Flow controller

摘要

An oxygen flow controller for use in administering oxygen from a pressure-regulated source on demand to a patient through a nasal cannula is disclosed. A flow path is opened by a solenoid valve in response to the negative pressure created in the nasal canula by the patient's inhalation. The valve is opened for the interval needed to maintain an inhalation to exhalation ration of one-to-two, and the timing cycle and the open and closed duration times of the valve are made to automatically match the patient's breathing.