The Polymeter is a combined hygrometer-thermometer for measuring and determining:
- air temperature,
- absolute and relative humidity,
- Saturation vapor pressure,
- steam pressure,
- Dew point and
- Saturation deficit.
It is characterized by easy handling and high operational reliability.
The measuring mechanism components are made of brass and have a matte chrome finish. All axes are mounted in stone, ensuring minimal static friction.
A glass thermometer filled with alcohol serves as the measuring element for the air temperature.
The humidity-dependent change in length of natural hair is used as a measuring element for determining relative humidity. The specially treated hair is characterized by low reading inertia, even at very low temperatures. Therefore, hair polymeters are also suitable for outdoor measurements. For measurements in production and storage areas, polymers with synthetic fibers are recommended, as they require less maintenance (regeneration) and are less susceptible to contamination.
| Measuring ranges:
|
0...100% RH |
-35...+45 °C |
| Measurement accuracy: |
± 3% RH |
± 1 K alcohol thermometer |
| Scale division: |
1% RH |
1 °C |
The polymeter is particularly important for nighttime frost forecasting, which is based on the following physical laws: At night, the ground radiates its heat into the room; this occurs most strongly when the sky is clear. The cooling of the ground is transferred to the air layers near the ground. However, there is a limit to the cooling of the air. When the dew point temperature is reached, the water vapor contained in the air condenses, releasing heat. If the dew point is 0 °C or below in the evening, there is a risk of frost overnight.
The main features of the Polymeter with hair hygrometer and alcohol thermometer are:
- Can be used down to 0 °C,
- When the relative humidity fluctuates, the natural hair regenerates itself,
- low hysteresis of the hygrometer,
- high reaction speed due to rolled hair,
- Alcohol thermometer with backed scale,
- good handling,
- high reliability and
- easy to use.
