Can anyone translate this graph?

[Rick Inman]

See the attached jpg below.
Can anyone explain to me exactly what this graphic is saying?
When I first got back into diving, I bought this regulator for the worst reason a person can: It was cheap. Lately I’ve been looking to by a better one, but after breathing some SPs, Apek, etc., I realized that I really like the way this Prosub breathes. Maybe I’m just used to it, but who cares if it works and I like it.
Anyway, I ran across this graph and I don’t understand it.
Thanks for the help!

 

[Rick Inman]

BTW. here's the lint to the whole page on this reg:
http://www.prosub.de/download/lungenau.pdf

 

[MechDiver]

The graph is showing the Work of Breathing. The WOB shows how easy, or difficult, the regulator works under a set of test conditions and it used primarily as a comparison to grade how well the system works "under load" as it were.

WOB consists of cracking effort, sustain, and exhaust effort.

The lower the WOB, the better.

MD

 

[chrpai]

It's marketing speak for....


Buy our product.

 

[Rick Inman]

So should I be looking at the graph from right to left, starting at "cracking effort" (which I assume means the effort it takes to start the air flowing), following the bottom line until it kicks up above into the exhale area? Is that right? In other words, we fall below the "natural breathing" line at both the beginning and end of the breath inhalation? Or am I all wigged out on this?

 

[jonnythan]

Rick Inman once bubbled...
So should I be looking at the graph from right to left, starting at "cracking effort" (which I assume means the effort it takes to start the air flowing), following the bottom line until it kicks up above into the exhale area? Is that right? In other words, we fall below the "natural breathing" line at both the beginning and end of the breath inhalation? Or am I all wigged out on this?

You're close. The natural breathing line is the ideal. That line is what the normal work of breathing on the surface is. No regulator out there will give you that line. You're reading the graph correctly.... basically it shows that there's some cracking pressure (the pressure you have to inhale for the regulator to deliver air), virtually no pressure required to continue the breath, then it takes a bit of force to exhale, which you'd expect.

http://www.divernet.com/gear/regs398/ansti398.htm gives a good explanation and has graphs for lots of regulators. If that graph represents real breathing performance, it means it's a nice easy breathe. Keep in mind that with regs there's more or less a "good enough" level and you have to start looking at other features of the reg beyond that level. It's also very subjective.. low numbers don't automatically mean a nice breathe.

 

[jonnythan]

Rick Inman once bubbled...
Lately I’ve been looking to by a better one, but after breathing some SPs, Apek, etc., I realized that I really like the way this Prosub breathes. Maybe I’m just used to it, but who cares if it works and I like it.

Exactly. If you like it, stick with it.

 

[Rick Inman]

jonnythan once bubbled...


You're close. The natural breathing line is the ideal. That line is what the normal work of breathing on the surface is. No regulator out there will give you that line. You're reading the graph correctly.... basically it shows that there's some cracking pressure (the pressure you have to inhale for the regulator to deliver air), virtually no pressure required to continue the breath, then it takes a bit of force to exhale, which you'd expect.

http://www.divernet.com/gear/regs398/ansti398.htm gives a good explanation and has graphs for lots of regulators. If that graph represents real breathing performance, it means it's a nice easy breathe. Keep in mind that with regs there's more or less a "good enough" level and you have to start looking at other features of the reg beyond that level. It's also very subjective.. low numbers don't automatically mean a nice breathe.

Exactly. If you like it, stick with it.

Thanks! That clears it up.