Nitrox Stick Manufacturers

[Doc Harry]

You need to monitor your setup at all times when filling nitrox.

Yup.

I have to stand there and watch the gauges the entire time.
I also have manual drains that require intervention every 10 minutes.

I have a big filter stack downstream of the compressor, and my output at the whips is oxygen clean air. I can pump my tanks full of EAN32 or add some 100% O2 to my deco cylinders and top them off with the compressor to get my deo mixes.

It's beautiful.

 

[BoltSnap]

Whoa, time out dude - you need to do some more reading before you get into this compressor stuff - there are some dangers which you need to understand.

Tanks need to be O2 cleaned to accept nitrox as well, according my SDI certification to mix and make nitrox; all new standards also agree with this.

It can get dicey if your clients use their tanks on any old compressor after they've been O2 cleaned, because the tank owner takes the liability to make sure they only fill off compressors that have been certed as producing O2 compatible air, thus not dirtying the tank. In the US, it would seem most LDS compressors are pretty well maintained and monitored such that we rarily hear of anyone exploding a dirty tank with nitrox - that said "hear" would probably be the key word.

Molecular sieve pulls water out of your air to make standards - if you are filling steel tanks this is critical to keep them from rusting, or from regulators freezing up and free flowing (probably not an issue in your area, just guessing). Carbon is used to pull out hydrocarbons (ie oils) from the air stream - deadly if breathed at depth. Also Hopcalite is used to convert CO to CO2. Google Lawrence Factor filters and read up. This is a critically important part of your compressor system and your ability to produce breathable air and not kill someone.

Read some more compressor threads in this Equipment thread section of SB and you'll get a good understanding of what you don't understand and need to go research.

Alternatively pay one of the big manufacturers (like Bauer) to come and put your system in and teach you how to use it.

I am confused with what you are saying here. What is your point? I don't get you at all. Tanks and all equipment have to be "O2" clean if they are going to be in contact with 100% O2 even if the final mix is <40% O2. Now, what is your point again??

What exactly you think I don't understand but YOU understand?

 

[swamp diver]

Swamp diver,

I wasn't looking at their most expensive hardware. I am looking at their portable air compressors to use with a Nitrox Stick

That Bauer B-Trox system looks like it would need one big suitcase full of Euro bills.

Burhan you're quite right that a suitcase of Euro is likely neeed. Not sure exactly but probably in the 18,000 range for one of the smaller ones.

I would agree that given your circumstances whereby you cannot ensure that the tanks coming to you have been properly O2 cleaned the nitrox stick is probably the way to go. Most of the severe injuries and fatalities (there was one in Florida about 5 years ago) which have happened involved tanks during the fill process which had unverifiable O2 cleaning. Just because someone purchases a sticker on the Internet saying their tank is O2 clean does not mean it is clean,...huge problem over here.

Also as you point out a tank that was initially O2 clean can become unclean when it is taken to another fill station where the air quality is suspect. We switched to a membrane system partly to reduce the risk of this problem once it became very evident by inspecting tank valve seats quarterly that a lot of oil and particulate was coming from other fill stations which claimed to be pumping oxygen compatible air.

In terms of compressor choices I am partial to Bauer but realize they are more expensive than the Coltri. I'm not sure what type of liability you have to worry about over there in Libya, but Coltri will provide documentation that their compressors can be used to pump up to 40% nitrox at 3600 psig should you require this. Bauer Europe will not unless you purchase a 12.14-OX block or larger.

I'll tell you a bit of a secret though which is Bauer USA is pairing its stock air compressors with a membrane system developed by Brownie's using a membrane and Kaeser lp compressor. There are no modifications such as stage temp monitoring nor an extra 1st/2nd stage separator like you find on the Euro Bauer nitrox compressors.
Brownie's Patented Nitrox Maker(TM) to be Featured at Bauer Compressors, Inc.'s Booth at the DEMA Dive Industry Trade Show OTCBB:BWMG

As you know from reading on here lots of people have been using air compressors to pump nitrox without incident although there are several steps you can take to mitigate the risk such as:

1. use only a high quality synthetic oil as these have a higher autoignition point and fewer flammable volatiles sitting above the oil compared with a mineral oil.
2. probably most important is to keep the compressor as cool as possible. Put a large axial blast fan on the stage heads and only pump at night when it is coolest. All the compressors are under-ventilated when in hot tropical environments and require additional cooling. Plus you'll lower your maintenance costs by doing so.
3. make sure that you only use Viton 90 o-rings for the discharge valves or any other high heat, high pressure locations.
4. consider putting the high air temp alarm on the 4th stage if you are going to have a PLC control.

