MultiGas Ultraviolet Modules NDUV

Description

The RITTER »MultiGas« UV sensor is the world’s first gas analysis module based on miniaturized UV-LEDs. The stability and lifetime of these UV-LEDs enables high-precision gas analyses down to the ppm range. By using two UV-LEDs two gases can be detected simultaneously. Furthermore, with this approach measuring ranges from ppm to Vol.-% can be realized.

In the spectral range from 200 nm to 500 nm, nitrogen oxides (NO + NO2), aromatic hydrocarbons, hydrogen sulphide, ozone, sulphur dioxide and chlorine can be reliably detected with this new sensor platform.

The entire unit can be disassembled for easy maintenance/service.

The individual internal modules are sealed by means of O-ring connections.

In order to achieve an optimum adaptation to the required measuring range, the lengths of the modular measurement cells (= cuvettes) can be implemented in the range of 5 mm (large measurement range in percentage level) up to 250 mm (small measurement range in ppm level).

Cuvettes with a length ≥ 20 mm are coated with a resistant gold layer in order to improve the reflection properties for low concentration level detection. Cuvettes used with aggressive gases are gold-coated as well.

The internal mechanical parts are made out of aluminium, optionally out of stainless steel.

For fast response applications the measuring system delivers a stable result within t90 ≈ 1-2 seconds.

Applications

  • Biogas / natural gas analysis
  • Environmental and Process Measurement
  • TOC analysers
  • Continuous Emission Monitoring (CEM)
  • Elemental analysis
  • Industrial gas analysis

Specifications NDUV Sensor

RITTER MultiGas ultraviolet sensor

General features

Measurement technology: Innovative NDUV Sensor
(non-dispersive ultraviolet sensor)
Detectable gases:
O3 CL2 H2S SO2 NO2
Number of simultaneously detectable gases: max. 2
Measurement ranges: See below
Flow rate range: 1 ltr/d ~ 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)
Temperature compensation: Yes
Data acquisition software: Yes
Lifetime of UV radiation source: > 8 000 h
Measurement cuvette: Stainless steel with silicone coating inside
Cuvette sealing: Viton O-ring
Casing: High-quality table-top casing, 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 4mm, Øo 6 mm

Measuring response

Linearity error: < ± 1% F.S.
Repeatability: ± 0.5% F.S.
Long term stability zero N2: < ± 1% F.S. / 24h
Long term stability span: < ± 1% F.S. / month
Temperature influence of zero point: < 1% F.S. / 10K
Temperature influence of span: < 2% F.S. / 10K
Cross sensitivity: < 2% F.S.
Pressure influence: < 1.5% / 10hPa of reading[/wpml-string]
Warm-up time: 1 min (initial), <60 min for full specification
Response time (t90): 1.5 – 15 sec[/wpml-string]
Sampling frequency by software: ≤ 10 Hz
Detection limit: See below
Resolution: 0.5 x detection limit

Electrical features

Power supply: 24 VDC incl. power plug[/wpml-string] 100 ~ 240 VAC / 24 VDC
Supply current (peak[/wpml-string]) <0.4 A
Average power consumption < 7.5 W
Interface: USB (standard), RS232 (option) – incl. data transmission cable 1 m
Analogue voltage output (option[/wpml-string]): 0-2V / 0-5V / 0-10V

Climatic conditions

Operating temperature: +25 ~ +45 °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!

Specifications H2S Sensor

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The H2S sensor works according to the principle of non-dispersive UV absorption (NDUV).

The measuring wavelength used is in the lower nanometer range, which enables inter-ference-free measurements with water vapour and hydrocarbons. This makes the sensor ideal for use in biogas measurements, as accompanying gases such as NH3, CO2, CH4 and H2O do not affect the accuracy of the measurements.

