Abstract: A waste heat boiler has an elongated horizontally oriented gas pass, a steam drum extending lengthwise of the gas pass but wholly outside the same at an elevation near but not above the roof of the gas pass. Transversely extending rows of nested water tubes which are preferably L-shaped with vertical and substantially horizontal stretches have the outer extremities of their substantially horizontal stretches joined to vertical feeder headers that extend upwardly along one side wall of the gas pass, and have the upper extremities of their vertical stretches joined to collecting headers that extend transversely across the gas pass just below its roof. The rows of tubes are arranged in groups or bundles, each held together by distributing headers and receiving headers that are separately connected with the steam drum and to which are respectively joined the feeder headers and the receiving headers.

Abstract: In a flywheel magneto ignition system, opposite terminals of the primary winding are respectively connected with the collector and emitter terminals of a transistor device. A biasing coil, inductively coupled with the magneto armature core, has its terminals respectively connected to the transistor base and emitter terminals to bias the transistor on during an interval terminating at the time of ignition. An SCR, non-conductive during said interval, is connected for short circuiting the biasing coil. A trigger coil, connected with the SCR gate through a zener diode, provides gating current for the SCR at the time of ignition. A diode in series with the biasing coil and the base-emitter junction of the transistor ensures fast transistor turn-off.