Building an Oxikit DIY Oxygen Concentrator
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- Опубликовано: 13 июн 2024
- This time we're talking about Pressure Swing Adsorption and how we can use fancy sand to pull pure oxygen out of thin air.
Errata and Clarifications:
- If you are going to use PVC pipe to store pressurized gas of any kind at any pressure, you MUST use pressure rated pipe and not "thinwall" or "DWV" pipe. I chose Schedule 40 pipe, which is the thinnest walled pipe that has a pressure rating, but there are such things as Schedule 80 and 120 pipe. Using pressure rated pipe does not make it safe to do, it just makes it safer. (Cheers, @Spirit532)
- Some concern has been raised about material fatigue caused by pressure cycling. I'm not convinced that a 30 psi pressure swing meets the threshold to cause this kind of failure, but the concern is probably well-founded. A failure of this kind at 30 psi could be scary, but probably not lethal. The chances are good that a failure would be unexciting, if it ever occurred. PVC is not a brittle material and is also very resistant to oxidative reactions. I will be sheathing my cannisters in something to prevent shrapnel just in case. (Cheers, @NicolasBana)
- Sieve is pronounced /sɪv/ and I know that in any other context (I pronounce it correctly in the idiom "leaks like a sieve") but I learned to pronounce "molecular sieve" from @NurdRage, for better or worse, and his incorrect pronunciation has stuck with me. (Cheers, @nilo70)
- My description of the PSA cycle is not entirely accurate. I state that the equalizing valve is mostly responsible for purging the nitrogen from one tank to another, but that's not exactly true. Most of the purge actually happens via the orifices in the output junction. The equalizing valve theoretically "primes" the unpressurized canister with the last bits of pressurized O2 from its counterpart (because the tank will adsorb nitrogen better under pressure, so if you already have some O2 pressure in there when you start pumping in air, you'll pass less nitrogen as the pressure ramps up) I may address this in a follow-up video, but this is still not a bad introduction to the PSA cycle.
- Some of the PSA cycle diagrams show out of order, mostly when I cycle through them quickly. What I'm describing is still correct and any diagram that is discussed for any length of time is correct, it's just some of the quick ones. This section is a Google Slides stack that I recorded with a screen recorder and at times I advanced the slides in the wrong direction without noticing.
- If it is working properly, the oil in an oil-filled pressure gauge will never contact the process gas. What I describe as a hazard is absolutely still true, however. Please do not use oil-filled gauges in oxygen service. In fact, if I were building this machine for someone else to operate, I would take apart the cheap pneumatic valves, wash them in degreaser, and re-oil them with a fluorinated oil for reactive gas service. Take care to look into the oxygen compatibility of anything that has to carry pressurized O2 (Cheers, @AdvancedTinkering)
- When describing the tool used to agitate the sieves in the OxiKit video, I call it a "pneumatic vibrator." In my head, they used a concrete vibrator. Watching the footage back, they're clearly using an air hammer. If you go looking for that tool, it's called an air hammer. I don't necessarily recommend using it for this, however. They make a point to run it at low pressure and to only contact the fittings with it and not the pipe wall directly, but it still seems easy to damage your PVC this way. Buy a muscle massager instead, you deserve it.
- I describe the gas separation mechanism as "having to do with the relative size of the molecules" which is sometimes the case with molecular sieves but in this case, the mechanism is actually electrostatic and ion exchange interactions! This is why the metal cation (Li vs Na) bound to the zeolite affects the selectivity. (Cheers, @justliberty4072)
Check out the Oxikit project here:
oxikit.com/
You can stay up to date and support me on Patreon here:
/ integratedtherm
And if you want more info on my build, you can read the blogposts here:
www.nickpoole.me/
And check out the Github Repository:
github.com/NPoole/PSA_Oxygen_... 
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Excellent build! We definitely need more oxygen concentrators instead of cylinders.
There's one REALLY important thing to mention - you *must* use pressure-rated PVC pipe if you're going down that route. NOT drain or other unrated pipe! The difference between the two is a very violent explosion that sends large shards a few inches deep inside you.
Also, a simple hack to increase your oxygen purity and performance - run the concentrator at max throughput for the desired pressure/purity, then use an overpressure valve(of the not-safety variety) to backfeed the waste oxygen into the inlet when you close the valve on the torch. It helps increase purity when you're not using the concentrator at its limit, which for most small glassblowing will be almost never, unless you use extra torches/burners. It also helps unload the sieves, and since it's already been through the system, extends the life of the air dryer.
Even the pressure rated pvc is only rated for use with noncompressible fluids, which release minimal energy when decompressed. Metal would be much safer.
I hadn’t known about pressure-rated as distinct from schedule 40/80; he said he used sched 40. (Or were you just referring to one of those two, as opposed to PVC drain pipe?)
@@DaveEtchells Yes, sched 80 should be used. The other commenter is also correct, neither is rated for compressible fluids, so I would use something like HDPE/PET pipe instead, but it might be a bit too expensive.
