Butterfly Valve

Product Overview

The Butterfly Valve (Wafer & Lug Type) is a quarter-turn rotary valve designed for reliable flow control and tight shut-off across a wide range of industrial, commercial, and municipal applications. Available in nominal diameters from DN50 to DN1200, it offers an economical and space-saving alternative to gate and globe valves while delivering excellent flow characteristics and low pressure drop.

Rated for PN10 and PN16 working pressures, these valves are engineered to meet the demands of water distribution networks, HVAC systems, fire protection pipelines, and general industrial service. They comply with internationally recognised standards including ANSI, DIN, and JIS, ensuring broad compatibility with existing piping infrastructure.

Construction Details

Body Materials

The valve body is available in two primary materials to suit different service conditions:

• Ductile Iron (GGG40/GGG50): Offers superior strength, impact resistance, and corrosion resistance compared to grey cast iron. Ideal for water supply, irrigation, and HVAC applications.
• Carbon Steel (WCB): Suited for higher-temperature industrial service, steam lines, and applications requiring greater mechanical strength.

Disc and Stem

The disc is typically manufactured from ductile iron with a nickel-plated or epoxy-coated finish, or from stainless steel (SS304/SS316) for corrosive media. The stem is constructed from stainless steel to resist corrosion and ensure long service life. A non-rising stem design minimises installation space requirements.

Seat and Lining Materials

The resilient seat lining provides bubble-tight shut-off and is available in two elastomer options:

• EPDM (Ethylene Propylene Diene Monomer): Excellent resistance to water, steam, ozone, and weathering. Recommended for potable water, hot water, and HVAC service. Temperature range: –20 °C to +120 °C.
• NBR (Nitrile Butadiene Rubber): Superior resistance to oils, fuels, and hydrocarbons. Suitable for petroleum products and general industrial fluids. Temperature range: –20 °C to +80 °C.

Wafer Type vs. Lug Type

Both configurations share the same internal components and performance characteristics. The key difference lies in how they interface with the pipeline flanges:

• Wafer Type: Sandwiched between two pipe flanges using through-bolts. Compact, lightweight, and cost-effective. Suitable for most standard installations where the pipeline does not need to be isolated at the valve for downstream removal.
• Lug Type: Features threaded inserts (lugs) around the body perimeter, allowing the valve to be bolted independently to each flange. Enables dead-end service — one side of the pipeline can be removed without disturbing the other, making it ideal for systems requiring frequent maintenance or end-of-line installation.

Operator Options

The valve is available with multiple operator configurations to suit manual, semi-automatic, and fully automated control requirements:

• Lever Operator: Standard for smaller sizes (typically DN50–DN200). Provides quick quarter-turn operation with a locking notch plate for intermediate positions.
• Gear Operator (Worm Gearbox): Recommended for larger sizes (DN200 and above) where higher torque is required. Provides precise throttling control and self-locking capability to prevent unintended movement.
• Actuator-Ready (ISO 5211 Mounting Pad): All valves feature an ISO 5211 top flange for direct mounting of electric, pneumatic, or hydraulic actuators, enabling integration into automated control systems.

Size Range and Pressure Ratings

The valve range covers nominal diameters from DN50 (2") to DN1200 (48"), making it one of the most comprehensive butterfly valve series available. Pressure ratings of PN10 (10 bar / 145 psi) and PN16 (16 bar / 232 psi) are supported, with the appropriate rating depending on valve size and body material selection. Face-to-face dimensions conform to ISO 5752 (short pattern) and EN 558 Series 20.

Applicable Standards

These butterfly valves are designed and tested in accordance with the following international standards:

• Design & Testing: API 609, EN 593
• Face-to-Face: ISO 5752, EN 558
• Flanges: ANSI B16.5 / B16.47, DIN 2501, JIS B2210
• Pressure Testing: EN 12266-1, API 598
• Potable Water Approval: WRAS (where applicable)

Typical Applications

The versatility of this butterfly valve makes it suitable for a broad spectrum of applications:

• Water Distribution: Municipal water supply mains, pumping stations, and water treatment plants.
• HVAC Systems: Chilled water, condenser water, and heating circuits in commercial and industrial buildings.
• Fire Protection: Sprinkler system isolation and control in accordance with NFPA 13.
• Industrial Pipelines: Process water, cooling water, slurries, and non-aggressive chemical service.
• Irrigation: Agricultural and landscape irrigation networks.
• Marine and Offshore: Seawater cooling and ballast systems (with appropriate material selection).

Installation Notes

Butterfly valves may be installed in any orientation — horizontal, vertical, or inclined — though horizontal stem orientation is preferred for larger sizes to minimise disc sag. Ensure adequate clearance for disc rotation during installation. For wafer-type valves, align the valve centrally between flanges before tightening bolts in a cross-pattern sequence. Lug-type valves should be bolted to each flange independently, verifying thread engagement depth.

A minimum straight pipe run of 5× DN upstream and 2× DN downstream is recommended to ensure stable flow conditions and accurate control. Avoid installing the valve immediately downstream of pumps, elbows, or other flow-disturbing fittings without adequate straight pipe.

Maintenance

Butterfly valves require minimal routine maintenance. Periodic inspection should include checking for seat leakage, stem seal integrity, and operator condition. The resilient seat is replaceable in the field without removing the valve body from the pipeline (on supported models). Gear operators should be lubricated annually or per the manufacturer's schedule. Actuated valves should be functionally tested at regular intervals to verify open/close travel and torque output.