I. Structural Classification: Evolution from Basic to Precision
1. Centered-Seal Butterfly Valve (Concentric Butterfly Valve)
Core Feature: The valve stem, disc center, and valve body center are aligned, offering a simple structure.
Performance Limitations:
Full-circumference squeezing friction during operation causes wear, with a short sealing life (typically ≤100,000 cycles).
Suitable only for low-pressure (PN≤1.6MPa), moderate-temperature (-20°C~80°C) media like water/air, e.g., municipal water supply pipelines.
Typical Models: D71X (wafer type), D41X (flanged type).
2. Single-Offset Butterfly Valve
Design Improvement: The stem is offset by ~1/3 of the disc radius to reduce friction.
Technical Breakthrough:
The disc partially disengages from the seat during opening, reducing wear by 30–50%.
Compatible with rubber seals (e.g., EPDM) for zero leakage, ideal for clean pipelines in food/pharmaceutical industries.
Limitation: Sealing pairs deform under high pressure, limiting pressure resistance to ≤4.0MPa.
3. Double-Offset Butterfly Valve
Structural Upgrade: The stem is offset from both the disc and valve body centers, creating a "double eccentricity."
Performance Enhancement:
The disc fully disengages from the seat at startup, eliminating friction and extending lifespan to >500,000 cycles.
Adapts to metal seals (e.g., stainless steel + graphite), withstanding temperatures up to 425°C for high-temperature steam pipelines in petrochemical/metallurgy.
Typical Applications: Blast furnace gas pipelines, boiler bypass systems.
4. Triple-Offset Butterfly Valve
Revolutionary Design: Adds a 3°–5° inclined sealing surface to double offset, forming a "3D eccentricity."
Core Advantages:
Zero-Leakage Hard Seal: Achieves metal-to-metal sealing via mechanical compression (API 609 VI leakage class).
High-Pressure/Temperature Resistance: Rated for 25MPa and -196°C~700°C, used in LNG tanks/nuclear steam lines.
Dead-Zone-Free Regulation: Precise flow control (0°–90° opening) with a 100:1 turndown ratio, outperforming traditional control valves.
Typical Models: D373H (flanged), D643W (pneumatic triple-offset).
II. Drive Type Classification: Adapting to Automation & Harsh Conditions
1. Manual Drive
Operation: Handwheel, worm gear, or lever.
Application: Small-diameter (DN≤200mm), infrequent-use pipelines (e.g., lab equipment, small water treatment).
2. Pneumatic Drive
Actuators: Double-acting (continuous air supply) or single-acting (spring-return) cylinders.
Technical Features:
Fast response (≤5s), ideal for quick shut-off/regulation.
High explosion-proof rating (e.g., ATEX), suitable for hazardous environments (oil/gas, pharmaceuticals).
Typical Use: Aseptic filling lines (with hygienic valves), chemical reactor feed control.
3. Electric Drive
Control Modes: On/off (position feedback) or modulating (4–20mA signal).
Advantages:
Remote automation (e.g., municipal wastewater plants).
High-precision control (e.g., reflux ratio in distillation towers).
Limitation: Lower explosion-proof performance than pneumatic, requiring additional protection.
4. Hydraulic Drive
Power Source: Hydraulic oil (5–21MPa).
Applications:
Large-diameter (DN≥1200mm), high-torque pipelines (e.g., hydroelectric tailwater).
Harsh environments (e.g., offshore platforms) with vibration/shock resistance.
III. Sealing Performance: From Soft to Hard Seals
1. Soft-Seal Butterfly Valve
Materials: NBR, EPDM, PTFE.
Features:
Excellent sealing (bubble-tight), but limited to ≤150°C.
Cost-effective for water, oil, and mild chemicals.
Applications: HVAC chilled water, purified water systems.
2. Hard-Seal Butterfly Valve
Sealing Pairs: Stainless steel + tungsten carbide, cobalt alloy + graphite.
Advancements:
Withstands extreme conditions (700°C, 25MPa), e.g., aerospace fuel systems.
Resists abrasive media (slurries, coal dust).
Limitation: High precision required, 3–5× costlier than soft-seal.
IV. Specialized Butterfly Valves: Custom Solutions for Extreme Conditions
1. High-Temperature Butterfly Valve
Design: HK45 alloy (1150°C), thermal expansion gaps.
Use: Glass furnace flues, waste incinerators.
2. Cryogenic Butterfly Valve
Materials: 304L stainless steel, nickel alloy (-196°C).
Sealing: Polyimide (PI) rings to prevent brittleness.
Application: LNG tank inlets/outlets.
3. Abrasion-Resistant Butterfly Valve
Innovation: Tungsten carbide coating (HV1200 hardness), full-bore design (≤15m/s flow).
Use: Mine tailings, cement plant pipelines.
4. Vacuum Butterfly Valve
Specs: ≤10⁻⁴Pa vacuum, for semiconductor coating/vacuum furnaces.
Sealing: Metal bellows + FKM gaskets to prevent air leakage.
V. Connection Types: Adapting to Installation Needs
| Type | Features | Limitations |
|---|---|---|
| Wafer | No flanges, space-saving (30% less) | Unsuitable for high-pressure/vibration |
| Flanged | Robust, high-pressure (PN≤25MPa), easy maintenance | Bulkier |
| Clamp | Quick installation (10s), ideal for CIP cleaning in food industry | Limited pressure rating |
| Welded | Zero leakage, for subsea pipelines/nuclear reactors | Permanent, non-removable |
VI. Selection Guide: Matching Requirements Precisely
| Parameter | Recommended Valve Type |
|---|---|
| Corrosive Media | Lined PTFE (e.g., D71F46) |
| Abrasive Media | Triple-offset hard seal + tungsten carbide coating |
| High-Pressure/Temp | Triple-offset metal seal (e.g., D343H) |
| Vacuum | Vacuum butterfly valve (e.g., GI type) |
| Fast Shut-Off | Pneumatic (e.g., D643W) |
| Precision Control | Electric (e.g., D943W) |
| Cost-Effective | Centered soft-seal (e.g., D71X) |
| Longevity | Triple-offset hard seal (≥10 years) |
Contact Us For Butterfly Valve Product List