| 摘要 |
A heating wire (23) is wound around a housing (1) in which a sensor housing (7) is arranged. Connected to the heating wire (23) is a temperature-sensitive circuit arrangement which responds to the temperature inside the housing (1) in order to control the current intensity of the electric current fed to the heating wire for the purpose of keeping the temperature constant. The housing (1) can be arranged in an airtight further housing (28) which consists of an insulating material. A further heating wire (29) can be arranged on the inner wall of the airtight housing (28). The heating action of this further heating wire (29) is controlled by a further temperature-sensitive circuit arrangement (30, 31), in order to keep the temperature inside the housing (28) at a constant value. <IMAGE> |
