DiveNav has closed

[rhwestfall]

could.... will they stand behind it? Dwyer is a recognized name, and I got a calibration certificate with it. The engineer in me appreciates the finer product, and in honesty, it isn't a bunch more in the grand scheme of things...

 

[guruboy]

I dont remember seeing a flow rate specified for the CO calibration. What are you guys using?

 

[tursiops]

DiveNav says the flow rate through their ball at the end of the Cootwo is limited to 0.5 l/min. So any flow rate higher than that is probably OK.
The Sensorcon flow calibration rate should be 0.5 l/min (but you have to limit it yourself), so that's a good all-around number.

 

[rhwestfall]

Higher flow rate can lead to erroneous readings

 

[aviator8]

My completely unscientific way of getting the flow rate is to use the BC adapter on the QD LPI and listen to the flow rate. I then duplicate that sound by adjusting the regulator on my bump gas for calibration. I then check it by measuring my breath expecting to get a 2-4ppm reading and a final check back against bump gas expecting to get 20ppm and that has worked well enough for me.

 

[tursiops]

Higher flow rate can lead to erroneous readings

You don't trust the DiveNav statement that their ball limits the flow to 0.5 l/min?

 

[aviator8]

You don't trust the DiveNav statement that their ball limits the flow to 0.5 l/min?

I think he meant calibrating at a higher rate, instead of the measuring rate.

 

[rhwestfall]

You don't trust the DiveNav statement that their ball limits the flow to 0.5 l/min?

no, never saw that, and would need to see it to believe it. I recall that they said it needed to be 0.5 lpm flow into the ball for accuracy...

 

[KDAD]

Higher flow rates can start to pressurize the sample which may lead to erroneous results.

 

[tbone1004]

@rhwestfall the cap with the BC connector is restricted for that flow rate at normal regulator IP's. Has to be for the O2 sensor to work properly since that's reading ppO2 and is heavily influenced by pressure inside of the housing. Unsure what the pressure from the CO2 regulators would be though and their IP will obviously impact the flow