An improved standard humidity generator based on bubbling sulfuric acid

摘要

In modern industrial production, controlling the water content in the environment is extremely important. With a large number of trace moisture detector was widely used, there is an urgent need for a reliable device for calibrating trace moisture analyzers. Conventional standard humidity generators used for calibration are too complicated and expensive to calibrate field devices. A portable device for preparing a trace amount of water based on the method of the saturation partial pressure of sulfuric acid is introduced in this paper. The principle of this device is that when the sulfuric acid at different temperatures and concentrations, the equilibrium water vapor pressure is different and remains constant to produce a constant concentration of trace gas, which can calibrate the trace moisture detector. In order to prevent the infiltration of external moisture, and to adapt to the corrosive environment of the chemical industry, gas piping and valves inside the device are made of metal pipe or Teflon material. The temperature control system inside the device can control the error within the range of about ± 0.1 degrees Celsius. After the experimental test, the error range of the instrument is ± 5 percent, when the calibrating gas is greater than 100 umol/mol. Which can meet the vast majority of moisture detector calibration and well adapt to the complex environment. The instrument has high reliability, simple structure and low cost, which is suitable for widely used and popularized. In addition, the instrument has expanded the function of the instrument combining Zigbee wireless communication technology and Internet of things technology. Meanwhile, detailed principle and structure of the improved standard humidity generator based on sulfuric acid bubbling method was introduced in this paper.