Need a little help with my nitrox stick

[KD8NPB]

Check for air leaks all the way up to the 1st stage piston. Slip fittings may leak...Use some electrical tape to snug it up and act as a gasket.

How are you handling tank sampling? Are you utilizing a regulator with a flowmeter to ensure a constant flow in to your analyze while tank sampling?

 

[NAM001]

As far as not rinning ean through the filters. The filters remove hydrocarbons/oil and is held in the decicant ect.

That analyzer comes with a thermistor and pretty much stays in the nitrox stick...


I should get the desired reading using the hand held analyzer...

---------- Post added December 7th, 2013 at 12:28 PM ----------

im using a medical LPM regulator that goes to 15 lpm. That does not seem to be enough for the stick/compressor setup. The stick is the Oxygen hacker's plan and the compressor is a 20.8 cfm.

I can open the oxygen flow valve enough to get up to 38% reading at the sensor....

could my filtering have anything to do with it?

my filters (Lawrence factor) say not to run enriched air through them... wonder why?

 

[Topbodz]

Check for air leaks all the way up to the 1st stage piston. Slip fittings may leak...Use some electrical tape to snug it up and act as a gasket.

How are you handling tank sampling? Are you utilizing a regulator with a flowmeter to ensure a constant flow in to your analyze while tank sampling?

NO, just putting the analyzer against the valve face, with the valve cracked open....


the analyzer is a Palm o2

 

[Peter_C]

The stick is the Oxygen hacker's plan and the compressor is a 20.8 cfm.

That is a BIG compressor. Your stick is probably too small, as it should be around 4-6 inches in diameter. I would worry about it pulling a vacuum on the stick. Rig up a mano meter and measure it after the stick. What size is your stick and your inlet tubing?

So what is the difference in readings between the O2 analyzer in the stick with the compressor running and the compressor shut off? That is a very telling number. Post those up please.

 

[Topbodz]

That is a BIG compressor. Your stick is probably too small, as it should be around 4-6 inches in diameter. I would worry about it pulling a vacuum on the stick. Rig up a mano meter and measure it after the stick. What size is your stick and your inlet tubing?

So what is the difference in readings between the O2 analyzer in the stick with the compressor running and the compressor shut off? That is a very telling number. Post those up please.

The stick is the 2 inch PVC as described in the oxy hacker's plan.

inlet tube is 1" ID

I think 6" would give me way too much air, and I would have a lean mixture even with the oxy full blast

im going to look for an LPM reg that goes higher than 15 LPM...... then maybe I could try 4" stick or so....


with the compressor off and calibrated at 20.9, I get around 18% when I star it.

Nuvair told me to calibrated it with the compressor running (oxy off of course) then I get around 23.8 or so when I turn the comp off.


today I had the stick set at 32.5% and was getting around 31.9 at the end of the whip.... got interrupted by someone and the compressor reached its shut off point...

will experiment again on Monday

 

[Peter_C]

with the compressor off and calibrated at 20.9, I get around 18% when I star it.
~then I get around 23.8 or so when I turn the comp off.

That is too much of a restriction and will damage the compressor over time. That is the same size stick I have on my 10cfm compressor and I get a little bit of vacuum even, and have considered building a new stick or punching a few holes into my baffles. Might be easier for you to just build a larger wiffle ball stick.

How large is your inlet tubing?

Edit: These past threads might help you out.
http://www.scubaboard.com/forums/co...-blending-systems/403418-nitrox-blending.html
http://www.scubaboard.com/forums/co...systems/423065-new-nitrox-stick-question.html
http://www.scubaboard.com/forums/co...ending-systems/403618-nitrox-stick-plans.html

Hope that helps

 

[BRT]

I use a 15 lpm medical flow control on my 1.9 cfm compressor. To get 32% I run it at about 7.5 lpm, which is close to what it calculates to. Your 20 cfm compressor would need 5 of those regulators to get 32%. The medical regulators I have seen are rated at 50 psi and if you raise or lower that pressure the flow is way off the reading on the regulator. You need a big enough stick to get almost no vacuum.

 

[NAM001]

tHERE IS NO SUCH THING AS TOO BIG OF STICK IN REGARDS TO (sorry) compressor protection. You can use a 4 foot culvert for the intake and the compressor will not take any more air than with a 6" input. However too small is another matter. the smaller the intake pipe the quicker you can see the results of a O2 injection change.

