正三通根据连接形式分为下表中的6种,中间字母表示分支端的连接形式。法兰接头密封形式同样有两种。
| 50 | 65 | 80 | 100 | 125 | 150 | 200 | 250 | 300 | 350 | 400 | 450 | 500 | 600 |
DDD | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ●* |
FDD | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ●* |
FDF | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ●* |
FFF | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ●* |
DFF | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ●* |
DFD | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ●* |
注:DN600三通垂直端接口自带电熔,可以直接与直管电熔焊接。