Abstract: A fluid supply system includes a pressure-swing adsorption plant e.g. for supplying oxygen-rich gas to an activated sludge reactor in a sewage works. The product gas from the plant is supplied to the utilization apparatus by a compressor at a rate dependent on the demand for the gas, while waste gas is desorbed from the plant by a vacuum pump. When using the plant to separate oxygen from an air feedstock the major proportion of the power consumed by the plant is represented by the vacuum pump, which has to impell substantially greater volumes of gas than the product compressor. To economize on the power consumed by the plant, the rate of delivery of the vacuum pump is controlled by means sensitive to the demand of the utilization apparatus for product gas, so that a reduction in the demand from the product compressor leads to a reduction in the power consumption of the vacuum pump.

Abstract: Oxygen containing gas is dissolved in sewage passing to, or through, a sewer during periods when sewage is being pumped therethrough. A stream of the sewage is withdrawn during periods when sewage is being held in the sewer. This stream is passed through a conduit so as to promote in such a stream dissolution of oxygen-containing gas introduced into, or entrained in, the stream. The stream is then returned to the sewer. By this means a chosen concentration of dissolved oxygen may be maintained in the volume of sewage between the points of withdrawal and return of the stream.

Abstract: An air separation process using pressure swing adsorption techniques, for providing high purity oxygen. Two sections are employed one comprising beds of molecular sieve carbon and the other comprising beds of zeolite molecular sieve. Air is fed to a first of the sections which provides an oxygen-rich gas stream as feedstock for the next section where further enrichment takes place. The zeolite sieve section serves to effect a separation as between oxygen and nitrogen while the carbon sieve section serves to effect a separation as between oxygen and argon and the processes performed at each section are integrated in such a manner as to minimize power consumption and make use of gas recycled from the second section to the first in addition to the flow of gas from the first section to the second.

Abstract: In a process for condensing the vapor of a volatile liquid, such as vinyl chloride monomer, a gaseous mixture comprising the vapor of the volatile liquid and a non-flammable gas, such as nitrogen, is heat exchanged with a liquid refrigerant or vapor evolved therefrom, or both, the heat exchange being performed such that condensate of the vapor of the volatile liquid is produced at a directly or indirectly controlled temperature which is between the boiling point of the volatile liquid at atmospheric pressure and the boiling point of the refrigerant at atmospheric pressure and which is also between the boiling and freezing points of the volatile liquid at the prevailing pressure at which the condensate is formed, the non-flammable gas remaining uncondensed; the condensate is collected; the uncondensed gas is warmed to a temperature, and then vented to the atmosphere.

Abstract: An improved process for the manufacture of nitric acid involving catalytic oxidation of ammonia and passage of the resulting nitric oxide through columnar absorption zones, the improvement particularly comprising oxygen-enrichment of that gas passing through the absorption zones at one or more regions of the zones wherein the absorption reaction is from 50 to 90% complete. Further, the invention contemplates the oxygen-enrichment of bleaching air and a reduction in the rate at which bleaching air or other air is taken to form secondary air. The invention results in improved production rates of nitric acid and reductions in the concentration of nitrogen oxides in vent gas.

Abstract: A process and apparatus for separating gaseous mixtures by a pressure swing adsorption technique. One or more adsorbent beds are employed which operate on a cycle comprising the successive steps of adsorption, vacuum regeneration, and backfilling. The pressure in the bed(s) during backfilling is sensed, backfilling is ceased when such pressure reaches a predetermined level, and the regeneration step is controlled to occupy a constant period of time. The described process is able to maintain a substantially constant output flow and product purity despite the changes in adsorption capacity of the bed(s) which occur under fluctuating ambient temperatures.

Abstract: The invention relates to a system for treating liquid such as aqueous liquor with a gas that is sparingly soluble therein by introducing the gas into a pressurized stream of the liquid at a sufficient rate to dissolve some of the gas in the stream and additionally to form finely dispersed bubbles of undissolved gas which are carried within the stream. The velocity of the stream is sufficiently high to ensure that the bubbles do not combine to form a discrete vapor phase. The stream is introduced into a volume of the liquid under turbulent conditions so that the bubbles of undissolved gas are broken into even finer bubbles which either dissolve or are consumed in the liquid volume.

Abstract: A method for treating a body of liquid with a gas, which method comprises passing a stream of the liquid through a conduit, injecting gas intermittently into the stream at high pressure so as to dissolve at least some of the gas in the liquid stream, and introducing the stream containing dissolved gas and undissolved bubbles of gas into the main body of liquid under turbulent conditions such that the undissolved bubbles are shattered into even finer bubbles which dissolve in, or are consumed within, the main body of liquid.

Abstract: In underwater arc welding in a chamber filled with gas a consumable flux cored arc welding wire is fed to a welding torch and an arc is struck between the wire and the work to be welded so as to effect transfer of weld metal from the wire to the work. The arc welding wire contains at least one strong deoxidizer selected from the group consisting of magnesium, aluminium, zirconium, titanium, barium, lithium and calcium. A shielding gas is fed to the torch and emerges therefrom as an annular curtain of gas which shields the arc. The shielding gas also helps stabilize the arc from the effects of underwater pressure. The shielding gas comprises at least one oxygen-containing gas selected from oxygen and carbon dioxide.

