The Ventilation Butterfly Valve is a type of butterfly valve specially used for pipeline systems of air, flue gas and industrial gases. It is mainly applied for opening‑closing, isolation and flow regulation of pipeline media.
The ventilation butterfly valve is normally of flanged connection. Manual, gear, electric or pneumatic actuators can be equipped according to different working conditions.For working conditions such as high‑temperature flue gas, hot air and dust‑laden gas, high‑temperature‑resistant materials and metal‑to‑metal sealing structure can be adopted to improve the valve’s temperature resistance, wear resistance and service life.
Working Principle of Ventilation Butterfly Valve:
Opening the Valve: Operate the lever, gear operator, electric or pneumatic actuator to rotate the valve stem and drive the butterfly disc. As the disc gradually turns to a position parallel to the airflow direction inside the pipeline, the flow‑passage area increases, allowing air or flue gas to pass smoothly. The valve reaches the fully‑open position when the disc rotates to approximately 90°.
Closing the Valve: The drive unit rotates the valve stem in the reverse direction, turning the butterfly disc to a position perpendicular to the airflow direction. Once closed, the disc blocks the pipeline passage to isolate air, flue gas or industrial gas.
Flow Regulation: By adjusting the opening angle of the butterfly disc, the effective flow‑through area of the pipeline can be changed to regulate the flow rate of air or flue gas. Intermediate disc opening positions are used for flow control in ventilation systems.
Manual butterfly valves are widely used in industrial piping systems for fast and reliable flow isolation and regulation. Key parameters including working temperature, medium, pressure rating, valve size and connection standard should be confirmed before ordering for proper valve selection. Customized valve sizes, pressure ratings, connection types, sealing materials and body materials are available for diverse industrial and non-standard applications. (Unit: mm)

| DN | inch | Type/Class | Part No | L | H | HO | A | B | D | D1 | D2 | n-d |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 50 | 2 | D41W-PN0.5 | D41WP05XLX2 | 70 | 70 | 286 | 125 | 193 | 140 | 110 | 88 | 4-18 |
| 65 | 2.5 | D41W-PN0.5 | D41WP05XLX2.5 | 112 | 80 | 306 | 125 | 193 | 160 | 130 | 108 | 4-18 |
| 80 | 3 | D41W-PN0.5 | D41WP05XLX3 | 114 | 95 | 334 | 125 | 193 | 190 | 150 | 124 | 4-18 |
| 100 | 4 | D41W-PN0.5 | D41WP05XLX4 | 127 | 105 | 354 | 125 | 193 | 210 | 170 | 144 | 4-18 |
| 125 | 5 | D41W-PN0.5 | D41WP05XLX5 | 140 | 120 | 384 | 125 | 193 | 240 | 200 | 174 | 8-18 |
| 150 | 6 | D41W-PN0.5 | D41WP05XLX6 | 140 | 132 | 409 | 125 | 193 | 265 | 225 | 199 | 8-18 |
| 200 | 8 | D41W-PN0.5 | D41WP05XLX8 | 152 | 160 | 593 | 165 | 183 | 320 | 280 | 254 | 8-18 |
| 250 | 10 | D41W-PN0.5 | D41WP05XLX10 | 165 | 187 | 650 | 165 | 283 | 375 | 335 | 309 | 12-18 |
| 300 | 12 | D41W-PN0.5 | D41WP05XLX12 | 178 | 220 | 715 | 165 | 283 | 440 | 395 | 363 | 12-22 |
