Engineering guides: API 609 butterfly valve guide · API 598 tested butterfly · Butterfly standards hub
Triple Offset Butterfly Valve Metal Seated
Butterfly Valves

Triple Offset Butterfly Valve – Metal Seated (TOBV)

The triple offset butterfly valve represents the pinnacle of butterfly valve technology. With three geometric offsets creating a conical sealing surface, it achieves zero-friction metal-to-metal sealing suitable for the most demanding applications including high pressure, high temperature, and cryogenic services.

The Three Offsets Explained

1st Offset: Stem behind disc centerline
2nd Offset: Stem offset from pipe centerline
3rd Offset: Conical seat angle (typically 3-5°)
This creates zero friction during rotation - contact only at final closing moment.

Key Standards & Certifications

API 609 ASME B16.34 API 607 Fire-Safe API 6FA BS EN 593

Size: DN50 - DN1500 (2" - 60") | Pressure: Class 150-2500, PN10-PN420

Request Enquiry WhatsApp Download Datasheet

Materials of Construction (MOC)

Component Material Specification
Body & Bonnet Ductile Iron (ASTM A536 / EN-GJS-400-15)
Stem / Spindle SS 410 / SS 420
Seat / Trim EPDM / NBR / Bronze

Technical Specifications

Parameter Specification / Standard
Manufacturing / Design Standard EN 1171 / AWWA C509 / BS 5163
Testing Standard API 598 / EN 12266-1
Pressure Rating PN16 / PN25

Frequently Asked Questions

What is a triple offset butterfly valve?

A triple offset butterfly valve (TOBV/TOV) has three geometric offsets: 1st offset - stem behind disc center, 2nd offset - stem offset from pipe center, 3rd offset - the seat cone angle creates a conical sealing surface. This design provides metal-to-metal sealing with zero friction during operation.

What is the 3rd offset in a triple offset butterfly valve?

The 3rd offset is the cone angle of the seating surface. The seat and disc sealing surfaces are machined at an angle (typically 3-5°) to create a conical shape. This geometry ensures the disc contacts the seat only at the final moment of closing, eliminating friction during rotation.

Why is triple offset butterfly valve called zero friction valve?

Due to the conical seat geometry (3rd offset), the disc does not contact the seat during 99% of its rotation. Contact occurs only at the final moment of closing. This eliminates rubbing friction, reducing wear and torque requirements while extending valve life significantly.

What is the maximum pressure rating for triple offset butterfly valve?

Triple offset butterfly valves can handle pressures up to ANSI Class 2500 (approximately 420 bar/6000 PSI) depending on size and material. They are suitable for the most demanding high-pressure applications in oil & gas, power generation, and petrochemical industries.

What is the temperature range for triple offset butterfly valve?

Triple offset butterfly valves can operate from cryogenic temperatures (-196°C for LNG applications) up to +815°C (1500°F) for high-temperature steam and thermal oil. The temperature range depends on body and seat materials selected.