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: 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: A pipe coupling comprises a pair of flanges adapted to be secured together in face to face relation to form a fluid-tight coupling. Each flange incorporates at least one coding device formed to provide a key and a keyway, which coding devices are so disposed and arranged on the flanges that the two flanges can only be secured together to form the fluid-tight coupling if the coding devices on the respective flanges correspond with one another, and each of the pair of coding devices comprising, secured within a hole in a flange, a bar member whose cross section is partly cut away to provide the keyway and key, and the bar member being secured in the hole in one of a predetermined number of relative orientations, selectively achieved by adjusting, by rotation, the bar member in the hole.

Abstract: The invention provides a flat glass sight gauge which may have a length ranging up to 4 meters or more and in which a plurality of sight glasses (10) are aligned end to end to give the required length, the glasses being bolted to a frontal face of a structurally stiff metal backing plate (13), the fluid connections required between the aligned glasses (10) being formed at the rear of the backing plate (13), by rigid metal connector blocks (16) which serve also to give structural reinforcement to the backing plate (13) at the ends of the sight glasses (10). This proposal allows for efficient sealing of all the liquid passages of the gauge and for structural integrity of the gauge assembly, enabling it to withstand rough handling, vibration and severe changes of pressure and temperature.

Abstract: The invention provides a valve having a plunger which is moveable towards and away from an annular seat surrounding an inlet port, the seat has, immediately adjacent and surrounding the port, an upstanding annular rim and, immediately surrounding said rim, a flat annular seating surface. The plunger has a nose constituted in part by a flat annular metal portion adpated to be brought into metal-to-metal contact with the flat annular seating surface on the valve seat. On the nose of the plunger immediately within said flat annular metal portion there is formed a recess in which is housed a sealing ring of elastomeric material. When the flat annular portion of the plunger nose is in metal-to-metal contact with the flat annular seating surface of the valve seat, the raised rim of the valve seat enters or is entered into the mouth of the recess and is pressed into resiliently deforming contact with the part of the elastomeric sealing ring which occupies the recess, thus obtaining sealing obturation of the port.