How Does a Scuba Tank Work?
Scuba is an acronym for Self Contained Underwater Breathing Apparatus. It is also sometimes called an Aqua Lung because it operates in much the same way as a human lung. Humans have wanted to swim with the fishes for as long as they have been around, and many different methods for underwater diving have been explored over the years. In 1943 the Scuba Tank or Aqua Lung was invented by Jacques Cousteau, and enabled humans to breathe while underwater. Previous methods such as diving bells and piping air to divers had been cumbersome but now with the Aqua Lung, movement became easier as the tanks operated like an external lung that went where the diver went, eliminating the need for restrictive pipes and hoses.
Scuba tanks usually contain normal air which is a mixture of nitrogen and oxygen and there is roughly enough air in one tank to safely dive for an hour. Some configurations of scuba tanks have more than one tank and this will facilitate longer diving time, although it is not recommended that divers spend too much time underwater because of pressure issues. The tanks are usually made of aluminum and sometimes steel and they store the air pressurized to 200 to 300 atmospheres. This allows each diver to have his or her own supply of air. The flow of air from the tank to a divers lungs is facilitated by a regulator which is connected to the top of the scuba tank. The regulator has a two-fold purpose. It reduces the air in the tank to a pressure less than the water pressure at the diver’s depth. This is done by the section of the regulator, sometimes nicknamed an “octopus,” or first stage or the regulator which is screwed onto the top of the tank.
The next section of the regulator is that part that is put into the mouth by the diver and this is called the second stage of demand valve or the regulator. Connected to the hoses which protrude from the regulator are gauges and instruments which enable the diver to monitor air supply and depth during the dive. The air in the tank is under pressure and as a diver inhales, the second stage of the regulator releases the air under pressure into the mouth allowing breathing under water. When the diver exhales, the valve in the regulator works to block new air from the tank and opens another valve to release the exhaled air into the water. Then as the diver inhales again the valves work in the opposite fashion to allow air to once again be taken into the diver’s lungs.
Normal air is used in scuba tanks to most usual depths, however if one needs to go to greater depths a scuba tank containing other breathing mixtures with a different concentration of oxygen will be employed. Scuba divers need to be qualified before they can dive and this requires a training course of a few days. If the diver wants to dive to 30 ft. then an Open Water license will suffice. To go to 100 ft. one needs an Advanced Open Water License. To go deeper one can qualify for Nitrous or other diving licenses. No matter which type of scuba tank a diver uses they all basically work the same way, that is by mimicking the human lung to provide breathable air at a suitable pressure under the water.