Abstract: A compound vacuum pump includes a regenerative section and a Holweck section. An annular abutment is formed on the radially innermost rotating cylinder of the Holweck section. The abutment acts to cause dust and foreign particles entering an inlet of the pump to be trapped before entering an inlet of the regenerative section. A circular barrier may be used with the abutment to assist with trapping the dust and foreign particles.

Abstract: Sour gas containing hydrogen sulphide has hydrogen sulphide absorbed therefrom in an absorbent in a vessel 4. A hydrogen sulphide rich gas stream is formed by desorbing hydrogen sulphide from the absorbent in a vessel 12. The resulting hydrogen sulphide rich gas stream is partially burned in a furnace 32. Resulting sulphur dioxide reacts therein with residual hydrogen sulphide to form sulphur vapor which is extracted in a condenser 44. Residual sulphur dioxide and sulphur vapor are reduced to hydrogen sulphide in catalyst stage 54 of a reactor 50. Water vapor is removed from the resulting reduced gas stream by direct contact with water in a quench tower 60. At least part of the resulting water vapor depleted gas stream is sent to the vessel 4 with the incoming sour gas stream.

Abstract: A method of forming a methane product by rejecting nitrogen from a feed gas stream comprising methane and nitrogen is disclosed. After being cooled in a main heat exchanger, the feed gas stream is rectified in a double rectification column comprising a higher pressure column and a lower pressure column. A gas flow is recycled from the lower pressure column to the higher pressure column. Part of the recycle flow is compressed in a compressor, cooled, liquefied in a condenser-reboiler and introduced into the higher pressure column. Another part of the recycle flow is also compressed in the compressor, cooled, liquefied in the main heat exchanger or by expansion, and introduced into the double rectification column in liquid state. At least part of the cooling of both parts of the recycle gas is performed in the main heat exchanger. A liquid methane product is withdrawn from the lower pressure column.

Abstract: A gas container is made from metal foam and the spaces defined by the open-celled structure are filled with a solid adsorbent material such as a zeolite or an activated carbon. The container may be made in the form of a panel.

Abstract: Nitrogen is rejected from a feed gas stream comprising methane and nitrogen so as to form a methane product. The feed gas stream is cooled in a main heat exchanger and rectified in a double rectification column comprising a higher pressure column, a lower pressure column and a condenser-reboiler placing the higher and lower pressure rectification columns in heat exchange relationship with each other. At least part of the feed gas stream is expanded through a valve into the higher pressure rectification column and the feed gas stream is partially liquefied upstream of the double rectification column. Over a period of time, the mole fraction of nitrogen in the feed gas stream may increase. The operating pressure of the lower pressure rectification column is periodically increased in response to increases in the mole fraction of nitrogen. A back pressure valve may be periodically adjusted to effect the increase in pressure.

Abstract: A gas charging device reversely supplies fresh gas from a gas outlet (7b) of a pressure reducing valve (7) to a gas inlet (7a) thereof. A pressure reducing member (17) of the pressure reducing valve (7) has a communication passage (30) which places the gas outlet (7b) with an actuation chamber (29). The communication passage (30) has a peripheral wall (30a) provided in its end surface with a portion (43) to be sealed, which faces the gas outlet (7b). A charging nozzle (34) has an interior area provided with a charging passage (35) in communication with the gas outlet (7b). A push member (37) is attached to the charging nozzle (34) and is provided with a projection (40) which sticks out toward the pressure reducing member (17). The projection (40) has a sealing means (41). The sealing means (41) is directed from the gas outlet (7b) to the actuation chamber (28) so that it comes into sealing contact with the portion (43) to be sealed.

Abstract: A method for quenching a heated metallic object includes discharging a plurality of discrete gas streams from a plurality of nozzle outlets so that the gas streams impinge substantially uniformly over the outer surface of the object, the distance between each nozzle outlet and the outer surface of the object against which the associated gas stream impinges is less than or equal to half the diameter of the nozzle outlet.

Abstract: A screw pump has two parallel shafts mounted in a pump body, each shaft thereon and each rotor has at least one helical vane or thread. When the helical vanes or threads inter mesh causing a fluid to be pumped from an inlet towards an outlet of the pump. The bearings associated with each shaft are being positioned in cavities within the first and second rotors which are sealed at their ends closest to the pump inlet. A thermal shield is provided between the bearing arrangements and the internal cavity surfaces.

Abstract: A valve assembly comprising a housing having an inlet and space therefrom an outlet, means located in the housing for controlling the flow of fluid between the inlet and the outlet, said means including a main valve movable between a first relatively closed position and a second open position, said movement being controlled by a pilot valve assembly including a temperature sensitive member such that when the temperature in the fluid reaches a predetermined value the pilot valve is opened thereby allowing the main valve to move from said first to said second open position.

Abstract: A method of forming a food product having therein a hydrogenated fat includes contacting a spray of the product in liquid form with a cryogen so as to cool the liquid product and effect a rapid conversion of the liquid product to a solid.

