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Underground Extended-Stem Fully Welded Ball Valve | Buried Pipeline Valve

Underground Extended-Stem Fully Welded Ball Valve | Buried Pipeline Valve
  • Nominal Diameter: DN50‑DN1400 (2″‑56″)
  • Nominal Pressure: PN16‑PN100 (Class 150‑Class 600)
  • Operation Mode: Handwheel, Gear‑operated
  • Body Material: WC6, WC9, 304, 316L
  • Seat Material: Metal‑to‑Metal
  • Manufacturing Standards: EN1092‑1 / ASME B16.5, EN488‑1:2025, EN 12266‑1, API 6D / ISO 14313, etc.
  • Connection Type: Welded End
  • Operating Temperature: -40°C‑ 425°C
  • Applicable Media: Natural gas, city gas, coal gas, crude oil, refined oil products, gasoline, diesel, liquefied petroleum gas, hot water, circulating water, heat‑transfer media
For technical drawings and 3-D models, click on a part number.

Product details

The Buried‑type Extended‑Stem Fully‑Welded Ball Valve is a high‑performance pipeline ball valve specially designed for underground pipelines, natural‑gas pipe networks, petroleum pipelines and urban district‑heating systems. Constructed with a fully‑welded body and equipped with an extended stem, it elevates the operating actuator above ground or to an accessible position, enabling underground installation of the valve and above‑ground operation.

The fully‑welded body eliminates external leakage points generated by conventional flanged connections, delivering excellent integral strength and sealing performance. The extended‑stem length can be customized according to burial depth, making this valve particularly suitable for deeply‑buried, direct‑buried and space‑constrained underground pipeline systems.

Working Principle of Direct‑Buried Fully‑Welded Ball Valve：
Opening Process: The extended stem is rotated from ground level by a handwheel or worm‑gear drive. The stem drives the ball to rotate 90°, aligning the through‑hole of the ball with the pipeline flow passage. The valve is fully opened and the medium flows through smoothly.

Closing Process: The operating unit is rotated in the reverse direction, turning the ball back by 90°. The solid portion of the ball blocks the flow passage. The seat is pressed tightly against the ball under medium pressure to form a reliable bidirectional seal and cut‑off the medium flow. The extended stem only transmits rotational torque and does not alter the 90° rotary opening‑closing principle of the ball valve.

Product Specifications

Manual ball valves are widely used on piping systems for fast opening and closing, to cut off or connect fluid media stably. Accurate parameter confirmation including working temperature, medium, pressure and caliber is required before ordering for correct valve selection. Customized solutions on valve size, pressure rating, connection standard and body material are available to meet diverse non-standard working conditions.（Unit: mm）

