×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

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

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

(OP)
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...

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

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.

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

(OP)
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.

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

'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

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

(OP)
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.

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

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.

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!