正三通根據連接形式分為下表中的6種,中間字母表示分支端的連接形式。法蘭接頭密封形式同樣有兩種。
| 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帶電熔,可以直接與直管電熔焊接。