operating with superimposed recirculation during starting and low-load periods, e.g. composite boilers

Full Title

Steam boilers of forced-flow type > of once-through type, i.e. built-up from tubes receiving water at one end and delivering superheated steam at the other end of the tubes (combined low- and high-pressure boilers of forced-flow type F22B33/16) > operating with superimposed recirculation during starting and low-load periods, e.g. composite boilers