- Analytical sensors
- Dew point sensor LDH3
Dew point sensor - Dew point measurement in compressed air and inert gas applications
Monitoring the pressure dew point, a key parameter in compressed air and process gas systems, helps ensure both air quality and operational safety. The pressure dew point indicates the temperature at which the water vapour contained in the gas condenses.
Condensate leads to corrosion, can cause leaks, shortens the service life of systems and can have a negative impact on product quality. Dry process air is essential for trouble-free processes and compliance with standards, particularly in sensitive areas such as the food and pharmaceutical industries or in precision pneumatic control systems.
The pressure dew point is the temperature at which the water vapour contained in the gas begins to condense. Since gases under elevated pressure can hold less water vapour than under normal conditions, they reach saturation more quickly. If the process temperature then drops below the pressure dew point, condensate forms. This behaviour can be compared to a sponge: Only when it is compressed does it release water.
Dew point sensors are used to determine precisely this threshold – the temperature at which condensate forms at a given pressure. As a general rule: The lower the pressure dew point, the less water vapour is present in the process medium, and the more stable and reliable the process is.
Measuring the pressure dew point is therefore critical, as condensed water in the process can have serious consequences:
- Corrosion & rust reduces the service life and increases the maintenance costs of equipment and compressed air systems
- Increased energy consumption due to undetected leaks or incorrectly adjusted components
- Production disruption and downtime due to blocked pneumatic components, e.g. if rust particles break loose
- Quality defects in the product, such as bubbles in coatings or PET bottle production
- Moisture-related bacterial contamination of sensitive products
- Non-compliance with standards, e.g. ISO 8573-1
The calculator shows how relative humidity changes depending on temperature and pressure dew point. For simplicity, calculations are based on a pressure of 7 bar, while actual operating conditions may vary.
With increasing pressure, gases can hold less moisture at a given temperature.
As a result, the pressure dew point increases.
Transparent processes
Via IO-Link, both the pressure dew point temperature and the medium temperature are transmitted cyclically as process values.
If the pressure dew point falls below 0 °Ctd, the sensor outputs the frost point. At the frost point, water does not condense from the process air but forms ice in the line.
Loss-free data transmission with unshielded connection technology
IO-Link enables loss-free data transmission, as conversion losses are excluded via digital communication and external influences, such as magnetic fields, have no effect on data transmission.
Flexible remote configuration or directly on the HMI
The sensor can be configured quickly and easily via IO-Link, even remotely or during operation.
Planning to replace the device? The backup & restore function automatically backs up and restores parameter sets – only the device needs to be replaced.