Edwards Limited

The Boc Group, Inc.

Cambridge Enterprise Limited

Robert Bruce Grant

Ravi Kumar Jain

Andrew James Seeley

Ron C Lee

Barrie Dudley Brewster

David Jonathan Davis

Andrew John Harpham

Paul Alan Stockman

Darren Mennie

Julian Richard Dean

Joanne Rachel Greenwood

Naum Perelman

Neil Condon

William R Gerristead, Jr

Jeremy Daniel McKendrick Watson

Richard Lambert

Georgios Kyriakou

At least one gaseous impurity, for example silane, is removed by absorption from a feed gas stream, for example a gas stream comprising nitrogen and hydrogen, the gaseous impurity being less volatile than the feed gas stream. The absorption is effected by a sub-cooled absorbent at a first cryogenic temperature and a first pressure. The absorbent is typically propane. The absorption may be conducted in a liquid-vapor contact column (). Absorbent containing impurity may be regenerated in a regeneration vesseland returned to the column ().

Purification of a gas stream

Apparatus for treating a gas stream comprises a plurality of cylindrical proton conducting membranes. The gas stream is conveyed through the bore of each cylindrical membrane, and a hydrogen-containing gas is conveyed about the external surface of each cylindrical membrane. A catalyst provided on the inner side of each membrane catalyses a reaction between a halogen-containing component of the gas stream, such as CF, adsorbed on the surface of the catalyst and protons conducted through the membrane.

Apparatus for treating a gas stream

A vacuum pumping arrangement is described for pumping a gas stream containing hydrogen or other hydrogen-containing gas. The arrangement comprises a pumping mechanism for receiving the gas stream and exhausting a pumped gas stream at a sub-atmospheric pressure, and, downstream from the pumping mechanism, an ionic conducting membrane having one side exposed to the pumped gas stream and another side exposed to oxygen or other source of oxygen. In one example, the membrane is permeable to hydrogen, which permeates across the membrane to react with oxygen adsorbed on the other surface of the membrane. In another example, the membrane is permeable to oxygen anions, which permeate across the membrane to react with hydrogen within the gas stream.

Method of pumping gas

A method is described for recycling hydrogen (H2) supplied to a chamber () in a gas stream comprising hydrogen and at least one other gas, such as silane. A gas comprising at least hydrogen is drawn from the chamber () using a first vacuum pump () that exhausts gas therefrom at a sub-atmospheric pressure. A portion of the gas exhausted from the first vacuum pump (), for example between 70 and 95% of this gas, is diverted away from a second vacuum pump () backing the first vacuum pump (). In one embodiment, the diverted portion of the sub-atmospheric pressure gas is treated to produce a purified gas comprising hydrogen, which is stored in a storage vessel (). The composition of the purified gas is analysed, and, depending on the results of the analysis, at least one of hydrogen and silane is added to the stored gas so that the composition of the stored gas is similar to that of the gas initially supplied to the chamber (). Gas is then supplied to the chamber () from the storage vessel ().

Method of recycling hydrogen

A purifier is described for use in a gas processing application. The purifier comprises a chamber having a gas inlet and a gas outlet. A series of baffles are arranged in the chamber and coated with a getter material selected for its ability to react with species to be removed from a gas stream and form stable compounds. The chamber also houses a source of the getter material, which is periodically activated to refresh the coating of getter material on the baffles.

Purifier

An organic contaminant molecule sensor is described for use in a low oxygen concentration monitored environment. The sensor comprises an electrochemical cell, which is formed from a measurement electrode coated with (or formed from) a catalyst having the ability to catalyse the dissociative adsorption of the organic contaminant molecule, the electrode being positioned for exposure to the monitored environment, a reference electrode coated with (or comprised from) a catalyst selected for its ability to catalyse the dissociation of oxygen to oxygen anions, the reference electrode being positioned within a reference environment, and a solid state oxygen anion conductor disposed between and bridging the measurement and reference electrodes, wherein oxygen anion conduction occurs at or above a critical temperature, T. Sealing means are provided for separating the reference environment from the monitored environment. Means are also provided for controlling and monitoring the temperature of the cell, and for controlling the electrical current (I) flowing between the reference and measurement electrodes. At temperatures (T) below T, organic contaminant molecules are adsorbed onto and dissociated at the surface of the measurement electrode leading to the build up of carbonaceous deposits at the surface thereof. At temperatures (T) above T, an electrical current (I) is passed between the reference and measurement electrode thereby to control the number of oxygen anions passing from the reference electrode to the measurement electrode to oxidise the carbonaceous deposits formed at the surface thereof and the formation of carbon dioxide.

Electrochemical sensor

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.

Treatment of effluent gases

A vacuum pumping system comprises a first gas supply for supplying a first gas, such as xenon, to a vacuum chamber. A pump receives the gas output from the chamber. A second gas supply supplies a purge gas, such as nitrogen or helium, for pumping with the first gas. A gas separator receives the pumped gases exhausted by the pump, and recovers the first gas and the purge gas from the stream. The recovered first gas is recirculated through the vacuum chamber, and the recovered second gas is recirculated through at least the pump.

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Steyning, United Kingdom

Robert Bruce Grant