Abstract: A system for measuring the "time of flight" or transfer time of a sound wave in a gas by using the relation between the gas temperature and the velocity of the sound wave in the gas, and calculating therefrom the temperature of the gas. The system comprises an emitter, which generates a sound which is coherent in phase, at one frequency or a group of frequencies; a self-correlating decoder and a receiver, which is associated with the emitter, and which sends the sound to a filter system and to an assembly controlled by a microprocessor, which processes the signal coming out of the filter system in a shape similar to a Hamming wave shape in order to determine the absolute maximum value and therefrom determine the transfer time. With this knowledge, it is easy to relate the transfer time to the distance traveled between the emitter and receiver and the known properties of the gas, in order to arrive at the temperature of the gas through which the sound has been sent.

Abstract: A combustion gas is cooled a first time to about 110.degree. C. in a first cooling chamber (3), up to 90% of the ashes is removed in a first precipitator (9) then the gas is cooled again in a second cooling chamber (10), to about 80.degree. C.; in a reaction chamber (13), by energization by means of electrons the sulphur dioxide and nitrogen oxides are converted into sulphuric acid and nitric acid and, with the addition of dry ammonia (15) the two said acids are converted to salts of ammonia, the latter are retained in a second precipitator (21) and sent to a chimney; characteristics of the method and the plant are that, from the instant of the injection of the ammonia into the reaction chamber (13), the temperature of the gas is maintained at above 80.degree. C.

Abstract: A method and an apparatus for measuring and controlling the efficiency of a combustion whereby, ash samples are drawn at predetermined time intervals from a region of a combustion plant, each drawn sample is set in an exhausted reaction cell, combustion reaction gas is introduced under controlled pressure, a superficial layer of the sample is heated to the carbon combustion temperature by a CO.sub.2 laser beam, the reaction gas is drawn from the cell and the amount of carbon dioxide produced by the carbon combustion is measured in a calibrated detector. The amount of unburnt carbon contained in the ashes is determined based on a preceding calibration carried out on ashes of known carbon content.

Abstract: A protection system for the basemat of reactor containment buildings in nuclear power stations. The system comprises a structure located in a cavity below the reactor vessel and submerged in water. The structure comprises staggered layers of stainless steel beams for intercepting molten material escaping from the reactor vessel during meltdown of the reactor core. The system is designed so that the molten material is distributed in thin layers over wings of the beams and transfers its heat to the surrounding water thus affording a rapid quenching of the molten core and safeguarding the integrity of the basemat.

Abstract: Improvements in a fuel burner for a boiler comprising a first assembly (S.sub.1) for delivering into the boiler (3) a fuel stream, a second assembly (S.sub.2) for delivering into the boiler a stream of secondary air, a precombustion chamber (6) extended with a certain length (L.sub.2) into the combustion chamber (2) in the boiler (3) and a nozzle flameholder (14), opposite the outlet of the fuel stream, which flameholder supplies fluid jets (F) directed against said fluid stream in order to provide a circulation zone in said precombustion chamber (6); a third assembly (S.sub.3) is provided for delivering into the boiler a tertiary air stream which laps the inner walls of the precombustion chamber (6) and optionally there is provided a fourth assembly (S.sub.5) for delivering a quaternary air stream from outlets (23) of the precombustion chamber (6).

Abstract: A method and an apparatus for determining the dielectric constant of a material wherein the material is loaded to a short-circuited microstrip and microwaves are fed to the microstrip for providing a reflected signal. The reflected signal is compared with a reference signal both under load and not load conditions of the microstrip for obtaining the modulus and the phase of the reflection coefficient, the dielectric constant being a function thereof. The measure of the phase angle between the reference and the reflected signal in both conditions is obtained by handling the reflected signal with a first phase shifter and a second calibrated phase shifter cooperating with a zero detector. The method and the apparatus of the invention is especially designed for a quick and easy measure of the amount of unburnt coal in the ash coming from a combustion heater.

Abstract: The improved atomizer comprises a first and a second mixer for a fuel delivered through a central inlet and for an atomizing fluid delivered through a peripheral inlet, the first mixer including a first mixing chamber whereto the fuel arrives from the central inlet and the atomizing fluid arrives from peripheral ducts, and the second mixer including a second mixing chamber for the fuel and the atomizing fluid that complete their mixing therein and a plurality of outlets for the delivery of the completely atomized fuel to a firebox, the relations among the length, diameter and cross-sectional area of certain parts of the atomizer being defined to impart an effective atomization to the fuel and supply a superior jet of atomized fuel to the firebox.