ScubaScotty561
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I'm looking into getting my certification and noticed something said a 2 stage regulator and wondered what that is. thank you.
What is a 2 stage regulator?
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That is the standard type of regulator used in diving. The first stage screws into the valve on the tank and reduces the pressure from 3000 psi or so down to about 130 psi. The second stage is the part with the mouthpiece which you breath from, attached to the first stage by a flexible hose.
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In addition to modern 2 stage regulators, a 2 stage regulator can also be an old style double hose regulator. In the days when 2 hose regulators were common, there were both 1 (single) stage regulators like the US Divers Mistral and Voit 50 Fathom and 2 stage regulators like the DA Aquamaster, Royal Aquamaster and a host of others. Regardless of age, a 2 stage regulator reduces tank pressure in the first stage to some lower pressure know as intermediate pressure (IP) and the second stage delivers air to the diver on demand at ambient pressure. On the other hand, a single stage regulator drops tank pressure down to ambient in one stage. There are no single stage regulators being made today although there are a lot of us who still dive them. Single stage regs were the preferred regulator of Jacques Cousteau for their simplicity and reliable operation.
In addition to modern 2 stage regulators, a 2 stage regulator can also be an old style double hose regulator. In the days when 2 hose regulators were common, there were both 1 (single) stage regulators like the US Divers Mistral and Voit 50 Fathom and 2 stage regulators like the DA Aquamaster, Royal Aquamaster and a host of others. Regardless of age, a 2 stage regulator reduces tank pressure in the first stage to some lower pressure know as intermediate pressure (IP) and the second stage delivers air to the diver on demand at ambient pressure. On the other hand, a single stage regulator drops tank pressure down to ambient in one stage. There are no single stage regulators being made today although there are a lot of us who still dive them. Single stage regs were the preferred regulator of Jacques Cousteau for their simplicity and reliable operation.
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What is standard these days is a two-stage "single hose" regulator. Of course, regs have more than two hoses, but the bare minimum number of hoses a regulator needs to work properly is one. That's the hose to the second stage--the part that you breathe from. The other three hoses (LPI, SPG, and Octo) are important, but not critical to the operation of the entire regulator.
Rongoodman and Herman are spot on describing the two stages. To expand a tad, the second stage is a demand regulator that further reduces IP to ambient pressure so the diver can breathe it and it feels normal.
Rongoodman and Herman are spot on describing the two stages. To expand a tad, the second stage is a demand regulator that further reduces IP to ambient pressure so the diver can breathe it and it feels normal.
halocline
Contributor
The first stage is a demand valve too.
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