Abstract: A process for increasing the proportion of a gas in a gaseous mixture of which it is a component. The gaseous mixture is allowed to be drawn through an adsorbent bed in a substantially unpressurized condition by the action of a reduced pressure applied to an outlet of the bed. The bed is then regenerated prior to a further admission of the gaseous mixture thereto.

Abstract: A process for increasing the proportion of a gas in a gaseous mixture comprising such gas and at least two other constituents. The gaseous mixture in a substantially unpressurized condition is drawn successively through two beds of absorbent which adsorbs the two other constituents respectively by the action of a reduced pressure applied to an outlet of the second adsorbent bed in the series. The beds are then regenerated prior to a further admission of gaseous mixture thereto.

Abstract: Apparatus and method for dissolving gas in a body of liquid comprising a gas/liquid contactor device having a plurality of discrete conduit sections of different cross-sectional area connected in series or in parallel.A stream of liquid is passed through the device and gas is introduced into the stream upstream of the device to establish a turbulent gas/liquid contact zone in at least one of the conduit sections.The liquid stream with gas dissolved in it is introduced into the main body of liquid.

Abstract: Method and apparatus for separating gaseous mixtures using adsorbent material. The mixture is contacted with an adsorbent bed which adsorbs preferentially a desired product gas constituent of the mixture. The bed is then purged with such gas or a stream rich in such gas at a pressure substantially equal to the partial pressure of that gas in the gaseous mixture fed to the adsorbent bed. The bed is then regenerated to recover product gas.

Abstract: Laser beam welding apparatus comprising a body with a passage through which the laser beam is directed and focused to a position outside the body closely adjacent to a terminal portion of the passage. A second passage opens into the first to direct a transverse jet of shielding gas to sweep away the plasma formed during welding through an aperture in the opposite wall of the first passage. Since the welding zone is virtually enclosed by the body the incidence of air entrainment by the transverse jet of shielding gas is minimized.

Abstract: A photoelectric follower for following centers or edges of lines to control associated cutting torches produces a sharply-defined edge-of-line signal by making the `black` and `white` level signals of equal amplitude and opposite polarity. The follower has adjustable `lead` and a kerf width adjustment. Line scanning is effected by a piezoelectric rod.

Abstract: Anhydrous metal dithionite compositions are stabilized by 0.1 to 5% by weight of the composition of one or more of vanillin, ethyl vanillin and benzoin.

Abstract: An underwater pipeline is repaired by cutting away a defective section thereof and replacing the defective section with another length of pipe. The replacement is joined to the exposed ends of the pipeline by welded ball-and-socket joints. Those welds that it is necessary to perform under water are made in a gaseous environment created in a chamber having an open base through which water may be displaced by gas and at least one transparent side panel which is displaceable to form a gap in the side of the chamber. A diver may insert a welding gun or welding rod through this gap. The chamber has outer tubular flanges which receive the lengths of pipe extending through the chamber. Tubular members of flexible or elastomeric material are used to seal each flange to the length of pipe passing there through. Each tubular member of flexible or elastomeric material is positioned around the flange and length of pipe which it is to seal.

Abstract: A method of repairing an under water pipeline from which a defective or damaged length of pipe has been cut away to form longitudinally spaced-apart, exposed, pipe ends which method includes the steps of:(a) butt-welding to each exposed pipe end a tubular end portion of a hollow, open-ended member having an inner or outer part-spherical mating surface;(b) butt-welding a sleeve to one end of a length of replacement pipe;(c) mounting on the sleeve a tubular end portion of a hollow open-ended member which has a part-spherical mating surface complementary to that of one of the open-ended members butt-welded to the exposed pipe ends and which is adapted to form therewith a ball-and-socket coupling;(d) welding to the other end of the replacement pipe a tubular end portion of a hollow open-ended member which has a part-spherical mating surface complementary to that of the other of the members butt-welded to the exposed pipe ends and which is adapted to form therewith a ball-and-socket coupling;(e) positioning the re

Abstract: A device for supporting separate parts of a flanged plain bearing so that they can be welded together. The device comprises a main body part having an arcuate seating across its upper surface and a planar side surface adjoining such seating.There are provided means to clamp an arcuate shell in the seating and means to clamp a separate flange against the side surface with the edges of shell and the flange, to be joined together, in abutment and exposed for welding. The latter clamping means includes a clamping element movable to a position in which it engages the face of the flange remote from the side surface to hold it firmly against such surface.

Abstract: A metallic powder and flux-cored arc-welding or hard-surfacing electrode having improved metal deposition rate for gas-shielded arc-welding or hard-surfacing processes is disclosed wherein about 24 to about 35% of the total weight of the electrode is contributed by the core and the core is characterized by a relatively low flux content and high metallic powder content in the order of about 80% or greater, which metallic powder is preferably powdered iron.