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vpt
04-13-2012, 05:56 PM
How exactly is oxygen separated to be pumped into cylinders? Is it a portable process? It is possible I asked this before and can't find the thread.

loose nut
04-13-2012, 06:46 PM
One methods is to cool air down and compress it into a liquid state and then let it expand back to a gas. At the right temp, I don't have any idea what it is, the gas vaporizing will be O2. You just collect the gas at the right temp. and bottle it.

tdkkart
04-13-2012, 07:02 PM
I have to assume it is a portable process now as some elderly people that are on o2 now have "oxygen machines" at home rather than using bottles.
Unfortunately I know noting about the machine in question other than it's about the size of a dehumidifier and it will put out some amount of medical oxygen at low volumes.
(I work an ambuance, so I don't typically have time to get the details of household furniture and equipmemnt while I'm there.)

Yow Ling
04-13-2012, 07:44 PM
Was simpler than I thought
http://en.wikipedia.org/wiki/Oxygen_concentrator

Cant wait to get one !

oldtiffie
04-14-2012, 11:10 PM
I think that if I needed one I'd have a battery back-up and/or a UPS as if there is a power outage there may be a problem.

kf2qd
04-14-2012, 11:28 PM
An Oxygen Concentrator uses a process that absorbs some of the nitrgen out of the air giving a higher concentration of oxygen. It is not "pure" oxygen by any standard and would not be clean enough for welding and cutting processes, which need to be purer than breathing oxygen.

Tait
04-14-2012, 11:32 PM
[kf2qd and I posted about the same time, so the first paragraph is redundant to his post] This may be of limited utility, depending on what you want it for. If it's because you need to breathe a higher concentration of oxygen, a concentrator may be very helpful. It will not be pure enough or pressurized for, say, oxy-acetylene use.

@oldtiffie: Rather than a battery backup/UPS/etc, many people just keep oxygen tanks around to use if the concentrator is unavailable.

oldtiffie
04-14-2012, 11:48 PM
In the retirement village next to us (we live outside and adjacent to it) they had a major transformer or main distribution box "blow up" and it was likely to be out for a week and "took out" half the 50-unit village.

The owner asked us if we could use our power to power both an oxygenator and (I think) a defibrillator in one of the units near us. We supplied a UPS as well and all went well as the owner shouted my wife and I to a very good dinner out.

Some of the tenants elected to stay on and use LPG heating and/or to eat/shower with others whose power was on, others had caravans with gen-sets brought in and others went off to stay with relatives. It was all a very smooth operation really and a very good community effort all round. It was a talking point in the village and the town for quite a while after.

As the power was supplied from my shop and to make sure I didn't "blow a fuze", I stayed out of the shop until it was all over - about a week.

oldtiffie
04-14-2012, 11:51 PM
On a related topic.

Are people who are on an oxygen bottle (for emphasema etc) allowed to drive motor vehicles? I can't recall seeing one and most I've seen are in wheel-chairs and need Carers and most certainly don't look as if they could or should be driving.

Tait
04-15-2012, 12:24 AM
Normal sized bottles of oxygen, last on the several hours to a couple of days at the flow rates concentrators provide. I can see why a week long interruption would be a problem!

I agree there are a lot of folk on oxygen who maybe should be driving! In California, oxygen therapy can be a factor in reviewing medical qualifications to drive (link (http://www.dmv.ca.gov/dl/driversafety/pm_guidelines.htm)). If I recall correctly, oxygen therapy disqualifies for commercial driving.

macona
04-15-2012, 12:48 AM
You Ling provided a good link to how they work. They also use the same process to nitrogen purification.

The used oxygen concentrators are popular with glass blowers. They will take several in parallel and get enough flow rate to run most torches without having to buy O2 in bottles. It not pure like a bottle but it is good enough for glass.

madmec
04-15-2012, 01:47 AM
It is not "pure" oxygen by any standard and would not be clean enough for welding and cutting processes, which need to be purer than breathing oxygen.
Definitly wrong.

