To provide a small and highly reliable flush valve by solving the problem of generating a malodor from the inside of a trap, without completely replacing water in the trap of a urinal.
This operation valve for the flush valve has a main valve, a valve port for communicating a pressure chamber and the secondary side for opening the main valve by releasing hydraulic pressure in the pressure chamber for pressing the main valve in the valve closing direction, and a pilot valve for opening-closing the valve port. A cylinder chamber is arranged in a pressure chamber communicating passage communicating with the secondary side from the pressure chamber of the flush valve, and a piston freely sliding in the cylinder chamber is arranged in the cylinder chamber. The inside of the piston is provided with the pilot valve for opening-closing the valve port, a pilot valve seat, and a first energizing means for pressing the pilot valve to the pilot valve seat. A valve rod for transmitting operation force to the pilot valve and the piston, is oppositely arranged to the pilot valve. A second energizing means is arranged for energizing the piston in the direction of the valve rod.
TOYOSHIGE TAISUKE
FURUI NAOKO
MATSUFUJI YOSHINAGA
