Compressed Air Dew Point control: How to prevent damage

The modern production technology needs compressed air. The diversity of application starts with non processed blast air to absolute dry, oil free and sterile compressed air. Irrespective of how it is used, compressed air has to be dry. Depending on the application considerable economical damage can be caused by uncontrolled humidity irruption into the compressed air system.

Reasons that can lead to an increased pressure dewpoint value within the compressed air system

• Condensate at the refrigeration dryer (condensate eliminator faulty or dirty)
• Condensate overload of the refrigeration dryer
• Adsorption agent is not regenerated sufficiently
• Compressed air bypass in the bypass (valve faulty or not closed)
• Compressed air bypass in the refrigeration dryer (worn out, corroded etc.)

Water in compressed air leads to damages

• Corrosion within the pneumatic plant - Rust will develop in the ducts and functioning elements and will lead to leakages.
• Breakage of the lubricating film – Broken lubricating films lead to mechanical faults.
• Building of electric elements.
• Formation of ice in the compressed air system - At low temperatures the water within the compressed air system could freeze and cause frost damage, reduction of the diameter and blockades.
• Material handling - High humidity leads to conglutination of materials to be transported, e. g. sugar, concrete, granulate, etc.
• Pharmaceutical -High humidity impairs powders, tablets, etc.
• Hospital - DIN 13260, EN 737-3, danger of development of bacteria

The high quality standards in industry require the continuous monitoring of humidity with results which are reliable and invariable over a long period.

We provide stand-alone units or sensors with analogue output that can be integrated in to a centrally controlled system.

Sigma 200 & Sigma 201 series Dew point sensors with display and alarm

The Sigma 200 & Sigma 201 series Dew point sensors provide reliable and long term stable dew point monitoring in industrial applications. The newly developed sensor features improved signal and stability in demanding industrial applications. Drifts caused by temperature changes, dust and agιng are eliminated by the electronics providing reliable measurements. Recalibration interval could thus be increased to 2 years.

The measured dew point is output via a 4-20 mA signal output. The integrated display shows online measurement values and alarm status. One alarm can be programmed which will activate a relay.  Sigma 200 / 201 feature a complete dew point sensor, display keyboard and alarm.

Sensor parameters such as analogue output scaling, alarm values, units, etc. can be easily changed by using a service kit. This kit is used to connect the sensor to a PC for configuration changes.

Features
• Dew point sensor for low dew point applications down to -60 ºC
• Long term stability
• Graphic display
• Relay output
• IP65 casing provides robust protection in rough industrial environment
• Very fast response time ensures safe and reliable indication whenever dew points are out of valid ranges
• Can be installed directly into dryers through G 1/2” thread
• High accuracy of ±2 ºC dew point

Technical information

Sigma 212 Dew point sensor

Ideal and reliable sensor for membrane or adsorption dryers.

The Sigma 212 dew point sensors provide reliable and long term stable dew point monitoring in industrial applications. The newly developed sensor features improved signal and stability in demanding industrial applications. It makes it an ideal choice for dew point measurements in desiccant dryers.

Drifts caused by temperature changes, dust and aging are eliminated by the electronics providing reliable measurements. Recalibration interval could thus be increased to 2 years.

The measured dew point is output via a 4-20 mA signal output. The compact size of the sensors make them an ideal choice for installations in tight environments. Sensor parameters such as analogue output scaling, alarm values, units etc. can easily be changed using the service kit. This kit is used to connect the sensor to a PC for configuration changes.

Features
• Dew point sensor for low dew point applications down to -50 ºC
• Long term stability
• IP65 casing provides robust protection in rough industrial environment
• Very fast response time ensures safe and reliable indication whenever dew points are out of valid ranges
• Can be installed directly into dryers through G 1/2” thread
• High accuracy of ±2 ºC dew point

Technical information

Sigma 215 Dew point sensor

Ideal and reliable sensor for  refrigerant dryers.

-20 – +50°C, measuring chamber, with M12 connector (straight type)

The Sigma 215 Dew point sensor provides reliable and long term stable dew point monitoring in industrial applications. With these new models dew point measurement in refrigerant dryers becomes affordable and can replace traditional temperature measurement which often couldn’t tell the real dew point. Η215 outputs the measurement value through the loop powered 4-20 mA signal.

Features
• Affordable dew point sensors for mid-range applications such as refrigerant dryer monitoring
• Long term stability
• IP65 casing provides robust protection in rough industrial environment
• Very fast response time ensures safe and reliable indication whenever dew points are out of valid ranges
• Can be installed directly into dryers through G 1/2″ thread
• High accuracy of ±2 ºC dew point

Sigma 220 Dew point sensor

Dew point sensor, -100 … +20 ºC, G 1/2” thread, 16 bar, 1 x 4…20 mA.

The Sigma 220 Dew point sensor provides reliable and long term stable dew point monitoring in industrial applications. Sigma 220 is using a new sensor technology which has superior signals at very low moisture levels thus providing reliable measurements down to –100 ºC.

A stainless steel mesh filter with pore sizes below 1 um protects the sensor from particles. It’s designed for applications where very low moisture levels needs to be detected.

The measured dew point is output through a 4-20 mA signal (3-wire or loop powered). Sensor parameters such as analogue output scaling, physical units, can be easily changed by using a service kit.

Stated accuracy under following conditions:

• Ambient temperature 23 +/- 3 ºC
• Process temperature 23 +/- 3 ºC
• Ambient humidity <95%, no condensate
• Airflow > 1 l/min at sensor tip

Features

• Small size makes it ideal for dryer installations
• Measures dew points down to –100 ºC
• New sensor technology
• Version with integrated pressure measurement
• Various output versions available: 1 x 4…20 mA, 2 x 4…20 mA, RS-485 (Modbus), 4…20 mA loop powered
• Very fast response time ensures safe and reliable indication whenever dew points are out of valid ranges
• IP65 casing provides robust protection in rough industrial environment
• Can be installed directly into dryers through G 1/2” thread
• High accuracy of 2 ºC dew point
• M12 connector

Sigma 220 is powered by a current loop, and three wires.

Sigma305 Dew Point Monitor

2 models: -50 ... +20°C Td and -20 ... +50°C Td

Refrigerated-Dryers are among the most used dryers in compressed air. Many of these dryers are not performing as intended, too often a lack of maintenance and quality issues result in very high dew points and water in the pipes. In other words: Energy is used for nothing. The dew point indicator at the dryer is not really measuring the dew point but the evaporation temperature. Only the “real”dew point measurement of the outlet air provides reliable results.

The All-In-One solution allows a convenient and price attractive dew point monitoring of refrigerated dryers. Alarm indications offer a timely maintenance avoiding costly system shut downs.

Under normal operation conditions Η305 can be used for 2 years without any re-calibration.

Stated accuracy under following conditions:
• Ambient temperature 23 +/- 3 ºC
• Process temperature 23 +/- 3 ºC
• Ambient humidity <95%, no condensate
• Airflow > 1 l/min at sensor tip

Technical information

Α red light and buzzer alarm, wall mountable version is also available.

The unit is using the relay outputs of H305 to trigger the alarm