The Dive Cylinder or Diving Tank

These life-supporting high pressure aluminum or steel air containers hold varying capacities of air from 8 to 15 litres, and are a vital piece of scuba diving equipment.

Tanks and valves go hand in hand. The valve is the outlet from the tank, made from chrome plated glass. You will often hear of reference to the rubber O-ring, a seal protecting the valve without which you cannot dive. Oxygen rich gasses are stored Halocarbon O-rings to reduce fire risk.

The cylinder itself can be divided up into the following sections:

The Pillar Valve

The pressure valve is where the scuba diving regulator connects to the pressure vessel. It controls the flow of air and has a failsafe option known as a burst disk acting as a fuse that will fail before the vessel with increased pressure.

The Pillar Valve

The pillar valve is divided into three sections: A clamp, 232 bar Din and 300 bar DIN fitting With a pressure rating of 232 bar as with the A-clamp, the DIN fitting. The valves are to become requirements for all Nitrox equipment in order to impact the implementation of oxygen clean procedures.

The pressure vessel is usually made of aluminum or steel. Aluminum made tanks aren’t as durable but are however a lot more buoyant. They can be found at tropical dive resorts and in technical diving use whereas the steel ones are favored for colder climes.

Technical divers will use varying gasses according to their needs. Helium-based tanks provide air at depths. A cylinder for decompression stops as well as nitrox.

Y Pillar Valves

Y pillar valves incorporate a splitter into which two regulators are fed through its valves and designed that one closes in the event of a failure.

Unless recreational such as coral reef diving, during decompression diving an extra aqualung is usually carried for the purpose of a safety reserve. Decompression stops aren’t the only emergency situations, the rule of thirds are applied; safety reserve, for the journey, and a third for the return.

The risks involved usually dictate the equipment requirements for example ‘direct ascent impediments’ such as overhead obstructions technical dives. Regulators and tanks are also combined into a for open circuit divers. The most common include the single cylinder with an octo not recommended for diving deeper than 30m, for decompression stops or technical dives such as wreck diving, cave diving, or ice diving. An emergency situation will arise however if the first stage fails and the sharing/buddy system will need to be relied on.

Small independent cylinders known as ‘ponies’ ( 2- 5 L capacity) which do not compromise buoyancy and are clipped to the BC. Shallower water emergencies make use of the hand-held mini aqualung.

Technical divers make use of two separate cylinders requiring a change of demand valves while diving. This problem can be overcome with a twin set joined at their pillar valves.

Cylinder Care

Ensure that you refill your tank at a well-respected air fill station. They are never filled with pure oxygen but compressed air for breathing.

It’s important to be aware that tanks must never be left standing upright and unattended as they roll and can hurt someone or damage equipment. Accidents do happen, so plastic and rubber fittings should be present to assist in extra protection. Most dive boats have special racks and if you are on land, it is advisable to tie them down or secure them carefully.

Make sure the tank isn't leaking air, as this can be highly corrosive. Keep moisture out of it at all costs and avoid leaving it in the sun. Ensure that your tank is inspected regularly and that it undergoes all the necessary tests and maintenance to ensure peak performance.

A component of the Aqua lung, the cylinder is used by the diver to access high pressure air through the demand valve of their diving regulator. The scuba diving tanks are also used on land for purposes other scuba namely storing oxygen in cases or first aid emergencies as well as basic storage for the compressed air.

Diving compressors should be the only source for tank fills or breathing gasses made with specialized gas blending techniques. It is imperative to ensure that cylinders are filled with reputable dive shops and suppliers offer these services as breathing irregularly mixed gasses can be very dangerous hence the system of labeling gas ratios and cylinder colour coding. As one descends, the compressed air changes chemically and lethal infectivity can arise. Externally gas explosions can occur due to incorrect proportions and cylinders made from weaker materials such as aluminum as well as improper maintenance and corrosion.

When dealing with oxygen keep in mind that the gas should be kept stored in tanks specified implicitly for oxygen usage and that high concentrations cause rust and fire. Highly pressurized cylinders reduce the risk of bacterial and other contamination.

Hydrostatic tests are commonly applied in order to ensure standards by measuring a tank’s volume before and after undergoing test pressure. It is highly advisable to familiarize yourself with Gas Cylinder Colour Coding to denote various air content types, as well as the standards applied by different countries.