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a device for avoiding damage to power plants in case of an explosion of fuel gases, coal dust, or other substances. Blast valves are openings (a window, scuttle, or similar device) in the parts of power plants in which there is a danger of explosion; they are closed by doors or a material such as asbestos canvas that is easily destroyed in case of an explosion. A blast valve with a pipe to draw off gases protects service personnel from burns. Furnace chambers, the gas conduits of steam boilers and furnaces, and apparatus for preparing pulverized coal are equipped with blast valves.