Breathing apparatus for scuba diving with semi-closed circuit gas recycling

A semi-closed circuit gas recycling scuba diving breathing apparatus intended to be carried by a diver, comprising a breathing loop intended to be connected to at least one gas tank, the breathing loop comprising:

• at least one mouthpiece intended for the diver and making it possible for the diver to breathe in the breathing loop,
• at least one recycling chamber connected to an outlet of a nozzle and intended to recycle at least some of a gas exhaled by the diver so as to supply a recycled gas, said at least one chamber being configured to receive a device for filtering the exhaled gas, and
• at least one breathing bag having an outlet connected to an inlet of the mouthpiece, an inlet connected to an outlet of the at least one recycling chamber and at least one inlet intended to be connected to at least one outlet of the at least one gas tank, the at least one breathing bag being configured to make it possible for a mixing within it of the recycled gas coming from the at least one recycling chamber and at least one fresh gas input, coming from the at least one gas tank,
• the apparatus comprising a plurality of ducts making it possible for connections in parallel between at least one inlet of the at least one breathing bag and at least one gas tank, the apparatus comprising:
• a first duct of said plurality of ducts, equipped with a first, fixed, nozzle, configured to deliver at a constant volume flow, a first fresh gas input to the at least one breathing bag,
• an additional duct of said plurality of ducts, equipped with a demand regulator configured to deliver an additional fresh gas input to the at least one breathing bag,
• said apparatus being characterised in that it further comprises at a location of said plurality of:
• a second duct of said plurality of ducts, equipped with a gas flow regulator configured to deliver at a variable volume flow, a second fresh gas input to the at least one breathing bag,
• wherein said apparatus also comprises at least one diving condition sensor configured to measure at least one diving condition parameter taken from among a physiological parameter of the diver and a pressure of water surrounding said apparatus, and wherein,
• said apparatus is configured to control the gas flow regulator so as to make said variable volume flow vary, at least according to at least a data related to said at least one diving condition parameter.