适用范围 ：适用于水利系统、市政污水、城市防洪排涝、污水处理厂、自来水厂拍门具有流道正向单向开启和反向关闭的作用。拍门的阀盖借助于自身配重的平衡作用，在水流的作用下使门页自动开启或关闭，或稍加外力作用使门页开启或关闭；拍门盖上设有拉环，拉动拉环此盖的开启角度应大于60度，无卡阻现象，开关应自由灵活，当铸铁拍门部分泡在水中，管道内部压力较大，反向压力较小时，拍门允许部分泄漏量，当河道水压增大时，拍门将自动关闭密封。The flap door has the function of forward one-way opening and reverse closing of the flow path. The valve cover of the flap door can automatically open or close the door under the action of water flow with the help of the balance of its counterweight, or open or close the door with a slight external force; the flap cover is provided with a pulling ring, and the opening angle of the pulling ring of the cover should be greater than 60 degrees, without jamming phenomenon, and the switch should be free and flexible, when the flap part is soaked in water In the middle of the pipeline, when the internal pressure is high and the reverse pressure is low, the flap door allows part of the leakage, and when the river water pressure increases, the flap door will automatically close and seal.