1 Counter lung vs 2?

[lostsheep]

What are the tradeoffs between having a single counter lung vs two?

Ease of manufacturing? Form factor? Work of breathing? Flood tolerance? What am I missing?

 

[Whitrzac]

Are there any rebreathers made in the past 20 years that use 1 counterlung?

 

[Gone for diving]

No an expert but from my understanding.
Flow through the scrubber is slower.
And better breathing characteristics in different positions (usually).

 

[lostsheep]

No an expert but from my understanding.
Flow through the scrubber is slower.
And better breathing characteristics in different positions (usually).

I believe volume flow rate through a closed system to be mostly constant therefore velocity of the gas at any point would be determined by the cross sectional area at that point. I could see velocity decreasing in the counterlungs as they expand but not through the scrubber. Can you expand on your thinking there?

Are there any rebreathers made in the past 20 years that use 1 counterlung?

Sidewinder

 

[Marie13]

Are there any rebreathers made in the past 20 years that use 1 counterlung?

This looks like one to me. Kiss Spirit.

 

[lostsheep]

@Rol diy , not saying you're wrong just trying to wrap my head around what's happening.

 

[Whitrzac]

Sidewinder

Forgot about those/spirit. I was thinking normal rebreather, not specialized sidemount/cave gear.

 

[macado]

RB80 and SF2 both use single bellows counterlung.

I can only speak for the SF2 but the one potential downside is counterlung volume.

Due to the position of the counterlung the SF2 dewaters VERY easily. Work of breathing is very position dependent

 

[Gone for diving]

@Rol diy , not saying you're wrong just trying to wrap my head around what's happening.

I would totally agree, but that is what I have read , and that has confused me a bit as well.
But in theory, if both counterlungs are in the same plane, the fast exhale gets stored, and it can slowly equalize...
But in practice I don't think it really matters for the scrubber any ways..

 

[Gone for diving]

You planning to build one?
Oxydiver has very interesting ones on his site.