| 摘要 |
<p>A radiant electric heater comprises a base (3) of thermal insulation material having supported thereon or adjacent thereto at least two concentrically-arranged heating elements (7, 9) separated by a dividing wall (5) of thermal insulation material to form an outer heating zone (8) and an inner heating zone (6), the heater having a peripheral wall (4) of thermal insulation material. A tunnel (11) formed of thermal insulation material extends between the peripheral wall and the dividing wall across the outer heating zone such that heating element or elements of the outer heating zone are substantially absent from an area occupied by the tunnel. A rod-like temperature-responsive device (10) extends from a periphery of the heater through the tunnel (11) and at least partly across the inner heating zone (6), through an aperture provided in the dividing wall (5). One or more portions of one or more heating elements (7) of the inner heating zone extend into the tunnel. Ventilation means (18, 20, 21, 23, 24) is provided for the tunnel (11) intermediate the ends thereof to reduce temperature within the tunnel to a desired level. <IMAGE></p> |
