METHOD OF MEASURING THE DEW POINT AND/OR FROST POINT OF A GAZ HAVING LOW WATER CONTENT

摘要

A method of determining the dew point or frost point of a gas containing a very small amount of water using an optical dew point meter including a reflector mirror the temperature of which can be varied from room temperature to any point of -80 DEG C or below, a means of contacting said reflector mirror with the gas to be measured, a means of irradiating said reflector mirror with focused rays of light and/or laser light, and a means of detecting the change in scattered light and/or reflected light due to the dew and/or frost condensed on said reflector mirror, said method gradually reducing the temperature of said reflector mirror, either before or while said reflector mirror and said gas contact, thereby condensing dew and/or frost on said reflector mirror; and following the formation of dew and/or frost on said reflector mirror, adjusting the intensity of scattered light or reflected light from a maximum value to a constant level, at a controlled temperature and determining the temperature at that constant level of light intensity as the dew or frost point.