Large Diameter Plate Flat Welding Flange, commonly known as Large PL Flange, is a widely used flat welding flange designed for large-diameter piping systems.In the industry, flanges with DN650 and above (NPS 26 and larger) are generally classified as large diameter plate flat welding flanges.
The flange adopts a flat plate structure. During installation, the pipe is inserted into the flange bore and welded with the flange by fillet welding on both the inner and outer sides, forming a reliable permanent connection. Two mating flanges are then tightened with bolts to compress the gasket and achieve effective face sealing performance.
Large Diameter Plate Flat Welding Flanges feature a simple structure, easy installation, and cost-effective manufacturing, making them widely used in municipal pipelines, water treatment systems, petrochemical plants, energy projects, and large industrial piping networks.
Note: The flange inner diameter (B) is determined by the wall thickness of the steel pipe and shall be specified by the user at the time of ordering.（Unit: mm）
| DN | NPS | Type/Class | Part No | D | K | L | Th | n | C | d1 | f |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 650 | 26 | LPL-150LB-SFT | XLXLPL150SFT26 | 870 | 806.4 | 36 | M33 | 24 | 66.7 | / | 1.5 |
| 700 | 28 | LPL-150LB-SFT | XLXLPL150SFT28 | 925 | 863.6 | 36 | M33 | 28 | 69.9 | / | 1.5 |
| 750 | 30 | LPL-150LB-SFT | XLXLPL150SFT30 | 985 | 914.4 | 36 | M33 | 28 | 73.1 | / | 1.5 |
| 800 | 32 | LPL-150LB-SFT | XLXLPL150SFT32 | 1060 | 977.9 | 42 | M39 | 28 | 79.4 | / | 1.5 |
| 850 | 34 | LPL-150LB-SFT | XLXLPL150SFT34 | 1110 | 1028.7 | 42 | M39 | 32 | 81 | / | 1.5 |
| 900 | 36 | LPL-150LB-SFT | XLXLPL150SFT36 | 1170 | 1085.8 | 42 | M39 | 32 | 88.9 | / | 1.5 |
| 950 | 38 | LPL-150LB-SFT | XLXLPL150SFT38 | 1240 | 1149.4 | 42 | M39 | 32 | 85.8 | / | 1.5 |
| 1000 | 40 | LPL-150LB-SFT | XLXLPL150SFT40 | 1290 | 1200.2 | 42 | M39 | 36 | 88.9 | / | 1.5 |
| 1050 | 42 | LPL-150LB-SFT | XLXLPL150SFT42 | 1345 | 1257.3 | 42 | M39 | 36 | 95.3 | / | 1.5 |
| 1100 | 44 | LPL-150LB-SFT | XLXLPL150SFT44 | 1405 | 1314.4 | 42 | M39 | 40 | 100.1 | / | 1.5 |
| 1150 | 46 | LPL-150LB-SFT | XLXLPL150SFT46 | 1455 | 1365.2 | 42 | M39 | 40 | 101.6 | / | 1.5 |
| 1200 | 48 | LPL-150LB-SFT | XLXLPL150SFT48 | 1510 | 1422.4 | 42 | M39 | 44 | 106.4 | / | 1.5 |
| 1250 | 50 | LPL-150LB-SFT | XLXLPL150SFT50 | 1570 | 1479.6 | 48 | M45 | 44 | 109.6 | / | 1.5 |
| 1300 | 52 | LPL-150LB-SFT | XLXLPL150SFT52 | 1625 | 1536.7 | 48 | M45 | 44 | 114.3 | / | 1.5 |
| 1350 | 54 | LPL-150LB-SFT | XLXLPL150SFT54 | 1685 | 1593.8 | 48 | M45 | 44 | 119.1 | / | 1.5 |
| 1400 | 56 | LPL-150LB-SFT | XLXLPL150SFT56 | 1745 | 1651 | 48 | M45 | 48 | 122.3 | / | 1.5 |
| 1450 | 58 | LPL-150LB-SFT | XLXLPL150SFT58 | 1805 | 1708.2 | 48 | M45 | 48 | 127 | / | 1.5 |
| 1500 | 60 | LPL-150LB-SFT | XLXLPL150SFT60 | 1855 | 1759 | 48 | M45 | 52 | 130.2 | / | 1.5 |
The flange adopts a thick circular plate structure with sufficient load-bearing capacity, making it suitable for large-diameter pipeline connections.
Compared with Weld Neck Flanges (WN Flanges), the installation process is simpler and requires less welding preparation.
The flange connection is completed by tightening bolts between two mating flanges, compressing various gasket types.
Especially suitable for large pipeline systems requiring frequent assembly and maintenance.
