Thermoelectric Cooling Solutions

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Dew Point Hygrometers

Dew point sensors (hygrometers) have a number of applications ranging from meteorology (humidity measurement), monitoring of the environment to the applications in industries, in the gas industry (humidity of hydrocarbons) and others.

Among the instruments for the measurement of relative humidity and dew point, particular in terms of accuracy and performance there are devices that are based on so-cold "cold mirror” - Cooled Mirror Dew- Point Hygrometers.

This optical sensor records temperature at which water condensation starts on the optical mirror. The temperature is changed by a thermoelectric Peltier cooler (TEC). Fixing the dew point is made by sharp change in reflectivity mirrors with water on its surface. The temperature is measured by a precise temperature sensor.

Dew-point is observed both in the cooling cycle (condensation) and heating mode (evaporation).

In such devices, advantages of thermoelectric coolers are used - to heat and cool by a simple change of the polarity of the power supply voltage, and to provide unique rapid rate of change of temperature on level 1-10°C per second.

Relative humidity can vary widely and in many applications need exact change in a wide range from almost zero humidity. Therefore, the thermoelectric cooler should provide rapid and deep cooling.

General requirements to the TEC in such applications are the following:

  • Two- or three-stage TEC types (for deep cooling).
  • Ability of high rate of heating/cooling cycles.
  • Durability to multiple cycles of heating-cooling.
  • Protection against moisture of testing environment.

RMT produces different types of multistage TECs suitable for use in dew point sensors.

The series MC and MD of standard modules contain two- or more stages suitable for such applications.

Performance optimization is possible by using thin ceramics with high thermal conductivity - Aluminum Nitride Ceramics.

For protection against moisture dispersed into the test environment, RMT provides a special way of protection-all interior surfaces of the TEC thin chemically resistant coating - parylene.

The company RMT, based upon the experiences of the dew sensor modules can be optimized or the development of special design of thermoelectric modules to meet customer requirements.

RMT also offers assembly of sensors on our own equipment.

All the products are manufactured in whole conformity with the standard of reliability Telcordia GR468 Core. The modules of RMT are fully compliant with RoHS и REACH requirements.

To select a suitable solution and the optimal TEC for an application, the supporting Online TEC Assistance is available at RMT’s website. For detailed modeling and calculations the company RMT provides our customers by free software TEC Cad or iTECPad.

And contact RMT for advice and assistance.