Breathing Oxygen ist around 99,996%, technically used Oxygen around 99,6%...

And Oxygen from good Oxygen generators ist used at least for cutting purposes- but the main problem in that application ist the compressor to increase the pressure to feed the torch.

(Oxy + Oil = BOOM!)

Thomas

Evan
04-15-2012, 02:27 AM
The vast majority of industrial oxygen and breathing oxygen is made by vacuum distillation. That means refrigerating air until it liquefies and letting it warm slowly. The primary constituents (oxy, nitrogen and argon) then boil off at various temperatures and are collected accordingly. Argon is a "waste product" of the process and is only collected when there is storage capacity available. Most is just vented back to the atmosphere.

There is no particular reason for a strict purity requirement for breathing oxygen. Anything significantly above regular air will do the job. All that matters is that it doesn't contain oil and related fumes. That is hardly likely except for silicone related products. The higher the purity the longer a bottle will last. It is diluted when breathed so that you aren't breathing pure oxygen.

philbur
04-15-2012, 06:16 AM
A more recent, last 30 years, method of "on site" seperating oxygen and nitrogen from air is to use a permeable membrane that lets one gas pass through but not the other. Industrial sized units are use in my business to generate large volumes of nitrogen, used for inerting hydrocarbon processing plant and pipelines.

Phil:)

vpt
04-15-2012, 10:08 AM
Very good info from everyone! I am aware of the oxygen concentrators since my grandmother was on one for quite some time. I wasn't sure how concentrated the oxygen was coming out of the machine though compared to atmosphere.

I am interested in the process for our fish bait. Renting and filling bottles is cheap, sure. But if it is economical I would like to pursue a concentrator or the like. There are years we go threw around 50 bottle fills.

What I am most interested to find out though is if the oxygen level that a concentrator puts out would be enough for the fish. Thats something I really don't know and can't mathematically figure out, when it comes to live things "stuff" just has to be tried in order to get a result.

Most people think just pumping air into the water is good enough and it is for like 10 fish swimming around. Millions of fish need much better oxygenation. Just pumping air into the water does two things, yes it does put small amount of oxygen back into the water but it also heats the water because of the heat in the pump which defeats the pros of the air being pumped into the water. Even running the compressed air threw a cooler doesn't help much because you are still pumping "just air" which never seems to raise the oxygen level much in the water.

There are times we will go threw a (forget the bottle sizes) 4-5'x10-12" bottle in 3 hours.

kf2qd
04-15-2012, 11:25 AM
Definitly wrong.

Breathing Oxygen ist around 99,996%, technically used Oxygen around 99,6%...

And Oxygen from good Oxygen generators ist used at least for cutting purposes- but the main problem in that application ist the compressor to increase the pressure to feed the torch.

(Oxy + Oil = BOOM!)

Thomas

Actually - Breathing oxygen can contain more of the other gases that are in air. Industrial Oxygen must be more pure in order to react properly in the cutting process. Most places the Breathing Oxygen and Industrial oxygen come from the same plant because it is convenient. Breathing Oxygen requires more paperwork....

You can easily breath a gas that contains a percentage of nitrogen, but you cannot cut steel with it.

MichaelP
04-15-2012, 02:40 PM
I am interested in the process for our fish bait. Renting and filling bottles is cheap, sure. But if it is economical I would like to pursue a concentrator or the like. There are years we go threw around 50 bottle fills.
.
Nobody uses oxygen to aerate fish containers or ponds. There are two reasons for it. First, adding oxygen to water is not the only reason for aeration. You need to remove CO2 too along with other gases. Secondly, solubility of oxygen in water is quite low. Using purified oxygen for aeration would be very wasteful and not much more efficient than using air.

You may provide adequate aeration by several methods. All of them work on one principal: creation of water surface disturbance/mixing of water layers. Gasses are exchanged at the water/atmosphere boundary, and all you need to provide is a larger interface and constant exchange of water layers where aerated water is replaced by unprocessed one. You can use compressed air or simply mix water by any mechanical means (filters, water pumps, fountains, etc.). In some situations (such as yours) you just do it on a larger scale (much more than a single airstone or pump).

