54
BE 57-660 Eclipse Model 700 Guided Wave Radar Transmitter
3.4.5 Open Channel Flow Capability
Selecting Measurement Type = Flow allows the Model 700
transmitter to measure flow as the Primary Measured Value.
Open channel flow is performed by using the ECLIPSE
Model 700 to measure the Head in a hydraulic structure.
The hydraulic structure is the primary measuring element,
of which the two most common types are weirs and flumes.
Since the primary element has a defined shape and dimen-
sions, the rate of flow through the flume or over the weir is
related to the Head at a specified measurement location.
The ECLIPSE Model 700 is the secondary measuring
device, which measures the Head of the liquid in the flume
or weir. Open channel flow equations stored in the trans-
mitter firmware convert the measured Head into units of
flow (volume/time).
NOTE: Proper positioning of the Model 700 should be per the recom-
mendation of the flume or weir manufacturer.
Open Channel Flow Measurement
Parshall Flume
Flume (side view)
Weir (side view)
Model 700
Flow
Parshall
Flume
Model
700
Water Surface
Throat Section
Flow
Head
Blocking Distance
250 mm (10") min
Re
le
re
nc
e
Di
st
an
ce
Model
700
Water Surface
Relerence
Distance
Head
Crest
Weir Plate
Bl
oc
ki
ng
Di
st
an
ce
Channel Floor
25
0
m
m
(1
0"
) m
in
m
in
im
um
