Abstract: An alarm for a hydraulic system, a hydraulic system incorporating an alarm, a vehicle having a hydraulic system which incorporates an alarm, and a method of giving an alarm in a hydraulic system, where the hydraulic system comprises hydraulic fluid which is put in contact with a pressure detector, the pressure detector being for giving a signal in response to a condition of the hydraulic fluid in the hydraulic system. An alarm generator integral with said pressure detector is provided for giving an audible alarm in response to a said signal.

Abstract: A closure apparatus comprises a collar 2 having a collar periphery and having a collar inner surface defining an opening 3, a closure 10, having a closure periphery, said closure 10 being for closing said opening 3, a bearing structure 7 being located around said collar periphery or said closure periphery, a locking ring 18 being mounted for rotation with respect to said closure 10 and said opening 3 on said bearing structure 7, so that said locking ring 18 is rotatable between a locking position for locking said closure 10 to said opening 3 and an unlocked position for permitting said closure 10 to be moved away from said opening 3.

Abstract: A closure arrangement comprises a hub 314, a head 320 adapted to be disengage able from the hub 314. A davit arm 300 is mounted on a swivel mount 316 provided on the hub 314, and the swivel mount 316 is arranged to allow the davit arm 300 to swivel in a plane. The davit arm is free to move in a longitudinal direction in the plane, and to rotate about the longitudinal direction. The closure arrangement is further provided with an adjustment device adapted to adjust the position of the head 320 relative to the hub 314 in a direction perpendicular to the plane.

Abstract: A guide plate for a lug type closure arrangement is provided with a stepped profile to aid a user move the head of the closure arrangement relative to the hub from a locked to an unlocked position. A marker pin is provided to align with the guide plate at various stages in the unlocking sequence. The relative positions of the marker pin and the guide plate indicate to the user the relative positions of the lugs on the head and the lugs on the hub.

Abstract: A system and method is provided for locking a lug-type rotary closure assembly in a closed position. The locking arrangement includes a pressure warning device, which may also release internal pressure. The system cannot be unlocked and hence the closure cannot be opened, until the pressure warning device has been moved to a position where it will warn of internal pressure and/or release internal pressure.

Abstract: A piston pig for pushing pigs from a larger diameter conduit into a smaller diameter conduit, where one embodiment includes a cylindrical body with a first sealing disc attached to the body and adapted to seal against the larger diameter conduit and maintain a pressure differential across the body of the piston pig. The piston pig also includes a second sealing disc attached to the body and capable of sealing against the smaller diameter conduit and maintain a pressure differential across the body. Certain embodiments also include a pressure control device, such as a resilient flapper disc, to limit the differential pressure across the body. Some piston pig embodiments may also include an end cap attached to, and slidable relative to, the body, where the end cap has a closed position in which fluid cannot bypass the end cap and an open position in which fluid can bypass the end cap.

Abstract: A system for storing pigs and launching them into a pipeline comprises a pig storage barrel having an inlet end and an outlet end and an inside diameter sized to accommodate the pigs, the storage barrel including a pig parking chamber for controlling release of the pigs, and a pig launching chamber downstream of the storage barrel. The launching chamber is connected to the pipeline so as to be able to launch a pig into the pipeline. The apparatus also includes a hydraulic pig advancing system in fluid communication with the storage barrel and the launching chamber and a fluid flush system in fluid communication with the storage barrel chamber and the launching chamber. The method includes flushing the storage barrel and the launching chamber after each launching cycle so that between launchings the system is filled with hydraulic fluid.