On the transmitter: exhaust/vent
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What is the purpose of the vent/drain plug on the transmitter? Is it the gas in the medium during the measurement process, or rather the liquid that constitutes the medium? If that’s the case, can we then disregard the vent/bleed valve during the transmitter installation?
Venting/venting liquid is generally done on the transmitter’s gauge; there is no need to install additional venting/venting valves on the transmitter! Besides, exhausting and draining only at the header is useful
Reply to 2# *aobodao: It seems that it can be used in this way, but according to the installation guidelines, an exhaust valve needs to be installed; it seems impossible to use it without it.
Those included with the transmitter do not count; please refer to the installation manual for details.
Although both can discharge gas/liquid, they are two different concepts. The former is used for drainage on the transmitter body, while the latter is used for drainage in the pressure guiding pipeline ； The former is small, the latter is large ； The former is generally a small NPT plug, while the latter is generally a ball valve/needle valve ； The former generally emits more dangerously and is difficult to collect, while the latter is the opposite ； In short, all of them are necessary.
The drain hole on the transmitter is intended solely for checking the transmitter and draining fluid from the diaphragm box; it cannot be used for purging or draining pipes
Reply to 3# jcgssjy: I might not have understood what you meant before. For split-type units, a separate drain valve is definitely necessary; whereas for integrated units, such as integrated orifice plate transmitters, no separate drain valve is required
Transformers generally do not require a transmitter drain valve, but those with flow measurement and pressure guiding tubes need such a valve