How to choose a SF6 gas analyzer

How to choose a sulfur hexafluoride gas analyzer

Product Introduction Comparison of Four SF6 gas analyzer

1.WIKA GA11

2.DILO 3-038R-R403

3.Rapidox SF6 6100

4.SF6Relations RA912F

1.WIKA GA11  

Applications of the SF6 Gas analyzer

• Analysis of the gas quality in gas-filled equipment

• For the analysis of SF6 gas, g3 gas or N2 gas

Special features of the SF6 Gas analyzer

• Provides measured values for humidity, gas composition (purity) and decomposition products (optional)

• Low transport weight of 25 kg

• Three methods for emission-free treatment of the measurement gas:
  - Direct pumping back into the tested compartment
  - Pumping into an external gas cylinder
  - Collecting in an external gas bag

• Battery power for min. 5 measurements or mains supply

• Not compromised by transport restrictions (IATA)

Inlet/return pumps 1.3 ... 35 bar abs./1.3 ... 10 bar abs. 

Outlet for gas cylinder 1.3 ... 10 bar abs. 

Outlet for gas recovery bag < 1.015 bar abs.

SF₆ percentage sensor 

Measurement principle Sound velocity 

Measuring range/accuracy 0 ... 100 % ±0.5 % based on SF₆/N₂ mixtures (calibration for SF₆/CF₄ mixtures on request) 

Resolution 0.1 %

Humidity sensor 

Measurement principle Polymer-based capacitive humidity sensor 

Measuring range/accuracy -40 ... +20 °C dew point ±2 °C 

                 dew point -60 ... < -40 °C dew point ±4 °C dew point 

Resolution 1 °C

SO₂ sensor 

Measurement principle Electrochemical SO₂ sensor 

Measuring range/accuracy In combination with HF sensor, only 0 … 10 or 0 … 20 ppmv make sense. 

■ 0 ... 10 ppmv ±0.5 ppmv 

■ 0 ... 20 ppmv ±1 ppmv 

■ 0 ... 100 ppmv ±3 ppmv 

■ 0 ... 500 ppmv ±5 ppmv 

Resolution 0.1 ppmv 

Service life 2 years starting from installation

H₂S sensor 

Measurement principle Electrochemical H₂S sensor 

Measuring range/accuracy 0 ... 100 ppmv ±5 ppmv 

Resolution 0.1 ppmv

Service life 2 years starting from installation

CO sensor 

Measurement principle Electrochemical CO sensor 

Measuring range/accuracy 0 ... 500 ppmv ±9 ppmv 

Resolution 0.1 ppmv

Service life 2 years starting from installation

Here's the sensor information presented in a table format:

Sensor	Measurement Principle	Measuring Range/Accuracy	Resolution	Service Life
SF₆ percentage	Sound velocity	0 … 100% ±0.5% based on SF₆/N₂ mixtures (calibration for SF₆/CF₄ mixtures on request)	0.1%	2 years starting from installation
Humidity	Polymer-based capacitive humidity sensor	-40 … +20°C dew point ±2°C dew point<br>-60 … < -40°C dew point ±4°C dew point	1°C	-
SO₂	Electrochemical SO₂ sensor	0 … 10 ppmv ±0.5 ppmv 0 … 20 ppmv ±1 ppmv 0 … 100 ppmv ±3 ppmv 0 … 500 ppmv ±5 ppmv	0.1 ppmv	2 years starting from installation
H₂S	Electrochemical H₂S sensor	0 … 100 ppmv ±5 ppmv	0.1 ppmv	2 years starting from installation
CO	Electrochemical CO sensor	0 … 500 ppmv ±9 ppmv	0.1 ppmv	2 years starting from installation

2.DILO 3-038R-R…

DILO 3-038R-R…  Selection Table

Device Type	Measurement Capabilities	Range/Specifications	Model
Single measuring	Percentage Measurement	0 - 100 vol.-%	R101
Single measuring	Moisture Measurement	-76 °F to 68 °F (-60 °C to +20 °C) dew point	R102
Two-in-one measuring	Percentage and Moisture Measurement		R201
Three-in-one measuring	Percentage, Moisture, and SO2 Measurement	0 - 20 ppm SO2	R301
Three-in-one measuring	Percentage, Moisture, and SO2 Measurement	0 - 100 ppm SO2	R302
Three-in-one measuring	Percentage, Moisture, and SO2 Measurement	0 - 500 ppm SO2	R303
Four-in-one measuring	Percentage, Moisture, SO2, and HF Measurement	0 - 20 ppm SO2, 0 - 10 ppm HF	R401
Four-in-one measuring	Percentage, Moisture, SO2, and HF Measurement	0 - 100 ppm SO2, 0 - 10 ppm HF	R402
Four-in-one measuring	Percentage, Moisture, SO2, and HF Measurement	0 - 500 ppm SO2, 0 - 10 ppm HF	R403
Six-in-one measuring	Percentage, Moisture, SO2, HF, H2S, and CO Measurement	0 - 100 ppm SO2, 0 - 10 ppm HF, 0 – 100 ppm H2S, 0 – 500 ppm CO	R602

