blowing the sensor with diluant

wearypanda · 19th November 2007, 21:41

Quote: (Originally Posted by jmurba)

it would be great if a pelagian rebreather diver could tell us if it works good and if these injections are not bad for the sensors.

The instant validation works very well indeed. The way this operates is that you exhale out of the loop and then make your next inhalation long and slow which triggers the ADV. The displays respond very quickly and as well as validating the PO2 of the diluent at your known depth it gives you an opportunity to assess how quickly (or not) each cell responds to the change in PO2. This is certainly a much faster way to validate your cells than loop flushing and it uses a lot less diluent. As a result I would routinely do a cell validation at least two or three times during a dive. It has my vote and was a major factor in choosing the Pelagian.

Virtually the same procedure allows you to blow diluent obliquely across the face of the cells to clear them of condensation. The only difference is that this requires a more rapid inhalation to trigger the ADV and pull diluent into the head fast so as to blow moisture off the cell membrane. It is more difficult for me to assess how effective this is. I cannot say for sure that I have had any cell anomoly which was obviously caused by moisture. However, I certainly have not had any cell problems caused by using this feature of the Pelagian.

**jmurba** · 19th November 2007, 21:43

Quote: (Originally Posted by Dave Sutton)

I simply tapped into the existing Inspiration diluent manifold, so it was using the normal first stage gas provided by the onboard regulator.

Not that it really makes a huge difference, but the system I built used the standard modified wings inflator for adding gas, and I retained the quick connect. Theoretically, any gas could be plugged in there, and as it's a completely redundant gas addition pathway, could be used as a substitute manual add valve if the main rig manual add valve failed. Either diluent or 02 could be fed to that port.

Dave

do think a restrictor is necessary to reduce the flow ti 4 liter minutes ?
is is 4 liter/minutes per sensor or 4 liter/minutes in all ?
regards
jean mi

**Dave Sutton** · 19th November 2007, 23:52

Quote: (Originally Posted by jmurba)

do think a restrictor is necessary to reduce the flow ti 4 liter minutes ?
is is 4 liter/minutes per sensor or 4 liter/minutes in all ?
regards
jean mi

It's not that complex as to require any certain flow... I guesses that it was about 4 LPM total across all three cells. All I did was to use small diameter tubing, which naturally limited the flow rate. Even with the BC valve full depressed, the volume was "adequate" but not harmful to the cells. Since the BC inflator valve is able to be squeezed very gently for small flows, the diver can control the flow with ease. Squeeze a little to validate, squeeze harder to dry the cell face. Very intuitive.

Dave

Edvin M · 30th November 2007, 17:12

does anyone have any pictures of Pelagian's system?

19th November 2007, 21:41	#11 (permalink)
wearypanda New Member Current Rebreather/s: Pelagian Other Rebreather/s: Inspiration Classic Pelagian Join Date: Oct 2006 Location: Wiltshire, UK Posts: 88	Re: blowing the sensor with diluant Quote: (Originally Posted by jmurba) it would be great if a pelagian rebreather diver could tell us if it works good and if these injections are not bad for the sensors. The instant validation works very well indeed. The way this operates is that you exhale out of the loop and then make your next inhalation long and slow which triggers the ADV. The displays respond very quickly and as well as validating the PO2 of the diluent at your known depth it gives you an opportunity to assess how quickly (or not) each cell responds to the change in PO2. This is certainly a much faster way to validate your cells than loop flushing and it uses a lot less diluent. As a result I would routinely do a cell validation at least two or three times during a dive. It has my vote and was a major factor in choosing the Pelagian. Virtually the same procedure allows you to blow diluent obliquely across the face of the cells to clear them of condensation. The only difference is that this requires a more rapid inhalation to trigger the ADV and pull diluent into the head fast so as to blow moisture off the cell membrane. It is more difficult for me to assess how effective this is. I cannot say for sure that I have had any cell anomoly which was obviously caused by moisture. However, I certainly have not had any cell problems caused by using this feature of the Pelagian.
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19th November 2007, 21:43	#12 (permalink)
jmurba wet bear Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: May 2006 Location: cannes france Posts: 672	Re: blowing the sensor with diluant Quote: (Originally Posted by Dave Sutton) I simply tapped into the existing Inspiration diluent manifold, so it was using the normal first stage gas provided by the onboard regulator. Not that it really makes a huge difference, but the system I built used the standard modified wings inflator for adding gas, and I retained the quick connect. Theoretically, any gas could be plugged in there, and as it's a completely redundant gas addition pathway, could be used as a substitute manual add valve if the main rig manual add valve failed. Either diluent or 02 could be fed to that port. Dave do think a restrictor is necessary to reduce the flow ti 4 liter minutes ? is is 4 liter/minutes per sensor or 4 liter/minutes in all ? regards jean mi __________________ when will I be able to think about something else then spending hours underwater, when will I be normal ? http://web.mac.com/jmurba/Site_2/home.html http://web.mac.com/jmurba/Site_3/home.html
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19th November 2007, 23:52	#13 (permalink)
Dave Sutton Living on Animal Farm Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Classic Kiss rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,511	Re: blowing the sensor with diluant Quote: (Originally Posted by jmurba) do think a restrictor is necessary to reduce the flow ti 4 liter minutes ? is is 4 liter/minutes per sensor or 4 liter/minutes in all ? regards jean mi It's not that complex as to require any certain flow... I guesses that it was about 4 LPM total across all three cells. All I did was to use small diameter tubing, which naturally limited the flow rate. Even with the BC valve full depressed, the volume was "adequate" but not harmful to the cells. Since the BC inflator valve is able to be squeezed very gently for small flows, the diver can control the flow with ease. Squeeze a little to validate, squeeze harder to dry the cell face. Very intuitive. Dave __________________ . "All animals are equal, but some animals are more equal than others" Professional Small Boy: Never Successfully Cubicled.
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30th November 2007, 17:12	#14 (permalink)
Edvin M New Member Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Aug 2007 Location: Lysekil, Sweden Posts: 84	Re: blowing the sensor with diluant does anyone have any pictures of Pelagian's system?
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