Effect of passing seals on orifice plate reading?

[Iradah]

Hello,

What is the effect of having the seal around the orifice plate passing?
we recieved an orifice plate with double volcanized seal around it. the seal was rectangular so our instrument technician tried to make it round and then installed it? what if the seal after this modification is passing? how can the reading of the orifice plate be affected?

 

[zdas04]

The dP (and therefore the indicated flow) will be low. The worst I ever confirmed was a 17% error in flow (so it was closer to 41% error in dP). I had a couple of cases where replacing a seal ring could have given me a bigger improvement, but other things happened in the system and I couldn't confirm that the whole amount came from seal ring leakage. I've seen small leakage caught early be a couple of percent low, but the tendency is for the rubber to rapidly erode and jack the error up quickly.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[Iradah]

Thank you zdas04. This is the answer I was looking for.