What Is a Portable Dew Point Meter?
A portable dew point meter is a device used for dew point measurements and spot checks. It is characterized by its small size.
The weight of the product is approximately 200g to 400g for the sensor part, and less than 1kg to 3kg for the main unit combined.
Because of its ease of installation and maintenance, it is often used for spot checks to verify quality.
Depending on the product and the type of power source, the continuous operating time is 10 to 48 hours, which is long enough to withstand dew point measurements in the field.
Bench-mounted dew point meters are also produced in portable sizes, although they require a power supply.
Uses for Portable Dew Point Meters
Portable dew point meters are widely used for dew point measurements and spot checks.
They can be used in a wide range of environments, from general air, to low dew point process environments, to pressurized air.
They are often used for quality checks, especially in industrial processes:
- Spot check of compressed air piping
- Dryer performance checks
- Spot control of dryer air
- Measurement of various gases, such as nitrogen, argon, etc.
- Spot control in industrial furnaces
- Moisture measurement of gas shutoffs
- Checking dryness of inert containers
- Checking of high purity gas lines
- Other monitoring and control of dryness in calibration rooms, laboratories, clean rooms, production plants, etc.
Principle of Portable Dew Point Meters
Since portable dew point meters are often used for fast spot check measurements in the field, many of them are easy to operate from sample connection to measurement.
Therefore, the sample connection can vary from an integrated type, a tube connection type, or a sensor type, all of which are characterized by their ease of use. In the case of the sensor type, the sensor part will be exposed, so it should be resistant to condensation.
There are two types of dew point measurement: the mirror-cooled type and the capacitance type.
In the mirror-cooled type, dew or frost forms on a small mirror inside the instrument when the sample gas is cooled and condenses.
This causes a change in the reflection and scattering of light on the mirror surface, and the dew point is measured by measuring the temperature at that time.
The capacitance method utilizes a capacitor with a layer of dielectric that reacts to the amount of moisture in the surrounding gas.
Ideally, the dielectric layer would absorb moisture at the same ratio as the surrounding moisture content, and this is used to detect the moisture content and determine the dew point.
Note that most portable dew point meters are capable of connecting to a PC and transferring data in order to handle measurement results efficiently.
Some can be connected to humidity probes or CO2 probes or can simultaneously measure temperature and humidity, and some have the ability to compensate for dew point fluctuations that depend on sample temperature changes by simultaneously measuring temperature.