Schedule 40 and 80 is enough for 40 to 60psi easily. If you have ever seen a potato cannon built from Schedule 40, you know the psi that it handles far exceeds 40 to 60psi. Not saying it was meant for that application but the low pressure he is using of 40psi is reasonably safe for the pipe he is using. I don't think it will fail any time soon aside from hitting it with a hammer and cracking it, it should easily handle that pressure. Just going off real world testing and experience. Nothing scientific about it, but it has been tested and 40psi is acceptable for these pipes. If you find one that fails at 40psi I would love to see it. The water rating for schedule 40 on 3.5in is about 240 or 260psi. So it's a decent margin.
I think something to have in mind is the pressure swings can induce significant material fatigue so i think the tanks should have a large safety margin on their pressure rating to compensate for the cycling stress.
I usually don't interact much on youtube but wanted to leave a comment because your channel is criminally underrated. Great production value and extremely interesting projects, keep it up!
I'm new to the channel and 30 seconds in after seeing the thumbnail.
I think I'm going to agree with ya
At the beverage company I work for we’re installing a large one of these to create a pure nitrogen gas flow to replace Co2 in some of our processes.
Oh that's cool! Yeah, I looked around at the websites for some of the companies that design PSA plants for manufacturing environments and they get pretty serious!
So nitrogen infused beer is what you serve up? I'm just guessing but it has been a trend in the past decade or so. I know other beverages use nitrogen as well now. So does the nitrogen work the same way except you use the exhaust instead of the oxygen ports?
Don't drink nitrogen infused beer. It will contain nitric acid which can dissolve 10 meter of concrete when placed in Wyoming!!!!
@@newmonengineeringSame way, you need to use a different Zeolith that traps Oxygen
@@newmonengineeringThe Nitrogen is probably for flushing the storage tanks, you dont want beer to come in contact with air since it can effect the taste. So you need to flush out all the air with some other gas.
When I clicked on this video I wasnt sure what to expect.
It sure wasnt Bad Ass Applied Technologies, but here we are and I must say, you do a great job explaining things.
I really love that this is built on a typical hand cart!
EDIT: I'd love to see if the atmosphere input would benefit from a heat pump drying pack as is found in a system like the GE ventless Washer/dryer combo....
EDIT 2: You've got me so hooked in with this vid that I keep thinking of things to say...
For the sensor hookups that you've yet to use... I bet that data could be integrated as feedback into a controller that gives a more steady/efficient output!!! I'd LOVE to see a video about that!
lesson learned, always throw in an extra audio recorder as a backup
I never heard of the Oxikit, think I will build one but just use my shop compressor. Never fails my oxygen tank is empty when i need it. You did a really good explanation of how it works !
You can clean out and use a condensor from a car air conditioner, got mine from junk yard. Far more efficient than the copper pipe. We get a lot of high humidity days so water in the compressor tank was always an issue for me. I run the output of the condensor into 2" black iron pipe that is jacketed with 4" PVC pipe using rubber couplers. It's filled with coolant that circulates when compressor kicks on. It's rare I ever have water in my main air tank since making that. I have a 60 gallon compressor so you may be able to scale down the size of the pipe and still catch a lot of the condensation.
Keep in mind needs to be oiless compressor you will distroy the zeolite within hours of use. I built mine for no more than 400 I’m using the same compressor only mine is 1hp I bought rebuilt off eBay from California tools I got 2 compressor and 1 yr warranty out the door for 115$
Through trial and era I’m actually doing to 2 unit on the same cart which I convert a old dewalt 2hal hotdog coprocessor frame just kept the frame and tank. I’m learning to blow glass some no such thing as to much oxygen lol best of luck let me know if I can answer any questions
Another thing to note because I didn't hear you say it in your warning about breathing this air: make sure you are using a specific breathing air air compressor. Most air compressors, even oil free ones, are not meant to make breathing air and can be dangerous to breathe from. There are specific kinds of air compressors for these applications you should look for
Absolutely correct. But unless you're part of a national emergency like COVID was, I would simply not use DIY to make O2 for ANY use that involves HUMANS (or pets) breathing the output. There are simply too many potential health threats that could emerge.
Honestly if anyone is looking for one for medical uses they would be far better off finding a used medical unit, it's not very hard to find units for $100 or less in most populated areas. The best way is to set up search alerts on craigslist and facebook marketplace, in my area (near Detroit) functional units under $100 pop up about once a month.
Your actually about 20% correct many OxyCon company use the exact same compressor they just use 3 different filters before you breathe it but if ya paid attention this is for industrial use and not medical… copy ???
Have a nice day
@@natemaddogtrikejones181 he specifically made a warning about breathing the air so I made a comment with an additional one
I'm not sure why YT graced me with this video, but I'm glad they did! Great project, great video format, and that got you a new sub. 👍
What a wholesome build, and great quality of the project and everything. This channel deserves 10x or 100x the audience and I am so glad the algorithm sent me here!
I want to make a really small one of these but in reverse, you can make a fairly inert nitrogen supply using the same hardware. It's total overkill but i want a nitrogen purge on my soldering iron. 😂
I've started to look into what it would take to collect the purge gas from this machine and dry it for similar purposes (filling my high vacuum equipment when I bring it up to atmosphere)
@@SignalDitch How oxygen-free is the waste nitrogen stream? Good enough to use as an inert gas purge for food storage?
