Thoughts on Oxygen Generators....good idea?

[MasterJoey05]

I am looking into buying an oxygen generator. I have been looking at a few and was wondering which one to get...or if its even a good idea. I like the idea of not having to use oxygen tanks but I'm not sure if the generator will supply it to the torch just as well. Does anyone have experience with these that can give me some advice? I want to run a Bethlehem Alpha on a generator and will be making small and medium size boro stuffs

[Captain Glass]

I just ordered one yesterday from unlimited oxygen for my lynx

[MasterJoey05]

Witch generator did you order?

[Captain Glass]

An m20 from unlimited oxygen I think it would prob run your torch too but don't quote me on that.

[Captain Glass]

Just checked and I'm sure an m20 would run your torch with ease

[MasterJoey05]

thanks!

[sevendeuce]

Did you buy an m20? If so how does it run?

[PyroChixRock]

Hey joey, welcome to TMP!

[talonst]

I had an OG-15 that I used with an Alpha for a while, but I found that I could only really run a small neutral flame with 1/4" candles, which leads me to believe you would need 2 concentrators to have enough O2 to run larger flames or oxidizing flames.

Personally I'd recommend tanked O2 - it takes all the variables out of the flame chemistry accept whatever you're doing at the valves.

[kbinkster]

Tanked oxygen (and I include liquid as "tanked") is always going to run your torch better than a concentrator. You can crank up the flow/pressure to whatever you want and the purity is higher. However, not everyone can use tanked oxygen for a variety of reasons (e.g., too expensive, not available, physical limitations that prevent them from dealing with tanks, etc.) and some people simply prefer the convenience of a concentrator (don't run out of oxygen in the middle of a piece or when the supply shop is closed) and are fine with the output for the type of work that they do.

The Alpha, as well as most torches that size, runs well on 10 LPM. You do not need a high delivery pressure for the Alpha. As for concentrators to go with it, I would recommend a Regalia, Integra10, or an Invacare 10 LPM machine. These are all well-built machines. The Regalia and Integra10 are the only two machines that will run the torch without flame fluctuations ("breathing") when run straight off the machine, plus, because the compressor is not stressed as much as with other machines, it tends to last longer.

[samoth890]

I have a hurricane from unlimited o2 and I like it a lot. Like kbinkster said, some people can't really use tanked very easily, and I'm kind of one of them. I drive a ford fiesta, so I have to outsource trips to airgas to my friends with trucks whenever they aren't busy.
However, the flame does fluctuate on most concentrators, and it isn't quite as hot or as easy to create a really oxidizing environment. Also, it's simply not enough to run my bravo 100%, center and outer flame. I use my hurricane for the center which is more than enough oxy for that, and tanked on the outer fire. And if I'm in a situation where my tank is empty and I can't swap it, my hurricane will at least run the bravo to like 60% capacity, meaning center on full and outer on kinda low.
Overall I'm very glad I have the thing though.

[quix]

I work on tanked, liquid and at home I have 2 homefills filling tanks. I can't tell the difference between when I am on liquid or the stuff I fill at home. Oxygen concentrators are a bitch to use unless you compress and tank the oxy they are generating.

[Raimond]

Welcome to TMP, lots of information here, be sure to use the search button and the "Similar Threads" section at the bottom of every page.

If exchanging tanks is a challenge and LOX is not an option then an OxyCon is your best solution. To make the OxyCon better for the dual fire torches, add a HomeFill and 2 or 3 used tanks. You will have the best of both options. With this setup, you are using tanked oxygen but for a lot less trouble and money. You can "Rage" the torch when needed, work all day and then fill the tanks while you sleep.

[talonst]

Humidity and temperature also impact performance. Oxy generators don't perform as well in cold. Humidity can limit the service life of the sieve beds. Larger purpose-built units often have air drying systems while the small medical rebuilds don't.

