Abstract: A substantially uniform blanket of solid carbon dioxide (i.e., snow) is formed by introducing a plurality of low velocity streams of CO.sub.2 solid and gas generally downwardly into a funnel section which exhibits an increasing, generally rectangular cross-sectional area in the direction of flow of the CO.sub.2 streams. Baffle means are provided in the upper reaches of the funnel section and are effective to initially separate the CO.sub.2 streams introduced into the funnel section from one another and to cause the resulting solid carbon dioxide to fall generally downwardly and uniformly throughout the cross-sectional area of the funnel section to thereby form a substantially uniform blanket of CO.sub.2 snow in a container for products to be refrigerated.

Abstract: A fuel burner 2 for burning a fuel such as pulverized coal carried by a fluid, particularly air, has an inner passage for the particulate fuel-carrier medium and an outer passage for a combustion-supporting gas (typically oxygen-enriched air or pure oxygen). The inner passage typically terminates in a nozzle having an orifice therethrough. The inner passage 12 is surrounded by a jacket containing a pressurized fluid. A pressure sensor senses the pressure in the jacket. In the event that abrasive wear of the inner passage causes holes to be formed therein, fluid will pass from the jacket into the inner passage causing a pressure drop in the jacket which is sensed by the pressure sensor. The burner may then be shut down without any hazard having been caused by contact between the pulverized coal and pure oxygen or oxygen-enriched air. The burner may also be used for the autogenous oxidation or thermal cracking of chemicals.

Abstract: An inert gas stream containing parts per million levels of impurities such as O.sub.2, CO, CO.sub.2, H.sub.2, H.sub.2 O, is purified by passing the same sequentially through a first bed and second bed of material. In the first bed, carbon monoxide and hydrogen are both reacted with oxygen to form CO.sub.2 and H.sub.2 O. The latter is retained in this first bed while the reaction products and the inert gas stream are supplied to a second of material which is comprised of a getter. In this bed, oxygen reacts with the getter material and carbon dioxide is adsorbed therein so that the inert gas stream leaving the second bed is substantially free of such impurities. The first and second beds of material operate at temperatures up to about 38.degree. and these materials may be regenerated by heating the same to approximately 200.degree. C. and purging such beds with a purge gas flow.

Abstract: A compressed gas mixture, for example air, is passed through one of beds 12 and 14 of adsorbent that selectively adsorbs oxygen from the air. Unadsorbed nitrogen-enriched gas flows into a buffer vessel 28, from which product gas is withdrawn through pipeline 30. While one of the beds 12 and 14 is adsorbing oxygen for air the other is being regenerated, and during this period the communication between the beds is denied. At the end of a chosen period of time the beds are placed in communication with one another by opening valves 54 and 56. Then the bed that was previously being regenerated is placed in communication with the source of compressed air and the other bed regenerated. The period of intercommunication between the beds lasts for as long as it takes the volume of product gas as measured by an integrating flow meter 31 from the start of the preceding adsorption step to reach a chosen value. The apparatus is able to supply nitrogen of a chosen purity at a variable flow rate.

Abstract: A vapor component of a gas mixture is separated by condensation and is recovered for further use. A solvent vapor mixed with inert gas is condensed in a multistage heat exchange system in a manner which utilizes a first refrigerant to condense a portion of the vapor in a first heat exchange device, a second refrigerant, typically cold inert gas, for condensing a further portion of the vapor in a second heat exchanger and a third heat exchange device wherein the liquid phase of the inert gas (i.e. cryogenic liquid) is supplied to provide a source of refrigeration. In this latter heat exchange device, the cryogenic liquid is introduced into a body of condensed vapor thereby chilling such condensed vapor and stirring the same to avoid freezing. Chilled, condensed vapor is removed from the latter heat exchange device and is returned as a reflux thereto to condense the vapor component of the gaseous mixture supplied thereto.

Abstract: Methods are disclosed for the purification of mixed gas streams containing hydrogen sulfide, carbon dioxide, carbon monoxide, sulfur, hydrogen, and methane and other hydrocarbon gases, and mixtures thereof, by the use of an oxidizing reactive solid. In one method, the oxidizing reactive solid is, in a first step, contacted with the mixed gas stream which may contain, among other gases, hydrogen sulfide and carbon dioxide. The reactive solid removes the hydrogen sulfide in the form of elemental sulfur with no detectable formation of sulfur oxide. The reactive solid also partially removes the carbon dioxide from the mixed gas stream. In the second step of the first method, the oxidizing reactive solid is regenerated by flowing air. In a second method of the present invention, mixed gas streams, containing hydrogen sulfide and oxygen in an approximate stoichiometric amount, are contacted with the solid, and hydrogen sulfide is converted directly to sulfur with minimal formation of compounds of sulfur.

