Hach AV9000, User Manual

Page: 13 / 138

Figure 7 Sensor positions
1 Upstream, facing flow 2 Downstream, facing flow 3 Downstream, reversed
Table 1 Selecting probe direction
Option Description
Upstream Recommended for most applications. The flow stream over the sensor should be as straight
as possible with no drops or turns near the measurement point.
Mount the sensor in the pipe with the beveled edge pointed toward the flow where the flow
stream enters the measurement area.
Downstream Use this option when the sensor is installed downstream of the measurement point (where
the flow stream exits the site). This option is useful when more than one flow stream enters a
site and the combined flow of all streams is measured at a single exit point. This option can
also be used if there are hydraulics preventing the sensor from being mounted in upstream
area.
Mount the sensor facing the flow.
Downstream
(reversed sensor) Use this option when Option B will not work due to poor flow uniformity in the vault. The
maximum velocity read in this kind of installation is 5 fps when the AV9000 interface module
is not used. Mount the sensor in the downstream direction. The manufacturer recommends
verifying the velocity by profiling flow and using a velocity site multiplier, if required, for more
accurate reading.
Note: When the AV9000 interface module and submerged AV sensor are used with the FL900 logger, the
user has the option to select Reversed Sensor on the Sensor Port Set Up menu.
English 13