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.