Descrição
Metal seated severe-service butterfly valve
Válvula borboleta tripla de aço inoxidável
A compact quarter-turn isolation valve using triple-offset geometry to reduce seat wear and support reliable metal-seated closure at elevated temperature or demanding pressure conditions.
What is a stainless steel triple offset butterfly valve?
A triple offset butterfly valve separates the shaft from the seat centerlines and adds a conical sealing geometry. This causes the disc and seat to disengage rapidly during opening and approach contact only near final closure, reducing sliding friction compared with concentric or double-offset resilient-seated designs.
The metal sealing system can suit elevated temperature, fire-safe and severe isolation duties, but performance depends on the exact seat stack, seal ring, body pattern, pressure direction, shaft support and actuator torque. Leakage class and bidirectional capability must be confirmed for the offered design.
Triple offset butterfly valve specifications
| Produto | Stainless steel triple offset butterfly valve |
|---|---|
| Body patterns | Wafer, lug, double-flanged or butt-weld according to design |
| Geometry | Triple offset / eccentric metal seated construction |
| Body materials | ASTM A351 CF8/CF8M/CF3/CF3M; duplex or nickel alloy by specification |
| Disc and shaft | Stainless steel or service-specific alloy selected for load and corrosion |
| Seat system | Laminated or solid metal seal ring with graphite or engineered layers where applicable |
| Classificação de pressão | ASME Class or PN rating verified against material, temperature and body pattern |
| Flow direction | Preferred or bidirectional capability according to qualified design |
| Operação | Gear operator, pneumatic, electric or hydraulic actuator |
| Optional features | Fire-safe design, live-loaded packing, locking, emergency shutdown and partial-stroke testing when specified |
| Documentação | Material records, relatório de teste de pressão, torque data, GA drawing and inspection dossier as ordered |
The table describes typical engineered supply options, not a universal stock range. Final size, pressure-temperature rating, aparar, assento, operator and end connection must be confirmed against the purchase specification and applicable code edition.
Stainless steel and alloy material options
| Família de materiais | Common cast designations | Typical selection basis |
|---|---|---|
| Austenitic stainless steel | ASTM A351 CF8, CF8M, CF3 and CF3M | Resistência geral à corrosão; CF8M/CF3M adds molybdenum for improved chloride resistance. |
| Duplex stainless steel | ASTM A995/A890 4A and related 2205 grades | Higher strength and improved chloride stress-corrosion resistance when properly specified. |
| Super duplex stainless steel | ASTM A995/A890 5A or 6A | Água do mar, offshore and high-chloride service subject to temperature and fabrication controls. |
| Nickel alloy | ASTM A494 grades matching C276, Liga 20, Monel or other ordered chemistry | Selected from actual process chemistry, concentração, temperature and contamination data. |
Projeto, testing and project compliance
API 609
Common design and testing basis for butterfly valves. Categoria, body pattern, seat design and exact edition must be identified.
ASME B16.34
Provides pressure-temperature and general valve design requirements where applicable to the offered construction.
API 598 / EN 12266-1
Shell and seat testing can be specified to the applicable market and project basis.
API 607 / ISO 10497
Fire-safe performance is qualification-specific and must be supported for the exact seat, seal and valve configuration.
Standards are supplied only when stated in the quotation and purchase order. À prova de fogo, emissão fugitiva, serviço azedo, cryogenic and PED requirements require a defined design and supporting qualification or documentation.
Aplicações típicas
| Indústria | Dever típico | Selection focus |
|---|---|---|
| Petróleo e gás | Process isolation and emergency shutdown | Fire-safe design, torque margin and leakage class |
| Petroquímica | High-temperature hydrocarbon and utility service | Seat stack, emissions packing and pressure direction |
| Geração de energia | Steam and high-temperature auxiliary systems | Thermal cycling, material strength and actuation |
| Marine and offshore | Utility, cooling and corrosive fluid systems | Duplex materials, external corrosion and gearbox protection |
Application examples are not a service approval. The end user or piping materials engineer must verify corrosion compatibility, pressure-temperature limits, emissions class, operating frequency and applicable regulations.
Inspection and supply documentation
EN 10204 3.1 material records and heat-number traceability when ordered.
Shell and closure/seat testing to the ordered standard with documented acceptance criteria.
Positive material identification and PT/RT/UT scope arranged when specified in the inspection plan.
Dimensões, marcação, operação, coating/cleanliness, packing and document dossier checked before dispatch.
Lista de verificação de RFQ
- Design standard, body pattern and face-to-face requirement
- Nominal size and pressure class or PN
- Corpo, disco, shaft, seal ring, assento, packing and bolting materials
- Required leakage class and pressure direction
- Fluido, design pressure, temperature and differential pressure
- Gearbox or actuator and fail-action requirements
- Fire-safe and fugitive-emission qualification
- NACE, PMI, EQM, witnessing and document requirements
Perguntas frequentes
What are the three offsets?
The shaft is offset from the seat centerline, offset from the body/pipe centerline, and combined with an angled conical sealing geometry. Exact geometry varies by manufacturer design.
How is a triple offset valve different from a double offset valve?
Triple offset designs add a conical sealing geometry that minimizes rubbing and supports engineered metal seating. Double offset valves commonly use resilient or high-performance seats and have different temperature and leakage capabilities.
Is the valve bidirectional?
Some designs provide bidirectional shutoff while others have a preferred pressure direction or different leakage performance by direction. Confirm the tested capability of the exact offered configuration.
Can it be supplied fire-safe?
Yes only when the exact valve construction has appropriate fire-test qualification. Material selection alone does not establish fire-safe performance.
What information is needed for actuator selection?
Provide maximum differential pressure in both directions, design de assento, fluid and temperature, operating time, frequency, fail position, power supply and required safety factor.
Request a triple offset butterfly valve quotation
Send the size, aula, body pattern, materiais, leakage requirement, pressure direction and actuation data for review.
