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.

Abstract: A mouthpiece unit of a diving respirator wherein a device for opening and closing an aperture of a mouthpiece side of a mouthpiece unit body is provided, and a part of a respirable gas for operating the device is applied to the device through a valve which is opened by the jaw of a diver and a pilot valve which is opened by an inspiration of the diver. A water exhaust port communicating with a gas room of a mouthpiece side formed in the mouthpiece unit body and a valve for closing the water exhaust port are provided on the mouthpiece unit body, the valve being opened when the gas room is increased in pressure.

Abstract: A throttle valve of a diving respirator, wherein an orifice valve is inserted slidably in a hole of a cylindrical valve body, an orifice is formed in said valve body so as to communicate a gas outlet and a gas inlet formed on the valve body, and a gas passage is formed between the gas outlet and the gas inlet, which is opened only when a gas pressure in the gas inlet is elevated to a predetermined valve so that the orifice valve is moved relative to the valve body.