Michell”s new moisture and humidity calculator offers extended range of calculations

Phil Black - PII Editor 05/07/2010

273 1 minute read

Listen to this article

Humidity calculation slide chart

Michell Instruments have produced a new humidity calculation slide chart. Updated to include new measurement parameters, the slide chart allows for easy calculations and conversions between units of moisture content in parts per million (ppm), dew point, relative humidity and moisture in liquid.

Michell were prompted to re-design the slide chart in response to feedback from customers. ‘We discovered that our customers really valued the slide chart as a tool, but told us that they wanted it to do more calculations – such as moisture in liquids,’ explained Andy Benton, Technical Consultant at Michell. ‘We also found out that people find the slide chart useful because of its simplicity – you can use it anywhere, unlike on-line calculation tools.’

The slide chart offers a comprehensive selection of humidity units. High and low humidity ranges are covered on separate sides of the calculator for simplicity of use and also to enable the greatest range of conditions to be covered. One side is for making calculations with extremely dry gases containing only parts per billion (ppb) moisture content, of most relevance to sectors such as semiconductor industry. The other side is suited to calculations involving very high concentrations of water vapour – such as is found in paper production and certain metallurgical processes.

Parameters included on the slide chart:

•    Relative humidity
•    Absolute humidity, g/m3
•    Mixing ratio, g/Kg
•    Moisture content, ppmV, in gases
•    Moisture content, ppmW, in liquids
•    Dew point, °C, and vapour pressure

Pressure and temperature compensation is incorporated, where relevant, for each unit conversion. To complete the comprehensive coverage of the slide rule, metric/imperial conversions are provided for temperature and pressure.

The slide chart is a valuable tool for anyone working with processes involving moisture control or analysis. Michell are giving away versions of the slide chart for free to customers contacting them with enquiries regarding their current moisture applications and requirements. Simply visit www.michell.com/uk and complete the on-line enquiry form.