why the pressure gauge line from the pipeline to the pressure gauge will be circular in middle

 

Hi there,

I am nor sure what you mean by "circular" so I have to assume you are referring to a "pig tail" in the line. We normally make the "pig tail" in a tubing line to absorb some of the vibration effects on the line of the surrounding area.

Vibration could cause metal fatigue in the tubing and cause it to break in time or could cause a blowout which could cause a fire or initiate a shut down due to low pressure, so it is a simple but effective and important part of a installation in high vibration areas for transmitters as well as local indicators.

Normally it is not needed for low and medium vibrations areas only in very high vibration areas like on a diesel generator or on a PD compressor.

 

Perhaps you are referring to a gauge on steam service a curly loop like pigtail, usually called a syphon.

It's to trap condensed steam, it fills the gauge up with water to prevent live steam heating the gauge and destroying it.

Roy

 

dear roy

thank u for giving me the reason for providing pig tail in pressure gauge port. but according to your statement it has to be kept for hot liquid passing tubes only. but i found this pig tail is also found on the cold tubes i.e on chiller discharge water tubes.