NITROX Membrane systems recommendations.

[SeaCaveSeeker]

The old-style membranes do require the heater; the new Nitrox Maker, low-temperature units do not. Their are many great benefits when avoiding the high-inlet temperature. Brownie's patented Nitrox Maker is the only system on the market that is directly compatible with a factory Bauer and MAKO compressor; all others exceed the 100-degrees F inlet temperature design standard. Multiple, high-end dive operators are now switching to the patented low-temperature systems and reporting great results. This operation in Mexico has been running one for over year: Zero Gravity Filling Station

 

[ediverudt]

The old-style membranes do require the heater; the new Nitrox Maker, low-temperature units do not. Their are many great benefits when avoiding the high-inlet temperature. Brownie's patented Nitrox Maker is the only system on the market that is directly compatible with a factory Bauer and MAKO compressor; all others exceed the 100-degrees F inlet temperature design standard. Multiple, high-end dive operators are now switching to the patented low-temperature systems and reporting great results. This operation in Mexico has been running one for over year: Zero Gravity Filling Station

thank you for the reply that is really help full information. I greatly appreciate it.

 

[Peter_C]

Seems like it would be more cost effective to mount a high pressure bank system in the trailer? Unless this is a multiple day excursion? How many times do you need to fill those 10 AL80's? Heck buying 80 more tanks sounds cheaper.

 

[iain/hsm]

Not sure what the patent bit is but in Europe we have been using standard off the shelf $4000 heat less membranes for years.
You can buy them for nitrox or nitrogen. They are the same you guys use, made in Holland.

The only “cost” apart from mechanical control is you require more low pressure drive air.

For 17 acfm HP comp for 36% you need a 41 acfm low pressure drive at 100 psig

For the same size 17 cfm HP pump running 32% the LP air is 29 acfm also at 100 psig

Now the trick is the allowance used you put on ambient air temperature, LP drive air temp and the reference
back to 20C 68F and 1013 mbar ATA reference

With a LP air heater you can lower the drive air requirement. Six of one half a dozen for the other if you ask me
but the IR 2545 175psi 35 acfm will probably cack the membrane up with oil first. or you overheat the Bauer.

Most folk buying the ready built nitrox membranes units are either rich or clueless hence the high price and poor specification.

But the membrane itself is a simple tube, Just three important points.

1. Air purity is the key.
2. Particulate or oil are the killers,
3. and filters by there very nature fail.

Most break down before the first year is out and always require a new membrane,
it doesn’t take much to jam solid a membrane that is designed to split air molecules in two.

Look at the guarantee you get for the first year (Does not included the membrane) , not the claim made for 30 years long life

Consider this when using an oil lubricated compressor.
One teaspoon of oil is enough to cover a swimming pool.
One drop enough to kill your membrane. Your call.

However expensive the build we see innocent users unqualified operators and care less management in hot climate areas
filling punters on the Red Sea “ferry bus”

Gas quality is another matter as most membranes are gas concentrators so C02 is normally over twice
the allowable maximum for the allowable breathing air quality.

But as most punters on holiday don’t have analysis no one knows.

Oil free oil less LP air drive units are limited in pressure hence the 100psi and flow and the 30 acfm flow example
I used but if you are OK with trusting your investment to a bucket of oil and filter mop then fill your boots
any LP air compressor could be considered.

Oil flooded rotary screws are generally better than reciprocating piston units due to the lower oil carry over but again in hot climates
a water float filter could be considered as it is easier to filter water than oil.

On the high pressure side IMHO I would want the HP compressor tested to at least 60% before allowing 40% to run through it,
but by the growing number of burnt out HP blocks stand testimony to a similar working pressure/test pressure ratio
difference as in HP cylinders (tanks) should be useful with nitrox.

Failing that a simple electronic automatic blender for use with rented bottled oxygen can be bought for $4000 and
you can run the power from a simple $500 Honda 5HP generator.

The gas is not concentrated with C02 and mixing on the fly is just a turn of the dial.
You don’t need the LP compressor just a few rental oxygen cylinders
although you still will oxidize away the lubrication properties of the oil in your Bauer

So as you gain more experience with nitrox by membrane production and eventually revert your now worn oil lubed Bauer
back to the air compressor it was designed originally for your loss in investment is less.

The "deal" with nitrox is simple. The interest in you from suppliers simpler.

If your rich they are interested if not, no bother. LOL Iain Middlebrook

 

[CraigAClark]

The old-style membranes do require the heater; the new Nitrox Maker, low-temperature units do not. Their are many great benefits when avoiding the high-inlet temperature. Brownie's patented Nitrox Maker is the only system on the market that is directly compatible with a factory Bauer and MAKO compressor; all others exceed the 100-degrees F inlet temperature design standard. Multiple, high-end dive operators are now switching to the patented low-temperature systems and reporting great results. This operation in Mexico has been running one for over year: Zero Gravity Filling Station

Care to show us in writing from either company that they are directly compatible? Funny that you don't mention the problems that have occured with air cooled units. Inlet temperature refers to the temperature entering the filtration tower, which an air cooled compressor will exceed everytime in a tropical climate, except when the machine has been modified for water cooling with chilled water. If you are refering to the "INTAKE" temperature, which is going to vary with the ambient temperature (basic physics), then how are you maintaining that 100 F? Got any of those reports from those "Multiple High End" dive operators to back up that they are actually switching?

