Abstract: Air is compressed in an arrangement of compressors. A first flow of the thus compressed air flows through a main heat exchanger from its warm end to its cold end and is liquefied by passage through a valve. Two second stream of compressed air are taken. One is expanded in one expansion turbine and the other in another expansion turbine. The streams leaving the valve and the one expansion turbine are separated in a double rectification column. Liquid oxygen product is extracted from outlet thereof. Part is taken as liquid product and the rest is vaporized by passage through the heat exchanger from its cold end to its warm end and taken as gaseous oxygen product. The ratio of liquid oxygen product to total oxygen product is capable of being varied. Accordingly a chosen but variable proportion of the two second air streams flows to the double rectification column and a chosen but variable proportion of the two second air streams is returned to the arrangement of compressors to an intermediate compressor.

Abstract: A system for controlling the atmosphere within a container, including a plurality of adsorption beds for the selective removal on a cyclical basis and in a predetermined order of at least part of any water vapour, ethylene, carbon dioxide and oxygen components present in the atmosphere in an adsorption phase of the cycle mechanism for controlling the flow of atmosphere within the system and mechanism for desorbing the adsorption beds in accordance with a desorption phase of the cycle.

Abstract: An apparatus for controlling the temperature in a building for human or animal occupancy comprises a source of liquid breathable, life-supporting gas consisting of oxygen and nitrogen, dispensing means for dispensing a vaporized mist of the gas within said building. The dispensed mist, being at significantly lower than ambient temperature, acts to cool the atmosphere within the building much more rapidly and effectively than conventional systems.

Abstract: A method of controlling the temperature in an enclosure comprising providing means for dispersing a vaporized cryogenic life-supporting gas within the enclosure to supplement and/or replace a mechanical refrigeration system normally provided therein. The chilling capacity of such a cryogenic system is significantly greater than that available in any presently known mechanical system and hence enhanced overall operation may be achieved. Additionally, the fact that the cryogenic gas is breathable permits an operator to enter the enclosure without presenting any hazard thereto.

Abstract: A vacuum pump assembly which comprises at least two cylinders of different diameters and arranged coaxially relative to each other to define an annular space therebetween and a helical member positioned within the space to define a helical path between the cylinders. Rotation of the cylinders is effected relative to the helical member, or vice versa, about their longitudinal axis.

Abstract: A process of removing carbon dioxide from a liquor in a vessel comprises the step of continuously passing a portion of the liquor into a sidestream and introducing discrete bubbles of between 0.005 mm and 1.0 mm diameter of nitrogen rich gas into the liquor before returning it to the vessel in which the nitrogen acts to adsorb carbon dioxide from the liquor and is then expelled from the liquor as an off-gas. The process also includes introducing a gas to be dissolved in the liquor into the sidestream as discrete bubbles having a diameter of between 0.005 mm and 1.0 mm.

Abstract: A method of storing and transporting acetylene comprises mixing acetylene gas and carbon dioxide gas and then reducing the temperature of the gas mixture thus obtained to obtain either a liquid-vapour or solid-vapour mixture and storing the liquid-vapour mixture or solid-vapour mixture in a pressure vessel.

Abstract: An apparatus for the ectopic treatment of a patient with oxygen comprises a circuit including a bath for receiving the patient, a container spaced from the bath and containing oxygenated liquid and a pump for circulating the oxygenated liquid between the container and the bath. Preferably, the bath is located in a hyperbaric chamber.

Abstract: Simulation apparatus for displaying three-dimensional graphics including a device for emitting an aroma generating material in connection therewith and a dispensing apparatus for emitting the aroma generating material.

Abstract: An apparatus for purifying feed air by adsorption of water vapor and carbon dioxide therefrom includes a purification vessel in which are defined vertically arrange chambers and another purification vessel in which are defined vertically arranged chambers. None of the chambers is in a series flow relationship with any of the others. Each chamber contains a bed of one or more adsorbents which is able to adsorb water vapor and carbon dioxide from the feed air and which forms a reversible part of a gas flow path extending between locations external of the vessels. Valves are associated with the vessel and are operable to permit during a first adsorption period of time simultaneous flows of air to to purified through at least two of the chambers and during a second regeneration period of time simultaneous reverse flows of regeneration gas through the same chambers.

Abstract: An apparatus for dissolving a gas in a liquid employs means for determining the alpha factor of said liquid or a parameter related thereto and control means to control the pumping rate of liquid through the apparatus in response thereto thereby maintaining the gas to liquid flow volume fraction and hence the gas dissolution efficiency within desired limits.

