Semi-closed rebreathing apparatus with water removing pump

Abstract

A respiration system including a carbon dioxide absorber, wherein any water located in the exhaled gases, or present in the system due to leakage, is removed from the system before the exhaled gases reach the carbon dioxide absorber. The respiration system includes a supply of pressurized breathable gas connected to a first expansion chamber. A mouthpiece is provided for passing breathable gas to, and receiving exhaled gas from the user. The mouthpiece has an inlet and an outlet wherein the outlet is connected to the first expansion chamber. Means is provided for mixing the exhaled gas within the first expansion chamber with breathable gas from the breathable-gas supply. Water is removed from the exhaled gas in the first expansion chamber. An inhalation tube connects the first expansion chamber and the inlet of the mouthpiece. The inhalation tube provides communication of the gas mixture of the first expansion chamber and the mouthpiece. Means is provided for absorbing at least a portion of the carbon dioxide from the exhaled gases. The absorbing means is located along the inhalation tube between the first expansion chamber and the mouthpiece. A portion of the breathable gas from the breathable-gas supply is introduced to the inhalation tube between the absorbing means and the mouthpiece to compensate for any gas-flow resistance created by the absorbing means during high demand inhalation by the user.