water glycol mix

can anyone tell me a good and cost effective way to measure the water/glycol mix in a chiller system. my customer wants to know the % of glycol in the mix. ideally i would like to have some type of a device that would give me a 4-20ma output. thanks for any and all input.

You need to measure the specific gravity. If the sensor can be placed where the liquid level is static, a float actuated sensor should do the trick. If the level is dynamic, then you might need to use a bowl and circulate the liquid through the bowl. The level in the bowl will remain the same, but the float position will change according to the specific gravity. You might have to play around with weighting the float to get the desired results.

http://www.omega.com/ppt/pptsc.asp?ref=LVR50&Nav=grek02

do you know of a mfg. for the sensor.

Click on the link in my previous post.

Here's a hydrometer that looks like it floats on the surface. Might be better if the level is dynamic: http://www.gardco.com/navigation.html

Just click on the links and study the info.

A common method to measure concentration is conductivity. Basically same system as that used for pH. Whether there is a sensor for glycol (which one by the way??) and water I don't know. There may be a ready made one or you may have to take an unit and calibrate it with varying concentrations.

Places to check
VW Rogers
Ryan Herco
Harrington
Why do they need this much measurement? Seems to me weekly or at most daily with a "hand held" hydrometer should suffice -- mostly asking this for my curiosity and learn something new.

Dan Bentler

glycol

they have 3 cooling systems and they are automaticly filled with water as needed.the ratio then gets out of wack and when it gets too far he would like to know.

do you know of a sensor that has worked in this type of a system.(mfg. & type)

You need to measure the specific gravity

Click to expand...

I don't know if this will work with glycol. I had this same problem one time before and the chemical engineer in our plant said glycol could not be tested this way. Im not sure if this is correct but I do know we did not have a good way of testing.

We had a make up water tank that we used to fill the towers. First we installed a simple float to fill the make up water tank. Then we installed a % mixer inline with the supply water. This way as the tank filled we always got the correct mixture. We were also able to increase the % as the temp got colder.

they have 3 cooling systems and they are automaticly filled with water as needed.the ratio then gets out of wack and when it gets too far he would like to know.

do you know of a sensor that has worked in this type of a system.(mfg. & type)

No I do not I would have to chase it down - use the sources I mentioned or the web pages ie Google.

Generally if it is only water evaporating the glycol will not evaporate (as much) therefore the concentration will be about same after adding water. EXCEPT for leaks - seems to me they need to fix these.

I'm sorry but I think there are limits to automation. This is one in my mind. I still favor the hand held hydrometer and manual addition. Maybe when they get tired of lugging cans of glycol they will fix leaks.

Dan Bentler

A manufacturer of antifreeze controls the blend of water and ethylene glycol with a combination of
- density from a coriolis flow meter and
- a specialty, in-line concentration meter that measures and reads out in percent concentration of solubles in water (manufactured by K-patents, a Finnish firm.)

Either is a precision on-line instrument, neither is a cheapie grab sample checker.

There are lab style, desktop densitometers that will check the apecific gravity or density avaiable from lab supply houses.

CharlesM said:

I don't know if this will work with glycol. I had this same problem one time before and the chemical engineer in our plant said glycol could not be tested this way. Im not sure if this is correct but I do know we did not have a good way of testing.

Click to expand...

How do you check the antifreeze in your car?? With a hydrometer...Balls that float in a tube.

We were using "Bio" glycol so it could go down the drain if needed. In the old day's we could check it just like your car but not the new stuff.

Just make sure this will work before spending a bunch of money on a sensor.

Almost any two part mix of water and water soluble can be measured with a hydrometer. The reason is they have two different densities. The overall denistiy will change with concentration. Battery acid and ethyylene glycol mix are the two most well known. Others include concentrations in metal plating tanks.

Now then if the other material is more conductive than water you can use conductivity. Examples are acids bases (pH) salts, etc etc. These are done with cells cal'd for specific material. So if you have a X cell and a Y cell you should be able to get concentration of X and Y - in theory - been a few years since my quantitative chemistry lab course.

After that you get into more exotic methods Atomic Absorption (gneraly based on metals) chromatography, etc etc.

Do NOT think I am saying it cannot be done. I am saying I have just never seen or used any system to check antifreeze concentration other than hydrometer. I would be curious and interested to learn it can be done.

Dan Bentler

If you want to see if it will work, get three bowls. fill one with pure water, fill the 2nd with 50-50 water glycol, fill the thrid bowl with 100% glycol. Now get a ping-pong ball and tape a couple of washer to it. Place the ball in each bowl noting how the ball floats, Hi, low, and somewere inbetween. The ball will float at a diffent level in each bowl. That's basicly the idea. The trick is to circulate the coolant and keep it level in the test bowl.

elevmike said:

If you want to see if it will work, get three bowls. fill one with pure water, fill the 2nd with 50-50 water glycol, fill the thrid bowl with 100% glycol. Now get a ping-pong ball and tape a couple of washer to it. Place the ball in each bowl noting how the ball floats, Hi, low, and somewere inbetween. The ball will float at a diffent level in each bowl. That's basicly the idea. The trick is to circulate the coolant and keep it level in the test bowl.

Click to expand...

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.

However Mike you still need to finish the PLC controlled panel cut machine. Don't be goin off on these tangents. YOu need to learn discipline and stay on one project till completed. When you succeed come and teach me how to practice what I preach.

Dan Bentler

Dan, I'm STILL workin' on that damn go-cart! Between the go-cart, plazma table, some gizmo to measure wire & cable, the stupid alarm system, upgrading the network & accounting system, it's a wonder we're in the elevator busniess. I Thank God for a good staff.