Level Measurement in Water Wells

[dannym6]

Greetings to everyone,

This is my case:
In a project where my team choose the instrumentation and control system we have some water wells (undergroung, as shown in picture) inside these wells there will be submersible pumps at 180 m of depth, also the well depth is close to 220m. I'd like to know which techniques or methods are the more suitable for this application. I've seen some submersible probes that measures the level from the pressure, any other option I should consider?

Thanks a lot for your time.

Danny Alarcón Saldaña
GMI Ingenieros Consultores
Lima, Perú

 

[djs]

Submergable pressure transducers is the only option I know of.

 

[danw2]

Alternative is a bubbler. The bubble pipe is run down the well.
Bubblers need clean dry gas/air supply. The bubble pipe can get heavy with long lengths.

Submersible head pressure transmitters have an atmospheric reference tube, to supply atmospheric reference pressure to the sensor. The reference tube can collect condensed water when the temperature of the reference tube is below the dew point of the moisture in the air in the tube. The condensed moisture collects in the bottom of the reference tube and creates an offset zero, so that the indicated head pressure (water depth) is less than it really is.

The work-around I've seen is to stick the reference tube (up on the surface) into a box of dessicant.

 

[roydm]

Submersible pressure transducer "Druck" is a brand I have used, hang it to a depth just above the pump. They sell a termination box c/w desicant or I have run the tube into a plastic bag.
Roy

 

[dannym6]

Thanks a lot for all your answers, I've decided to use the submersible. In relation to 'refeeence tube' you've mention the instrument's reading problems caused by condensation, would it be enough to use some desicant.

Thanks a lot for your time.

Danny Alarcón Saldaña
GMI Ingenieros Consultores
Lima, Perú

 

[MEM1]

I use globalwater submersible pressure sensors (wl450) and sensotec (LLV) sensors. Both have venting tubes. I took a short length of 3/4" pvc, put a cap on one end and a screw cap on the other end. Drill a small hole in both caps. One will be used to insert the vent tube from the pressure sensor, the other is to prevent back pressure in the tube. Put your desicant in the tube and screw on the end cap. Check the desicant periodically and change it when it starts to get a dark color.