L
Hello everyone,
In the past I have been told that the correct way of using the valve manifold for differential pressure transmitters is to firstly open the equalisation valve before isolating the HP and LP line from the system.
We were told to do this because, if an instrument has been labelled wrongly etc and someone is fast enough in the control room, you can be contacted to reinstate the transmitter by closing a valve. If you isolate and lock off the tapping lines then it takes much more time to do this and if the site goes down it costs a lot to get it back up and running again.
I have been told however after that this could damage the transmitter, but I do not see how. I have created a pressure equilibrium and if anything protected the instrument more. The only thing that I can see happening is in certain circumstances liquid could fill the LP leg from the HP leg which would have to be drained before commissioning.
What do you think? I want to get my facts right before writing a procedure. I would also like to understand how I can damage the instrument by using my method!
Thanks
In the past I have been told that the correct way of using the valve manifold for differential pressure transmitters is to firstly open the equalisation valve before isolating the HP and LP line from the system.
We were told to do this because, if an instrument has been labelled wrongly etc and someone is fast enough in the control room, you can be contacted to reinstate the transmitter by closing a valve. If you isolate and lock off the tapping lines then it takes much more time to do this and if the site goes down it costs a lot to get it back up and running again.
I have been told however after that this could damage the transmitter, but I do not see how. I have created a pressure equilibrium and if anything protected the instrument more. The only thing that I can see happening is in certain circumstances liquid could fill the LP leg from the HP leg which would have to be drained before commissioning.
What do you think? I want to get my facts right before writing a procedure. I would also like to understand how I can damage the instrument by using my method!
Thanks