- Regulators consist of a first and second stage. They are designed to take the high tank pressure and break it down to a divers demand level.
- Advances in regulator technology and materials allow for easier breathing, and less jaw fatigue.
Since there is no way a diver can breathe directly off a scuba tank, they need a regulator to take that tank's high pressure, break it down and deliver air based on the divers demand.
Generally the first stage of the regulator that attaches to the tank, takes the high pressure and breaks it down to an intermediate pressure of approximately 125-140 psi over ambient pressure. So at 33 feet it is actually giving 145psi-165psi and at 66 feet it reads 15psi higher etc. Then, the air comes out of the low pressure ports on the first stage and fills the hose line up which is connected to the second stage, where the diver's mouth-piece is located. Air is then provided on a diver demand basis. You inhale the air from the hose fills the open space in the mouthpiece and you breathe in.
In looking at the first stage of a regulator you need to consider several factors.
Most entry level regulators are unbalanced and quite a bit less expensive, whereas the next model up is generally balanced. An overbalanced first stage considered the best performing of the three delivers an increased volume of air to the diver as their depth is increased. A balanced first stage regulator offers consistent air flow regardless of depth and tank pressure. An unbalanced regulator will become harder to breathe from as depth increases and or tank pressure decreases. The state of the art version of a first stage is to have it overbalanced. As a diver descends more air is delivered, hence making the overbalanced first stage regulators the easiest to breathe for the diver.
These are two primary types of first stages. They refer to the method of reducing tank pressure to intermediate pressure. Piston first stages have fewer moving parts but are exposed to the outside elements more. They are generally less expensive to service. Diaphragm regulators have more parts but are sealed from the environment. Of course you get the right warranty the expense of repairing is negligible down to the cost of labor only.
We all know when you take the regulator out of the bag we need to inspect the first stage filter area before we put it on the tank and vice versa. We also want to prevent getting water or other contaminates in the first stage as well. Some manufacturers have a new closure that prevents contamination of the inside of the first stage.
If you are choosing to use the HP tanks because they are smaller in size, you will need to check into the available.
When diving with nitrox or enriched air, first and second stage regulators need to be cleaned and there are special materials for the activity. Some manufacturers provide the regulators nitrox or enriched air ready. Titanium regulators are not suited for any enriched air or nitrox mixes. You must take a specialty class in order to dive the enriched air nitrox mixes.
Generally there are 3-5 low pressure ports accommodating your safety second, power inflator hose and a dry suit hose if needed. Some manufacturers have first stages that all the LP ports are on a swivel, so when you turn your head the hoses follow with you. There is also one high pressure port that bypasses the regulator allowing you to read direct tank pressure at any time. Some regulators have two high pressure ports so you can put your gauge on either side or set up a backup.
Now you have the intermediate pressure on the second stage of 125psi to 140psi over ambient pressure which was explained earlier. As you inhale you pull the diaphragm back which moves a lever that is spring loaded and releases a rubber seat off of a cone allowing air to flow into the mouthpiece.
This information copyrighted by Chris Fuller.