Breathing air humidifier for respiration devices

DETAILED DESCRIPTION In accordance with the present invention there is provided a breathing air humidifier in which the compressible volume remains constant independently of the water consumption and which can be designed so small that in order to avoid condensation it can be mounted directly into the inspiration air supply close to the patient.
In accordance with the invention the evaporation surface is formed by a surface of a foil which is impervious to water but which is pervious to water vapor.
Warm water is brought into contact with one side of the foil while the gas to be humidified that is the inspiration passage is conducted past the other side of the foil.
With such an arrangement the physical process in the laryngeal, nasal and pharyngeal cavities is reproduced.
Through a large surface area, the evaporated water enters the inspiration air stream which flows past.
At the same time the stream is warmed up to the water temperature.
The amount of heat necessary for the evaporation and for the warming up of the breathing air can usually be taken from the water.
It is advantageous that the water quantity necessary for humidifying the inspiration air is removed from the water without changing the compressible vacuum volume.
According to a development of the invention the foil is made either by macroporous material which is made of a hydrophobic or it may be made of a microporous hydrophilic material.
Either of such foil materials may be used to separate the water from the inspiration air stream to be enriched with the water vapor.
The warm water contacts one side of the foil but it does not pass through the foil.
Only evaporated water in the form of water vapor passes therethrough into the stream of inspiration air flowing past the other side of the foil and it thereby increases its humidity.
The vacuum volume remains unchanged.
At the water contacted side of the foil the evaporated water is continuously replaced by a further supply of warm water.
According to a further development of the invention the evaporation surface is located in a receptable in which the foil is contacted on one side by water and on the other side by the gas to be humidified and the space of the water contacted side constitutes the flow return area of a thermostatically heated warm water circuit in which the water circulates from and into a supply tank