What are the three distinctive designs of the butterfly valve?

The choice identifying wafer, double flanged, and lug-wafer as the three distinctive designs of a butterfly valve is accurate because each of these designs reflects a common and functional method of connecting butterfly valves within various piping systems.

The wafer design is notable for its compact profile, allowing it to be inserted between two flanges without the need for additional support. This makes the wafer design lightweight and cost-effective, suitable for applications where space is limited.

The double flanged design incorporates flanges on both ends, facilitating direct attachment to the piping system. This design is typically used in applications requiring a secure and rigid connection, ensuring that the valve maintains its integrity under pressure.

The lug-wafer design is unique because it features lugs that enable the valve to be bolted directly to the piping, providing stability while allowing for easier removal and maintenance without needing to remove the entire piping system.

Understanding these designs is crucial for selecting the appropriate valve type based on the specific installation requirements, pressure ratings, and maintenance considerations within a steamfitting context.