During the operation of the pipeline, the gas in the water will escape to accumulate in the high starting point of the pipeline and even form a gas resistance. When the water flow in the pipeline fluctuates, the balloon formed by the raised part will be continuously compressed, expanded and compressed After the pressure generated, than the pressure generated by water after the compression of a few times or even hundreds of times, when the pipeline is extremely prone to rupture. Therefore, the design of the exhaust pipe valve design, usually in the rolling ups and downs of the plains, the trench should be artificially designed pipeline ups and downs, the cycle up or down, the slope of not less than 1/500, every kilometer at the highest set 1 -2 exhaust valve, in the rolling hills or mountains, should be at the highest point of each fluctuation, set an exhaust valve, exhaust valve specifications are the original pipe diameter 1 / 8-1 / 10.