General features

Measurement technology: Innovative NDUV Sensor
(non-dispersive ultraviolet sensor) Dual beam
Detectable gases:
H2S SO2
Number of simultaneously detectable gases: max. 2
Measurement ranges: See below
Flow rate range: 6 ~ 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)
Temperature compensation: Yes
Data acquisition software: Yes
Lifetime of UV radiation source: > 8 000 h
Measurement cuvette: Stainless steel with silicone coating inside
Cuvette sealing: Viton O-ring
Casing: High-quality table-top casing, 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 4mm, Øo 6 mm

Measuring response

Linearity error: < ± 1% F.S.
Repeatability: ± 0.5% F.S.
Long term stability zero N2: < ± 1% F.S. / 24h
Long term stability span: < ± 1% F.S. / month
Temperature influence of zero point: < 1% F.S. / 10K
Temperature influence of span: < 2% F.S. / 10K
Cross sensitivity: < 2% F.S.
Pressure influence: < 1.5% / 10hPa of reading
Warm-up time: 1 min (initial), < 15 min for full specification
Response time (t90): 1.5 – 15 sec
Sampling frequency by software: ≤ 10 Hz
Detection limit: See below
Resolution: 0.5 x detection limit

Electrical features

Power supply: 24 VDC incl. power plug 100 ~ 240 VAC / 24 VDC
Supply current (peak): <0.4 A
Average power consumption: < 7.5 W
Interface: USB (standard), RS232 (option) – incl. data transmission cable 1 m
Analogue voltage output (option): 0-2V / 0-5V / 0-10V

Climatic conditions

Operating temperature: +5 ~ +45 °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!

Specifications UVRAS Sensor

RITTER MultiGas-Modul UVRAS

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).

General features

Measurement technology: Innovative NDIR Sensor (non-dispersive infrared sensor)
Detectable gases:
SO2 NO2 NO
Number of simultaneously detectable gases: max. 3 per sensor unit
Measurement ranges: See below
Flow rate range: 1 ltr/d ~ 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)
Temperature compensation: Yes
Data acquisition software: Yes
Lifetime of IR radiation source: > 40 000 h
Measurement cuvette: Aluminium, with measurement ranges ≤1% gold-plated inside
Cuvette sealing: Viton O-ring
Casing: High-quality table-top casing, aluminium
Dimensions (W x H x L): 171 x 86 x 290 mm
Weight: approx. 2 kg
Gas connections: PVDF screw-type tube connection for tube Øi 4mm, Øo 6 mm

Measuring response

Linearity error: < ± 1% F.S.
Repeatability: ± 0.5 % F.S.
Long term stability zero N2: < 3 ppm / 24h
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 below
Resolution: 0.5 x detection limit

Electrical features

Power supply: 24 VDC incl. power plug 100 ~ 240 VAC / 24 VDC
Supply current (peak): 1.5 A
Inrush current: 0.2 ~ 0.7 A
Power consumption: 36 W
Interface: USB (standard), RS232 (option) – incl. data transmission cable 1 m
Analogue voltage output (option[/wpml-string]): 0-2V / 0-5V / 0-10V

Climatic conditions

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!

Table of Measurement Ranges

Measuring ranges / Full scale value (F.S.)
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
O3
CL2
H2S
SO2
NO2
NO

Infrared module NDIR Ultraviolet module NDUV Ultraviolet module NDUV / UVRAS

* Calibration with Propane

(1) Full Scale (FS)

Other ranges on request

Table of Detection Limits (= 3 σ) in Percent of Full Scale

Detection Limits / % of Full Scale Value (F.S.)
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
O3 < 0.1% < 0.1% < 0.1% < 0.2% < 0.5% < 0.5% < 0.5%
CL2 < 0.1% < 0.1% < 0.1% < 0.1% < 0.1% < 0.1% < 0.1% < 0.2% < 0.5%
H2S < 0.1% < 0.1% < 0.1% < 0.1% < 0.2% < 0.5%
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%

Infrared module NDIR Ultraviolet module NDUV Ultraviolet module NDUV / UVRAS

* Calibration with Propane

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.

1) Zero to Full Scale (FS)

Recalibrations

The following recalibration intervals are recommended for UV sensors:

  • Zero-point:
    • Concentrations < 300 ppm: Every 48 hours with inertgas, e.g. Nitrogen
    • Concentrations ≥ 300 ppm: Every 24 hours with inertgas, e.g. Nitrogen
  • End-point (full scale): Every 3 months with suitable calibration gas