Buried Fully Welded Ball Valve with Extended Stem – PN16-100

DNNPSType/ClassPart NoLAL1DD1D2bfKf2n-φd
50 2MDQ61-PN16MDQ6116XLX2 216 65 178 165 125 99 16 2 //4-18
65 2.5MDQ61-PN16MDQ6116XLX25 241 80 190 185 145 118 18 2 //4-18
80 3MDQ61-PN16MDQ6116XLX3 283 95 203 200 160 132 20 2 //8-18
100 4MDQ61-PN16MDQ6116XLX4 305 115 229 220 180 156 22 2 //8-18
150 6MDQ61-PN16MDQ6116XLX6 457 165 394 285 240 211 24 2 //8-22
200 8MDQ61-PN16MDQ6116XLX8 521 225 457 340 295 266 24 2//12-22
250 10MDQ61-PN16MDQ6116XLX10 559 280 533 405 355 319 26 2 //12-26
300 12MDQ61-PN16MDQ6116XLX12 635 330 610 460 410 370 28 2 //12-26
350 14MDQ61-PN16MDQ6116XLX14 762 385 686 520 470 429 30 2 //16-26
400 16MDQ61-PN16MDQ6116XLX16 838 440 762 580 525 480 32 2 //16-26
450 18MDQ61-PN16MDQ6116XLX18 914 490 864 640 585 548 40 2 //16-30
500 20MDQ61-PN16MDQ6116XLX20 991 550 914 715 650 609 44 2 //20-30
600 24MDQ61-PN16MDQ6116XLX24 1143 660 1067 715 650 609 44 2 //20-33
700 28MDQ61-PN16MDQ6116XLX28 1346 765 1245 960 820 820 50 5 //20-36
800 32MDQ61-PN16MDQ6116XLX32 1524 870 1372 1085 928 928 54 5 //24-36
900 36MDQ61-PN16MDQ6116XLX36 1727 970 1524 1185 1028 1028 58 5 //24-39
1000 40MDQ61-PN16MDQ6116XLX40 1780 1080 1721 1320 1140 1140 62 5 //28-39
1200 48MDQ61-PN16MDQ6116XLX48 2100 1290 2032 1530 1350 1350 70 5 //28-42
1400 56MDQ61-PN16MDQ6116XLX56 2250 1500 2300 1755 1560 1560 76 5 //32-48
50 2MDQ61-PN25MDQ6125XLX2216 70 216 165 125 99 16 2 //4-18
65 2.5MDQ61-PN25MDQ6125XLX25241 85 241 185 145 118 18 2 //8-18
80 3MDQ61-PN25MDQ6125XLX3283 100 283 200 160 132 20 2 //8-18
100 4MDQ61-PN25MDQ6125XLX4305 120 305 220 180 156 22 2 //8-23
150 6MDQ61-PN25MDQ6125XLX6457 170 403 285 240 211 24 2 //8-25
200 8MDQ61-PN25MDQ6125XLX8521 230 502 340 295 266 24 2 //12-25
250 10MDQ61-PN25MDQ6125XLX10559 285 568 405 355 319 26 2 //12-30
300 12MDQ61-PN25MDQ6125XLX12635 335 648 460 410 370 28 2 //16-30
350 14MDQ61-PN25MDQ6125XLX14762 390 762 520 470 429 30 2 //16-33
400 16MDQ61-PN25MDQ6125XLX16838 445 838 580 525 480 32 2 //16-36
450 18MDQ61-PN25MDQ6125XLX18914 495 914 640 585 548 40 2 //20-36
500 20MDQ61-PN25MDQ6125XLX20991 556 991 715 650 609 44 2 //20-36
600 24MDQ61-PN25MDQ6125XLX241143 665 1143 715 650 609 44 2 //20-39
700 28MDQ61-PN25MDQ6125XLX281346 770 1346 960 820 820 50 5 //24-42
800 32MDQ61-PN25MDQ6125XLX321524 880 1524 1085 928 928 54 5 //24-48
900 36MDQ61-PN25MDQ6125XLX361727 980 1727 1185 1028 1028 58 5 //28-48
1000 40MDQ61-PN25MDQ6125XLX401780 1090 2083 1320 1140 1140 62 5 //28-55
1200 48MDQ61-PN25MDQ6125XLX482100 1300 2184 1530 1350 1350 70 5 //32-55
1400 56MDQ61-PN25MDQ6125XLX562250 1520 2300 1755 1560 1560 76 5 //36-60
50 2MDQ61-PN40MDQ6140XLX2216 70 216 165 125 99 18 2 88 4 4-18
65 2.5MDQ61-PN40MDQ6140XLX25241 85 241 185 145 118 20 2 110 4 8-18
80 3MDQ61-PN40MDQ6140XLX3283 100 283 200 160 132 20 2 121 4 8-18
100 4MDQ61-PN40MDQ6140XLX4305 120 305 235 190 160 24 2 150 4.5 8-23
150 6MDQ61-PN40MDQ6140XLX6457 170 403 300 250 218 30 2 204 458-25
200 8MDQ61-PN40MDQ6140XLX8521 230 502 375 320 282 38 3 260 4.5 12-30
250 10MDQ61-PN40MDQ6140XLX10559 290 568 450 385 345 42 3 313 4.5 12-34
300 12MDQ61-PN40MDQ6140XLX12635 340 648 515 450 408 46 4 364 4.5 16-34
350 14MDQ61-PN40MDQ6140XLX14762 395 762 570 510 465 52 4 422 5 16-34
400 16MDQ61-PN40MDQ6140XLX16838 450 838 660 585 535 58 4 474 5 16-41
450 18MDQ61-PN40MDQ6140XLX18914 500 914 685 610 560 60 4 524 5 20-41
500 20MDQ61-PN40MDQ6140XLX20991 560 991 755 670 612 62 4 576 5 20-42
600 24MDQ61-PN40MDQ6140XLX241143 670 1143 890 795 730 62 5 678 5 20-48
700 28MDQ61-PN40MDQ6140XLX281346 780 1346 995 900 835 68 5 768 5 24-48
