RITTER »MultiGas« Ultraviolet Module NDUV / UVRAS

Table of Contents

Description

For the detection of NO an EDL (electrodeless gas discharge lamp) is used. In the EDL, N2 and O2 are converted to NO and produce a selective UV radiation. With this radiation, a cross-sensitivity-free NO measurement is made possible. This method is called UV resonance absorption spectroscopy (UVRAS). A combination of both the UVRAS and NDUV technology allows the simultaneous gas analysis of NO, NO2 and SO2 in the lower ppm range which is particularly important in flue gas analysis (Continuous Emission Monitoring, CEM).

Applications

  • Automotive test equipment
  • Portable Gas Analysis (PEMS)
  • Exhaust gas monitoring (CEM)
  • Laboratory area
  • Industrial gas analysis
  • Continuous Emission Monitoring (CEM)
  • Automotive exhaust gas analysis

Specifications

General features
Measurement technology: UV resonance absorption spectroscopy (UVRAS)
Detectable gases: 
SO2 NO2 NO
Number of simultaneously detectable gases: max. 3 per sensor unit
Measurement ranges:See Table of Measurement Ranges
Flow rate range: 5 ~ 300 ltr/h
For higher flow rates the sensor can be operated in bypass
Max. gas inlet pressure:300 mbar
Pressure loss (without additional optional sensors): 10 @ 100 / 35 @ 200 / 70 @ 300 (mbar @ ltr/h)
Additional heated and thermostatted enclosure inside of sensor casing:Yes
Temperature compensation:Yes
Data acquisition software: Yes
Lifetime of UV radiation sources:LED > 20 000 h (NO2, SO2)
EDL > 8 000 h (NO)
Measurement cuvette:Stainless steel with silicone coating inside
Cuvette sealing:Viton O-ring
Internal tubing:FKM / Viton (fluorinated rubber)
Casing: High-quality table-top casing type 2, aluminium
Dimensions (W x H x L): 464 x 189 x 305 mm
Weight: approx. 6.5+ kg
Gas connections: PVDF screw-type tube connection for tube Øi 4 mm, Øo 6 mm
Measurement data
Linearity error: < ± 1% F.S.
Repeatability: ± 0.5 % F.S.
Long term stability zero: < 3 ppm / 24 h
Long term stability span: < ± 1 % F.S. / month
Temperature influence of zero point: < 1 % F.S. / 10 K
Temperature influence of span: < 2 % F.S. / 10 K
Cross sensitivity: 500 ppm NO2 < 2 ppm
100 ppm SO2 < 2 ppm
100 ppm N2O < 10 ppm
20 °C D.P. H2O < 10 ppm
Pressure influence:  < 1.5% / 10 hPa of reading
Warm-up time:  1 min (initial), < 60 min for full specification
Response time (t90):  1.5 ~ 15 sec
Sampling frequency by software:  ≤ 10 Hz
Detection limit:  See Table of Measurement Ranges
Resolution:  0.5 x detection limit
Electrical features
Power supply: 24 VDC incl. power plug 100 ~ 240 VAC
50/60 Hz: 24 VDC
Supply current (peak): 1.5 A
Inrush current: 0.2 ~ 0.7 A
Power consumption: 36 W
Interface: USB (standard)
RS232 / CANbus / CANopen (options)
incl. data transmission cable 1 m
Analogue voltage output (option): 0-2 V / 0-5 V / 0-10 V
Gas parameters
Operating temperature:+5 ~ +40 °C
Storage temperature: –20 ~ +60 °C
Operating pressure: 800 ~ 1200 hPa (mbar)
Ambient humidity:0 ~ 95% rel. humidity
Condensing inside of sensor must be prevented!

List of standard measurement ranges *1 ( and detection limits *2 )

Standard Measuring Ranges with respective Detection Limits ( % of F.S. *3 )
100
Vol.%
50
Vol.%
30
Vol.%
20
Vol.%
10
Vol.%
5
Vol.%
1
Vol.%
5,000
ppm
2,000
ppm
1,000
ppm
500
ppm
300
ppm
100
ppm
50
ppm
10
ppm
1
ppm
SO2
(< 0.1%)

(< 0.1%)

(< 0.1%)

(< 0.1%)

(< 0.1%)

(< 0.1%)

(< 0.1%)

(< 0.1%)

(< 0.5%)

(< 0.5%)

(< 0.5%)
NO2
(< 0.1%)

(< 0.1%)

(< 0.1%)

(< 0.2%)

(< 0.2%)

(< 0.5%)

(< 0.5%)

(< 0.5%)
NO
(< 0.1%)

(< 0.1%)

(< 0.1%)

(< 0.2%)

(< 0.2%)
*1 A standard measurement range is defined by / *2  (= 3 σ) in Percent of Full Scale / *3 F.S. = Full Scale / *4 Calibration with Propane

Infrared module NDIR Ultraviolet module NDUV

Definition of Detection Limit

The Detection Limit is the smallest measurement value which can be obtained with a specific uncertainty. This uncertainty includes the resolution, noise and stability of the gas sensor for a specific gas and specific measurement range. For evaluation of the detection limit value, several single measurements are taken at the identical measurement conditions. With the obtained single measurement results the standard deviation “Sigma” (σ) is calculated. The values given in the table equal the triple amount of Sigma.

Recalibrations

The following recalibration intervals are recommended for UV sensors:

  • Zero-point:
    • Concentrations < 300 ppm: Every 48 hours with inert gas, e.g. Nitrogen
    • Concentrations ≥ 300 ppm: Every 24 hours with inert gas, e.g. Nitrogen
      The recalibration of the zero point is described in the software manual.
  • End-point (full scale): Every 3 months with suitable calibration gas

V 1.0 / Rev. 2024-07-03 / Subject to alterations.