Abstract: A sample removing tool comprises two partly spherical blades which are rotatably mounted on a carrier member about parallel axes. The cutting edges of the blades face each other and a portion of the cutting edges are arranged to lie in a nominal circle. The carrier member is rotatably mounted on a support member about an axis, the axis is perpendicular to a plane containing the nominal circle and passes through the center of the nominal circle. The axes of the blades are inclined to the axis of rotation of the carrier member. The blades are rotated about their axes and the carrier member is rotated about its axis such that the cutting edges of the blades move along the circumference of the nominal circle to cut a sample from a surface of a component arranged perpendicular to and intersecting the nominal circle.

Abstract: A proximity sensing apparatus comprising a capacitor and means for detecting the change in capacitance of the capacitor. The capacitor comprises two capacitive elements that are insulated from each other and are relatively movable. With at least one of the capacitive elements formed from an electrically conducting liquid. The capacitance detecting means operate as a switch in response to the change in capacitance producing a binary output. This output being combined with a series of other outputs from a series of such proximity sensors to form an apparatus to determine position of an object, particularly a liquid level.

Abstract: The effective operating range of an actuator magnet on a position detecting array of solid state hall effect devices improved by the use of flux concentrating elements which direct the flux along the array of sensing devices. The flux concentrating elements comprise a series of rods each avowing a magnetic permeability substantially greater than that of free space, such as soft ferrite, which are placed alignment with and between each sensing device in the array.

Abstract: A chromium nickel silicon stainless steel alloy with improved wear resistance consists of, in weight percent, 19 to 22 chromium, 8.5 to 10.5 nickel, 5.25 to 5.75 silicon, 1.7 to 2.0 carbon, 8.0 to 9.0 niobium, 0.3 to 0.5 titanium and the balance iron plus impurities. The addition of titanium and increased amounts of niobium and silicon alter the microstructure of the stainless steel to form a duplex austenitic/ferritic microstructure which undergoes secondary hardening due to the formation of an iron silicon intermetallic phase.

Abstract: A plate-fin type of heat exchanger (400) facilitates exchange of heat between two process streams (S1, S2) e.g. high pressure methane and seawater. It comprises a matrix (M) of heat exchange plate elements (200') arranged side-by-side, flow passages (401) for the seawater process stream (S2) being defined between adjacent plate elements. The plate elements (200') are a high-integrity diffusion bonded sandwich construction comprising two outer sheets (101, 103--FIG. 3) and a superplastically expanded core sheet structure (102--FIG. 3) between the two outer sheets. The sandwich construction provides flow passages (117') for the methane process stream. Adjacent plate elements (200') are held in position relative to each other by serrated racks (403) which engage the edges of the plate elements.

Abstract: An apparatus for detecting defects comprises a pair of ultrasonic probes which are gimballed onto a pair of elongate members. A pair of yokes are gimballed onto the elongate members. Springs cause an interaction between the yokes and the ultrasonic probes such that the ultrasonic beams travel in a plane parallel to the longitudinal direction of the elongate members. The elongate members are slidably mounted on a carriage and the elongate members are arranged apart at a predetermined angle. The carriage is mounted to travel on an arcuate member to scan the corner of joint between a pressure vessel and a nozzle in a direction radially with respect to the axis of the nozzle. The arcuate member is rotatably mounted to a support member to scan the corner or the joint circumferentially with respect to the axis of the nozzle.

Abstract: Signal generating apparatus comprises a linear series of Hall-effect switches (44) arranged as a plurality of linear arrays in discrete probes (46a, 46b . . . 46n) which are butted end to end. Each switch is closed when in proximity of an actuating magnet (40) moveable along the series of switches. In each array a resistance chain (66) is linked at intervals to the switches. Movement of the magnet along an array thereby gives a progressively changing voltage on an output line (50) from the resistance chain as a cumulative signal indicating the position of the magnet. When the magnet moves from one array to the succeeding array after generating a maximum cumulative signal from said one array, that signal is maintained by a latch connection (56) between the two arrays. A cumulative signal representing the magnet position relative to the complete series of switches can thus be generated.

Abstract: A hydrocarbon fuelled fuel cell power system comprises a fuel cell stack, a reformer and a hydrogen store. The reformer is arranged periodically to supply reformate, which contains hydrogen, to the fuel cell stack and to the hydrogen store. The hydrogen store is arranged to store the hydrogen from the reformate during the periods that the reformer operates. The hydrogen store is arranged to supply hydrogen to the fuel cell stack during periods of low load demands on the fuel cell stack and is capable of supplying hydrogen rapidly to the fuel cell stack for high load demands on the fuel cell stack. The hydrogen store also supplies hydrogen to the reformer to light up the reformer. The hydrogen store buffers the fast response of the fuel cell stack and the relatively slower response of the reformer during relatively large rapid demands on the fuel cell stack and enables the reformer to be operated in an on/off mode.

Abstract: A plate-fin type of heat exchanger (100) facilitates exchange of heat between two or more process streams (101, 102). It comprises a matrix (M) of two different types of heat exchange plate elements (P1, P2) inter-digitated with each other. Adjacent plate elements are metallurgically bonded together for good thermal contact by an activated diffusion bonding process. The plate elements (P1, P2) are high-integrity diffusion bonded sandwich constructions comprising two outer sheets (201, 203 - FIG. 4 and a superplastically expanded core sheet structure (202) between the two outer sheets. The sandwich construction provides flow passages (P) for the process streams. Adjacent plate elements (P1, P2) carry different process streams (101, 102).

