V-notch ball vs regular ball 1

[dragos12]

Dear Gents, may I receive your comments
about reason to select V-Notch ball valve for an on-off
application instead of a regular one?
V-notch would have longer lead time and cost.
However maybe operation of it can be easier, less-torque etc.
Thanks for sharing.

 

[GBTorpenhow]

The V notch is there to improve throttling characteristics, in a pure on-off application there wouldn't be any reason that I can see to use a V notch ball.

 

[bcd]

In some situations, the V-notch valve is lower cost than a full ball valve. On occasion they are used for on/off service. The primary reason is cost. The bare stem v-notch vale can be lower cost, especially with metal seats. May have less parts and lower torque to operate, so a smaller actuator. Another benefit of the v-notch valve is there is no cavity to trap media like there is in a ball valve with 2 seats. So build-up of pressure in the cavity is not a risk.

 

[LittleInch]

V notch opening torque would be much the same as its the seal pressure against the ball which dictates this.

Evan at full open there is a restriction in flow.
The valves only seal one way.

You would only select one if you had a high DP and needed to open the valve slowly or use it as a Control valve.

Normally not used for straightforward isolation but you could use in place of a globe or plug valve.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[dragos12]

Thanks Gentlemen,
do you think that solid content in the fluid may be in favors of v-ball or vice versa?

 

[LittleInch]

"Solid content" is rather vague, but no standard valve likes abrasive solid content.

Wouldn't make any difference to me between those two.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bcd]

High solids content could erode the downstream seat in a traditional ball valve when the valve operates. During operation, the downstream seat is exposed directly to the media flow. This is avoided with a v-notch type ball valve when the seat is on the upstream side of the valve.

But keep in mind that "solid content" is a very vague description. Most important is if there is proven history of use in the application. Only then can you be confident that it will work.

 

[LittleInch]

Scoring / abrasion of the ball is a major issue as well. This would apply just the same between the two if used as an on off valve.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[gerhardl]

I agree with all answers above.

However: A selection af any valve for any purpose is always depending on the exact conditions, well known to all: Fluid with chemical description, all additions and contaminations, pressuere, temperature, flow, behavior at emptied valve at surrounding temperature), pressure, regulation or on/off, number of operations per time, opening/closing time, pipeline size, selected valve size, price, total number of valves, actuation type, cost over lifetime including operational and replacing/repair cost/time etc. etc.

General advice:
For common fluids, pressure classes and 'normal' sizes, common ball valves tend mostly to be the best choice.
Steam and/or higher pressures and dimensions: V-notch to be evaluated, but not always the best.
Fluid with abrasion: Always a problem. Ballvalves not always the best solutions, V-notch to be considered, cermaic lining (costly) sometimes practical, sometimes gatevalves or special gate valves (espcially for high temperatures, pressures and dimensions) are the best.
Some special cases: Water at high pressure/dimentions(hydroelectrical power plants) or waste-water at larger dimensions (above 500mm) double eccentric ball valves (costly). Other valve-types also widely used.

Conclusion: more details needed for best advice.