The aeration provides gas exchange so that the concentrations of gases in water come into equillibrium with their concentrations in atmosphere. Naturally, it doesn't mean that the concentrations of a particular gas will be the same as in atmosphere, but it will be equillibrated based on its solubility under given condition such as water content (dissolved salts, organic pollution, etc.), water temperature and atmospheric pressure. Aeration may increase or decrease concentrations of dissolved gasses in water depending on their initial concentrations. For example, very intensive and massive photosynthesis in calm ponds may bring water oxygen concentration above equillibrium (oversaturate water with O2). Aeration of this pond will then DECREASE its content to the saturation value. At the same time, when oxygen is low and CO2 is high due to metabolic processes, aeration will RAISE oxygen content and LOWER CO2 until they come to the balanced value. And that's all you need in addition to maintaining a proper water temperature for the particular species you keep. The lower the temperature, the more oxygen can be dissolved there.

You mention that you don't really see higher oxygen values when you use oxygen for aeration. It doesn't matter what you use, the highest figure you'll be able to achieve is the equillibrium value for given conditions. For example, for a distilled water at 65F and 1 atm, the saturation value for dissolved oxygen will be about 9.4 mg/l.

The temperature part of it is the main challenge, really. It's easy when you keep tropical species and need to heat water. Cooling water for temperate water fish is much more expensive, and you need to find the most economical way to do it. It may be a constant water exchange using cool well water or it may be use of a water cooler. In your particular situation constant water exchange can be preferable not only because it will cool the tanks (or ponds), but also because you'll prevent accumulation of poisonous metabolites such as ammonia and many others that will add up very quickly in such crowded conditions. Biological filtration will help too, but water exchange is much more efficient and effective.

vpt
04-15-2012, 03:03 PM
I may have worded a part wrong. I meant that when we use an air pump to pump normal outside air into the water it does not raise the oxygen level and just increases water temp which has to stay below 50f. Oxygen out of a bottle not only is cool and doesn't heat the water but puts way more oxygen back into depleted water and does it fast. Put 10# of bait and 5# water in a 20# bag and the bait will die within minutes. Put the same amount of water and bait in the bag but then pump oxygen down into the water and fill the little area left in the bag with oxygen from the bottle and the bait will live for 2 hours.

Constant water exchange is not possible on a moving truck.

I am mainly looking for an alternative to the oxygen bottles we use. We already have agitators and all that, just looking at the oxygen side of the deal.

MichaelP
04-15-2012, 03:26 PM
I may have worded a part wrong. I meant that when we use an air pump to pump normal outside air into the water it does not raise the oxygen level and just increases water temp which has to stay below 50f. Oxygen out of a bottle not only is cool and doesn't heat the water but puts way more oxygen back into depleted water and does it fast. Put 10# of bait and 5# water in a 20# bag and the bait will die within minutes. Put the same amount of water and bait in the bag but then pump oxygen down into the water and fill the little area left in the bag with oxygen from the bottle and the bait will live for 2 hours.

Constant water exchange is not possible on a moving truck.

I am mainly looking for an alternative to the oxygen bottles we use. We already have agitators and all that, just looking at the oxygen side of the deal.
Moving truck with a closed cistern is a bit different story. :) I'd still try compressed bottled air (if it's available and less expensive), but I wouldn't be surprised if O2 will be noticably more effective in a closed space in terms of resaturation speed. In fact, I'd expect it.In this case you're stuck with bottled oxygen. A regular oxygen concentrator won't provide sufficient pressure or volume for your task.

P.S. I transported and shipped aquarium fish quite extensively in the past. I packed them into bags with about 1/5 of water and the rest- air. Population density was higher than in your case. For a 2-4-day journey it was sufficient. For longer shipment times I used oxygen to inflate the bags. But, fortunately, I dealt with tropical fish, so they were not as demanding in terms of cooling/O2 content.

philbur
04-15-2012, 04:28 PM
After you have generated your oxygen you are going to need an oil free compressor that's good for 100 - 150 barg in order to fill your bottles?

