14
58-610 Model R82 Radar Transmitter
2.4.1.5 Stillwells
The R82 can be mounted in a stillwell but certain consider-
ations should be given:
• Metal stillwells only: 2" (50 mm) Sched 40 max.
• Diameter must be consistent throughout length; no reducers.
• Stillwell length must cover complete range of measurement
(i.e., liquid must be in stillwell).
• Welds should be smooth.
• Vents: holes <0.125" diameter, slots <0.125" width.
• If an isolation valve is used, it must be a full port ball valve
with an I.D. equal to the pipe diameter.
• Bridles/Bypass Installations: The launcher should be rotated
90° from process connections.
• Configuration must include an entry for Stillwell I.D.
See Section 2.6.6.2, Item 34- Stillwell I.D.
2.4.1.6 Open Channel Flow Measurement
For optimal accuracy, mount the transmitter a minimum of
30" above the flow element (this is dependent on type and
size of the flow element). Consult factory for assistance on
this dimension.
Install the Model R82 on the inflow side of the flume throat
or weir crest in the location defined by the manufacturer of
the primary measuring device. The unit should also be
aligned with the longitudinal axis of the flume or weir.
Open channel flow is performed by using the R82 to meas-
ure the level (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 dimensions, the
rate of flow through the flume or over the weir is related to
the liquid level (Head) at a specified measurement location.
The Model R82 is the secondary measuring device which
measures the height (Head) of the liquid in the flume or
weir. Open channel flow equations stored in the R82
firmware convert the measured Head into units of flow
(volume/time).
Figure 14
R82 Mounted in Stillwell (Bridle)
Figure 15
Open Channel Flow Mounting
Model R82
Flow
Parshall
Flume
NOTE:
Proper position of the Model R82
should be per the recommendation of
the flume or weir manufacturer and
meeting minimum height recommen-
dations. Mounting at least 30" above
the top of the element will yield best
accuracy.
