GB191016693A - A New Method of Preparing Oxygen for use in Respirators, Life Saving Apparatus, Recharging Oxygen Cylinders, and for other purposes. - Google Patents

Abstract

16,693. Harger, J. July 13. Oxygen.-In the manufacture of self-heating mixtures for preparing oxygen, such as mixtures containing a highly oxygenated salt, e.g. potassium or sodium chlorate or perchlorate, and, as a catalyst, manganese dioxide or ferric oxide or other like peroxide, the constituents are very finely subdivided and thoroughly mixed, and the mixtures are compressed under high pressure into suitable form, with one or more rods, wires, &c. passing therethrough to prevent breaking-up during use. If precipitated manganese dioxide, ferric oxides, &c. is used, little or no combustible substance is required in the mixture; when, however, combustibles &c. are used, lamp-black or a substance not generally regarded as a combustible, such as potassium ferrocyanide or ammonium bichromate, is employed. The precipitated oxides used as catalysts may be obtained as waste products of certain processes, for example if " Weldon mud " be treated with dilute acid to remove calcium carbonate, suitable precipitated manganese dioxide results. In an example, suitable proportions of chlorate, catalyst, and lamp-black are sieved through a "70 mesh" sieve, and the thoroughly mixed powder, preferably moistened, is compressed and moulded about one or more wires &c., each rod being provided with a match-head or other known igniter at one end to start the combustion. In a modification, the moulded bodies may be made with a core of the mixture described above, with or without an increased proportion of heating- agent, surrounded by a mixture of chlorate and catalyst, or vice versa. The compressed rods may be placed or fed end to end in use to provide a constant supply of oxygen. According to the Provisional Specification, the heat-producing agent may, in some cases, be kept separate from the oxygen-yielding mixture, as by using separate but contiguous vessels. A catalyst mentioned is ferric hydrate. Suitable combustible materials mentioned are powdered charcoal, wood flour, powdered coal, powdered metals, phosphorus, and hydrocarbons. In some mixtures, where carbon dioxide is formed, caustic potash or soda is admixed to combine with the dioxide. Other heat-producing agents are iron sulphide, finely divided iron, or lime, sodium, sodium peroxide, &c. used in conjunction with moistening.