止回阀在管路中的作用是阻止液体倒流,它在高层建筑管道系统以及锅炉、泵站中得到广泛的应用。从止回阀的内部结构看,可分为升降式止回阀和旋启式止回阀两种,升降式止回阀又分为卧式和立式,分别适用于水平管路和垂直管路上,而旋启式止回阀既适用于水平管路又适用于垂直管路。图1为旋启式止回阀 The function of the check valve in the pipeline is to prevent the liquid from flowing backward. It is widely used in high-rise building piping systems as well as in boilers and pumping stations. Seen from the internal structure of the check valve, it can be divided into two types: lift check valve and swing check valve. The lift check valve is divided into horizontal and vertical, which are applicable to horizontal pipes and vertical pipes respectively. On the road, swing check valves are suitable for both horizontal and vertical lines. Figure 1 is a swing check valve