BUTTERFLY VALVES
Packing adjustment bolting is clear of insulation area
Integrally cast ISO 5211 mounting pad
No bolting on flange sealing surface
Extended neck accommodates insulation
Fully rated , bidirectional dead-end service
Stub shaft maximises K v and range of control
Figure 2 : A high-performance butterfly valve body should include standard take-out dimensions , allow direct actuator mounting , and maximize valve capacity when fully open .
rings for support , and specially designed seal rings that incorporates engineered wires and gaps to allow the seal to self-adjust with each stroke . Such a design enables the valve to maintain zero-leakage performance over many more valve cycles , and it greatly extends valve life to reduce lifecycle cost
Another key feature of these types of valves is the packing arrangement . The latest environmental standards require many valves to achieve and maintain very low levels of packing emissions . Historically , this level of packing performance required a highly compressed packing , which
Figure 3 : High performance valves should be designed with maintenance in mind to allow typical repairs , such as a seat or packing replacement , without valve disc or stem disassembly .
accelerates wear of both the packing and stem , while hampering valve movement . This limitation can be overcome by utilizing live-loaded packing washers and advanced sealing ring material combinations suited
36 Valve World November 2024 www . valve-world . net