Heaters for liquid heating vessels

摘要

A heater for closing an opening in the base of a liquid heating vessel comprises a base plate (2), and in good thermal contact with the base plate (2) a main element (6) for heating liquid in the vessel to a predetermined temperature and a secondary heater of lower power than the first. The secondary heater comprises a resistor (10) in the form of an elongate resistance around an insulating core. The resistor (10) is received in an enclosure (8) mounted to the base plate (2) and filled with a suitably thermally conductive filler material which at least partially encapsulates the resistor (10).