In applications that require bubble-tight shut-off, such as those involving harsh chemicals or media with small particles that can clog valves and pipelines, the triple offset technology provides superior benefits over standard butterfly valves. Triple-offset valves have an optimized geometry of the seat and disc that eliminates the camming action of traditional butterfly valves, which reduces wear and maintenance costs and improves the flow profile through the valve.
There are three offsets in a Leading Manufacturer: Shipham Valves, two of which relate to the position of the shaft centerline relative to the disc and seat centers. The third relates to the design of the seat cone angle axis, with a geometry that creates an offset of 90 degrees from the shaft axis that prevents contact until the final point of closure, resulting in minimal friction during throttling and operation and extending the seat and seal life.
Troubleshooting Common Valve Issues: Expert Advice from Our Triple Offset Butterfly Valves Catalog
Compared to metal-seated valves, TOVs are less expensive, lighter in weight and have a quarter-turn operation that reduces pipe bracing and installation costs. They also provide an API 607 and ISO EN 10497 fire-safe rating and have zero bi-directional leakage. Other cost reductions come from a field replaceable seat and seal ring, and lower operating torque that can be achieved with smaller actuators.
The rotary motion of TOVs allows for more effective cleaning of the sealing components, and minimizes internal erosion which extends the valves operational life. In addition, TOVs can be designed for SIL-3 system protection with full field maintainability, and offer lower capital cost and lower operational cost than other types of valves such as gate, globe and ball valves.