PPS-M Sample Flowrate in Different Pressure Conditions - Application Note

PPS-M flow configuration

PPS-M sample intake is powered by a choke-stabilized ejector pump, which provides stable sample mass flow in wide range of sampling pressures, if the inlet and outlet probes are in the same pressure (Common mode pressure).

The sensor flow status is determined by three pressures: pump air pressure, inlet pressure and differential pressure between inlet and outlet. Figure 1 clarifies these pressures.

Common mode pressure is the static pressure in exhaust channel and is determined by the exhaust flow and channel resistance. The differential pressure is the pressure difference between the sample inlet and outlet. It is caused by a restriction in the sample flow in inlet or outlet line and the pressure difference between the inlet and outlet. Note that common mode and differential pressures are independent of each other when inlet and outlet are installed in the same channel according to installation instructions.