Introduction to Butterfly Valves
A butterfly valve is a quarter-turn valve used to control or isolate fluid flow in pipelines.
It features a disc mounted on a rotating shaft. When turned 90°, the disc either allows fluid to pass or blocks it completely.
Butterfly valves are popular for:
- Low-cost installation compared to other valves like gate or globe valves
- Compact design requiring less space and weight in pipelines
- Fast operation for quick shut-off or throttling
Related: [Lug Type, Flanged & Stainless Steel Butterfly Valves – Specs & Prices]
Why Use a Butterfly Valve?
Advantages
- Compact & Lightweight – Requires less material and space.
- Quick Operation – Opens or closes in one-quarter turn (90°).
- Cost-Effective – Affordable for large-diameter pipelines.
- Versatile – Handles liquids, gases, slurries, and some solids.
- Low Maintenance – Fewer parts compared to other valve types.
Limitations
- Not ideal for high differential pressure – May cause disc deflection.
- Possible pressure drop – Disc remains in the flow path even when fully open.
- Not for abrasive slurries – Can cause wear on the disc and seat.
Main Types of Butterfly Valves
Butterfly valves are classified based on connection type, design, and application.
| Type | Design Feature | Common Use | Pros | Cons |
|---|---|---|---|---|
| Wafer Type | Fits between two flanges, secured with bolts | HVAC, water pipelines | Cost-effective, lightweight | Cannot be dismantled without pipeline shut-down |
| Lug Type | Threaded inserts on both sides for independent disconnection | Fire protection, industrial use | Allows one side of pipeline to be disconnected | More expensive than wafer type |
| Double Flanged | Flanges on both ends for secure bolting | Large-diameter waterworks | Stronger joint, easy centering | Heavier & bulkier |
| Double Offset | Shaft is offset from disc center & bore center | Steam, high-pressure lines | Less seat wear, better sealing | Higher cost |
| Triple Offset | Third offset in sealing surface | High-temp, high-pressure industrial service | Zero leakage, long life | Most expensive |
See also: [Double Flanged Butterfly Valve – High Performance & Applications]
Butterfly Valve Parts & Their Functions
- Body – Outer casing, connects to pipe flanges.
- Disc – Main flow control element; rotates to open/close.
- Stem/Shaft – Connects actuator/handle to the disc.
- Seat – Provides sealing between disc and body.
- Bushings/Bearings – Reduce friction during rotation.
- Actuator/Handle – Manual lever, gearbox, or powered actuator.
- Seals & O-Rings – Prevent leakage along shaft.
Tip: Choose seat materials (EPDM, NBR, PTFE) based on fluid type and temperature.
Butterfly Valve Working Principle
When the actuator or handle turns the shaft:
- Open Position (90°) – Disc is parallel to flow, minimal resistance.
- Closed Position (0°) – Disc is perpendicular to flow, blocking passage.
- Throttling – Intermediate positions regulate flow rate.
Butterfly valves operate on the principle of axial rotation with a sealing mechanism at the disc edge and seat.
Technical Specifications
| Parameter | Typical Range |
|---|---|
| Size Range | 40 mm to 2000 mm |
| Pressure Rating | PN 6, PN 10, PN 16, Class 150, Class 300 |
| Temperature Range | -40°C to +250°C (material dependent) |
| Body Materials | Cast Iron, Ductile Iron, Stainless Steel, PVC |
| Disc Materials | SS 304, SS 316, CI, DI, Aluminum Bronze |
| Seat Materials | EPDM, NBR, PTFE, Viton |
| End Connection | Wafer, Lug, Flanged |
Butterfly Valve Selection Guide
When choosing a butterfly valve:
- Determine Fluid Type – Water, oil, chemicals, slurry.
- Check Pressure & Temperature – Match with valve rating.
- Choose Connection Type – Wafer for cost-saving, lug/flanged for isolation capability.
- Select Seat & Disc Materials – Based on chemical compatibility.
- Decide Actuation Method – Manual lever, gear operator, pneumatic, or electric.
Installation & Maintenance Tips
- Inspect flanges for damage before installation.
- Use correct gasket type for flange sealing.
- Tighten bolts in crisscross pattern for even load distribution.
- Regularly check for seat wear and replace if necessary.
- Lubricate stem and actuator parts periodically.
Applications Across Industries
- Water Treatment Plants – Flow control in pipelines.
- HVAC Systems – Chilled and hot water regulation.
- Fire Protection – Used in sprinkler systems.
- Chemical Plants – For corrosive fluid handling.
- Marine Industry – Seawater cooling lines.
- Food & Beverage – Hygienic stainless steel designs.
Butterfly Valve Pricing in India 2025
Prices vary based on size, type, material, and brand.
| Size | Wafer Type CI (₹) | Lug Type CI (₹) | SS 304 Wafer (₹) |
|---|---|---|---|
| 2″ | 750 | 1,050 | 2,300 |
| 4″ | 1,250 | 1,750 | 3,800 |
| 6″ | 2,100 | 2,900 | 6,200 |
| 8″ | 3,400 | 4,800 | 9,900 |
For brand-specific prices for reference , see: [Lug Type, Flanged & Stainless Steel Butterfly Valves – Specs & Prices]
HSN Code for Butterfly Valves
- 8481.80 – Taps, cocks, valves for pipes, boiler shells, tanks, vats, etc. (including butterfly valves).
Frequently Asked Questions
Q1: Can butterfly valves be used for throttling?
A: Yes, they can regulate flow, but for precise control, globe valves are preferred.
Q2: What’s the lifespan of a butterfly valve?
A: Typically 5–15 years, depending on material, usage, and maintenance.
Q3: Are butterfly valves bidirectional?
A: Most are, but always check manufacturer specs.
Where to Buy in 2025
Udhhyog supplies wafer, lug, and flanged butterfly valves across India.
+91 9311120784 | Udhhyog.com | Request a Quote