Abstract: Rod and wire or other ferrous material is annealed, normalized, spherodized, etc. in a furnace under nitrogen based atmospheres to which is added a mixture of methylacetylene and propadiene. This latter mixture reacts with decarburizing substances such as carbon dioxide in the furnace at relatively low temperatures of about 1000.degree.-1100.degree. F. to substantially preclude decarburization of the ferrous material. The use of a mixture of methylacetylene and propadiene in the amount of approximately 0.1-10% by volume of the furnace atmosphere also results in a relatively high CO level, reduces decarburization and oxidation of the ferrous material.

Abstract: A vapor component of a gas mixture is separated by condensation and is recovered for further use. A solvent vapor mixed with inert gas is condensed in a multistage heat exchange system in a manner which utilizes a first refrigerant to condense a portion of the vapor in a first heat exchange device, a second refrigerant, typically cold inert gas, for condensing a further portion of the vapor in a second heat exchanger and a third heat exchange device wherein chilled liquid is utilized to condense a still further portion of the vapor. In a fourth heat exchange device, a cryogenic liquid is passed in heat exchange relation with the liquid passed thereto from the third heat exchange device. The cryogenic liquid is vaporized to form an essentially pure inert gas which is supplied to the vicinity of the oven exit and entrance, but exteriorly of the oven to form inert gas barriers. The fourth heat exchange device may effect direct or indirect heat exchange with the cryogenic liquid.

Abstract: Wood pulp is bleached in a process which includes passing pulp slurry from a chlorine tower through a washer to a downflow extraction tower which is open to the ambient atmosphere. Caustic and steam are supplied to the extraction tower as is dilution water which is introduced into the lower portion thereof. Oxygen is dissolved in the dilution water which may be at least partially comprised of recycled washer filtrate. This addition of oxygen to the dilution zone of an extraction stage enables the consumption of chemicals such as hypochlorite and/or chlorine dioxide to be reduced while still meeting required levels of pulp brightness and strength. Oxygen may be added to the extraction or other alkaline stages of a bleaching process.

Abstract: A continuous heat treatment furnace has an entrance, a preheat zone, a thermal treatment zone, a cooling zone and an exit. Curtains are provided at the entrance and exit respectively. Nitrogen and hydrogen (or other reducing gas) are supplied to the furnace to create a non-oxidizing or reducing atmosphere in the thermal treatment and cooling zones. Elongate workpieces such as tubes are advanced through the furnace and thereby heat treated (e.g. annealed). As the workpieces pass through the curtains so the tendency for air to leak into the furnace is increased. To counteract this tendency, position sensing plates are adapted to actuate a signal generator controlling a valve which in turn controls flow of e.g. nitrogen to the furnace. The arrangement is such that the flow of nitrogen to the furnace is increased wherever a workpiece is sensed, thereby enabling the essentially reducing or non-oxidizing character of the atmosphere to be sustained.

Abstract: A plurality of cords of heat resistant material are disposed adjacent to one another in a plurality of layers. A heat resistant tape material having an adhesive formed thereon in a pair of beads is wrapped around the center portions of the cord members so as to form a pair of free hanging curtain sections effective to block gas flows in a heat treatment furnace or the like. The adhesive is also heat resistant, and the use of a tape to form this curtain assembly enables the same to be independent of mounting hardware such as clamped mounting plates. The vertical position of the curtain assembly may be adjustable so as to compensate for wear during use.

Abstract: Apparatus for providing a gas flow only for a predetermined time period includes a normally pressurized closed valve in a gas line and a timed valve adapted to remove gas pressure from the normally pressurized closed valve thereby opening the same. The length of time during which such pressure is removed is controlled by the period of time necessary to exhaust pressure in a stage of the timed valve through a variable flow restrictor and upon expiration of such time period, pressure is reapplied to the line valve thereby closing the same. The flow of gas is thus permitted to continue for a predetermined time period following which the gas flow is terminated and relatively simple, conventional valve devices may be utilized to reliably control the gas flow.

