Detector tubes - direct reading colorimetric sampling
analisi dei gas e delle emissioni nel settore navale

analisi dei gas e delle emissioni nel settore navale Detector tubes - direct reading colorimetric sampling

Detector tubes - direct reading colorimetric sampling

Detector tubes - direct reading colorimetric sampling


Detector tubes and manual sampling systems can sample and measure a huge range of substances. These can be sampled using different methods under different conditions.
Standard sampling procedures must be used according to recommendations by reference agencies like BGIA, DFG, NIOSH, OSHA and HSE.

1) Tubes with direct reading colorimetric: the result of the measure is immediately available. No calibration is required. No electrical power is required.
This system has advantages when compared with electronic devices (gas analyzers and monitors) for infrequent tests and when unusual ranges are required.
Working principle: 
The air to be evaluated is drawn through a sampling vial by means of  a pump (a manual pump or an automated system). The substance accumulates on the sensible material inside the vial. The solid media reacts with a characteristic change of colour. The length of the stain or discoloration is an indication of the concentration of the measured substance. The printed scale on the tube allows a direct reading of even small concentrations of gas.
Over 220 available tubes allow the quick measuring of over 500 different gases.

Sampling can be performed with a manual pump (Accuro):








Or by an electronic device automatically dispensing the correct amount of strokes (Dräger X-act® 5000).












2) Sampling Tubes for long-term measurements and lab analysis:
Long-term measurements with diffusion tubes provide integrated measurements that represent the average concentration during the sampling period.
After the sampling is performed, the tubes are normally sent to a lab for analysis, to identify the chemical composition of the sample. 

We can help you in finding the right tube and sampling system. We design and manifacture automated sampling systems, too.






Stand-alone automatic sampling systems

To detect organic compounds it is advisable to perform long-term measurements (e.g. 30 minutes) with diffusion tubes at low flowrate (e.g. 0,2 l/min). 

An automated sampling system with proper timings and streams selection can be used. A box containing all the parts (sampling pumps, flow meter, valves, sampling tubes with a convenient holding rig, etc.). 

This system was recently installed at a chemical plant in North-West Italy, to monitor potentially dangerous emissions.
Dräger activated Charcoal Type tubes are being used to collect the sample and to enable later determination of its composition.
This custom-made automated sampling box also includes a heating system to allow operation in a low temperature environment.
All stream-handling components are made of PVDF given the corrosive nature of some components of the sampled stream (Chlorinated aromatic compounds, Aromatic Hydrocarbon, HCL, Chlorine).

The tubes chosen for this application are Dräger Activated Charcoal Tube Type G.