D371X Gear-Operated Wafer Butterfly Valve
• Models: D371X-10/10Q/10C (PN10) and D371X-16/16Q/16C (PN16) — six variants for every duty
• Size range DN50–DN500, worm gear drive for smooth torque multiplication on larger bores
• Body in gray cast iron, ductile iron, or WCB cast steel; Buna-N rubber seat & O-ring
• 2Cr13 SS stem, ductile iron disc, aluminium bronze bushings; ISO 5211 pad for actuator option
• Rated for water, steam, oil, weak acid and alkali up to 135 °C
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Product Details
The D371X gear operated wafer butterfly valve is the worm-gear-driven member of our resilient seated wafer family: the same centerline, rubber-lined design as the lever-operated D71X, extended to DN50–DN500 where a lever would need excessive torque. The worm gearbox multiplies handwheel input so one person can cycle the disc smoothly even at full differential pressure — PN10 / PN16, up to 135°C.
- Worm gear handwheel drive — smooth, low-effort operation with self-locking position hold on larger bores
- DN50–DN500, six variants: gray cast iron / ductile iron / WCB cast steel bodies at PN10 and PN16
- Full Buna-N (NBR) rubber seat and O-ring — bi-directional zero-leakage shut-off
- 2Cr13 stainless steel stem, ductile iron disc, aluminium bronze bushings
- ISO 5211 top pad on the gearbox accepts multi-turn electric actuators for later automation
- Water, steam, petroleum, weak acid and alkali service up to 135°C
Product Overview
The D371X is the worm-gear-driven variant of the D71X wafer butterfly valve family, extending the same centerline-disc, rubber-seated design to larger pipe sizes (DN50–DN500) where a manual lever would require excessive operating torque. The worm gearbox multiplies handwheel input torque, allowing one person to smoothly open and close the disc even under full differential pressure. Six standard variants cover PN10 and PN16 pressure classes with three body material options — gray cast iron, ductile cast iron and WCB cast steel — all sharing the same wafer face-to-face dimensions per GB/T 12238. A Buna-N elastomer lining delivers tight bi-directional shutoff for water, steam, petroleum, weak acids and alkalis, and an ISO 5211 top pad on the gearbox housing accepts pneumatic or electric actuators for automated service.
Model Designation Guide
| Model | Pressure | Body Material | Operation |
|---|---|---|---|
| D371X-10 | PN10 | Gray Cast Iron (HT200) | Worm gear |
| D371X-10Q | PN10 | Ductile Cast Iron (QT450) | Worm gear |
| D371X-10C | PN10 | WCB Cast Steel | Worm gear |
| D371X-16 | PN16 | Gray Cast Iron (HT200) | Worm gear |
| D371X-16Q | PN16 | Ductile Cast Iron (QT450) | Worm gear |
| D371X-16C | PN16 | WCB Cast Steel | Worm gear |
D371X (Gear) vs. D71X (Lever)
Both valves share one centerline wafer body and NBR seat; the choice is about bore size and how often the valve is operated.
| Feature | D371X (This Product) | D71X (Lever Type) |
|---|---|---|
| Drive | Worm gear / handwheel | Manual lever |
| Size range | DN50 – DN500 | DN40 – DN200 |
| Operating effort | Low (geared reduction) | Higher on large sizes |
| Position indicator | Handwheel turns / limit stops | Lever notch steps |
| Typical application | Larger bore, frequent operation, automation-ready | Small bore, intermittent manual service |
Rule of thumb: lever-operated D71X for small bores and occasional operation; the gear-operated D371X from DN200 upward or wherever the valve cycles frequently. For remote or automated operation see the pneumatic D671X and electric D971X.
Key Advantages
Worm Gear Torque Multiplication
The self-locking worm gearbox reduces handwheel effort significantly, enabling one-person operation even on DN300–DN500 valves under full differential pressure. No separate gearbox adapter required.
Compact Wafer Design
Short face-to-face length (L = 43–127 mm) minimises pipeline spool length and installation space. Installs between any standard PN10/16 flanges without dedicated lugs.
Three Body Material Options
Gray cast iron for economy fresh water, ductile iron for improved impact resistance, or WCB cast steel for high-pressure steam and petrochemical service — all interchangeable in the same piping space.
Full NBR Elastomer Seal
The Buna-N rubber seat ring and O-ring provide tight bi-directional shutoff across the full rated pressure range, with zero seat leakage per GB/T 13927 testing.
Wide Service Media Range
Rated for steam, water, seawater, petroleum, fuel oil, weak acid, and alkali solutions up to 135°C. Covering HVAC, water treatment, fire protection, and industrial process systems.
ISO 5211 Actuator Pad
Standard ISO 5211 top flange on the gearbox allows direct mounting of pneumatic or electric multi-turn actuators without bracket modification.