Abstract: A fuel cell uses hydrogen as a fuel and oxygen as an oxidant and a hollow member is partially located in an anode chamber, partially located in a cathode chamber and partially located in a water collecting chamber. The hollow member contains a non electrolyte aqueous solution, eg sucrose solution. The hollow member is formed from a semi-permeable membrane which allows water to permeate therethrough but prevents hydrogen, oxygen and the solute, eg sucrose permeating therethrough. Water transported through a solid polymer electrolyte from the anode chamber to the cathode chamber and water produced in the cathode chamber permeates through the semi-permeable membrane into the hollow member by osmosis. Water in the hollow member permeates through the semi-permeable membrane into the anode chamber and dryer regions of the cathode chamber by osmosis. Water in the hollow member permeates through the semi-permeable membrane into the water collecting chamber.

Abstract: An apparatus for locating a source of acoustic emission in a material comprises four spaced transducers coupled to the material. Each transducer produces an output signal corresponding to a detected acoustic emission activity, and each output signal is amplified, rectified and enveloped before being supplied to a processor. Artificially induced acoustic emission events, of known location, are generated in the material. The processor measures the times taken for each output signal corresponding to artificially induced acoustic emission events, to exceed two predetermined amplitudes from a datum time. A neural network analyzes the measured times to exceed the predetermined amplitudes for the output signals corresponding to the artificially induced acoustic emission events and infers the mathematical relationship between values of time and location of acoustic emission event.

Abstract: Apparatus for non-invasively inspecting an object, such as an item of luggage, for explosives material comprises a multi-channel thermal neutron inspection system having a plurality of neutron irradiation chambers. Simultaneous operation of several channels increases maximum system throughout several times. Each chamber has a lithium neutron source which is stimulated to neutron production by a proton beam. Beam switching magnets are energized by pulsing to divert a common proton beam to each source in turn. The initial beam is generated by a radio frequency quadrupole accelerator. The advantages of this system are very low residual source activity and controllable neutron production thereby minimizing safety hazards. The irradiation chamber may contain several different gamma ray detectors to identify the presence elements present in explosives material. In addition a neutron radiography imaging means may be employed to identify the presence of potential shielding materials.

Abstract: A water cooled nuclear reactor comprises a reactor core, a primary water coolant circuit and a pressurizer arranged as an integral unit in a pressure vessel. A passive full pressure emergency core cooling and residual heat removal system is provided which comprises a tank having a reserve supply of water positioned above the primary water coolant circuit or the reactor core. The tank is interconnected to the primary water coolant circuit by a first pipe and a second pipe. The first pipe has an inverted U-bend which passes through a water space and a steam space of the pressurizer to form a vapor lock. The first pipe and second pipe are also provided with hydrostatic thermal seals. The tank has one or more residual heat removal circuits comprising a heat exchanger positioned in the tank and a heat exchanger outside the tank. Movement of the vapor lock from the inverted U-bend allows cool water from the tank to flow into the primary water coolant circuit and hot water to flow into the tank to be cooled.

Abstract: A water cooled nuclear reactor comprises a reactor core, a primary water coolant circuit and a pressuriser arranged as an integral unit in a pressure vessel. The pressure vessel is divided into an upper chamber and a lower chamber by a casing, the reactor core and primary coolant circuit are arranged in the lower chamber and the pressuriser is arranged in the upper chamber. A movable diaphragm is positioned in the upper chamber, and is sealingly secured to the casing by a bellows arrangement to divide the upper chamber into a water filled space and a gas filled space. A plurality of surge ports interconnect the water space with the primary coolant circuit. The diaphragm moves to accommodate changes in the volume or pressure of the water in the primary coolant circuit and water space. The diaphragm is loaded by springs and dampers to prevent oscillation of the diaphragm. Alternatively the diaphragm may be an elastic membrane.

Abstract: A control system for an industrial plant comprises a plurality of instrument sets and a plurality of logic sets.The instrument sets have a number of sensors which detect parameters of the industrial plant, and have two serial link controllers which supply the output signals from each sensor in the instrument set sequentilly to the logic sets.The logic sets have a number of auto select logic circuits, each of which selects data from the sensors from one of the instrument sets, and a synchronister ensures that the output signals from the sensors detecting the same parameter are supplied to a voting logic circuit at the same time. The voting logic circuit performs a voting function on the output signals to produce a series of high reliability signals which are converted to parallel high reliability signals by a series to a parallel converter. The high reliability signals are supplied to a fault logic shutdown circuit which controls the operation of shutdown mechanisms for the industrial plant.

Abstract: A water cooled nuclear reactor comprises a reactor core, a primary water coolant circuit and a pressurizer arranged as an integral unit in a pressure vessel. The pressure vessel is divided into an upper chamber and a lower chamber by a casing, the reactor core and primary coolant circuit are arranged in the lower chamber and the pressuriser is arranged in the upper chamber.A plurality of pipes interconnect a steam space of the pressuriser with an upper portion of the primary coolant circuit via ports in the casing. A plurality of re-entrant surge ports interconnect a water space of the pressuriser with a lower portion of the primary coolant circuit. The surge ports have low flow resistance for water from the water space to the primary coolant circuit and high flow resistance in the opposite direction.

Abstract: In order to reduce any loss of primary water coolant from around a reactor core of a water cooled nuclear reactor caused by any failure of a pressure vessel, an inner vessel is positioned within and spaced from the pressure vessel. The reactor core and main portion of the primary water coolant circuit and a heat exchanger are positioned within the inner vessel to maintain some primary water coolant around the reactorcore and to allow residual decay heat to be removed from the reactor core by the heat exchanger. In a second embodiment an aperture at the upper region of the inner vessel is dimensioned configured and arranged to prevent steam from a steam space of an integral pressurized water cooled nuclear reactor for a ship entering the main portion of the primary water coolant circuit in the inner vessel if the longitudinal axis of the nuclear reactor is displaced from its normal substantially vertical position to an abnormal position at an angle to the vertical direction.