5 way manifold for DP pressure transmitter for very low temperature around -110 degc

what kind of sealing is suitable for 5 way manifold or sealing of transmitters for very low fluid around -110 degc ? is PTFE or FKM ot NBR suitable?
 
Check out pages 236-237 of Emerson's Engineer's Guide to DP Flow Measurement (2020)
You'll have to register to download the guide from the Emerson site
https://tinyurl.com/yxc4srer

Cryogenic measurement relies on allowing the cold liquid to vaporize in the impulse tubing and/or valve manifold and assume near-ambient temperature in order to avoid damaging the DP sensor with the cold cryogenic liquid.

The Rosemount guide regular and infrared photos of their close coupled DP on a valve manifold shows the transmitter body at ambient temperature. Note the ice surface temperature is warmer than the process liquid.

photo of DP xmtr close coupled to flange unions on cryogenic line.JPG

IR photo of DP xmtr close coupled to flange unions on cryogenic line.JPG

I don't think there's an issue with the valve manifold seals seeing -100°C, but why don't you ask Emerson and tell us what they say?
 
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