Phil:)



I am interested in the process for our fish bait. Renting and filling bottles is cheap, sure. But if it is economical I would like to pursue a concentrator or the like. There are years we go threw around 50 bottle fills.

macona
04-15-2012, 04:58 PM
Nobody uses oxygen to aerate fish containers or ponds. There are two reasons for it.

Not entirely true. I have seen trucks delivering live fish that use o2 during shipment.

MichaelP
04-15-2012, 06:14 PM
Not entirely true. I have seen trucks delivering live fish that use o2 during shipment.
I wasn't talking about cisterns, but rather about ponds, tanks and other open containers where you keep fish (vs. transport it). See my post #19 above.

vpt
04-15-2012, 07:27 PM
Moving truck with a closed cistern is a bit different story. :) I'd still try compressed bottled air (if it's available and less expensive), but I wouldn't be surprised if O2 will be noticably more effective in a closed space in terms of resaturation speed. In fact, I'd expect it.In this case you're stuck with bottled oxygen. A regular oxygen concentrator won't provide sufficient pressure or volume for your task.

P.S. I transported and shipped aquarium fish quite extensively in the past. I packed them into bags with about 1/5 of water and the rest- air. Population density was higher than in your case. For a 2-4-day journey it was sufficient. For longer shipment times I used oxygen to inflate the bags. But, fortunately, I dealt with tropical fish, so they were not as demanding in terms of cooling/O2 content.




After you have generated your oxygen you are going to need an oil free compressor that's good for 100 - 150 barg in order to fill your bottles?

Phil:)



Thats another thing I was thinking I may be able to get rid of, the bottle. I was hoping the condensing unit itself could be built into the truck somewhere and only needs to output 10psi, not allot of cfm (or whatever unit is used), much less than a torch uses and be plumbed strait to the bait tank.

MichaelP
04-15-2012, 10:44 PM
Thats another thing I was thinking I may be able to get rid of, the bottle. I was hoping the condensing unit itself could be built into the truck somewhere and only needs to output 10psi, not allot of cfm (or whatever unit is used), much less than a torch uses and be plumbed strait to the bait tank.
You can find higher end concentrators with 10-20 psi output and up to about 0.7 CFM (20 liters per minute). Regular concentrators are closer to 8-10 psi up to about 0.15-0.3 CFH (5-10 liters per minute). Doesn't sound like a sufficient flow for your needs, does it?

macona
04-15-2012, 11:33 PM
Thats another thing I was thinking I may be able to get rid of, the bottle. I was hoping the condensing unit itself could be built into the truck somewhere and only needs to output 10psi, not allot of cfm (or whatever unit is used), much less than a torch uses and be plumbed strait to the bait tank.

You are still going to need 120v for the unit's controls. It has two cartridges, one regenerates while the other is working. There are controls to handle this that will need 120v power.

Jaakko Fagerlund
04-16-2012, 04:08 AM
You are still going to need 120v for the unit's controls. It has two cartridges, one regenerates while the other is working. There are controls to handle this that will need 120v power.
Use either an inverter or change the parts to operate on 12 or 24 VDC (whatever the car has).

macona
04-16-2012, 04:57 AM
Most of the ones i have seen use a Thomas wob-l piston compressors like this: http://www.gd-thomas.com/productlist.aspx?id=9858&tp=p In fact, thats the one I pulled out of one.

Its going to take some decent current to run one, I would guess a 1kw true sine. Maybe a bit more.

vpt
04-16-2012, 08:09 AM
You can find higher end concentrators with 10-20 psi output and up to about 0.7 CFM (20 liters per minute). Regular concentrators are closer to 8-10 psi up to about 0.15-0.3 CFH (5-10 liters per minute). Doesn't sound like a sufficient flow for your needs, does it?

.7cfm is possibly enough, maybe more than enough. But I am assuming this is getting to be a fairly big unit as well?




You are still going to need 120v for the unit's controls. It has two cartridges, one regenerates while the other is working. There are controls to handle this that will need 120v power.


