D342 Double Eccentric Butterfly Valve
• D342F (PTFE seat) and D342X (rubber seat) double eccentric soft-seal butterfly valve, PN6/10/16
• Six seat materials: PTFE, NBR, EPDM, FKM, Silicone, Fluorine plastic — wide temp range −268 to +250 °C
• Size range DN50–DN2000, flanged RF ends, short and long body variants
• Worm gear operated; optional pneumatic or electric actuator
• Suitable for air, water, sewage, steam, gas, oil, and corrosive media
Model: D342F / D342X Series | Pressure: PN6 / PN10 / PN16 | Connection: Flanged | Medium: Water, Air, Oil, Gas, Acid
Gaoshan Valve — D342 Double Eccentric Soft-Seal Butterfly Valve
Double-offset (double eccentric) flanged butterfly valve with worm gear drive, available with PTFE (F) or rubber (X) seat and 6 seat material options for sizes up to DN2000 across PN6, PN10, and PN16 pressure ratings.
Product Overview
The D342F/D342X is a double-offset (double eccentric) soft-seal butterfly valve designed for demanding isolation and flow control applications from DN50 to DN2000. Unlike centerline wafer valves, the double eccentric geometry lifts the disc away from the seat during the opening stroke — the first offset shifts the shaft behind the disc centreline, the second offset inclines the shaft relative to the pipe axis. This cam-like motion reduces seat friction, lowers operating torque, extends seat life, and enables a tighter bi-directional seal. Flanged end connections ensure rigid pipe alignment and simplify installation in large-bore and high-pressure systems. A manual worm gear drive is standard; pneumatic and electric actuator assemblies are available on request. With six seat material options ranging from cryogenic PTFE (−268 °C) to high-temperature silicone rubber (250 °C), the D342 covers the widest temperature and chemical compatibility range in the Gaoshan butterfly valve portfolio.
Model Designation Guide
| Model Code | Pressure | Body Material | Seat Designation | Typical Application |
|---|---|---|---|---|
| D342F-6/10/16 | PN6 / 10 / 16 | Specify: —, Q, or C | F = PTFE (polytetrafluoroethylene) | Corrosive chemicals, high temperature, cryogenic |
| D342X-6/10/16 | PN6 / 10 / 16 | Specify: —, Q, or C | X = Rubber (NBR / EPDM / FKM / Silicone) | Water, air, sewage, gas, petroleum, food processing |
| Body: — | — | Gray Cast Iron / Ductile Iron | Standard body (omitted in code) | General water & low-pressure service |
| Body: Q | — | Ductile Cast Iron (QT450-10) | Example: D342F-10Q | Elevated impact / pressure shock duty |
| Body: C | — | WCB Cast Steel / Stainless Steel | Example: D342X-16C | High pressure, steam, petrochemical |
Seat Material Selection Guide
| Material Code | Seat Material | Max Temp | Min Temp | Working Temp | Best For |
|---|---|---|---|---|---|
| X (FKM) | Fluorine Rubber (Viton) | 82 °C | −40 °C | ≤65 °C | Oils, fuels, chemical media at moderate temp |
| J (NBR) | Nitrile Rubber (Buna-N) | 93 °C | −40 °C | ≤80 °C | Water, petroleum, oil, general industrial |
| YBX (EPDM) | Ethylene Propylene Diene Monomer | 150 °C | −40 °C | ≤120 °C | Steam, hot water, polar fluids, HVAC |
| F (PTFE) | Polytetrafluoroethylene (Teflon) | 232 °C | −268 °C | ≤200 °C | Strong acids, oxidisers, cryogenic, high-temp dry |
| GX (VMQ) | Silicone Rubber | 250 °C | −70 °C | ≤200 °C | Food processing, pharmaceuticals, high-temp air |
