water glycol mix

[TConnolly]

Is the customer using glycol because he is operating the chiller at less than 45F (8C)?

Or is the glycol to combat corrosion?

If it is for corriosion purposes there are much better ways to do this. Glycol significanly lowers the specific heat of the coolant, so while it also lowers the freezing point, it makes the chiller much less efficient. Corrosion inhibitors such as Boron Nitride solutions however do not radically alter the specific heat of the coolant solution, and concentrations can be monitored with a inexpensive PH meter.

 

[GaryP]

A refractrometer would be the ideal piece of equipment to measure the specific gravity of the mix. However they are usually hand held and visual output instruments. I am checking to see if anyone makes a "electronic" version and will post the information if I find one.

Here is some refractrometers. I do not know if any have a output other than display. But a good websearch might find something.

http://www.coleparmer.com/catalog/product_list.asp?cls=15007&par=0,5116&cat=1&sch=318&sku=&sel=&pfx=

 

[rsdoran]

Why didn't y'all say you wanted a refractometer with 4-20ma output...gee whiz
http://www.refractometer.com/products.html

 

[leitmotif]

Ahhh yes the go cart. See what I mean about finish one project before starting another?? I even forgot the go cart. Like I said when you learn how to do that discipline thing come and teach me to practice what I preach.

Dan Bentler

 

[leitmotif]

I just thought of something. From quant chem lab class. Concentration is also measured by transmission (absorption) of light. Now a glycol solution may absorb too much light but,,,,,,,, worth a try ????

Dan Bentler

 

[Doug_P]

Hmmm now all you gotta do is hook you ping pong ball to a circuit whose output is proportional to "submergence ??) of ball and voila and electronic hydrometer. Calibrate submergence to concentration and you have it.

How about a distance measuring device - ultrasonic or laser - which shoots down from the top of the bowl to the ping pong ball? The 'submergence' of the ball varies the distance to the sensor, the output of which is run through an algorithm to arrive at specific gravity/glycol percentage. A second measuring element could be added to look at just the liquid level, giving the ability to compensate for level variations.

.02

 

[elevmike]

Doug,

To measure specific gravity with a float sensor you need a short rod with high resolution. Your idea to compensate for level with another sensor would require a longer sensor, thus a loss in resolution. Possably the best thing to use would be the refractometer that Ron suggested in post 18.