Hi all,

LP separator level indicators design and operation are varied and at times problematic. Some accumulate oil, some indicate a wrong level, and some show a fluctuating level that can't be a true reflection of the liquid level in the LP separator.

The attached photo is of one such separator sitting above a thermosyphon PHE supplying 2.5degC chilled water on a FRICK package with stable pressure control. The difference between the ammonia level being below the bottom sight glass and above the 3rd sight glass is about 60kg of ammonia which can't be true.

I'm not a fan of this level indicator leg design and connection into the main liquid leg, the drawing shows it is having a fall, yet it is level. I envisage velocity pressure and gravity fall having a bearing on what is seen in the level glasses. With a high side float valve on the outlet of the condenser PHE the entire charge would easily fit into this vessel therefore is a high-level switch really needed.

What do you folks think?


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