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PDT Dewpoint Transmitter
A highly efficient and economical solution designed for trace moisture measurement in gases and dry compressed air, particularly suited for applications requiring monitoring of higher, ‘wetter’ dewpoints.
The PDT Dewpoint Transmitter offers a practical approach to continuous dewpoint measurement, catering for diverse requirements down to -60 °C dewpoint and available with three specific dewpoint ranges: -60 °C to +20 °C, -40 °C to +30 °C and -20 °C to +50 °C.
The compact 2-wire, 4-20 mA loop-powered transmitter features a bulk polymer sensing element — delivering excellent accuracy, stability and response speed across various dewpoint ranges. It is engineered to withstand pressures up to 5,000 kPa (50 barg), ensuring robust performance under demanding conditions. It offers IP65/NEMA 4 protection and for enhanced safety and reliability, the electrical connections are made via a durable M12 industrial connector.
Whatever the challenge — Alpha Moisture Systems has you covered.
- Highly customised solutions
- Trusted by industry leaders
- Distributors worldwide
- Over 30 years experience
Economical and reliable trace moisture monitoring
Key features
- Durable bulk polymer sensing element that ensures sensitivity, repeatability, and rapid response time, facilitating accurate moisture monitoring in critical applications
- Can be fitted directly into the pipeline or our dedicated Sensor Holder/Sample Cell for optimum sampling conditions and easy removal for annual calibration
- Compact design makes installation easy and requires minimal maintenance, reducing operational downtime
- IP65 / NEMA 4 weatherproof protection, ensuring the dewpoint transmitter is safeguarded against environmental conditions
- Supplied with a calibration certificate traceable to National and International Humidity standards, affirming the reliability and accuracy of the transmitter
- Compatible with DS1200 or DS4000 displays for expanded monitoring capabilities
- Compatible with DIS030, a compact 4-20 mA loop-powered local indicator that mounts directly on the transmitter for immediate readings
Technical Data
General | |
| Sensor/Transmitter Type | 2-wire, 4-20 mA loop powered transmitter |
| Approvals | CE, UKCA |
| Factory Calibration | Supplied with a calibration certificate traceable to National and International Humidity standards |
| Documentation | Instruction manual, calibration certificate |
Sensor | |
| Sensing Element | Polymer |
| Dewpoint Range | Overall range offered between -60 °C to +50 °C (-76 °F to +122 °F) -60°C to +30°C (-76°F to +86°F) -40 °C to +30 °C (-40 °F to +86 °F) -20 °C to +50 °C (-4 °F to +122 °F) |
| Accuracy | ± 2 °C (±3.6 °F) dewpoint |
| Sensor Calibration | Supplied with a calibration certificate traceable to National and International Humidity standards |
| Temperature Coefficient | Temperature compensated for operating range |
| Sample Flow Rate | Flow independent, ideally 2 - 3 L/min |
| Response Times | Wet to dry: less than 30 secs Dry to wet: less than 10 secs |
| Calibration Warranty | 12 months from date of dispatch |
| Operating Temperature | -20 °C to +70 °C (-4 °F to +158 °F) |
| Storage Temperature | -40 °C to +80 °C (-40 °F to +176 °F) |
Electrical | |
| Electromagnetic Compatibility (EMC) | Complies with BS EN ICE 61326-1 |
| Display | Compatible with 4-20 mA loop powered indicators |
| Power Supply | 24 Vdc (10 Vdc – 30 Vdc) |
| Warm Up Time | 10 seconds |
| Fault Conditions | Short circuit/over range: display reads “Short” and output drives to 24.0 mA |
| Output Signal | Linear 4 to 20 mA with selectable engineering units |
| Operating Voltage | 24 Vdc (10 V - 30 Vdc) |
| Maximum Series Resistance | ≤ 500 Ω |
| Isolation | Sensing element connected to the 4-20 mA loop but isolated from transmitter body |
Mechanical | |
| Dimensions in mm (H x W x D) | 123.2 x 32.3 (H x W) |
| Weight | 200 grams |
| Operating Pressure | 0 to 50 bar |
| Operating Humidity (External) | Maximum 95 %RH non-condensing |
| Operating Temperature | -20 °C to +70 °C (-4 °F to +158 °F) |
| Storage Temperature | -40 °C to +80 °C (-40 °F to +176 °F) |
| Cable | Supplied with 2m standard cable. Nominal diameter 3.4mm, 92 Ω/km at 20°C |
| Cable Terminations | M12, 5-pole |
| Sensor Protection | 316 sintered stainless-steel filter – 50 micron |
| Weatherproof Classification | IP 65 / NEMA 4 when the connector is coupled to the transmitter |
| Mechanical Warranty | 12 months in case of defective parts or faulty workmanship |
| Compatibility | Transmitter holder |
| Enclosure/Body | Stainless Steel |
| Probe Material (Wetted Parts) | 316 stainless steel |
| Mechanical Connection | G1/2” |
Downloads
What's in the box
PDT Dewpoint Transmitter
PDT Manual
PDT Cable
Calibration Certificate
Applications
AerospaceFor the production of high-specification aeronautical parts, vacuum furnace heat treatment with dry argon is essential, and NADCAP mandates the testing of welding shield gas at the torch head for dryness. Our range of transmitters provides continuous trace moisture measurement, ensuring the feed gas for shielding stays within the required moisture content range, maintaining ideal conditions.
