[Josh Updyke] woke up one morning and found himself in a sticky situation. The demand for his modular robotic track system was outgrowing his ability to produce. One of the bottlenecks was weighing out resin. It’s a slow, monotonous process that must be done with accuracy. The free market did not have any affordable solutions to the problem. So like any hacker worth his weight in 2N2222 transistors, he made his own by re-purposing some used beer kegs.
The resin comes in two parts – the resin itself and a hardener. Each must be weighted out on a scale before mixing to ensure proper proportions. It was a trial-by-error learning process before [Josh] was able to settle on a final solution. First he tried some garden sprayers, which worked OK at first. But the resin was taking too long to exit the sprayers, and he had to pressurize them by manually pumping them with air. He ended up with a much better method that used some Cornelius Kegs.
Be sure to check out his io page for more details.
That doesn’t look like a beer keg, it looks like one of those tanks some people use to spray poison on their plants
lol, it def is, Roundup branded and all…
That photo is of his old dispenser, which is as you say, sprayer bottles.
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Nice job (and a nice problem to have!). However, this post would have been better if they’d shown the pic that had the beer kegs instead of the Roundup cans. I’m sure that’s going to make some question what you’re drinking around your house :)
More bitter, more manly, beer is for wimps :)
A word of warning with resins, wear PPE when handling this stuff. You can suddenly become sensitive/allergic to it without warning, it happened to a friend. After talking to a supplier of resins this is not uncommon so just be careful if you want to keep using it in the long run.
Yep. PPE and environmental/engineering controls (ie, ventilation and limiting time in contact or proximity with chemicals) will help to prevent sensitization.
Out of curiosity, why not use a tank with a tube exiting at the bottom and let gravity do it’s job?
think dispensing honey
If he used good resin metering pumps are available. They work very well. ;-)
My first thought was to build something out of PVC pipes. I believe 4 inch pipe will hold >100PSI continuously (cyclic stresses may weaken).Use a section long enough to hold what you use in a day or week. Cheap and easy to replace/upgrade. Also withstands vacuum. Make the tube and bottom cap as one piece. Make the top cap connections for air/vac, and a dip tube to the bottom for dispensing. Share air/vac with all containers.
Theres nothing people in the hackaday comments section love more than a pvc pressure vessel.
I tried doing that but it made the beer taste funny.
I would think something like a peristaltic pump would give better control, and could be automated.
Since I have a few of these kegs in use for their intended purpose…I can tell you the parts to maintain/repair are a lot cheaper than if something goes south on specialized equipment. These things go through seals both on the couplers and the lid (~$10/set) Testing your repair in depth requires just over 4 gallons of beer, some CO2, a fridge, a tap, an iced mug and some friends :-)
On a practical note: these things do not tolerate >60 psi of gas very well. The inherent design where the o-ring sits on the top is not intended for that kind of pressure and blows easily (developed to dispense soda syrup, methinks). It’s two flat surfaces mating on that o-ring held in place with spring pressure.
It is a good idea. Used corny kegs are cheap and spare parts are easy to find.
Just make sure these kegs won’t be used for beer or soda again.
Thank you all for the comments. It is always cool to see some of my work published on HAD. All of your comments are great and I thought I would just reply to a few of them.
1. I am not sure why they choose that picture over the other one on the page that actually shows the kegs. Oh Well, it is out of my hands.
2. The comments about PPE are great. One of the reasons for building this dispenser was to avoid contact with the resin as much as possible.This was for health reasons, but also because it is sticky and annoying. So having a clean and easy way to dispense it without touching was key. If you are careful you can do the whole job without touching the resin at all.
3. Why not use gravity feed, pumps or metering equipment? Well this resin is quite thick and gravity is slow which reduces my production rate. Pumps could work, but honestly I didn’t really want to use one. The industrial method is to use a pressure vessel and it made sense to copy that as much as I could. These kegs are basically the same thing as the industrial $1200 model.
4. Thanks for the comment about not going over 60psi. Right now I am running them around 35 psi and the resin flows quite fast (almost too fast if you are not paying attention).
Again, that you all for the comments. I can’t wait to show pictures and video of the several tank robots in the works now.
Cheers.