Abstract: In the centrifugal casting of iron pipes, molten metal from a tilt ladle 13 is supplied to an inclined pour trough or channel 14 whose outlet nose 16 is relatively axially movable within a rotating mold 3. To compensate for the reduction in the hydrostatic thrust of the molten metal in the pour channel when the metal supply is terminated near the end of the casting operation, the inclination of the channel 14 is gradually increased to thereby maintain a constant flow rate at the nose 16. Further, to compensate for the reduction of the height of fall due to the tilting of the pour channel and the attendant lowering of the downwardly sloping nose, the point of articulation 22 of the channel 14 within the mold is also raised in synchronism with the increased tilting of the channel.

Abstract: A fluid-fluid heat exchanger comprises a plurality of flexible synthetic tubes extending in a curved path between a pair of headers with the tubes being maintained in a plurality of spaced apart superimposed layers by a plurality of spaced apart generally radially disposed spacers.

Abstract: A gas cushion vehicle having a portable fan unit with control apparatus for utilizing the air flow generated by the fan for lifting, propulsion and/or inflating a peripheral skirt on the hull thereof such that skirt pressure is higher than cushion pressure and skirt pressure is relatively independent of fan speed.

Abstract: An inductive load driving amplifier is disclosed which includes two serially connected transistors, with Zener diodes limiting the collector-emitter voltage of the one and diverting the collector-base current of the other when the first one switches off. The driver is implemented as an integrated circuit. This collector isolation constitutes a high voltage Zener diode which contributes to limit the collector voltages. The combination of these features prevents the device from being exposed to second breakdown when switching highly inductive loads (e.g. several Henrys under 50V), thereby avoiding the harmful effects of breakdowns during switching.

Abstract: A mechanical coupling for connecting together two buoyant members, such as pontoons, to make a buoyant structure. The mechanical coupling comprises vertical grooves in the pontoons. A pair of spaced apart plates partially cover the edge of the grooves. A key member in the shape of an I-beam fits with its web between the plates of a pair of pontoons so that its flanges hold the two pontoons together. Wedge shaped members attached to the I-beam and to the plates further act to wedge and lock the pontoons together as a unit.