Siemens interranger DPS300 Instructional Manual page 17

Surface Skimmers
Skimmers are used to remove the scum from the surface of the water in the
clarifier. 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 (often the case) then
the optional Skimmer Guard must be used.
Circular Clarifier
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 circular tanks, the skimmer and scraper are often connected to the same
rotating mechanism radiating from the centre of the tank. Common configurations
could include one or two skimmers and up to four scrapers. Usually these arms
are 90° or 180° apart.
7ML19981BC01
handrail
mounting
location
17
skimmer
scum trough
skimmer
direction
bridge
InterRanger DPS300