the drains through a main regulating valve sr 13 in the case of an incident a safety regulating valve v 13 enables these condensates to be sent directly to the condenser the reservoir drt also receives the condensates of a drier se not shown through a main regulating valve sr 15 a safety regulating valve v 15 controlled in the same way as the valve sr 15 as a function of the level in the drier enables these condensates to be sent directly to the condenser if necessary the reservoir drt receives the condensates of the heater r 14 a safety regulating valve v 14 controlled by the level regulator r 14 is provided for sending the condensates to the condenser if necessary the contents of the reservoir drt are re injected by way of a condensate withdrawing valve pr in the main circuit cp between the feed pump pa and the heater r 14 through a main regulating valve sr 16 which is controlled by a level regulator rn 13 associated with the reservoir drt this regulator rn 13 also controls a safety regulating valve v 17 whereby the condensates of the reservoir drt may be sent to the condenser the condensates of the heater r 13 are sent either to a phase separator sp 13 through a main regulating valve sr 17 or to the condenser through a safety regulating valve v 17 as a function of the control of the level regulator rn 15 of the heater r 13 the condensates of the heater r 12 are sent either directly to the subheater sor and from there to the condenser through a main regulation valve sr 18 or.