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TDRI
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Join Date: Apr 2008
Posts: 10

Electronic sensor

04/04/2008 8:41 PM

I'm looking for a sensor that will sense the amount of glycol based antifreeze in a hydronic application. 4 to 20 or 0 to 10 mA signal would be great. Anyone know of a manufacturing company that has something like this? The application is simple really...as the level of the glycol changes, so does the signal. Any Ideas?
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Ace Boeringa
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Location: Washington USA
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#1

Re: Electronic sensor

04/05/2008 1:08 AM

Honeywell has something like that.

Are you actually wanting to measure an amount (mass or volume), a level, or a concentration.

You may know all about your application, but we know only what you have told us here about it.

After you have communicated what you are attempting to measure there will be more questions about the application.
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TDRI
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#2
In reply to #1

Re: Electronic sensor

04/05/2008 10:55 AM

The glycol based antifreeze will be circulating through a closed loop hydronic system.

What I'm looking for is a sensor that will read the concentration of the glycol giving it's analysis response in a 0 to 10mA, 4 to 20mA or maybe even 0 to 135 ohms.

As the glycol decreases, the amount of water flowing through the system will increase. Should this be a simple resistant based type sensor?
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Ace Boeringa
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#3
In reply to #2

Re: Electronic sensor

04/05/2008 11:26 AM

I would not recommend trying to determine the concentration of glycol in water by using a conductivity measurement.

A more reliable relationshp to the concentration would be specific gravity (density). There are several ways to measure SG A simple cost effective method is to measure the pressure at the bottom of a column of circulating solution that is maintained at a constant height.

I have had good luck with this system and it is pretty simple to do it yourself with a pressure transmitter and some pipe and fittings.

I can provide a sketch if you need it.
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TDRI
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#4
In reply to #3

Re: Electronic sensor

04/05/2008 11:56 AM

Thank you very much. If its not to much trouble, a sketch would be great! Thanks again.
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Ace Boeringa
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#5

Re: Electronic sensor

04/05/2008 6:22 PM

TDRI, for the sample I would recommend you tap in to your pump discharge and put a variable area flow indicator (rotometer) with a needle valve in the line, 1/4" tubing should work fine as the flow rate should be low (less than 1 GPM). This is important because if the flow is more the level will be slightly higher, so it needs to be repeatable. For your app 2" pipe for the vertical would work great, the taller it is the better resolution you will get, I would recommend 100" if possible. The liquid will overflow the 2" pipe in to the catch sink where it can drain back to your process.

To determine the glycol concentration you will need to measure the SG and compensate for temperature because SG of a solution decreases as temperature increases due to thermal expansion. Here is a link to a site that has a temp compensation table.

http://www.engineeringtoolbox.com/ethylene-glycol-d_146.html
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Skeeter
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#6
In reply to #5

Re: Electronic sensor

04/05/2008 11:36 PM

Greetings, Ace,

Would you mind revealing how you posted your drawing. I have a Mac, and am having a difficult time finding an easy way to upload drawings and photos. Thanks.

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Ace Boeringa
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#7
In reply to #6

Re: Electronic sensor

04/06/2008 1:51 AM

I don't know jack about Mac. I am a pc guy, not that I am in love with windows or anything. I use a lot of apps that will only run on windows.

Anyway if you do a normal post when the editor comes up click on the little green camera the rest is pretty intuitive. You can insert .bmp, .gif, .png or .jpg files, probably some others also. You figured out how to post text, I am sure you can figure out how to insert an image. Good luck.
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Skeeter
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#8
In reply to #7

Re: Electronic sensor

04/06/2008 3:55 AM

>>>>Anyway if you do a normal post when the editor comes up click on the little green camera the rest is pretty intuitive.<<<<

Thanks for responding... that's the problem... I've never seen a little green camera on this site, so the Mac probably doesn't recognize the PC format.

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bubbapebi
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Join Date: Apr 2007
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#9
In reply to #8

Re: Electronic sensor

04/06/2008 4:16 AM

The window looks like this in OS X 10.4.11 on Firefox. The appearance of the window is a function of the browser, not of the platform.
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Skeeter
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#10
In reply to #9

Re: Electronic sensor

04/06/2008 4:34 AM

Aha... that helps a lot. I'll pursue that angle to see if I can update. Thanks!

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Anonymous Poster
#13
In reply to #5

Re: Electronic sensor

04/06/2008 6:42 PM

Thank you very much!

Regards!

TDRI
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Anonymous Poster
#11

Re: Electronic sensor

04/06/2008 6:03 AM

Google DENSITROL.

They have what you need.
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Ace Boeringa
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Location: Washington USA
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#12
In reply to #11

Re: Electronic sensor

04/06/2008 12:04 PM

Guest,

You are correct. Densitrol is designed specifically for this purpose. I have years of experience with these instruments. I believe them to be more costly and less reliable than my recommendation.
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Anonymous Poster
#14

Re: Electronic sensor

04/07/2008 5:02 PM

Dear,

You can use simply an ultrasonic sensor for this application, u can use siemens ultrasonics sensor (siemens sonar bero), ultrasonic sensor made by Baumer Electric, also u can use Pepperl-Fuchs made ultrasonic sensor.

sobran
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Ace Boeringa (5); Anonymous Poster (3); bubbapebi (1); Skeeter (3); TDRI (2)

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