Awesome video. May the algorithm favor you.
That's a damn nice project - should get you going with those oxy-propane burners for sure! I really like the pneumatic and automation design, and placing it all on a dolly is very practical too. Take it right where you need it :).
Err, that's a hand truck, not a dolly.
For something that got randomly recommended to me on RUclips this is great stuff! Love the content!
Really interesting project. I've saved it in my playlist, passed it on to a couple of mates to watch and subbed.
I appreciate it, glad you enjoyed!
I'm always surprised on how precise you choose topics that have my main interest. That's something awesome with you. You disappear and when you come back it's with something really big. Really thank you.
It reminds me by the way of the glass lathe project. Are you still on it?
Never thought anything good would have come out of Covid. Nice video.
As always, a great video and an impressive build! I also wanted to build a concentrator, but considering the fact that you can get used medical devices for very little money, it wasn't worth it for me. However, if you need a very large or modular concentrator, a DIY build is certainly the better option.
Regarding the oil-filled pressure gauges. I thought the oil doesn't come into contact with the gas (if the pressure gauge is intact). Or am I mistaken? Of course, it's still better to completely avoid (regular) oil in a system with oxygen.
Anyway, great video!
Thank you!
It has become more difficult to buy a used oxygen concentrator in the USA because medical oxygen is controlled by our FDA as a prescription therapy, and they began strictly enforcing this during COVID for fear that people would use unprescribed oxygen unnecessarily and injur themselves. It used to be very easy, with listings for used concentrators often showing up on eBay and Facebook marketplace. I don't mind breaking the law, and I would happily buy someone's used machine, it's just that they get delisted from marketplaces now. This is why whenever I talk about this project online, there is an army of people who tell me, "Just buy a used medical unit 5head"
Regarding oil-filled gauges, you're correct that the oil should never normally come into contact with the process gas. I think I had a take where I said that, and it got lost in editing. As you mentioned, though, it's best to avoid any scenario where oil and oxygen could mix under pressure. Ideally, all of the cheap pneumatic fittings would be washed in degreaser to remove any oil, but I didn't go that far.
I appreciate the comment, and I'm glad you enjoyed the project. Your videos are always a treat!
Nice little project. Here in the UK, I'd call the trolley a Sack Cart.
or a sack barrow.
@@martinhow121 Ohhh not heard the barrow before. Mind you I'm up North, so maybe a regional thing?
Amazing! Missed your content!
15:40 It's been so long since i've since someone reference steve1989 ! Love what you made, this is a really cool apparatus and professional-grade ! I woukld have added put the safety valve right side up because i don't think having water standing in it is very good for it. I'm curious about the performance of it !
Also, even pressure-rated PVC will have fatigue stress, i've seen a video of a guy doing his DIY water/air separator/dryer combo system entirely out of pressure rated PVC and it had a rapid unscheduled disassembly after a few thousand pressure cycles. At 30 psi it may take a very long time and it will not be extremely violent but still, you need to be careful of it when it happens. Maybe wrap a couple turns of tape aroud the tubes to be extra safe.
Steve is the man! Both "nice hiss" and "let's get that on to a tray" come up surprisingly often in my day to day life.
You make a good point about the safety valve, I didn't think about that, it's easy enough to take a wrench and turn that upright. As for the PVC fatigue failure, that's interesting, I didn't consider the effect of pressure cycling. I'm not convinced that 30 psi hits the threshold for that type of fatigue to set in, but maybe with oxygen embrittlement(?) I could see it. Yeah, maybe I'll wrap a few turns of tape around them or put a big piece of techflex over each one to contain them when they do fail.
It seems safer to do that than to try to wrap them in composite or something to try to prevent them from failing.
Cheers
I was hoping someone would bring the steve1989 reference up
@@SignalDitch From what i could read, PVC is quite resistant to oxygen, embrittlement is mostly a problem with flexible PVC by degradation of the plasticizers. Also at 30 psi, you're at 15% of the rated (static) pressure of a 3" schedule 40 so you might be good, but my motto is better safe than sorry. Especially with oxygen, where a leak when you have a flame nearby is going to have far worse consequences.
Always great to see creators taking feedback from the community ! Stay safe out there.
Hell of a project to pull off! Great video, great project, well executed and swiftly but accurately described. 100% subscribed!!
Very very interesting! I was a little lost on your diagrams of the machine, i didn’t get time to find the bits you were talking about, if you highlight your mouse you could use it as a pointer to point to the bit your talking about, which would help the older folk like me :) this was an awesome project. Very very well done bravo!
I appreciate that, thank you!
I'll try to keep this in mind for future videos. In the meantime, you might enjoy looking at the diagrams and illustration in my blog posts on the project. There's a link in the video description.
Very fascinating. By the way, you remind me of a college friend of mine who was interested in technology, math, and AI.
He passed away in his mid forties, unfortunately. You could have been colleagues.
Pro tip- fill the copper pipe with sand....if requiring to create nice round, tight bends or loops. Shape the pipe with the sand filled within it. This will almost completely remove the chance the pipe will crimp down on tighter bends.... you will have nice and smooth and round piping...remove sand when finished.
