FIRE HYDRANT DEVICE

PURPOSE:To enable an automatic relief type main value to be opened and closed with the opening and closing of a fire extinguishing nozzle by providing a stem slidable in a valve chamber, the automatic relief type main valve provided on the stem with a valve body and formed on one end side of the stem with a disphragm chamber having a diaphragm fixed and a switch valve in a fire extinguishing nozzle communicating with the disphragm chamber. CONSTITUTION:An automatic relief type main valve 4 is composed of a body 6, bonnet 8 and spring case 9. A valve chamber 11 provided with a spool 10 is disposed in the body 6 to be connected to a fluid inlet 14 and fluid outlet 15. A fire extringuishing nozzle is connected through a hose to the fluid outlet 15. Water jet is stopped by a handle of a switch valve for the fire extriguishing nozzle. Pressure in a diaphragm chambers 12, 13 of the valve chamber 11 exceeds predetermined one, so that a stem 19 is lowered to close the automatic relief valve 5. Then, the hose doesn't have high pressure therein and unnecessary high pressure is not applied on the hose or the like.