Structure of Household Ventilators Househol d ventilators generally have five components: host, humidifier, mask, pipeline and power supply. Among them, the main engine is mainly composed of motor, sensor, motherboard, control button and display LCD screen. The functional principles of human respiration: Inhalation: Contraction of respiratory muscles -- expansion of thoracic volume -- expansion of alveoli (forming negative pressure) -- inhalation of air from the outside world. Exhalation: Relaxation of the respiratory muscles -- elastic contraction of the alveoli -- increase of pressure in lungs -- and exhalation of air. It follows that the pressure difference between the expansion, contraction of the human alveoli and the atmospheric pressure forms the respiratory function. Therefore, the working principle of household ventilators is generally to control the turbine speed so that the airway pressure can reach the preset pressure and form pressure difference, so as t...