| 摘要 |
Apparatus for applying heat and cold to a tooth to determine if the nerves in the pulp of the tooth are alive. The apparatus includes a housing; a thermoelectric module carried in the housing including a plurality of semiconductor elements connected at their ends by a pair of opposed groups of electrically conductive plates to form an electrical series of the semiconductor elements, each of the pair of plate groups constituting hot junctions when electrical current passes through the series in one direction and constituting cold junctions when electrical current passes through the series in the reverse direction; a primary heat transfer member in thermally conductive contact with one of the pair of plate groups; a secondary heat transfer member in thermally conductive contact with the other of the pair of plate groups, the secondary heat transfer member including a thermally conductive casing, and passage means formed within the casing to receive and carry fluid therethrough and including at least one inlet and one outlet opening; conduits for directing fluid into the inlet opening of the passage means and for receiving fluid flowing through the outlet opening; terminals for making electrical contact with the thermoelectric module; a source of current electrically connected to the terminals; normally closed switch means connected between the terminals and the current source; and, a thermocouple unit in thermal contact with said primary heat transfer member for measuring the temperature of the primary heat transfer and for causing the switch means to open when the temperature of the primary heat transfer member reaches a preselected level.
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