difficulty breathing. These levers were easily bumped out of the up position during the dive and the diver would be using the last air without knowing it. You will see “J” valves in use, but the valve is always used with the reserve lever in the down position. The mechanism is rarely used because divers now use submersible pressure gauges to monitor their air supply. DIN Valves The DIN valve system originated in Europe. The DIN valve has a large, threaded opening and the regulator first stage screws into the valve (figure 2-13). This system is also known as the captured O-ring system. While common in the rest of the world, DIN valves are not commonly seen in the United States. The DIN valve is capable of operating at pressures higher than 200 bar (3000 psi). Burst Disks Every cylinder valve is equipped with an over-pressure relief disk or burst disk. This disk is designed to allow the cylinder to vent excessive pressure by bursting Chapter 2- Diving Equipment the disk. This relief mechanism is designed to rupture and prevent an explosion if the cylinder becomes seriously over-pressurized. Maintenance Proper care of your cylinder includes rinsing the outside with fresh water after using the cylinder, having the cylinder visually inspected each year or if the cylinder is emptied, and having the cylinder hydrostatically tested as required by government standards. Visual Inspection Scuba cylinders must be inspected internally and externally at least once per year at a professional dive shop or a dive-equipment repair facility by a certified cylinder inspector. The cylinder is inspected for dents, marring, and fire or heat discoloration on the outside and for corrosion, water, and cracks inside (figure 2-14). Diving Equipment 23 FIGURE 2-14. YOUR SCUBA CYLINDER MUST BE VISUALLY INSPECTED AT LEAST ONCE PER YEAR. FIGURE 2-13. DIN VALVES ORIGINATED IN EUROPE AND ARE CAPABLE OF OPERATING AT PRESSURES GREATER THAN 200 BAR (3000 PSI).
19116TC
To see the actual publication please follow the link above