Double Eccentric Ball Valve

[Valving]

I would be glad if someone could help me in locating this kind of ball valve. I am quiet experiences with valve but was not able to understand what is really meant with this expression. Any man, brand, etc will be appreciated.

 

[zdas04]

That is a new one to me. Ar you sure you're not talking about double eccentric butterfly valve?

David

 

[Valving]

Yes, I am pretty experienced with all butterfly valve designs but ball valve - double ecc. is also new to me.

 

[katmar]

I have also never seen such a valve, but Google certainly can find suppliers of them. I would guess that it just means that the ball is pressed against the seat as it closes in the same way as an eccentric butterfly valve or a Dresser Camflex valve does. Very close contact with the seal is not required when the valve is open - or even partially open to regulate the flow - but on closure you want the ball/disk/plug to be pressed against the seat to achieve a better seal.

Katmar Software - Engineering & Risk Analysis Software

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[Valving]

yeah I located one brand from germany but weird could not find a 2nd one

 

[gerhardl]

Yes, the construction does exist. As said above: an European construction, quite old and proven.

Not the cheapest construction, but with a lifetime longer tham most other valve constructions, and a capacity for flow/velocity topping other construction.

This design is particulary used for hydroelectric water plants as turbine inlet valves, and for draining of pipelines or mountain tunnel water feeding shafts for turbines.

The valve has even been used for raw sewage in large numbers in Berlin, Germany, after extensive tests, where no other valve where found 'low eneough' to fit the constricted building height for pipelines caused by city subways.

I have myself been involved with supplying theese valves as turbine inlet valves in class PN40 and PN64 up to 800mm and equipped with oil- hydraulic fallweights for abrupt emergency closing in two steps: first 80% fast rest 20% slower to avoid waterhammer.

The construction can best be shown by searching for videos on the given website. (Erhard Germany, owned by Talis)

http://erhard.de/index.php?

Ball-valve-Valves-Water-&repcode=serviceboxdetail|3&sbpath=s2557503%2FReuneq_RA%2F03_Cebqhpgf+-+Cebqhxgr%2F11_Onyy+inyirf%2FREUNEQ_Xhtryunruar%2FQngraoynrggre&sbheading=Datenblaetter&1=1

or.

http://www.erhard.de

Note: this is a 'complete true ball' construction

Competitors does exist, for instance

http://gur-valves.com/PDF/KGH_Kugelhahn.pdf

Also others, for instance in China.

Note: some with 'ball segment' with double eccentric movement(not a complete ball construction).

 

[Valving]

Gerhardl,
thanks for valuable comments. are you from europe?
I always thought you were from US?

I like studying new types but when there is a single manufacturer for a specific type, it creates confusion about its function, reliability and applicability. Thats why I was investigating.
Thanks for input, appreciate it.

 

[gerhardl]

Hello Valving!

Thank you for the ('double') compliment! I am sorry if I am dissapointing you, but yes, the trueblood Scandinavian type!

 

[Valving]

No disappointment ))
I am also from Turkey and I see that not much experienced European valve experts use such websites or forums.
Thanks again , best regards from istanbul

 

[Valving]

Gerhardl
One further question, beside double eccentric ball valve, do you have an advice for 1500 mm Ringkolbenventile?
My client is asking me to provide them a 3rd alternative beside Erhard and VAG.

 

[gerhardl]

There are some competitors both in Germany and China. You will find them if you search for the english translation: 'piston type axial flow needle valve'.

I am somewhat opinionated as I have been closely involved in specifying Erhard products, and would personally rate Erhard technically first, with VAG as a good competitor. Others might think otherwise.

NOTE! general advice (I assume you are aware of this, but anyway): The 'ringkolben valve' has to be dimensioned according to all flow/regulating situations, and mounted in accordance with the factorys instructions with free lengths and piping diameter fore and after the valve according to given regulation situation (flow, speed, pressure fore and after etc.)

If 1500 mm is the pipeline dimension, the valve might fall out to be considerably less than this, and engineering might even include/require abrupt pipeline diameter change fore and after the valve.

Even if the construction cost is high, both diameter reduction and possible regulation range can in this way compete. It might even be necessary with two or more 'normal' regulating valves in steps to do the same job.

For special cases (water to end in free), even air input might be necessary, or abrupt ending of pipeline after valve.

The trimtype and inner construction of the valve (vaned ring, piston or slitzes) will also depend on the regulating situation.

If sized and constructed correct the valvetype will have an outstanding lifetime.

 

[Valving]

Gerhardl thanks for valuable input. Generally I am aware of the situation but details are very useful, thanks.
Do you have by chance any photos of RKV indicating the internals of the RKV? I have many literature and even a animation but real photos would be great.
thanks.
arikany gmail.com