How a Scuba Diving Regulator Works

How a Scuba Diving Regulator Works

When learning about diving, you are shown the diving equipment and how to use it. But often left unexplained is exactly how each component in your dive kit works. This knowledge comes in handy when you are looking to buy your own dive gear since they can be quite expensive. After all, you’d always want to choose the right one that will suit your needs.

And in this article, we aim to help you understand one of the most important pieces of your scuba equipment—your scuba regulator.

What is a Scuba Diving Regulator?

two scuba divers using scuba regulators underwater

A scuba regulator is literally the lifeline between you and your air source while diving. It is the most important and key piece of any diver’s equipment as it connects to the gas cylinder (or tank) and allows the diver to breathe air from the tank. Together, the regulator and tank make up a self-contained underwater breathing apparatus (SCUBA), which is what makes breathing possible underwater.

To help ensure your safety, as well as the proper use of your scuba diving equipment, it helps to know exactly how a scuba regulator works.

How Does a Scuba Regulator Work?

female scuba diver testing regulator above water

Scuba diving is essentially about being able to stay in the water—and at greater depths—for a long time. You’ll obviously need a lot of breathable air, but storing it in its basic form won’t allow you to last long underwater.

The only way that more air can be brought with you underwater is to pressurize and compress it inside cylinder tanks. Divers then rely on scuba regulators to decrease the stored high-pressure air to a much safer pressure level every time they inhale through the connected mouthpiece.

Parts of a Scuba Diving Regulator

scuba regulator complete set-up

Scuba regulators do the critical job of delivering breathable air from pressurized air tanks to divers by working in two stages:

First Stage Regulator

scuba regulator first stage attached to scuba tank

As mentioned above, air is compressed and stored in the tank under high pressure, usually about 3,000 pounds per square inch (psi). In order to reduce this pressure, the regulator first stage, which attaches to the tank valve, lowers the tank pressure to intermediate pressure (about 140psi) for release into a hose that leads to the regulator’s second stage.

The valve in the first stage opens to let some air into the hose and then closes again. The exact process, of course, also depends on your scuba tank’s valve type. The regulator also compensates for the decreased pressure in the tank as the air is used and as the diver changes depth, which changes the ambient water pressure.

Second Stage Regulator

scuba second stage regulator on wooden surface

The second stage of a scuba regulator is the part that goes into your mouth. It contains a mechanism that further reduces the intermediate pressure in the hose coming from the first stage to the surrounding water pressure, making it comfortable and easy to breathe. As with the first stage, the second stage also contains a piston or diaphragm construction which starts and stops the airflow.

The mouthpiece, exhaust valve, and an emergency purge valve (or button) are all part of the second stage of the scuba regulator. The exhaust valve lets the air escape into the water when you exhale. It is a one-way valve and does not allow water to enter from the outside. When the purge button (usually the front cover of the second stage in modern models) is pushed, it forces air to flow continuously into the second stage chamber forcing any water out of the mouthpiece through the exhaust valve.

With this mechanism, divers are actually able to vomit while holding the second stage in their mouths instead of pulling it out and risking accidental water inhalation. It’s not pleasant to think about, but what is nice to consider is that this wonderful piece of technology makes it possible to survive underwater—even in the least optimum conditions—until you can safely return to the surface.

To gain a much better understanding of the different parts of a scuba diving regulator and how they work, check out this video below:


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