Apparatus for raising a liquid to a given temperature

An apparatus for raising a liquid to a given temperature and for controlling and regulating in a constant and accurate manner the temperature to which the liquid has been raised, wherein said apparatus comprises:

• a tight vertical cylindrical enclosure defining a cylindrical wall, including a lower wall and an upper wall;
• a vertical tube located within and spaced from said enclosure, said tube having a sealed base and an upper end connected to said upper wall of said enclosure;
• a heating resistor within said tube;
• a first ferrule concentric to said tube and located between said tube and said enclosure adjacent to said tube, said first ferrule having a free upper portion and a lower portion which is connected to said lower wall of said enclosure;
• a second ferrule concentric to said tube and located between said tube and said enclosure adjacent to said cylindrical wall of said enclosure, said second ferrule having a free lower portion and an upper portion connected to said upper wall of said enclosure;
• said first ferrule and said second ferrule successively defining from said tube and said cylindrical wall of said enclosure a first thin annular space, a second annular space and a third annular space, said second annular space being substantially wider than said first annular space;
• means for rendering the temperature of the liquid homogeneous, said means being located in said third annular space;
• means for supplying the liquid to said first annular space;
• means for extracting the liquid from said third annular space;
• and
• means for controlling and maintaining constant the temperature at which the liquid leaves the apparatus, wherein said apparatus further comprises:
• a plurality of radially distributed orifices formed in said lower portion of said first ferrule separating said first annular space from said second annular space, said means for supplying the liquid to said first annular space being in said lower wall of said enclosure to circulate the liquid upwards in said first annular space, downwards in said second annular space and then upwards in said third annular space, and the length of said resistor being smaller by at least one quarter of the height of said tube, whereby said first annular space, said second annular space, said orifices and said heating resistor form a thermosiphon.