Gas Quality Monitoring: Why are Dew Point and Oxygen Content Key Indica"&"tors?
The quality of protective gases directly affects the purity and quality of graphitized products. Among many gas quality indicators, **dew point** and **oxygen content** are two of the most critical monitoring parameters.
Dew Point: A Measurement of Water Vapor Content
Dew point refers to the temperature at which water vapor in a gas begins to condense into liquid water. The lower the dew point, the lower the water vapor content in the gas.For "&"high-purity graphite materials:
- The dew point of the protective gas must be below -60°C.
- The corresponding water content is approximately below 10 ppm.
Why such a low requirement? Because even trace amounts of "&"water vapor at high temperatures will react with carbon materials, producing carbon monoxide and hydrogen, leading to product oxidation and a decrease in purity. For every 10°C increase in the dew point, the oxygen content in the product may double.
Oxygen Content: Directly Measures Oxidation Risk
The oxygen content in the protective gas directly determines the degree of oxidation of the product:
- Semiconductor-grade graphite: Requi"&"res an oxygen content of <>1ppm
- Ordinary high-purity graphite: An oxygen content of <10ppm is acceptable
Excessive oxygen content directly oxidizes the surface of carbon materials at high temperatures, resultin"&"g in a whitening appearance and decreased performance of the product.
Online Monitoring Methods
Our system is configurable with:
- Online Dew Point Meter: Real-time display of pr"&"otective gas dew point, alarm for exceeding limits
- Oxygen Analyzer: Real-time monitoring of oxygen content, alarm for exceeding limits
The readings of both instruments are displayed in real-time on the operating "&"interface, making it easy for operators to understand. Automatic alarms are triggered when limits are exceeded; for severe exceedances, interlock protection (automatic shutdown or gas source switching) can be set.
Recommendation: For high-purity products, a dew point meter and oxygen analyzer are essential configurations. Monitoring dew point and oxygen content is like giving the protective gas a ""physical ex"&"amination""; only those that pass the examination can be used.