Have a look at this article just to refresh your knowledge regarding the potential risks and realize that the dive industry is the only group out there advocating the 40% rule.

If you do happen to find that wheelbarrow of money you might rather purchase a new Rix oil-less compressor.

 

[BoltSnap]

I am partial to Bauer myself too but Coltri is also available. Bauer appears to have better reputation for quality around here. No one here checks anything or regulates anything. I am leaning towards the Nitrox stick with a Bauer compressor to make 40% O2 Nitrox (or less) and not worry about O2 cleaning. There will be a point where we will need to make higher % O2 fills in the future for technical divers as the market develops here but I'd worry about it in a couple of years if and when the markets needs this type of service. My concern now is to make EAN40 with the least headache and practicality and not spend a fortune.

If I consider the membrane system, I'd but the Nuvair system but I think that it is still too expensive for us here.


Would I need to change o'rings on the Bauer compressor or is it all OK the way it comes from the manufacturer? Also, is the oil supplied by Bauer OK for this type of use?

In term of cooling, I am not sure of what type of fans to use from your description. My plans are to use a big fan in the window and/or use big A/C unit.

 

[maniago]

If you do happen to find that wheelbarrow of money you might rather purchase a new Rix oil-less compressor.

No not really. Smaller Rix' -3s and -6's aren't certed for nitrox pumping - infact Rix make sure goes out of its way to make sure the buyer knows this. They have built nitrox pumpers but they are special orders. Iain Middlebrook can enlighten us if he come by here.

That said, folks do pump nitrox with a -6 Rix tho - they are monster heat pigs when doing so, eat their teflon rings and oring seals and generally suffer in performance and increased maintenance - but all their parts are available and replaceable (for a price).

After the experience of rebuilding mine, I've decided to just partial pressure fill instead....kinda like finishing a restore on a '57 Chevy PU and deciding that maybe hauling that load of stone wasn't the best reason to buy that truck....!

Now to find a Haskel

---------- Post added April 13th, 2014 at 04:19 PM ----------

I am confused with what you are saying here. What is your point? I don't get you at all. Tanks and all equipment have to be "O2" clean if they are going to be in contact with 100% O2 even if the final mix is <40% O2. Now, what is your point again??

What exactly you think I don't understand but YOU understand?

Dang! Got an ego?

Do yourself a favor, and start by reading the article that SwampDiver attached and then read the Oxyhacker book before you start trying to make nitrox. Both reads will give you an idea of what areas of knowledge you might be missing. Neither I nor anyone else here can fill in what you need to know because we don't know what you know.

OxyHackers book is the price of admission into the compressor world, IMHO. Noone should own a compressor without reading it first - the wealth of knowledge is immense. Its a light bulb in the darkness. Otherwise, you're just stumbling not knowing what to ask.

I'm not trying to be mean, because I was in your shoes 8months ago - naive about nitrox making, and compressors in general. I thought it was easy peasy - any fool can do it. But its not. Its not for fools.

I'm trying to help you before you spend a whole lot of money and possibly avoid you getting hurt in the process. You can do this stuff, but to do it safely you need to know what you are doing. Read and research.

 

[swamp diver]

I am partial to Bauer myself too but Coltri is also available. Bauer appears to have better reputation for quality around here. No one here checks anything or regulates anything. I am leaning towards the Nitrox stick with a Bauer compressor to make 40% O2 Nitrox (or less) and not worry about O2 cleaning. There will be a point where we will need to make higher % O2 fills in the future for technical divers as the market develops here but I'd worry about it in a couple of years if and when the markets needs this type of service. My concern now is to make EAN40 with the least headache and practicality and not spend a fortune.

If I consider the membrane system, I'd but the Nuvair system but I think that it is still too expensive for us here.


Would I need to change o'rings on the Bauer compressor or is it all OK the way it comes from the manufacturer? Also, is the oil supplied by Bauer OK for this type of use?

In term of cooling, I am not sure of what type of fans to use from your description. My plans are to use a big fan in the window and/or use big A/C unit.

