Abstract: A method of refining a ferroalloy includes the step of blowing molecular oxygen or a gas mixture including molecular oxygen into a melt of the ferroalloy. A metallurgically acceptable particulate material is introduced from above into the melt. The particulate material is carried into the melt in a first supersonic gas jet which travels to the melt shrouded by a second gas jet.

Abstract: A method and apparatus for the controlled storage of liquefied gases such as liquefied natural gas in an enclosed insulated container, in which part of the liquid is withdrawn and fed to an external refrigeration unit for subcooling and the subcooled liquid is reintroduced into the container via one or more valve-controlled headers under the control of a control system operated in response to pressure and temperature signals from within the container, wherein the level of subcooling is matched to the heat inleak into the container and most or all of the subcooled liquid is reintroduced directly into the stored liquid so as to maintain stable conditions in the stored liquid and to minimise evaporation thereof.

Abstract: A method is described for treating gas exhaust from a polysilicon etch process, which uses a plasma abatement device to treat the gas. The device comprises a stainless steel gas chamber having a gas inlet for receiving the gas and a gas outlet. As the gas may contain a halocompound and water vapour, the chamber is heated to a temperature that inhibits adsorption of water on the surface within the chamber, thereby inhibiting corrosion of the gas chamber. The gas is then conveyed to the gas chamber for treatment, and the temperature of the chamber is maintained above said temperature during treatment of the gas.

Abstract: A pumping system for evacuating an enclosure comprises a pumping mechanism (30), a motor (32) for driving the pumping mechanism, and a controller (36) for controlling the motor. The controller sets a maximum value for a rotational frequency of the motor and a maximum value for a current in the motor, and, to optimise the performance of the pumping system, independently adjusts the maximum values during evacuation of the enclosure.

Abstract: A method is described of controlling contamination of a surface exposed to a carbonaceous material and ionising radiation, such as EUV radiation, DUV radiation or electrons. The method comprises cyclically supplying to the surface a first gas comprising an oxidising species, for example NO, for reacting with carbonaceous deposits formed on the surface from the carbonaceous material, followed by a second gas comprising a reducing species, for example CO, for reacting with oxidising species on the surface.

Abstract: A microwave plasma reactor (10) comprises a reactor chamber, a microwave resonant cavity (14) located within the reactor chamber, a waveguide (16) for conveying microwave radiation to the resonant cavity, the waveguide having a convergent tapered portion, means for forming an electromagnetic standing wave within the resonant cavity from the microwave radiation for initiating and sustaining a plasma within the resonant cavity, the resonant cavity having a gas inlet and a gas outlet, and conduit means extending from the gas outlet for containing a plasma conveyed from the resonant cavity with a gas flowing from the gas inlet to the gas outlet.

Abstract: A cylinder valve includes: a single valve member in the form of a spring loaded shuttle, the spring exerting a pressure on the shuttle in a valve-closing direction; a valve seat against which the valve member bears in its valve-closing position; a guide defining a channel in which the shuttle is able to travel; a stop member able to be translated in the channel into and out of a position in which the stop member holds the valve member in its valve-closing position; and a valve body which is engaged by the guide, the guide being able to be translated into a position in which the shuttle cannot be brought to bear against the valve seat.

Abstract: A method of introducing a solid particulate reagent into a bath of metallurgical liquid comprises a step of introducing a solid particulate reagent into a main supersonic gas jet. The main supersonic gas jet is directed at the surface of the bath and is surrounded with a jet of shrouding gas, preferably of a burning hydrocarbon fluid fuel, provided at a supersonic velocity. The main supersonic gas jet is formed at a velocity which is in the range of minus 10% to plus 10% of the velocity at which the jet of shrouding gas is formed, preferably in the range of Mach 2 to 3.

Abstract: A freeze dryer shelf with opposed, parallel first and second plates is disclosed. The plates have at least one flow channel located therebetween for conveying a diathermic fluid between the plates. One of the plates has a surface treated to inhibit the sticking to the shelf of a rubber stopper pressed against that surface during the application of pressure to the stopper to push the stopper into a container.

Abstract: A feed gas stream containing hydrogen sulfide is subjected to a Claus reaction in a Claus furnace (16). Oxygen or oxygen-enriched air containing at least 80% by volume oxygen is supplied to the furnace (16) to support combustion of the hydrogen sulfide. Sulfur vapour is condensed out of the resultant effluent gas in a sulfur condenser (3). The sulfur depleted effluent gas is subjected to a plurality of stages of catalytic reaction of hydrogen sulfide in order to form further sulfur vapour in catalytic reactors (36, 44) and (52) with the sulfur vapour being condensed out of the gas in sulfur condensers (38, 46) and (54). The sulfur dioxide content of the resulting tail gas is reduced to hydrogen sulfide in reactor (6).

