during starting-up periods, i.e. during the periods between the lighting of the furnaces and the attainment of the normal operating temperature of the steam boilers

Full Title

Control systems for steam boilers (for regulating feed-water supply F22D5/00; for controlling superheat temperature F22G5/00) > for steam boilers with natural convection circulation > during starting-up periods, i.e. during the periods between the lighting of the furnaces and the attainment of the normal operating temperature of the steam boilers