Principle of measuring micro- SF6在线监测系统_SF6检漏仪_SF6传感器_SF6密度继电器

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Principle of measuring micro-water dew point by mirror condensation dew point method

发布时间：2016-03-11 来源：winfoss 浏览次数：40次

winfoss Detection Technology (Shanghai) Co., Ltd. specializes in the production of WINFOSS-P7 cold mirror dew point meter using mirror condensation dew point method to measure the dew point, to detect the gas dew point value as the humidity measurement standard or to judge the impact of gas moisture content on the production process.

Dew-point meter adopts high-precision measurement circuit and control algorithm to improve the self-diagnosis function of the software. Compared with traditional dew-point meter, it is small in size and light in weight, and requires humidification device, which improves the test time and reduces the gas consumption, so that the stability, service life and measurement accuracy of the product are greatly improved.

Its components are mainly composed of optical path part, refrigeration control part, gas path part and electronic display part, reasonable distribution, light volume, strong and durable.

1) Optical path part: mainly composed of light emitting tube, receiving tube and other devices optical path detection system, real-time detection of mirror condensation state.

2) Refrigeration control part: composed of mirror, cold reactor, base, heat pipe radiator and fan, the mirror is embedded in the cold side of the cold reactor, the cold reactor is embedded in the base, heat dissipation through the radiator and cooling by the fan. Strong cooling capacity, high efficiency.

3) Gas path part: The gas path part includes gas taking joint, sampling pipe, stainless steel needle control valve, quick plug, measuring chamber, flow meter, exhaust pipe, etc. The sampling pipe adopts polytetrafluoroethylene pipe with inner diameter of 4mm and wall thickness of 1mm to ensure measurement accuracy.

4) Electronic display part: using TFT3.5 color LCD touch screen, real-time display of the current measurement of dew point temperature, balance process curve, flow, time and other information. With alarm, self-detection, history storage and query, power and flow detection, calibration and other functions.

Measurement principle

Under constant pressure, the gas passes through the closed gas chamber at a certain flow rate. When the measured gas passes through the dew-point measuring chamber, the cold mirror passes by. When the mirror temperature is higher than the dew-point temperature of the gas, the mirror is in a dry state. After comparison and amplification of the control loop, the thermoelectric pump (composed of four-stage Peltier components) is driven to cool the mirror. When the mirror temperature drops to the dew point temperature of the sample gas, dew begins to form on the mirror, and the light is diffused on the mirror, and the reflected light signal induced by the photoelectric sensor is weakened. After comparison and amplification of the control loop, the thermoelectric pump is stimulated. The cooling power is reduced, so that the dew on the cold mirror is balanced with the water vapor in the gas through automatic control.

The mirror temperature is induced by a platinum resistor (PT100) temperature sensor close to the cold mirror, which accurately measures the temperature of the mirror (that is, the temperature of the dew layer), so as to obtain the dew point temperature of the gas. As a humidity measurement standard or to determine whether the gas moisture content has an impact on the production process to ensure production safety.