Dew point is a specific temperature—technically referred to as "dew point temperature"—at which water vapor in the air begins to condense as the temperature drops.
When compressed air is cooled, its relative humidity rises. If the temperature falls to the point where relative humidity reaches 100%, water droplets begin to separate from the air; this specific temperature is known as the compressed air's "pressure dew point."
The "dew point temperature" measured at a pressure of one atmosphere is referred to as "atmospheric dew point" or "ambient pressure dew point."
Dew Point Meter Selection and Industry Applications
A dew point sensor—or dew point meter—is an instrument capable of directly measuring dew point temperature; it is a type of temperature and humidity sensor. When selecting a dew point meter, it is generally necessary to confirm the required measurement range with the user and determine whether integrated pressure measurement is needed. Integrating pressure measurement offers the advantage of outputting real-time gas pressure data alongside humidity units that require pressure-based conversion—such as simultaneously outputting atmospheric dew point, ppm, or g/kg values while measuring pressure dew point.
Compressed Air Industry
Air compressors compress air, resulting in a product that contains significant amounts of high-temperature water vapor. Consequently, drying equipment is required to remove moisture and prevent condensation.
Application: Measuring gas moisture content at the dryer outlet.
Pharmaceutical Industry
In the pharmaceutical industry, most drugs are highly sensitive to fluctuations in humidity and moisture content; therefore, monitoring temperature and humidity is essential to ensure the quality and performance of the final product.
Applications: Stability testing, production areas, production equipment, and quality assurance.
Semiconductor Industry
Semiconductor manufacturing requires optimized humidity environments, and electronic testing specifications often mandate specific temperature and humidity conditions.
Applications: Cleanroom monitoring, photoresist printing, printed circuit board (PCB) manufacturing, drying processes, production testing, and storage.
Petrochemical Industry
In many petrochemical processes, strict control of moisture content maximizes production efficiency and optimizes equipment performance.
Applications: Hydrogen recycle gas in catalytic reforming; dehydration of ethylene gas and solvents in polymer production units, etc.