Why Use a Heated Hygrometer?

When the dew point temperature of a sampled gas is at a higher temperature than that of the sensing system, a condition of saturation or 100% Relative Humidity will occur within the sensing system. This causes liquid water to form within the tubing and internal portions of the sensing system and ultimately causes a system failure. Under these conditions, reliable dew point reading are not possible. The solution to this problem is to heat all of the components of the sensing system to a temperature above the dew point temperature of the sampled gas.

The Edgetech Instruments DPS series heated hygrometers have been specifically designed to solve this problem. The entire sampling system within each model including the chilled mirror sensor are heated. A heated sampling hose is provided to make connection to the process measuring point. The heated sensor allows the measurement of high dew points that are above ambient temperature. Without the heated system, condensation would occur and measurements could not be taken.

The DPS series uses the chilled mirror (CM) dew point temperature condensation principle to determine the water vapor concentration in gas mixtures, and a precision platinum resistance thermometer to measure the mirror temperature. The CM uses a thermo-electric device to control the temperature of the mirror in determining dew point. Since it is a direct measurement of dew point and thus a Primary Standard Measurement Technique, the DPS is highly regarded by pharmaceutical companies for monitoring fluidized beds, gas analysis laboratories, fuel cell testing facilities, air separation equipment, furnace operations and manufacturing facilities for its accuracy, quick dry down, fast response in detecting upset conditions and long life characteristics.


  • Wood Veneer Drying
  • Combustion Processes
  • Leakage testing: Nuclear Reactors
  • Fluidized Beds
  • Product Drying Chambers
  • Bakeries
  • Exothermic Process Chamber
  • Fuel Cell Testing
  • Furnace Applications
  • Pharmaceutical Powder Drying
  • Elevated Temp Process Chambers
  • Plastics/ Molding Process
  • Chemical Reactors Heat Treat/ Annealing Ovens

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