SWIM REGULATORS 65 Performance Many people believe performance is the major criteria in the choice of a regulator. Certainly, you should choose a regulator that is appropriate for the types of diving you intend to undertake. Most modern regulators will perform adequately under normal demand at moderate depths. The deeper you dive and the harder you breathe (for example, swimming against a current at depth) will result in a higher demand on your regulator. So if you were planning on diving in demanding conditions, it would pay to invest in a high-performance regulator. Generally though, when it comes to judging performance, it pays to remember that the greatest testament to a regulator is its performance under harsh environments. Australia’s Far North Queensland (FNQ) has the highest concentration of dive equipment usage in the world. Gear may be used three to four times a day, seven days a week. These professional operators recognise the need for the best equipment. They also understand that the materials used and the design are critical for their customer’s ultimate safety and comfort. Aqualung regulators have proved to be the most popular choice in FNQ and resorts around the world. Unlike Aqua Lung, very few companies make their own regulators. Most equipment suppliers outsource products or simply re-badge or assemble components from existing manufacturers. This makes quality control very difficult and encourages Scuba regulators are designed to reduce the high-pressure air from the scuba cylinder obsolescence. Suppliers will move from one manufacturer to another as either the to a level where the diver can breathe comfortably and safely. Jacques Cousteau and manufacturer is unable to supply the parts, or the supplier finds a cheaper alternative. Emile Gagnan developed the original regulator, the aqua lung. It was a twin-hose Aqua Lung is owned by Air Liquide, one of the largest gas-control companies in the system that reduced the pressure in a single stage connected to a cylinder. world. In fact, Cousteau took his original concept to Air Liquide over 50 years ago and it These days, regulators are a single-hose design and the pressure is reduced in two was an Air Liquide engineer, Emile Gagnan, who helped develop and build the first scuba stages. The first stage reduces pressure from the cylinder down to near 10 bar, then regulator. Today Aqua Lung builds more regulators than any other company in the world. the second stage delivers air on demand. (That’s why the second stage is sometimes called the demand valve.) Your regulator is the most important component of your diving equipment. It delivers the air you need to breathe. It is your life-support system. By reading through the selection criteria here and matching the features you require in How to Measure Performance the following pages you will be able to make an informed decision. Before you can establish the level of performance required, you must first understand Service and Parts how performance is measured. Many different tests are quoted as a bench-mark level, The single most important factor when choosing a regulator is the ability to obtain but the most widely regarded is the US Navy test. It involves both manned and regular, professional maintenance and spares. Ultimately, this will have more effect on unmanned tests of regulator performance. your regulator’s overall performance than any other factor. As your diving experience grows you’ll want to discover new and exciting places to dive The US Navy set 1.4-joules effort as the maximum inhalation effort. In order to qualify all over the world. for the top level, category A, the regulator needs to meet these criteria at 62m at Your regulator must be able to be serviced wherever you will be diving, whether that’s moderately heavy work rates. In the last test performed by the US Navy only six sport the Barrier Reef, Papua New Guinea or Belize. diving regulators qualified as category A. With so many regulators on the market it is impossible for the average dive store to carry parts for every regulator. Understandably, they will restrict their parts inventory to Two models were from Aqua Lung, the US Divers SE2 and the US Divers Pro Diver. the more popular brands. Also, it’s unlikely that the average regulator technician will be These same two regulators came first and second respectively in the manned tests. qualified to service every regulator on the market. The first brand almost every These models have since been improved with the advent of the Titan and Legend series technician learns to service is Aqualung. from Aqua Lung. Aqualung was the first regulator ever made and it is still the most popular brand in the world today. No matter where you go in the world you will find parts and service are Some divers have performance needs that go beyond the realm of the typical sport available. diver. The most popular brand for this diving category is Apeks. That’s one of the reasons why more military forces around the world choose Aqualung The latest regulators from Apeks have recorded less than 1.03-joules inhalation effort than any other brand. at 80 m (Remember, the US Navy class A is 1.4j at 62m). This demonstrates effortless breathing at extreme depths. The Apeks ATX200 is widely regarded as the best performing regulator in the world. 2004 AQUANAUT GUIDE SCUBA REGULATORS 67 Adjustability Environmental Seal There are two primary adjustments available on modern regulators. One type of In order to keep a consistent flow of air at depth your regulator needs to sense changes adjustment will alter the positive flow of air. This is often called the venturi. A regulator in depth. This is achieved in most regulators by allowing the regulator spring chamber with an effective venturi will generally breathe well, but may free-flow when not in the to flood with water. Diaphragm style regulators achieve this through limited ingress of diver’s mouth. A venturi adjustment is very important as this allows for maximum air water, typical piston designs flood completely. Unfortunately when water completely delivery when required with a minimum switch to prevent free-flow. floods through your regulator it carries with it damaging contaminants that will reduce Other adjustments available on some models adjust the spring tension which controls the regulator’s performance and life-span. Many attempts have been made to seal the opening effort required. This is called the cracking resistance control (see diagram regulators; one system packed the regulator with oil, while another involved a above). This allows the regulator to be adjusted to minimise breathing effort under all continuous release of bubbles to keep the water out. conditions. The most effective system is the patented Dry Sealed System, which is available as an option on Aqua Lung regulators and standard on most models of Apeks regulators and Lever high end Aqua Lung models. Venturi adjustment knob The patented dry seal system stops water entering the regulator Cracking resistance control Internal diaphragm External diaphragm Pneumatically balanced valve system Diaphragm Venturi Adjustment Aqualung considers the adjustable venturi so important that, while most manufacturers reserve this feature for high-end products, every Aqualung regulator has this control. switch in positive position, where the Important Considerations venturi vane directs air into the mouthpiece switch in negative position prevents and ensures minimum breathing effort even freeflow of air under stressful conditions There are two other factors to consider when choosing a regulator.The first is to ensure that your regulator has sufficient ports to accommodate all attachments. You need at least one high-pressure port for your gauge and you may want a second high pressure port for a second back-up gauge. In addition to your primary 2nd stage port you will need three more low pressure ports for an octopus, BCD hose and possibly a drysuit inflator hose. The quantity and positioning of ports allow you to configure your regulator for maximum comfort. Finally, comfort of the mouthpiece is very important, as is the ability to change a mouthpiece should it become worn or damaged. The world’s best mouthpiece is the Comfo-bite. SCUBA REGULATORS 69 Balanced Second Stage High Performance Many companies claim to have a balanced regulator but all they are referring to is the first stage. The world’s best performing regulators also have a balanced second stage. Regulator Features A traditional second stage has a valve spring strong enough to hold back all the pressure from the first stage. This spring pushes against the seating mechanism to Balanced First Stage stop the air-flow until the diver breathes. When the diver breathes the diaphragm is A balanced first stage has a ‘balancing chamber’ which ensures that as tank pressure pulled forward against the lever, which in turn compresses the spring and pulls back drops the pressure of air to the second stage is maintained. the seat to allow the air to flow. This allows the regulator to breathe easy even at low tank pressures. A balanced second stage allows air to pass through the centre of the poppet valve to a counter-balance cylinder, which assists the spring in closing the valve. This reduces Overbalanced First Stage the need for a heavier valve spring, which cuts down the effort needed to compress the As the diver gets deeper the air they breath is compressed and therefore more air spring which in turn makes inhalation very easy. A balanced second stage is therefore is needed to fill the diver’s lungs. This is a basic principal taught in the beginner’s highly desirable.