I'm fairly sure that the o-rings which come on the discharge valves are Viton or the FKM equivalent. Just make sure if you are going to start doing your own valve jobs that you use Viton or viton equivalent if purchasing non-Bauer elastomer parts.

The new smaller Bauer blocks just are not cooled like the older K14, in fact if you can find a used low hour K14 I'd strongly recommend that over a newer IK12.14 or smaller blocks. The cooling with the K14 radial fan is much better than the new fan design. Bauer says that you can operate their compressors with synthetic oil up to 45 C but our experience with nitrox says otherwise. I would not pump when your ambient is higher than 35 C and the lower the temp the better. Even Bauer's claim of an upper pressure of 300 bar on its nitrox units is too high and Coltri's upper limit of 250 barg is more realistic with less wear and tear on the pump.

In terms of supplemental ventilation have a look at this photo below provided to me by another knowledgeable forum poster who is also located in a high heat tropical area. Any fan will do but you want it blowing across the stage heads to lower their operating temperatures. The higher the velocity the better up to about 70 km/hr or so after which there is diminishing returns. And make sure that you have at least a metre of space between any wall and the compressor's own fan. Too many compressors are jammed against the wall and one just creates a heat loop.

You'll probably find that the AC unit cannot keep up with the heat produced by the compressor or that the AC unit makes very little difference unless a huge one. I'd probably just put a large exhaust fan on the room to extract the heat. You can purchase an infra-red thermometer and adjust fans until you get the cooling correct on the stages.

Another option in your high heat location would be to consider a water-cooled compressor. There is a fellow Bob Olsen out of California who modifies Bauer compressors so that all the stage heads are water-cooled. That is the best way to keep a compressor properly cooled but I suspect it is pricey. Have a look at the NS450 water-cooled here.
http://lauderdalediver.com/dive/dive-compressors/dive-compressors/

Regarding the oil yes the Bauer oil supplied in the new compressor should be their synthetic oil.

 

[BoltSnap]

I'm fairly sure that the o-rings which come on the discharge valves are Viton or the FKM equivalent. Just make sure if you are going to start doing your own valve jobs that you use Viton or viton equivalent if purchasing non-Bauer elastomer parts.

When it is time for service, I will use spare parts sourced from the vendor/manufacturer of the equipment I bought. I am not the type that tries to cut costs by going all over the place to find o'rings from other sources because they are cheaper but not sure of their matching the equipment to be serviced. I buy from original equipment manufacturer and I don't have to worry about it. In my part of the world there are all types of fakes and counterfeit crap. Almost all auto spare parts here in Libya are counterfeit sourced from China. I am not going to play this game with my dive business.

The new smaller Bauer blocks just are not cooled like the older K14, in fact if you can find a used low hour K14 I'd strongly recommend that over a newer IK12.14 or smaller blocks. The cooling with the K14 radial fan is much better than the new fan design.

No used anything here in Libya, the diving industry as we know it in the outside world doesn't exist. I am a "pioneer" in what I am trying to do here. There are a couple of guys with their compressors in their garages here but that's it. I prefer to buy new from an authorized vendor/supplier to make sure that I am getting authorized new product.

Even Bauer's claim of an upper pressure of 300 bar on its nitrox units is too high and Coltri's upper limit of 250 barg is more realistic with less wear and tear on the pump.

I am not sure that I am following here, are you saying that I shouldn't fill the storage tanks to 300bar if the tanks and the compressor is rated to this pressure?

In terms of supplemental ventilation have a look at this photo below provided to me by another knowledgeable forum poster who is also located in a high heat tropical area. Any fan will do but you want it blowing across the stage heads to lower their operating temperatures. The higher the velocity the better up to about 70 km/hr or so after which there is diminishing returns. And make sure that you have at least a metre of space between any wall and the compressor's own fan. Too many compressors are jammed against the wall and one just creates a heat loop.

One fan like the one in the picture blow air on the compressor and another big fan on the other side of the room sucking air out from the room to the outside (need a window in the room for new air to come in). Plus make sure that the compressor is about 1 meter away from the wall in all sides.

 

[swamp diver]

I am not sure that I am following here, are you saying that I shouldn't fill the storage tanks to 300bar if the tanks and the compressor is rated to this pressure?

For air not a problem but having used a Bauer nitrox block for a couple years now you'll have problems with o-ring damage due to explosive decompression with nitrox and all the downstream heat problems that go with pumping to 300 bar.