| FJ (FEP) | Fluorine Plastic (Fluorinated Polyethylene) | 204 °C | −23 °C | ≤180 °C | Chemical processing, semi-corrosive, high temp |
Key Advantages
Technical Specifications
| Parameter | PN6 | PN10 | PN16 |
|---|---|---|---|
| Nominal Pressure | 6 bar (0.6 MPa) | 10 bar (1.0 MPa) | 16 bar (1.6 MPa) |
| Shell Test Pressure | 0.9 MPa | 1.5 MPa | 2.4 MPa |
| Seal Test Pressure | 0.66 MPa | 1.1 MPa | 1.76 MPa |
| Air Tightness Test | 0.6 MPa | ||
| Size Range | DN50 – DN2000 (2″ – 80″) | ||
| End Connection | Flanged, Raised Face (RF) per GB/T 17241 / ISO 7005 | ||
| Disc Type | Double eccentric (double-offset) disc | ||
| Operation | Worm gear (standard); pneumatic / electric actuator optional | ||
| Seat Type | Soft-seal: PTFE, NBR, EPDM, FKM, Silicone, or FEP | ||
| Applicable Medium | Air, water, sewage, steam, gas, oil, weak acid, alkali | ||
| Design Standard | GB/T 12238; GB/T 13927 (pressure test) | ||
Materials of Main Parts
| Component | Standard (—) | Q Body | C Body |
|---|---|---|---|
| Body | Gray Cast Iron / Ductile Iron | Ductile Cast Iron (QT450-10) | WCB Cast Steel / SS |
| Disc | Gray Cast Iron / Ductile Iron | Ductile Cast Iron | Cast Steel / Stainless Steel |
| Seat Ring | PTFE / NBR / EPDM / FKM / Silicone / FEP (as selected) | ||
| Stem / Shaft | 2Cr13 Stainless Steel / SS304 / SS316 (on request) | ||
| Stem Packing | O-Ring (NBR/FKM) / Flexible Graphite | ||
| Worm Gear | Ductile Iron housing; alloy steel worm & gear | ||
| Fasteners | Carbon Steel / Stainless Steel (as specified) | ||
Applicable Media by Seat Type
Sewage / Wastewater
Steam (≤250 °C)
Compressed Air
Natural Gas / Coal Gas
Petroleum / Fuel Oil
Weak Acid
Alkali / Caustic
Food / Beverage
HVAC Hot/Chilled Water
Fire Protection
Cryogenic (LNG / LOX)
Principal Dimensions (mm) — All Pressure Classes
| DN | in. | L (Short) | L (Long) | H1 | H | L1 | L2 | D1 |
|---|---|---|---|---|---|---|---|---|
| 80 | 3 | 114 | 180 | 102 | 390 | 52 | 127 | 160 |
| 100 | 4 | 127 | 190 | 112 | 430 | 52 | 127 | 160 |
| 125 | 5 | 140 | 200 | 128 | 483 | 52 | 127 | 160 |
| 150 | 6 | 140 | 210 | 145 | 520 | 52 | 127 | 160 |
| 200 | 8 | 152 | 230 | 185 | 668 | 80 | 150 | 240 |
| 250 | 10 | 155 | 250 | 220 | 725 | 80 | 150 | 240 |
| 300 | 12 | 178 | 270 | 250 | 788 | 80 | 150 | 280 |
| 350 | 14 | 190 | 290 | 280 | 848 | 80 | 150 | 280 |
| 400 | 16 | 216 | 310 | 316 | 1004 | 136 | 218 | 320 |
| 450 | 18 | 222 | 330 | 344 | 1058 | 136 | 218 | 320 |
| 500 | 20 | 229 | 350 | 370 | 1145 | 136 | 218 | 320 |
| 600 | 24 | 267 | 390 | 440 | 1380 | 124 | 238 | 500 |
| 700 | 28 | 292 | 430 | 505 | 1475 | 124 | 238 | 500 |
| 800 | 32 | 318 | 470 | 570 | 1600 | 124 | 238 | 500 |
| 900 | 36 | 330 | 510 | 630 | 1742 | 176 | 259 | 500 |
| 1000 | 40 | 410 | 550 | 690 | 1866 | 176 | 259 | 500 |
| 1200 | 48 | 470 | 630 | 820 | 2200 | 176 | 259 | 500 |
| 1400 | 56 | 530 | 710 | 950 | 2530 | 292 | 371 | 560 |
| 1600 | 64 | 600 | 790 | 1100 | 2850 | 290 | 371 | 560 |
| 1800 | 72 | 670 | 870 | — | 1796 | — | — | — |
| 2000 | 80 | 760 | 950 | — | 3075 | — | — | — |
L (Short) = compact face-to-face, L (Long) = standard face-to-face; H1 = centerline to top of valve body; H = overall gearbox height; L1 = gearbox width; L2 = gearbox depth; D1 = flange bolt-circle diameter. All values in mm. PN6 / PN10 / PN16 share identical face-to-face dimensions. — = consult factory for DN1800–DN2000 actuator dimensions.
