Pressure compensated drum level


Thread Starter


I am installing my first drum level control for a stoker boiler that operates at 180psig. What is the best way to calculate the bias for the pressure compensation?


Look at "DRUM LEVEL CONTROL" july-02-2000
<[email protected]>. There,
you will find the basics of that loop.
In your expression "Pressure compensated"
you must have a three elements control
algorithm. What you call 'Bias' is
probably 'ratio'. Let me know more.
Friendly <[email protected]>

Arnold Dillon

The "bias" calculation as you refer to it requires that you just follow the saturated water table for the shift in specific gravity between cold condition and the hot condition. In this case the hot condition in 180 psig and there won't be enough of a shift to really worry about. When you start working on 1000 psig boilers, or something of higher pressure, then you need to worry about this compensation.

Arnold Dillon
I.C. Thomasson Associates