Low loss water check valve 1

[magnusrm]

Hi, i need a low loss check valve that can withstand pressures up to 100 BAR for use in seawater. Do you have any tips to a product serie i should have a look at? The pressure drop should be minimal and the waterflow is about 1200-2400 l/min, but i can use more than one valve.

 

[stanier]

http://www.noreva.de

valves are used extensively in desalination RO plants . They are available in super duplex materials. Their non slam characteristics make them suitabe for waterhammer mitigation.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/

 

[4bee]

magnusrm,

See info on Mokveld ultra low-dP axial non-slam check valves:

http://www.mokveld.com/en/7/products-of-mokveld-/products/4/axial-check-valve

Mokveld Valves BV is a company that developed their own unique axial non-slam check valve design exhibiting almost NO pressure drop. Extensive experience in non-slam check valves for critical service. Corrosion resistant materials are available.

Mokveld has its own unique low-dP axial design with special inner body stabilizing the flow. Others are not that reliable: NoReVa did not develop their own design, Schuck's design is not stable etc.

Regards.

 

[Chiuzzo]

Cameron Entech is another valid alternative if you consider they create a valve 'ad hoc' for each specific flow/installation condition. Body (PRP) can be forged also.

 

[stanier]

4bee,

Please explain about Noreva not developing there own design? Why do you not consider them reliable? The design came from Mannesmann Demag did it not? Wasn't the valve tested extensively at Delft Laboratories to determine the dv/dt vs Vr relationships?

I Hvae used many Noreva valves of different design and found that they are reliable so would like to know you experiences.

Why is the Schuck valve considered unstable? In what way is it unstable?

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/

 

[Chiuzzo]

http://www.c-a-m.com/forms/Product.aspx?prodID=f43b64f8-2939-423c-b65b-110fcb80c1c1

 

[Chiuzzo]

Hydraulic tests in Delft were carried out almost 50 years ago. You'd better start considering who invest time and resources on new products, R&D, etc. Take a look to the CAMERON website.

 

[stanier]

Chiuzzo,

Cameron & Mokveld are respected manufacturers of valves. I have never used Cameron check valves. For clean service I would look at their Z type. However there have been instances of this "type" of valve failing in service when there are small particles or corrosive substances in the fluid. The overhung disc with a single slide bearing and spring can compromised. (I am not suggesting they were of Cameron manufacture). Dirt can get between stem and bearing and seize the valve in the open position.

Noreva have this type of valve but limit their recommended use to small diameters. The larger valve type has a disc suspended on three leaf springs. It is self centering and can thus handle any small particles. They have long and short pattern types each with their own characterisitcs and Cvs. It is the valve of choice in the desalination industry being available in super duplex materials to Class 600.

Cameron did not have dv/dt vs VR data on their website but I expect a professional organisation like this would have it available on request.

In respect of Delft laboratories I believe that they have tested valves more recently. Any tests, even from 50 years ago would still be valid if the design had not changed. Similar test facilities exist at Utah State University.

The challenge in industry at the moment is that there are a large number of check valve manufacturers who copy some valve design from others and have no idea as to why, how, what engineering went into the valve. The data is just not available from these copiers. Accountants love them because they are cheap but at the end of the day it is the engineer who faces the judge not the accountant.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

http://waterhammer.hopout.com.au/

 

[gustorf]

Dear All,
Just to bring some light into the development of nozzle check valves:
Mannesmann Demag developed the nozzle check valve with ring disk / radial guide design 1935!
For small sizes below 12 inch, the central piston nozzle check valve was designed by Mannesmann 1955.
Mokveld copied the piston type design for all sizes 1968 with some design changes.
Cameron is the legal succedor of the Mannesmann designs since Mannesmann was sold 1999.
Noreva is a split-off based on former Mannesmann staff, they have developed and intensively tested their valve performance at Delft Hydraulics institute (Last time 2007 - not 50 years ago)
The question is: Do you want a reliable, well established and tested valve with thousands of installations world-wide? Than you may look for Mokveld or Noreva.
Do you want a valve of nice R&D pictures with a questionable design (central piston combined with ring disk) that hasn't been independantly tested?
Than look somewhere else.
Schuck to me is not a real nozzle check valve as the guiding system is a simple guiding cross without a nozzle.