Good video. I enjoyed it and all that you went through. For many of us we may not need as much O2 and therefore may be able to use a used oxygen concentrator. The thing is that your video highlights the internal workings of these concentrators. They use the same mechanisms. Your video should be helpful as well to anyone that is using an old medical O2 concentrator for soldering or brazing.
Thanks, yeah, that's my hope! It made sense in my circumstance, but it's definitely not practical or cost effective for everyone.
Subbed. Love it when I find gem channels like this.
That was cool, exactly the right kind of needing out for me. Subbed!
Lol the moment you started talking about Oxygen you choked your mic! 😂
This is really cool thanks for sharing 😊
Very cool project! I’d known about oxygen concentrators using zeolite, but had no idea of the details!
love this i have a thing from a nitrogen generator its a tube with a sensor that is suppose to tell you what gassed in ppm are in the flow, its yours if you want it
Very cool.
Thank you.
Dalibor Farny built a larger version of this for his oxygen needs at his nixie factory; he has some videos of it on RUclips.
His video was an excellent reference during this project!
Excellent. 👍
Interesting. I knew about molecular sieves but it was interesting to see a detailed breakdown of your build.
Yeah, they call the machine an oxygen concentrator but really it should be called a molecular sieve babysitter. The sieves do all the magic!
Super cool build my friend!! I sourced a used oxygen concentrator and I have been doing research to see if I could substitute larger size zeolite beds. You did such a fantastic job making this video and I am so glad to see you back to making content. I was also able to find a nitrogen "generator" like the one Grant used in the king of random build . I have been busy with other stuff but you have been a n inspiration!!! Thank you so much. Are you in New Jersey? I am in Pennsylvania....My grandfather was friends with an incredible man named Don Smith. Don developed some incredible inventions that revolutionized the way we generate or "energize" power. When Don and my Grandfather were alive I was going to pharmacy school but then became disillusioned with the way medicine is going so I decided to go for my Biochemistry degree. After that I got my Master's and PhD in Chemical engineering. I have recently gotten back into the conversion of atmospheric static electricity into usable dynamic electricity. If you are anywhere near me (outside of Philadelphia) and are interested in what I have accomplished we should get together. We have many of the same interests..lol
I'm actually all the way down in southern Virginia! I'm glad you liked the build!
Hey John I was really interested in your text about mentioning Don Smith. Very much interested in some of his technology I see that your grandfather was good friends with him. There's so much conflicting information out on the internet at some of it has been disinformation.
I've been trying to follow some of his techniques and ideas. I have some books as well.
Have you done any exploration in Don Smith technology??
I really would like to get to the bottom of the truth.
Could you help out??
@@sirblingjax Absolutely my friend! here is a working device. I have pictures and schematics for a bunch of running devices.........ruclips.net/video/FBhXEm24vP8/видео.htmlsi=y_p1X2ZheoJYqBL0
This video gives me an idea that might put me on a watch list.
Say you have a large amount of uranium hexafluoride gas and you wanted to purify it to get some U-235, could you not pressurize the gas through zeolite of a certain pore size to trap just the U-235? Sort of like how a centrifuge works, just line up loads of these connected in line and just keep running them in a cycle until all that's left is U-235.
Btw, I love your tats!
Yeah, I'm not sure if there's a zeolite that has the selectivity you're looking for, but there are processes that do the same thing with ion-exchange resins. Molecular Sieves _can_ be used to separate U from other stuff, but it would have to be pretty exotic to affect isotope separation, I think.
Either way, I hope you use your danger rocks to make clean energy instead of **checks notes** murdering thousands of people.
@SignalDitch all I want is the nuclear powered car that I was promised in the 60's, is that too much to ask? lol
You should soon hit a well deserved thousand likes with this video very interesting 👍
Glad to see you :)
This is the first video of yours I've seen, and I'm only two minutes in, but I love it! Instant sub. Also you look futuristic as fuck, it's great
Great video.
Great video! Thanks very much for sharing and especially for the wonderful, high-quality video and narration! Liked & Subscribed!
AND thanks very much for the added information in the video description text which fleshes out the narration and clarifies some key points.
Great project! Love you in Highlander ;)
Since you seem to care about safety: the blue to pink desiccant starts out a real nice cobalt blue color, because it has cobalt in it. Keep track of which plate you use when drying it in the microwave 😅 (I don't know if this is universal, but the legal-in-Europe versions without toxic heavy metals are different colors. And aren't as gorgeous when dry as a result.)
That must be why they taste so good!
lol you'd have to ingest a LOT of silica gel to get poisoned from the amount of cobalt chloride in there. That said, heavy metal exposure is usually cumulative so I'm not against being mindful of your exposure. I have a little 700W microwave in the lab with labels all over it that say "NOT FOR FOOD" and there's a little pyrex dish I use just for the task 👍
I need one of those for my shop!!!
Fantastic build mate, practical if a little complex, solution for a real cost. What is the rough hours of use to pay back the system I wonder? Also just a thought if that condenser safety valve would be better upright to reduce risk of it freezing shut?
Thanks!
