Endress+Hauser ASP Station 2000 Zusatzbeschreibung Seite 10

ASP Station 2000
Definition:
Flow proportional sampling
Construction and function of
the dosing system
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1. System description
In flow proportional sampling samples with varying sample volumes are taken
in fixed presettable time cycles. The sample volume is dependent on the actu-
al flow rate. This results in varying sample volumes in fixed time cycles (see
fig. 1).
In the dosing system there is a fixed, vertical slotted tube and a revolving tube
with a helical slot (see figure) . By revolving this tube the position of the
opening and therefore the dosing volume is changed.
Changing the sample volume is done using a motor that is set up in the set-
ting up sequences. The sample volume cannot be manually changed.
At the beginning of a sampling sequence the actual flow rate is interrogated
and the respective sample volume is set during the purge phase.
In addition to flow proportional sampling both time and quantity proportional
sampling can be realised.
2. Electrical connection
In order for flow proportional sampling to be done effectively a flow measure-
ment that can transmit an analogue signal to the sampler is necessary. This si-
gnal is connected to the analogue input X1 (see standard operating manual).
Flow proportional sampling