What is triple eccentric butterfly valves? 5

as titile and what is the benefit of this valve?

 

[cranekiran]

Well!

Triple eccentric means:-

1)First eccentric is the offset between the shaft centre line and the disc trunnion centre line.

2)Second eccentric is the offset between the body centre line and the disc centre line.

3)The third and the most important is the eccentric in the sealing(multiple) itself such that if you draw a imaginary contour line between the sealing shape vs the body centre,It becomes a cone with one side flat on surface.(I hope my words are clear enough to make you understand).

The reason for this shape is because it gives better sealing ability for the valve.eg:- Fire safe valves are triple eccentric valves which are also called pyrogenic valves.The sealings are multiple in nos. and together they form a pyrogenic shape therefore this sealing is also called pyrogenic sealing.

Cheers!

 

[atad]

In addition to the above they also operate at relatively low torques. This means that the actuator driving the valve (if automated) will be smaller and therfore cheaper!

 

[NGiLuzzu]

In addition to the above information about what Triple Eccentric Butterfly Valves are and low torques, I would suggest that the benefits are in terms of weight, overall dimension and costs, if compared with Ball or Globe valves.
Regards, 'NGL

 

[Hmmmmm]

Further to the triple offset (triple eccentric) butterfly valves, this geometry allows a valve construction with rigid sealing parts, i.e. metal seat which is inherently fire-safe, and cryogenic, and exhibits drop-tight (bubble-tight) sealing capability.
In other words, you can reliably seal a triple offset butterfly valve against high pressures and high temperatures. The valve can be constructed from materials that will hold tight continuously against hundreds of psi pressure at temperatures in the 1000 degrees F range...

 

[V150]

IN ADDITION TO ABOVE YOU CAN SAFELY CALL IT AS A POSITIVE SEGRAGATION VALVES. THIS DESIGN TOTALLY AVOID PRODUCT MIX UP
SHRI

 

[Burdy]

V150,
Be careful a lot of Triple pffset valves are not fully rated in both directions in all applications!

 

[TangoCleveland]

The disc size and hardware in the valve bore can reduce flow area relative to full port ball valves, especially in smaller sizes.


Larry

 

[NGiLuzzu]

About metal-seated triple-eccentric butterfly valves, you can also see Thread408-64692 in this Forum...
Bye, 'NGL

 

[Burdy]

I believe that two things have been missed out which need clarification:
a)Triple offset valves do not have sealing surfaces which rub together, as the principle is to bring two cones together one inside the other the rubbing is eliminated.
Therfore the wear of the sealing surfaces is stopped unlike double offset valves where wear is significant.
b)Triple offset valves are 'torque seated' although they may have very low torques to operate the valve in the 'running' cycle(just after opening and just before closing), the torque is high to seat/unseat the disc.
This is because the valve 'sealing cones' are being pushed together and need to be 'held'. Imagine trying to push a countersunk screw into a matching hole, you need to 'hold' it in position. If the angles on the cones were very small then the disc would stick and never open i.e. taper pin
That should make it clearer.
B