Duct Air Quality (VOC) Transmitter, QDT 24

The QDT 24 is ideal for:

• Air quality measurement in offices, hotels, meeting rooms, convention centers, apartments, stores, and restaurants.
• Quantitative evaluation of room air pollution caused by:
  • Cigarette smoke
  • Body perspiration
  • Exhaled breath
  • Solvent vapors
  • Emissions from building materials and cleaning agents
• Adjustable sensitivity to accommodate varying levels of air contamination.
• Energy-efficient room ventilation that activates only when air is polluted, reducing energy consumption.

• Self-calibrating sensor ensures consistent performance.
• High stability with marginal drift due to linearization and elevated operating temperatures.
• Non-selective gas assessment measures mixed gases rather than individual concentrations, making ppm measurements unavailable.
• Service life exceeds 60 months under normal conditions.

• Mixed gases and vapors (e.g., alcanoles, cigarette smoke, automobile exhaust).
• Combustion smoke (wood, paper, plastics).
• Compounds such as:
  • Alkanes, alkenes, aromatics, terpenes, halogenated hydrocarbons, esters, aldehydes, ketones.
  • Native VOCs like terpenes and isoprene.
• VOC emissions from construction products, furniture, cleaning agents, office chemicals, and carpets.

Sensor

• Type: VOC sensor (metal oxide) with automatic self-calibration.
• Protection: Sinter filter (exchangeable, easy to clean).

Measurement

• Range: 0–100% air quality relative to calibration gas.
  • Selectable sensitivity ranges: LOW, MEDIUM (default), HIGH via DIP switches.
• Accuracy: ±20% EW of final value (calibration gas reference).
• Response Time: < 10 seconds.
• Warm-Up Period: 1 hour.
• Minimum Flow Rate:2–0.5 m/s.

Power Supply

• 24 Vac/dc.

Outputs

• Selectable: 0-10 Vdc or 4-20 mA.
• Potential-free changeover contact (24V), adjustable switch point from 0–100% of the output signal.

Environmental Conditions

• Operating Temperature Range: -10 to +60°C.

Housing

• Material: Plastic (polyamide, 30% glass-globe-reinforced).
• Dimensions: 72 x 64 x 37.4 mm.
• Cable Gland: M 16 x 1.5, with strain relief (max inner diameter 10.4 mm).
• Protection Type: IP 65 (EN 60529, enclosure only).
• Protection Class: III (EN 60730).

Probe Tube

• Material: Polyamide (PA6).
• Dimensions: Diameter 20 mm, length 202.5 mm.
• Feature: Torsion protection.

Process Connection

• Mounting plastic flange included.

QDT 24

• Duct air quality (VOC) transmitter