Point the red pointer of the adjusting device to the value to be adjusted.
The hood inside the mound is made according to the Venturi principle, that is, when oxygen enters the mask through a narrow hole, negative pressure is generated around the jet airflow, and a certain amount of air flows into the mask from the edge of the opening, and the size of the seam at the edge of the mask changes the ratio of air to oxygen. Because the airflow injected into the mask is greater than the maximum flow and tidal volume when the patient inhales, the concentration of oxygen inhalation is constant, and because the high-flow gas constantly washes the inside of the mask, the exhaled air is difficult to stay in the mask, so there is basically no repeated breathing. When treating patients with hypoxemia and hypercapnia, it is necessary to use Venturi mask to accurately control the oxygen concentration.
Venturi effect, also known as Venturi effect. This phenomenon is named after its discoverer, Italian physicist Giovanni Battista Venturi. This effect is manifested in the phenomenon that when the restricted flow passes through the reduced cross section, the velocity or flow rate of the fluid increases, and its flow rate is inversely proportional to the cross section. According to Bernoulli's law, the increase of flow velocity is accompanied by the decrease of fluid pressure, which is a common Venturi phenomenon.