Abstract: In a pressure swing adsorption process for the production of nitrogen enriched product gas from air, when the process is halted during a pressure equalization step, that is, with valves open to permit the flow of gas from one vessel to a second vessel, then the gas remaining in the vessels is exhausted to atmosphere by opening a further valve. This results in rapid return to the required purity of nitrogen enriched product gas on start-up of the process. Preferably, subsequent to opening the further valve, another valve is opened, thereby permitting nitrogen-rich product gas from a reservoir to flow through the vessels, thereby purging said vessels with nitrogen enriched product gas.

Abstract: A tunnel refrigeration device includes frame members mounted substantially adjacent to an endless conveyor belt which is utilized to pass products to be refrigerated through the tunnel. The frame members are provided with apertures therein and fan means are mounted in one or more of the apertures so as to pass the tunnel atmosphere into the space between the upper and lower runs of the conveyor belt. Apertures are juxtaposed with each frame mounted fan to enable the tunnel atmosphere passed into this space to be removed therefrom and recirculated upwardly in the tunnel by means of the top mounted fans. Refrigeration is provided to the underside of products on the conveyor belt and the effective capacity of the tunnel may be increased by increasing the capacity of the top mounted fans.

Abstract: In a method of freezing a liquid such as cream, a continuous, pulsating stream of liquid is dispensed from nozzles onto a stream of liquified gas flowing along downwardly inclined channels provided by a trough. The liquid forms itself into discrete spheroidal bodies, a substantial number of which have a larger cross-sectional area than that defined by the outlet of each nozzle from which they are dispensed. The bodies are carried by the liquified gas along the channels and at least their peripheries are frozen by the time the bodies reach the downstream end of the channels. Freezing may be completed by gas cooling. The bodies are then separated from the liquified gas.

Abstract: A product such as ground meat is efficiently chilled in a blender device having an open top. Liquid carbon dioxide is introduced into the blender at a location below the surface of the product to thereby form solid and gaseous CO.sub.2. Mixing elements such as a ribbon screw or the like are operated to pass the product in a countercurrent relation to the carbon dioxide introduced into the blender thereby chilling the product and causing the resulting CO.sub.2 gas to rise along one wall of the blender. Deflector means are provided along such wall to direct the rising vapor toward an exhaust plenum located above the open top of the blender.

Abstract: In the manufacture of moulds or mould cores, refractory sand, a resin binder and a catalyst are passed into a mixer to form a freeflowing mixture from which the moulds or mould cores are made. As the sand is fed into the mixer it is cooled by contact with an atmospheric gas in liquid or solid state or the cold vapour of such a gas so as to keep the temperature of the sand as it enters the mixer below that at which the resin cures. To enable the sand to be delivered below a chosen temperature from a quarry to a foundry where the sand is used, the sand after quarrying and drying is fluidized by air, an atmospheric gas in liquid or solid state being introduced into the fluidizing air so as to lower its temperature.

Abstract: A chamber such as a curing oven or drier is inerted during the curing of solvent borne resin coatings with the solvent vapor formed therein being withdrawn together with inert gas at a substantially constant flow rate. The withdrawn gas stream is supplied to a condensation unit to enable recovery of solvent and the noncondensed gas discharged from the condensation unit is returned to the oven at a flow rate which may be varied so as to maintain a material balance with respect to the oven atmosphere. Appropriate adjustments are made in response to changes occurring in the oven solvent vapor and/or oxygen concentration without disturbing the material balance mentioned above while the oven atmosphere is withdrawn at a substantially constant flow rate. A plurality of ovens may be connected to a single condensation unit and upon detecting undesired conditions such as excessive oxygen levels in one oven, the same may be separately isolated from the condensation unit.

Abstract: Tobacco is expanded by cooling the same to a temperature of about 30.degree. F. or less and subjecting such cooled tobacco to a subatmospheric pressure in a vessel. CO.sub.2 gas is then introduced into the vessel and contacts the cooled tobacco to impregnate the tobacco with CO.sub.2 gas as pressure in the vessel is brought to substantially atmospheric pressure. Subsequently, the cooled CO.sub.2 impregnated tobacco is subjected to conditions whereby the CO.sub.2 in the tobacco is removed and the tobacco is expanded. Typically, the CO.sub.2 impregnated tobacco is introduced into an expansion tower wherein it is heated to increase the volume of the CO.sub.2 and to expand the tobacco in size.

Abstract: Sewage is oxygenated and clarified in a tank having an open-bottomed stilling chamber located above an open-topped chamber. Oxygenated sewage is discharged into the stilling chamber where its velocity is reduced, with sewage passing from the stilling chamber into the open-topped chamber being precluded from flowing horizontally along the tank bottom, and upwardly into the clarified sewage.