Triple Offset Butterfly Valve BVT01 — Metal Sealing
The BVT01 is a triple offset butterfly valve manufactured to order, based on the supplied specifications. DN 80 to 2000, temperatures from −196 °C to +850 °C, pressures up to ANSI 900 LB. Each unit is sized for a specific application, fluid and service conditions.
How does the triple offset butterfly valve work?
Triple offset geometry is based on three geometric displacements of the disc relative to the shaft axis and the pipe centreline. This design causes the disc to lift off the seat from the very first degree of rotation: no metal-to-metal contact during operation, only in the closed position.
Sealing is achieved by the reaction of the metal seat against the disc ring, with no intermediate friction. Wear is virtually zero over the valve’s service life. Unlike single or double offset valves, there is no progressive seal deformation caused by open-close cycles, which is why the triple offset butterfly valve is specified whenever service conditions exceed what an elastomer or PTFE seal can withstand.
Technical advantages of the triple offset butterfly valve
- Best weight / face-to-face / nominal diameter ratio on the market for metal-to-metal valves
- Face-to-face dimensions per EN 558 series 20, direct replacement on existing installations
- High flow coefficient thanks to the two-piece disc and shaft design (low pressure drop)
- Bolted-on body seat: replacement of wear parts directly on site, no factory removal required
- Internal sleeve protection ring: prevents any particle ingress during operation
- Intrinsic fire-safe under pressure (BS 6755 part 2, API 607)
- ISO 5211 mounting pad, interchangeable actuators, compatible with electric, pneumatic and hydraulic operation
- Seat tailored to each application: flexible graphite, solid stainless steel or one-piece disc
BVT01 Range — Dimensions and specifications
- DN: 80 to 2000
Body: Steel P265GH / A216WCB / SS CF8M / Duplex / AISI 310 - Disc: Steel P265GH / A216WCB / SS CF8M / Duplex / AISI 310
- Seat: Flexible graphite / Solid stainless steel seal / One-piece disc
- End connections: Wafer, threaded, flange series 13 and 14, butt-weld end
- Temperature: −196 °C to +850 °C
- Pressure: PN 10 to PN 250 / ANSI 150 LB to ANSI 1500 LB
- Sealing: Bidirectional zero leakage — API 598, EN 12266-1, ANSI/FCI 70-2 class VI
- Fire safety: API 607
- Flow characteristic: equal percentage and linear between 60° and 80° opening
Industrial applications
The triple offset butterfly valve is used wherever elastomer seal solutions cannot withstand the service conditions.
Saturated steam and thermal power plants. Temperatures rapidly exceed 400 to 500 °C on steam circuits. The metal-to-metal construction withstands these conditions without seat deformation. Steam turbines, high-pressure district heating networks, cogeneration: these are the most common applications in the energy sector.
Petrochemical and refining. Corrosive and flammable fluids require zero-leakage sealing cycle after cycle. The BVT01 with stainless steel or duplex body meets API 609 requirements and API 607 fire-safe ratings, for applications where leakage is not an option.
Cryogenics. The BVT01 range operates down to −196 °C with suitable materials — austenitic stainless steel, AISI 310. LNG, liquid nitrogen and oxygen applications.
Other applications: seawater desalination, processing and treatment plants, vacuum circuits, offshore oil, high-temperature industrial heating.
Frequently asked questions about the triple offset butterfly valve
What is the difference between single, double and triple offset?
A centred valve places the disc on the centreline: it rubs against the seat on every cycle. Double offset shifts the shaft, reducing friction, but the seal remains elastomeric. Triple offset adds a third conical geometric displacement that eliminates all contact during rotation. The disc only contacts the seat in the closed position, under the effect of pressure. This is the only configuration that delivers metal-to-metal sealing without progressive seat wear.
Under what conditions is the triple offset butterfly valve required?
Whenever conditions exceed what an elastomer or PTFE seal can withstand: temperatures above 250 °C, corrosive or abrasive fluids, mandatory fire-safe application, cryogenics, or very frequent operating cycles. Below these thresholds, a double offset is often sufficient and less costly. Our engineers can help you determine the right choice for your project.
Is the BVT01 compatible with my existing installation?
Yes. The BVT01 is available in wafer, flange series 13 and 14, threaded or butt-weld end connections. The face-to-face dimension follows EN 558 series 20, allowing direct replacement without modifying the pipework. For non-standard dimensions, each triple offset butterfly valve is manufactured to order.
What are the lead times?
Each BVT01 is produced to order. Lead time depends on the selected materials, options (actuators, coating, FAT/SAT testing) and volumes. Submit your specifications via the configurator or directly to our engineers — we will provide a technical offer with specifications, lead time and firm price within 48 hours.
