Method for introducing a gas and gas introducing device

A method for introducing a gas into a liquid, the method comprising:

• filling a gas volume enclosed below a free surface of the liquid and defined in a downward direction by an enclosed level of the liquid with the gas in sequential pulses wherein the gas simultaneously displaces the enclosed level of the liquid top down in a gas lifting channel until the enclosed level of the liquid drops below an inlet cross section of a gas flow out channel;
• subsequently
• flowing the gas out of the gas volume downward through the gas lifting channel, a deflection portion connected at a bottom of the gas lifting channel and closed at a bottom side, from the deflection portion in an upward direction through the inlet cross section and through the gas flow out channel connected to the inlet cross section at a top of the inlet cross section to the free surface of the liquid, wherein a blocking flow of the liquid flows downward through a compensation inlet that is arranged below a gas lifting channel inlet and above the inlet cross section into a compensation channel that is separated from the gas lifting channel by a compensation channel wall that extends between the compensation inlet and the inlet cross section so that the liquid flows into the inlet cross section and is moved along by the gas until the liquid fills the downward closed deflection portion and thereby closes the inlet cross section;
• initially only flowing the gas through the gas flow out channel after the enclosed level of the liquid has dropped below the inlet cross section until the enclosed level of the liquid rises above the compensation inlet;
• and only thereafter
• running the blocking flow downward through the compensation inlet to the inlet cross section.