The scuba diving mouthpiece is referred to by two different names - the regulator and the demand valve. It is an essential piece of equipment for anyone who is scuba diving.
The reason this piece of equipment is so vital is that it controls how you breathe and the pressure of the breathing gas you use when you are diving. This ensures you have adequate levels of it to stay alive under the water.
Typically you may find that the job of the regulator (or demand valve if you prefer to call it that) is to reduce the pressurized breathing gas down to ambient pressure. This is then delivered to the diver.
The pressure can change as you breathe. This is because the pressure gets reduced when you inhale so that the regulator can give you the air you need. It works in two stages. Let’s explore how it works in more detail…
In the first stage, the air is passed through two air chambers that are separated by a valve. When the regulator of your mouthpiece is pressurized, the air passes through the open valve at high pressure to the second chamber. In the second chamber, it gets to an intermediate pressure of around 8 to 11 bars.
When you breathe the air during the second stage, the air gets released from the valve at a safe pressure for breathing. This only happens when you physically inhale. The pressure of the air changes from 8 to 11 bars to ambient pressure.