Abstract: A mechanical pump includes a pumping chamber through which extends a pair of parallel shafts 3. Each shaft 3 carries in tandem rotors 4, 5 and 6 at least two of which are the intermeshing "claw" type. The rotors are arranged in complementary pairs and each pair occupies a separate location in the pumping chamber. Each "claw" type rotor 6 of a complementary pair in one location is mounted on its shaft 3 in reverse orientation to the "claw" type rotors 5 of the complementary pairs in the adjacent location.

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: 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 method and an apparatus for dissolving gas in a body of sewage comprising providing a skirt member having a lower open end extending upwardly from said body of sewage to define a volume of said sewage separate from an adjacent body of clarified liquid in said tank, removing a flow of sewage from said body of sewage and pressuring said flow, introducing oxygen into said pressurized flow to form a mixture of oxygen and sewage, introducing said mixture as a jet downwardly into the inlet of a chamber disposed in said volume defined by said skirt member to induce sewage in said chamber and thereby oxygenate said sewage, discharging said oxygenated sewage downwardly through an outlet of said chamber at a reduced velocity, and reducing the momentum of said discharged oxygenated sewage by directing the same onto baffles spaced from the outlet of said chamber.

Abstract: An adaptor for interconnecting a three outlet cutting torch head with a two inlet cutting tip. When installed, the adaptor provides a cavity for mixing combustible gas with heating oxygen. The configuration of the cavity and associated passageways minimizes the possibility of flame blowback into the head.