Abstract: A hydraulic actuator for an isolator such as a diverter valve, the actuator comprising a hydraulic ram (1) one end of which is connected to a lever (2) which is in turn connected to a shaft (3) for a valve plate or other closure. The basic novel characteristic of the actuator is that the end of the actuator frame remote from the shaft is connected to the isolator frame by means of a torque arm reaction anchor (4) so as to prevent the actuator from rotating with the shaft.

Abstract: A seal for a gas isolator comprises a cantilever leaf spring (1) attached to a fixed frame or a movable member (2) of the isolator, and a bias spring (3) acting on the leaf spring, and a bar (4) disposed below the seal for clamping and supporting the latter, characterized by at least one additional damping element which will usually comprise a further leaf spring (7), and characterized in that the clamping/support bar (4) is of reduced width.

Abstract: A blade for an isolator, in particular for a diverter or flap isolator, which comprises a plurality of plate arms (21) to be attached to an isolator shaft (31), and a pair of plates (22), preferably comprising an array of panels, attached to the plate arms (21) and separated by a gas space (23). The plates (22) are suitably provided with insulation (27) retained by cladding (28). The blade plates (22) will usually be provided with convolutions (24) to give them improved stiffness, and the blade plates will furthermore be welded or otherwise secured together by fastening means such as a series of short tubes (25) extending therebetween.

Abstract: A hydraulic actuator for an isolator, comprising a casing (1) having a flange (1a) to be mounted to the isolator to be driven, a lever arm assembly (2) connected at each end thereof to a respective one of a pair of identical double acting cylindrical rams (3), the other ends of the rams being respectively connected to opposite ends of the casing remote from the flange, wherein the identical rams are arranged to operate in opposite directions, the radial load exerted by one ram being equal in magnitude but opposite in direction to the radial load exerted by the other ram.

Abstract: A diverter valve (10) provided at a three-way junction through which passes a high temperature gas, the valve having a closure member (12, 13, 14) pivotable between a first position in which it closes a first outlet branch of the junction and a second position in which it closes a second outlet branch of the junction, wherein the closure member carries one or more deflecting vanes (16) positioned (a) in front of the closure member so as to direct the flow of gas into and through the first outlet branch when the closure member closes the second outlet branch and (b) to be hidden behind the closure member and to be isolated from contact with the gas flowing into and through the second outlet branch when the closure member closes the first outlet branch.