Durag D-R 250 Dust Monitor – Combined Probe

The DURAG D-RX 250 is certified dust monitor, combined with a flow, temperature and absolute pressure measurement for monitoring of small to medium dust concentrations in dry flue gas and process gas.

Key Benefits

  • Only one probe / mounting hole in the exhaust duct
  • Allows calibration to measure the dust concentration in mg/m3
  • Compact design, no moving parts, no consumables
  • Allows calibration to flow in m3/h
  • LCD displays measured values
  • 4 analog output signals
  • Parameters are set at the control device without a PC
  • Control and evaluation unit can be located in a distance up to 1000m


Suitable for dust mass concentration measurement

  • at incineration in general,
  • at installations according 2000/76/EC WID / 17 BImschV
  • at garbage, hazardous waste incinerators,
  • at facilities for cement production
  • at installations according 2001/80/EC LCPD / 13 BImschV / Clean Air Act
  • at power stations with gas, oil, coal or co-firing
  • at installations for the incineration of biomass
  • at facilities pursuant to 27th BImschV

Suitable for monitoring of filter systems
The measurement principle is not suitable for use directly behind electrostatic filters.

Download Specifications


Stack, Process & CEMS


measurements tribo-value – dust-concentration
differential pressure – velocity – flow rate
sample gas temperature
absolute pressure
sample gas air, fluegas, non flammable process gas
dust concentration**
(typical values at the site)
2 – 50 / 5 – 100 / 10 – 200 / 20 – 500 mg/m3
sample gas velocity*** 7-35 m/s
duct diameter > 0,3 m
sample gas temperature 0 – 200°C / 350°C*
sample gas pressure (relative to ambient pressure) -100 bis +300 hPa
sample gas moisture 20 … 80% rel. humidity
ambient temperature -20 to +50 °C
measuring principle dust: measuring the transfer of electrical charge from dust particles to an electrode in flowing sample gas
flow: measuring the differential pressure created by a multi point pitot tube
type in situ, mounted at stack, probe is in contact with sample gas
system components D-RX 250 S measuring head
D-RX 250 T transmitter
D-RX 250 D display and control unit
D-FL 100 DDMH differential pressure transmitter
D-RX 250 G purge air unit*
measuring ranges 0 – 100% Tribo value, at 8 ranges
0 – 400°C
0 – 10hPa / 60 hPa* differential pressure
800 – 1300 hPa absolute pressure
expanded uncertanty
EN14181 / EN ISO14956 / EN15267-3
better than 2,8 mg/m3
at particles 1-2micron
output ranges assignment of tribo value to an analog output, either as raw value or scaled as dust concentration in mg/m3 after correction of changing flow
assignment of dP signal to an analog output, either as raw value or scaled as flow speed in m/s or scales as flow rate in m3/h or mN3/h
assignment of T-Signals to an analog output
assignment of P-abs-Signal to an analog output
process connection flange, similar to DN65 PN6, pitch circle 130mm
tube, ID=70, L= 120mm
flange, similar to DN80 PN6, pitch circle 150mm
tube, ID=100, L= 200mm*


signal output 1 x RS 485 Modbus RTU
status output 1 x transistor output, in operation
supply 24 V DC from D-RX 250 T
protection IP65
dimensions (h x w x d) 180 x 180 x 360 mm + length of probe
380 x 205 x 465 mm + length of probe*
lenght of probe: 250 / 400* / 700* / 1000* mm
weight 9,5 kg
material Al cast alloy, painted RAL 5017
isolator: ceramics
probe: 1.4571
signal output RS 485 Modbus RTU
status output 1 relay output, max load 48 V / 0,5 A
status input 1 input for external dry contact – maintenance
signal input 2 x 4-20mA connected to Pabs- and, dP-Transmitter
supply 90-264 VAC, 48-62 Hz, 10 VA, supplies D-RX 250 P
ambient temperature -20 – 50°C
protection IP 65
dimensions (h x w x d) 270 x 190 x 135 mm
material housing: Al cast alloy, painted RAL 5017
weight 5 kg
measuring range 0 – 10 hPa
signal output 4 – 20 mA
supply 14 – 32 VDC, from D-RX 250 T
ambient temperature – 40 to 85 °C
protection IP 65
dimensions (h x w x d) 190 x 120 x 90 mm
measuring range 800 – 1300 hPa
signal output 4 – 20 mA
supply 14 – 32 VDC, from D-RX 250 T
purge air rate 5 – 10 m3/h
supply 90 – 264 V, 47 – 63 Hz
dimensions (h x w x d) 380 x 300 x 210 mm
weight 12 kg
material 1.4301
remarks * variants
** the suitability of D-RX 250 for the listed ranges depends on the kind of dust and its size distribution.
***The measuring effect is influenced by the stack gas velocity. The influence is compensated.
Subject to technical modifications!

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