Technical Specifications
| Parameter | PN10 Models | PN16 Models |
|---|---|---|
| Nominal Pressure (PN) | 10 bar (1.0 MPa) | 16 bar (1.6 MPa) |
| Shell Test Pressure | 1.5 MPa | 2.4 MPa |
| Seal Test Pressure | 1.1 MPa | 1.8 MPa |
| Working Temperature | ≤ 135 °C | ≤ 135 °C |
| Size Range | DN50 – DN500 | DN50 – DN500 |
| End Connection | Wafer (between-flange, centerline) | Wafer (between-flange, centerline) |
| Operation | Worm gear handwheel (standard); actuator optional | Worm gear handwheel (standard); actuator optional |
| Applicable Medium | Steam, water, petroleum, weak acid, alkali | Steam, water, petroleum, weak acid, alkali |
| Design Standard | GB/T 13927 (pressure test); GB/T 12238 (face-to-face) | GB/T 13927 (pressure test); GB/T 12238 (face-to-face) |
Applicable Media
- Steam (≤135°C)
- Water
- Seawater
- Petroleum
- Fuel Oil
- Weak Acid
- Alkali
- HVAC Water
- Fire Protection
Materials of Construction
| Component | D371X-10 / -16 | D371X-10Q / -16Q | D371X-10C / -16C |
|---|---|---|---|
| Body | Gray Cast Iron (HT200) | Ductile Cast Iron (QT450) | WCB Cast Steel |
| Seat Ring | Buna-N Rubber (NBR) | Buna-N Rubber (NBR) | Buna-N Rubber (NBR) |
| Stem / Worm | 2Cr13 Stainless Steel | 2Cr13 Stainless Steel | 2Cr13 Stainless Steel |
| Disc | Ductile Cast Iron (QT450) | Ductile Cast Iron (QT450) | Ductile Cast Iron (QT450) |
| Axis Bushing | Aluminium Bronze | Aluminium Bronze | Aluminium Bronze |
| O-Ring Seal | Buna-N Rubber (NBR) | Buna-N Rubber (NBR) | Buna-N Rubber (NBR) |
Principal Dimensions (mm) & Weight (kg) — PN10 / PN16
| DN | L | H1 | H2 | H3 | L1 | S | D0 | Weight |
|---|---|---|---|---|---|---|---|---|
| DNDN50 | 43 | 68 | 118 | 64 | 96 | 53 | 100 | 6 |
| DNDN65 | 46 | 82 | 140 | 64 | 96 | 53 | 100 | 7 |
| DNDN80 | 46 | 85 | 150 | 64 | 96 | 53 | 126 | 9 |
| DNDN100 | 52 | 105 | 180 | 64 | 96 | 53 | 126 | 12 |
| DNDN125 | 56 | 128 | 200 | 64 | 96 | 53 | 160 | 13 |
| DNDN150 | 56 | 138 | 210 | 64 | 96 | 53 | 160 | 18 |
| DNDN200 | 60 | 175 | 245 | 100 | 150 | 80 | 250 | 26 |
| DNDN250 | 68 | 205 | 280 | 100 | 150 | 80 | 250 | 42 |
| DNDN300 | 78 | 245 | 320 | 117 | 220 | 100 | 320 | 78 |
| DNDN350 | 78 | 265 | 340 | 117 | 220 | 100 | 320 | 81 |
| DNDN400 | 102 | 295 | 380 | 128 | 274 | 205 | 320 | 142 |
| DNDN450 | 114 | 326 | 420 | 128 | 274 | 205 | 320 | 160 |
| DNDN500 | 127 | 345 | 460 | 158 | 403 | 298 | 620 | 190 |
L = face-to-face length; H1 = centerline to top of body; H2 = centerline to handwheel top; H3 = gearbox center height; L1 = handwheel length; S = stem square dimension; D0 = handwheel diameter; Weight = approximate net weight including gearbox. PN10 and PN16 share identical external dimensions.
Butterfly Valve Family at a Glance
| Type | Models | Seat | Characteristics | Typical Service |
|---|---|---|---|---|
| Centerline wafer | D71X / D371X (this page) / D671X / D971X | Rubber (NBR / EPDM) | Lightest & most economical; PN10 / PN16; ≤135°C | Water, HVAC, general service |
| Double eccentric (high performance) | D342 / D642 / D942 | Rubber / PTFE | Large bores, PN6–PN16, low operating torque | Water mains, large pipelines |
| Triple offset (metal seated) | D343H / D363H | Laminated metal | High temperature & high pressure service | Steam, hot oil, petroleum |
Browse the whole butterfly valve series or compare drive options for the same wafer body: D71X (manual lever), D371X (worm gear), D671X (pneumatic) and D971X (electric).
Structure Drawing
Quality Assurance & Testing
Every D371X gear-operated butterfly valve undergoes the following factory acceptance tests before shipment:
- Shell Pressure Test — hydrostatic test at 1.5×PN to verify body integrity.
- Seat Leakage Test — air or water test at rated pressure; zero seat leakage required per GB/T 13927.
- Gearbox Cycling Test — full open/close operation under differential pressure to confirm worm gear smoothness and self-locking capability.
- Dimensional Inspection — face-to-face, handwheel, flange and all mounting pad dimensions checked against GB/T 12238.
