Wow! Meg design - dont know if I like this

**wedivebc** · 26th June 2008, 05:58

Quote: (Originally Posted by UKSteve)

From an interested observer...

Would the impact of entering the water be a potential time of failure of a weak cell? Not sure what axis the cells sit on in a meg and whether you generate a shearing force on the body of the cell when you decelerate on hitting the water. Similarly, impact loads on the unit on a rough passage on a boat could cause cell failure?

If this is so then a check during assembly of the unit ashore might not offer as much protection from the failure mode identified by Mike as you might wish. Makes another strong case for a good pre-breath tho.

Steve

Actually no, the cells face down so any downward force would actually push the cell body back together.

zzzzzzzz · 28th June 2008, 12:15

Based on the diagram provided in the original posts, it would appear as though the cells have favorable positioning wrt the differential pressure based on loop configuration.

The inhale will, on average, have lower pressure than the exhale side. The cells will experience pressure forces that maintain their position.

Pressure waves would need to be applied only to the inhale counterlung to affect the cells, and the maximum pressure observed at the cells would be limited by the mushroom valve cracking pressure.

Gas injection would be another source of differential pressure, don't know where theinjection point is though.

Would likely only have any influence if the inhale hose were obstructed or crushed.

26th June 2008, 05:58	#211 (permalink)
wedivebc Dave Tomblin Current Rebreather/s: Megalodon Other CCR Other Rebreather/s: Not Bought Yet Inspiration Classic Sport Kiss Other CCR Join Date: Feb 2005 Location: Vancouver Island BC Canada Posts: 1,444	Re: Wow! Meg design - dont know if I like this Quote: (Originally Posted by UKSteve) From an interested observer... Would the impact of entering the water be a potential time of failure of a weak cell? Not sure what axis the cells sit on in a meg and whether you generate a shearing force on the body of the cell when you decelerate on hitting the water. Similarly, impact loads on the unit on a rough passage on a boat could cause cell failure? If this is so then a check during assembly of the unit ashore might not offer as much protection from the failure mode identified by Mike as you might wish. Makes another strong case for a good pre-breath tho. Steve Actually no, the cells face down so any downward force would actually push the cell body back together. __________________ Cheers, Dave.... Man is the only animal burdened with the knowledge he will eventually die
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28th June 2008, 12:15	#212 (permalink)
zzzzzzzz Custom Title Allowed! Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Dec 2006 Location: Earth Posts: 100	Re: Wow! Meg design - dont know if I like this Based on the diagram provided in the original posts, it would appear as though the cells have favorable positioning wrt the differential pressure based on loop configuration. The inhale will, on average, have lower pressure than the exhale side. The cells will experience pressure forces that maintain their position. Pressure waves would need to be applied only to the inhale counterlung to affect the cells, and the maximum pressure observed at the cells would be limited by the mushroom valve cracking pressure. Gas injection would be another source of differential pressure, don't know where theinjection point is though. Would likely only have any influence if the inhale hose were obstructed or crushed. __________________ z
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