Design Standard: API 609, MSS SP-67, MSS SP-68, BS 5155
Face to Face: API 609, ASME B16.10, BS 5155, EN1092
End Connection: DIN PN10/16/25, ANSI B16.1, BS4504
Inspection and Test: API 598
What is a Triple Offset Butterfly Valve?
Triple offset butterfly valves (TOBV) are available in three different sets. Two offsets are in the center and a third is on the seal face, forming a conical shape for the disc and seat. Triple offset valves are used where a gas tight seal is required, the system is at high temperature and a zero leakage hard seal is required. The first offset is supplied to the central axis of the sealing face, on which the disc rotates 360 degrees around the central axis, providing a seal by deforming the soft seal, resulting in total friction. The second offset refers to the position of the axis relative to the center line of the hole. During operation, it creates a CAM action that lifts the seat away from the seal, creating friction during the first 10 degrees of opening and the last 10 degrees of closing. The third offset is the geometry of the closed primitives. Each seal element is machined to a tapered offset profile, forming a right taper. This ensures frictionless stroke throughout the working cycle. Contact is made only when the 90° Angle acts as a mechanical stop on the final closing point; This will cause the disc seat not to overshoot. When these triple offsets are supplied together, the valve provides a continuous sealing face with minimal wear between the sealing faces and provides a lasting seal throughout the life of the valve. Additionally, disc adhesion and bonding are reduced and less operating torque is required due to disc’s optimized seat Angle.
Classification by Connection Type
Based on the connection there are different types of Triple offset butterfly valves.
Wafer type ends.
Lug type ends.
Both flanged ends.
Butt-welded types end.
Wafer Type: The wafer type triple offset butterfly valves was built to keep a tight sealing, protecting against bi-directional pressure differentials, to prevent any backflow in devices that were built for uni-directional flow. This is done by the use of a tightly fitted cap, such as an O-ring, gasket, precisely machined, along with a smooth valve face on the downstream and upstream parts of the valve. Lug Type: The lug type triple offset butterfly valve configuration is similar to the 3-piece ball valve in which one end of the pipeline can be replaced without impacting the other side of the valve. This can be achieved with threaded inserts, flanges, and two sets of lugs (bolts) that do not use nuts so each flange has its bolts. It is also important to remember that you do not need to shut down the whole device to inspect, clean, repair, or replace the lug butterfly valve. Flanged End Type: The flanged type eccentric butterfly valve has a flange at both ends of the valve to be attached with pipe flanges. This type of end connection is used for the very large size of butterfly valve. Welded End Type: The welded end type butterfly valve is used where system is under very high pressure. These types are generally used for small size butterfly valves.
How Does Triple Offset Butterfly Valve Work?
The triple offset butterfly valve does not operate like a traditional butterfly valve, which while turning of the lever, turns sideways to allow the media to pass, like handwaving. The triple offset type works like a globe valve, where the disk moves a bit like a cone, going up and down. A strong seal occurs as the cone moves to become a circle. There is no drag when the seat comes into contact with the disk due to the angled positioning of the disk in relation to the surface.
Application & Benefit of Triple Offset Butterfly Valve
Triple Offset Butterfly Valves are important for applications where bubble-tight sealing is needed. In some applications, bubble-tight sealing cannot be accomplished by using triple offset butterfly valves. Some processes do not adapt themselves well to conventional butterfly valves, such as applications containing harsh chemicals or mediums with small particles susceptible to clogging valves and pipes. In such systems, Triple Offset Technology gives superior advantages where cam action and right-angled conical sealing ensures that the metal seal elements will never come in contact until its final degree of closing. Here metal to metal sealing provides bubble-tight shutoff which results in no leakage performance. Friction-free stroking is available throughout the cycle which allows the operation with low torque and extends the valve life. Valve has no cavities between the sealing elements due to which clogging is eliminated which results in low maintenance and in turn extends the valve life.
The triple offset butterfly valve (TOBV) meets the demanding needs for two-way shutoff to deliver high quality isolation for big range of applications includes power and steam, tank and terminal, petrochemical, upstream production, refining, and gas process operations. Rigorous testing and advanced engineering
As a member of the verified Cameron quarter-turn butterfly valve portfolio, every triple offset butterfly valve (TOBV) undergoes arduous qualification and testing processes that simulate the valve life cycle. That’s however you recognize it’s been designed and built with the producing excellence and commitment that distinguish all Cameron product lines. Worldwide footprint and support Our world support and strategic networks brings the triple offset butterfly valve (TOBV) wherever it’s required, once it’s needed—fully designed, tested, qualified, and backed by Cameron, the leader in valves manufacturing.