What is a scuba regulator designed to do?

Answer 1

A Scuba regulator is designed to provide air to a diver via a demand valve system in a regulated and safe fashion.

A Scuba Regulator consists of two stages - a "first" and "second" stage. The first stage which attaches to a scuba tank by use of either a din or yoke valve, reduces the pressure of the air passing through it to an intermediate pressure slightly above the surrounding pressure at whatever depth of water the diver is at.

The part of the regulator that is in the divers mouth is called the second stage, and is a "demand valve" which gives air to the diver each time he inhales. On exhalation the valve closes and the exhaled air is released as bubbles from the exhaust ports built into the bottom of the second stage.

The fist stage of the regulator also has connections for a high pressure hose which is connected to a Pressure Gauge (showing the remaining air pressure in the scuba tank), one or two low pressure hoses to attach to the divers buoyancy control device and drysuit and an extra second stage which is used for emergency situations for use by another diver.

All regulators are designed with a fail-safe mechanism which means that if they suffer any technical problem, the regulator will "free flow" allowing the diver to return to the surface or to an alternate air supply safely.

Answer 2

The first stage of the regulator is used to reduce the pressure in the tank to roughly 150 psi over the ambient pressure. It can then be sent down a hose built to withstand that lower pressure, meaning a smaller, more flexible hose. These hoses are used to supply air to the second stage regulator, power inflators, and other air-driven devices.

The first stage assembly also has one or more high pressure ports which can be used to monitor the unreduced pressure of the tank.