Flow Application Example; Parshall Flume - Siemens SITRANS L 7ML5400 Operating Instructions Manual

Commissioning
6.8 Application examples
Quick Start Parameter
Transducer
Operation
Temperature Source
Units
High Calibration Point
Low Calibration Point
Response Rate
see Fill Rate per Minute (2.3.1.) (Page 178)
1)
The application is a vessel that takes an average 3 hours (180 minutes) to fill and 3 weeks to
empty.
Fill rate = (Low calibration point – High calibration point ) / fastest of fill or empty time
= (15.5 m – 1 m) / 180 min.
= 14.5 m /180 min. = 0.08 m/min.
6.8.2

Flow application example

6.8.2.1

Parshall Flume

In this example, a 12 inch (0.305 m) Parshall Flume has been installed in an open channel.
As per the supplier's data sheet, the device has been rated for a maximum flow of 1143
m per hour at a maximum head of 0.6 m.
3
The Parshall Flume is considered an exponential device, therefore the supplier's data sheet
includes a flow exponent value of 1.522.
The SITRANS LUT400, and the XRS-5 transducer have been installed 1.6 m above the channel
beside the TS-3 external temperature sensor.
During intermittent peak flow times, the head level can be expected to rise at a rate of
approximately 0.12 m/minute. The application also calls for a flow sampler to be activated
every 1000 m
the event of a loss of echo or cable fault.
80
Setting
XPS-15
LEVEL
TS-3
M
1.0
15.0
SLOW
, or 24 hours (whichever comes first), and for a fail-safe alarm to activate in
3
Description
Transducer to be used with the LUT400.
Material level referenced from Low Cal. Point.
Temperature source.
Sensor measurement units.
Process full level.
Process empty level.
Sets Fill Rate / Empty Rate to 0.1 m/minute.
1
Operating Instructions, 04/2021, A5E33329501-AG
SITRANS LUT400