Patent attributes
A heater unit for a respiratory system is designed for natural convection cooling air to pass first through a transformer in the heater unit and then through a heat sink in the heater unit to which is mounted a power switch to conduct heat from the power switch to the cooling air passing through the heat sink. A thermal break may be provided between the heat sink and the transformer. The transformer may be a toroidal transformer with the air passing through an aperture thereof such as from a hollow projection of the heater unit extending into the aperture. One side of the transformer may be situated along a surface of the heater unit and the heat sink secured to the heater unit against the opposite side of the transformer to hold the transformer in place. A venting chamber may be associated with an air exhaust of the heater unit to provide a circuitous exit path for air exiting the heater unit. The venting chamber may extend in generally surrounding relationship with the heater of the heater unit.