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What is a PT square root function(PT?) use in fucntion block diagram?

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don121don121

Electrical
Oct 1, 2009
3
What is the (PT?) function. It is my first time to do the functional block diagram for industrial plant related on instrument control. It very difficult fo me to understand the diagram. any related response will be appreciated, thanks... am newbie here...
 
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Possibly a Pressure Transmitter that measures the pressure difference across a flow element - orifice plate maybe - the Flow is proportional to the square root of the Pressure difference. Normally that would be an FT not a PT.
 
hello francis, actualy in legend this (PT?)correction is pressure teperature correction. i just cant understand the fuction cause its my first time to do this. Im working in a japanese company and they give me this job as a training if i can do it. in diagram there is two pv input to this symbol one is from flow transmitter which is whirpool type as i translate the japanese to english i dont know the tech term, and the other one is from pressure transmitter. And then the output is to control the control valve automatic and manual from DCS. Im willing to send you a diagram and flowsheet if you want to help me. Thank you very much i really have to know this job.
 
'whirlpool' probably means conventional 'vortex' technology flow meter.

I suspect the combination of measurements, flow rate, temperature, and pressure constitute a gas flow computer.

Gas flow rate from a flow rate meter is typically temperature and pressure compensated to achieve an inferred mass flow measurement.

Dan
 
Thank you Dan, i`ll study how vortex works.
So you mean my statement above is a flow meter compensated with pressure transmitter as a correction to get iferred mass flow rate. Actually the pressure trans. is installed in steamheader from boiler then theirs a pipe towards steam acummulator where the flow trans and control valve installed respectively. What is the typical or facts ratio of these FT and PT process variable(PV) to Output Manipulated Variable (MV) towards control valve. Thank you very much its getting more clearer to me.
 
You should find many articles on steam drum level and boiler feedwater/steam flow control. Look for three element boiler feedwater and start downloading pdf's.
 
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