Bauer also will tell you that you can run a synthetic oil for 2000 hours or 2 years whichever is shorter all the while running the compressors at 45 C (air). I can pretty much guarantee having sent our compressor oil out for analysis that even if pumping air that interval is too long.

All manufacturers like to stretch the truth for marketing purposes and while you might get away with intermittent use of the nitrox compressor to pump 40% to 300 bar if you are doing that on a continuous basis you are going to find that you'll be repairing the integrated seal on the first stage every few months and having issues with your final stage dischage valve o-ring. Coltri uses the same compressors for air and nitrox and they have dropped the maximum operating pressure on the nitrox compressors from 300 barg to 250 barg likely for good reason.

We change our compressor oil on the hp nitrox unit out every 250 hours as the lab data showed the oil remained in spec up to this point in time. Bauer will tell you 1000 hours but lab data suggests otherwise when pumping nitrox which oxidizes the oil much faster than air.

One fan like the one in the picture blow air on the compressor and another big fan on the other side of the room sucking air out from the room to the outside (need a window in the room for new air to come in). Plus make sure that the compressor is about 1 meter away from the wall in all sides.

Have a look at the attached photo. You want the cool air inlet down low as shown and the hot air exhaust up high as shown. You can put an exhast fan at 'D' but I'd also have an extra axial fan blowing on the stage heads if operating above 30 C.

http://www.bauer-kompressoren.de/pd...serviceunterlagen/installationshandbuch_e.pdf


Yes if you have to worry about fake parts it would be much easier to just use the OEM parts.

 

[gekodivebali]

I'm using the same blowers on my compressors in Bali. 30 deg, 70% humidity here is pretty average. I wouldn't go without these.
The Bauer distributor here also installed the oxyflow for Nitrox mixing. Funny when you consider that that Bauer Asia does not recommend pumping Nitrox.
I felt the oem p21 filters on the unit were not fit for this climate. I guess they would be even less fit for Libya...
I replaced them by a p62 ( similar to some setups by LF), added a moisture sensor, along with a block in order to be able to fill 4 tanks at once.
This adds less wear on the system, a way to monitor humidity and the efficiency of the installed molecular sieve/hopcalite/carbon cartridge (500 tanks per 150$ mini) and a greatly reduced cost on all consumables. I cannot stress how important this is when compressing breathing gas in hot/humid climates. Finding this type of setup in Libya would probably be mission impossible, but I'm guessing you'll have to import everything from Europe anyway.
This was also the reason why I asked where you would source the molecular sieve and activated carbon or at what price. Importing these from Europe would be PITA... If you do no know what these are please read instruction manuals for the mariner 320 or your model of choice before considering pumping... Else your divers would end up with as much oil in their tanks as in that of their cars!

I agree that if divers from outside bring their own tanks then pp blending is out of the question...

Wish you all the best and hope we can dive on some great sites you may find in the Libyan waters soon!

 

[BudSned]

One of the problems with making your own stick is that it won't have all the electronic safeties that the Tri-Hunter has. The Tri-Hunter will automatically cut off the oxygen flow if the percentage in the stick exceeds 39%, power loss to the control box or compressor shutdown. It continuously monitors the Oxgen content and is easily adjusted. The Tri-Hunter will also make tri-mix. You can easily convert a partial bottle of mix A to mix B by simply punching pressures, percentages and tank size into the computer and set you additional mix accordingly. It's a great system. I know it very well. They will ship them anywhere in the world. They cost about $3200 US$

Bud
A+ Compressor Services

Nice stick doc. I agree, piece of cake to make out of PVC.

I use a properly sized flow control orifice on the O2 regulator, then I never have to worry about a valve being changed. The first time I start my compressor, I generate a concentration curve based on the PSI on my O2 reg. so i know exactly what percent 02 is going through my compressor at any given time. I also put a small sleeve of 1/2 inch copper pipe on the regulator handle so that it can not be screwed in to deliver more then 38 percent or so to the compressor. I also have an O2 solenoid that shuts off flow to the stick in the event the compressor looses power. Because of these safeguards I do not sample upstream of my compressor; only downstream to tweak concentration. I have blended nitrox for several years this way. As doc said the analyzer upstream would give you an indication of improper mixing and if you have too much resistance in the stick.