Boiler house Level controls
2
Examples of the many level control duties possible (continued)
Control valve
LCR2250 controller
LP21 probe/ PA420 preamplifier
Make-up water
High level alarm
2.3 4
Fig. 3 Process water tank with modulating fill control, and high level alarm
Valve modulates to maintain water level within this band
Flow to process
LCR2250 controller
LP21 probe/ PA420 preamplifier
Fig. 4 Drainage control of a large process pressure vessel; modulating control with high level alarm
Control valve
High level alarm
Valve modulates to maintain water level within this band
To drain
AI-P693-31 EMM Issue 1
Tank Level Control (On/Off or Modulating) using Capacitance Probes
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