The double eccentric high‑performance butterfly valve adopts offset valve stem and eccentric disc. Its lip‑type compensation seat absorbs temperature and pressure variation during operation. Available in soft‑seated and metal‑seated versions, it delivers excellent bi‑directional sealing performance. Featuring simple structure, light weight, high flow capacity, durable reliable sealing, large adjustable range, high regulating accuracy and omni‑directional mounting, it is suitable for automatic regulation or shut‑off in various industrial processes.

Working Principle

Based on single‑eccentric sealing butterfly valve, the double eccentric butterfly valve further offsets the disc rotation axis from the valve body channel center by dimension b. At fully open position, the disc sealing surface completely separates from seat with enlarged clearance y. The disc rotation radius forms long‑radius and short‑radius sections. On the large semicircle of long‑radius rotation, the tangent of disc sealing trace forms angle β against seat surface. During opening and closing, the disc sealing surface gradually disengages and squeezes against seat, reducing mechanical wear and scratching between disc and seat.

When opening from 0‑90°, the disc sealing surface separates from seat faster than single‑eccentric butterfly valves. At 8°‑12° rotation from closed position, disc sealing surface fully departs from seat. It shortens the squeezing‑rotation travel, lowers mechanical abrasion, and greatly improves sealing performance and service life.

Structural Design

The energy‑storage flexible lip seat of high‑performance double eccentric butterfly valve provides good elasticity and reliable sealing. The flexible lip compensates temperature and pressure fluctuation without extra O‑rings or metal auxiliary sealing parts. It features long service life and low maintenance. Bi‑directional sealing test achieves zero‑bubble leakage.

Product Features

1. Valve Body: One‑piece integrated body design.

2. Pressure Ring: Specially designed pressure ring guarantees sealing tightness and fits various flange gaskets.

3. Seat: Realizes bi‑directional pressure holding. Install pressure ring on upstream side of pipeline.

4. Bearing: Upper and lower bearings made of PTFE+316SS.

5. Thrust Ring: Prevents valve shaft offset and stabilizes shaft position.

6. Packing: Multi‑layer PTFE packing structure.

7. Bracket: Cast structure complying with ISO 5211 standard.

Main Component Materials

Technical Parameters

Installation & Maintenance

Installation: Align valve arrow with medium flow direction, avoid reverse mounting. Tighten flange bolts with torque wrench to keep flange and gasket flat and parallel.

Maintenance: Carry out regular maintenance for stable performance and long service life, including sealing performance inspection, internal dirt cleaning, checking and replacing damaged sealing parts.

With simple structure, easy operation, low flow resistance, reliable sealing and wide adaptability, double eccentric butterfly valves are widely adopted across multiple industrial sectors.

Application Fields

Double eccentric high‑performance butterfly valves are widely applied for flow regulation and medium shut‑off in water supply‑drainage and gas pipelines of food, pharmaceutical, chemical, petroleum, power, textile and paper‑making industries.