The disclosure is based on the prior art according to EP 1 403 891 A1, which discloses a circuit breaker in which exhaust gas from an arcing area is passed through a hollow contact into a concentrically arranged exhaust volume, and from there into a quenching chamber volume located further outward. In order to increase the disconnection rating, at least one intermediate volume and, possibly, an additional volume is or are arranged concentrically between the hollow contact and the exhaust volume, separated from one another by intermediate walls which have holes or openings through which gas can pass. The exhaust gases are swirled by the switching gases flowing out radially from the inner and to the outer volumes, and a large amount of thermal energy can be transferred to the intermediate walls of the volumes. The aperture openings between the hollow-contact volume, the intermediate volume and, if appropriate, the additional volume are arranged offset with respect to one another on the circumference. The aperture openings between the additional volume and the exhaust volume are arranged offset with respect to one another on the circumference and/or in the axial direction. This results in meandering as well as spiral exhaust-gas paths being predetermined, with the dwell time for which the exhaust gas remains in the exhaust area being increased, and with the heat transfer from the exhaust gas being improved. Furthermore, the holes can be closed by means of panels in the form of perforated metal sheets, in order to produce a multiplicity of radially directed gas streams or gas jets, which strike the opposite wall, are swirled at the impact points, and thus intensively cool the hot gas. The intermediate volume, which improves the cooling, is arranged in the exhaust area on the drive contact side. A second intermediate volume may also be provided on the fixed-contact side. Overall at least one further intermediate volume is also required in the circuit breaker, that is to say in addition to the hollow-contact volume, the exhaust volume and the switching chamber volume, in order to achieve efficient exhaust-gas cooling.
DE 25 07 163 A1 discloses an electrical switch which has linings which are arranged on the inside of the switching chamber enclosure and are composed of highly thermally conductive metal. The linings are used as coolers, temperature distributors, field distribution rings, shields for protection of the insulating surfaces against corrosion and diffusion, and as an element for deflection of the switching gas flow. In this case, the switching gas flow is guided in a laminar fashion along the linings. No baffle wall for vortex formation is provided in the switching gas flow.
DE 101 56 535 C1 discloses an electrical switch which has a flow guidance device, by means of which partial gas streams are guided towards one another, with vortices being formed in consequence. The crossing-over of the partial gas streams and their swirling and vortex formation replaces a heat-absorbing baffle wall. For additional vortex formation, the flow guidance device may have small vortex-formation bodies arranged adjacent to outlet openings and influencing the guidance of the quenching gas. These vortex-formation bodies are not used to extract heat from the switching gas.
In utility model DE 1 889 068 U a switch disconnector with improved exhaust-gas cooling is disclosed. The cooling apparatus has a plurality of tubes which are arranged concentrically in the gas outlet channel and each have diametrically opposite outlet openings, so that the switching gases pass through a labyrinthine path with numerous deflections while flowing out in a laminar form, and have to cover large surface areas of the cooling tubes. This arrangement therefore substantially lengthens the outlet-flow path, and enlarges the cooling surface area in the exhaust. The outlet openings are chosen to be broad, in order to keep the switching gas backpressure low. The flow channels between the cooling tubes are chosen to be narrow, in order to provide a large cooling surface area for the switching gas. Overall, the flow is kept in the laminar range, and the switching gas is cooled by laminar convective heat transfer to the cooling tubes.
EP 0 720 774 B1 discloses a high-voltage circuit breaker having a hollow-cylindrical metal wire mesh or metal body as a heat sink for switching gases. In addition, a dielectric body is provided, is located further inward, does not allow quenching gas to pass through, shields the metal body from the quenching gases, precools the quenching gases by material vaporization, and thus counteracts overheating of the metal wire mesh. As it flows through the metal wire mesh, the quenching gas is cooled further by interaction with the metal surface of this mesh. Owing to the large number of aperture openings, the flow resistance of the metal wire mesh is low, again resulting in laminar flow.
DE 102 21 580 B3 discloses a high-voltage circuit breaker having an interrupter unit, in which the exhaust gases are deflected twice through 180°. In order to improve the cooling of the gases, a concentrically arranged, hollow-cylindrical perforated metal sheet through which flow passes radially is provided on the fixed-contact side. The perforated metal sheet is again used as a heat sink, which extracts heat from the quenching gas without increasing the flow resistance for the quenching gas and without disturbing the laminar quenching-gas flow.
USPTO Backgrounds
USPTO Backgrounds