Dive/Predive levers?
- Thread starter Loewely
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I'm not sure about other regs, but the Apeks have them. In the Apeks, they're a "venturi assist" lever. Basically, the lever turns a little piece of plastic inside the regulator body. In the pre-dive mode, the piece of plastic is angled so that it deflects air coming out of the valve towards the diaphragm, pushing it out. In dive mode, the plastic deflects the air towards the mouthpiece.
In pre-dive, airflow out of the valve against the diaphragm helps prevent freeflow by tending to shut the valve. In dive mode, airflow directly to the mouth makes it easier to breathe, but lack of air 'filling' the body and pushing against the diaphragm makes it more likely to freeflow.
I'm not sure if it's similar in other regs.
In pre-dive, airflow out of the valve against the diaphragm helps prevent freeflow by tending to shut the valve. In dive mode, airflow directly to the mouth makes it easier to breathe, but lack of air 'filling' the body and pushing against the diaphragm makes it more likely to freeflow.
I'm not sure if it's similar in other regs.
armyscuba
Contributor
Loewely:
PreDive and Dive levers are not necessary..They do aid in Free-Flow activity prior to descending. They reduce sensitivity in the breathing of the Regulator. Depending on how you have Your regulator set..If adjustable. + or - Don't base Your selection on a Regulator if they do or do not have them though.
IslandHopper
Guest
Scuba Pro has the same feature ... the description given previously fits the SP models as well....
You can breath just fine with them in EITHER position, and the do slightly decrease the ease of free-flow when it's just hanging there ...
I leave mine in the pre-dive position all the time. It makes that little difference when breathing.
You can breath just fine with them in EITHER position, and the do slightly decrease the ease of free-flow when it's just hanging there ...
I leave mine in the pre-dive position all the time. It makes that little difference when breathing.
They can consist of either an adjustable flow vane or an actual switch or lever that increases the force required to depress the demand lever.
On an adjustable secodnstage where the cracking effort can be increased they are overkill.
They are however nice to have on an octo to prevent unintentional air loss. They are also nice to have on finely tuned non adjustable regs like the D400 that may otherwise freeflow slightly while you are working in some strange attitudes.
On an adjustable secodnstage where the cracking effort can be increased they are overkill.
They are however nice to have on an octo to prevent unintentional air loss. They are also nice to have on finely tuned non adjustable regs like the D400 that may otherwise freeflow slightly while you are working in some strange attitudes.
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