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Regulators. Objectives. Describe the regulator most commonly used for recreational scuba. Compare a single hose regulator to a double hose regulator. Compare an open circuit system to a closed or Semi-Closed system. Contrast upstream valves with downstream valves.
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Objectives • Describe the regulator most commonly used for recreational scuba. • Compare a single hose regulator to a double hose regulator. • Compare an open circuit system to a closed or Semi-Closed system. • Contrast upstream valves with downstream valves. • Describe the operation of a pilot valve regulator. • Identify and describe the function of the: • First Stage • Primary Second Stage • Octopus/Extra Second Stage (ESS) • LPI hose • Console • Explain why it might seem harder to breath while laying on your back. • Give 4 reasons why the regulator might breathe “wet”. • Explain why a regulator might free flow. • List considerations for a pre-dive check of your regulator including the significance of a discolored 1st stage filter. • Describe proper care and maintenance of your regulator.
Most Common Regulator • Single Hose • Open Circuit • Demand
Single Hose • First Stage mounts on the cylinder valve • Second connected by a single hose • Air exhausts from the second stage
Double Hose • Both stages in a single housing mounted on the cylinder valve • Mouthpiece is just a mouthpiece • Air exhausts from the housing behind the diver
Open vs. closed Circuit • Open circuit • Gas exhausts into the water • Rebreathers • Semi closed Circuit • Small volume of gas periodically escapes • Closed Circuit • No gas escapes • Typically used by technical divers • Require more • Training • Equipment • Preparation
Valve Design • Upstream valve • Forced closed by air pressure • Failure can shut off the flow of air. • Downstream valve • Air pressure acts to open the valve • Failure typically results in free flow • Pilot valve • Uses air pressure to both open and close the valve.
First Stage • Reduces Cylinder Pressure to a working pressure of approximately 125-140 psi.
Piston First Stage • Simple design • Few moving parts • Piston is exposed to the environment • Sealing kits are available
Diaphragm First Stage • More complicated design • More moving parts • Critical components are sealed from the environment.
Balanced vs. Unbalanced • Unbalanced First stage • Intermediate pressure will drop with cylinder pressure • Breathing resistance increases • Balanced First stage • Intermediate Pressure remains stable throughout change in cylinder pressure • Breathing resistance remains the same • Can be either Piston or Diaphragm
Types of First Stages Yoke vs DIN
Yoke System • Typically used for lower pressure systems • May be easier to use • More common in USA • DIN System • Typically used in High pressure systems • O ring is contained/more secure • May not be as convenient in the USA
Second Stage • The second stage delivers air at ambient pressure and volume. • Primary second stage • Used by the diver during the dive • Custom Mouthpieces
2nd Stage Features • Balanced vs. Unbalanced • Balanced allows use of a lighter spring • Easier breathing resistance • Adjustable • Adjust breathing resistance • Air flow/Volume • Adjust air flow/volume based on need
Trouble Shooting • Regulator breathes hard when supine • Pressure difference between 1st and 2nd stage • Regulator Leaks water • Torn mouthpiece • Torn Diaphragm • Inverted position • Exhaust valve problem
Trouble Shooting cont. • Regulator Freeflows • Second stage lowered purge down • Sand in purge • Sand behind lever “ears” • Low pressure seat problem • Immediate • Intermediate Pressure problem • Intermittent
Octopus/Extra Second Stage • Octopus/Extra Second Stage • Used in the event another diver runs out of air • offers slightly more breathing resistance than the primary. • reduces the likelihood of a free flow while diving.
LPI Hose • Used to add air directly from the cylinder to the BC
HP Console • Typically contains • SPG • Compass • Depth Gauge • May be an SPG only
Care and Maintenance • Keep the interior of the first stage dry • Have the dust cap in place when the regulator is off the cylinder valve • Fresh water rinse after diving • Ideally rinse with flowing water while on the cylinder • Soak with the dust cap in place. • Make sure to rinse the quick release mechanism on the LPI • Annual service
Purchase/Performance Considerations • Can the regulator meet demand at depth or high levels of exertion? • Can the regulator deliver high flow rates at low cylinder pressure? • Breathing adjustment • Flow/volume control • Exhaust resistance • Budget • Durability
Pre Dive check • Mouthpiece • Check for tears or holes • Hoses • Check for cracks, holes, soft spots, bubbles • Slide the stress relievers away from the 1st stage • Filter • Check for discoloration • Green = salt water in regulator • Rust = rust in tank • Oil = oil from the compressor • Black dust = carbon from the compressor filter • Inhalation check • Should not be able to inhale easily with your thumb over the filter opening in the 1st stage.