RITTER · Ultraviolet Module NDUV / UVRAS

Table of Contents

1 Description
2 Applications
3 Specifications
4 List of standard measurement ranges *1 ( and detection limits *2 )
5 Recalibrations

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 Ø_i 4 mm, Ø_o 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. 2024-09-04 / Subject to alterations.

The most recent version of this data-sheet can be found at …
https://www.ritter.de/en/data-sheets/ultraviolet-module-nduv-uvras/

Dr.-Ing. RITTER Apparatebau GmbH & Co. KG · Coloniastrasse 19-23 · D-44892 Bochum · Germany
For questions please contact mailbox@ritter.de or your local distribution partner (on our overview page)