I was thinking power inverter possibly. Haven't got to this part yet, still trying to figure out if they put out enough oxygen and flow for our needs.

vpt
04-16-2012, 08:11 AM
Most of the ones i have seen use a Thomas wob-l piston compressors like this: http://www.gd-thomas.com/productlist.aspx?id=9858&tp=p In fact, thats the one I pulled out of one.

Its going to take some decent current to run one, I would guess a 1kw true sine. Maybe a bit more.


Do you think a weed eater motor could run a car alternator? :D

MichaelP
04-16-2012, 09:29 AM
Andy, you may speak to these guys: http://www.unlimitedoxygen.com/services.html

Take a look at the Hurricane and Hurricane Combo machines advertised there.

Here is another site with Psyclone 1 machine: http://carlislemachine.com/webcatalog/oxygen_concentrators.pdf

P.S. I'm trying to count how many cylinder refills you could buy for the amount of money you'd spend on those machines. :)

Evan
04-16-2012, 02:53 PM
P.S. I'm trying to count how many cylinder refills you could buy for the amount of money you'd spend on those machines.

Don't forget to also count the use of the free capital that wouldn't be spent all at once. That is something that most people fail to take into account when comparing a one time large immediate expenditure with a long time deferred small multiple expenditure. The proper way to count that capital is to use the largest gain available to you using that capital. For instance, paying down a credit card.

Black_Moons
04-16-2012, 07:25 PM
Don't forget to also count the use of the free capital that wouldn't be spent all at once. That is something that most people fail to take into account when comparing a one time large immediate expenditure with a long time deferred small multiple expenditure. The proper way to count that capital is to use the largest gain available to you using that capital. For instance, paying down a credit card.

I learned that lesson the hard way in some 'stock trader' video game I played as a kid.

The objective of stage one was to pay off a million dollar debt.
I obtained that amount of money and paid it off with months to go on the 1st stage....

And then did not have enough money left over to effectively make money via trading and completely lost stage 2.

Black_Moons
04-16-2012, 07:32 PM
Andy, you may speak to these guys: http://www.unlimitedoxygen.com/services.html

Take a look at the Hurricane and Hurricane Combo machines advertised there.

Here is another site with Psyclone 1 machine: http://carlislemachine.com/webcatalog/oxygen_concentrators.pdf

P.S. I'm trying to count how many cylinder refills you could buy for the amount of money you'd spend on those machines. :)

If you do plan on buying one, Might I recommend checking craigslist for a used one?

I have heard there is somewhat of a 'scam' going on with them, in that insurance companies refuse to 'buy' them for patients, but will rent them instead, at many times the end cost of buying them. Anyway the end result is some rental company ends up with hundreds of used units that are either expired or just not allowed to be reused for someone else when the patient dies. *shrugs* Not sure exactly, but the point is they recondition them for 'hobby' use and sell for a tiny fraction of new costs. Its mainly jewelers who run a small oxygen/fuel torch off them, So I have heard..


As far as 'sending fish home' I have indeed seen an oxygen tank at the local fish store, they pump the bag they sell the fish in with pure oxygen, Likely because theres no air pump in a plastic bag so pure oxygen = No need for active water/air flow. They do however just use normal air pumps for all there ponds.


After you have generated your oxygen you are going to need an oil free compressor that's good for 100 - 150 barg in order to fill your bottles?
Phil:)

I wonder if just a standard 8~10 bar compressor would be enough, given say 20 or 40 gallon tank? Much cheaper to obtain, just not as compact, but it sounds like the OP can use something less compact then a standard oxygen bottle. Not sure its safe to put pure oxygen in a tank designed for air however.. Might be leftover oils?

vpt
04-16-2012, 08:07 PM
Andy, you may speak to these guys: http://www.unlimitedoxygen.com/services.html

Take a look at the Hurricane and Hurricane Combo machines advertised there.

