Which Argon System?
| Cylinder Boots | ||
Argon suit inflation systems are used with dry suits in colder climes or when using breathing gases which include Helium. Helium readily transmits heat away from the body; in fact it is six times more conductive than air, using a helium mix for suit inflation risks hypothermia and mental impairment due to the debilitating effects of cold on the body.
Argon can be used to increase thermal protection by up to 40%, compared to air. It is widely available and is the gas of choice for this purpose.
 |
Argon cylinders must be visibly marked to indicate that they contain argon and not breathing gas. Inadvertantly breathing argon can lead to unconsciousness and DEATH! |
Whilst an Argon system is essential when using trimix, it may not always be necessary if you are simply getting cold and using mixtures containing only nitrogen and oxygen...whilst buying yourself some "New Toys" may seem attractive, first look at your undersuit and thermal underwear. Make sure that the garments still offer the full protection that they should and are the best you can get for that purpose. Garments DO age and are superceded by new technologies...there may be no reason to add additional clutter to your rig. See Which Suits? Under Suits for further information
Argon cylinders come in a variety of sizes, the most common being 1.0 and 1.5 litres, 2.0 litre cylinders are also occasionally found. Aluminium cylinders usually have a fill pressure of 200 bar. The choice of cylinder will largely depend on the depth and profile of dives since this will determine how much gas and how frequently it is needed to inflate your suit.
Generally speaking, you can be sure of getting 4-6 dives out of a 1.5 litre cylinder, this assumes a relatively square profile, with dives in the 0-60m range, but will heavily depend on how much gas you use.
1.0 and 1.5 litre cylinders are typically aluminium, 2.0 litres steel. Where you vary the use of an argon system depending on the complexity of a dive and gases used, it may be preferable to us an aluminium bottle since adding or removing it would have a minimal effect on your weighting compared to a steel bottle.
Since the cylinder is to be inverted and presumably on the left hand side, see below, right handed pillar valves are like to represent the best choice. (Right handed means that the handle will be on the right hand side with the tank valve upwards and the valve orifice facing directly away from you.)
There is nothing to be gained from boots for Argon systems particulary considering the risks of corrosion. See "Which Tanks? Single Cylinders".
Argon regulators consist of a first stage, low pressure dry suit inflation hose and an over-pressure relief valve (OPV).
First stages should be fairly robust and function well at low intermediate pressures. Generally cheaper first stages can be used, since they don't necessarily need to be balanced. Argon regulators have to be fitted with an OPV since there is no second stage through which gas can freeflow in the event of a failure. Some Poseidon first stages incorporate an OPV and may represent a tidy (if more expensive) way of including one.
The length of hose needed can vary widely dependent on the length of torso.
There is really no need for a gauge on an argon system since you are not likely to check it during a dive and it represents something else which may go wrong during a dive. To check the pressure you can simply attach a regulator with a gauge before the dive, read the pressure, before removing it and attaching the proper argon regulator.
If you really "have to" use a gauge since you feel you may not otherwise properly check it, you could use a button gauge, which should be fairly discreet.
It is a good idea to use so-called "tactile handles" with argon set-ups, particularly due to their exposed nature, which may result in more knocks than you might otherwise expect.
There are two types of main equipment configuration, both involve the bottle being inverted to facilitate easier access to the valve than would be the case if the pillar valve were upwards. These are:
Wreck Style: the bottle is inverted and mounted with a loop of webbing on the harness left hand waist strap in the lee of the shoulder, to minimise the drag and the chances of it becoming entangled on something (eg fishing line). It can be easily slid off if necessary to clear any entanglements.
Cave Style: the bottle is again inverted and mounted on the left hand side of the back gas tank(s). Because it is proud of your profile, it creates additional drag and is more inclined to become entangled in line which may in particular get caught in the gap between the main tank(s)and argon tank. It also means that the diver may be more prone to key-holing, this is where the diver can swim into a hole one way but not out again. For these reasons, it is imperative that the diver be able to remove and replace the argon bottle whilst wearing the set. Double cam-band systems and metal bracket mounting systems may not be as easy to remove as might be anticipated whilst wearing the set and a velcro strap system similar to that available from Hacyon may be preferable.
The 1.0 and 1.5 litres aluminium bottles can be mounted either way. Steel 2.0 litre bottles normally have to be mounted cave style due to the additional weight.
|
Ensure that you "really" need an argon cylinder and that isn't just another toy before you buy one. The first step if you get cold should be to upgrade your undersuit and only then to consider an argon system. The choice of cylinder is going to largely depend on the profile and duration of dives you do. A 1.5 litre aluminium cylinder may represent the best choice where you are unsure of easy access to argon refills, since it will likely suffice for at least a weekend's diving. Use a right handed DIN "MDE" or Scubapro Pillar valve with a tactile handle. A reasonable first stage would be something like the Scubapro Mk2, with an appropriate length low pressure hose and an over pressure relief valve. Unless there is a very good reason to "Cave Mount" your argon system, you may be better off "Wreck Mounting" it, since it avoids all the associated disadvantages. |
 |
Diving can be a hazardous sport and the information contained within this site is not intended to replace formal training.
Furthermore no responsibility will be accepted for any accidents, injuries or financial disadvantage, howsoever caused.
Copyright © H Beasley 01 August 2001 All Rights Reserved
