AUTOMATIC AIR FEEDING DEVICE FOR SUCTION PIPE OF HYDRAULIC TURBINE

PURPOSE:To make it possible to feed air into an air suction pipe even when an air feeding valve fails by connecting a bypass pipe line provided with the air feeding valve feeding air into the suction pipe of a hydraulic turbine. CONSTITUTION:An air feeding pipe line 2 is connected with the suction pipe of a hydraulic turbine 1, and an air feeding valve 3 connected with an air feeding valve opening detection device 4 is arranged at midway of the air feeding pipe line 2. In addition, a bypass pipe line 10 going around the air feeding valve 3 is connected with the air feeding pipe line 2, and the same pipe line 10 is also provided with an automatic valve 11. Then, a comparison operating device 8 allows each opening signal from the air feeding valve opening detection device 4 and from a guide vane opening detection device 7 to be compared with a set signal so as to be operated by an air feeding valve opening setting device 9 so that an opening command signal is generated. The opening command signal is controlled in such a way that the automatic valve 11 is fully opened based on judgment that the air feeding valve 3 and the like have failed when the opening command signal is less than that for the optimum opening of the air feeding valve 3 set for every opening of a guide vane 6.