Abstract:
In a railway line, thermally-induced stresses are a factor for both rail breaks and rail buckling. These stresses are in the longitudinal direction. A nondestructive measuring technique enables the residual stress in a rail to be determined, and hence the thermally-induced stress. An electromagnetic probe is used to measure the stresses in the rail web in the vertical direction, and in the direction parallel to the longitudinal axis. The residual stress in the longitudinal direction can be deduced from the measured stress in the vertical direction; hence the thermally-induced stress can be determined.
Abstract:
A fire suppressant powder with particle sizes less than 5 .mu.m is made by a chemical reaction between a gas or vapour of a first material and a vapour or an aerosol of a second material. For example an aerosol of sodium hydroxide droplets may be reacted with carbon dioxide gas to produce sodium bicarbonate powder; or boron halide vapour may be reacted with steam to form boric acid powder The powder may be used in fire extinguishers either on its own, or combined with other ingredients such as silica and/or alumina, and calcium stearate.
Abstract:
Corrosion, scale-formation, or other deleterious processes are inhibited in an oil well by installing within the oil well (10) fluid-permeable elements, such as tubular filters (20), which comprises a suppressing material. Each filter (20) comprises two tubular filter screens (24) between which is a bed (26) of particles comprising suitable inhibitor material. The particles might for example be porous ceramic spheres impregnated with the inhibitor material. The inhibitor material gradually dissolves in the well fluids during operation, and may for example inhibit corrosion and/or scale formation.
Abstract:
A mass-analysed ion beam generator in which the ion beam is in the form of a thin flat ribbon with its major transverse dimension aligned parallel with the direction of the mass-analysing magnetic field.
Abstract:
A double lid system is provided with an electric motor (44) to actuate mechanisms to release the lid (20) from a drum (18) and simultaneously clamp the lid (20) to a door (14) of a port (or vice versa), and with an electric motor (74) to withdraw the door (14) from the port to open the port (or to close it). The system is monitored by sensors (60,62,64,82) associated with an electronic logic interlock to ensure the correct sequence of operations of the motors (44,74). The sensors (60,62,64,82) and the motors (44,74) are readily demountable for remote maintenance or replacement. The door-opening motor (74) may he a linear actuator cooperating with a part-helical slot (80) to open the door (14) and then swing it clear of the port.
Abstract:
The absolute values of biaxial stresses in a ferromagnetic material (16) are measured using a probe (12) which comprises an electromagnet (26), a sensor (32) for stress-induced magnetic anisotropy (SMA) and a sensor (30) for directional effective permeability (DEP). The DEP sensor (30) enables absolute values of stress to be determined; the SMA sensor (32) enables the directions of the principal stress axes to be accurately determined, and improves the accuracy of the stress measurements.
Abstract:
A plate (12) or pipe wall is inspected by coupling an ultrasonic transducer (14, 16) to its surface so as to generate a compression wave or lateral wave (26) along the surface and a shear wave or head wave (28) along the surface and a shear wave or head wave (28) at the shear-compression critical angle (.theta..sub.c) The same transducer (14, 16), or an additional transducer (15, 16) also coupled to the surface, detects a series of ultrasonic peaks corresponding to each generated ultrasonic pulse. Each such detected peak corresponds to ultrasonic energy traveling, partly as lateral waves (26, 32) on one surface or the other, and partly as head waves (28, 30) crossing a certain number of times between the surfaces. The transducers (14, 15) may be over 0.5 m apart, and substantially all the intervening parts of the plate (12) are inspected.
Abstract:
In a magnetically insulated line oscillator device having a cathode 11, a surrounding slow wave structure 15 has a tapered configuration so that the effective cavity depth in the slow wave structure 15 progressively diminishes along a part of the length of the device towards the power output end of the device.
Abstract:
A filter which can be cleaned in situ consists of a filter membrane (33), and fluid permeable electrodes (34, 35). The membrane may be one of the electrodes, or may be electrically non-conducting but integral with or in contact with one of the electrodes (34). The electrodes (34, 35) are separated from each other only by a fluid permeable electrically insulating sheet. This sheet may be less than 1 mm thick, and may be the filter membrane (33). The filter is cleaned by periodic brief applications of electric current between the electrodes (34, 35) so that gas is generated electrolytically, and the close spacing of the electrodes (34, 35) reduces the electric power required.
Abstract:
A liquid metal electromagnetic pump 17 operates by passing an electric current through the liquid metal in a direction transverse to an applied magnetic field and the longitudinal axis of the liquid metal flow pipe. The direction of the pump is reversible by reversing the electric current. It is used to transfer batches of contaminated solder from a reservoir 12 in a hot air solder leveller 11 to a treatment tank (TA or TB). Contamination of the solder is removed by a cleaning process and the liquid solder returned to the reservoir 12 after heating to the required process temperature.