| 350 | 14 | D41W-PN0.5 | D41WP05XLX14 | 190 | 245 | 814 | 175 | 334 | 490 | 445 | 413 | 12-22 |
| 400 | 16 | D41W-PN0.5 | D41WP05XLX16 | 216 | 270 | 863 | 175 | 334 | 540 | 495 | 463 | 16-22 |
| 450 | 18 | D41W-PN0.5 | D41WP05XLX18 | 222 | 297 | 918 | 175 | 334 | 595 | 550 | 518 | 16-22 |
| 500 | 20 | D41W-PN0.5 | D41WP05XLX20 | 229 | 322 | 1016 | 210 | 425 | 645 | 600 | 568 | 20-22 |
| 600 | 24 | D41W-PN0.5 | D41WP05XLX24 | 267 | 377 | 1128 | 210 | 425 | 755 | 705 | 667 | 20-26 |
| 700 | 28 | D41W-PN0.5 | D41WP05XLX28 | 292 | 430 | 1233 | 210 | 425 | 860 | 810 | 772 | 24-26 |
| 800 | 32 | D41W-PN0.5 | D41WP05XLX32 | 318 | 487 | 1344 | 210 | 425 | 975 | 920 | 878 | 24-30 |
| 900 | 36 | D41W-PN0.5 | D41WP05XLX36 | 330 | 537 | 1560 | 320 | 620 | 1075 | 1020 | 978 | 24-30 |
| 1000 | 40 | D41W-PN0.5 | D41WP05XLX40 | 410 | 587 | 1660 | 320 | 620 | 1175 | 1120 | 1078 | 28-30 |
| 1200 | 48 | D41W-PN0.5 | D41WP05XLX48 | 470 | 687 | 1890 | 320 | 620 | 1375 | 1320 | 1280 | 32-30 |
| 1400 | 56 | D41W-PN0.5 | D41WP05XLX56 | 530 | 760 | 2670 | 575 | 714 | 1575 | 1520 | 1480 | 36-30 |
| 1600 | 64 | D41W-PN0.5 | D41WP05XLX64 | 600 | 895 | 2810 | 575 | 714 | 1790 | 1730 | 1690 | 40-30 |
| 1800 | 72 | D41W-PN0.5 | D41WP05XLX72 | 670 | 995 | 3020 | 575 | 714 | 1990 | 1930 | 1890 | 44-30 |
| 2000 | 80 | D41W-PN0.5 | D41WP05XLX80 | 760 | 1095 | 3220 | 656 | 810 | 2190 | 2130 | 2090 | 48-30 |
| 50 | 2 | D41W-PN2.5 | D41WP25XLX2 | 70 | 70 | 286 | 125 | 193 | 140 | 110 | 88 | 4-18 |
| 65 | 2.5 | D41W-PN2.5 | D41WP25XLX2.5 | 112 | 80 | 306 | 125 | 193 | 160 | 130 | 108 | 4-18 |
| 80 | 3 | D41W-PN2.5 | D41WP25XLX3 | 114 | 95 | 334 | 125 | 193 | 190 | 150 | 124 | 4-18 |
| 100 | 4 | D41W-PN2.5 | D41WP25XLX4 | 127 | 105 | 354 | 125 | 193 | 210 | 170 | 144 | 4-18 |
| 125 | 5 | D41W-PN2.5 | D41WP25XLX5 | 140 | 120 | 384 | 125 | 193 | 240 | 200 | 174 | 8-18 |
| 150 | 6 | D41W-PN2.5 | D41WP25XLX6 | 140 | 132 | 409 | 125 | 193 | 265 | 225 | 199 | 8-18 |
| 200 | 8 | D41W-PN2.5 | D41WP25XLX8 | 152 | 160 | 593 | 165 | 183 | 320 | 280 | 254 | 8-18 |
| 250 | 10 | D41W-PN2.5 | D41WP25XLX10 | 165 | 187 | 650 | 165 | 283 | 375 | 335 | 309 | 12-18 |
| 300 | 12 | D41W-PN2.5 | D41WP25XLX12 | 178 | 220 | 715 | 165 | 283 | 440 | 395 | 363 | 12-22 |
| 350 | 14 | D41W-PN2.5 | D41WP25XLX14 | 190 | 245 | 814 | 175 | 334 | 490 | 445 | 413 | 12-22 |
| 400 | 16 | D41W-PN2.5 | D41WP25XLX16 | 216 | 270 | 863 | 175 | 334 | 540 | 495 | 463 | 16-22 |
| 450 | 18 | D41W-PN2.5 | D41WP25XLX18 | 222 | 297 | 918 | 175 | 334 | 595 | 550 | 518 | 16-22 |
| 500 | 20 | D41W-PN2.5 | D41WP25XLX20 | 229 | 322 | 1016 | 210 | 425 | 645 | 600 | 568 | 20-22 |
| 600 | 24 | D41W-PN2.5 | D41WP25XLX24 | 267 | 377 | 1128 | 210 | 425 | 755 | 705 | 667 | 20-26 |
| 700 | 28 | D41W-PN2.5 | D41WP25XLX28 | 292 | 430 | 1233 | 210 | 425 | 860 | 810 | 772 | 24-26 |
| 800 | 32 | D41W-PN2.5 | D41WP25XLX32 | 318 | 487 | 1344 | 210 | 425 | 975 | 920 | 878 | 24-30 |
| 900 | 36 | D41W-PN2.5 | D41WP25XLX36 | 330 | 537 | 1560 | 320 | 620 | 1075 | 1020 | 978 | 24-30 |
| 1000 | 40 | D41W-PN2.5 | D41WP25XLX40 | 410 | 587 | 1660 | 320 | 620 | 1175 | 1120 | 1078 | 28-30 |
