Venturi Adjustment Switch ?

[andalucian]

This maybe a silly question but I bought an Aqualung Micra Adjustable regulator from a
buddy last month
and I'm trying to figure out when I need to turn on
the Venturi Adjustment Switch located on top,and what it's purpose is,I understand the adjustment valve on the side is to allow the reg to breath easier but I notice when I switch the top switch to on it free flows out of the water and don't really want that happening at depth can somebody clarify this for me.

Thanks

 

[Mark Vlahos]

This maybe a silly question but I bought an Aqualung Micra Adjustable regulator from a
buddy last month
and I'm trying to figure out when I need to turn on
the Venturi Adjustment Switch located on top,and what it's purpose is,I understand the adjustment valve on the side is to allow the reg to breath easier but I notice when I switch the top switch to on it free flows out of the water and don't really want that happening at depth can somebody clarify this for me.

Thanks

Hi,

I have the standard Micra second stage, and while mine does not have the adjustment dial on the side it does have the lever on top just as your Micra Adjustable does. The use for this lever is as you have already indicated in your message. When you flip the lever to MAX it provides for a free and unobstructed path for the air to go, this results in easier breathing but is more susceptible to free flow. If you turn the lever the other way to MIN it introduces a small obstruction in the path of the air, this turbulance helps to prevent free flow but can make the regulator slightly harder to breathe.

I have the Micra second stage as both my primary and back-up so I leave the primary set for easier breathing (MAX), and I leave the back-up set to MIN to help prevent free flow.

I hope this helps.

Mark Vlahos

 

[Kim]

I have Apeks regs with the same adjustment lever and I do the same as Mark just said. I'm not sure but I think that it's actually not so much of a problem anyway at depth - maybe someone else can clarify that.

 

[Mako Mark]

the venturi switch is essentially to stop the reg free flowing when not in the mouth, and will have very little effect on breathing at depth, that is the job of the tuning adjustment knob.

The venturi effect is when a regulator starts to flow air, the rushing air creates a vacum against the diaphragm, this depresses the valve and opens it further, thus creating a free flow. The switch, blocks the free flow enough so this doesn't happen.

Hope this helps you understand the difference between the venturi switch and the second stage adjustment knob..

 

[andalucian]

the venturi switch is essentially to stop the reg free flowing when not in the mouth, and will have very little effect on breathing at depth, that is the job of the tuning adjustment knob.

The venturi effect is when a regulator starts to flow air, the rushing air creates a vacum against the diaphragm, this depresses the valve and opens it further, thus creating a free flow. The switch, blocks the free flow enough so this doesn't happen.

Hope this helps you understand the difference between the venturi switch and the second stage adjustment knob..

Now it all makes sense.

Thanks

 

[rescuediver009]

Yep, The venturi does not make a huge difference in the breathing effort. But it does depend on the regulatro design and the size of the actual venturi inside the reg. Basically it stops just enough air from flowing to stop and/or prevent the freeflow from happening. Again it will work better on some regs than others. No reason to be worried about it being in one position and not providing air though... You can see why alot of newer divers are thrown off by regs with all the dials and knobs though....

 

[Kim]

I must admit that I didn't really have a clue what the knobs and dials really did until I joined SB! You have to learn somewhere though - that's the true joy of resources like SB. Wow - how the internet has changed our lives!