Pipe equivalent length in pneumatic transport

Pipe equivalent length for calculation of pressure drop in conveying pipes

Section summary
1. Definition
2. Calculation of the pipe equivalent length - shortcut
3. Calculation of the pipe equivalent length - details

Pneumatic Transport
Types of pneumatic transport
Conveying phases
Dilute Phase transport
Dense Phase transport
Air mover
Roots Blower
After Cooler
Airlock Rotary Valve
Product inlet / Injector
Pick-up velocity
Conveying speed / velocity
Air volumetric and mass flowrate
Pipe Equivalent Length
Solids velocity in pipe
Solids Breakage
Pressure drop
Pipe Diameter or Bore
Design methods
Pipe Blockage
Powder Build-up
Selecting dilute or dense phase
Horizontal Conveying
Vertical Conveying

1. Definition

Several methods to calculate the pressure drop expected in a pneumatic conveying pipe and design it is using the notion of equivalent pipe length. This notion is actually quite convenient to simplify the calculation of pressure drop. It converts the singularities of the pipe layout (vertical sections, bends, valves...etc...) into an equivalent length of straight horizontal pipe which is representing the same pressure drop as the singularity. This page is explaining different ways to calculate the pipe equivalent length.

2. Calculation of pipe equivalent length - simplified method

A very simple way to calculate the equivalent length is to count on the pipe layout the length of horizontal pipe, vertical pipes and the number of bends.

The pipe equivalent length can be estimated in this shortcut method by Le = Lh+2*Lv+5*NB

With :

- Le = equivalent length of the pipe (m)
- Lh = length of horizontal pipe in the whole pipe layout (m)
- Lv = length of vertical pipe in the whole pipe layout (m)
- NB = number of bends

Do not use this method for detail design. But it can be useful for a pre-project or quite troubleshooting on a production line.

3. Calculation of pipe equivalent length - detailed method

Note : this page is under development and review, it will be updated soon.

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