Abstract: Fuel-fired furnace and a method for operating it, in which method: a main oxidizing agent is injected at a controlled flow rate into the combustion chamber of the furnace; the combustible material is burnt in the combustion chamber with the main oxidizing agent, producing thermal energy and flue gases at a temperature higher than 600° C.; the flue gases are removed via an exhaust duct, said removed flue gases possibly containing residual materials that could be oxidized, the exhaust duct being equipped with an inlet for a diluting oxidizing agent downstream of the combustion chamber; the residual materials that could be oxidized are burnt with the diluting oxidizing agent by means of a flame at the inlet for the diluting oxidizing agent; the flame intensity inside the exhaust duct is detected; and the flow rate at which the main oxidizing agent is injected into the combustion chamber is controlled according to the detected flame intensity.

Abstract: The gas-phase fluorination of plastic articles is effected in a reaction chamber 1 into which the plastic articles to be fluorinated are introduced. The gas-phase fluorination is effected at normal or atmospheric ambient pressure of about 1 kPa in the reaction chamber. The gas-phase fluorination can be carried out statically or dynamically. The flushing carried out before the gas-phase fluorination for complete or partial removal of atmospheric oxygen from the reaction chamber 1 can also be effected at atmospheric pressure in the reaction chamber. The reaction chamber 1 is equipped with a cover 2 and metering valves V0, V1, V2 for air, inert gas and gas mixture comprising fluorine and one or more inert gases are present on the entrance side of the reaction chamber, which is not vacuum-tight and hence also cannot be evacuated. The metering valves are connected to the reaction chamber 1 via a flow meter 4.