PURPOSE: To exhaust compressed air quickly and surely at returning from water level depressing operation to ordinary operation.
CONSTITUTION: A main shaft 21 is provided with an air charge/discharge hole 37 communicating a high pressure stage part runner flow passage 39 and a low pressure stage part runner flow passage 40 to each other. An upper exhaust hole 38b communicating to a back pressure space 36 is provided on the high pressure stage part runner 22. A lower exhaust hole 38a which communicates to the upper exhaust hole 38b and also to the low pressure stage part runner flow passage 40 is provided. Onto the way of a returning flow passage 30 from the outlet in the direction of the high pressure stage part water turbine to the inlet of a low pressure stage part guide vane 33, a water feed piping 43 to feed high pressure water higher than the suction head of the low pressure stage part, and an air feed piping 44 are connected.
SHIRAKI KIYOTAKA
UMEDA SADAICHI
KUROKAWA TOSHIFUMI
UTO YUETSU
YAMAGATA ICHIRO
KONNO TOSHIRO
TOSHIBA CORP