Do you know a multi-hole orifice valve? 2

[let0083]

Excuse me, I have a question.
Do you know a multi-hole orifice valve?
What is the company that you have been used it?

 

[JLSeagull]

Many anti-cavitation and noise control valves use multiple pressure drop paths.

One company, Micon used to have a digital control valve to also measure flow with sequencing of multiple orifices. I think it was PSI Micon - now part of ICS Triconex. I am not aware of the valve being in production.

 

[JimCasey]

Embellishing what JLSeagull said:

Universally,companies that offer globe control valve will offer a multi-hole modification for either noise-control or cavitation control.

Commonly the multihole unit is a cage with sometimes hundreds of holes drilled in it.

For noise reduction, the flow is from the center outward, and the holes are very small-on the order of 1 mm diameter. The characteristic frequency increases as the hole size decreases, so the noise generated by the very small holes is above the frequencies we hear well. Hole-spacing is also intended to cause acoustic cancellation at the characteristic frequency.

For cavitation control, the flow is radially inward. The holes are typically larger-around 3mm. Cavitation happens, but the jets meet in the center of the cage and the bubbles collapse in free volume where they do not cause damage.

Multi-stage cages are also used both for cavitation prevention and for noise reduction. The cages are concentric and provide both numerous stages of pressure reduction, but also tortuous paths to control velocity.

Multi-hole trims must be used with clean processes. If there are particles, they make highly efficient(but difficult to clean) strainers.

 

[JLSeagull]

Please clarify your question to assure that we respond in an appropriate manner. Our responses apply to control valves.

Neles and a few others offer severe noise reduction trim in ball valve patterns. Emerson a.k.a. Fisher, Dresser a.k.a. Masoneilan, Flowserve a.k.a. Valtek and others manufacture noise and cavitation control valves for many applications. Specialty companies such as CCI offer the really tricky paths on many stages for "CLEAN" service with severe noise. Some noise control valves also use plates or noise attenuators downstream of the valve. Fixed restrictions can work well but only around the design flow rate.

 

[Ashereng]

JL gives several good example, if my interpretation of "multi-hole orifice" valve is correct.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[stanier]

CCI manufacture a tortuous path valve for severe service. This is more than for noise control. The valves are used in power stations for blow down.

Geoffrey D Stone FIMechE C.Eng;FIEust CP Eng

http://www.waterhammer.bigblog.com.au

 

[let0083]

Thanks for many responds.

I need information about multi hole orifice valve,
gate type (like a MONOVAR or FLOTUS valve)

 

[JimCasey]

OH!

Those are not very common. In the US there is Jordan valve which is very similar in principle. They use a sliding grate with slots instead of round holes.

http://www.jordanvalve.com/

Not a big player in the overall scheme of things, but they have been around for a long time. There is a challenge to get good resolution in such a valve because of the very short stroke between when the holes are closed and when the holes are aligned for full flow. Another consideration would be the friction from the metal plate sliding on the stationary plate. These challenges can be overcome with attention to the engineering. Dissimilar metals, oversize actuators, all help. Jordan even offer regulators in this configuration, so they must have done a good job at reducing friction.

The theoretical benefits and limitations would be similar to those discussed earlier for cage-type valves. Reduced noise , resistance to cavitation, but Reasonably small holes to catch foreign objects, bearing surfaces exposed to contaminants in the flow.

 

[let0083]

Thank Jim!!
It's good news for me !!

 

[TD2K]

You might want to look at Varco Best also.

 

[Ashereng]

Hmmm.

As JimCasey says, these are not very common. I have never ussed or specified one.



"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?