The engineering task
A liquid is transferred from a source vessel through piping, fittings, exchanger and control valve to a destination vessel. Levels and operating pressures vary, creating a band of system curves rather than one pressure drop.
The pump must meet the maximum duty without operating too far right or left on its curve at minimum duty. NPSH, minimum flow, valve authority and surge following rapid closure are as important as normal operation.
Required design data
- Minimum, normal and maximum flow
- Levels and pressures in both vessels
- Pipe lengths, diameters, roughness and fittings
- Pump curve, vapour pressure and closure times
Technical solution approach
Define operating cases
Determine static pressure difference and elevation head for all combinations of vessel level and pressure.
Calculate the network
Combine pipe friction and local losses over flow rate to form the system curve.
Select the pump
Check operating points, efficiency, power, minimum flow and specific speed.
Check suction and control
Compare available and required NPSH; assign sufficient but not excessive pressure drop to the control valve.
Assess transients
Evaluate rapid valve closure, pump trip and reverse flow for maximum and minimum pressure.
Expected deliverables
Suitable SOL ALPHA modules
The modules form a technically plausible toolchain. Their final selection and sequence will be confirmed during the later calculation against the applicable code and project conditions.