- Visual & NDT — casting surfaces inspected; critical welds (cast steel models) subject to dye-penetrant examination.
Installation & Maintenance Notes
- Orientation: D371X valves may be installed in any pipe orientation. Keep the gearbox accessible for future handwheel operation and actuator retrofit.
- Flange bolts: Use through-bolts to clamp both pipe flanges together through the wafer body. Tighten in a cross pattern to avoid rubber seat distortion.
- Gearbox lubrication: The worm gearbox is factory-greased and sealed; no routine re-lubrication is required under normal service. Inspect grease condition during scheduled plant shutdowns.
- Rubber seat inspection: Inspect the NBR seat annually or after prolonged steam service. Replace if cracking, swelling or permanent set is observed.
- Stem packing: The stem uses O-ring sealing; no packing adjustment required. Replace O-rings if leakage is detected.
- Actuator upgrade: The ISO 5211 top pad on the gearbox accepts standard multi-turn electric actuators. Remove the handwheel and bolt the actuator directly to the pad.
International Standards & Certification
The D371X family is manufactured and tested to Chinese national standards with international equivalents available on request: face-to-face dimensions to GB/T 12238, pressure testing to GB/T 13927, and flange drilling to GB/T 17241 as standard. On request we quote and certify to EN 593 or API 609 design equivalents, and the ISO 5211 actuator mounting pad is machined as standard.
- CE-marked (EU PED) and holding API 6D plus ISO 9001 / ISO 14001 / ISO 45001 management system certification
- China pressure-pipeline valve manufacturing license held by the factory
- Every valve passes shell and seat leakage tests before shipment; factory inspection report included
- EN 593 / API 609 conformance documentation on request
Why Buy D371X from Gaoshan Valve
Since 1975, Henan Gaoshan Valves Co., Ltd. has manufactured CE, API 6D and ISO 9001/14001/45001 certified valves for petrochemical, power, water treatment and HVAC customers in more than 20 countries, and is an approved supplier to Sinopec and CNPC. Every D371X ships with a factory inspection report covering shell and seat leakage tests.
- 50 years of valve manufacturing behind every order
- CE-marked, API 6D and ISO 9001/14001/45001 certified production
- Approved supplier to Sinopec and CNPC; exports to 20+ countries
- Common DN50–DN500 variants in stock; custom configurations and actuated assemblies on request
Frequently Asked Questions
What is the difference between the D371X and the D71X?
They share the same centerline wafer body and NBR rubber seat. The D371X adds a worm gearbox and covers DN50–DN500, where a manual lever would need excessive torque; the lever-operated D71X runs DN40–DN200. Choose the gear version for larger bores or frequently cycled valves.
What sizes and pressures are available?
DN50–DN500 across PN10 and PN16, in six model variants: gray cast iron, ductile iron or WCB cast steel body at each pressure class. PN10 and PN16 share identical external dimensions.
Does the worm gear hold position when I stop turning?
Yes. The worm gearbox is self-locking, so the disc stays where you set it without a locking device. Self-locking capability is verified on every valve during the factory gearbox cycling test.
Can the D371X be automated later?
Yes. The gearbox carries a standard ISO 5211 top pad that accepts multi-turn electric actuators — remove the handwheel and bolt the actuator directly to the pad. Pneumatic actuated versions are supplied as the D671X.
Which seat materials and temperatures does it support?
NBR (Buna-N) is standard for water, steam, petroleum, weak acid and alkali service up to 135°C. EPDM or PTFE-lined seats are available on request — send the medium and temperature for a recommendation.
What testing and certificates come with the valve?
Each valve passes a shell test at 1.5×PN, a seat leakage test to GB/T 13927, a gearbox cycling test and dimensional inspection to GB/T 12238 before shipment, and the factory inspection report is included. CE, API 6D and ISO 9001/14001/45001 certificates are available.
Ordering Information
| Item | Specify When Ordering |
|---|---|
| Model | D371X-10 / 10Q / 10C / 16 / 16Q / 16C |
| Nominal Size | DN50 – DN500 |
| Flange Drilling Standard | GB/T 17241 (standard); ANSI / DIN on request |
| Operation Type | Worm gear handwheel (standard); electric actuator optional |
| Seat Material | NBR (standard); EPDM / PTFE-lined on request |
| Disc Coating | Standard ductile iron; nickel-plated or SS disc on request |
Related Butterfly Valves
D71X Wafer Butterfly Valve — the lever-operated small-bore sister model. D671X Pneumatic Wafer Butterfly Valve — pneumatic actuation of the same wafer body. D363H Triple Offset Butterfly Valve and D942 Electric Double Eccentric Butterfly Valve — move up to metal-seated or double-eccentric duty when temperature or pressure outgrow the resilient seat.
Get a Quote & Technical Support
Gaoshan Valve supplies D371X gear-operated wafer butterfly valves with certified inspection reports. Sizes DN50–DN500 stocked in common variants; custom configurations and actuated assemblies available. Contact our team for pricing, torque charts and application guidance — reply within 24 hours.
