Brainx3

Which type/model do you use on your mCCR/hCCR ?



Regards. Wael

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Euro Diving Zone (HP Kevlar Fiber Hoses, LP Thermoplastic Hoses, Oxygen Boosters, Carbon Fiber Cylinders, SS Fittings)

TDI Inspiration/Evolution Instructor

SITEC Oxygen Boosters

stunsm

With the Dolphin, I used the Dwyer MiniMaster, the same model that came with the Dolphin could be bought directly from dwyer for a fraction of the cost. For mCCR, I use the "Dave ****** inverted graduated cylinder in a bucket of water" method, the output hose from the orifice goes into the water, and bleeds gas over time into a flooded and inverted graduated cylinder. The amount of water displaced, factored with the time of the sample (example: 125ml in 10 seconds= 0.75 liters/min), gives an actual reading of gas volume per minute, without having to worry about whether the calibrations of the flow meter is in air or O2. Seems to have worked well for me so far.

lizardland

I used a Dwyer, can't remember the model number but Gordon lists it in the KISS manual. IIRC it's a 0-2l/min but might be wrong as it's from memory. You will need to correct for oxygen as they are calibrated in air.

Once you have the flow set then you can check the flow in the field by just timing how long it takes the oxygen lines to depressurise once the oxygen is switched off. It's rough but it's an easy check to do predive.

Hanssing

ahh for a mCCR/hCCR --> none.

Get the pressure to match your metabolism, and write down droptime from say 100 to 50 bars. Use this as a ballpark figure during preparation at home.

I still see this as a "critical" function on a mCCR, and therefor I test it during preparation of the rig at home.
However, so what if it doesnt?
We check PPO often enough right......

Nicolai

jcmankat

+1 for Dwyer. Mine is an 02 flow meter, so no calculation from air needed.

below is pic of it.. Albeit not the best photo.. hope it helps..

John

Attached Images

flow meter.jpg (37.9 KB, 4 views)

cadblaster3

I use the Dwyer Model # VFB -60-SS, which you can order directly. Lately thought it's simpler to use an empty Jim Bean 1/5. 750ml,, so 1 minute to fill equals .75lpm flow..........

Ivan Calcoen

I use the Dwyer 1,2 l/m purchased through Tecme. (air model)
I use it every time doing predive checks.
If anything is wrong, its easy noticed :
Flow too high : ball above .. happened to me once due to O² IP creeped up
Flow too low : filter clogged, re-adjustment of y Swagelock needle valve.

cheers

Ivan

RebreatherNut

Second that, I also use a flow meter which i purchased from Martin (tecme)

venturi

Anyone have an idea of the real difference with calibrating 02 with an air meter ?

Scuba_Vixen

I'd estimate that it reads about 5% high.
That's about 1/4 of the indicator ball's diameter, if that.