(01-07-10) First article of the three dedicated to how to take care of the compressed air tank and the need to have it always ready, by Marcelo Pierini.
In this first article we will learn something about the diving technique we do not pay much attention: the maintenance and cleaning of our tanks. We breathe through them in water, and their care and control are basic.
Nowadays, we tend to have our equipment in perfect conditions, although it is a bit boring. In our Schools and Dive Centres we encourage practices to maintain all the equipments, sportive or technique, in conditions enough not to have a problem of this kind in the following dive.
For example, when our lives depend on an autonomous, it is very important to follow the instructions of the maker to have reliable equipment, with a perfect working and that meets all the specifications. So, it is extremely important to listen to those who, for example in shops, suggest us some secrets for the maintenance.
Many of us use to clean and have the BCD in good conditions, washing it with fresh water, let some air in the bladder, revise the valves, disarm and lubricate them, check the hoses, the trachea and triggers inflation and deflation.
Review that there is not a hole and hung them in a place out of Light sun and dry if it is possible. Id we go to dive to the sea, much more. With that we assure that when we come back to use it, everything will be ok. We also have to check the glasses and the tube, not to have them broken, or filtering, and that the fastening strips are not cracked or dried, since we are going to have a problem for sure if they are.
Wet suits must be washed in fresh water and neutral soap. Let them get dry in the shadow, both sides, and then hang them in a place were sun cannot reach them. If they are suits of a school, use an antibacterial and proceed to the subsequent rinse. If they are dry suits, rinse them in fresh water, wearing them if it is possible, or later.
Valves, sleeves and neck must be verified, as well as watertight closures. They must be in perfect conditions. There are some commercial products for their maintenance, but also we can pass through the rack a candle and open and close it several times to detect that it opens and closes very well. With the gloves, hook and boots will proceed like with the wet suit.
We use to think that the regulator is indestructible, but is not. We should revise them regularly to guarantee it works properly, during all it lifetime. With computers, cameras, knives, lanterns and other accessories, rinse them with fresh water and let them dry in the shadow.
As you see, we all know how to have all equipment in good conditions. But, as you have seen, I have not talk about tanks. Why? Because we think that just loading them is enough, maybe a protective mesh to avoid scratching the paint and a boot which support and nothing else.
Maybe because one can think that tanks do not need as much care as the rest of the equipment: error. It does need it. Through it life comes: the air you breathe. We have to take care of it and keep it in perfect conditions.
Many times we take care of the compressor, but regarding tanks… when? Well, this article is about it: the care and maintenance of the cylinders.
Compressed air tanks used in diving have different names: tank, bottle, cylinder, in Argentina "cilindro", in Spain "botella"...
A tank is a cylindrical metal container used to contain a high pressure gas to breathe underwater. They are of different air capacities, depending on pressure and size. In the metric system capacity is said in litres or kilograms of air. They can be from 4 to 18 litres, depending on the person and the kind of diving. In the imperial system, capacity is expressed in cubic feet of air. The most common sizes are 50, 71.2 and 80 cubic feet.
Cylinders we commonly use are those of 12 litres (80 feet) and common pressures are between 170 and 200 bar(1,013 bar = 1 Atm), or from 2250 to 3000 psi. (Pounds Square Inch). Nowadays there a lot of products made of different companies, of different materials and capacities, according to the user needs.
Basically, we can identify two materials in them: steel (steel alloy, chromium and molybdenum) and aluminium (cheaper and lighter). They are built from a solid cylinder until they form a pipe that, at the end, forms a tank.
A mould of steel of the size of the bottle is used. Through the extrusion method, it introduces it and gives the final shape. See the following videos on You Tube:
http://www.youtube.com/watch?v=OmSvbp2NFbc
http://www.youtube.com/watch?v=EzVogfVxXPc
Some elements we must pay special attention and know how they work, for then dismantle and clean, are the following:
* Faucets: The cylinder has a single opening to which set a control and attach faucet. It consists on a valve (type “J” or “K”), a knob that controls the opening and closing of the cylinder and one or more outputs coupled to the regulator (type INT or bracket and other type DIN that holds the regulator to the bottle by a thread that supports higher pressures).
* Bursting disc: is a safety device that serves to break and let out the gas load when operating pressure exceeds the cylinder thus avoiding the explosion of it for excess pressure.
* Inspection sticker: for safety reasons, cylinders must be checked regularly. In the charging stations it must be placed a sticker certifying that it is within the inspection period and can be reloaded.
Text: Marcelo Pierini
Article 2: BASIC MAINTENANCE
Article 3: HYDROSTATIC TEST |
