KM 2000 CnHm EM

Hydrocarbon Analyser
KM 2000 CnHm EM


The modular constructed ADOS KM 2000 CnHm EM equipment incorporates a microcontroller-aided measurement device for measuring solvents. All combustible gaseous CnHm compounds can be measured with the exception of chlorinated and sulphur-sublimed hydrocarbons.

The thermocouples used for measurements, in conjunction with applying the principle of heat reaction, offer the following advantages:

  • High degree of sensitivity
  • Good accuracy
  • Negligible drift of zero point
  • Over-range signals have no effect

Fields of Application

Supervision of industrial processes

  • KM 2000 CnHm EM:
    Measuring the emission of hydrocarbons, according to the German clean-air regulations
  • KM 2000 CnHm:
    Measuring solvent saturation
    Measuring the concentration of solvents

Room air (ventilation) monitoring
A warning is issued at very low concentrations of poisonous gas thus preventing any danger to health.

1= Sampled gas intake
2= Test gas intake
3= Prefilter or compensating filter
4= Sampled gas pump
5= Flow regulator
6= Flow-through meter
7= Flow monitor
8= Heating coil
9= Catalyst chamber
10= Reference measuring point
11= Measuring point
12= Reaction chamber
13= Measuring amplifier
14= Limit monitor 1-4
15= Measured value integration
16= Continuous-line recorder
17= Concentration indicator
18= Heater
19= Temperature Control
20= Resistance-thermometer
21= Gas outlet
22= Inert mass
23= Catalytic converter

Measurement Principle and Function

Gas measurement system
The sampled gas is drawn in by a pump through a feed pipe (heated if required), to the reaction chamber, via a compensating filter, flow regulator and flow-through meter. The gas is warmed to a constant temperature by means of the heater coil and jacket and finally burned in a solid-matter catalytic converter. The difference in temperature before and after combustion, is used as the measurement signal that is prepared and evaluated by the microcontroller-aided analyser.


The analyser functions on the principle of heat reaction.The difference in temperatures at the reference measuring point and the measuring point, is a directly-dependent variable of the component part of combustible substances in the gas. The reference measuring point is subjected to the heated non-burned gas mixture, whilst the second probe of the thermocouple pile measures the temperature of the burned gas. A load-independent current of 0-(4)-20 mA is available for connection to electric test meters, plotters and limit value monitors. An RS 232 interface is incorporated for data communication.

The inclusion of a measured value integration provides the facility of forming the average value of measured quantities, continuously or over a prescribed period of time.

Equipment Construction

The hydrocarbon measuring system ADOS KM 2000 CnHm EM consists of the following 19" rack units:

  • Reaction chamber with sensor and electronics
  • Gas suction system with or without constant heating for the feed pipes, with sampled gas pump, flow-through meter, flow regulator, flow monitor and filter.
  • Microcontroller-aided evaluation unit in 19"-system with application specific standard plug-in Euro-cards
  • Housing


  • CnHm EM sampling probes heated or unheated
  • Mounting flanges for removal of heated extraction pipes
  • Heated extraction pipes
  • Test gas bottles with pressure reducer
  • Pollution control computer EUR 196 according to the clean-air regulations
  • Continuous-line recorder
  • Air purging system
  • Compensation of CO cross-sensitivity
  • Automatic calibration system

Note: tested and approved according to the guidelines of the Clean Air Act in 2002, meets the requirements of QAL 1 according to DIN EN14181: 2004

Technical data

Measurement principle: Measuring the heat of combustion in a catalytic converter
Measuring ranges: 0 - 50 mg C/m3 TOC up to 0 - 1600 g/m3 TOC
Minimum detection limit: 1 mg C/mTOC
Cross sensitivity
(50 mg/mmeasuring range):
concentration: max. deviation:
200 mg/m3 SO2 -10 %
30 mg/m3 NO2 -2,5 %
300 mg/m3 CO +108 %
300 mg/m3 NO +7 %
Output signals: Current interface 0-(4)-20 mA
max. load 400 ohm; RS 232
Response time (t90): < 200 sec. sampling pipe (approx. 36.09 ft; dead time 10 sec.)
Accuracy: < 2 % full-scale error
Permissible ambient temperature: +41 °F to +104 °F
Temperature dependency: < 5 % full-scale error
Sampled gas flow: 125 l (±10 l / h)
Preheating time: approx. 120 min.
Maintenance interval: 4 weeks with auto-calibration
1 week without auto-calibration
Mains supply: 115 V / 60 Hz; 230 V / 50 Hz; 600 VA
Dimensions (W x H x D): 23.6 x 18.8 x 19.7 inch
Weight: approx. 94.79 lbs
Test certificate: TÜV approval according to the clean-air regulations ("TA-Luft");
TÜV-report: 936 / 21 200 245