SYSTEM OPERATION IN SERVICE
(SYSTEM 14-DEMAND)
The system operates as part of a multi-tank regeneration
system. This example applies to either a 2, 3 or 4 tank system.
Each tank in the system will have an active flow meter input,
even in Standby.
The number of tanks In Service depends on the flow rate.
Examples of a Four-Unit System:
1.
One Tank is In Service at all times (the "primary tank").
In Service
(Primary Tank)
Standby
1
2
3
4
2.
The total flow rate to the primary tank increased past the
first trip point programmed rate. The flow stayed past
the trip point delayed time. The next tank (least volume
remaining) changes from Standby to In Service. This then
splits the total flow between two meters.
In Service
1
2
3
4
Standby
First Trip Point
(Primary Valve)
Total Flow Split
Between Two Meters
3.
The flow rate demand decreased below the first trip point.
The tank returns to Standby.
Standby
Flow Rate Demand
Below First Trip Point
(Primary Valve)
1
2
3
4
4.
Total flow rate demand increased past a second trip point
programmed rate. The second and third tank (least volume
remaining) changes from Standby to In Service. The total
flow is split between the three meters.
Standby
Flow Split Between
Three Meters
1
2
3
4
5.
The third tank returns to Standby as demand decreases
past the second trip point.
Standby
Flow Split Between
Two Meters
1
2
3
4
6.
Tanks return to Standby due to decreased total flow rate
and trip points programmed. The tank with the most
remaining volume will be the first to go into Standby.
Full Capacity
4th in Standby
(Primary Valve)
3/4 Capacity
3rd in Standby
1
2
3
4
1/2 Capacity
2nd in Standby
1/4 Capacity
1st in Standby
7.
The primary tank regenerates. The next tank with the least
remaining volume becomes the new primary tank. The tank
with the next least volume remaining will be the first trip
point programmed rate. Tanks continue operating in this
order.
Full Capacity
4th in Standby
3/4 Capacity
3rd in Standby
1
2
3
4
1/2 Capacity
First Trip Point
Programmed Rate
1/4 Capacity
New Primary Tank
System Operation in Regeneration:
If two tanks are In Service and both reach
Volume Remaining = 0, the other two tanks will shift from
Standby to In Service. The lead tank with
Volume Remaining = 0 will start Regeneration. The second
tank with Volume Remaining = 0 will enter Standby. If flow
increases past the trip point a third tank needs to enter In
Service. The tank in Standby with Volume Remaining = 0 will
shift into In Service to maintain a steady flow. Operating for
extended periods in this mode may degrade the water quality.
4 • NXT Stager Controller FE11