Wet and Dry Bulb Hygrometers
Wet and dry bulb hygrometers consist of two thermometers, one of these has a dry bulb and the bulb of the second is kept wet. Hygrometers using evaporative cooling as a measure of humidity.
IMPA Reference: 370256, 370259, 370258
Features:
- Consisting of dry and wet alcohol filled glass thermometers fixed on a panel
- By differential indication between these thermometers, humidity can be read to the table mounted on a panel.
- Evaporation at the wet bulb lowers the temperature so this thermometer usually displays a lower temperature
- The Dry-bulb temperature represents the measured air temperature
‘Stevenson’ Screen
The Stevenson screen also known as an instrument shelter is a meteorological screen to shield instruments against precipitation and direct heat radiation from outside sources, while still allowing air to circulate freely around them. It forms part of a standard weather station.
IMPA reference: 370251
Features:
- Ideal to protect the thermometers/ hygrometers against radiation/precipitation
- To ensure optimum measurement of air temperature, relative humidity.
- Material: Kiln dried wood
Whirling Hygrometers
Whirling hygrometers, also known as sling psychrometers, employ the “wet” and “dry” bulb principle to determine % Relative Humidity.
They are designed to be rotated, by hand, to provide adequate and consistent ventilation of the bulbs.
IMPA reference: 370261
Features:
- Consists of two thermometers mounted on a frame that can be whirled in the air by hand
- The dry-bulb indicates the temperature of the air
- The wet-bulb thermometer is covered by a wet pick and helps determine the relative humidity.
- A handle enables the instruments to be whirled
- The % RH can be read off the side rule calculator integrated into the psychrometer.
Dial Thermo-Hygrometers
The dial thermo-hygrometer is a great choice for cabin use. The dial thermo- hygrometer is used to determine the relative humidity and temperature of environments, products, persons and materials.
IMPA reference: 370256, 370259, 370258
Features:
- Ideal for cabin use
- Wall mounted bi-metal thermometer with hygrometer
- Material: Chrome brass, steel
- Dial size: 130mm
