Second pressure-reducing stage for underwater use equipped with a bypass duct and method for making same

A second pressure-reducing stage for underwater use, comprising:

• a supply duct (107) of a breathable gas in which a valve of a pressure reducing device to reduce the pressure of the breathable gas is provided, the valve being interposed between an inlet of said supply duct (107) and a suction/exhalation mouth (102) to suction/exhale said breathable gas;
• a casing (106) containing pressure-sensitive means to control an opening/closing of said valve, the supply duct (107) and the suction/exhalation mouth (102) leading into said casing and being in communication therewith;
• and
• a bypass duct (101) for supplying at least part of a flow of said breathable gas from the supply duct (107) downstream of said valve, directly into the suction/exhalation mouth (102),
• wherein the by-pass duct (101) joins the suction/exhalation mouth through an opening having an axis oriented in a direction which converges towards a longitudinal axis of said suction/exhalation mouth.