Butterfly valves have long been a popular choice in industrial applications due to their compact design, fast operation, and reliable flow control. But when you’re dealing with high temperatures, high pressures, or critical service applications, traditional butterfly valves just don’t cut it.
Enter the Triple Eccentric Butterfly Valve — an engineering marvel designed to solve the limitations of concentric and even double eccentric valves.
But what exactly is a triple eccentric butterfly valve? Why is it used? And how does it differ from other types? Let’s dive in and break it all down.
A butterfly valve is a type of quarter-turn valve that uses a rotating disc to regulate flow. When the disc is turned parallel to the pipe flow, it allows fluid to pass. When it’s perpendicular, it blocks the flow.
These valves are widely used in water treatment, HVAC, oil & gas, chemical processing, and more. However, traditional butterfly valves (like concentric or double eccentric) have limitations in extreme service conditions.
That’s where triple eccentric designs shine.
A triple eccentric butterfly valve (also called TOV – Triple Offset Valve) is a high-performance valve engineered to eliminate friction, withstand extreme temperatures, and provide zero-leakage shut-off.
The term "triple eccentric" refers to three specific offsets in the valve's design that reduce seat wear and ensure a tight seal.
Here's how the three offsets work:
First Offset: The shaft is placed behind the centerline of the disc seat.
Second Offset: The shaft is also off-center horizontally from the valve bore (pipe centerline).
Third Offset: The sealing surfaces (disc and seat) are designed in a conical shape, creating an angled geometry that allows the disc to cam into the seat without sliding.
The disc rotates into the seat without rubbing, eliminating friction.
Sealing is achieved through torque, not interference.
The valve provides a bubble-tight, metal-to-metal seal, even at high pressure and temperature.
Zero Friction between the disc and seat during operation
Metal-to-metal seal (often with hard-facing like Stellite or Inconel)
High temperature resistance (often > 500°C / 932°F)
High-pressure capabilities (up to 1500 psi or more)
Fire-safe design with fail-safe shut-off
Bidirectional sealing in many models
Suitable for tight shut-off (Class VI leakage)
| Valve Type | Friction During Operation | Seat Type | Seal Quality | Applications |
| Concentric | High | Soft (rubber) | Moderate | Water, low-pressure systems |
| Single Eccentric | Moderate | Soft | Improved | HVAC, utility services |
| Double Eccentric | Low | Soft or metal | High | Oil, gas, industrial |
| Triple Eccentric | Zero | Metal-to-metal | Very High | Steam, chemicals, power, refineries |
The materials used in triple eccentric valves are chosen to withstand harsh environments:
Stainless Steel
Carbon Steel
Duplex or Super Duplex
Inconel, Hastelloy (for corrosive applications)
Stainless Steel
Nickel-aluminum-bronze
Hard-faced with Stellite or Tungsten Carbide
Hard metal alloys (Stellite, Inconel)
Metal with elastomer backup (for resilience)
Optional laminated or resilient seals (in special designs)
The triple offset design ensures that the disc engages with the seat only at the very end of its rotation — like a door latching shut. There’s no sliding or scraping motion, which dramatically reduces wear.
Rotation (opening/closing): The disc moves freely with no contact.
Sealing: As the valve fully closes, the angled disc presses against the conical seat to create a tight, bubble-proof seal.
Triple offset valves can achieve Class VI leakage (zero leakage) — a requirement in critical process systems such as:
Chemical reactors
Steam and condensate systems
Natural gas transport
Cryogenic pipelines
Emergency shutdown valves (ESDVs)
Many of these valves also comply with fire-safe standards like API 607 and ISO 10497.
These valves are the go-to choice when you need ultra-reliable sealing and durability under tough conditions:
Oil & Gas
Chemical & Petrochemical
Power Generation (including nuclear)
Pulp & Paper
Marine & Offshore
LNG & Cryogenics
Steam
Natural gas
Acids and alkalis
Combustible fluids
Superheated water
Hydrocarbons
Longer Service Life: No rubbing means minimal seat wear.
Lower Maintenance Costs: Less damage, less downtime.
High Integrity Sealing: Excellent for dangerous or expensive fluids.
Compact Size: Smaller footprint compared to gate or globe valves.
Fast Operation: Quarter-turn design for rapid shutoff.
The quality triple eccentric butterfly valve is a high-performance solution designed for demanding environments where reliability, durability, and zero leakage are non-negotiable.
With its frictionless design and metal-to-metal sealing, it's the top choice for critical flow control in energy, chemical, and industrial systems worldwide.
So if you're dealing with high pressure, high temperature, or hazardous fluids, a triple offset valve may be exactly what you need.
