KROHNE PipePatro EN - Manual (Page 10)

2
DEVICE DESCRIPTION
10
PIPEPATROL
www.krohne.com 02/2013 - 4002275001 - MA PipePatrol R01 en
2.4 Leak localisation method
To idendify the source of the leak accuratley the following 3 localisation methods are combined
in PipePatrol.
Under zero leak conditions, pressure drops uniformly along the pipeline. When a leak occurs,
more liquid or gas flows through the pipeline before the leak than after it.
The pressure gradient along the pipeline therefore changes at the leak. The leak localisation can
thus be identified at the point where the gradient changes.
A sudden leak will cause a negative pressure wave in the pipeline, simply because gas or liquid is
leaking out. This pressure wave will travel through the pipeline at the sound velocity of gas or
liquid.
Depending on the localisation of the leak, the pressure wave will arrive at one end of the pipeline
before it arrives at the other. The leak position can be calculated from the difference in the
arrival times at the inlet and outlet.
Gradient Intersection Method
Figure 2-1: Gradient Intersection Method
Wave Propagation Method
Figure 2-2: Wave Propagation Method