SCUBA GEAR

Regulators (1st Stage & Demand Valves)

The regulator is one of the most important parts of your scuba equipment. For this reason your regulator should be chosen and maintained with care. When choosing a regulator for use in the sometimes-cold water of the UK you should look for one that is tried & tested and is 'cold water rated'. A regulator is essentially in two parts:

The First Stage - this connects to the cylinder using an A-clamp or DIN fitting, (see comparison below). The purpose of the 1st stage is to reduce the very high pressure from the cylinder to a moderate pressure (8 to 10 bar above ambient pressure) that may pass through a flexible hose to your mouthpiece (called the Second Stage or Demand Valve).

The Second Stage or Demand Valve (DV)- this is the regulator that you breathe from. The DV is another pressure reduction valve that reduces the pressure of 8/10 bar above ambient to "ambient pressure" and supplies air on demand - that's why it's also called a 'demand valve'.
Octopus- an octopus is just a 2nd DV used as a backup by either you or your buddy, usually coloured yellow for easy location

A-Clamp or DIN? -
There are two types of fitting to connect a regulators to a cylinder used in the UK - they are called "A-Clamp" & "DIN",

A-Clamp - Is a very popular fitting in the UK, simple and easy to use, Max. 232 bar, O-Ring is housed on cylinder and thus has the risk that it may be more easily damaged or lost.
DIN - Safer and more secure with an enclosed O-Ring seal, can be fitted to a 300 bar cylinder.
Cross Compatibility - DIN fittings can be used on an A-Clamp type cylinder using an adapter (bought for about £15). Newer A-Clamp cylinders may be adapted to DIN by removing a fitting from within the pillar valve. A-Clamp can be fitted to DIN type cylinders using an adapter but only to a Max 232bar, A-Clamp cannot be used on a 300 bar cylinder.
* My opinion - A-Clamp is fine & widely used, Check out & ask about other divers regulators & choose 1 that appeals , Apex is a good UK manufacturer,

Consoles & Gauges
A console may house one or a series of gauges. The console is attached to the first stage regulator by means of an air hose; this hose enables the contents gauge to provide a reading of the cylinder pressure. A typical triple consoles may house a contents gauge, a depth gauge and a compass to enable underwater navigation.
* My opinions - look around at other divers equipment, a "bottom timer" is more useful than a simple depth gauge.

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