Here is another site with Psyclone 1 machine: http://carlislemachine.com/webcatalog/oxygen_concentrators.pdf

P.S. I'm trying to count how many cylinder refills you could buy for the amount of money you'd spend on those machines. :)


Great links! Prices actually don't sound bad. Interesting stuff!

http://www.unlimitedoxygen.com/publishImages/index~~element35.jpg

Black_Moons
04-16-2012, 08:20 PM
Great links! Prices actually don't sound bad. Interesting stuff!

http://www.unlimitedoxygen.com/publishImages/index~~element35.jpg

Picture is deceiving.
Yes, she has 2 units that appear to be hooked up to the torch.. However..
thats a 'dual' torch with 2 oxygen and 2 fuel lines with inner and outer flames.

There is also an oxygen bottle in the bottom right that appears to be hooked to the torch and 3 more units in the backround (But are not hooked up?)

So basically, those two oxygen concentrators might only be powering a tiny inner flame while the bottle provides most of the oxygen for the huge flame you see.

rowbare
04-17-2012, 10:37 AM
It is running on 3 concentrators. The caption above the image was: "Below, JOY'S Mirage on 3 M20s"

bob

Jaakko Fagerlund
04-17-2012, 12:34 PM
There is also an oxygen bottle in the bottom right
Since when it is okay to store oxygen in a green topped bottle? That would imply inert gas like nitrogen or argon.

MichaelP
04-17-2012, 01:03 PM
Since when it is okay to store oxygen in a green topped bottle? That would imply inert gas like nitrogen or argon.
Not in the US. :) Green is oxygen here.

Evan
04-17-2012, 03:21 PM
Since when it is okay to store oxygen in a green topped bottle? That would imply inert gas like nitrogen or argon.

Bottle colour is meaningless. There are no regulations or agreed conventions governing the colour of compressed gas bottles.

Jaakko Fagerlund
04-17-2012, 03:46 PM
Bottle colour is meaningless. There are no regulations or agreed conventions governing the colour of compressed gas bottles.
Maybe in some countries or internationally so, but in here the bottle color codes are regulated and thus you know exactly if the bottle contents are flammable, oxidizing, inert or compressed air etc. :)

Evan
04-17-2012, 04:04 PM
There may be local regulations but they should not be trusted. There will always be old bottles around that predated regulations. The only identification that is trustworthy is the ISO, DIN or DOT shoulder labels on the tanks. I recently had an oxygen tank (blue) converted to argon-CO2 MIG gas. They put new labels on it but didn't repaint it. BTW, it's a cheap way to get a MIG tank if you have a spare tank. It only cost $40 for a new valve body and test.

vpt
04-18-2012, 08:27 AM
Picture is deceiving.
Yes, she has 2 units that appear to be hooked up to the torch.. However..
thats a 'dual' torch with 2 oxygen and 2 fuel lines with inner and outer flames.

There is also an oxygen bottle in the bottom right that appears to be hooked to the torch and 3 more units in the backround (But are not hooked up?)

So basically, those two oxygen concentrators might only be powering a tiny inner flame while the bottle provides most of the oxygen for the huge flame you see.



I didn't even notice the bottle in the corner. Maybe the bottles name is M20. :D

Black_Moons
04-18-2012, 08:36 AM
Since when it is okay to store oxygen in a green topped bottle? That would imply inert gas like nitrogen or argon.

My very new (4 years old?) oxygen bottle is green. Bought from KMStools.

Came with a green cap on it too, if that means anything to you... Looks just like my Argon/CO2 mix bottle that I bought around the same time, except that bottle has 'Argon/CO2' written on the side in marker or some such.

macona
04-18-2012, 04:08 PM
When I worked at airgas they went through bottle handling information during new employee disorientation. The only way you trust the bottles content is with the label around the neck. Does not matter what color it is, what valve it is, what shape it is. If it does not have a sticker they may not even take it in. And if they do you get nailed for testing to find out what is inside. So never take off the label.

Evan
04-18-2012, 04:21 PM
I've had a similar course so I can fill in for my wife at her job. Among abrasives and related items she also sells industrial gases and tanks.