To provide an intermittent flow of gas to a patient effective for curing without giving any feeling of wrongness to the patient, by installing a cushioning tank at an upstream and/or at a down stream of an automatic regulating valve to operate according to an aspiration cycle of the patient.
In a gas supply unit that oxygen-enriched gas is blowing through a nose cannula 7 after passing through a duct 5 equipped with a cushioning tank 4, an aspiration phase detection means 9 installed at a branch of the duct 5 converts pressure changes of aspiration into electrostatic capacitance. The signal is further converted into electric pulse signals which are converted finally to pulsed signals per unit time. When the fluctuating value calculated from the detection means 16 of an aspiration starting point using the obtained digital signal is larger than a specified value, then the point is recognized as an aspiration starting point. Then, the time difference T between this aspiration starting point and the starting point of the previous cycle is measured by an aspiration cycle measuring means 20. A specified time T1 stored in a memory means 22 is compared to T, and when T ≤T1, then a valve operating means 30 controls an opening of a valve 3.
OBATA DAISUKE
HANAOKA YASUKI
