How do I protect a transducer from transient voltages on a pipe line?
Use a non-conductive isolation bushing between the fitting on the transducer and threading on the pipeline. Be mindful of the maximum working pressure and temperature. No isolation is available if the media is the source of the transient.
Helpful links:
https://www.banjovalves.com/poly-reducing-bushing.aspx
https://www.usplastic.com/catalog/item.aspx?itemid=34914&clickid=search