Abstract: In a method and apparatus for operating and regenerating ion exchange material a wash fluid or elution solution for rinsing the ion exchange material (1) is prepared, there is collected as a by-product of said preparation a first waste stream including cationic species to be eliminated, the ion exchange material (1) is subjected to a wash step in which there is eluted from the ion exchange material by the wash fluid or solution an anionic species to be eliminated and a second waste stream including the anionic species to be eliminated is obtained, the first waste stream (12) and the second waste stream (14) are combined to form a precipitate SW comprising a reaction product of said cationic species and said anionic species, and the precipitate is removed. The method provides an efficient means of eliminating undesired species from a circuit containing an ion exchange material to be regenerated.

Abstract: A Pirani pressure gauge comprises a heated, coiled sensing element formed from an alloy comprising platinum and iridium, for example, 90/10 Pt/Ir. This enables the gauge to be deployed in a corrosive environment and reliably measure pressures as low as 10?4 mbar over a prolonged period of time.

Abstract: An arrangement for installing and sealing an anode within a fluorine generating electrolytic cell is described, the arrangement comprising: an anode connection member, said anode connection member (32) passing through an aperture (70) in a skirt wall (20) and being in electrical connection with a skirt wall closure member (72) wherein the skirt wall closure member is sealingly engaged with said skirt wall and is electrically insulated therefrom.

Abstract: A protector for the head, face and/or eyes, for example a welder's helmet, carries at least one gas sensor in a position where the sensor can detect one or more properties of the atmosphere to be inhaled by a person wearing the protector. The gas sensor is operatively associated with at least one data conversion, data transmission and/or data memory device also carried by the protector.

Abstract: A metallurgical lance for injecting particulate material into a liquid comprises a main gas tube 6 defining an axial main gas passage terminating at its outlet and in a first Laval nozzle 38 downstream of the throat of said nozzle. A shrouding gas passage in the form of a combustion chamber 36 surrounds the main gas tube and terminates in a second Laval nozzle 42. A particulate material transport tube 4 defines a passage for the particulate material to be introduced into the first Laval nozzle 38 downstream of its throat. The first Laval nozzle 38 is provided with a passage 40 for the flow of coolant.

Abstract: Nitrogen is rejected from a pressurized feed gas stream comprising methane and nitrogen by cooling the feed gas stream in a main heat exchanger and rectifying the cooled feed gas stream in a double rectification column comprising a higher pressure rectification column, a lower pressure rectification column, and a condenser-reboiler placing the higher pressure column in heat exchange relationship with the lower pressure column. A pump withdraws a methane product stream from the column. The methane product stream is pressurized by the pump and is vaporized in the main heat exchanger. The pressurized feed gas stream is expanded with the performance of external work in an expansion turbine 6 upstream of the main heat exchanger.

Abstract: A method is described for recovering a noble gas, such as xenon or krypton, from a first gas mixture comprising a plurality of components, one of which is the noble gas and the others are typically helium and/or nitrogen, argon, and relatively light fluorocarbons. The gas mixture is first conveyed to a gas chromatography column for separating the noble gas from the other components of the gas mixture. As the noble gas travels relatively slowly through the column, the other components are exhausted from the column before the relatively slow noble gas. Following the exhaust of these other components, a purge gas is supplied to the column to flush the noble gas therefrom. A second gas mixture comprising the noble gas and the purge gas is conveyed from the column to a membrane separator to separate the second gas mixture into a noble gas-rich gas stream and a purge gas-rich gas stream, which may be recirculated back to the column for re-use.

Abstract: A method of conducting the partial oxidation to sulphur in at least one furnace of part of the hydrogen sulphide content of a feed gas mixture containing from 10 to 60% by volume of hydrogen sulphide but including at least one aromatic hydrocarbon impurity typically selected from benzene, xylene, toluene and ethyl benzene. A flame is created in the furnace. All the feed gas mixture is fed to the flame. Oxygen molecules are also fed to the flame. At last some of the oxygen molecules are supplied from a source of oxygen-enriched air to pure oxygen, and there is created in the flame at least one hot aromatic hydrocarbon impurity destruction region in which a substantial proportion, typically at least 75% by volume, of the aromatic hydrocarbon impurity is destroyed.

Abstract: A rotary liquefied natural gas boil-off compressor has a series of compression stages. A gas passage passes through the series of compression stages. The gas passage extends through and is in heat exchange relationship with cooling means in the form of indirect heat exchangers. Each of the heat exchangers is cooled by LNG supplied from a pipeline. Flow control valves are provided for controlling the flow of LNG to the heat exchangers respectively. The valves are controlled in response to temperature sensors respectively, so as to maintain the inlet temperature of each of the compression stages at a chosen sub-ambient temperature or between chosen sub-ambient temperature limits.