Pressure Transmitter Protection


Thread Starter


I need to use a differential pressure transmitter for steam flow at high pressure and temperature. Can anybody suggest me which will be the most smallest DPT which can be used without need of high temp and pressure protection like condensing pots?

I am presently using ABB's DPT with condensing pots but I want to reduce size of my test rig, so please suggest me appropriate DPT which will be miniature one and can sustain high temperature (150 to 230 degree Celsius) and high pressure.
Properly installed tubing with the transmitter below the lowest connection, and back-filled with condensate through purge and drain fittings, generally works. Freeze protection as needed.

You supplier, has or should have the recommended installation setup for your reference.

High pressure steam is always dangerous, safety first.
Several years ago an Emerson rep noticed that a DP was close coupled to the manifold for an averaging pitot tube and was concerned that the conducted heat would degrade the performance and kill the transmitter. But it had already run satisfactorily for some time. Emerson investigated wrote up the case and published it.

The original note, dated 2010 is here (on a vendor site):

My page one Google search indicates that that note seems to have disappeared from the Emerson site.

Jim Cahill, Emerson's blogger at the time, wrote "Consider Top Mounting DP Flowmeters in Steam Applications"

A second note, aimed at geothermal flow apps, is current on the Emerson site:

I don't know why the first one disappeared. Could it be that long term, the close couple doesn't hold up? I don't know.

Since it's your rig, you can assess your own tolerance for the risk of not using conventional wet legs and condensate pots.

I doubt that any other major vendor has substantially different temperature or pressure specs for steam service.