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6.2.2 Booster system for tank-filling applications
The booster system for tank-filling applications is designed to fill
a tank such as a roof tank or a break tank in a controlled manner.
The booster system controls the filling either via level switches, a
level sensor, or a ball cock valve.
•
Operating principle
The system has three methods of operation, one based on
level switches, one based on a level sensor and the other
based on a ball cock valve.
•
Operation with level switches
The user adjusts the switches in the tank to the desired stop
and start levels.
•
Operation with level sensor
The user adjusts the setpoint so it corresponds to the real tank
height, measured from the bottom of the tank to the top, via
the user interface of the CU 323 control unit.
The Multi-B systems configured for tank filling applications work as described below.
E: Two to three electronically speed-controlled pumps
Pump speed
n
100 %
70 %
First pump starts
Fig. 7
Example of tank filling
•
In tank-filling applications, the booster system fills the tank with focus on protecting the piping and preventing water hammer. When
low level in the tank is reached, a speed-controlled pump starts by running approximately 70 % of maximum speed to slowly and
safely fill the pipes. After a while, it increases the speed to 100 %, and the next pump is started. When the tank is full, the pumps
stop.
•
Systems with more than two pumps will as default set one pump as standby pump.
•
Changeover among the mains-operated pumps is automatic and depends on load, time and fault.
8
Control variant E
Second pump starts
First pump stops
The CU323 will display the tank level graphically. For
assistance contact Grundfos.
•
Operation with ball cock valve
The user adjusts the ball cock valve in the tank to the desired
start and stop levels.
•
Factory setting
Start level: 15 % of setpoint
Stop level: 85 % of setpoint
High-level alarm: 95 % of setpoint.
The PC tool is required to adjust the start and stop
level setting. For assistance contact Grundfos.
Time
t
Second pump stops
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