Difference between different types impeller (Open, Semi-Open , Close)

Open Impeller:

Those impellers vanes which are open on both sides and have no wall surrounding the vanes.

Application: Used as a pump where workload is low and fluid contains abrasive particles.Note: these impellers less prone to clog or particle   blockage 

Advantage :

1. Easy to clean
2. Easy to repair
3. Faster
4. Can handle suspended Solids

Disadvantage:

1. Only good for smaller load work
2. Low efficiency
3. Required high NPSH(net positive suction head) to reduce cavitation effect

Semi-Open Impeller:

Those impellers vanes which are open on both sides and have wall surrounding the vanes.

Application: Use for the medium workload. It can also handle mud or abrasive particle in the fluid. This impeller efficiency is in between close and open impeller

Advantage :

1. Used with fluid have dirt  abrasive particle
2. Higher-strength as compare to open impeller
3. Better efficiency as compare to open impeller

Disadvantage:

1. Clearance between the vanes and casing must be small else large slippage and recirculation will occur
2. Low efficiency as compare to close impeller

Close Impeller:

These impeller vanes have have a wall on both sides (front and back) .It increase its strength

Application: These impellers are used for heavy workload and Commonly used with clean liquid (water treatment plant or other  industry dealing with liquid )

Advantage:

1. High efficiency as compare to open and semi open impeller
2. Provide more flow at low NPSH(Net positive suction head)
3. Give constant efficiency during work

Disadvantage:

1.  Complex Design
2. Expensive (high maintenance  and making  cost)
3. More Prone to clogging
4. Not suitable for abrasive fluids