A dew point meter is used in compressed air systems to ensure the air quality which is used in the production and throughout all the processes in a factory. Not only protecting equipment and keeping the air quality at a certain level, but also for air quality audits according to ISO 8573-1 and ISO 8573-3 a dew point meter is absolutely necessary.

SUTO engineers have been developing dew point meters since more than 20 years, only with this experience it is possible to offer users precise and reliable measurement solutions for compressed air.


There are many benefits of installing a dew point meter to monitor the compressed air system

Have you ever had a failing dryer in your compressed air system, ruining your production output, but it was noticed until it was already to late? Dry compressed air is one of the most important quality parameters when it comes to process safety. When ambient air is compressed, the humidity in the air volume will rise drastically, therefore the air is easy to condensate by forming water droplets. What can be worse than having water droplets in the compressed air piping which can cause machinery breakdown, contaminating your process or even cause blockages.

Using an instrument to measure dew point, a so-called dew point analyzer or dew point meter, will help users to operate a safe and reliable compressed air system, notifying in case of alarms at early points and not when things are already got worse.

In the following section, we like to give an overview of the most important information regarding dew point measurement.

What is the dew point temperature?

The dew point describes the temperature when the water vapor in the air starts to condensate. Typically, the dew point temperature in ambient pressure and temperature conditions is around 12 to 14 °C Td. Everyone has encountered these phenomena in the daily life, take a cold beverage out of the fridge on a warm summer day, within seconds water droplets will start to build up on the beverage surface. The reason is, that the cold drink has brought the surrounding air to condensate its water vapor on the beverage surface, the dew point temperature was reached.

It is most common to name the above described temperature the dew point, pressure dew point or dew point temperature. But when temperatures are below 0 °C Td, the correct naming would be frost point instead of dew point. In the past 20 years the term dew point and dew point meter has been used and accepted, where frost point sensor or frost point meter would be the strictly correct term, but commonly not used in the industries.

Which measuring ranges can a dew point meter cover?

SUTO dew point transmitters are relying on two sensor principles in their dew point sensors. Polymer sensors for dew point between -60 … +50 °C Td and QCM sensor for a range of -100 … -20 °C Td. Combing both principles into a single unit, SUTO sensors are able to measure accurately the full range of -100 … +20 °C Td. SUTO offers a wide range of dew point meters, dew point monitors and OEM solutions to cover the range which is requested by our customers.

Even in high pressure applications up to 350 bar, SUTO dew point meters can be used. Our Service and Sales team is available to find the most suited dew point meter for your application and needs.

In which applications are dew point meters and sensors typically used for monitoring?

Dew point sensors are used in applications where it is crucial to monitor and guarantee dry process air. Dew point meters are used to gather the filed measurement data, react on the measured humidity values and in case of reaching limit values, triggering alarms or actuators.

In a modern paint shop system, the paint pistols are typically operated by compressed air. If water condensate would mix with the paint, it would easily lead to water contamination on the paint surface. This can destroy the paint shop output of a whole day production.

In the food industries, compressed air is often used to blow up packing containers, at any circumstances liquid water should never get into the process, firstly water is easy to carry bacteria and secondly who likes to open a bag of crunchy potato chips which are all squashy.

Dew point sensor are part of any process where a single drop of water could ruin the complete production output or harm machinery and other installed air consumers.

SUTO dew point meters are sustainable for following gases

The major focus of SUTO dew point sensors is the use of compressed air. But the sensor can be used in other pressurized gases, like CO2, Oxygen or Nitrogen. SUTO dew point meters always measure the dew point under the pressure, so-called pressure dew point. Still SUTO is offering many of the dew point meters with integrated pressure measurement, this enables users to output other humidity units as well, which are pressure depending, like atmospheric dew point.

If you want to use the dew point meter to measure the humidity, temperature and dew point in other gases, please feel free to contact our service team, we are sure we will find the best suited solution to fit your needs.

What makes SUTO dew point meters different from others?

SUTO can rely on a 20+ years experience in developing dew point sensors used in compressed air systems and pressurized gases. During that period of time, the engineers have continued to develop new measurement methods and even developed the own sensor elements for our innovative dew point meters.

The latest innovation is the dual-sensor module which combines two different measurement principles into a single measurement unit, using a QCM sensor for low humidity measurement and a Polymer sensor for standard humidity values. A Polymer sensor is typically used in dew point transmitters to measure the humidity of the air under pressure.

Polymer sensors are offering reliable measurement results paired with a fast response time and long term stability. These types of meters are typically used for fridge driers where dew points of +3 °C Td are expected.

How the QCM principle makes our Dew Point Meters better?

When it comes to high-tech applications, where often dew point of -60 … -100 °C Td are present, Polymer sensors are unlikely to show correct readings. Still, many manufactures are offering Polymer sensor for the complete range of -100 … +20 °C Td, which are not suited for an accurate measurement. To solve this, SUTO has developed their own sensor element, which is based on the QCM principle. This element is specially designed to measure in low humidity applications, providing users the most accurate measurement results.

The QCM sensor is based on an oscillating crystal, where on its surface water molecules can be trapped and cause a frequency shift. The QCM principle is the most advanced measurement principle to measure low humidity values and dew points down to -100 °C Td.

Dew point meter calibration, inspection and service

Like any other measurement tool, a dew point meter used in monitoring should be calibrated on a regular basis. When a new dew point meter is shipped out, it’s calibrated by the SUTO service team. This ensures that the measurement data is reliable, and the values are within the tolerance. In field, contamination like dust or other impurities can lead to inaccuracy of the measuring meters, therefore is recommended to calibrate the meters in regular time intervals.

Our service team will not only calibrate the sensor, but also carry out inspections, checking the sensor surface and therefore ensuring that temperature, humidity and the dew point are measured correct and accurate.

Accessories to be used with dew point meters

SUTO offers a wide range of useful accessories, completing the full range of dew point metering and monitoring. Typically, measuring chambers are most often used in compressed air system. When a dew point meter or sensor is used, it’s most important, that the air or gas flow passes the sensor element’s surface. This is crucial for an accurate measuring and fast response time. For installations where it is not possible to install the sensor tip directly in the air flow,

SUTO offers various measuring chambers as accessories. Chambers with quick connectors for fast and easy installation under pressure or by-pass chambers for measurements without any losses, as well as high pressure measuring chambers and many more. Ask our service team for expertise.

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