800 32MDQ61-PN40MDQ6140XLX321524 885 1524 1140 1030 960 76 5 876 5 24-58
900 36MDQ61-PN40MDQ6140XLX361727 985 1727 1270 1168 1095 105 5 986 5 32-54
1000 40MDQ61-PN40MDQ6140XLX401780 1095 2083 1238 1156 1100 114 5 1076 6 32-44
1200 48MDQ61-PN40MDQ6140XLX482100 1310 2184 1467 1372 1302 133 5 1276 6 32-51
1400 56MDQ61-PN40MDQ6140XLX562250 1530 2300 1718 1600 1518 152 5 1486 6 28-60
50 2MDQ61-PN64MDQ6164XLX2292 75 292 180 135 99 26 2 88 4 4-23
65 2.5MDQ61-PN64MDQ6164XLX25330 90 330 205 160 118 26 2 110 4 8-23
80 3MDQ61-PN64MDQ6164XLX3356 105 356 215 170 132 30 2 121 4 8-23
100 4MDQ61-PN64MDQ6164XLX4406 125 406 250 200 160 34 2 150 4.5 8-25
150 6MDQ61-PN64MDQ6164XLX6495 175 495 345 280 240 38 2 204 4.5 8-34
200 8MDQ61-PN64MDQ6164XLX8597 235 597 415 345 300 44 3 260 4.5 12-34
250 10MDQ61-PN64MDQ6164XLX10673 295 673 470 400 352 46 3 313 4.5 12-41
300 12MDQ61-PN64MDQ6164XLX12762 348 762 530 460 412 54 4 364 4.5 16-41
350 14MDQ61-PN64MDQ6164XLX14826 405 826 600 525 475 60 4 422 5 16-41
400 16MDQ61-PN64MDQ6164XLX16902 455 902 670 585 525 66 4 474 5 16-48
500 20MDQ61-PN64MDQ6164XLX201054 570 1054 800 705 640 70 4 576 5 20-54
600 24MDQ61-PN64MDQ6164XLX241232 680 1232 930 820 750 76 5 678 5 20-58
700 28MDQ61-PN64MDQ6164XLX281397 800 1397 1035 940 800 95 5 768 5 28-51
800 32MDQ61-PN64MDQ6164XLX321651 910 1651 1149 1054 914 108 5 876 5 28-54
900 36MDQ61-PN64MDQ6164XLX361880 1020 1880 1270 1168 1095 114 5 986 5 32-54
1000 40MDQ61-PN64MDQ6164XLX401990 1140 1990 1280 117 1100 133 5 1076 6 32-51
1200 48MDQ61-PN64MDQ6164XLX482180 1320 2180 1525 1403 1308 152 5 1276 6 28-60
1400 56MDQ61-PN64MDQ6164XLX562385 1550 2385 1753 1632 1550 190 5 1486 6 32-66
50 2MDQ61-PN100MDQ61100XLX2292 80 292 195 145 99 28 3 88 4 4-26
65 2.5MDQ61-PN100MDQ61100XLX25330 115 330 220 170 118 30 3 110 4 8-26
80 3MDQ61-PN100MDQ61100XLX3356 135 356 230 180 132 32 3 121 4 8-26
100 4MDQ61-PN100MDQ61100XLX4432 185 432 265 210 156 36 3 150 4.5 8-30
150 6MDQ61-PN100MDQ61100XLX6559 245 559 355 290 211 44 3 204 4.5 12-34
200 8MDQ61-PN100MDQ61100XLX8660 310 660 430 360 284 52 3 260 4.5 12-36
250 10MDQ61-PN100MDQ61100XLX10787 355 787 505 430 345 60 3 313 4.5 12-41
300 12MDQ61-PN100MDQ61100XLX12838 410 838 585 500 409 68 3 364 4.5 16-48
350 14MDQ61-PN100MDQ61100XLX14889 465 889 655 560 465 74 4 422 5 16-48
400 16MDQ61-PN100MDQ61100XLX16991 535 991 715 620 535 82 4 474 5 16-48
500 20MDQ61-PN100MDQ61100XLX201194 575 1194 813 724 665 95 5 576 5 24-45
600 24MDQ61-PN100MDQ61100XLX241397 710 1397 940 838 768 102 5 678 5 24-50
700 28MDQ61-PN100MDQ61100XLX281594 830 1594 1130 965 891 118 5 768 5 28-54
800 32MDQ61-PN100MDQ61100XLX321778 970 1778 1194 1080 1000 125 5 876 5 28-60
900 36MDQ61-PN100MDQ61100XLX362083 1055 2083 1315 1194 1100 131 5 986 5 28-67
1000 40MDQ61-PN100MDQ61100XLX402337 1200 2337 1321 1213 1125 166 5 1076 5 32-60
1200 48MDQ61-PN100MDQ61100XLX482400 1430 2400 1594 1461 1360 196 5 1276 5 32-74
1400 56MDQ61-PN100MDQ61100XLX562480 1640 2480 1855 1695 1584 231 5 1486 5 32-86

Featuring an integral fully‑welded body with no potential external leakage from flanged joints, the direct‑buried fully‑welded ball valve is fitted with an extended stem for above‑ground operation, and the stem length can be customized according to burial depth. Its trunnion‑mounted ball structure provides low operating torque, while the straight‑through flow passage ensures low‑flow resistance. Resistant to foundation settlement, seismic load and corrosion, it offers a long maintenance‑free service life and is suitable for underground long‑distance transmission pipelines such as natural‑gas and district‑heating networks.