Patent GB-517633-A (GB)
Title: Improvements in or relating to hydroplane vessels
IPC: B63B1/26
Filed: 1938-08-02
Abstract: 517,633. Gas - blast switches; switchgear structures. REYROLLE & CO., Ltd., A., and HARLE, J. A. Aug. 2, 1938. No. 22811. [Class 38 (v)] In a gas-blast switch in which the arc is drawn out in a laterally-vented enclosure through which the blast is forced, the vents are so arranged that the gasses are discharged at the outer ends of the vents in at least three different directions when viewed in projection on a plane transverse to the length of the enclosure, whilst the throats at the inner ends of the vents are in alignment with one another and the arc is drawn in close proximity to the throats. The invention may also be combined with that of Specification 517,622. wherein the arc-control device is so arranged that a substantially uniform electrostatic field is produced throughout the enclosure when no current is flowing. Specifications 516,529, 516,530,' 516,531 and 516,532 also are referred to. In Figs. 1 and 2, an insulating structure A has lateral vents E' ... E' extending to the outside from a central space A<2> which is enlarged at A' opposite the vents. The arc is drawn out, against the aligned throats of the vents, between an extended finger B<1> of the fixed-contact structures B and the movable rod contact C, which action may be aided by magnetic or electrodynamo means, as described in certain of the above-mentioned Specifications. The structure A has cylindrical extensions A<5>, A<6> fitting in annular grooves in metal end shields B<2>, C<2> and bolted directly to end plates B', C' by the aid of metal blocks A'. The shields B<2>, C' have each the shape of part of a large-diameter sphere, and are electrically connected to the respective end plates and contacts. An extension C<4> of the shield C<2> forms a cylinder for piston C<1> and has a gas-blast passage C' communicating with supply for opening the switch. The directions of the vents, Fig. 2, are such that the discharges from adjacent ones are as widely separated as possible, and the directions may be equal to the number of vents or limited to three or four in number. The external contour of the structure A is shaped to conform approximately to the electrostatic lines of force between the shields B<2>, C<2> and the curvatures of the vents and of the barriers D between adjacent vents lie along the equipotential surfaces between the shields. Alternatively, radially-arranged barriers as in Fig. 10 may be provided. The blast should be maintained after arc-extinction in order to prevent re-ignition of the arc, and the movable contact should be withdrawn well clear of the enclosure or else an isolating contact should be provided. In Figs. 4 ... 7 (not shown) are illustrated applications of the invention to structures in which the main and isolating switch are mounted on insulators in the open air for connection to overhead lines. Fig. 8 shows another such arrangement wherein the main switch A, B<2>, C<2> is fixed on a pillar F<2> and an isolating break occurs between B<2> and a similar spherical conductor G<2> which is adapted to be swung round by rotation of an insulator F<3> after the main break has been effected. Admission of pressure-gas through H<3> to the cylinder H' depresses the piston H and, by means of links H<4>, rotates a three-armed lever J, J', J<2> about pivot J' whereby the arm. J<2> opens contact C by means of the lever L' and rack-and-pinion mechanism L', L<2>. At the same time the quenching-blast is admitted to structure A through pipe H<5>. The three-armed lever also carries a sector J', the circular edge of which engages a similar surface on the stop K pivoted at K'. At the proper moment in the opening movement, a pin J<5> on arm J' engages a slot K<2> and rotates lever K whereby the lever F<4> and insulator F<3> are rotated and a slide K<4> stops the quenching-blast. In reclosing, the above operations are reversed when gas is admitted through H<2>, the valve K' being opened in readiness for the next breakeropening movement. Figs. 9 and 10 show metalclad switchgear which is vertically removable for isolation purposes. The end-shields B<2> C<2> have generally flat, instead of curved, surfaces, as also the further electrode M<1> into which the contact C is withdrawn, these being housed in an insulating tube M, which is separated from a metal outer casing N by insulating liquid or compound, or by compressed gas or pulverulent mineral insulation. The vents E discharge into compartments formed by the radially-arranged vertical insulating barriers D<1>, the upper end of the tube M being open or provided with a baffle M<3> or discharge outlets in which may be wire gauze or other metal deionizing grids or packings. The main contacts are respectively connected to plug contacts N<3> N<5> carried in insulating bushings. In a modification, Fig. 11 (not shown), the device is horizontally disposed in a generallyhorizontal, cylindrical metal casing and a modified arrangement of the insulating barriers is employed.