Scuba Tanks
In order to overcome the limitations of the human body divers carrying scuba tanks to provide a breathing gas at ambient pressure.
Scuba tanks are also known as cylinders or bottles and normally in recreational diving the breathing gas is air.
Some non-divers will refer to the tanks as oxygen tanks or bottles, but this is incorrect - oxygen is toxic when breathed in high concentration at depth and so pure oxygen is never used in recreational diving.
The cylinders are almost always manufactured from either steel or aluminum, with the latter having the advantage of being more resistant to corrosion.
While the original material is steel, which is used widely throughout Europe, it is common to encounter aluminium tanks in the United States and the Caribbean.
Aluminum scuba tanks do suffer some disadvantages though - as it is softer than steel it is more likely to suffer damage with rough or careless handling, and because the walls need to be thicker the tanks are larger and heaver compared with a comparable steel tank.
However, when the tank suffers corrosion internally the layer of oxide inhibits further corrosion, protecting the tank - in a steel tank this is not the case.
Usually worn on the divers back, a scuba tank is attached to the Buoyancy Control Device (BCD), or jacket, and to the top of the cylinder is attached the first stage regulator.
The main connector for the first stage is the A-clamp, but a less frequently seen option from Europe is the DIN connector - the latter provides a firmer seal than the A-clamp.
The first stage regulator provides air to the BCD - air is introduced or expelled by the diver to ensure neutral buoyancy, which varies by depth - as well as the air gauge, which these days is often incorporated into a diving computer.
It also provides air to the second stage regulator at an intermediate pressure, which is reduced by the second stage to ambient pressure to enable the dive to breathe.
Standard configuration for the second stage in modern dive equipment is in the same housing as the mouthpiece.
Scuba tanks are also known as cylinders or bottles and normally in recreational diving the breathing gas is air.
Some non-divers will refer to the tanks as oxygen tanks or bottles, but this is incorrect - oxygen is toxic when breathed in high concentration at depth and so pure oxygen is never used in recreational diving.
The cylinders are almost always manufactured from either steel or aluminum, with the latter having the advantage of being more resistant to corrosion.
While the original material is steel, which is used widely throughout Europe, it is common to encounter aluminium tanks in the United States and the Caribbean.
Aluminum scuba tanks do suffer some disadvantages though - as it is softer than steel it is more likely to suffer damage with rough or careless handling, and because the walls need to be thicker the tanks are larger and heaver compared with a comparable steel tank.
However, when the tank suffers corrosion internally the layer of oxide inhibits further corrosion, protecting the tank - in a steel tank this is not the case.
Usually worn on the divers back, a scuba tank is attached to the Buoyancy Control Device (BCD), or jacket, and to the top of the cylinder is attached the first stage regulator.
The main connector for the first stage is the A-clamp, but a less frequently seen option from Europe is the DIN connector - the latter provides a firmer seal than the A-clamp.
The first stage regulator provides air to the BCD - air is introduced or expelled by the diver to ensure neutral buoyancy, which varies by depth - as well as the air gauge, which these days is often incorporated into a diving computer.
It also provides air to the second stage regulator at an intermediate pressure, which is reduced by the second stage to ambient pressure to enable the dive to breathe.
Standard configuration for the second stage in modern dive equipment is in the same housing as the mouthpiece.
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