Home >> Diving regulator second stage

The regulator is the main piece of scuba equipment. It allows one to breathe while underwater. The regulator may either be first or second stage. Well, though first stages are quite important, it’s the second stages that decide the personality of your regulator. Why so? The second stages determine whether the unit allows for easy or hard breathing, how good it looks to the rest of the world as well as how it feels to the diver.

Compact Second Stage

This is around 75% the size of the normal second stage though in some cases it could be less than half the normal size. This design gives a lighter physical weight therefore lowering jaw fatigue. Some could even be smaller to offer even greater comfort during the longer dives. Smaller second stages also have lesser dead air space which helps in reducing any potential buildup of carbon dioxide.

Side Vented Second Stage

A side vented regulator exhausts air exhaled from the normal second stage to one side giving a clearer view. A few side vented second stages may be used either way up which makes them ideal for use as alternate air sources (octopus).

Purge Button

This is located on the face of the second stage. Its purpose is flooding the second stage with air, which forces water out. Divers usually use this button when this stage has been filled with water, for example when a diver gets rid of the regulator from the mouth while performing the regulator recovery skill.

Ease of Breathing Adjustment

Most regulators have knobs that allow the diver to change the level of breathing resistance. This feature prevents regulator free flow (the state whereby air flows quickly out of the second stage without the diver breathing from it). This typically occurs when breathing resistance has really lowered. Free flows can rapidly empty a tank. Most second stage adjustments come with 2 settings, one labeled "pre-dive" to prevent free flow on the surface, and the other labeled "dive" to allow for easier underwater breathing. As the divers descend, they can change the ease of breathing as a way of compensating for the greater difficulty of breathing as they descend.

Exhaust Valve

The exhaust valve is a plastic unit which channels exhaled air bubbles from the diver's face. Usually located below the regulator's mouthpiece, it channels air down and towards the sides therefore keeping the diver's field of vision free from bubbles.

Mouthpiece

This is the part of the second stage the diver bites down on. Most high-quality mouthpieces are made from soft rubber (non-plastic) or silicon, and come in a wide variety of sizes and shapes to fit to divers' mouths. They also are replaceable and removable. A diver ought to check his mouthpiece to ensure it is secured to the second stage with a cable tie or zip tie to ensure that it doesn’t slide off when diving.

FUNCTIONS

To lower intermediate-pressure air traveling through a regulator hose to an ambient pressure (the pressure of the surrounding water) that a diver can breathe comfortably and safely. (For example, 1 to 5 ATM depending on the depth)

To supply air, either only when the diver inhales (typical operation) or continuously (emergency operation).

To remove any waste air or any other object as need arises.

You need assurance about the part you put onto your mouth – the single most important part of your diving mechanism. Regulator second stages provide you that assurance. The assurance of easy, comfortable and natural breathing whichever the depth. So breathe easily and have a great dive.