That's a good question, I don't think I can know that until I find it what the maintenance cost will be e.g. replacing zeolite.
As for the safety valve, I think you're probably right. Someone else has brought that up as well.
Very nice!
I used to work on these systems for industry for both O2 & N2 for diving or laser cutters.
I would add a bigger buffer tank as piston compressors are designed with 50% duty cycle so 50% working then cool down to get expected life span of 3 years which is not important if you treat the compressor as a consumables!
Hey, I appreciate this. I had the same concern when I was initially evaluating the Oxikit project. The manufacturer recommended continuous runtime on the SP-9421 is actually 30-60 minutes with a 70/30 duty cycle. Considering I'll rarely run the torch for an hour straight and the compressor isn't exactly getting a hot supper here (max system pressure 30psi), I'm not too worried about it. I do have forced air colling on the radiator fins for the compressor heads, though.
A larger buffer tank would be nice but it would have to be _much_ larger at only 30psi to supply 15lpm+ for a 30% off cycle.
Well done, mille gracias. Subscribed, bell rang, commented, liked, upvoted, shared ... may the algorithm gods smile favorably upon your channel.
I'm glad you're back! 😁
This is awesome. Inspirational stuff, thank you. But I wonder, for US$1500 in parts and materials plus the amount of hours I would have to put into this to get my 20 litres per minute of oxygen… say it took me 80 hours to complete. In my experience, things take way longer. For example, I study the plans and endeavour to understand the science, do drawings, and spend time thinking and visualising, I search online for the parts, usually from China so they are affordable, but also I need to wait a month sometimes for delivery, then I do the fabricating, testing, changes, upgrades, maintenance, etc. But lets still just say it took only 80 hours, Multiplied by a low hourly rate of 30 bucks per hour, Equals $2400 plus parts $1500, Totals $4k ! Then I look around online and discover I could buy 2 or 3 of the commercially available 9 litre per minute O2 Accumulator Machines, that are quite small and cost US$250 each, that I could plumb together and mount them to the same trolley you have to give me 27 litres per hour. For a third of the money and all that time saved that I could actually spend on practising my glass blowing skills and buying borosilicate tube.
I made this very mistake when I made 3 or 4 versions of a large HHO generator cell for welding gas, spending hundreds of hours and eventually succeeding but not with a super reliable machine, and its currently broken! I found a company in Russia that makes pretty much the same thing for the same money I spent on materials. Which will be under warranty for 2 years and reliable. And the manufacture answers my questions. As a bonus I achieve actual results!
So, although making stuff provides invaluable knowledge of materials and fabricating, inventing etc, which I am personally wired for and love to spend time with such, doing a feasibility study prior to commencing a project such as this, and being brutally honest with yourself, is very important.
This is a great lesson for somebody who makes things to learn. That being said:
1) Assume you have another goal, which is to grow your RUclips channel and consider which solution is more interesting to watch.
2) "...then I look around online and discover I could buy 2 or 3 of the commercially available 9 litre per hour [sic] O2 Accumulator Machines, that are quite small and cost US$250 each,"
Did you try to buy them? Or did you just see them for sale? Because those are different things as I discovered last year.
3) I enjoyed doing it. I could also just, you know, buy vacuum tubes. It's pragmatic to do a feasibility study if you're concerned about "productivity" or "efficiency" but this is literally just the stuff I do in my free time to keep me sane.
@@SignalDitchThanks for your reply SignalDitch, re your 3rd point, there is probably is no better reason for the makings, I am there with that but I have time constraints and budget to consider.
Re your 2nd point, I fixed my [sic] but maybe this wasn't far from the truth, and no, I've not seen one or used one. Are they terrible? Your honest opinion of them would be great to hear. I met a glass blower close to me (South Island, New Zealand) and she has a small medical O2 Accumulator filling a huge mofo storage tank probably 3 feet across and 3 high that she pumps 24-7 into (didn't get into the details of modifications, pressure shutoff, flashback, etc). And although she might only do a couple of hours of Lampwork per day, it suffices.
And to your 1st point, I totally dig it. Its just that people watching may not consider this. I was sharing my views from the point of view of a full time artist/designer/inventor trying to make his way in this bizarre ol world, efficiently. Speaking primarily to other makers that don't have so much skin in the game and meaning no ill toward you all. Its actually awesome and unexpected to get some solid responses from a content creator.
Hand truck = sack barrow 🏴🔧👍
Thats clearly the bomb from Rainbow Six Siege
It's funny that you said that you normally don't pressurize PVC with air usually you pressurize it with water understood yet when I have seen several people use PVC half inch PVC for their compressor for their entire shop and if you read on the PVC it says 600 PSI so that's well over $150 and that's all air compressors ever go up to is 150 I had one air compressor that did 300 but it did 300 on the compressor itself supplying an entire shop with a three tank unit 2 pressure cylinders each with its own compressor unit and a main supply tank that stated a constant 150 psi. And it didn't matter how many tools we were using in that shop we had four bays one air compressor
EXCELLENT
I'd like to see a follow on stage for concentrating the Nitrogen and Argon.
