Humidity meters

[Head Womble]

I've been thinking about the process of drying oil and bio,
now if we had a fan blowing into a sealed tank (with spray bar) with an outlet pipe,
and measured the humidity of the air blowing and the air coming out we would know when the oil/bio was dry.

The same setup could be used for testing if bio was fully demethed, you'd just need to use a different meter.

What are your thoughts on this ?

[Head Womble]

Something like this could be used.

http://www.ebay.co.uk/itm/Digital-Humidity-Meter-and-Thermometer-Sensor-for-Incubator-Egg-Car-inside-/190823398088?pt=UK_Pet_Supplies_Poultry&hash=item2c6df5fac8

[CHUNDER]

I  Have more important things to think about   

[Julian]

You're only measuring the humidity of the air.  For that to be effective you need to guarantee that your drying process is continually removing moisture from the bio/oil.

For what those meters cost it's got to be worth a try.  Far better but more difficult to monitor the moisture content of the bio/oil.

You can get bathroom fans which are controlled by humidistats.

[Tony]

An interesting idea.

The humidity of the exhaust air (and the air over the liquid) is likely to vary greatly depending on the speed of the air.  IE for oil that is equally damp, fast air flow will result in less humidity than slow air flow where the air has longer to pick up moisture.

For drying you really want a decent air flow, however this may not show much humidity - I think for it to work you'd have to use a fairly slow air flow to allow the air to pick up enough moisture to show on the meter.

[julianf]

Im sure it must have been mentioned before, but what about testing the electrical conductivity of the fluid?

If that were possible, then a couple of probes at a fixed distance would give a quantitative result without having to account for as many variables.


...but, yes, i also think the use of a humidity meter is a good idea.  It would only give an indication on a fixed setup though, so would never be comparable to other people's setups, unlike if the fixed probe idea had any substance.

[nathanrobo]

I'd look at Keith's home made Sandy Brae tester to measure ppm's.  This would be more accurate than looking at the air above it, although you could correlate sandy brae testing with the humidity levels, although RH levels change so greatly, I'd imagine that it'd give unreliable readings.

[Julian]

Im sure it must have been mentioned before, but what about testing the electrical conductivity of the fluid?

If that were possible, then a couple of probes at a fixed distance would give a quantitative result without having to account for as many variables.


...but, yes, i also think the use of a humidity meter is a good idea.  It would only give an indication on a fixed setup though, so would never be comparable to other people's setups, unlike if the fixed probe idea had any substance.

GL has a conductivity sensor on his site ...

http://www.graham-laming.com/bd/dipstick.pdf

[Head Womble]

GL has a conductivity sensor on his site ...

http://www.graham-laming.com/bd/dipstick.pdf

I hadn't seen this, but it is the answer to something else I've been pondering over.

[Julian]

GL has a conductivity sensor on his site ...

http://www.graham-laming.com/bd/dipstick.pdf

I hadn't seen this, but it is the answer to something else I've been pondering over.

No, a cattle prod is something completely different.

[Head Womble]

GL has a conductivity sensor on his site ...

http://www.graham-laming.com/bd/dipstick.pdf

I hadn't seen this, but it is the answer to something else I've been pondering over.

No, a cattle prod is something completely different.

Tazer on a stick, I have one allready.

[nathanrobo]

Actually, notwithstanding what was mentioned before, a guy on the LC forum, who specialises in automating things mentioned using a sensor in the drying tank, which would work with a logic board and switch off the pump when the fuel is dry.

The only difference vs. the suggested method here is that the sensor would reside somewhere in the tank rather than in the atmosphere immediately outside of the tank.