Triple Offset Butterfly Valves And Their Advantages

Jul 13, 2023 | News


Triple offset butterfly valve features a unique design that provides an alternative solution for applications where tight shut-off, zero leakage and long service life are crucial. They accomplish this through a “tripling” of the standard disc offset found in conventional butterfly valves.

The triple offset design of these butterfly valves enables significant improvements in shut-off capability, reduced torque requirements, increased resistance to vibration and cavitation, and longer service life.

triple offset butterfly valve

How Triple Offset Butterfly Valves Work Properly?

In a standard butterfly valve by triple offset butterfly valve factory, the disc is offset from the centerline of the valve body to improve sealing and shut-off. This is known as a single offset design. China triple offset butterfly valve takes this one step further. They feature a disc that is offset in three ways relative to the flow axis:

• Radial offset – The disc is offset radially outward from the center of the valve body. This delays the point of contact with the seat for improved shut-off.
• Axial offset – The disc is offset along the axis of the valve shaft. This extends the sealing line with the seat for a tighter, more secure seal.
• Angular offset – The disc is offset at a slight angle relative to the normal axis of rotation. This applies a wiping action when seating for a dynamic seal with no dead space.

The result of these triple offsets is a valve that can achieve zero leakage and is inherently better at vibration resistance, cavitation erosion resistance, and fatigue resistance due to the more advanced sealing design.

Benefits Of Triple Offset Butterfly Valves

The additional complexity of triple offset butterfly valves translates to a number of key advantages over traditional butterfly designs:

• Zero or ultra-low leakage – The triple-offsetting action provides an extended sealing surface and wiping action for a dynamic seal with almost no leakage.
• Longer service life – The design is less prone to vibration, cavitation erosion and fatigue failure due to a more optimum stress distribution and reduced number of stress-concentration points.
• Easier maintenance – The disc can still be removed and replaced without disassembling the pipeline, similar to standard butterfly valves.
• Bi-directional sealing – The triple offset design provides sealing in both flow directions for applications that require reverse flow capability.
• Less torque required – The delayed point of contact means less torque is needed to seal the valve, reducing actuator size requirements.
• Higher cy clearage – The more gradual sealing surface results in lower friction and wear, enabling a greater number of open-close cycles before maintenance is needed.

Common Applications For Triple Offset Butterfly Valves

Due to their inherent advantages for tight shut-off and regulating critical flows, triple offset butterfly valves are specified for:

• Pulp and paper processes – Controlling and isolating flow of pulping liquors, white and brown stock, and steam.
• Power plants – Isolating flows of boiler feedwater, condensate, cooling water and various chemicals.
• Oil & gas pipelines – Flow control of hydrocarbons and related fluids in transportation and production applications.
• Wastewater treatment plants – Isolating and throttling flows of sludge, effluent and plant chemicals.
• Pharmaceutical processes – Regulating critical flows in clean room environments with zero contamination tolerance.
• Semiconductor fabs – Tight shut-off and minimum dead space help maintain high purity of process gases.
• Food and beverage – Controlling liquid flows while meeting 3A and USDA standards for zero leakage and no dead spaces.