I would also like to use the nitrogen! Maybe I'll work on that
@@SignalDitch to use this for nitrogen concentrating, look at using carbon molecular beds. It’s also possible to concentrate nitrogen using membrane concentrators. These hollow fiber membranes are pricey but sometimes available used on eBay. They’re currently used a lot for automotive tire filling stations.
@@en2oh Thanks for the tip!
Hey that's a Sack Barrow in NZ
Wow, it sounds like sack truck or sack barrow is the word in every other English speaking country just about
A minor correction on your explanation of how the zeolite works to separate air: the Li or Na-X zeolite you are using does not separate O2 and N2 by molecular size, it separates by the N2 sticking to the Li or Na ions in the zeolite more strongly than do the O2 molecules. It is an "equilibrium" separation, not a size-based or kinetic separation.
That's fascinating. I knew that Li/LiAgX zeolites outperformed NaX in O2-N2 selectivity because of electrostatic and ion-exchange interactions, but I thought that was just enhancing a mechanical adsorption effect. I see now that ion exchange is actually the whole mechanism. I'll read up on this because it has interesting consequences for the questions people are asking about, for example, Ar-O2 selectivity. I'll address this in the follow up video, thanks!
Very impressive and interesting project. Did I miss the part of the clip seing the system run and any words said about the amount of output?
Awesome
Subscribed and looking forward to more of your content. Great video!
Return of the king
I think PVC pipe can hold 80 psi safely, but it would be easy to test a piece to bursting, Your build looks nice. I would liked more details on psi or perhaps showing how big a torch you can run with the system. Also how much sound the system generates at high load. I always wanted to make one, but i also want an oxygen compressor to fill a tank (so i don't have to listen to the compressor running forever).
I'm working on a torch manifold that probably isn't worth a whole video, so when I film that, I'll try to address some questions about this project. What is it you want to know about psi? I'll do some tests about flow in the meantime.
0:42 propane and propane accessories
You make vacuum tubes?! Im sold! I wanna make them too!!!!!!!
In the UK your 2 wheeled dolly is known as a sack truck . . . probably among other things.
I like that
💡Watch offer-up and occasionally you'll find used medical oxygen concentrators for as low as $50 and sometimes even free.
I think I have almost everything i need to make this except the zeolite. Don't see the need for the Arduino though, just some simple timers can do it
Yeah, timers would do the job fine
@@SignalDitch running it thought in my head, just a 555 and a pot to dial in the cycle time. Probably going to order stuff this weekend and see what foolishness I can deliver.
The amount of details was very well done and extensive
I’m not an expert in fluid or gaseous systems but could it possible to keep/save/store the Nitrogen output and to use it in other projects were you need it for is inert properties?
Theoretically, yeah you could! I've been looking into whether it's practical in my shop because I could use dry nitrogen for when I have to leak up my high vacuum equipment.
Cool, I was thinking about inert gas for lasers cutting / CNC
I’m wondering if the risk associated to fire hazard by a system failure pushing oxygen instead of Nitrogen is too high
That's a good thought. I suppose you could put an in-line oxygen concentration sensor behind a buffer tank so if it detects more than a few percent of O2 it can trigger some valves to shut off the shielding gas line, dump the buffer tank, and e-stop the cutter? Not sure if it's worth it, but might be fun anyway
Thank you for the video. My interest is for nitrogen and wondered if the exhaust output is sufficiently pure nitrogen for oxygen shielding in welding application, or is there a more economical alternative method for removing oxygen?
Amazing video!
so fliping cool
Some applications may want the low oxygen (N2) output discharge. I have an amazon plasma torch for cutting steel/aluminium/stainless. I am a NOOB with this type of tool. It would be interesting to see if the low O2 air would work well for that application. I noticed when cutting SS that there was a lot of oxidation in the cut. Who knows....?
Sweet! I wonder if there's a cheap way to pre-desiccate your air so your dryer doesn't saturate as quickly, using crushed ice? Air that's flowed over crushed ice has very low absolute humidity (at least once the fog droplets have separated out). Maybe a cooler full of crushed ice, with a perforated false bottom to create an air plenum? Honestly not sure whether this is actually more convenient than just regenerating the desiccant though, that sounds pretty easy and ice is a consumable one would need to go get.
I think you could use a few tanks of desicant. Once one tank of desicant is too full of water, maybe it cycles with reasonable warming coils to purge the water out.
Would a version 2.0 include an air conditioner in the path of the air you are ingesting help? I know a/c is great for dehumidifying , and my brain is trying to fit one in after your dessicant issues in the SE USA was noted. They make portable A/c units that you could pipe the output directly into your intake potentially. Likely overcomplicating your design, but I thought I'd ask anyway. Great video regardless.
hi thank you so for the amazing video and all the info can you pls let me know if i can use 6 mm od copper tube instead of 3/4 9.5mm like is mentioned in oxikit website i live in a city Humidity: 69% according to google im just rebuilding a Concentrator that i found in flea market im using it to get the parts i need because everything its expensive if i want to by all new part thank you so much
Hey man, small suggestion and i don't know if i just missed it. But it looks like you're going to have live mains on the screw terminals on your rail there. Might be an idea to cover those, i know right now you'll be careful around it but in a years time if someone brushes against it they could have a bad day.
