Abstract: A breathing system with a facepiece that includes a first port adapted to be placed in fluid connection with the outlet of a regulator assembly to introduce pressurized breathing gas into the facepiece; a second port adapted to be connected to an air purifying system; and an exhaust valve through which the user's exhausted breath can exit the facepiece. The breathing system also includes a pressure adjustment mechanism that includes a communication link in communicative connection with an actuator such that the exhaust pressure adjustment mechanism sets the internal facepiece pressure required to open the exhaust valve, independently of the respiration of the user, to a first pressure when the actuator is in the first state, to a second pressure when the actuator is in the second state. The first pressure is higher than the second pressure.

Abstract: An infrared fluid analyzer with an improved sensitivity and signal to noise ratio is provided. The device includes a capacitor microphone for detecting absorption of characteristic infrared wavelength lines by the sample and utilizes an electret material to electrically polarize the capacitive element in the microphone. The device is used to detect a stoppage of respiration in a person and thereby warn of the presence of an APNEA condition. The capacitor microphone generates a signal each time it detects an exhaled breath. When a timer senses an extended delay between signals, an alarm sounds indicating the presence of an APNEA condition.

Abstract: An air supplying hood has a top wall, to which the upper edge of a flexible plastic front wall is connected, with the upper portion of the front wall forming a transversely curved front window. A flexible back wall behind the window is connected with the top wall and the sides of the window to form with the window an open-bottom enclosure for a person's head. The lower portion of the flexible back wall and the front wall below the window form areas shaped to fit over a person's shoulder and lie against his chest and back. Above those areas is a hollow band extending around the hood and communicating with the lower ends of circumferentially spaced hollow vertical struts with which the wall of the head enclosure is provided. The band and struts are inflatable by an air tube extending through the back wall for supplying air to the head enclosure.