Valves
There is a huge variety of faucet types, from the tap with an outlet and backup device (virtually in disuse) to the two-outlet tap.
TAPS WITH RESERVE
In backup taps, this device basically consists of a valve closed by a spring calibrated to 40 or 50 bar of pressure. While the air inside the bottle has a higher pressure than the spring, it easily opens the valve and exits.
When the air pressure inside the bottle drops to a value equal to that of the spring, the forces balance, the air pressure is no longer enough to open the valve and the diver needs to make effort to overcome the strength of the spring and inspire.
By further lowering the pressure inside the bottle, the spring ends up keeping the valve closed, interrupting the passage of air. At this point the diver has to pull the “stopper from the reserve”, to manually cancel the force of the spring and open the valve, allowing the air to pass. The diver then breathes normally again, knowing that he is consuming the “reserve air”.
With the reservation system it is necessary to take two precautions:
- The bottle must be loaded with the reserve open (stick down).
- At the beginning of the dive the reserve should be closed (rod up).
Although used for a long time, one should never fully trust this system. If there is a spring deficiency (amazed spring), the diver has a lower air reserve than he should have; if by forgetting the reserve is not closed before starting the dive, or if during the dive the dip of the reserve dip is accidentally pulled (trapped in a rock, e.g. ), the diver is without any air reserve.
The YOKE AND DIN SYSTEM
Currently the reserve device has been replaced by the pressure gauge , ( Module T3 – Miscellaneous Diving Equipment), which allows to know at any time of the dive what air pressure is in the bottle.
Two-outlet taps can be type “Y” or type “T”.
The coupling of the regulator to the tap outlet can be done by the Yoke system (stirrup) or the DIN system (thread).
YOKE SYSTEM
In the Yoke system, the toric joint is housed in a seaboard around the tap outlet hole and it is on it that tightens the regulator stirrup.
DIN SYSTEM
In the DIN system (acronym for Deutsche Industrie Norm), the tap has a female thread where the regulator is screwed, which has a male thread, at the top of which is housed the toric joint.
THE DIVER MUST ALWAYS HAVE SPARE TORIC JOINTS IN order TO REPLACE A DAMAGED JOINT OR THAT HAS BEEN LOST
CARE
The handling of the taps should be done smoothly and without forcing. If you notice any difficulty when turning the handle, it is advisable to have the shaft checked, as it may be the gable shaft or just lack of lubrication.
The outlet of the taps must be protected with a plastic cover or wrapped with paper adhesive tape after filling, so as not to allow foreign substances to enter.
ALWAYS CLOSE THE TAPS GENTLY, WITHOUT TIGHTENING, SO AS NOT TO DAMAGE the HIGH PRESSURE JOINTS