Those screw terminals are pretty well recessed. You'd have to really jam your digits in there. But your point is well taken, I'll probably print some nice covers for the wiring before the next time this thing appears on video 👍
do the little portable oxygen generators some people use work on the same concept? On my submarine the air dryer for our HP air works on almost the exact same system but is using desiccant instead of sieves and in manually changed over every couple of hours.
I'm fairly certain this is the principle behind most if not all medical oxygen concentrators, even those little purse-sized battery-powered ones. Interesting to hear about your air-drying system. Yeah, PSA is used for a handful of things besides oxygen separation depending on the media in the sieve beds!
So with very little modification, couldn't you extract the nitrogen exhaust and pump it into an air compressor and have NEA. Maybe have another stage of zeolite to get closer to N2 in your air compressor.
2 bangs 1 buck.
N2 and O2 in separate containers.
Yeah, in theory, you could certainly do that
0:05
*the audience members who have started running by this point will survive the encounter.
Cool project well explained, nicly put together in a compact package. Do you think that would have enough flow for cutting? I suppose with a larger filter and acumulator it could up flow rate.
In the UK we would call your trolly "sack trucks" (point of interest, not a criticism of some bullshit UK terminlogy vs North Ameriacan termnology).
P.S.Love the tats on your fingers. I always fancied e^i pi as in a preveosue life I was a mathermetician for a few years post uni.
P.P.S. Excuse the spelling Spell check has stopped working on youtube comments for me!
Can we get rough specification, to get an idea to which applications is this Oxygen Concentrator suitable? Mainly I'd like to know
- power consumption
- volume/min of oxygen on output
I don't have a great way to measure the volume and concentration, but enough people have asked that I may spend some Patreon money to get a cheap sensor.
That said, I would refer you to the oxikit documentation because this is essentially a 1:1 implementation of that project. They claim 20 lpm+ at 90%+ concentration.
As far as power consumption goes, I haven't measured but if you need a rough ballpark, the 2HP electric compressor motor is probably a good place to start. Probably a few kW? 2 or 3?
Very interesting project.Would it be possible to use this system via combustion to produce purified Co2 for MIG welding?
DIY CO2 is often from fermentation as there is hardly any in air, people use it to feed aquatic and other plant nurseries. I think removing moisture would be a thing to solve. This type of adsorption system is generally used for O2 or N2 concentration because they are 78+20=98% (+-) of the atmosphere.
maybe a stupid question: couldnt it cause problems for the over pessure valve to be flooded all the time ( the bottom one seen at 18:00)
Not a stupid question at all, someone else pointed that out as well. Theoretically, not a problem. It just sprays water on overpressure, it's made out of brass so it won't rust shut. Practically? I don't know what the spring is made of, so it could kill it over time but at least it would fail open. The verdict? I'll just give that tee a half turn so the valve is pointing up, lol
Any idea what the lpm of output is? I'm curious as to whether ones of these could run a glass torch. Super cool build!
Thanks! I'm still testing, but Oxikit claims it's around 20, so probably nothing _much_ bigger than, say, a Carlisle Wildcat.
@@SignalDitch Gotcha. Once I get setup again, I have a Delta elite, so definitely need more than that. Still, might be possible to hook this to a tank for a home fill setup. Though at that point it's probably worth just buying an oxygen frog. Still super awesome that this is now an accessible open source project!
I wouldn't want to breathe it either without a CO sensor on it. Compressors can make that, as I'm sure you know.
I have never heard of generic air compressors causing chemical reactions or any sort. The most common source of CO is incomplete combustion. Where did you hear/read about the CO issue? None of the medical units have any CO mitigation features, the better ones measure the O2 concentration and give an alarm if it falls below set level (90% probably).
I bought a medical oxygen concentration system for my glass shop last year i wonder if this would have been more or less cost effective.
If you got a good deal on it and it's been working for you then you probably did well. Part of the audio I lost in the microphone issue was me explaining why I decided to build instead of buy and I still recommend buying if you can and if you know how or are willing to learn how to service the commercial one.
Is there a way to measure the oxygen percentage / purity?
For somewhere between 100-200USD you can get a "cheap" version of the little machine that's used to test medical concentrators. Electrochemical and ultrasonic sensors can both be used to determine oxygen concentration in air.
If you're clever with chemistry, you could probably come up with a bench test that has to do with bubbling a known volume of gas through a solution and then weighing the solution, or a precipitate therein.
For my purposes, it's good enough that it can completely combust the torch fuel, but I may do some testing with a flow meter and a purity meter when I can afford it.
For reference, Oxikit claims to have tested the design that this is built from to 20 LPM@94%
Great vid and project , those indians ,get things done with minimal fancy expensive 'stuff ' . My question is how does oxy-propane welding perform cf oxy acetylene , as you say the renta bottle crowd have priced a sometime user out of the market .
I can't say specifically because I mainly work glass, but my understanding is that propane requires more O2 per unit of gas and never gets quite as hot. That said, people run cutting torches on it, so i guess it works.