[kbinkster]

The large generators are expensive and they require oilless air compressors or compressors with oil filters to run them, which are also pricey. They also need air dryers for the feed air, and those start in the $700-1000 range. When you look at a large generator system like that, you're looking at starting in the $8,000-10,000 range to get all set up. This may make sense for some shops, while not for others. The High Volume systems, which is powered by smaller self-contained units, are a little less expensive, I believe. It's important to know what your regular oxygen costs are so you can crunch the numbers and see if a particular system makes sense for you.

If you cannot run tanked/liquid, and the large systems are not economically practical, a Homefill unit or the smaller self-contained units (which would include the medical rebuilt units as well as the industrial units such as the Regalia and the OG-20) could be made to work.

The problem I hear about Homefill-type units and systems like the Rix microbooster are that they break down more frequently than other equipment. If you are handy and can repair the units, yourself, this could still be an option for you.

It is true that temperature and humidity affect performance. All machines, large and small, actually do better in cold weather than hot weather. The denser feed air makes for a higher concentration of oxygen. With some of the smaller machines, the system may not operate below 40° F (and at that temperature, you may not operate so well, either). When the temperatures get into the mid to upper 90s, the air is less dense and the concentration of oxygen is lower. Humidity can affect the sieve material, so you want your feed air as dry as possible. If you are working inside an air-conditioned studio, a lot of moisture will have been removed from the air, already. Running a dehumidifier in your space can also help. If you have a Homefill station, remember that that is a concentrator running the thing and treat it as such. If you can have it filling in an air-conditioned space and roll your tanks out to your torch (or have long lines to reach the tanks), that might prolong the life of the concentrator part of the machine.

And no matter what kind of machine you run, keep the filters clean and don't smoke around it. Dirt/dust and smoke can get into the sieve material (zeolite) and stay there. Wherever it lands, it keeps that portion of the zeolite from grabbing nitrogen, thus decreasing your concentration of oxygen in the finished product.

[talonst]

Thanks for the clarifications on the cold weather issue - I was referring to winter type cold when your garage or shed might be 30 or 40 degrees and takes a few hours to warm up.

Air conditioners and dehumidifiers might not work if the shop space is being vented the way it should be. Most small units won't keep up with an 800-1200 CFM fan for very long on a humid day. A better solution could be to have the oxy concentrators in another room with conditioned air for the their input and then pipe the O2 into the vented workspace.

[Mr.P0rn]

I've done some research on this myself, and am also trying to figure out what to do. I have briefly talked to the guy who does the high volume systems, and he quoted me roughly $8500 to be able to run a 40LPM system. It seemed a little high, considering i saw Jack from unlimited post a new machine he has on LE recently that I believe was 30 LPM/25 PSI for $2500, and I know he can do custom solutions. I heard he is also doing some sort of homefill now, but He hasn't responded to my emails. Unlimited Oxygen does seem to be the most price efficient though, considering he will provide support and service for as long as you own it. I've been hesitent about homefills, because I like to have 3 tanks 251CU FT filled at a time, and I'm not sure how well the homefill could keep up with all of that.

[kbinkster]

Running the machine(s) in an air-conditioned/heated/dehumidified space and running a line out to the torch is a great solution if the distance is not great. The longer the lines, the more the pressure drops (and you need the push to get the oxygen through the lines and to the torch). Most concentrators should have lines that are no more than 12' from the torch. If you are running the oxygen into a booster system (holding tank and compressor set-up), you could run a higher line pressure and run longer lines.

[Raimond]

My homefill system is in my house with a 3 foot line to my tanks through the wall. The system intake air is temp and humidity controlled and the tanks are in the garage... Only works if you own the home. I have a fan blowing towards the system to ensure a good air exchange in that area.

[byron3]

Yeah mine has a 12 ' hose(inside machine & compressor), I did supply an American manufacturer of single wire wrapped hydraulic hose, get custom lengths up to .......................

