an apparatus which is heated by a gasified liquid fuel has between the liquid fuel reservoir and a burner , a flow regulator / evaporator consisting of two porous masses separated by a recondensation chamber , the valve for cutting off the combustion being provided between the burner and the downstream mass . liquid fuel can accumulate in the recondensation chamber so that , for startup of the system , there is an increased flow of fuel through the downstream porous mass to the burner to allow rapid heat up of the heat - distributing member . after the initial heating period the flow to the burner is determined by the porosity characteristics of both masses in series .