| 摘要 |
PURPOSE:To provide the above inexpensive controller capable of proper sprinkling control, so designed as to detect the water content of a culture medium as a level and, based on this value, control the actuation of a sprinkler. CONSTITUTION:In a unit to cultivate plants by feeding a nutrient solution to a culture medium such as of rock wool, sand, peat moss or vermiculite, the bottom of the culture medium 14 is equipped with a water collector 16, while a level-detecting cylinder 20 is set up out of said culture medium 14, and said collector 16 and cylinder 20 are mutually connected through a conduit 18. The level-detecting cylinder 20 is fitted with level detectors (e.g., a pair of electrodes) 22, 24 detecting specified lower and upper limits respectively, and when the lower limit detector 22 detected the lower limit of a level, a sprinkler 28 is started to operate, whereas in case the upper limit detector 24 detected the upper limit of a level, the operation of the sprinkler 28 is stopped. |
