How to span a differential pressure transmitter on a horizontal exchanger

[slogsdon]

All,

In order to understand the liquid level in a thermosyphon horizontal heat exchanger a differential pressure transmitter will be located on the head (top & bottom) of the exchanger to monitor liquid level. In this case, the steam is on the shell side and the process fluid is on the tubes. The exchanger has a 70" O.D. The process fluid has approximately the same density as water. When spanning the DP, I'm assuming I would use 0 inH2O as my 0% and as my 100% would that be 70 inH20? Are there other factors that need to be considered such as the pressure above the reboiler (i.e. from process lines or from the liquid level in the column.)

I appreciate any input you have, this is my first time working with DP cells.

Thanks!

 

[danw2]

I'm confused.

If the process fluid is on (in?) the tubes and the steam is on (in?) the shell, what level is being measured? Condensate in the shell?

Or is the steam passing flowing through the tubes heating the process fluid in the shell and you need the level of the process fluid?

 

[slogsdon]

The steam is passing through the tubes and heating the process fluid that is in the shell and I need the level of the steam/condensate in the head of the exchanger. The DP cells are being put on the head of the exchanger which is where the condensate will collect.

Hope this helps clarify. Thanks