| 摘要 |
In a humidity or dewpoint-measuring instrument of the chilled mirror type, a light source (16), such as an LED and a photodetector (18) are mounted at locations remote from the cooled mirror (10) and fibre-optics (28, 30, 32) carry light from the light source (16) to the mirror (10) and, after reflection by the mirror (10), to the photodetector (18). This arrangement allows the mirror (10), with the fibre-optics (28, 30, 32), to be mounted within an elongate probe (114) of small diameter, and the light source and photodetector to be located, for example, in a box to which the probe is connected. Thus, the apparatus may be used to assess the humidity of hot gases, for example, without the light source (16) or photodetector (18) being affected by the temperature of such gases. |