Abstract: A method of machining a blind slot 3 in a workpiece 2 comprises heating the surface of the workpiece 2 above its melting temperature with, for example, a beam of laser energy and directing at least two gas streams 5, 6 such that they together with the base of the slot 3, create a vortex having a predetermined rotational direction for removing molten material from the slot 3.

Abstract: A pressure reduction valve 2 includes a piston 12, a pressure regulating sub-chamber 50 and a movable means, preferably in the form of a second piston 12', which is activated by a filling nozzle 70 to prevent the flow of fluid between an inlet 8 and the regulating sub-chamber 50 thereby to allow the flow of fluid through the valve between an outlet 10 and an inlet 8. This allows a cylinder to be filled whilst the pressure reduction valve 2 is in situ.

Abstract: A container (10) for the storage of perishable foodstuffs is chilled by means of a liquefied gas comprising a mixture of oxygen and nitrogen which when totally vaporised has an oxygen concentration of between 15 and 22%, the remaining concentration being substantially of nitrogen. Such an atmosphere is breathable, and hence avoids the problems associated with non breathable chilling atmospheres.

Abstract: An apparatus for cutting a workpiece comprises optical means located in a single cutting head for splitting a beam of laser energy into two separate beams. The cutting head includes an inlet for oxygen under pressure and a nozzle for the outlet of the oxygen. At least one split beam is focused at a location above the surface of the workpiece such that when in use the area on the surface of the workpiece impinged by the split beam is greater than the area being impinged upon by the oxygen when leaving the nozzle.

Abstract: Simulation apparatus for displaying three-dimensional graphics including a device for emitting an aroma generating material in connection therewith and a dispensing apparatus for emitting the aroma generating material.

Abstract: Air is compressed in a compressor, pre-purified in an unit, and cooled in a heat exchanger. The resulting flow of air is subjected to a first rectification in a double rectification column so as to separate the air into an oxygen-rich fraction and a nitrogen-rich fraction. A further oxygen fraction, enriched in argon, is withdrawn from the double rectification column and is introduced into the bottom of a second rectification column in which relatively pure argon is separated from the oxygen. A stream of relatively impure argon is supplied from an independent source to an intermediate region of the second rectification column through an inlet thereof.

Abstract: A liquid-vapor contact apparatus has pairs of vertical outer walls disposed in the manner of the vertical faces of a cuboid. The apparatus includes a plurality of spaced, parallel, vertical plates. Between each pair of adjacent plates there is a packing comprising a vertical array of corrugated liquid-vapor contact elements of the type that are used in structured packing. The corrugations in each element slope from top to bottom in a direction opposed to that in which the corrugations in contiguous elements slope. The two outermost plates form the walls of the apparatus. The walls comprise alternate edge portions of plates and of spacer bars. The plates define first and second sets of passages, respectively. One set of passages performs a first fractionation duty, and the other set another fractionation duty.

Abstract: A liquid-vapour contact apparatus has pairs of vertical outer walls disposed in the manner of the vertical faces of a cuboid. The apparatus includes a plurality of spaced, parallel, vertical plates. Between each pair of adjacent plates there is a packing comprising a vertical array of corrugated liquid-vapour contact elements of the type that are used in the assembly of structured packing, and having the apexes of the elements in fluid tight engagement with the respective plates. The corrugations in each element slope from top to bottom in a direction opposed to that in which the corrugations in contiguous elements slope. The two outermost walls form the walls of the apparatus. The other walls comprise alternate edge portions of plates and of spacer bars. Liquid is distributed appreciably evenly between the passages formed by adjacent vertical plates at the top of the apparatus and flows over the elements and effectively vertically downwards.

Abstract: Cooled and purified air is introduced into a higher pressure rectification column and separated into oxygen-enriched liquid and nitrogen vapour. A stream of the oxygen-enriched liquid is flashed through a pressure reducing valve to form a mixture of liquid further enriched in oxygen and vapour depleted of oxygen. The liquid is reboiled by reboiler. A stream of the further enriched liquid is reboiled in condenser and is introduced into a lower pressure rectification column for separation into oxygen and nitrogen products. Reflux for the columns and is formed by condensing in condenser nitrogen vapour separated in the higher pressure rectification column. A reboiler provides an upward flow of vapour through the column. The condenser and reboiler take the form of a single heat exchanger. The reboiler is located in a phase separator, the reboiler is located in a rectification column containing liquid-vapour contact devices above the level at which fluid issuing from the valve is introduced.