Monoflange qualification 1

[Eng.Husky]

In the process applications is a high response speed required for the most control applications. One of the variables that affect the response time is the volume and the distance between process and pressure sensor. This why a monoflange is an interesting solution to connect the pressure sensor to the process.



If we look at the qualification of the monoflange then we will find out that is impossible to design the monoflange according to asme b16.34, because asme b16.34 covers valves with:

Flanged end (monoflange has not a flanged end)
Threaded end (monoflange has not a threaded end)
Welded end (monoflange has not a welded end)



It’s only possible to determine the external and internal wall thicknesses of the monoflange according to asme b16.34, but this does not mean that the monoflange valve is designed according to asme b16.34

It’s also interesting to know that all monoflanges has been designed to be connected to an asme b16.5 flanges.

My question:

Why would someone use a monoflange valve that is not qualified in process applications?
Are there any standards to design a monoflange?



Thanks in advance for your time.

 

[Andrew ONeill]

You can qualify it by during burst tests, well you can for B31.3. It wont be qualified to B16.34, but can be used in the relevant piping standard (I'm familar with B31.3). B31.3 talks about "unlisted components" section 304.7.2. I would be surprised if the supplier didn't already have some documentation about this.

Andrew O'Neill
Specialist Mechanical Engineer
Australia

 

[Eng.Husky]

Thank you very much for your relevant information’s

I learned last days that is also possible to design a monoflange according to ASMEB16.34, by using paragraph 6.7 in ASME B16.34 for wafer or flangeless valves. The monoflange valve appears to be this type of valve and if it complies with the requirements of paragraph 6.7, then it is within the scope of B16.34.

Ali Al-Saadi
Mechanical Engineer
The Netherlands