摘要 |
A flow control device for supplying oxygen to a medical patient using provides pulses of oxygen only when the patient inhales, using a flow valve unit that receives a pressurized oxygen supply and delivers a controlled oxygen supply output through a cannula to a patient. A pressure sensor detects breathing changes and output signals that are amplified and automatically corrected for signal errors, such as those caused by offset voltage and temperature drift, by use of a negative integral feedback module that includes automatic correction circuits and a switch for selectively disconnecting the feedback. The amplified sensor signal generates control signals, including an output pulse delivered to the flow valve, having a pulse width that is a user adjustable for control of the opening and closing of a valve, such as a three-way solenoid valve, for outputting time selectable pulses of oxygen to the patient when patient inhalation is detected by the pressure sensor. |