[691175002]

Concentrators alone will never match tanked oxygen. Your flame size is limited and it is very difficult to get a strong oxidizing flame. Anyone who has tried both will understand.

I am, however, starting to suspect that the difference is pressure, not purity. Homefills/HVLP systems run at concentrator purity yet reportedly perform like the real thing. Most concentrators put out <20psi with the majority <15psi which is nothing compared to the 30+ many lampworkers run on tanks.

Plus I can't imagine an extra 4% of non-oxygen will wreck your flame chemistry, given that as soon as the flame has traveled half an inch from your torch face its probably half regular air anyways. Some torches also intentionally mix in compressed air with favourable results.

[Greymatter Glass]

hey joey, welcome to tmp!


53862

:p

[Greymatter Glass]

Yeah, I agree the purity difference is negligible. I've worked with torches hooked up to homefill systems, you can't feel the difference... maybe if the sieve bed is going bad, but a good concentrator will run 94-96% pure.

I always laugh when people tell me the only use "medical grade oxygen" for their torch because it's better.... Oxygen USP is defined by the medical industry / laws as 93% purity, more is fine, less is not. Virtually ALL of the oxygen sold in the US, medical or industrial, is from a liquid source, which will generally be around 99.8% pure oxygen. I fill my liquid tank off the same liquid reservoir Airgas fills their medical oxygen tanks off, and the same bulk tank the medical delivery vans fill their liquid tanks from. The difference, aside from price, is that the medical guys have to hook up a hose to their tanks after filling and test the oxygen and get a little print out of the test results to show it's >93% pure.


Back to concentrators.... I recently got hold of a pair of 5LPM Invacare units to run a Cricket. I suspect it'll only take one, but nice to have a back up. These make sense for someone who will probably be on the torch less than 10-15 hours a week, and use a small enough torch that one or two units will supply enough oxygen. For bigger consumption rates you're going to want some kind of tanked oxygen. The Homefill units and similar compressors are a kind of in-between solution for many. They do not have the same 100% duty cycle the concentrators have. They don't do well being run for 24-32 hours at a time that it takes to fill a 220-300cuft tank to 2200 psi. If you set them up on a pressure switch and use them to fill 1 or 2 tanks to 500psi they will last longer, the goal being to not run them more than 8 hours per 24 hours. Consider their intended use is to fill medical "E" tanks, which takes an hour or two per tank, but are allowed to rest in between. If you were handy with electronics you could rig up a cycle timer to the pump, and only allow it to operate on a 25% duty cycle. I haven't tried it, but I know you can buy plug in cycle timers from indoor growing suppliers. They have 2 dials on them, one is an "on" timer and one is an "off" timer. So you'd set it to be "on" for say 2 hours, and "off" for at minimum 8 hours between cycles... I think that would prolong their life greatly, but it might not keep up with your use. You could bump it to 50% probably, like 3 on/3 off. You'd want that on the concentrators AND the compressor... it would just power the system up and down if you're working or not, but if it keeps your tanks above say, 75 psi, you'd be fine. If you can arrange delivery of 2 full tanks to start with, even better.

On the bigger end, I've done the cost benefit analysis of installing a higher volume OnSite Pro-4 and Pro-8 in a couple studios now. In Albuquerque, New Mexico we pay around $0.11 per KWh for electricity and have a local air separation plant that can deliver liquid to end point users via a distributor MUCH cheaper than the price per unit I would pay to make it myself + cost and maintenance of a machine. It wasn't even close.... What I could buy for $1.00 per unit would cost me about $1.35-$1.40 per unit to make. That is going to be typical of most metro areas in the US. As you get into more rural areas without a good oxygen supply or if you live on an island, or have some kind of restrictive local taxes on industrial gases it might make more sense...

[Simian]

Thanks for the great info Doug. I am starting to investigate a better solution to the tanks I have to drive to town and swap out. Great info to consider.