Advertisements
- Principle of operation is same as the Hygrometer.
- To operate, the frame is held horizontal and one drop of water is dropped on to the muslin cloth.
- The frame is whirled in open air for at least two minutes.
- Rate of evaporation at the Wet Bulb depends upon the speed of air flowing past the bulb.
- It reaches maximum at 7 knots wind speed.
- So readings unchanging and most reliable at speeds of 7 knots and above.
- In normal hygrometer, the speed of wind may vary, but in Whirling Psychrometer, speeds in excess of 7 knots are guaranteed when whirled at 1 revolution per second.
- Immediate reading is taken of the dry and the wet bulb.
- Essential that readings are taken immediately or else the wet bulb will give wrong readings.
- Obtain RH and the Dew Point from the meteorological tables meant for whirling Psychrometer.
- Very simple, and very accurate.