Abstract: A heat pipe comprising means for regulating the transfer of steam heat. The heat pipe comprises a condenser part, an evaporator part and an interconnecting conduit extending between and joining together said two parts. The regulator means comprises a valve having a valve seat which is fixedly secured to the heat pipe and a valve body of a material having a different coefficient of thermal expansion than the material of the heat pipe. One part of the valve body is fixedly connected to the heat pipe. Another part of the valve body cooperates with the valve seat and together with said valve seat it delimits an opening gap in said valve the size of which varies in dependence of the degree of heating of the heat pipe.