DTC-HS34 H2S Analyser

Measures H2S in continuous flowing and pressurized gaseous streams.

DTC-HS34 H2S Analyser
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Duty: To measure the concentration of H2S in a process gas stream.

The principle of operation is as follows. A reel of paper tape impregnated with lead acetate is exposed to the gaseous process sample in the sample chamber. Hydrogen sulphide (H2S) in the process sample reacts with the lead acetate, after acidification, to form lead sulphide (PbS), a brown compound that stains the tape. The higher the concentration of H2S the darker the stain. A focused LED and single photo detector system continuously measures the darkening stain and the analyser reports this as a 4-20mA output of the concentration of H2S.

Incremental measurements are made on the same spot until saturation occurs, when the tape is advanced to a fresh portion of tape. This reduces tape usage and avoids the need for frequent zero or span calibrations.

The benefits of this technology can be summarised as follows:


  • As the measurement is specific to H2S, there will be no interference from other sulphur components
  • A continuous analyser with response times as low as 10 seconds
  • The instrument has a wide range capability, measuring between 0-5ppm to 0-50% H2S
  • Configuration of the system is via a touch screen which eliminates the need to open the enclosure.
  • All Electronic tuning carried out from GUI, removing the need to open up enclosure while analyser is powered up
  • Single point calibration results in lower running costs
  • Suitable for gas group IIB + Hydrogen environment
  • Average tape life 30 days.
  • RS-485 Modbus capability.

With its wide-ranging ability to measure H2S from % levels down to ppb levels, the HG400 range of H2S process analysers can be utilised in many process industries, including:


  • Natural Gas pipelines
  • Reformer recycle gas
  • Offshore gas production
  • Fuel gas monitoring
  • Sour gas treatment plants
  • Gas processing
  • Biogas





Measurement principle 



Measurement range 


0-5, 0-50, 0-300, 0-5000 ppm to 0-50%

Typical ranges


0-5 ppm 



0-50, 0-300, 0-5000 ppm to 0-100%



± 1%

Response time


< 60 seconds






2 x measurement alarm



1 x instrument failure alarm

Area classification 


ATEX approved, Zone 1

Ambient temperature 


0°C to +50°C 

Tape life 


Up to 30 days depending on application.






110 / 240 VAC 50 / 60 Hz 9 - 36 VDC

Process sample 


1 barg 



Flow rate 0.15 to 0.3 l/min




Process connections 


⅛” OD inlet, ¼” NPT female vent 

Analyser vent 


To Atmospheric, no back pressure



45 Kg



381(w), 1219(h), 242(d) mm