Abstract: In or for a fluid-filled metal-clad switchgear an automatically-operating device for short-circuiting an internal arc in the earthed metal enclosure comprises a piston movable in a cylinder mounted on the enclosure wall, with a rod projecting towards the interior space filled with insulating medium. A pipe or other means connects the space to the cylinder at the remote side of the piston, so that on occurrence of an internal arc in the enclosure the rapid pressure rise creates a pressure differential across the piston to drive it and the rod inwardly and cause the rod to engage the high-voltage conductor and short-circuit the arc to the earthed enclosure. The piston is held normally by a spring or by breakable pegs.

Abstract: Apparatus for use in expanding tubes into holes in tubeplates including walls of drums and headers especially in boilers in which an annular body of elastomeric material is compressed axially and expands radially to force the tube into close engagement with the wall of the hole. The elastomeric material is supported at its ends by radially expansible supports each made up of pieces sliding on adjacent pieces, the sliding surfaces being forced together by the applied force, the pieces being located on reduced diameter end portions of the body. The invention enables applied pressures of the order of 70,000 psi (4830 bar) to be used to stress the tubeplate beyond its elastic limit without damage to the body caused by extrusion.

Abstract: A two-stage method of expanding tubes into holes in tubesplates including walls of drums and headers especially in boilers using an elastomeric body which in a first stage is compressed axially in the tube and which expands radially to expand the tube beyond its elastic limit into close engagement with the hole wall. In a second stage a second elastomeric body of different dimensions is compressed axially to stress the tube and an annular zone of the tubeplate around the tube beyond their elastic limits. Problems of excessive extrusion of and damage to the elastomeric body where tolerances on tube or hole diameter produces excessive clearances are avoided even where high expansion forces are used.

Abstract: A mooring winch system in which automatic mooring duty is performed by a winch having an AC motor fed from the supply via a converter which includes a DC to AC inverter, the convertor producing a balanced three-phase square, quasi-square, sinusoidal or quasi-sinusoidal output. The motor thus can stall indefinitely, be driven in the sense of rope payout by tension force in the mooring rope, or run in the opposite sense to recover rope, without exceeding its rated temperature for that duty. Rope recovery is adequate both for normal duties and also where higher speeds of recovery are required and rope tension is maintained substantially constant throughout.

Abstract: A liquid storage tank made of panels each of which is made typically of glass reinforced plastic material and is generally rectangular and has integral flanges on all four sides. Each corner is relieved. The wall of the panel has at least one stiffening formation integral therewith and typically of dished circular configuration.Auxiliary members are used to complete the tank and occupy positions at the corners of the panels.