Abstract: An oxygen-fuel burner has a pipe 20 for fuel, for example pulverized coal carried in air, and two pipes 22 and 24 for oxygen. The burner is typically mounted horizontally above a burden to be heated. The oxygen pipes 22 and 24 have separate outlets disposed such that the flame is caused to curve towards the burden. The relative rates of supply of oxygen to the two passages are varied so that the flame is moved across at least part of the burden.

Abstract: A gas mixture including sulphur dioxide is recovered from sulphate waste material by burning a fuel to form a flame zone, introducing sulphate waste material into the zone and introducing pure oxygen or other oxygen-rich gas into the flame zone to support combustion of the fuel and to generate a flame of sufficient temperature to crack solid sulphate waste material and thereby liberate sulphur dioxide therefrom. Solids exiting the flame zone are separated from the gaseous combustion products. The sulphate waste material may be taken from a plant for making titanium dioxide pigment by the sulphate route.

Abstract: A compressed gas mixture, particularly air, is separated in absorbent beds 6 and 8 in turn. The adsorbent adsorbs a first component in preference to, or more rapidly than, second and third components. Accordingly, product gas rich in the second component is delivered to the pipeline 44. While one bed adsorbs the first component from compressed gas mixture, the other is regenerated by being placed in communication with the atmosphere through vent pipe 30. At the end of each adsorption step, the respective bed 6 or 8 is placed in communication with a bed 12 of adsorbent that adsorbs the second component more rapidly than, or in preference to, the first and third components, and the pressure between the two beds is equalized. The pressure between the beds 6 and 8 is then equalized. Unadsorbed gas comprising the first and third components is vented from bed 12 to the atmosphere and then the bed 12 is placed in communication with either bed 6 or bed 8 to cause the desired product, i.e.

Abstract: In a distillation column used in the separation of air, a liquid stream of composition intermediate those occuring at the top and bottom is taken from the column and is at least partial reboiled in an external heat exchanger by heat exchange with a heat exchange fluid. The resultant vapor is returned to the column. Its composition matches that of the vapor in the vapor space to which it is returned more closely than that of the vapor in the vapor space above the tray from which the liquid is taken for reboil. The heat exchange fluid is other than one which is taken from a liquid vapor contact column, is passed directly to the heat exchanger, and is then returned directly to the column from which it was taken.

Abstract: A food freezing tunnel has an inner trough member and a roof member. In order to gain access to the interior of the tunnel, for example for purposes of cleaning the tunnel, the inner trough member is able to be raised and lowered. The tunnel has a spray header for liquid nitrogen and fans for circulating resulting cold nitrogen vapor. The tunnel has an inner trough member spaced from the outer trough member. The inner trough member has a floor extending underneath the upper run of a conveyor passing through the tunnel and has sides which prevent direct impingement of liquid nitrogen onto the outer trough member and which co-operate with the roof member to inhibit the passage of cold gas from within the trough member over the sides.

Abstract: A method and apparatus for the separation of air is described. Air is separated in a double distillation column comprising higher and lower pressure columns, an argon-enriched fluid stream is withdrawn from the lower column and separated in a further distillation column provided with liquid argon reflux from a condenser to yield an argon product. Liquid nitrogen is withdrawn from the high pressure column and reboiled in the condenser to form a gaseous stream. At least part of the gaseous stream is warmed and withdrawn. The withdrawn stream may be taken as product or expanded in a turbine to provide refrigeration.

Abstract: A food freezing tunnel has a trough member and a roof member. In order to gain access to the interior of the tunnel, for example for purposes of cleaning the tunnel, the trough member is able to be raised and lowered. Jack means housed in the respective legs of the tunnel are driven by for example an electric motor to lower and raise the tunnel. The trough has counterweights. Typically the jack includes a rotary screw-threaded shaft which carry a nut connected to a chain which travels over pulleys and which is secured to the trough member.

Abstract: An improvement is provided in a process of separating air in a conventional double rectification column to produce oxygen and argon. In accordance with the invention, refrigeration is transfered to the oxygen-rich liquid conventionally formed in the higher pressure column from oxygen-poor liquid formed by condensing the oxygen-poor vapor formed in the higher pressure column. In addition, a portion of the oxygen-poor liquid is vaporized and either withdrawn as product or expanded in a turbine to provide refrigeration in the process.

Abstract: Apparatus for leak testing an article by detecting with a vacuum detector the leakage of search gas through the article, the apparatus including a pumping system predominantly for evacuating the article under test together with an auxiliary pumping system for evacuating a search gas detector responsible to the search gas leaking through the article.

Abstract: A method of preparing a thin film of a semiconductor material on a substrate, in which charged microdroplets of the semiconductor material or a constituent thereof are generated by electrohydrodynamic (EHD) extraction of the droplets from a meniscus forced at an elongate tip of a nozzle containing the material in a molten state, the EHD extraction occurring under the influcence of a high electric field produced by an extractor electrode adjacent the tip of the nozzle. The microdroplets are then accelerated away from the elongate tip of the nozzle to form a two-dimensional ribbon-like beam or blanket of the charged microdroplets. The two-dimensional beam is directed onto the trailing edge of a target carried on a moving substrate such that a film of the semiconductor material is formed on the substrate by deposition of the microdroplets on the trailing edge of the moving target.

