Apparatus for preventing backflow of fill valve in water toilet

An apparatus for preventing a backflow of a fill valve in a water toilet, comprising:

• a fill valve for permitting and stopping supply of washing water from a hydrant into a water tank;
• a fixing section fixing the fill valve to an overflow pipe;
• a float having a packing for opening or closing an opening/closing hole of the fill valve depending on a level of water contained in the water tank;
• and
• a backflow-preventing section disposed inside the fill valve, wherein the backflow-preventing section permits washing water, which is being supplied from the hydrant, to be supplied into the water tank, and prevents washing water inside the water tank from flowing back into the hydrant when washing water flows back,
• wherein the backflow-preventing section includes:
• a backflow-preventing member mounted to a supply pipe of the fill valve;
• and
• an operation control member seated on a fitting protrusion of the fill valve to control an operation of the backflow-preventing member;
• and
• wherein the fill valve comprises:
• a valve body, which has the supply pipe communicating with a hydrant, and which has a water tank-side water supply pipe and a rim-side water supply pipe extending through opposite ends thereof;
• an air passage hole formed in a bottom of the valve body;
• a water supply valve, which opens or closes the supply pipe;
• a support member disposed inside the valve body to support the water supply valve;
• a cap pressing the support member and the water supply valve, wherein the cap has an opening/closing hole formed therein;
• a fastening nut fixedly fastened to the valve body, wherein the cap is received inside the fastening nut.