@@SignalDitch Ta , hopefully people are trying it ,will have a look , but looks like you were getting a good colour of flame so no hydrogen embrittlement , the main problem so far as I know , after that heat is heat me thinks . and had to chuckle at your factual breakdown of air , not even mentioning the huge boggy man of CO2 ,as it is a miniscule % ,which plants need ,so we do too ,but the idea of it being hazard is total bunk ,actually funny , we would stop breathing if it wasn't there !?.
A number being small without context means nothing. You must understand that no one is saying that all CO2 needs to be removed from the atmosphere. Anthropogenic climate change is a verifiable scientific reality.
@@SignalDitch Hmm, there are in fact lots of people and programs that are champing at the bit to remove CO2 from the atmosphere and expecting to get paid from taxpayer resources, the term is carbon capture, and they do not even recommend trees. Before you categorically repeat that last statement as fact I do urge you to have a look into the percentage of the CO2 in the atmosphere that is due to human activity. Check also how much the CO2 is consumed by sea plankton.
Always remember that if a single climate summit is held in person the premise is a scam, you do not fly to a place to talk about reducing CO2, so far I think all of the summits have been in person.
I am not saying you are wrong but my understanding of the facts does not match yours and it is unlikely that we are both right.
Great video and really good answers from you except for this one that suggests failure to discern propaganda fully.
I am looking forward to your glass lathe progress as well, I have similar dreams.
Similar dessicant dryer on the air input line mau help.
He uses the coalescing filter after compressing and cooling the air to raise the dew point to get 'free' water removal before consuming space in the desiccant. Chilling the compressed air a much as possible enhances the water separation. Some dental compressors (these would be a great source of dry clean oil free air but are way more expensive than commodity compressors) use a membrane separator that I expect will be more effective than the sintered metal or packed fibre trap in the coalescing unit.
I have two old medical oxygen concentrators I want to convert into an oxygen generator.
Is the output sufficient to run the torch with Acetylene and cut steel with it?
Theoretically, yes. Propane actually requires more oxygen for complete combustion than Acetylene.
There are some videos that another commenter alerted me to of a guy cutting steel with an oxy-propane torch and oxygen that he compressed from a refurbished medical concentrator. He was having issues (I think due to the condition of his concentrator) with the cut quality.
Is there a way to adjust the cycle to output lower oxygen content at higher flow rate?
Theoretically, yes. Shorter cycles at higher flow should result in lower concentration.
@@SignalDitch that would be very useful for some applications!
Wouldent a one way valve be usefull right befure the buffer?
Maybe!
For many ears I wondered if one of the health related oxygen concentrators would work for providing oxygen for brazing or soldering. I just did a quick Google search and found a home units that deliver 5 liters per minute (5 LPM) for $550. In fact there a number of them in that class for as low as $300. How do I find out if that is enough oxygen for a given size of torch?
Some manufacturers will give recommended flows and pressures for their torches. Alternately, if you already have a torch, you could just measure it with a flowmeter from an O2 tank.
5lpm is just enough to run a very small torch (look up the Smith Little torch) you really need 10-15lpm minimum to do anything beyond jewelry. You can chain the outputs of multiple concentrators together, though! If you can really get you hands on those medical concentrators, they're not a bad deal. If you're in the US, beware that many of the legitimate listings have been taken down as the FDA cracked down on the sale of Class II medical devices without a prescription during COVID.
@@SignalDitch Tnx for the info. It seems that for the amount that I need and as much as I would use it, buying a small tank and getting it filled will probably be the most economical option.
LOL; that's almost exactly the same as the system a place I worked at had to fill pipes with nitrogen. I guess it just depends on when you save the gas & when you just dump it back to the atmosphere. See South-Tek N2 Blaster. Maybe you can save bot the N2 and the O2. But how about all the other 'impurities' like CO2, CO...
Yeah, that totally makes sense, it's just a gas separator, so depending on what you "keep" it's either a nitrogen concentrator or an oxygen concentrator, lol.
As for impurities, CO2 and CO make up an incredibly small amount of atmospheric air. That said, they're reactive, so you can remove them with chemical scrubbers or catalytic converters. The hard stuff to separate is the noble gasses. Some zeolites have an unbalanced Ar-O2 selectivity, so they could be used to progressively separate the two after a series of cycles.
I love your tattoo's!
Thanks! My head piece was done by Brad Wooten, if you like the style you should look him up!
hmm, i wonder if you could use this concept to safely gather methane from the open air? There are so many places were methane is burned on sight with no gain just because it simply be bottled
I looked around and there are some papers on it. It seems like PSA is used a lot to separate Methane/Nitrogen mixtures.
Like most problems, I don't think there's a technical barrier to capturing methane right now, just a capital barrier.
Antifa, vacuum diode hackaday, professional content, and only 5k subs??? What a travesty! You're wonderful.
if the zeolite is dangerous, how will that be great for hospital? How do you know you got it 100% out of finished product? Just a filter doesnt give me 100% assurance.
This is the way that almost all on-premise medical oxygen in the world is generated (bottled oxygen is often fractionally cryo distilled) It's only dangerous because it's a rock, and breathing rock dust is bad. A mechanical filter is the best (and only?) way to remove it. We're talking about relatively massive particulates in the world of air filtration.