Sensor	Measuring Principle	Measuring Range	Measuring Accuracy	Adjustable Limit Value	Recommended Calibration Interval
Purity	Velocity of Sound	0–100 % vol	±0.5% vol	0-100% vol	2 years
Moisture	Electronic Dew Point Measurement (Capacitive)	-60 to +20°C	±2 °C (> -40 °C), ±3 °C (< -40 °C)	-60 to +20 °C	2 years
SO2	Electrochemical Reaction	0 – 20ppm,  0 –100ppm,  0– 500ppm	< ±2% of Measuring Range	0 – 20 ppm	2 years (lifetime)
CO Option	Electrochemical Reaction	0 – 500ppm	< ±2% of Measuring Range	0 – 500 ppm	2 years (lifetime)
HF Option	Electrochemical Reaction	0–10 ppm	< ±10% of Measuring Range	0 – 10ppm	2 years (lifetime)
H2s Option	Electrochemical Reaction	0–100 ppm	< ±2% of Measuring Range	0–100ppm	2 years (lifetime)

3.Rapidox SF6 6100

The Rapidox SF6 6100 Portable is designed for controlling and monitoring the quality of SF6 in MV & HV gas insulated electrical equipment. Exceptional accuracy and stability are provided when measuring the purity of SF6 gas, through specially selected sensors. A gas output nozzle allows for the analyser to be attached to the Rapidox Gas Recovery Bag, ensuring that all sampled SF6 gas is recovered.

Sensor	Specification	Accuracy	Calibration	Lifespan	Sensor Type
SF6 (Sulphur Hexafluoride)	0-100%	±0.5% accuracy	Every 12 months	>5 years	Infrared (IR)
H2O (Dew Point)	-60°C to +20°Cdp (10 – 24,000ppmV)	±2°Cdp of reading	Every 12 months by Sensor Exchange	2-3 years	Polymer
SO2 (Sulphur Dioxide)	0-100ppm OR 0-500ppm	±2% full-scale	Every 12 months	2-3 years	Electrochemical
HF (Hydrogen Fluoride)	0-10ppm OR 0-30ppm	±2% full-scale	Every 12 months (Using HCI gas)	2-3 years	Electrochemical
CF4* (Tetrafluoromethane)	0-80%	±1% of full reading	N/A	N/A	(measured by balance of SF6 + Air reading)
H2S (Hydrogen Sulphide)	0-100ppm	±2% full-scale	Every 12 months	2-3 years	Electrochemical
CO (Carbon Monoxide)	0-1,000ppm	±2% full-scale	Every 12 months	2-3 years	Electrochemical
O2 (Air) / N2 (Nitrogen)	0-100%	full-scale based on oxygen component	Every 12 months	2-3 years	Electrochemical O2 scaled to read as Air or Nitrogen

4.SF6Relations RA912F

The RA912F multi-functional SF6 Gas analyzer allows the determination of up to 6 quality parameters with only one measurement

SF6 concentration (%)

Moisture concentration (Dew Point）

SO2 concentration (ppmv)

CO concentration (ppmv)

H2S concentration (ppmv)

Option: HF concentration (ppmv)

RA-912F SF6 Multi-Analyzer measures SF6 purity based on the principle of thermal conductivity. Its unique spectral band absorption characteristics accurately identify SF6, effectively reducing interference from other components, making it suitable for electrical equipment filled with SF6 and gases like N2 or CF4. The device features an advanced cross-sensitivity decomposition algorithm, built upon extensive laboratory data and incorporating linear algebra for enhanced accuracy. Additionally, it employs the classic polymer film method for measuring SF6 humidity. Changes in 

ambient humidity alter the dielectric constant of moisture-sensitive components, thereby causing changes in the output electrical signal.

RA912FP  

Besides having the same features as the RA912. RA912FP has a fully automatic SF6 analyzer designed 

to meet zero emissions,After measurement, the gas can be pumped back in the original way.

Technical Data

Dimensions: L 406 mm, W 538 mm, H 269 mm

Weight: 15 kg

Input Pressure: 0.2 - 35 bar

Operating Temperature: -20 °C to +50 °C

Ambient Moisture: 15% up to 90% relative moisture, non-condensing during operation

Operating Voltage: 100-240 VAC, 50/60Hz

Number of Measured Values to be Stored: Max. 500

Interface: USB

Parameter	Purity	Moisture	SO2	H2S	CO
Measuring Principle	Thermal conductivity	Electronic moisture measurement (capacitive)	Electrochemical reaction	Electrochemical reaction	Electrochemical reaction
Measuring Range	0 - 100 vol.%	-80 to +20 °C	0 to 100 ppm	0 to 10 ppm	0 to 500 ppm
Measuring Accuracy	±0.5 % (F.S)	±2 °C	±5 % μL/L	±5 % μL/L	±5 % μL/L
Flow Rate	250 to 350 mL/min Recommend 300 mL/min	300 to 900 mL/min Recommend 500 mL/min	100 to 120 mL/min Recommend 100 mL/min	100 to 120 mL/min Recommend 100 mL/min	100 to 120 mL/min Recommend 100 mL/min
Reaction Time	< 30 s	< 3 min	< 60 s	< 60 s	< 60 s
Recommended Calibration Interval	every one year	every one year	every one year	every one year	every one year