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Diving Regulators

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Diving Regulators

Diving Regulators supply a diver with breathing gas while they’re underwater. Without a Diving Regulator, you would not be able to stay underwater for a long period of time. The gas that a diver breathes can be air, or can be specially blended breathing gas.

Many people love to dive, and/or go scuba diving. A Diving Regulator is part of a scuba set, and arguably the most important part. A faulty Diving Regulator is a worthless regulator and ultimately could be a fatal regulator if a diver is too deep.

Always make sure to check your regulator before every trip or dive. They are usually good to go, but better be safe than sorry. Always make sure to refill the tank often as well.

A gas pressure regulator has one or more valves in series, which let the gas out of a gas cylinder in a controlled way, lowering air pressure at each stage. The terms regulator and demand valve are often used interchangeably, but a demand valve is the part of a regulator that delivers gas to the diver's mouth in a regulator with more than one stage.

To monitor breathing gas pressure in the diving cylinder, a diving regulator usually has a high pressure hose leading to a contents gauge which can be also called a pressure gauge. The contents gauge is a pressure gauge measuring the gas pressure in the diving cylinder so the diver knows how much gas remains in the cylinder. It is also known as submersible pressure gauge or SPG.

As gas leaves the cylinder it decreases in pressure in the first stage, becoming very cold due to adiabatic expansion. Where the water temperature is less than 5°C any water inside the regulator may freeze, preventing the valve closing, causing a free-flow that can empty a full cylinder within a minute or two. Generally the water that freezes is in the ambient pressure chamber around a spring that keeps the valve open and not in moisture in the dry breathing gas from the cylinder.

The modern trend of using more plastics, instead of metals, within the regulators encourages freezing because it insulates the inside of a cold regulator from the warmer surrounding water. Environmental sealing of the ambient pressure chamber and Teflon coatings around springs are used to reduce the risk of freezing inside the regulator.

When the diver tries to breathe in, the inhalation lowers the pressure inside the chamber, which moves the diaphragm inwards operating a system of levers. This operates against the closing spring and lifts the valve off its seat, opening the valve and releasing gas into the chamber.

The medium pressure gas, at about 10 bar/140 psi over ambient pressure, expands, reducing its pressure to ambient pressure, blowing out any water in the chamber and supplying the diver with gas to breathe. When the chamber is full and the lowering of pressure has been reversed, the diaphragm expands outwards to its normal position to close the medium pressure valve when the diver stops breathing in.

When the diver exhales, one-way valves, made from a flexible and air-tight material, flex outwards under the pressure of the exhalation allowing gas to escape from the chamber. They close making a seal when the exhalation stops and the pressure inside the chamber reduces to ambient pressure.