Level Instruments

Chapter from the Vessels & Internals Design Guide.

NAVIGATION

Design P&T Selection	Vessel Sizing	Nozzle Sizing	Level Instruments
Vacuum Vessels	Ceramic Balls	Reference Data

Level Instrument Sizing

Instrument Type	Accuracy (%)	Best For	Installation Notes
Float Switch	±2	Alarm/Control	45° minimum nozzle angle
Capacitive Probe	±1	Continuous	Avoid foam/mist areas
Differential Pressure	±0.5	Exact Level	Calibrate for density
Guided Wave Radar	±0.1	High Accuracy	Needs dry nozzle
Displacer	±0.5	Interface Level	Use for density variation

Installation Requirements:

• Minimum 12" from vessel centerline for level glass

• Isolation ball valves on both connections (safety)

• Sediment trap at lower connection

• Air vent at upper connection for DP cells

Source: Vessels_Internals_Design_Guide_v1.xlsx · sheet “Level Instruments”

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