Abstract: Method and device to supply, from a source of alternating voltage (5a or 5b), a thermal printing head (3) comprising a number of heater units (3a, 3b).The device comprises a means (6a to 6d) of obtaining a rectified voltage, a means (8) of detecting the points when the alternating voltage or the rectified voltage change to zero and to produce a detection signal, a means (9) of synchronizing, with this detection signal, the heating of particular heater units and a means (7a, 7b) to absorb current.

Abstract: Chlorine dioxide is manufactured by reducing an alkali metal chlorate in an acid medium by means of a gaseous or liquid reducing agent in at least one production reactor, with recycling of the tail gases to the said reactor, in order to dilute the chloride dioxide produced. In the new process, the tail gases to be recycled are brought into contact with an excess of reducing agent and a sufficient amount of water to reduce virtually all of the chlorine contained in these tail gases to hydrochloric acid, and thereafter the mixture thus obtained, of tail gases after reduction, and of reducing agent, is recycled, at least partly, to the said reactor. In this way, a large amount of chloride ions, which are immediately available for the basic reaction of production of chlorine dioxide, is introduced at the same time as the neutral gases required for dilution.