What Is An Impeller?
Impeller is a rotating part of the pump, so the pump uses the rotation of the impeller to drive fluid movement. In order to make impeller more durbale, manufacturers generally use metal and rubber to make it, which gives it wear-resistant and corrosion-resistant properties.
How Does Impeller Work?
During centrifugal pump operation, the impeller is responsible for converting the mechanical energy of the motor into the kinetic and pressure energy of the fluid.
Because the impeller rotation generates centrifugal force, under the action of centrifugal force, the impeller draws fluid into the pump. During the rotation, the impeller throws the fluid around, increasing the flow rate and converting the fluid’s kinetic energy into pressure energy. Finally, the pump ejects fluid from the outlet.
Types Of Impeller
1. Open Impeller
Open Impeller Features
The open impeller design has the blades directly connected to the impeller center, so blades come into direct contact with the fluid as there is no front or back cover.
Because of the open space of the open impeller, it is suitable for conveying large particles and medium to high viscosity fluids.
| Pros, cons and uses | |
| Advantages | ●Clog-resistant ●Simple structure ●Low cost |
| Disadvantages | ●Low impeller strength ●Low conveying efficiency |
| Application | ●Mine slurry ●Sewage ●Mud ●Conveying fluids containing suspended solids |
2. Semi-open Impeller
Semi-open Impeller Features
The semi-open impeller design has a cover on one side, however the blades come into direct contact with the fluid medium on the other side.
The efficiency of semi-open impeller is between open impeller and closed impeller, it is generally suitable for conveying fluids with a small amount of solid particles.
| Pros, cons and uses | |
| Advantages | ●Clog-resistant ●High efficiency ●High robustness |
| Disadvantages | ●Fluid recirculation may occur in the gap between the impeller and the pump casing |
| Application | ●Petrochemical ●Sewage treatment ●Mining ●Conveying fluids containing suspended solids ●Conveying viscous fluids |
3. Closed Impeller
Closed Impeller Features
The closed impeller design has covers on both sides. Because there is a closed flow channel inside the impeller, the closed impeller has a high conveying efficiency.
| Pros, cons and uses | |
| Advantages | ●High conveying efficiency ●Sturdy structure ●Conveys high-pressure fluids |
| Disadvantages | ●High-cost ●Harder to clean |
| Application | ●Petrochemical ●Mining ●Dredging ●Shield tunnel |
4. Recessed Impeller
Recessed Impeller Features
A part of the blades of the recessed impeller is telescoped to the inside of the pump body, and through the rotation of the impeller, the fluid in the pump body generates a vortex effect, thus driving the fluid to move.
Because the blade of the recessed impeller are not in direct contact with the conveyed medium, the recessed impeller is more durable.
| Pros, cons and uses | |
| Advantages | ●Clog-resistant ●Wear-resistant ●Long service life ●Conveys fluids with large particles ●Handles long fibers fluid |
| Disadvantages | ●Inefficient ●Cannot transport fluids at high pressure and high head |
| Application | ●Sewage plants ●Mining ●Paper ●Chemical |
5. Vortex Impeller
Vortex Impeller Features
As the name suggests, a vortex impeller is an impeller that moves fluid through the vortex effect, since it does not come into contact with the fluid, reducing clogging and corrosion.
| Pros, cons and uses | |
| Advantages | ●Clog-resistant ●Wear-resistant ●Long service life |
| Disadvantages | ●Inefficient, impeller is not in contact with the fluid, but moves the fluid by vortexing |
| Application | ●Mining slurry ●Sewage treatment ●Coal mining ●Paper making |
6. Cutter Impeller
Cutter Impeller Features
The cutting impeller is installed with a cutter, which cuts long fibers or large particles of suspended matter when the fluid is inhaled so that the fluid can be inhaled smoothly.
| Pros, cons and uses | |
| Advantages | ●Clog-resistant ●Less frequent maintenance ●Conveying fluids with large suspended particles ●Conveying fluids with long fibers |
| Disadvantages | ●Inefficient, impeller is not in contact with the fluid, but moves the fluid by vortexing |
| Application | ●High power consumption ●Faster impeller wear |
7. Screw Impeller
Screw Impeller Features
Because the screw impeller is similar to a propeller thruster, it can axially and steadily convey fluids
| Pros, cons and uses | |
| Advantages | ●Clog-resistant ●Conveys highly viscous fluids |
| Disadvantages | ●High cost ●Low head ●Low pressure |
| Application | ●Petrochemical ●Food ●Pharmaceutical ●Mining |
1 Min Video: 3 Main Impeller Types Explained!
How To Choose The Right Impeller?
Different impeller types have different functions, selecting an impeller requires professional judgment based on the working conditions of the application as well as other indicators. The following are 5 factors that are important when selecting impeller types.
1. Flow rate
Because the flow rate affects the diameter and design shape of the impeller, when high flow rate conveying is required, the impeller diameter can be increased to increase the conveying flow rate.
2. Head
When pumping a fluid that requires a larger head, a more closed impeller can be selected and the angle of the vanes can be adjusted to increase the pressure.
3. Viscosity
According to the viscosity of the fluid and other factors can be decided on the number of blades of the impeller, when it is necessary to pump a larger viscosity of the fluid, the number of blades need to be reduced in order to reduce the conveying resistance.
4. Solids content
Solids content is an important indicator of impeller selection, and there is a risk of easy clogging if the selection is wrong.
5. Materials
The impeller is selected according to the type of fluid to be conveyed. In order to make the impeller more durable, the impeller is usually made of wear-resistant metal and corrosion-resistant rubber.
FAQ About Impeller
What Is The Advantage Of An Impeller Pump?
Impeller pumps have many advantages, such as simple structure, easy maintenance, high efficiency, long service life and a wide range of applications.
Impeller vs. Propeller
| Components | Design | Function |
| Impeller | Impellers are fan-like structures that usually operate in a closed structure. | The main function of the impeller is to generate centrifugal force to move the fluid. |
| propeller | Propellers have helically structured blades up the shaft, and propellers generally operate exposed to the fluid. | The main function of a propeller is to act as a propelling tool, creating thrust in the water to move an object forward. |
Which Type Of Impeller Is Most Efficient?
The characteristics of each impeller are different, and the conveying efficiency should be judged according to the physical properties of the medium and the user’s needs, such as: solid content, viscosity, head and pressure to be pumped.
If the medium to be conveyed is clear water or medium with less suspended matter, the closed impeller is the best choice and its conveying efficiency is excellent.
