Abstract: A method of measuring the condition of a safety valve includes measuring a condition parameter that varies with the sealing force of the valve. The condition parameter may be determined from in-line measurements, such as measurements of a pressure pso at which the valve will open and a pressure psl at which the valve will leak.

Abstract: A static test rig, for a safety valve having an inlet and a disc movable to open and close the valve, comprises a test table having an aperture therethrough over which the valve can be mounted with its inlet open to the aperture, a gas chamber arranged under the table to admit compressed gas to the aperture thereby to apply a gas pressure to the valve disc, a push rod extending through the gas chamber and arranged to extend through the valve inlet and actuation means arranged to apply an axial push force to the push rod thereby to apply a push force to the disc simultaneously with the gas pressure.

Abstract: A method of measuring the condition of a safety valve comprises measuring a condition parameter that varies with the sealing force of the valve. The condition parameter may be determined from in-line measurements, such as measurements of a pressure pso at which the valve will open and a pressure psl at which the valve will leak.

Abstract: Liquid level indicators include an upright cylindrical tube of non-magnetic material, a cylindrical, permanent first magnet element aligned with and movable coaxially within the tube, a float, and an annular, permanent second magnet element aligned with and movable coaxially outside the tube. The first and second magnet elements have magnetic fields in alignment with one another, with one of the first and second magnet elements being carried by the float. The first and second magnet elements are axially spaced relative to one another such that the one magnet element which is carried by the float supports by magnetic attraction the other magnet element which is not carried by the float.

Abstract: An anchorage appliance comprising a bolt having a head and a threaded stem, a nut on said stem, a metal sleeve permanently associated with the nut and encircling the stem, an annular body of elastomeric material, for example rubber, mounted on the sleeve, a metal collar telescoping over the sleeve. The elastomeric body is subjectible to axial compressive force between annular abutment surfaces on the nut and on the collar when the nut moves up the threaded stem towards the bolt head. The nut, the collar and the elastomeric body when unstressed together have external cylindrical surfaces of similar diameter except that the elastomeric body is formed integrally with at least one narrow outwardly projecting annular flexible flange.