首先我们说下大型法兰的连接标准
| 大型法兰公称通经DN | 大型法兰连接尺寸 | 大型法兰密封面 | 法兰厚度C | 大型法兰法兰颈 | ||||||
| 法兰外经D | 螺栓孔中心圆直径K | 螺栓孔径L | 螺栓 | d | f | N | R | |||
| 数量n | 螺纹规格 | |||||||||
| 10 | 90 | 60 | 14 | 4 | M12 | 41 | 2 | 14 | 28 | 3 |
| 15 | 95 | 65 | 14 | 4 | M12 | 46 | 2 | 14 | 32 | 3 |
| 20 | 105 | 75 | 14 | 4 | M12 | 56 | 2 | 16 | 40 | 4 |
| 25 | 115 | 85 | 14 | 4 | M12 | 65 | 2 | 16 | 50 | 4 |
| 32 | 140 | 100 | 18 | 4 | M16 | 76 | 2 | 18 | 60 | 5 |
| 40 | 150 | 110 | 18 | 4 | M16 | 84 | 2 | 18 | 70 | 5 |
| 50 | 165 | 125 | 18 | 4 | M16 | 99 | 2 | 20 | 84 | 6 |
| 65 | 185 | 145 | 18 | 4 | M16 | 118 | 2 | 22 | 104 | 6 |
| 80 | 200 | 160 | 18 | 8 | M16 | 132 | 2 | 24 | 120 | 6 |
| 100 | 235 | 180 | 22 | 8 | M20 | 156 | 2 | 24 | 142 | 8 |
| 125 | 270 | 210 | 26 | 8 | M24 | 184 | 2 | 26 | 162 | 8 |
| 150 | 300 | 240 | 26 | 8 | M24 | 211 | 2 | 28 | 192 | 10 |
| 200 | 360 | 295 | 26 | 8 | M24 | 274 | 2 | 30 | 252 | 10 |
| 250 | 425 | 350 | 30 | 12 | M27 | 330 | 2 | 32 | 304 | 10 |
| 300 | 485 | 400 | 30 | 12 | M27 | 389 | 2 | 34 | 364 | 10 |
| 350 | 555 | 460 | 33 | 16 | M30 | 448 | 2 | 38 | 418 | 12 |
| 400 | 620 | 515 | 36 | 16 | M33 | 503 | 2 | 40 | 472 | 12 |
| 450 | 670 | 565 | 36 | 20 | M33 | 548 | 2 | 46 | 520 | 12 |
| 500 | 730 | 620 | 36 | 20 | M33 | 609 | 2 | 48 | 580 | 12 |
| 600 | 845 | 725 | 39 | 20 | M36 | 720 | 2 | 58 | 684 | 12 |
| 700 | 960 | 840 | 42 | 24 | M39 | 820 | 5 | 50 | 780 | 12 |
| 800 | 1085 | 950 | 48 | 24 | M45 | 928 | 5 | 54 | 882 | 12 |
| 900 | 1185 | 1050 | 48 | 28 | M45 | 1028 | 5 | 58 | 982 | 12 |
| 1000 | 1320 | 1160 | 55 | 28 | M52 | 1140 | 5 | 62 | 1086 | 12 |
| 1200 | 1530 | 1380 | 55 | 32 | M52 | 1350 | 5 | 70 | 1296 | 12 |
| 1400 | 1755 | 1590 | 60 | 36 | M56 | 1560 | 5 | 76 | 1508 | 12 |
| 1600 | 1975 | 1820 | 60 | 40 | M56 | 1780 | 5 | 84 | 1726 | 12 |
| 1800 | 2195 | 2020 | 68 | 44 | M56 | 1985 | 5 | 90 | 1920 | 15 |
| 2000 | 2425 | 2230 | 68 | 48 | M64 | 2210 | 5 | 96 | 2150 | 15 |
大型法兰连接方式是一种管路连接方式，具体是指在管路对接的两端铸有法兰，在法兰端面上开有密封槽，槽内装密封圈，对接好后用螺栓或双头螺柱将管路紧紧连在一起。