Have you considered other scenarios than exposure to solar radiation that could justify a thermal relief?
Say, could situations arise where the liquid is colder than average soil temp, and the pipeline is then blocked in and temperatures line out over the large distance. Or say, a minor bush...
Thanks for the informative and very precise answers !
Prior to posting the Q here, I had used Google for "car sealed" or "carr sealed" valve - it turns out that "carseal" is a much better search term.
Shows the potency of Google - but also the superiority of asking humans.
Frank
Denmark
As I understand, a "car sealed" valve is "locked" in position - either open or closed.
Sometimes plastic strips are used, could also be more substantial locking device.
-Does anybody know the origins of this weird expression "car seal" ?
TIA
