Abstract: The cast metal grill element, which is the subject of this invention, concerns an apparatus for heat exchange between a solid in the divided condition, at high temperature, and a fluid, and comprises a plate of refractory steel, which is apertured with holes therethrough and the upper face of which comprises at least one recessed region, in the bottom of which is a hole in which the leg of a connecting member is engaged, the connecting member securing the grill element to its support. The grill element is for use in particular in cement works, in an apparatus for heat exchange between clinker and air.

Abstract: In a miniaturized delay line constituted by a single crystal through which an ultrasonic beam passes and by two electroacoustic transducers, the direct coupling between the input and the output of the delay line is attenuated by means of a molded shielding element of araldite loaded with silver. The molded element is placed around the output transducer as well as the lead which connects the transducer to one of the connector-pins of the base of the casing containing the delay line.