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Liquid Level Indicating

Liquid Level Indicating

Liquid Level Indicating

(OP)
Im looking for a liquid level indicator for a new test bench run by a Micrologix. I cant seem to find something that is capable of measuring a 15 oz difference in fluid level.

The problem Im finding is that they can cost upward of a grand - not feasible for what we're trying to accomplish.

RE: Liquid Level Indicating

There are lots of cheap options out there,
Do you need continuious level"
Fluid?
Level range in " or mm
Do you have an air supply available?

RE: Liquid Level Indicating

(OP)
inch level - I dont really need continuous level but would like it if possible.

Ive got all the air you need - or I need in this case.

RE: Liquid Level Indicating

As you have air you can use an inexpensive pressure transducer with a bubble tube to measure the level. Cells are available for < $30.
Another option capacitance
A crude float type using a potentiometer.
It might be less hassle to just buy a low range DP transmitter on e-bay.
Check out the Omega catalog for level.
Roy

RE: Liquid Level Indicating

15oz diference, is around 30ml, I would doubt that a bubbler tube would have the required resolution to indicate that change. More infomation is required, what is the vessel shape and dimension, what fluid is being handled.

Mark Hutton


 

RE: Liquid Level Indicating

Here is a link to a few transducers from Honeywell. It looks as though the 22PCAFA6G with a span of 1# would work for you. It has an output of 42mV full scale so you could put it directly into a mV input or make a circuit with an op amp to boost it up.
http://www.e-sonic.com/aboutus/cat/P/pressure%20transducers.pdf
Don't try measuring your fluid pressure directly, that's why I suggest a bubble tube.
HEC, We use bubble tubes all the time for measuring very low differential on interface and density applications, mainly because our applications are very nasty and other types will not stand up.
Regards
Roy

RE: Liquid Level Indicating

(OP)
Yeah, I checked Omega for level indicating. MOst dont seem to have a small enough res and the floater is 700 bucks.

The media is Turbine Oil - Texaco R&O 68.

RE: Liquid Level Indicating

I assume "turbine Oil" is non conductive, and not too viscous, perhaps you could just connect the cell I pointed to at the bottom of your tank to measure the static head directly. You would need a 10 VDC excitation source and a mV input card (or mV/mA converter) for the PLC.
I assume your tank is about 24" high.
Even if you dont use the whole range of the cell it should give you enough resolution.
Sketch Attached
Roy

RE: Liquid Level Indicating

(OP)
Hey THANKS!!

I can build the tank to whatever spec necessary to accomodate the sensor. This should work out just fine!

RE: Liquid Level Indicating

Yes, another good Canadian company "Milltronics" gobbled up by Siemens, not inexpensive though.
Roy

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