| 摘要 |
PROBLEM TO BE SOLVED: To obtain secure passage of water in next emergency by automatically draining remaining water in a valve casing upper chamber when a valve is opened after completing fire-extinguishing operation or the like. SOLUTION: An inclination valve passage 16 for connecting the inside and outside of a valve casing upper chamber 3 is provided, and a drainage valve 17 is accommodated in the valve passage 16 so that it can be elevated freely. When a ball valve 4 is to be opened on emergency, the drainage valve 17 is raised by the water pressure of water for extinguishing fire flowing inside the valve casing upper chamber 3 for seating at a valve seat 16C. On the other hand, when the ball valve 14 is to be closed after the fire-extinguishing operation is completed, the drainage valve 17 is lowered due to dead weight for opening the valve passage 16, and water remaining in the valve casing upper chamber 3 is automatically drained from a drainage passage 19 to the outside of the fire hydrant.
|
