Do you have any standard information regarding transmitter impulse tubing tapping on process line in case of different fluid, like liquid/gas/steam, etc.

 

It really depends on a lot of different factors. I assume you are referring to a horizontal line.
In 90% of installations:
For liquid usually at 3 or 9 o'clock position
For gas usually the top (12 o'clock)
For steam it depends on what instrument is connected and where it is located.

A pressure gauge is usually at the top with a siphon unless the gauge is below the line, in which case you would use a 3 or 9 o'clock connection so that the impulse line fills with condensate.

An orifice plate has 3 or 9 as well with condensate pots to give a constant condensate level.

As a rule, never connect to the bottom otherwise any scale or entrained liquid will enter the tubing. Connecting to the top of a liquid line will allow entrained gas to enter the impulse tubing, not always a bad thing. Freeze protection is something to keep in mind. If you have a specific installation, post it here and you will get several different options.

Regards,
Roy


On September 13, 2008, bhushan_mpc wrote:
> Do you have any standard information regarding transmitter impulse tubing tapping on process line in case of different fluid, like liquid/gas/steam, etc. <

 

I can refer you to the standard BS 6739:1986.
The standard shows an arangement for tappings on the process pipework for the impulse tubing shown on page 87, figure 4.