Abstract: A system for determining the operability of a valve in active service which provides a user with real time information pertaining to the Safety Margin, the valve torque or thrust, and the percentage of valve MAST that is required for operation. The system employs a combination of an actuator package comprised of a primary actuator, a tandem force module, and a controller operatively connected to the output shaft of the primary actuator, the controller including a processor for calculating the above-described values and providing an output which can be visually, audibly, or electronically observed.

Abstract: A modular actuator assembly which can be used for partial stroke testing of a valve, the assembly having a force module and a tandem piston module. The force module has a primary piston and piston rod interconnected to a shaft which is movably mounted therein. The tandem piston module is connected to the force module and has a tandem piston and piston rod. An indicator plate is connected to the piston rod and is selectively positionable on the tandem piston rod. The tandem piston rod extends into the force module and acts as a pneumatically engaged hard stop for preventing spurious travel of the primary piston and hence spurious valve travel.

Abstract: A sealing assembly, for example a piston ring, for use in harsh environments, e.g., high radiation levels. The piston ring has an annular sealing surface which together with a member forming a radially outer annular cylinder surface, e.g., a cylinder, forms a seal pocket. Received in the seal pocket is an annular seal comprised of a plurality of wraps of at least one strand of a substantially incompressible and inelastic material such as graphite fiber. The assembly further includes a compression ring and compression assembly which compresses the seal body between the support surface and the compression ring to displace the seal body into sealing engagement with the radially inner and outer sealing surfaces.