Abstract: An incoming stream of gas mixture typically comprising methane and up to 12% by volume of carbon dioxide is subjected to rectification in a first column to form a carbon dioxide depleted fraction that is withdrawn as product from the top of the column and a carbon dioxide-enriched fraction which is withdrawn from the bottom of the column is warmed in a heat exchanger and is introduced into a second rectification column operating at a higher pressure than the first column. A stream in which carbon dioxide predominates is withdrawn from the bottom of the higher pressure column while a stream 34 containing a lower proportion of carbon dioxide than said enriched fraction is withdrawn from the top of the higher pressure column is throttled through a valve and is united with the incoming stream of gas mixture upstream of or in the lower pressure column.

Abstract: A stream of compressed nitrogen (or methane) at above its critical pressure is passed along conduit 10 through heat exchangers 16, 18, 20, 22 and 24, in sequence, to cool it to below its critical temperature. The resulting fluid is then subjected to expansion and resultant liquid is collected. Refrigeration for the heat exchangers is provided by nitrogen working fluid cycles 62, 72 and 82 employing expansion turbines 64, 74 and 84 respectively. The turbines have different inlet temperatures but substantially the same outlet temperature.

Abstract: A distillation tray of the sieve type with a chordal weir or outlet has vapor passages therethrough. The density of vapor passages in the main liquid flow area immediately between the liquid inlet and the liquid outlet of the tray is higher than in the remaining area of the tray so that more vapor flow will be directed into the more active main liquid flow area of the tray, whereby the vapor leaving the tray from the main liquid flow area has substantially the same composition as the vapor leaving the tray from the other area.

Abstract: A heat exchanger has a plurality of main flow passages 2 for cooling fluid. Each main flow passage has associated with it at least one narrow channel 10 defined by a surface of the main flow passage and an auxiliary surface on a separator plate 8. Relatively hot fluid flows over the separator plate 8 and heats the auxiliary surface such that bubbles formed in the channel are flattened by the surface opposite to the auxiliary surface and pressed against the auxiliary surface. The bubbles eventually pass through holes 12 in the channel 10 into the main flow passage 2 to rejoin the evaporating liquid pool.

Abstract: In a process for the separation of argon from air by distillation in a plurality of distillation columns, liquid oxygen and gaseous nitrogen, withdrawn from a distillation column, are introduced into opposing ends of a mixing zone and there are created opposing flows of liquid and vapor that become progressively richer in nitrogen and oxygen, in the direction of flow. A mixed stream containing both oxygen and nitrogen is withdrawn as waste or product from an intermediate point in the mixing zone. The mixing zone also provides for condensation and reintroduction of oxygen-rich vapor and return of liquid nitrogen to the distillation column. The distillation column further provides an intermediate condenser which provides intermediate reboil for the distillation column.

Abstract: Air is fractionated in a double distillation column comprising lower pressure and higher pressure columns. A condenser/reboiler provides reboiled oxygen to the bottom of the column. Liquid nitrogen reflux is introduced into the top of the column. Oxygen, nitrogen and argon-enriched streams are withdrawn from the column. The argon-enriched stream is separated in a further distillation column and a product argon stream is withdrawn therefrom. A liquid stream comprising oxygen and nitrogen is withdrawn from an intermediate level of the column, is at least partially reboiled in a heat exchanger, and is returned to the column at a level where the composition of the vapor corresponds approximately to that of the reboiled liquid. Heating for the heat exchanger is provided by a fluid stream withdrawn from the second distillation column. The fluid stream is returned to the second column.

Abstract: A video camera or other scanning device is employed to monitor the loading with articles to be frozen of an endless belt which passes through a freezing apparatus so as to freeze such articles typically by contact with liquid nitrogen or its cold vapor. The video camera is associated with electronic circuits that generate a signal representative of the belt loading and compare it with a signal representative of an optimum belt loading. If the difference between the signals is greater than a chosen threshold the belt speed is adjusted so as to reduce or eliminate the difference. By this means an improvement is made possible in the efficiency with which the liquid nitrogen is utilized.

Abstract: A liquid-vapor contact apparatus for use in distilling air on board a ship has 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 plurality of spaced, generally horizontal, liquid-vapor contact members each including a horizontal tray member and having edges and in fluid-tight engagement with the respective plates. There are a plurality of downcomers for conducting liquid from tray member to tray member, there being separate flow paths for liquid between each pair of adjacent plates. The two outermost plates form one pair of walls of the apparatus. The other pair walls comprises alternate edge portions of plates and spacer bars (or members).

Abstract: A cryogenerator pumping system comprises at least two cryopanels, maintained within an enclosure having an open end which is adapted for attachment to the chamber to be pumped and which embodies a throttling device effective to restrict the flow of gas from the chamber to the cryogenerator pump, a relatively higher temperature cryopanel within the enclosure being arranged to project beyond the plane of the throttling device whereby to be capable of condensing water and other volatile vapors produced in the chamber and thereby prevent the deposition of such vapors upon the throttling device.

Abstract: Fuel gas (typically taken from a source of natural gas associated with oil deposits) is burnt with air in a turbine 2 to produce a gaseous mixture comprising nitrogen, combustion products and oxygen. The mixture cotnains less than 20% by volume of oxygen. The mixture is cooled in a cooler 4 by heat exchange with water and then compressed in a compressor 6 which is driven by the turbine 2. The compressed gaseous mixture is separated typically by pressure swing adsorption to produce a gaseous nitrogen product suitable for use in the enhanced recovery of oil.