BUCK RESEARCH MAKES HIGH PERFORMANCE HYGROMETERS FOR:

BRI Humidity Measuring Instruments

CR - 1A Cryogenic Hygrometer: Fast, Accurate Measurements to  -105 °C. Suitable for laboratory use, calibrations and spot checks

CR - 2 Cryogenic Hygrometer: Our flagship product. For use in aircraft and military applications.

CR - 3 Cryogenic Hygrometer: CR-2 Convenience for Continuous-Use Applications. Suitable for toxic and corrosive gases, such as Arsine, Phosphine, HCl and HBr.

CR - 4 Hygrometer:  Portable, 3-stage TE cooler for measurements to -65 °C

UHQ - 4P Hygrometer: Portable high-temperature hygrometer for measurements to 150 °C.

CR - 5 Hygrometer:  Separate sensor and transmitter with 3-stage TE cooler for measurements to -60 °C

1011C Aircraft Hygrometer: The Best Conventional Aircraft Hygrometer

BRI also distributes the VAPORTRON^® humidity calibration chamber and the VAPORPAK^® portable humidity calibration chamber.

Why Chilled Mirror Hygrometers are Inherently Reliable

How they work

The heart of a chilled mirror hygrometer is the sample chamber, through which the gas to be measured flows. The chamber contains a coolable mirror and an optical system that measures the mirror reflectivity. During operation, the mirror is cooled until dew or frost begins to condense on it, changing the reflectivity and the optical output. The optical signal drives electronics that control the temperature of the mirror to maintain a constant layer of condensation. The mirror is therefore held at the dew/frost temperature. The dew/frost temperature is a fundamental property of water vapor and therefore an inherently reliable measure of moisture concentration. A temperature sensor imbedded in the mirror provides a direct measure of dew/frost temperature.

Why they are inherently reliable

Chilled mirror hygrometers are inherently reliable because of this operating principle, and because the dew/frost temperature is measured directly - there is no need to convert parameters such as resistance, voltage, etc., to humidity  through a calibration equation. We ensure temperature reading accuracy by using ultra-stable mirror temperature sensors that are calibrated against a  NIST-traceable reference standard.

During operation, no long-term error can exist. If an error in mirror temperature somehow appeared, its dew or frost layer would immediately  begin to increase or decrease, and the control circuit would heat or cool the mirror to restore the proper frost layer. Therefore, as long as the control system is operating, the mirror temperature must remain exactly at the dew/frost point.  

BRI specializes in producing high performance chilled mirror hygrometers that  are exceptionally fast, accurate, and operate over a very wide humidity range.