Now the other thing with the calibration. I think you are mixing apples and oranges.

Let me understand some things before i continue

You are using a nitrogen removal system, the nuvair bla bla bla. the nuvair is putting out say 32% from it.
you are inputting this into the compressor via a stick.

If i am correct so far, i will say that you problem is that you are leaking air into the compressor. Your nuvair (IE) is putting out 18 cuft of 32% and you are piping this into the stick. The compressor is pumping 20 cuft. Where is the exptra 2 cuft coming from. I submit that it is from the stick whic is supposed to blend the gas with atmosphere air..

IF i am still on track then the solution may be to run the nuvair at 40% so when diluted by atmosphere in the stick it results in your 32. can you post some pics of your set up.

You have my curiosity really peaked at this point. Not necessarily trying this, but what would happen if you put the nuvair into the compressor with out the stick? would it collapse the compressor intake hose?

The stick is the 2 inch PVC as described in the oxy hacker's plan.

inlet tube is 1" ID

I think 6" would give me way too much air, and I would have a lean mixture even with the oxy full blast

im going to look for an LPM reg that goes higher than 15 LPM...... then maybe I could try 4" stick or so....


with the compressor off and calibrated at 20.9, I get around 18% when I star it.

Nuvair told me to calibrated it with the compressor running (oxy off of course) then I get around 23.8 or so when I turn the comp off.


today I had the stick set at 32.5% and was getting around 31.9 at the end of the whip.... got interrupted by someone and the compressor reached its shut off point...

will experiment again on Monday

 

[dchango]

Try to build a bigger stick. I also built a 2” from the Oxyhacker’s book, which I’m sure there are tons of them out there with no problems at all. But after listening to all the folks on the board about too much restriction being bad, I thought why not err on the side caution. And if the trick is to get the O2 to thoroughly mix by the time it reaches the sensor, with little to no restriction. Then I needed to build it bigger, I used a 4”. Here is a link to my post on the Nitrox stick. http://www.scubaboard.com/forums/compressors-boosters-nitrox-trimix-blending-systems/423065-new-nitrox-stick-question.html#post6371868

Damon

 

[Topbodz]

Try to build a bigger stick. I also built a 2” from the Oxyhacker’s book, which I’m sure there are tons of them out there with no problems at all. But after listening to all the folks on the board about too much restriction being bad, I thought why not err on the side caution. And if the trick is to get the O2 to thoroughly mix by the time it reaches the sensor, with little to no restriction. Then I needed to build it bigger, I used a 4”. Here is a link to my post on the Nitrox stick. http://www.scubaboard.com/forums/compressors-boosters-nitrox-trimix-blending-systems/423065-new-nitrox-stick-question.html#post6371868

Damon

Im thinking of doing that. Building another stick with 4" pipe. what size is the part when your sensor is...


I though I would go with a 2" out of the stick & into the compressor to reduce back pressure....

---------- Post added December 9th, 2013 at 05:57 PM ----------

tHERE IS NO SUCH THING AS TOO BIG OF STICK IN REGARDS TO (sorry) compressor protection. You can use a 4 foot culvert for the intake and the compressor will not take any more air than with a 6" input. However too small is another matter. the smaller the intake pipe the quicker you can see the results of a O2 injection change.

Now the other thing with the calibration. I think you are mixing apples and oranges.

Let me understand some things before i continue

You are using a nitrogen removal system, the nuvair bla bla bla. the nuvair is putting out say 32% from it.
you are inputting this into the compressor via a stick.

If i am correct so far, i will say that you problem is that you are leaking air into the compressor. Your nuvair (IE) is putting out 18 cuft of 32% and you are piping this into the stick. The compressor is pumping 20 cuft. Where is the exptra 2 cuft coming from. I submit that it is from the stick whic is supposed to blend the gas with atmosphere air..

IF i am still on track then the solution may be to run the nuvair at 40% so when diluted by atmosphere in the stick it results in your 32. can you post some pics of your set up.

You have my curiosity really peaked at this point. Not necessarily trying this, but what would happen if you put the nuvair into the compressor with out the stick? would it collapse the compressor intake hose?

NO IM NOT USING A MEMBRANNE SYSTEM.... its just a nitrox blending stick. I will rebuild it to 4" and see how that works