Breathing AirHigh moisture levels in breathing air, as used in diving, firefighting, and defence applications, pose health risks and discomfort. Moisture condensation from high humidity levels in compressed air can lead to blocked airlines or cylinder corrosion, with potentially fatal consequences. Our transmitters allow for the continuous monitoring of trace moisture throughout the pipe network.
Food and BeverageMoisture control is critical in the food and beverage industry to prevent food quality loss. Packaging foods in an atmosphere of dry gases like Nitrogen and carbon dioxide extends shelf life. Our AMT and AMT-Ex transmitters enable continuous trace moisture measurement, reducing waste and carbon footprint.
HDPE ProductionEthylene and propylene, key for manufacturing chemicals and plastics, require precise moisture content monitoring for polymerisation efficiency and catalyst yield. Our range of transmitters ensures process optimisation, product quality, and reduced maintenance costs by providing accurate and consistent trace moisture measurements.
Injection MouldingMoisture adsorbed on plastic pellets can lead to extrusion failures and quality degradation. Our transmitters measure trace moisture in the circulating air to detect possible dryer failures, enhancing process efficiency and reducing costs.
Medical GasesIn medical applications, compressed air and gases must be clean and almost sterile, free from contaminants including water vapour and bacteria. Our AMT and AMT-Ex transmitters offer permanent moisture monitoring in air/gas lines, which is essential for maintaining safe patient care environments.
Natural Gas and LNGThe liquefaction and regasification processes in natural gas supply are crucial for global energy distribution. Moisture presence poses risks of pipeline and valve freezing. Installing the AMT-Ex dewpoint transmitter ensures accurate trace moisture measurement, safeguarding gas quality and system integrity.
PharmaceuticalsIn pharmaceutical manufacturing, accurate moisture determination is crucial for product consistency and quality. Our range of transmitters provides fast, repeatable, and accurate online dewpoint control, essential for the control of blanketing gases.
Power GenerationEnergy production priorities include safety, cleanliness, and efficiency. Our range of online transmitters measures trace moisture, protecting equipment, reducing costs, and improving efficiency in power generation processes.
Welding GasesDifferent welding processes require specific inert gases for atmospheric shielding. Our AMT and AMT-Ex transmitters continuously measure moisture to ensure feed gas used for shielding remains within the specified range, maintaining optimal conditions for welding.
Frequently Asked QuestionsIf you have a question that’s not answered below, please contact us
Which sensing technology is used in the PDT dewpoint transmitter?
The PDT dewpoint transmitter employs a bulk polymer sensing element, known for its exceptional sensitivity, rapid response, and high accuracy.
Is the PDT dewpoint transmitter suitable for hazardous applications?
What dewpoint ranges and units are available for the PDT dewpoint transmitter?
What dewpoint ranges and units are available for the PDT dewpoint transmitter?
Which display controller is recommended for use with the PDT?
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Whatever the challenge,
you can rely on Alpha
Moisture Systems
If you require a customised trace moisture measurement solution, book a consultation with our expert technical team and find out how you can increase the efficiency and productivity of your operations.
Dewpoint Calculator for Trace Moisture Measurement
in Gases & Compressed Air