ADVANCED AUTOMATION LOWERS LABOR COST AND IMPROVES PERFORMANCE
over crushed gravel. Each tank is separated
into two compartments, for a total of four
individual cells.
The two cells in each tank share a common
collector pipe, backwash supply valve, and
effluent discharge valve. There are a total
of 14 such assemblies, in different sizes, for
managing the flow of water and air through
the filter cells. The valve shown in Figure
1: is used to introduce air into the tank for
pre-backwash agitation of filter media (air-
scouring). By utilizing the air scour system
the wash time was reduced 30%.
Figure 2: offers a close up of three different
AWWA valve assemblies. All process valves,
actuators, and limit switch assemblies were
supplied by Festo.
The effluent discharge valve operates
proportionally with the help of a pneumatic
proportional positioning valve and position
feedback unit. This system allows the
operators to set the desired flow rate. A
magnetic flow meter provides feedback to
the PLC, which uses a PID flow control loop
to modulate this valve. There are two such
valves in this system. Festo pre-assembled
all process valve assemblies prior to shipment
to Las Palmas.
The Whole System Graphically
Presented on the Operator Screen
The Process Overview screen is the main
control point for the filtration system.
The overview screen provides a complete
view of the entire process as a graphical
representation with real-time instrument data,
graphical animations, and touch-sensitive
areas that are used for showing an item in
more detail. For example, touching any of
the valve, filter, or pump symbols changes the
displayed page to one dedicated to the device.
Figure 4. Plant Overview. Control Panel, Process Valve Assy. & Filter Cells.
Figure 3. HMI Screen — System Process Overview
|
0 9 / 1 3
22
airbestpractices
.com
SUSTAINABLE MANUFACTURING FEATURES
1,2,3 5,6,7