Breathing aid apparatus

An artificial respiration apparatus comprising a tip connectable to a source of gas under pressure, said tip including a bore hole; a valve seat at the end of said bore hole facing away from the source; an outlet connectable to the respiratory system of a patient; a movable valve member cooperating with said valve seat to close said bore hole, a spring cooperating with said movable valve member and biasing the same against said valve seat, a housing including a first chamber communicating with said source of gas and also with said outlet when the moving valve member is not in contact with the valve seat; and a second chamber in which said spring is housed, one wall of said second chamber being formed of said movable valve member, a channel communicating said first chamber with said second chamber, a pellet of porous material disposed in said channel which produces a loss of pressure therein; and a pressure screw cooperating with said pellet for varying the compression thereof, thereby adjusting the flow of gas from said first chamber to said second chamber.