| 摘要 |
PURPOSE:To accurately control a hydrophonic culture system without analyzing all nutrient liquid component ions, by providing an analytic means to determine NO3<-> ion. CONSTITUTION:The NO3<-> ion concentration of a nutrient liquid in a nutrient liquid tank 1 is determined by an NO3<-> ion detector 5. When the NO3<-> ion concentration in the nutrient liquid is deviated beyond the preset range, the signal is transmitted to a controller 15. The NO3<-> ion concentration of the nutrient liquid in the tank 1 is returned within the preset range by the controller controlling the opening or closure of electromagnetic valves 8, 12 based on the concentration of the stock solution of the nutrient liquid in the stock solution tank 9 and the level of the nutrient liquid in the tank 1 measured by a level gauge 14. The lowering of the level of the nutrient liquid in the tank 1 is detected by the level gauge 14, the controller 15 controls the openings of the electromagnetic valves 8, 12 and the liquid level is returned to the prescribed level to keep the NO3<-> ion concentration of the nutrient liquid in the tank 1 within the prescribed range. |
