Apparatus for measuring very low water content in gas.

摘要

A method is disclosed for measuring the amount of water in a gas with a very low water content which comprises using a dew-point meter or a frost-point meter comprising: a reflecting mirror whose temperature is variable in the range of from room temperature to the temperature of liquid nitrogen; a gas ejecting nozzle disposed so as to face said reflecting mirror; means for projecting either a condensed light ray or a laser beam onto that portion at which dew and/or frost is formed; and means for detecting a sudden increase in the intensity of scattered light, the process comprising: a step of cooling a gas to be measured so that its temperature becomes close to that of the mirror; a step of ejecting the gas from the said nozzle so as to hit said reflecting mirror; a step of projecting either a condensed light ray or a laser beam onto that portion of the mirror surface against which the gas to be measured is blown; and a step of detecting a sudden increase in the intensity of scattered light, thereby measuring a low dew point in the range of from -80 DEG C to the temperature of liquid nitrogen.