The Humilab utilizes the time-proportioned divided-flow technique developed by GE General Eastern to achieve relative humidity stability of 0.2 % RH. A built-in chilled mirror hygrometer continuously measures the test environment and provides feedback to the Humilab’s microprocessor controller.
The chilled mirror is a primary humidity instrument that controls a polished rhodium mirror surface to a thermal and mass equilibrium between dew formation and evaporation. A precision level of control is achieved by using infrared optics to control thermoelectric cooling and heating. The temperature of the mirror is measured with a precise platinum RTD and the resulting temperature is by definition the dew point. A second platinum RTID measures dry bulb temperature. Relative Humidity is computed from these fundamental measurements.
The Humilab provides accuracy of ±1.5 % from 10 to 80 % RH and ±2 % from 80 to 90 % RH. The test chamber measures 10.6 l in volume enabling several humidity instruments to be calibrated simultaneously with out sacrificing portability. The test chamber is constructed of stainless steel and is equipped with an onboard desiccant dryer and saturator. The Humilab is equipped with fittings to connect a water bath/circulator for standardized temperature control and for dry compressed air.
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