General technology and pipeline installation project of shahekou water purification factory in dalian water supply system 大连城市供水系统沙河口净水厂改造工程总图工艺管线安装承建工程
4.
Two or more smaller size valves can be piped in parallel ( when approved ) to serve a larger supply pipe main 可以采用并联管线安装两个以上的小通径阀门(需得到批准) ,服务于更大的主供应管道。