Pigtail siphons are installed on steam line in order to protect the pressure gauge and related connections from the medium.
The curved part of the siphon generates a condensation formation that remains in the curved part of the siphon to protect the measuring instrument.
It is imperative to use a pigtail siphon on all devices when the temperature of the medium is 100˚C (212˚F) or more, it allows the hot medium to cool before entering the pressure instrument.