Nevco Engineers Pvt. Ltd.
Opacity Dust Monitor

Opacity Dust Monitor

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Provided Opacity Dust Monitor is optical equipment outlined to estimate the concentration of particulate matter or dust in exhaust gas traveling through a flue, stack or duct. This version of dust monitor deploys dual pass light transmission assessment method, with folded beam reflector or transceiver arrangement. A light ray is discharged from transceiver that goes through the flue, duct or stack to reflector that afterward bounces back the light to transceiver in which receiver light’s intensity is estimated. In our opacity dust monitor, enhanced particulate intensity in stack gas reduces transmitted light as well as induces the received light’s intensity to fall. When combined against defined reference measurements, the minimization in force can be employed to estimate particulate concentration and exhibit reading in mg/m3.

Key features:

  • Fitted with zero and automatic calibration check feature
  • Integrated software for data logging, control and result storage
  • Design allows simple installation and relocation
  • In situ assessment linearly in exhaust gas circulation
  • Assessment reading as minute as mg/mg3
  • Green led for immunity and prolong stability to ambient light
  • Rugged construction from 316 stainless steel
  • Interface alternatives for simple integration
  • Operator interface option with various mounting configurations
Technical specification



Measuring Principle

Light Transmission

Operating Wavelength

510 – 540 nm (green LED)

Measurement Reading

Concentration (mg/m3)

Measuring Range

0 – 1000 mg/m3 (user configurable)

Path Length (duct diameter)

0.5 – 10 m (flange-to-flange separation)


+ / - 2 %


0.1 mg/m3 (display resolution)


1 – 60 s (user selectable)

Drift with Temperature

+ / - 2 % (over 20 °C)



+24 Vdc (optional 90-260 Vac PSU available)

Nominal Current Consumption

400 mA

Power Up Current Consumption

400 mA

Purge Air Supply Volume

50 – 200 L/min (to each air purge body)

Purge Air Quality

Suitably filtered, oil free and dry


Serial Comms

ModBus RTU via RS485
Internal USB (OI)
External USB (TRX)

Analogue Outputs

4.0 – 20 mA (isolated and scalable)

Relay Contacts

3 A @ 30 Vdc (signal level and service alarms)


Ambient Operating Temperature

-20 – +55 °C (air temperature around the equipment)

Exhaust Gas Temperature

Up to +600 °C (heat insulating gaskets included)

Ambient Operating Humidity

0 – 100 %

Ingress Protection

IP65 for external use


316 Stainless Steel (powder coated)


153 x 120 x 122 mm (measuring head)


2.5 kg per head

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