Full face mask with a GAS SWITCH BLOCK..

[rjack321]

The isolation manifold for the Z-system is a needle valve, identical to the valves on your scuba tanks,

Scuba tanks do not use needle valves and I don't think the UTD manifold block is either. Both are fast opening nylon seat to orifice valves.

Needle valves are often used on O2 whips and such. The only underwater use I can think of is to adjust the O2 delivery rate on a mCCR when you can't used a fixed IP 1st stage and orifice because you want to go deeper than the IP of the reg (mid 200ft or so). You have to adjust the orifice as the IP changes with depth to maintain an appropriate O2 mass flow rate, very fine scale changes which is what needle valves are good at.

 

[_Arthur_]

That could be cool [emoji57][emoji106]


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[thenewN2O]

This has been a somewhat helpful thread.

I am a rec diver with a poor immune system. I wear a FFM to mitigate the risk of ingesting water. Without my nose and mouth covered, I am very susceptible to bad infections. All the other benefits of FFMs are secondary to me, but I enjoy dives more with my Ocean Reef. I have become very good at mask replacement procedures and switching to the octo and spare mask, though I haven't needed to do that on a dive yet.

I am making a switch from back mount to side mount for the reasons we all like them. Plus it is cool and I like different gear. For now, I am going to dive a single cylinder and not really change anything. The cylinder goes on my side instead of my back.

But with time and training, it is my goal to do some deco dives. In these cases it is good to see that TDI has embraced FFMs and built training around it. I know it isn't perfect or completely fail safe and adds complexity and potential for failure, but given my special cases it seems like Option 1 would be my only other choice.

 

[Rich Keller]

I have become very good at mask replacement procedures and switching to the octo and spare mask, though I haven't needed to do that on a dive yet.

The Kirby Morgan M-48 Mod 1 mask is something you might be interested in for this. The mask is modular so you can remove the reg and go to your octo without having to take the mask off. This eliminates the need to carry a spare mask and reduces the amount of time it takes to switch to your octo.

M-48 MOD-1 | Kirby Morgan

Here are the Navy test results for the M-48.

View attachment ADA446510.pdf

 

[thenewN2O]

Rich, the Kirby Morgan looks like it can be what I should use for deco dives. I will read more about it, as I'm left with a few questions/concerns, such as if I will need to setup my buddy's regs with pods as well.

I would miss some features of the Ocean Reef masks (fogless, no flooding, field of view, self-clearing if necessary). Safety over convenience though.

 

[Rich Keller]

Once you remove the reg from the M-48 you can use a normal octo without having to do any modifications. The M-48 can also be used with a side block that will allow you to switch from one air source to another without removing the mask if your deco gas is different from primary gas. Parts for this system are also available to anyone who uses them unlike scuba FFM systems that requires you to go to a LDS for service.

 

[MSargeant]

From my own experience, I really dislike Kirby's, uncomfortable and just a ballache compared to things like the Apeks/Draeger panorama/similar. Again though, my own experiences.

 

[decompression]

Scuba tanks do not use needle valves and I don't think the UTD manifold block is either. Both are fast opening nylon seat to orifice valves.

Needle valves are often used on O2 whips and such. The only underwater use I can think of is to adjust the O2 delivery rate on a mCCR when you can't used a fixed IP 1st stage and orifice because you want to go deeper than the IP of the reg (mid 200ft or so). You have to adjust the orifice as the IP changes with depth to maintain an appropriate O2 mass flow rate, very fine scale changes which is what needle valves are good at.

100 % correct, Rjack.

No needle valve here......



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