consists of an optionally filled silicone rubber or ethylene-propylene-diene monomer or a mixture of both substances.
• Silicone rubber and EPDM have excellent mechanical and in particular also dielectric properties and are particularly suitable for use in a surge arrester according to the invention because of their long-term stability, good environmental compatibility and simple processability.
• the invention can also be advantageously designed in that the spaces between the functional block and the housing are largely filled by a partially plastically deformable elastic mass. This on the one hand makes it easier for the functional block to slide into the recesses in the housing body, and on the other hand the remaining gaps are filled so that electrical discharges in any cavities that arise between the functional block and the housing are avoided.
• the plastically deformable elastic mass can consist, for example, of a material based on silicone.
• a further advantageous embodiment of the invention provides that the functional block is connected at least at one of its ends to a connection contact by a flexible electrical conductor, in particular a metal spring.
• FIG. 1 shows a schematic longitudinal section through a surge arrester according to the invention
• FIG. 2 shows a cross section of the surge arrester shown in FIG. 1
• FIG. 4 shows a surge arrester in which the function block is electrically connected at its ends via spiral springs.
• the surge arrester has a functional block 1, which consists of metal oxide disks 2, 3 glued together.
• the functional block 1 is arranged in a recess 4 of a silicone rubber casting 5.
• the recess 4 is smaller in diameter than the diameter of the functional block 1, so that the cast body 5 is elastically widened when the functional block 1 is inserted and holds the functional block 1 in a force-fitting manner.
• the functional block 1 is inserted into the recess 4 of the cast body 5 by expanding the cast body 5 by suitable mechanical means.
• the cast body 5 also has a recess 6 for a reinforcing body 7, which is also held elastically in the recess 6 of the expanded cast body 5.
• the reinforcing element 7, which is formed, for example, from a glass fiber-reinforced plastic rod, holds two metallic connection plates 8, 9, between which the housing 5 of the surge arrester is clamped.
• the connection plates 8, 9 each carry a connection bolt 10, 11 for making electrical contact with the surge arrester.
• the surge arrester can be oval in cross-section as shown in FIG. 2, which results in good dielectric strength.
• the cross section can also be designed as shown in FIG. 3, which results in a minimal material consumption for the housing.
• the surge arrester can also be constructed in such a way that (see FIG. 4) the function block is mechanically and elastically coupled to the connection plates 8, 9 via spiral springs 13, 14 in order to avoid high mechanical loads on the function block 1 during assembly and operation.

Landscapes

• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Thermistors And Varistors (AREA)
• Emergency Protection Circuit Devices (AREA)
• Dowels (AREA)
• Insulators (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=6490491

Family Applications (1)

Country Status (7)

Families Citing this family (4)

Family Cites Families (17)

• 1993
  • 1993-06-11 DE DE4319986A patent/DE4319986A1/de not_active Withdrawn
• 1994
  • 1994-05-26 AT AT94916141T patent/ATE150579T1/de not_active IP Right Cessation
  • 1994-05-26 DK DK94916141.8T patent/DK0702841T3/da active
  • 1994-05-26 EP EP94916141A patent/EP0702841B1/fr not_active Expired - Lifetime
  • 1994-05-26 ES ES94916141T patent/ES2102226T3/es not_active Expired - Lifetime
  • 1994-05-26 WO PCT/DE1994/000607 patent/WO1994029888A1/fr not_active Ceased
  • 1994-05-26 DE DE59402163T patent/DE59402163D1/de not_active Expired - Fee Related
• 1995
  • 1995-12-08 NO NO955001A patent/NO955001D0/no unknown

Non-Patent Citations (1)

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