Double-thread sealing device of water pump turbine

The invention relates to the technical field of water pump turbine sealing, in particular to a double-thread sealing device of a water pump turbine. The double-thread sealing device of the water pumpturbine comprises a sealing pipe and a main shaft arranged on the water pump turbine, wherein the main shaft is inserted in the middle of the sealing pipe; a spiral groove is formed in the main shaftinserted into the sealing pipe; a sealing air bag is glued and fixed onto the inner wall of the sealing pipe and contacts the spiral groove in an extruding way; a sealing installation seat is arrangedat one end of the sealing pipe and is arranged on a top cover of the water pump turbine in a sealing way; a drip ring is arranged at the other end of the sealing pipe; a sealing bearing ring is arranged at the other end of the drip ring; and the inner wall of the sealing bearing ring is rotatably arranged on the main shaft through a bearing. Therefore, the leakage of water can be effectively reduced, and stable sealing is