| 摘要 |
A device for measuring gases and aerosols with a detector tube, comprises, a duct or test tube for the passage of a test gas therethrough which includes a forelayer in the duct through which the test gas is passed, and which has a substance which will react with the test gas to form a new gas substance. The gas-permeable forelayer advantageously acts as a filter for the aerosol and comprises a substrate, such as a silica gel or a glass fiber, which is impregnated with a material, such as zinc dust and arsenic trioxide which is saturated with water. The aerosol which contains a sulfuric acid in the gas will react after deposit in the forelayer with the zinc forming a nascent hydrogen which reduces the arsenic trioxide immediately to arsenic hydride. The test tube also contains an indicating layer with a material which is known for producing an indication of the newly formed gaseous substance.
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