3.2 Principal units

The gas analytical system in general consists of the following principle units:

• sampling probe with a coarse filter, which is introduced into the pipe or gas duct of a stationary source of emissions;

• heated main pipe for supplying a gas sample from the sampling probe to the input of the gas analyzer;

• pump to convey the gas sample through the gas handling system;

• gas flow rate measurement system, for example a rotameter, to measure the gas flow rate in the gas handling system;

• condensate separator to prevent condensation in the gas handling system;

• fine filter to remove dust from the gas sample, which could cause contamination of various inner parts of the gas analyzer;

• electro-pneumatic valve to switch a sample to be analyzed, a calibration gas mixture or a zero gas to the input of the gas analyzer (a pipe connecting two three-way valves is intended for delivering the CGM to a sampling system through a three-way valve to estimate the absence of probe composition change);

• means for adjusting zero (gas analyzer);

• means for adjusting the gas analyzer by a calibration gas mixture;

• gas analyzer;

• means to check operation of the gas analytical system and means to adjust the units;

• means for data accumulation, processing and storage.

The gas analytical system may include means to signal and record

• the malfunction of the units of the gas analytical system,

• the reduction of the gas amount in a cylinder required for automatic adjustment of the gas analyzer to an amount below the permissible value, and

• the current value of the volume fraction being determined in the sample exceeding the maximum permissible value.