Hydraulic design: valves, pipelines and system operation

The hydraulic design of the pumping system includes the following aspects:

• Calculation of pump head and flow
  
• System resistance curve
• NPSH calculations
• Suction pipe design,
• Discharge pipe size
• Rising main to discharge point
• Valves such as isolating valves, non-return valves and control valves
• System design pressures
• Pipeline velocities
• Operational aspects such as pump speed control, valve positions and valve operating times

 


Pump head and flow rate

The pump head will have a static and dynamic component, and these factors will determine the system resistance curve. A typical system resistance curve is shown below.

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Valves

The following can be provided for valve installations:

•    Analysis of the use of control or isolating valves,
•    Simulation of flow control,
•    Estimation of losses through valves
•    Estimation of valve cavitation

Types of valves

Experience has been gained over many years with the following types of valves:

Common water valves:
Gate valves,
Butterfly valves
Butterfly valves with two-speed closure

Control Valves
Control valves such as Fisher V ball valves,
CCI stacked disc valves
Copes Vulcan control valves
Butterfly valves used as control valves

Non-return valves as follows:
Swing-check valves
Faster closing valves such as Valmatic surge buster valves
Nozzle-check fast closing valves for use with high system deceleration