Hach 911, User Manual

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49
Sensor Installation
6.2 In-Pipe Ultrasonic Sensor
The in-pipe ultrasonic sensor is used in pipes where level measurement near the top of
the pipe is desired. The sensor reads the level until the liquid reaches the bottom of
the sensor housing. The in-pipe sensor is not recommended for weir or flume applications
due to limited range, but may be desirable in some applications.
6.2.1 Mounting the In-Pipe Sensor
• Mount the sensor over the center of the flow stream where the surface turbulence is
minimized (
Figure 27 on page 50 ).
• Mount the sensor 46 cm (18 in.) away from obstructions located in front of the in-pipe
sensor to prevent inaccurate liquid level readings (
Figure 26 ).
• Level the sensor using the built-in bubble level.
• Ensure the isolation gasket is in place and the mounting bracket thumbscrews are
finger-tight to avoid sensor ringing.
• Install the sensor within 1.5 m (5 ft) of the lowest expected level (the maximum range
of the sensor).
Figure 26 Side View of In-Pipe
1
Pipe Ceiling
5
Internal Deadband (18.3 cm (7.2 inches))
2
Distance from Sensor (Range: 0.2 in. to 5 ft)
6
Pipe Floor
3
45° Deflector
7
Minimum distance to reflecting obstruction (46 cm
(18 in.))
4
Ultrasonic Sensor
8
Reflecting Obstruction