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AD_ward9 · 21st July 2008, 11:55

Quote: (Originally Posted by paulraymaekers)

Hello Alex, in what way is Micropore involved in the whole project?

We collaborate to get better functionality and efficiency. Nothing sinister. On the advise costing half the unit: we look to instructors to give advice. They charge a fee for training, and need to provide that training. It will not have nice long customer chats on the phone: it is a product described with a datasheet, and the only advice is a list of trainers. This training element is the bottleneck for the shipments, so is getting a lot of attention.

A few people have emailed me on the combined ADV and BOV, with auto loop shut off. We did think long and hard about this, and also sponsored another company who were trying to do this for quite a while (they packed it, so we did our own). Here is the philosophy behind it:

If a diver needs 10/50 when below 60msw, then he should not plug 10/50 into his ADV on the surface. Doing this is a factor in more than one fatal accident.

Safe diving demands that the ADV gas be breathable at the depth the diver is, so he can perform a flush safely, and preferably with enough oxygen that if the O2 injection fails, he can ascend in SCR mode. This means that for dives where hypoxic gases are need, then the diver should use a gas switching manifold, or gas connectors.

Many divers are going well beyond their experience with rebreathers deep, and the lack of gas switching is one of the signs of that. Putting a hypoxic gas into an ADV is a hazardous practice: ADVs also free-flow, and there are various points where the diver reduces the loop PPO2. For example, on water entry most divers trigger the ADV, when stepping off the boat they often go off the loop to say something and breathe a lung full of air into the loop when they come back on reducing the PPO2. All it takes is the O2 to fail or be off, and the diver is going to be out quickly if the ADV dilutes the PPO2 even further and the rebreather fails to deliver O2 at the same time (it is not unknown for divers to run out of O2

).

By putting the ADV and bail out as one in front of the diver's mouth, the intent is to make it obvious how hazardous using a gas in the ADV that is not breathable actually is.

On the original Inspo, there was no ADV and trimix divers had two buttons for gas addition. This was nice and safe, for divers at that level. The wider user base needs an ADV, but when ADVs replace those buttons, the buttons have to migrate to a gas switching block. We don't see any extra hazard from putting the ADV on the diver's mouthpiece: it might avoid divers using hypoxic gases without a switch block.

Alex

21st July 2008, 11:55	#154 (permalink)
AD_ward9 RBW Member Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 2,016	Re: Any news? Quote: (Originally Posted by paulraymaekers) Hello Alex, in what way is Micropore involved in the whole project? We collaborate to get better functionality and efficiency. Nothing sinister. On the advise costing half the unit: we look to instructors to give advice. They charge a fee for training, and need to provide that training. It will not have nice long customer chats on the phone: it is a product described with a datasheet, and the only advice is a list of trainers. This training element is the bottleneck for the shipments, so is getting a lot of attention. A few people have emailed me on the combined ADV and BOV, with auto loop shut off. We did think long and hard about this, and also sponsored another company who were trying to do this for quite a while (they packed it, so we did our own). Here is the philosophy behind it: If a diver needs 10/50 when below 60msw, then he should not plug 10/50 into his ADV on the surface. Doing this is a factor in more than one fatal accident. Safe diving demands that the ADV gas be breathable at the depth the diver is, so he can perform a flush safely, and preferably with enough oxygen that if the O2 injection fails, he can ascend in SCR mode. This means that for dives where hypoxic gases are need, then the diver should use a gas switching manifold, or gas connectors. Many divers are going well beyond their experience with rebreathers deep, and the lack of gas switching is one of the signs of that. Putting a hypoxic gas into an ADV is a hazardous practice: ADVs also free-flow, and there are various points where the diver reduces the loop PPO2. For example, on water entry most divers trigger the ADV, when stepping off the boat they often go off the loop to say something and breathe a lung full of air into the loop when they come back on reducing the PPO2. All it takes is the O2 to fail or be off, and the diver is going to be out quickly if the ADV dilutes the PPO2 even further and the rebreather fails to deliver O2 at the same time (it is not unknown for divers to run out of O2 ). By putting the ADV and bail out as one in front of the diver's mouth, the intent is to make it obvious how hazardous using a gas in the ADV that is not breathable actually is. On the original Inspo, there was no ADV and trimix divers had two buttons for gas addition. This was nice and safe, for divers at that level. The wider user base needs an ADV, but when ADVs replace those buttons, the buttons have to migrate to a gas switching block. We don't see any extra hazard from putting the ADV on the diver's mouthpiece: it might avoid divers using hypoxic gases without a switch block. Alex Last edited by AD_ward9 : 21st July 2008 at 14:44.
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