Design and function
Instruction Manual VisGuard 2 Extractive
14265E/1
17
4.2.2
Sample divider for single sampling
The sample divider is used on sampling systems with long lines (> 30 meters). It is shown in
detail in drawing
KTNPI2-MB
.
The principle of the sample divider is based on the main f low being suctioned in by a suction
fan. A smaller bypass flow – the sample itself – is branched off from this main line and fed
through the measuring cell on the photometer. The pressure conditions inside the sample di-
vider maintain the flow rate through the measuring cell independently. An optional pressure
monitor can be attached to a back pressure nozzle for monitoring the sample flow. Section
5.3.4
The main flow is much greater than the sample flow through the measuring instrument.
Thanks to the high flow velocity, losses and deposits in the suction line can be reduced.
4.2.3
Flow rate monitoring
Figure
3
: Principle of flow rate monitoring
a
Pressure monitor
b
Back pressure nozzle
Pressure monitors (a) are installed in the sampling system for the optional monitoring of the
sample flow. These measure the pressure drop on the back pressure nozzles (b), which are
inserted directly into the sample flow. The integrated signal contact in the pressure monitor
sends a status signal to the control device. Section 5.3.3
The limits on the pressure monitor usually have to be set on site while the system is running.
a
b
+
-
