When priming water into the pipe starts, the cock stays at the opened position to let a great deal of exhaust and, at the end of exhaust, the water gathered inside of the pipe makes the floating ball up to cause the cock to the closed position. When a little quantity of air gathers in the pipe and gets to a proper degree during the normal water transportation, the water level inside of the pipe lowers again, at this time the air is exhausted from the small holes. When the water extractor stops and the water inside of the pipe flows up or a negative pressure is formed, the cock is opened to suck air in to make sure of the pipeline safety. |
