Abstract: With a rotary nozzle of the type in which a slide plate brick having at least one nozzle bore is rotated so as to adjust the degree of overlapping between the nozzle bore thereof and a nozzle bore of a fixed plate brick to control the rate of pouring of molten steel or the like, the bricks constituting the fixed plate brick and the slide plate brick are formed into the most rational and economical shape for the purpose of seeking a reduction in their cost and also the bricks are used for the purpose of seeking a reduction in the running cost of the rotary nozzle. To achieve these purposes, the shape of the brick 40 is formed into a substantially elliptic shape and nozzle bores 41a and 41b are provided in the respective eccentric positions.

Abstract: A glow plug for diesel engines includes a ceramic heater with a U-shaped heating portion and a pair of leads integrally formed with the heating portion and extending backwards from both ends of the heating portion. The heater is supported at one end thereof by a hollow holder in a cantilevered state with one end thereof protruding towards the outside. At least the outside surfaces of the leads are joined to, and held by, the inside of the holder via an insulating layer, and at least the rear ends of the other of the leads are connected via a metallic lead wire to an external connection terminal supported in an insulated state by the rear end of the holder. The ceramic heater is integrally formed from an electrically resistive sintered sialon produced by adding 20-70 vol. % Ti nitride or carbonitride as an electric conductivity donor to .beta.-type sialon or a .alpha./.beta.-type sialon.