Patent ID: 7428902

Claim:
A humidifier system for heating and humidifying respiratory gases, comprising: a housing having opposite first and second ends and a chamber between said ends defining a flow path for respiratory gases, a first port at the first end for connection to a ventilator breathing circuit and a second port at the second end for connection to a patient to supply respiratory gases to the patient and to receive exhaled gases from the patient; a body of heat moisture exchange (HME) material within the chamber, the HME material comprising a material which can retain moisture and heat; a water permeable device of a water permeable material different from said HME material, the water permeable device located within the chamber and extending along at least part of the length of the body of HME material, the housing having a water refill inlet communicating with the water permeable device; a water supply outside the housing connected to the water refill inlet to supply water to the water permeable device; and a heater mounted outside the housing for heating the housing and maintaining the housing at a predetermined temperature; wherein the water permeable device is elongate and is wound around the moisture and heat retaining material in a spiral manner along at least part of the length of the HME material body, whereby respiratory gasses contact the water permeable device.