Quote: (Originally Posted by Faceless)
Reading through your FMECA Volume 8 report i've encountered very interesting idea you're going to implement for monitoring scrubber life: a measurement of differential pressire across the scrubber.
I wonder, how sensitive pressure sensor would be to measure such a small pressure diffs, and how this difference is changing during Sofnolime (or other "magic powder) exhaustion process ?
The scrubber life monitoring is quite different to the WOB monitoring, but WOB happens to use the same sensors.
To monitor scrubber life, our algorithm looks at scrubber temperature using 16 NTC resistors in a scrubber stick and compares that with the heat i should generate based on the gas composition, breathing rate (from which the rate at which CO2 is being generated can be estimated), and flow.
From this data we know what temperature the scrubber should be, and what it is. The difference is a measure of scrubber health. Taking lots of readings one gets a quite accurate result of the scrubber health, and integrating the data, scrubber life: the scrubber is analagous to a battery.
Moving to WOB: for the above scrubber life monitor, breathing rate and flow are measured using two pressure sensors, as that is more reliable than using a differential sensor (the sensors are more reliable). This means we have a source of data we use for monitoring breathing and WOB dynamically.
On the scrubber pressure questions:
1. The scrubbers will only work with Micropore cartridges. The price of these is coming down to equate to Sofnolime on a per hour basis. This decision has many benefits, including completely avoiding tunnelling, dust, all risks of caustic cocktails, as well as giving much better scrubber life and lower breathing resistance. They do require a water pump as the water that is generated by the reaction to absorb CO2 is not absorbed by the lime.
2. The pressure sensors have ample resolution to measure breathing cycles for CCR use: we use two sensors and subtract one from the other digitally. Their type is on the circuit diagrams. We are not trying to chart the exact breathing waveform, just get the tidal volume to within 20% and the breathing rate (accurately).
Hope that answers your query.
As Joe commented, there are many sensors with the resolution to do WOB monitoring, and it is fairly cheap.
Cheers,
Alex