Does pressure measurement for Hydrogen service need any special type of capsule or diaphragm? Can we not use the same SS316 diaphragm Pressure Transmitter for Hydrogen service also?
I have a typical application in which rosemount transmitter with ss316 capsule is working sound for the last 4 years. i don't think there should be any problem in your case too. Its better to use an integral orifice type DP transmitter if you are going for flow measurement in hydrogen service.
good Luck
Yes it does require special material & use
316ss L , Which reduces the permiability of H2
in SS.If you use conventional 316ss than the
life of the diaphragm is about 7 years.
I came to know through a seminar recently, that for Hydrogen service, the wetted part should be Post Weld Heat treated (PWHT). Is this a standard practice for normally available transmitters or this has to be done specially for Hydrogen service?
The pressure measurement for Hydrogen service need special considerations about diaphragm material? By high static pressures ie.around 70-80 bar Hydrogen diffuses through a SS316/SS316L membrane. The transmitter will work forever as long as the static pressure is constant. By low pressure ie by servicing, calibration etc. the measuring membrane will burst caused by the interior built up static hydrogen pressure.
Problem can be eliminated by using gold plated
membranes...like Sitrans P DSIII with gold plated stainless membrane as standard option.
SS 316 can be used effectively for H2 application because of it's low permeation rate,but it's permeation also depends upon the pressure,temperature & concentration also.If the pressure & temeprature is high hydrogen atom will collide with each other because of high kinetic energy & dissociate in to hydrogen ions which can penetrate through membrane inot the fill fluid causin the failure.
Inorder to avoid this the best & safe option is to go for gold plated diaphragm.Howevere the option is costly.
Does it matter on which side the gold layer is added?
(We have condition in which the gold layer vanishes in about a month; probably because of Hg and/or HCN).
