Humidity control in apressure support system

A method of humidifying a flow of gas generated by a pressure support system for delivery to an airway of a subject, the pressure support system, the method comprising:

• holding liquid in a humidification chamber that forms a flow path between a gas inlet and a gas outlet, the gas inlet being configured to receive a flow gas into the humidification chamber and the gas outlet being configured to release the flow of gas from the humidification chamber;
• directing such a flow of gas through the humidification chamber along the flow path between the gas inlet and the gas outlet such that the humidification chamber is pressurized by the flow of gas;
• controllably heating the liquid within the humidification chamber separately from the liquid held in the holding chamber such that the flow of gas flowing through the humidification chamber from the gas inlet to the gas outlet is humidified by the heated liquid;
• and
• receiving liquid from the humidification chamber into a holding chamber positioned adjacent to the humidification chamber as the flow of gas elevates pressure within the humidification chamber, wherein the holding chamber is divided from the humidification chamber by a partition that defines an opening between the humidification chamber and the holding chamber through which the liquid is received, and wherein the opening and holding chamber are formed such that the reception of liquid from the humidification chamber into the holding chamber causes the level of liquid within the humidification chamber to be reduced to a level that is substantially lower than the level of liquid in the holding chamber.

A humidifier for use in a pressure support system, the humidifier comprising:

• a holding chamber;
• a humidification chamber positioned adjacent to the holding chamber, the humidification chamber defining a flow path between a gas inlet and a gas outlet, the gas inlet being configured to receive a flow of gas into the humidification chamber and the gas outlet configured to release the flow of gas from the humidification chamber;
• a heating element configured to controllably heat liquid within the humidification chamber separately from the liquid held in the holding chamber such that the flow of gas through the humidification chamber from the gas inlet to the gas outlet is humidified by the heated liquid;
• and
• a partition configured to divide the humidification chamber from the holding chamber, wherein the partition defines an opening between the humidification chamber and the holding chamber such that fluid is communicated between the humidification chamber and the holding chamber through the opening, and wherein the opening is formed such that the partition and liquid held in the humidification chamber isolate the flow path formed by humidification chamber from the holding chamber causing the flow of gas through the humidification chamber to result in pressurization of the humidification chamber that reduces the level of liquid within the humidification chamber to a level that is substantially lower than the level of liquid in the holding chamber.