Model: D371X Series  |  Pressure: PN10 / PN16  |  Connection: Wafer (Gear)  |  Medium: Water, Steam, Oil, Acid

Gaoshan Valve — D371X Gear-Operated Wafer Butterfly Valve

Worm gear driven centerline wafer butterfly valve with rubber-lined disc, available in six body/pressure variants for water, steam, petroleum, and mild chemical service up to 135 °C. DN50–DN500.

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. An ISO 5211 top pad on the gearbox housing accepts pneumatic or electric actuators for automated service.

Model Designation Guide

D371X (Gear) vs. D71X (Lever) — Quick Selection

Key Advantages

Technical Specifications

Materials of Main Parts

Applicable Media

Principal Dimensions (mm) & Weight (kg) — PN10 / PN16

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.

Product Structure Diagram

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 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 detected.
• Actuator upgrade: The ISO 5211 top pad on the gearbox accepts standard multi-turn electric actuators. Remove handwheel and bolt actuator directly to the pad.

Ordering Information