Lost my liquid compensation column in measurement liquid level by diferenctial pressure
Lost my liquid compensation column in measurement liquid level by diferenctial pressure
(OP)
Hi¡ My name is Alejandro and y work in a power plant. I have a pre-heater off low pressure whose internal pressure is vacum (near 0,3 bara). I have tree instruments of diferential presure for measure the level. I put water in the reference column (superior tap), but part off this column disappear. I think that this water is evaporated, because de pressure in the heater is lower than seteam pressurre at the temperature of the column, so I have two possibles solutions:
1.- Look for some method to refrigerate water column like one pipe of refregeration water near the tubing.
2.- Use glycerin like compensation fluid and change the range off instrument. The problem is that if the glycerine also is evaporated it could mix with water in the water steam cycle and it cluld be dangerous
I would like your opinions about this solutions an others than you know work properly for this problem.
Excuse by my English.
1.- Look for some method to refrigerate water column like one pipe of refregeration water near the tubing.
2.- Use glycerin like compensation fluid and change the range off instrument. The problem is that if the glycerine also is evaporated it could mix with water in the water steam cycle and it cluld be dangerous
I would like your opinions about this solutions an others than you know work properly for this problem.
Excuse by my English.





RE: Lost my liquid compensation column in measurement liquid level by diferenctial pressure
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RE: Lost my liquid compensation column in measurement liquid level by diferenctial pressure
Thank you very much.
RE: Lost my liquid compensation column in measurement liquid level by diferenctial pressure
RE: Lost my liquid compensation column in measurement liquid level by diferenctial pressure
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Lost my liquid compensation column in measurement liquid level by diferenctial pressure
A couple of ideas
Add a constant makup of water
Try running the leg dry.
I have had goos sucess by running the dry leg up to a point several feet above the top tapping point then down to connect. This way any water that does condense in the line runs back to the vessel.
You could also add a drip leg to catch any that does happen to accumulate.
RE: Lost my liquid compensation column in measurement liquid level by diferenctial pressure
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RE: Lost my liquid compensation column in measurement liquid level by diferenctial pressure
To put air purge is imposibble in this case.
Thank you very much.
RE: Lost my liquid compensation column in measurement liquid level by diferenctial pressure
There may be sone condensation in the dry leg but not much, I think the air remains in there.
Any condensation should run down into the drip leg below the transmitter.
I think the problem with your existing setup is the wet leg is above the vaporization temperature at vacuum, you could also try something like an un-insulated condensate pot, perhaps even cool it down with water so it's below the boiling point.
Can you top up the wet leg with a steady water purge?
I'm sure you will come up with a solution, we will be interested to find out what it is.
Roy
RE: Lost my liquid compensation column in measurement liquid level by diferenctial pressure