| 摘要 |
PURPOSE:To prevent outdoor piping from freezing, by providing valves which can feed water into a water heater in the normal operating conditions, and can drain water from the piping for the time when freezing is anticipated. CONSTITUTION:When an indoor feedwater valve 22 is opened to start feeding, the fed water rising upward through a feedwater pipe, filling a cistern 3 with water, is fed into a storage tank 1 from a needle valve seat 17. When a float 19 is gradually floated upward to reach the normal highest water level, the needle valve seat 17 is closed by a needle valve 18 which stops feeding of water. When freeze is anticipated, the feedwater valve 22 is closed and a drainage valve 23 is opened, then the air is penetrated from the needle valve seat 17 to drop the water down through a feedwater pipe 2, and next, the water in the cistern 3 is also drained, being displaced with air. Then a volumetric body 4 that is a floater loses its buoyancy, falling down due to its own weight, at the same time an outer lever arm 7 is moved to a rising position, a string 8 is tensioned to pull up a feed-hot-water main valve 10 to seat it closely in its valve seat 11 to bring the valve 10 into the closed position. At that time when an indoor valve 24 is opened, the negative pressure is produced in a feed-hot-water pipe 16 to allow the air coming into it through an air intake pipe 15, and the hot-water in the outdoor feed hot-water pipe 16 is all drained passing through the feed hot-water valve 24 until the pipe 16 becomes empty. By this method both pipes are prevented from freezing. |