Double Eccentric vs. Centerline Butterfly Valve
| Feature | D342 Double Eccentric | D71X / D371X Centerline |
|---|---|---|
| Disc motion | Cam-lift (wiping action) | Rub / compress against seat |
| Seat friction during opening | Minimal — lifts off clean | Moderate — compression drag |
| Max size | DN2000 | DN500 |
| End connection | Flanged (RF) | Wafer |
| Seat replaceability | Yes — serviceable insert | Bonded to body |
| Seat material range | 6 materials, −268 to 250 °C | NBR only, max 135 °C |
| Best for | Critical service, large bore, aggressive media | General industrial, small-medium bore |
Product Structure Diagram
Quality Assurance & Testing
Every D342 butterfly valve undergoes the following factory acceptance tests before shipment:
- Shell Pressure Test — hydrostatic test at 1.5×PN to verify body and flange integrity.
- Seat Leakage Test — bi-directional water or air test at 1.1×PN; Class VI zero leakage per GB/T 13927.
- Air Tightness Test — pneumatic seat test at 0.6 MPa to confirm bubble-tight shutoff in gas service.
- Gearbox Functional Test — full open/close cycle under differential pressure; torque and limit verification.
- Dimensional Inspection — face-to-face (short & long), flange bolt-circle, and bore dimensions per GB/T 12238.
- Seat Material Verification — each seat lot is hardness-tested and thermally qualified against the selected material specification.
Installation & Maintenance Notes
- Orientation: Install with the shaft horizontal or vertical (preferred for DN600+). Ensure adequate clearance above the gearbox for handwheel operation.
- Flange alignment: Align pipe flanges precisely before inserting the valve. Use full-face or spiral-wound gaskets compatible with the media and temperature.
- Disc position during installation: Leave the disc slightly open (5°–10°) to protect the seat edge from flange face damage during bolt tightening.
- Seat replacement: The soft seat is a field-replaceable insert. No special tools required — remove retaining ring, swap seat, re-torque evenly.
- Periodic inspection: Inspect the seat every 6–12 months. Replace if cracking, swelling, or permanent set exceeding 10% of original thickness.
- Gearbox lubrication: Check worm gear grease every 2,000 cycles. Replenish with EP2 lithium grease or as specified by the actuator manufacturer.
Ordering Information
| Item | Specify When Ordering |
|---|---|
| Model | D342F or D342X — plus pressure class (6 / 10 / 16) and body designation (, Q, or C) |
| Nominal Size | DN50 – DN2000 |
| Face-to-Face Length | Short (compact) or Long (standard) |
| Seat Material | FKM (X) / NBR (J) / EPDM (YBX) / PTFE (F) / Silicone (GX) / FEP (FJ) |
| Disc Material | Ductile Iron (standard); SS304 / SS316 / Special alloy on request |
| Shaft Material | 2Cr13 (standard); SS304 / SS316 / Duplex on request |
| Flange Standard | GB/T 17241 (standard); ANSI B16.5 / DIN EN 1092 on request |
| Actuator Option | Worm gear (standard); pneumatic (DA/SR); electric (on/off/modulating) |
Request a Quote or Technical Support
Gaoshan Valve supplies D342 double eccentric butterfly valves with certified inspection reports, seat material traceability, and actuator documentation. Reverse-engineering support available for legacy valve replacement. Contact our team for pricing, CAD drawings, and application-specific seat recommendation.