What Is a Vacuum Butterfly Valve?
A vacuum butterfly valve is a centric butterfly valve whose seat and design are rated for negative pressure. The disc rotates 90° between open and closed and seals against an elastomer seat. The key requirement is that the seat stays dimensionally stable inside the body even under vacuum.
Why the Vulcanized EPDM Seat Stays Tight Under Vacuum
The EPDM seat is vulcanized directly into the body, forming a permanent bond. Because the liner cannot move, it will not be drawn in or displaced under negative pressure – the precondition for tight shut-off in vacuum service. A bonded fixed liner is suitable for vacuum conditions because there is no movement or wear of the liner. Tightness of metallic industrial valves is verified to EN 12266 (leakage rate A) for resilient-seated discs.
Technical Data at a Glance
Fergo vacuum butterfly valves are easy to select by DN, PN and body type:
- Nominal size: DN40 to DN300
- Connection: flange PN6 / PN10 / PN16, ANSI Class 150
- Body type: wafer (AK210V) or lug (AK211V)
- Face-to-face: to EN 558-1, Series 20
- Body: ductile iron GGG40, epoxy-coated
- Seat: EPDM, vulcanized
- Disc: stainless steel
- Temperature range: −20 °C to +110 °C
- Top flange: ISO 5211
- Operation: hand lever (actuator-ready)
Wafer or Lug Body for Vacuum?
The wafer design AK210V is clamped between two flanges and is the economical standard solution. The lug design AK211V has threaded inserts and allows one pipe side to be removed while the line stays in service – useful when a line end must remain shut off. Both versions use the same tight-sealing EPDM seat.
Typical Applications
Fergo vacuum butterfly valves are used for:
- Vacuum lines and process systems
- Shut-off of gases and liquids under negative pressure
- Chemical, pharmaceutical and plant engineering
- Machine building, OEM and automation solutions
To match the seal to your medium, the Fergo chemical resistance tool helps you verify EPDM and alternative sealing materials.
Automation via ISO 5211
The ISO 5211 top flange is the standardized interface for actuator mounting and allows direct fitting of a hand lever, gearbox or quarter-turn actuator. For automated control, pair the valve with a unit from actuators & accessories – for example the compact J4C electric actuator.
Fergo vacuum butterfly valves combine a tight, vacuum-rated design with standardized connections and ISO 5211 automation. Select your valve directly in the product filter or browse all butterfly valves – and contact our technical team for any sizing questions.
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