Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

Search is the most efficient way to navigate the Engineering ToolBox!

Pumps - Parallel vs. Serial Arrangement

Sponsored Links

Pumps can be arranged and connected in serial or parallel to provide additional head or flow rate capacity.

Pumps in Serial - Head Added

When two (or more) pumps are arranged in serial their resulting pump performance curve is obtained by adding their heads at the same flow rate as indicated in the figure below.

Centrifugal pumps in series are used to overcome larger system head loss than one pump can handle alone.

  • for two identical pumps in series the head will be twice the head of a single pump at the same flow rate - as indicated with point 2. 

With a constant flowrate the combined head moves from 1 to 2 - BUT in practice the combined head and flow rate moves along the system curve to point 3.

  • point 3 is where the system operates with both pumps running 
  • point 1 is where the system operates with one pump running

Note that for two pumps with equal performance curves running in series

  • the head for each pump equals half the head at point 3
  • the flow for each pump equals the flow at point 3

Operation of single stage pumps in series are seldom encountered - more often multistage centrifugal pumps are used. 

.

Pumps in Parallel - Flow Rate Added

When two or more pumps are arranged in parallel their resulting performance curve is obtained by adding the pumps flow rates at the same head as indicated in the figure below.

Centrifugal pumps in parallel are used to overcome larger volume flows than one pump can handle alone.

  • for two identical pumps in parallel and the head kept constant - the flow rate doubles compared to a single pump as indicated with point 2

Note! In practice the combined head and volume flow moves along the system curve as indicated from 1 to 3.

  • point 3 is where the system operates with both pumps running 
  • point 1 is where the system operates with one pump running

In practice, if one of the pumps in parallel or series stops, the operation point moves along the system resistance curve from point 3 to point 1 - the head and flow rate are decreased.

Note that for two pumps with equal performance curves running in parallel

  • the head for each pump equals the head at point 3
  • the flow for each pump equals half the flow at point 3

Note - for parallel operation

  • zero flow or “shut valve” heads must match for the pumps
  • unstable pump curves must be avoided
  • steeper pump curves are preferred
Sponsored Links

Related Topics

Pumps

Design of pumping systems and pipelines. With centrifugal pumps, displacement pumps, cavitation, fluid viscosity, head and pressure, power consumption and more.

Related Documents

Alternating Pumps

Securing a system and achieve equal wear by alternating pumps in parallel.

Centrifugal Pumps

An introduction to Centrifugal Pumps.

Positive Displacement Pumps

Introduction tutorial to positive displacement pumps basic operating principles.

Pressure Loss in Pipes connected in Series or Parallel

Calculate pressure loss in pipes connected in series or parallel.

Pumping Water - Energy Cost Calculator

Calculate the energy cost of pumping water.

Pumping Water - Required Horsepower

Horsepower required to pump water.

Static Pressure vs. Head

Static pressure vs. pressure head in fluids.

System Curve and Pump Performance Curve

Utilize the system curve and the pump performance curve to select the proper pump for a particular application.

Sponsored Links

Search Engineering ToolBox

Search is the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics on the AMP pages. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.