Abstract: A method of making a cast hopcalite filter. The filter is formed by adding to "green" hopcalite a given weight of ceramic fibers. Additional water may also be added as required. This mixture is blended briefly in a high speed blender and then poured into a mold. Water is drained by vacuum through a filter paper in the bottom of the mold, preferably with the aid of a vacuum. The wet preform is then placed in a high temperature (600.degree. F. to 650.degree. F. ) oven for approximately 90 minutes for calcining. In this process the basic catalyst material saturates the fiber matrix before drying and transformation into its final chemical state.

Abstract: A high flow sodium chlorate oxygen generator assembly (10) of a relatively small diameter. The generator assembly includes a chlorate candle (12) mounted within a containment vessel (14, 16, 18), the chlorate candle being provided with a deep conical recess (54) which is thinly coated with a rapidly combustible material (56). Ignition of the rapidly combustible material is achieved by extending a hollow ceramic tube (58) from a primer (38) located at one end of the containment vessel, the hollow tube directing the flame from the primer, when ignited, towards the center of the deepest part of the conical depression. The above construction provides a high surface area for burning, and also intensifies the heat flux within the chlorate candle thereby substantially increasing the rate of oxygen output over known chlorate candles of comparable diameters.

Abstract: A closed circuit breathing apparatus such as that worn by personnel in irrespirable atmospheres. The apparatus is mounted on a backframe and housing 14 and is adapted to be interconnected with a face mask 12. The apparatus includes exhalation and inhalation passageways 18, 20, a source of breathing gas 50 which is released into the breathing apparatus at a constant volumetric flow rate, a carbon dioxide scrubber 38 and an ejector pump 40 which is driven by the source of pressurized breathing gas and which causes the pressurized breathing gas and exhaled air to be driven through the carbon dioxide scrubber at a relatively constant flow rate. The apparatus further includes a spring biased inhalation gas accumulator or counterlung 46 on the downstream side of the carbon dioxide scrubber, which counterlung is in communication with the inhalation passageway.