Dust Alarm 40

Filter Damage Monitoring with separate display

The DUST ALARM 40 is reliable, cost-effective instrument for the continuous monitoring of broken bags in Fabric Filter Baghouses. The instrument combines the benefits of ElectroDynamic™ Probe Electrification technology and separate control unit with a scaled 4-20mA output, dual local alarms and dual alarm relays, and a clear, simple icon-driven menu and display to deliver pragmatic and dependable broken bag monitoring.

The sensor can be used in metallic channels where dust particles are to be detected in the gas stream at dust concentrations of 1 mg/m3 up to 500 mg/m3.
The DUST ALARM 40 can also be used in hazardous areas (dust zone 2/ gas zone 2).

The DUST ALARM 40 is suitable for:

  • Stacks after bag filters, cartridge filters, cyclones
  • Flue gas velocities > 4 m/s
  • Non-condensing / dry flue gases
  • Not suitable for electrostatic precipitators or applications with water droplets


  • Immediate detection of filter damages
  • Detects all dust types
  • Usable in clean gas and dust channels
  • Very simple and fast retrofitting
  • Control Unit with full-colour, icon-driven menu and display 
  • 2 independent alarm set points
  • High accuracy signal providing reliable results
  • Expandable to 4 ... 20 mA output (trend signal)
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  • Technical Specifications
  • Applications
  • Operating Principle
  • Other Models


  • Stack diameter:            Up to 4 m
  • Flue gas velocity:    > 4 m/s
  • Dust level response:    < 1 to 500 mg/m³ (application dependent)
  • Ambient temperature:    -20 °C to +50 °C
  • Protection rating:    IP 65
  • Weight:                    900 g
  • Power supply voltage:    24 V DC (from the control unit)
  • Rod length:            100, 300, 600 or 1000 mm
  • Rod material:            Stainless steel
  • Sensor connection:    ½" BSP

Control Unit

  • Display:    Full-colour, anti-glare 2.8" LCD (4:3 ratio)
  • Weight:    1.2 kg
  • Outputs (standard):    2 x alarm relays (0.5 A DC @ 24 V)
    •        Optional:    1 x 4 ... 20 mA output (250 Ω, isolated)
  • Ambient temperature:    -20 °C to +50 °C
  • Enclosure protection rating:    IP 66
  • Power supply voltage:    80 - 230 V AC (50/60 Hz)
  • Cable entries:    3 x M16 cable gland
    •                   1 x M20 cable gland (for mains power cable)

The DUST ALARM 40 is used in a broad range of industries, where indicative filter failure monitoring is required after baghouses and cartridge filters, including the following types of processes:

  • Timber sawing plant
  • Chemical industry eg coating plant
  • Metals refining
  • Tobacco plant
  • Food industry e.g. packing/filling plant
  • Minerals industry e.g. brick, cement kiln

DUST ALARM 40 operates on the principle of electrodynamic measurement. 

As soon as particles pass or strike the probe, a charge transfer takes place.
From this, a measuring signal is generated which triggers a switching contact at a given limit value or is available as a current output.

The DUST ALARM 40 consists of a sensor and a control unit. The simple, icon-driven menu provides users with a language-free setup and system overview. With a 2.8” color display the correct function of the filter or an exceeding of the limit value are displayed visually during operation.
In addition, the DUST ALARM 40 as a standard comes with two independent relay outputs and an optional 4…20 mA output.