Siemens interranger DPS300 Instructional Manual page 19

Inlet
This is where the wastewater flows into the tank. Do not mount the transducer
close to the inlet because the water is aerated and the sludge is disturbed. To
obtain the most accurate readings, the sensor should be located above a relatively
undisturbed portion of the tank where aeration is not present.
Tank sides
The sensor must be mounted at least 1 m (3') from the side of the tank. If the
sensor is mounted closer than this, the walls could cause interference and
ultimately lead to inaccurate signals or errors.
Ladders, Beams, Supports, etc.
Be sure that there are no underwater obstructions within 1m (3') of the sensor that
could disrupt the signal. Obtain drawings and/or consult with plant personnel to
locate any of these structures that may not be visible.
Surface Skimmers
Skimmers are used to remove the scum from the surface of the water in the
clarifier. They are usually short fences called "flights" that are pulled along the top
of the water with a chain mechanism in rectangular tanks. The scum is skimmed
away from the effluent weirs into a trough where it can be removed easily. It is
important to observe the skimmer action when setting up the InterRanger. If the
best location for the sensor is in the path of the skimmer then the optional
Skimmer Guard must be used.
Rectangular Clarifier
scum
trough
Scrapers
Scrapers keep the oldest sludge on the bottom of the tank from hardening and
help to move the sludge into a hopper for pumping. In rectangular tanks, often the
scrapers are also the skimmers. They run along the bottom on a chain mechanism
for the length of the tank, up the side and then along the top to pull the scum into a
trough.
7ML19981BC01
skimmer direction
flights
mounting location
19
effluent
weir
handrail
InterRanger DPS300