Measuring unit for analysing gas components or aerosols

摘要

The vacuum pump (5) sucks in the gas to be measured. A calibrated gas supply line and a changeover valve are provided, so that a changeover can be made between the measurement gas supply and the supply of the calibrated gas. The changeover valve (3) is arranged outside the hot section of the measuring unit, and the gas supply is thereby applied over the gas supply capillaries that in the calibrating mode, the flow through the sensor (1) is in a reverse direction compared to the flow in the measuring mode.