Craig

BTW, Hi Robert.

 

[Wookie]

Been on the phone with Mako a bit today, as I have oil problems in a 5406 nitrox machine. It was pretty clearly stated to me that Mako does not have any machines rated for nitrox unless you get into the industrial line of air compressors..... But I already knew that.

 

[ediverudt]

Not sure what the patent bit is but in Europe we have been using standard off the shelf $4000 heat less membranes for years.
You can buy them for nitrox or nitrogen. They are the same you guys use, made in Holland.

The only “cost” apart from mechanical control is you require more low pressure drive air.

For 17 acfm HP comp for 36% you need a 41 acfm low pressure drive at 100 psig

For the same size 17 cfm HP pump running 32% the LP air is 29 acfm also at 100 psig

Now the trick is the allowance used you put on ambient air temperature, LP drive air temp and the reference
back to 20C 68F and 1013 mbar ATA reference

With a LP air heater you can lower the drive air requirement. Six of one half a dozen for the other if you ask me
but the IR 2545 175psi 35 acfm will probably cack the membrane up with oil first. or you overheat the Bauer.

Most folk buying the ready built nitrox membranes units are either rich or clueless hence the high price and poor specification.

But the membrane itself is a simple tube, Just three important points.

1. Air purity is the key.
2. Particulate or oil are the killers,
3. and filters by there very nature fail.

Most break down before the first year is out and always require a new membrane,
it doesn’t take much to jam solid a membrane that is designed to split air molecules in two.

Look at the guarantee you get for the first year (Does not included the membrane) , not the claim made for 30 years long life

Consider this when using an oil lubricated compressor.
One teaspoon of oil is enough to cover a swimming pool.
One drop enough to kill your membrane. Your call.

However expensive the build we see innocent users unqualified operators and care less management in hot climate areas
filling punters on the Red Sea “ferry bus”

Gas quality is another matter as most membranes are gas concentrators so C02 is normally over twice
the allowable maximum for the allowable breathing air quality.

But as most punters on holiday don’t have analysis no one knows.

Oil free oil less LP air drive units are limited in pressure hence the 100psi and flow and the 30 acfm flow example
I used but if you are OK with trusting your investment to a bucket of oil and filter mop then fill your boots
any LP air compressor could be considered.

Oil flooded rotary screws are generally better than reciprocating piston units due to the lower oil carry over but again in hot climates
a water float filter could be considered as it is easier to filter water than oil.

On the high pressure side IMHO I would want the HP compressor tested to at least 60% before allowing 40% to run through it,
but by the growing number of burnt out HP blocks stand testimony to a similar working pressure/test pressure ratio
difference as in HP cylinders (tanks) should be useful with nitrox.

Failing that a simple electronic automatic blender for use with rented bottled oxygen can be bought for $4000 and
you can run the power from a simple $500 Honda 5HP generator.

The gas is not concentrated with C02 and mixing on the fly is just a turn of the dial.
You don’t need the LP compressor just a few rental oxygen cylinders
although you still will oxidize away the lubrication properties of the oil in your Bauer

So as you gain more experience with nitrox by membrane production and eventually revert your now worn oil lubed Bauer
back to the air compressor it was designed originally for your loss in investment is less.

The "deal" with nitrox is simple. The interest in you from suppliers simpler.

If your rich they are interested if not, no bother. LOL Iain Middlebrook

For the sake of this forum and for further investigation would you mind mentioning any of the sources in Holland that yo know of for the no heater nitrox membrane systems. I am interested for some expedition related altitude diving where we cant possibly refill o2 bottles. I am also interested in general because I have not found a reliable source of O2 nearby and will be doing allot of altitude diving.

 

[Scuba Duck]

Thought I'd throw in my two cents.

For membrane systems that use high pressure feed air, the heater is a must. Otherwise the very cold air going into the membrane from the adiabatic expansion from high pressure to low pressure will freeze/embrittle the little tubes in the membrane leading to rupture. Had a client here that did that a couple times. Expensive mistake as you get to purahse a new membrane.

For low pressure feed systems, the heater is not required.

The heater changes the characteristics of the membrane, at colder temperatures, the membrane produces a lower volume of higher enrichment permeate. As the membrane warms up, for the same input air pressure, the premeate migrates through the walls of the little tubes faster and you get a higher volume of permeate but at a lower oxygen concentration. If you are trying to squeeze the maximum out of a given membrane, the heater helps do this. If your membrane is a little oversized for the application, then you don't need the heater, and can in fact use a smaller low pressure air compressor. Having more membrane (interior tube surface) effectively increases the dwell time in the membrane and results in more separation of gases. A lot of oxygen actually goes out the nitrogen vent.