Abstract: A method for the abatement of one or more pyrophoric gases in a gas stream, which includes introducing water in to the gas stream and/or mixing the gas stream with preheated air and introducing the gas stream in to a container in which the pyrophoric gases are abated.

Abstract: A process and apparatus for recovering sulphur from a combustible gas stream comprising hydrogen sulphide, air, commercially pure oxygen or oxygen-enriched air. The combustible gas stream are fed to a burner which fires into an elongate furnace. A longitudinally extending flame is created which as a relatively oxygen-poor endothermic hydrogen sulphide dissociation region, and a relatively oxygen-rich, intense hydrogen sulphide combustion region. Residual hydrogen sulphide reacts with sulphur dioxide formed by the combustion to produce sulphur vapor. The furnace has an aspect ratio of about 8:1. The flame diverges from its root to occupy at its maximum cross-sectional area at least about 80% of the cross-sectional area of the furnace interior coplanar therewith.

Abstract: A feed gas stream containing hydrogen sulphide is subjected in a furnace 6 to reactions in which part of the hydrogen sulphide is burned to form sulphur dioxide, and is which the sulphur dioxide reacts with residual hydrogen sulphide to form sulphur vapor. The sulphur vapor is condensed from the gas stream exiting the furnace 6 in a sulphur condenser 16. Residual sulphur dioxide is reduced back to hydrogen sulphide by hydrogen in a reactor 22. Water vapor is removed from the reduced gas in a quench tower 28 to form a water vapor-depleted gas stream. One part of the water vapor-depleted gas stream is sent to an adsorber vessel 30 in which hydrogen sulphide is absorbed in an absorbent. The resulting hydrogen sulphide-depleted gas stream is vented from the vessel 30 as a purge stream. Another part of the water vapor-depleted gas stream and a hydrogen sulphide-rich gas formed by desorbing hydrogen sulphide from the absorbent in a vessel 38 are returned as recycle streams to the furnace 6.

Abstract: Sulphur is recovered from a first gas stream comprising hydrogen sulphide and at least 50% by volume of ammonia and from a second gas stream comprising hydrogen sulphide but essentially no ammonia, the first gas stream, the second gas stream, and combustion supporting gas comprising at least one stream of essentially pure oxygen or oxygen-enriched air are fed to a single combustion zone or a plurality of combustion zones in parallel with each other without premixing of first gas stream or the second gas stream with oxygen or air, and creating in the or each combustion zone at least one region in which thermal cracking of ammonia takes place, and taking from the reactor an effluent gas stream including sulphur vapor, sulphur dioxide, and hydrogen sulphide, but essentially no residual ammonia.

Abstract: A gas stream containing at least 50% by volume of ammonia but eventually no hydrogen sulphide is burned in a reaction region which is supplied with oxygen and oxygen-enriched air. Both combustion and thermal cracking of ammonia takes place in the reaction region. The rate of supplying oxygen moleculars to the reaction region is from 75 to 98% of the stoichiometric rate required for full combustion of all combustible fluids supplied to the reaction region. Under these conditions essentially no ammonia remains in the effluent gas but formation of oxides of nitrogen can be minimised.

Abstract: A flexible clamp comprising a plurality of plastics links each link being a snap-fit with the next adjacent link thereby permitting a user to alter the length of the chain by the addition or subtraction of one or more links, and means for latching the free ends of the chain together.

Abstract: A vacuum gauge of the cold cathode type has a gauge head which includes a cathode discharge cell and an anode a portion of which is located within the cathode discharge cell. An electrically operated ignition device is located adjacent the cathode discharge cell which ignition device is protected from being operated at high pressure by an auxiliary pressure sensor.

Abstract: A vacuum pump of the scroll-type has a housing, a first fixed scroll member having an end plate and an involute spiral wrap attached thereto and a second orbital scroll member having an end plate and an involute spiral wrap attached thereto. The scroll members are arranged in the housing such that their respective wraps intermesh so that on orbital movement of the second scroll member relative to the first scroll member a volume of gas will be trapped and urged from one end of the wraps to the other end. A shaft for driving the second scroll member and wherein a member is provided which is adapted to separate the vacuum space in the housing from the shaft and also to prevent the second scroll member from rotating the said member being made from a polymer material.

Abstract: Apparatus and method for controlling the composition of the atmosphere within a refrigerated container during the storage and/or transportation of perishable and/or respiring produce in which carbon dioxide and ethylene (and other evolved hydrocarbons) are removed from the container atmosphere by adsorption, the adsorptive materials being regenerated with ambient air.

Abstract: A metal foam object results from the mixing of a gasifier with metal powder and subjecting the mixture to an elevated temperature T1 and pressure P1 to form a sintered sheet placing at least a portion of the sintered sheet into a mold and subjecting the mold to a temperature T2 where T2 is greater than T1 at which the metal melts and the gas is released from the gasifier and quenching the metal foam object thus formed in the mold. The quenching is carried out by applying a cryogen to the object as a high velocity mixture of gas and liquid droplets.