Level Gauge Slection criterion

[scada31]

In a separator vacum,for oil/water interface measurement it is suitable LG type reflex or transparent and the number of connextion minimum two or three connection required for this case.
Best regards

 

[Oldliar]

Hi!

You cannot use reflex type LG for liquid/liquid interface (also ref API 551 3.3.3.1). As the reflex type is based on reflection of the actual level, you cannot spot the actual interface bewteen oil/water (if required). So you should select the transparent type.
Regarding number of connections (several sections?) is all depending on your service.

Bonetti (

http://www.bont.it)

provides some excellent LG's.

 

[scada31]

Hi
Thank you for your response,I will choose transparent type as per your recommendation, but the number of connection it is required only tow for oil/water interface measurement in the outlet of a separtor vessel?
ragards

 

[JLSeagull]

Also consider magnetic level gauges instead of glass.

 

[Oldliar]

Hi,

For oil/water interface, magnetic level gauges will only give you the level of the combined volume, so you cannot spot the actual interface between oil/water.
For installation, various companies have various standards. TOTAL for instance has a maximum distance C-C on 2000mm. If longer range is needed, then several gauges are used, with an overlap on at least 50mm (visible). However, if the application is rather "nice", it can for sure be a longer gauge - but you might run into problems when aligning the upper/lower nozzle. Additional support might also be necessary.

 

[scada31]

Hi
Thank you for your comment,
I tray to used tow LG between the vessel nozzele,
regards

 

[Ulon]

Hi all,

I think for measuring interface, it will be better to use capacitive level transmitter or radar type

 

[JimCasey]

If you use an armored gage use a weld-pad gage that welds directly to the wall of the vessel so it becomes more of an observation window. A remote-chamber gage can have a different interface level in it than exists in the main vessel. (gage)height of lower liquid x SG + height of lighter liquid x SG=(vessel) height of lower liquid x SG + height of lighter liquid x SG. There is not a unique solution. If you extrapolate the above equation for a gas interface too, you will see that even the liquid/gas interface might be different in the gage than in the vessel.

Radar will only see the liquid/gas interface, not a liquid/liquid interface.

A very carefully weighted float that floats on the lower liquid but sinks in the lighter liquid, driving a mechanical sensor, might be the most reliable way to deal with this.

 

[Ashereng]

For water oil interface, the Agar interface probe is good.

http://www.agarcorp.com/detectors.html

We are using these on our treaters.

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