using MCH6 for continues blending

[alanchang]

Does anybody recommend using a MCH6 to to continues blending? meaning using a nitrox stick. For home use only. 2fills per week max. Oil change not a problem(doing it very frequently). Blending maximum 32 nitrox

I know MCH6’s fourth stage sit in oil and dirt oil/carbon build up with seize it up very quickly and I know adding oxygen make the oil dirty a lot faster.

I know MCH6 has a smaller oil sump and it’s a small block and it’s not really good in tolerating heat and adding oxygen will make it hotter.

I have consulted with the manufacture and the manufacture approved this but recommended to limit the pressure below 3500psi and change oil more frequently which I have no problem with

Just want to know if anyone has any ideas about this and any experience. Any help are helpful.

 

[zider]

I’ve been running mine with a stick for a few months and have had no issues so far. Thanks for posting the details from Coltri. I hadn’t thought about the increased heat and impact on the oil.

 

[iain/hsm]

I have consulted with the manufacture and the manufacture approved this. Any help are helpful.

No way you will get this in writing. Just ask them again.

What percentage exactly above 40% did Coltri test to? And for how long and at what pressure?


For example a standard industrial nitrox compressor certified to 40% discharge percentage using continuous blending (entrained oxygen from a single stage regulator) would be required to run for for one hour at full pressure and temperature at between 75% to 80% oxygen concentration with zero degrading oxidation of the lubricant and no particulate contamination (kindling fire component) .

Your MCH6 will not get even close.

Running it at 40% is one thing. Testing it for 40% is quite another

You are being misled Read the label on the compressor.

My guess it will read Air Compressor (21%)

 

[alanchang]

No way you will get this in writing. Just ask them again.

What percentage exactly above 40% did Coltri test to? And for how long and at what pressure?


For example a standard industrial nitrox compressor certified to 40% discharge percentage using continuous blending (entrained oxygen from a single stage regulator) would be required to run for for one hour at full pressure and temperature at between 75% to 80% oxygen concentration with zero degrading oxidation of the lubricant and no particulate contamination (kindling fire component) .

Your MCH6 will not get even close.

Running it at 40% is one thing. Testing it for 40% is quite another

You are being misled Read the label on the compressor.

My guess it will read Air Compressor (21%)

This is written on both the compressor manual and the compressor oil. Both clearly stated “Designed to be used below 40% Nitrox”. I will shoot you a picture once I got home.

 

[Tanks A Lot]

An MCH-6 is approved for Nitrox up to 40% according to Coltri.

The compressor can also be used to obtain other non-breathable gases for industrial use such as:
- Nitrogen
- Helium
- Nitrox 40% max O2
Any other use is inappropriate: the manufacturer cannot be held liable for any personal injury or damage to objects / the machine itself caused by improper use.

Bauer is much more restrictive in writing, but talk to any engineer at Bauer and they tell you the same off the record. Their Nitrox compressors are mostly the same blocks with extra temperature sensors to shut down the machine in case of overheating. I guess they are just covering their bases.

You will have absolutely no problems pumping Nitrox up to 40% with it whatsoever, I have seen a few doing this for years and as stated above, they are designed to do so. It is the first time I heard that Coltri suggests more frequent oil changes when pumping Nitrox.

 

[rob.mwpropane]

No way you will get this in writing. Just ask them again.

What percentage exactly above 40% did Coltri test to? And for how long and at what pressure?


For example a standard industrial nitrox compressor certified to 40% discharge percentage using continuous blending (entrained oxygen from a single stage regulator) would be required to run for for one hour at full pressure and temperature at between 75% to 80% oxygen concentration with zero degrading oxidation of the lubricant and no particulate contamination (kindling fire component) .

Your MCH6 will not get even close.

Running it at 40% is one thing. Testing it for 40% is quite another

You are being misled Read the label on the compressor.

My guess it will read Air Compressor (21%)

Is there anything that would be required of a Rix if pumping nitrox through it? (Obviously under 50%). Need to cool down more often or ???

 

[alanchang]

Is there anything that would be required of a Rix if pumping nitrox through it? (Obviously under 50%). Need to cool down more often or ???

Never seen a Rix before. Don’t know why people are using it and where it is popular. Coltri and nuvair are the only two stated by the manufacture that allows Nitrox

 

[rob.mwpropane]

Never seen a Rix before. Don’t know why people are using it and where it is popular. Coltri and nuvair are the only two stated by the manufacture that allows Nitrox

They can state for nitrox use all day long but do you really think people haven't used other compressors to blend nitrox for decades now? I mean, there's not a huge difference between 21% vs 32%.

A Rix is pretty neat (I'm sure there are others), but it uses teflon rings instead of oil, so much less a chance of any contaminates. I don't think I'd use it in a commercial setting as it needs to be rebuilt more often, but my little Rix works fine for me.

They're pretty popular with the government for which they were designed I suppose.

edit: @alanchang I just reread my post, I didn't mean for that to come off offensive if it did.

 

[iain/hsm]

The compressor can also be used to obtain other non-breathable gases for industrial use such as:
- Nitrogen
- Helium
- Nitrox 40% max O2
Any other use is inappropriate: the manufacturer cannot be held liable for any personal injury or damage to objects / the machine itself caused by improper use.

Please read again and carefully your statement above from the manufacturer Coltri for the MCH 6 and ask yourself these three simple questions.

1. What part of non breathable gases do you not fully understand.
2. What part of for industrial use such as is not fully understood.
3. What part of any other use is inappropriate is again not fully understood

 

[iain/hsm]

Coltri and nuvair are the only two stated by the manufacture that allows Nitrox

Sadly your wrong on the both counts

1. With Coltri clearly they don't approve as per as they declared above.

2. And Nuvair are not the manufacturer. They IMHO are just telling you the bullshot you want to hear to make a sale. So Ask Nuvair themselves what percentage did they test the MCH 6 compressor to above this 40% number to ensure safety

After that we can then get into the real reasons why they all want you to change out the oil much sooner than for breathing air.