Butterfly Valves
A fraction of the weight and cost of a gate valve at large sizes.
Quarter-turn valve with a disc rotating in the flow bore. A fraction of the weight and cost of a gate valve at large sizes — the economic answer for large-bore isolation, and up to triple-offset metal-seated designs for steam, cryogenic and refinery duty.
The envelope
| Size range | DN50–DN1200 in the screened envelope |
|---|---|
| Functions | isolation, throttling |
| Seat options | EPDM, NBR, PTFE, METAL |
| Shut-off | Tight shutoff in resilient-seated designs |
| Standards | API 609 (Category A concentric / Category B offset); AWWA C504 for waterworks; ASME B16.34 |
Concentric resilient-seated to Class 150 and ~120 °C (seat-limited); double-offset to Class 600 (metal seat to 450 °C); triple-offset metal-seated designs cover the top of our class range and 600 °C for steam, cryogenic and fire-safe duty. Class here is offset-design-dependent — the report states which design the duty implies. Size×class envelope follows Neway butterfly range (to Class 600) plus Bray McCannalok / Tri Lok and Emerson Vanessa published ranges for the triple-offset classes.
Where it is used
- Large-bore (DN300+) isolation and coarse throttling at low-to-moderate pressure
- Water, air and utility service; tight installation spaces
- Triple-offset metal-seated designs for steam, cryogenic and fire-safe duty
Where it stops
- Concentric resilient-seated tops out at Class 150 and about 120 °C
- The class a butterfly can reach depends on the offset design — the report states which design the duty implies
- Coarse throttling only — not a control valve