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Your complete guide to Scuba TanksScuba Tanks are those big ungainly metal things that are strapped to scuba divers backs. They are so important that without them you cannot go scuba diving. So no scuba tanks, no scuba diving. What is a Scuba Tank?
A scuba tank is a big metal container, the shape of a cylinder and is designed to store air under pressure, so we can breathe underwater. As simple as that.They come in a variety of sizes and there is one designed for everyone, because everyone is different, some people are small and have a more economical breathing rate whilst other people are larger and chew through there air faster. One size does not necessarily fit all. The scuba tank has a threaded neck which allows for a control valve. The control valve is the mechanism that allows air to flow in and out of the scuba tank. Scuba Tank ValvesYou have the choice of three scuba tank valves for single tanks;
The K-Valve is the most popular scuba tank valve and is a simple on-off valve, which you will find on most hire scuba tanks. Your regulator attaches to the scuba tank via the K-Valve on the neck of the tank. The regulator attaches to the O-Ring. The O-Ring looks like a rubber washer and enables the regulator to form an air tight seal with the tank valve. The K-Valve is what we call a Yoke Valvea Yoke is basically an oval metal loop with a screw opposite the regulator that clamps it to the tank valve. This is the same for J-Valves as well.
It is very rare to see J-Valves and I would be surprised if you came across any that were for hire. The J-Valve had a spring mechanism built in that would stop the air flowing once a certain pressure was reached. It was used as a reserve, the remaining air in the scuba tank could be accessed by pulling down on the J-Valve which would allow the remaining air to flow. These days we have Submersible Pressure Gauges to tell has how much air pressure is left in our tanks.
A DIN Valve is used on High Pressure Tanks, scuba tanks with pressure ratings over 3,500 PSI. A DIN Valve needs the regulator to screw into the Tank Valve to seal. The DIN kind of looks like a big bolt with a hole in it, the hole is threaded and your regulator needs to screws into it. At the end of the thread is an O-Ring which provides the air tight seal between the regulator and the DIN Valve. You can get adaptors that let you interchange between K-Valve yoke fittings and DIN Valves. O-RingsWithout an O-Ring you would be unable to provide a seal between the Scuba Tank Valve and your regulator. Wait a minute, yes you would be able to provide a seal, however the seal would not be air tight.The O-Ring can wear over time, chips and tears are common and the O-Ring will need to be replaced. Always carry spare O-Rings, if it falls out during transporting your tank to your dive site and you do not have a replacement, then forget about diving. When you use hire tanks, make sure you check the O-Ring to ensure it does not have any tears, hire equipment can be a little run down at times. Types of Scuba TanksThere are effectively two types of scuba tanks.1. Aluminium Scuba Tanks 2. Steel Scuba Tanks There are pros and cons for both and each diver has his or her preference. For a complete review have a look here for aluminium tanks and here for steel scuba tanks. Scuba Tank MarkingsYou will note on the shoulder of your scuba tank, a lot of numbers and letters. These tank markings are very important they tell you information about your scuba tank.Click here to find out exactly what all the markings on your scuba tank mean. Choosing a Scuba TankIt is never easy deciding which scuba tank is for, there are so many options. remember one thing though, if all your diving will be with a dive shop and you are comfortable using the Aluminum 80's, then don't buy a scuba cylinder.If on the other hand you find the Aluminum 80's too big and arkward or you are doing a lot of shore diving, then have a look here at the various scuba tank sizes. Scuba Tank InspectionThere are two types of inspections performed on scuba tanks and depending on what country you live in will determine it's frequency.The Visual inspection is only carried out in the US annually, whilst the Hydrostatic test is conducted every five years in the US, but in Australia it is done every year.
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