Visual Dewpoint sensor

Citation

(2004), "Visual Dewpoint sensor", Sensor Review, Vol. 24 No. 2. https://doi.org/10.1108/sr.2004.08724baf.003

Visual Dewpoint sensor

Visual Dewpoint sensor

Keywords: Humidity, Machine vision

Building on the success of the Optidew Transmitter, Michell Instruments has developed Optidew Vision, a precision dewpointmeter with an LCD display panel (Plate 4).

The new Optidew Vision has been designed for the user who needs high accuracy, repeatability and stability of a cooled mirror instrument coupled with the value for money. Its bench-top format with carry handle and optional panel-mounting kit, combined with the convenient sensor probe design with cable length up to 30 m means that Optidew Vision can be used for a wide variety of applications. Calibration of RH sensors or environmental test chambers and precise humidity measurements in process environments such as engine emissions testing, are among the most important applications.

Plate 4 Optidew vision from Michell Instruments

Sensing the humidity of air or gases is achieved using the fundamental cooled mirror principle, in which a gold plated copper mirror is cooled electrically until it reaches the temperature at which condensation starts to form (the dew point). During this period, an electro-optical system detects the dew formation as a reduction in the light reflected from the mirror surface. A precision platinum resistance thermometer is used to measure this temperature and the resultant humidity level is displayed on the instrument front panel in any of a number of engineering units.

Optidew Vision provides a range of analogue and digital outputs and alarms, all configurable by connection to a PC running Michell's interface software, or via a link to a Palm OS based PDA. Both these interface programs allow datalogging and charting of the measured humidity.

Optidew Vision is the latest dewpointmeter in a long line of products that have firmly placed Michell at the forefront in the provision of precise, stable and reliable dewpoint meters for metrology and industry. As long ago as 1984, Michell sold its first such hygrometer to the National Physical Laboratory as part of their new National Humidity Standard. Since then, laboratory scientists and process engineers worldwide have benefited from Michell's expertise in the manufacture of these precision test instruments, and the company is recognised as a world leader in the field, supplying most of the major international standards organisations with dewpoint hygrometer systems.

For further information, please contact: Michell Instruments Limited at Nuffield Close, Cambridge, CB4 1SS. Tel: 01223 434800; Fax: 01223 434895; E-mail: info@michell.co.uk; Web site: www.michell-instruments.com