DISC HUMIDIFIER - GARTHUR
Date of manufacture:
The mesh disc assembly is normally contained within the aluminium housing. The assembled device is placed into a breathing system close to the patient's mouth where is experiences the warm moist air that is exhaled through it. The exhaled gas mixture is saturated with water vapour. On impinging upon the cold steel mesh, water vapour condenses to coat the surface of the wires with liquid water. The heat of condensation warms the wires. During the next inhalation, cool inhaled gas mixture is warmed and takes up water vapour as it passes over the mesh, in turn cooling and drying the latter. By this means, water and heat are conserved. The number of mesh layers is designed to maximise the efficiency of the device without excessively adding to the respiratory dead space of the breathing system. Later versions of this device were housed in a plastics casting. Metal has been largely superseded as the active element in favour of fibrous plastics materials on current, single use devices. They are now identified as Heat and Moisture Exchangers (HME) and may be comined with a bacterial filter.