PROBLEM TO BE SOLVED: To provide a nutrient solution-circulating sterilization apparatus 2 in which carbon dioxide is supplied required for a room cultivation to suppress decrement thereof to eliminate the need of separately purchasing/supplying carbon dioxide to reduce the running cost, and a constant-temperature tank 43 is arranged so that combustion continuation time of a gas heating device 42 is prolonged to stably supply carbon dioxide, nutrient solution-circulating sterilization is surely performed, and a whole apparatus can be miniaturized to be manufactured at a low cost.SOLUTION: A nutrient solution-circulating sterilization apparatus 2 comprises: a main body tank 41 with a heat sterilization device 4 including a helix tube body 412 for a coil type heat exchange and a constant-temperature tank 43 where nutrient solution is accumulated and flowed during sterilization to be a constant temperature and a gas heating device 42 by which hot water in the tank is heated. Heat exchange is performed through a heat exchanger 3 between the used and unsterilized nutrient solution transmitted from the cultivation bed 11 and the sterilized nutrient solution heated/sterilized at the heat sterilization device 4 to transmit the sterilized nutrient solution to the cultivation bed 11.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2016,JPO&INPIT【課題】 室内栽培に必要な二酸化炭素を供給してその減少を抑制し、別途二酸化炭素を購入供給する必要性を少なくし、ランニングコストの低減化を図ると共に、定温化タンク43を経由することで、ガス加熱器42による燃焼継続時間を長くして二酸化炭素を安定供給し、かつ養液の確実な循環殺菌が行え、しかも、装置全体が小型化され安価に製作できる養液循環殺菌装置2を提供する。【解決手段】 加熱殺菌装置4を、その内部にコイル式熱交換用の螺旋管体412と殺菌中養液を蓄積流動して定温化する定温化タンク43とが設けられた加熱殺菌装置4を備える本体タンク41と、該タンク内湯煎水を加熱するガス加熱器42とで構成し、栽培ベッド11から送られる使用済み未殺菌養液と、加熱殺菌装置4で加熱殺菌された殺菌済み養液とを、熱交換器3を介して熱交換を行なって栽培ベッド11へ送出する。【選択図】 図1
