Paper Blackening (Pb); Filter Loading (Fl) - TESTO 338 Instruction Manual

3 Specifications
3.4.2.

Paper blackening (PB)

The optical sensor detects the reflection capacity of filter paper
blackened by flue gas. This means that 100% reflection
corresponds to PB = 0 (white paper) and complete absorption = 0%
���� = 10 ∙ ��� −
reflection (completely blackened paper) corresponds to PB = 10.
PB:
R :
B
R :
W
3.4.3.

Filter loading (FL)

Filter loading describes the level of soot on the paper and is
specified in milligrams per square metre. The filter loading
���� = �� ∙ ���� ∙ ��
increases exponentially with the paper blackening.
FL = filter loading
α: empirical, fixed value
PB: Paper blackening
β: empirical, fixed value
12
Measurements are assessed optically and are therefore
dependent on the optical property of the soot. The optical
properties of the soot vary depending on the engine and
fuel, which can lead to inaccuracies during the calculation
of the mass.
�
��
��
��
��
Paper blackening
Measuring value
Reflection of the white filter paper
�� ∙����
Filter smoke number/paper blackening