| 1200 | 48 | D41W-PN2.5 | D41WP25XLX48 | 470 | 687 | 1890 | 320 | 620 | 1375 | 1320 | 1280 | 32-30 |
| 1400 | 56 | D41W-PN2.5 | D41WP25XLX56 | 530 | 760 | 2670 | 575 | 714 | 1575 | 1520 | 1480 | 36-30 |
| 1600 | 64 | D41W-PN2.5 | D41WP25XLX64 | 600 | 895 | 2810 | 575 | 714 | 1790 | 1730 | 1690 | 40-30 |
| 1800 | 72 | D41W-PN2.5 | D41WP25XLX72 | 670 | 995 | 3020 | 575 | 714 | 1990 | 1930 | 1890 | 44-30 |
| 2000 | 80 | D41W-PN2.5 | D41WP25XLX80 | 760 | 1095 | 3220 | 656 | 810 | 2190 | 2130 | 2090 | 48-30 |
| 50 | 2 | D41W-PN6.0 | D41WP60XLX2 | 70 | 70 | 286 | 125 | 193 | 140 | 110 | 88 | 4-18 |
| 65 | 2.5 | D41W-PN6.0 | D41WP60XLX2.5 | 112 | 80 | 306 | 125 | 193 | 160 | 130 | 108 | 4-18 |
| 80 | 3 | D41W-PN6.0 | D41WP60XLX3 | 114 | 95 | 334 | 125 | 193 | 190 | 150 | 124 | 4-18 |
| 100 | 4 | D41W-PN6.0 | D41WP60XLX4 | 127 | 105 | 354 | 125 | 193 | 210 | 170 | 144 | 4-18 |
| 125 | 5 | D41W-PN6.0 | D41WP60XLX5 | 140 | 120 | 384 | 125 | 193 | 240 | 200 | 174 | 8-18 |
| 150 | 6 | D41W-PN6.0 | D41WP60XLX6 | 140 | 132 | 409 | 125 | 193 | 265 | 225 | 199 | 8-18 |
| 200 | 8 | D41W-PN6.0 | D41WP60XLX8 | 152 | 160 | 593 | 165 | 183 | 320 | 280 | 254 | 8-18 |
| 250 | 10 | D41W-PN6.0 | D41WP60XLX10 | 165 | 187 | 650 | 165 | 283 | 375 | 335 | 309 | 12-18 |
| 300 | 12 | D41W-PN6.0 | D41WP60XLX12 | 178 | 220 | 715 | 165 | 283 | 440 | 395 | 363 | 12-22 |
| 350 | 14 | D41W-PN6.0 | D41WP60XLX14 | 190 | 245 | 814 | 175 | 334 | 490 | 445 | 413 | 12-22 |
| 400 | 16 | D41W-PN6.0 | D41WP60XLX16 | 216 | 270 | 863 | 175 | 334 | 540 | 495 | 463 | 16-22 |
| 450 | 18 | D41W-PN6.0 | D41WP60XLX18 | 222 | 297 | 918 | 175 | 334 | 595 | 550 | 518 | 16-22 |
| 500 | 20 | D41W-PN6.0 | D41WP60XLX20 | 229 | 322 | 1016 | 210 | 425 | 645 | 600 | 568 | 20-22 |
| 600 | 24 | D41W-PN6.0 | D41WP60XLX24 | 267 | 377 | 1128 | 210 | 425 | 755 | 705 | 667 | 20-26 |
| 700 | 28 | D41W-PN6.0 | D41WP60XLX28 | 292 | 430 | 1233 | 210 | 425 | 860 | 810 | 772 | 24-26 |
| 800 | 32 | D41W-PN6.0 | D41WP60XLX32 | 318 | 487 | 1344 | 210 | 425 | 975 | 920 | 878 | 24-30 |
| 900 | 36 | D41W-PN6.0 | D41WP60XLX36 | 330 | 537 | 1560 | 320 | 620 | 1075 | 1020 | 978 | 24-30 |
| 1000 | 40 | D41W-PN6.0 | D41WP60XLX40 | 410 | 587 | 1660 | 320 | 620 | 1175 | 1120 | 1078 | 28-30 |
| 1200 | 48 | D41W-PN6.0 | D41WP60XLX48 | 470 | 687 | 1890 | 320 | 620 | 1405 | 1340 | 1295 | 32-33 |
| 1400 | 56 | D41W-PN6.0 | D41WP60XLX56 | 530 | 760 | 2670 | 575 | 714 | 1630 | 1560 | 1510 | 36-36 |
| 1600 | 64 | D41W-PN6.0 | D41WP60XLX64 | 600 | 895 | 2810 | 575 | 714 | 1830 | 1760 | 1710 | 40-36 |
| 1800 | 72 | D41W-PN6.0 | D41WP60XLX72 | 670 | 995 | 3020 | 575 | 714 | 2045 | 1970 | 1918 | 44-39 |
| 2000 | 80 | D41W-PN6.0 | D41WP60XLX80 | 760 | 1095 | 3220 | 656 | 810 | 2265 | 2180 | 2125 | 48-42 |
The manual flanged ventilation butterfly valve adopts a rotary‑disc structure. It features simple construction, compact size, light weight, fast opening‑closing, low flow resistance and easy operation. It is widely used in power generation, metallurgy, iron and steel, cement, chemical industry, boilers, waste‑to‑energy incineration, environmental‑protection projects and industrial ventilation systems.