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.
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
• 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