You need one, unless you can breathe air pressurized to 3000 lbs, okay?
So you're wondering how you even found yourself here in this technical backwater, and you're thinking, what are you doing here Hedge? No one wants to even think about their first-stage regulator, let alone read about 'em, or worse, write about 'em. Get a life!
Don't we both have some diving to do?
True enough - I'd really rather be diving! But without a reliable, functional and durable first stage, none of us is going to do any diving at all. That is, unless we want to do that breath-hold type of diving. But that's not what y'all had in mind, is it? So, let's take a look at this underappreciated workhorse piece of SCUBA apparatus and come away with a new-found appreciation and love for the First Stage Regulator.
What is a First Stage anyway?
The first thing you should know about your first stage regulator is that it isn't the second stage regulator! Your first stage is the metal doohickey that attaches to the valve atop your air tank, reducing the high air pressure down to an intermediate pressure that your second stage regulator (the other doohickey that you actually stick into your mouth and breathe into and out of) can manage. The two work together to regulate the airflow from your tank and are both absolutely necessary - but for some reason, the second stage regulator gets all the attention. Divers do a lot of handling of/kissing on the second stage; but if your first stage is working correctly, you don't ever even have to think about it, let alone give it a smooch after a dive well done (something I suggest should be a regular part of your diving routine).
Types of First Stages
There are really only four first stage designs. The working mechanism is either a Diaphragm or Piston, and these two are broken down into a Balanced or Unbalanced variety:
• Unbalanced Diaphragm is an anachronistic design, and these types of regulators aren't manufactured today.
• Balanced Diaphragm first stages involve an additional low-pressure air chamber in their design (the balancing chamber, hence the name) and therefore incorporate more moving parts than Piston-type first stages. Their moving parts are protected from water and the elements, however. The technical complexities required to manufacture and service Balanced diaphragm regulators make them more expensive to buy and maintain than piston-types. Also, there's the old axiom Murphy coined about the more moving parts, the more that can break down...
• Unbalanced Piston first stages are commonly used - pick up a reg unit at any dive school, and chances are you'll be holding an unbalanced piston-type. They're cheap, but have limitations; the moving parts come in direct contact with water and water-borne crud, they are unable to handle high pressures, and they deliver a varying hose pressure to the second-stage regulator.
• Balanced Piston-types are the most widely manufactured first stage regulators. They are able to withstand high pressures, and deliver constant hose pressure to the second stage. As you might guess, they are also generally more expensive. Like unbalanced pistons, their moving parts contact water and sediment.
How to Compare First Stages
Some manufacturers have priced their regulators so that there is a markup when buying first and second stages separately, so if you're concerned about price, look to buy a complete set up: first and second stage, hoses and attachments, and, quite probably if you have the means, an integrated computer console with depth and pressure gauges, and maybe a compass. A look at the entirety of regulator systems is beyond the scope of what I've attempted here (remember, we're both just a little lost, right?).
Even if you're buying an integrated system, take a close look at the included first stage and consider the following:
Look to buy a Piston-type regulator (I hope that you see that choosing a piston-type is the obvious way to go based on the above information), rather than a Diaphragm-type regulator. Generally, if you're half-fish and doing more advanced diving, you'll want a Balanced piston; if you're merely all-human and a recreational diver, opt for an Unbalanced piston.
Some regulator models are equipped with a environmental exclusion setup (usually a malleable silicone sealant) that works to prevent water and crud from entering the first stage. While protective, these setups effect the regulator's responsiveness, and are usually only used as a precaution against ice-up during cold water diving. If you don't do any really chilly dives, this is an extra you can do without.
Finally, take into account the regulator's composition. Most first stages are made of chrome-plated brass. A better option is to buy one made of stainless steel, which is much more durable than brass. The best route, and, of course most expensive, is to buy a titanium-plated rig with titanium parts. Most divers should simply buy chrome-plated, inspecting the regulator for uniform-thickness of chrome plating before making the purchase. Advanced divers will want to consider first stages made from the tougher, more expensive materials.
No comments:
Post a Comment