| 摘要 |
PURPOSE:To simplify the structure of a bottom heater by serving once of water catching boxes to connect a rubble layer to pumping up pits as a pouring box for hot water from the pumping up pits, and the other water catching boxes as the pouring box for water from the rubble layer. CONSTITUTION:Water catching boxes 13a-13d are provided on the periphery of a rubble layer 12, and communicates with pumping up pits 17a-17d. The rubble layer 12 and the pumping up pits 17a-17d are arranged so as to form water level difference by which hot water is led from water catching pipes 18a-18d into the ruble layer 12 through the water catching boxes 13a-13d, when the fixed quantity of the hot water has been stored in the pumping up 17a-17d. Consequently, a bottom heater can almost uniformly supply the not water keeping the fixed water level difference in the rubble layer 12 to effectively warm the bottom of a tank. |
