ACSC based on pneumatic valve.

mammut

Hello everybody :-)

I' thought about simple rebrather for diving to 30-40 meters. For this range
of depth , typical are SRC rebreather witch sonic jet. In example : Dolphin,
Submatix, Ray , etct. But in my opinion, scr should be safetly by him self.
Every rig witch sonic jet , require OxyGauge. Better way is PSCR - "as long
as you can breath- everything is OK" But , pscr has got great consumption
at greater depth.

For my the best solution is ACSC or DCSC. These rig was build by
Interspiro and checked to 450 meters. ACSC counts volume of breatch
and added them. After constant re-breath volume , added constant *mass*
of fresh mix. Time of diving is depth independent, but depended of
workload. Ist a most economic scr. This rig reqiure one-way cluth- and its a
problem (cost).

I 'v got hope solving problem with cluth by using pneumatic valve.
I showed my idea on picture above .




How does it work ?

This rig containt all typical elements. Mouthpiece (1) , scrubber(2) , and
counterlungs (3) and (4) <similar as in pscr>. But, insaid CL (4) doesnt
put gas out of rig. Its important. ;-) Device is supplied from first
stage reductor, pressure in line is about 9-10 bar above external
preasure<its very important>

Exhale.
- diver exhale gas to mouthpiece (1)
- gas is provided to counterlung (3)
- part of exlaled gas going to instide lung (4) througt one-way valve

Thats all :-)

Inhale.

- diver starts inhale
- gas from lung (3) going througnt scruuber (2) to mouthpiece(1)
- gas from lung (4) going to valve (5) < its a typical 5/2 valve
from pneumatic cabinet>
- from valve (5) gas going to upper part of chamber (8) , as long
as diaphragm going down and open valve (6)
- gas from bottom part of chamber going to valve(5) and to
scrubber (2) throught line (17)
- valve (6) , increase pressure in line (13) (14)
- valve (5) and (10) change status
- valve (5) providing gas form lung (4) to bottom part of chamber (8)
- valve (10) providing gas to chamber (9) <constant volume>

If diver sill making inchale ...

- gas from lung (4) going to bottom part of chamber (8)
- valve (6) closed, butl line (13)(14) still pressurized
- diaphragm open valve (7)
- line (13) (14) depresurized , to line (15)

<line (15) could be conneted to scrubber- its add little amount of gas

- valve (5) (10) change status
- mix from chamber (9) is providing to scrubber (2)

I think :
- lung (4) schould be about 10%of all lung volume
- chamber should have obout 1/4 of lung (4) volume

By this way , injection of fresh gas will be make for every half
of volume all lung.

Problem with this rig :

Fresh mix is added to all volume in lung , and in example:

Ex1

- lung volume 3 dm3 - 17% of oxygen
- volume added 1 dm3 - 40 % of oxygen

it ' givs *3dm3* of 22,7% of oxygen in inhale mix

it, meand so you lost 1 litre of mix :-( , and itst lost 25% ! - it means
so ratio isnt x4 but x3

Much worse situation is for mix 32%

Ex 2
- lung volume 3 dm3
- volume added 2 dm3

is givs still *3dm3* of 23% oxygen's mix , and it means - you lost
2 litres per every 5 liters - it measns - lost of 40% !!

Of coure, its a problem only near surface. Because when the diver
going depper , added mix will have the same masses but litter volume.

For Ex1 :
- at surface lost 25%
- at 10m - 12,5% (because volume of added gas was decreased)
- at 20, - about 8%
- at 30m - about 6% - and that is maksimum operation depth

Now , I think about change construction of lung which solve
this problem . I' think about using next lung , inside bigger lung.
If I'm not wrong , its allows using normal air of supply gas:-)
Of coures ratio will be 1:1. It measn - you need the same amount
of air (mix) instead of depth ;-)


And , at the end:-)

What do You thing about this idea?

Attached Images

reb01.jpg (39.4 KB, 107 views)

Hanssing

As you know the Sonic-jet version is also constant mass, however the addition is independant of workload contrary to your concept.

If the concept works you gain the advantage of a more constant O2 versus workload. But is the added complexity worth it for such depth?
And are you going to work at depth, since you need it?

It would seem that you gain very little over the sonic SCRs at the depth youre proposing. And that your limited by the same restrictions.

But for a for-fun project it sounds great.

Nicolai

__________________
Woohooo - I can change my rEvo!
Its going to be bitchin' tricked out piece of gear