Abstract: A gas flow control system for an anesthesia apparatus, which has an oxygen gas pressure reducing valve for reducing primary pressure of oxygen gas to secondary pressure, and a anesthetic gas pressure reducing valve for reducing primary pressure of anesthetic gas to secondary pressure. A pressure control valve is connected to the secondary side of the anesthetic gas pressure reducing valve and responsive to the secondary pressure of the oxygen gas for controlling the secondary pressure of the anesthetic gas. The pressure control valve is so arranged that when the secondary pressure of the oxygen gas is zero, the pressure control valve is closed to cut off the supply of the anesthetic gas.

Abstract: Improvements in a flow restrictor for use in a flowmeter measuring a flow rate according to the pressure drop caused by laminar flow, utilizing the fact that the pressure drop is proportional to the flow rate. The flow restrictor comprises a cylindrical member, and a housing having a fluid inlet and a fluid outlet for accommodating the cylindrical member, wherein at least one groove or spiral groove for passing fluid is formed in the peripheral direction of the cylindrical surface of the cylindrical member or in the peripheral direction of the inner surface of the housing forming a cylindrical cavity for accommodating the cylindrical member.

Abstract: An apparatus for supplying a mixture of oxygen and an anesthetic gas at a predetermined flow rate and mixture ratio. The flow rate and mixture ratio are controlled by means of electrically operated throttle valves, responsive to output signals from an electronic control system, generated in accordance with data stored in the control system and with input signals applied to the computer from means for sensing the flow rates of the oxygen and anesthetic gas. Desired flow rate and mixture ratio data may be input by using a numeric keyboard, and are digitally displayed.

Abstract: An anesthesia apparatus which comprises at least two flow meters, an oxygen gas supply means for supplying oxygen gas to one of said flow meters, a nitrous oxide gas supply means for supplying nitrous oxide gas to another one of said flow meters, at least two flow rate adjustment valves disposed between the one of said flow meters and said oxygen gas supply means and between said another one of said flow meters and said nitrous oxide gas supply means, respectively, each of said flow rate adjustment valve including a valve element having a predetermined shape to vary the rate of flow of each of said gases substantially in proportion to the amount of movement of said valve element, a flow control means connected to said flow rate adjustment valves for actuating said valves, and a flow rate adjustment means operatively connected to said flow control means and operative to set a selected angular position of said flow control means with respect to said flow rate adjustment valves for thereby determining the relati