The difference between a cold mirror dew point meter and a precision dew point meter mainly lies in the following aspects:
Measurement principle:
Cold mirror dew point meter: a direct measurement method based on thermodynamic equilibrium. By precision refrigeration, the mirror surface is cooled down. When the water vapor in the gas sample flowing through the mirror surface changes to liquid state, this phase change point is captured by a high-sensitivity photoelectric system, and the mirror surface temperature is synchronously collected and output as the dew point value.
Precision Dew Point Meter: Thin film sensing technology, such as DRYCAP thin film sensing technology, is commonly used. It utilizes moisture sensitive materials, and when gas passes through, moisture is adsorbed on the surface of the material, causing changes in the dielectric constant of the sensing element. The dew point of the gas is reflected by measuring changes in relevant physical quantities.
Measurement accuracy:
Cold mirror dew point meter: It has high accuracy, usually within ± 0.5 ℃, and can reach ± 0.1 ℃ at high levels. It is one of the benchmark methods for dew point measurement.
Precision dew point meter: The accuracy is slightly lower than that of the cold mirror type, with a typical accuracy of ± 1.0 ℃ to ± 3.0 ℃.
Measuring range:
Cold mirror dew point meter: with a wide measurement range, typically covering -60 ℃ to+20 ℃, and some products can reach -80 ℃ to+20 ℃.
Precision dew point meter: It can generally meet the measurement range requirements of most industrial scenarios, but in terms of ultra-low temperature dew point measurement, it is not as widely covered as the cold mirror dew point meter.
Applicable scenarios:
Cold mirror dew point meter: suitable for fields that require strict measurement accuracy, such as analysis of dissolved gases in transformer oil in power systems, military industry, metrological verification, laboratory benchmark measurement, etc.
Precision dew point meter: mainly used for micro water measurement of non polluting gases such as H ₂ and SF ₆, commonly used for dew point measurement of SF ₆ gases in power systems, hydrogen in power plants, as well as industrial environments such as compressed dry air and power gas quality control.
Maintenance requirements:
Cold mirror dew point meter: It is necessary to regularly clean the mirror surface to avoid pollutants interfering with the condensation process, and the requirements for operators are relatively high.
Precision dew point meter: Although it also requires regular maintenance, compared to cold mirror dew point meters, its maintenance difficulty and frequency are lower.
Cost price:
Cold mirror dew point meter: The initial investment cost is relatively high, usually starting from tens of thousands of yuan.
Precision dew point meter: relatively low cost, more affordable price.