Scuba Diving Regulator

This device typically provides regular air flow when you inhale from the pressurized air supply in your diving tank. It consists of what is referred to as two stages, the first being the mechanism that connects the various other hoses to the tank and the second stage is the mouthpiece. The function of a regulator is to control the release of the pressurized gas from the cylinder in accordance with the diver's depth requirements and is not to be confused with the demand valve. Ensure when cleaning all pieces of equipment for maintenance after a dive that you are well versed with regards to the needs of each piece, as they vary in methods required for optimal care. The regulator first stage functions as a constant gas pressure release monitor reducing the gas to around 150 psi from around 3500psi. Two most common types are Diaphragm and Piston types regulators.

Due to adiabatic expansion - a process rooted in the principles of thermodynamics (simply termed 'the power of heat') where there is a lack of heat present in the fluid transfer , regulators run the risk of becoming blocked with ice. The mechanisms that dictate the valve functions are targeted causing the water inside the regulator to freeze at anything below 5 degrees. Special Teflon coatings and proper external protection and sealing can prevent this.

A typical regulator has the following features:
• An exhaust valve to control in and outgoing airflow in accordance with your breathing requirements. Open circuit scuba gear typically has and A-clamp or Yoke which connects the cylinder outlet to the actual regulator and is pressurized with an O-ring.
• The mouthpiece through which the air is inhaled. This is also equipped with a purge button for manual airflow control.
• An alternate air source for easier access in the event of needing to share air with another diver. It is usually brightly colored in order to make is more easily distinguishable when needed.
• A connecting hose to the low pressure inflator on your BCD.
• A Submersible Pressure Gauge to monitor air usage (SPG or contents gauge) Essential for regularly monitoring your air consumption during the dive.

Regulators evolved from more than one separate source. The results follow:
• Constant flow regulators are common in many rebreathers. The second stage to the constant flow is an on off switch. Early designs were a bit heavy and interfered with dive duration and the most practical placement of the valve operating the on/off option. Before the fifties examples of these can be seen with le Prieur's breathers as well as Ohgushi’s teeth-operated version.
• The Twin hose demand valve variation is the earliest consisting of sometimes up to three stages, commonly fastened to the cylinder with an A-clamp. The root of its 'twin-hose' nature lies with one for air supply and the other for exhalation which monitors depth pressure. Cousteau's twin hose provided 140 litres per minute later raised to a standard of 300litres for the Porpoise by inventor Ted Aldred. Though loved by underwater photographers fore the visibility contributions as the bubbles exit behind the head, the twin hose has been obsolete since the 80's when the single hose regulator took over.
• Twin hose homemade regulators originated due to the unaffordable market value of the aqualung where sport divers used their initiative and threw together spare parts such as spring loaded diaphragms. The cylinders were nicknamed tadpoles due to their shape.
• Two stage single hose regulators are used most widely today. Its standard make-up is the first stage issuing hoses, subdivided into to different apparatus such as the first and second stage valve with direct feed, demand valve and octo (or alternate air source, in the event that you or your buddy nay need it) and the surface valve.