keg ultrasonic liquid level sensor. - Page 2 - Home Brew Forums

 Home Brew Forums > keg ultrasonic liquid level sensor.

11-29-2012, 07:43 PM   #11
techbrewie
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Nov 2012
Fargo, ND
Posts: 340
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The reed switch will be there for other "on pull" functionality. So I just figure that I might as well.
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11-29-2012, 10:40 PM   #12
TJTHEBEST
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Dec 2009
Arcata, Ca
Posts: 149
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I sealed a pinhole leak in a keg with jb-weld. I tested it up to 35 psi. it worked great.

11-29-2012, 11:17 PM   #13
aphid_rancher
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Feb 2010
Spokane Valley, WA
Posts: 50
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I fixed the radiator in my car after taking a rock hit about 15 years ago. It was a small hole but it made me a believer. I presume the hole you are making is just big enough for two or three wires to pass through.
I tried to use an IR thermometer to measure water and it more or less saw right through the water to the bottom of the pot (where it was hot from the stove). Will this be a problem with an IR distance sensor and beer of some color?

11-30-2012, 06:11 PM   #14
audger
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Apr 2011
., Connecticut
Posts: 1,497
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ultrasonic distance finders have been discussed before. ive never seen one made to work.

probably a more accurate (and sanitary) way to do it would be to put a mass flow sensor in the gas line, and a gas pressure sensor. with those two measurements (plus temperature), you can calculate the volume of headspace in the keg, and by extension, how much liquid is left.

if you know you put in x-amount (mass) of CO2, and X-amount of gas raised the pressure by Y-number of PSI, you can determine volume of space filled by the gas by the formula pv=RT (ideal gas law).

11-30-2012, 09:01 PM   #15
Gritsak
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Aug 2009
Posts: 605
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Couldn't you simply base the calculation off the weight of the keg. In other words, weight the keg with no beer in it, weight it full, subtract these values and convert that weight into gallons of beer. You'd have to leave the keg on a scale, or perhaps check it at intervals, but at least you wouldn't have something floating in the keg with a jb welded lid.

11-30-2012, 10:27 PM   #16
jeffdietzler
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Jun 2010
Riverside, California
Posts: 15
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For you experiment, why not just use a fermenting lid with the stopper/sensor inserted from the inside? Maybe it could hold serving pressure that way?

http://www.homebrewing.org/Corneliou...ter_p_999.html

12-01-2012, 06:41 PM   #17
beaksnbeer

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May 2011
New Port Richey, Florida
Posts: 2,845
Liked 507 Times on 335 Posts

Often wondered if a float fit around the tube out reading distance. Use them to read how much we have inside of 55 gallon drums at work. Brighter minds please chime in.
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03-07-2013, 09:23 PM   #18
fc36
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May 2010
Chicago, Illinois
Posts: 367
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Quote:
 Originally Posted by aphid_rancher JB weld will seal the hole up well enough to hold pressure. You will want to pot your circuit to make it submersible and may want to worry about doing it in a food safe way. There are food safe adhesives and sealants available. Interesting idea.
Quote:
 Originally Posted by Gritsak Couldn't you simply base the calculation off the weight of the keg. In other words, weight the keg with no beer in it, weight it full, subtract these values and convert that weight into gallons of beer. You'd have to leave the keg on a scale, or perhaps check it at intervals, but at least you wouldn't have something floating in the keg with a jb welded lid.
JB Weld is food safe.

03-07-2013, 11:36 PM   #19
alien
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Apr 2012
Posts: 1,235
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No it ain't. Show me where it says that.

03-08-2013, 02:49 PM   #20
fc36
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May 2010
Chicago, Illinois
Posts: 367
Liked 24 Times on 19 Posts

Quote:
 Originally Posted by alien No it ain't. Show me where it says that.
Please don't immediately naysay without doing your own fact checking and/or basic search.

First off, as a chemical engineer and former hazardous waste lab pack chemist, we encountered JB Weld and other isocyanates all of the time. Unmixed and uncured they are considered a flammable solid, class 4.1. However, that is because when mixed, the resin and hardeners actually undergo an exothermic reaction and release heat in small quantities. That being said, once cured and all solvents have evaporated (15-24 hrs of set time), the now uniform solid gray putty is virtually an inert piece of plastic. Unmixed JB weld and other isocyanates were always packed separately from each other (i.e. resin in one bucket, hardener in the other), but cured and hardened JB Weld and other isocyanates were tossed into the drums with all of the other non-hazardous chemicals (i.e. talc, sodium chloride and other salts, and tons of other chemicals). As an aside, I never once got a ticket for improper packaging of materials and I also never screwed up a drum inventory or manifest.

http://www.jbweld.com/faqs/

Read the JB Weld FAQ page and see what it says. It states that "When fully cured, J-B Weld is non-toxic. However, we do not recommend consuming the product." So don't go eating any. Also, it states that "Original J-B Weld can withstand a constant temperature of 500ºF.", which is far below the temp you'll be storing beer at (35-55ºF). And to top it off, it states that "When fully cured, J-B Weld is completely resistant to water, gasoline, and about every other petroleum product or automotive chemical." So it will not just dissolve into your beer.

I now point you to a post I found right here on HBT: http://www.homebrewtalk.com/f51/will...2/#post2266853

This post has a link to an NSF certified test of several JB Weld products in contact with a potable water system. It states that "The exposed surface area of each sealant in a household distribution system shall not exceed 1.3 sq. cm/L or .2 sq. in./L." So let's do some simple math.

5 gallons = 19 Liters and 19 L * 0.2 sq. in./L = 3.8 sq. in. or 24.7 sq. cm for the non-Americans out there.

This tells me that unless you decide to coat 3.8 sq. inches of the inside surface of your corny keg with JB Weld and it's in constant contact with your beer, you'll be completely fine.

http://www.jbweld.com/wp-content/upl...-Weld-MSDS.pdf

Lastly, we turn to the actual MSDS of JB Weld. If you look at the ingredients list many of them are food safe in and of themselves. The ones in question are all either solvents (they evaporate completely upon full cure) or active ingredients (they are rendered inert by the curing reaction). So there you have it. JB Weld is fine to use for sealing a small 1/4" hole with a level sensor at the top of the keg that is unexposed to beer. Of course, you can always choose to use something else, but that's all your own preference.

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