level gauges

S2010, This sounds like a student homework question, which is not allowed on this site. If you are not a student please provide more details in your question to convince us it is worth answering.

In my company we have programe which contain alot of tasks and question and we must do it, So these question is from my programmes, for the first question i have the answer but i want to make sure if its correct or not (really I'm not student)

***Explain possible causes for level gauges to give false readings and how this can be corrected.
Answer:-
Possible Causes
1- Choking of level troll legs (usually the lower leg) due to sediments/sludge.
(Corrected action is:- Servicing of level troll is required.)


2- Stuck up Float: Float may get stuck in the level troll due to hydrate formation, or solid deposits. ( Corrected action :- servicing of level troll is needed.)

3- Loss of Glycol in the Glycol pot, where used.
(Corrected action :- Refill the glycol pot.)

4- Leaks from the connections on level troll. This will affect DP type transmitter due to false DP reading, and hence the level reading

Hi,
This is not a student question at all.
It is such an important subject that Norman Lieberman has devoted a whole chapter about this in his new book "Process Equipment Malfunctions".
The main reason for the discrepancy between the real level and the level gauge indication is density.
In short, the density inside a distillation tower for example is lower than the density of the clear liquid in the instrument, because of foaming effect. As a result the real level is always higher than the indicated level.
More causes are discussed in the book.

"We don't believe things because they are true, things are true because we believe them."

It can be because of the density difference between the fluid inside the vessel being measured and the fluid in the gage and its connections whether or not foaming is occuring.

rmw

Thanks alot for helping ( answering) and i will look also in the book "Process Equipment Malfunctions".