6 Types of Impellers: Definition and Uses
In many cases, industrial applications, like power generation, pharmaceuticals, and oil refining, are reliant on centrifugal pumps. The most important component of a centrifugal pump is the impeller.
This guide is the best source to know what an impeller is, the different types of impellers, and their uses.
What is an Impeller?
An impeller is a rotor that drives to increase the flow and pressure of a liquid. It is made using steel or iron and is in the form of a rotating disc composed of vanes.
The rotating disc of the impeller has curved blades. These blades help create a vacuum and pull the liquid from the center, diverting it in the outward direction.
6 Types of Impellers and Their Uses
The six types of impellers and their uses are given below.
1. Open Impeller
The open impeller consists of vanes that are attached to the central hub and do not have a cover or shroud. It is opted for the purpose of pumping liquids that have low viscosity and no suspended solids. It is very easy to maintain and clean. These impellers are easy to manufacture but not very efficient.
Open impellers are used in the food industry, chemical processing, and water treatment.
2. Semi-Open Impeller
The semi-open impeller is composed of vanes on one side of the central part and is open on the other side. These impellers are suitable for pumping liquids that have suspended solids. These impellers are hard to maintain and manufacture but offer high efficiency.
The semi-open impellers are used in the chemical, mining, and food processing industry.
3. Closed Impeller
A closed impeller has vanes that have a cover or a shroud in their surroundings. The presence of shrouds and covers adds efficiency to its operation, and it can pump liquids having suspended solids. The process of cleaning and maintaining the closed impeller is quite challenging, however, it is highly efficient.
Closed impellers are opted in industries like mining, paper, and wastewater treatment.
4. Vortex Impeller
A vortex impeller is composed of a recessed chamber that handles the fluids consisting of gas, this chamber creates a vortex. These impellers are suitable for pumping liquids that have gas and air. It may handle fluids with high gas content, but they are not very efficient
The application of vortex impellers is observed in the oil and gas industry.
5. Screw Impeller
The screw impeller is suitable for pumping liquids that are thick and consist of large solid particles. These impellers consist of a screw-like channel design, which has an opening that allows solids to pass through. It is highly efficient and clog-resistant.
Screw impellers are used in marine applications, the oil and gas industry for pumping thick liquids which may have solid particles, and also in the food industry.
6. Chopper or Cutter Impeller
Cutter impellers are also known as chopper impellers, and they can handle the pumping of solids. They have vanes with sharp edges and a scissor-like structure, which helps in shredding and grinding solids before allowing them to enter the pump. These impellers help prevent clogging.
The cutter and chopper impellers are used in waste and sewage management applications.
How to Choose the Right Impeller Type?
It is very important to choose the right type of impeller for the right application, one that allows smooth pumping of the liquid.
Some of the considerations which are important when choosing the type of impellers are the following:
- Low viscosity liquids which do not contain suspended solids are suitable to go with open impellers.
- Fluids that have suspended solids may easily pass through closed impellers.
- The selection of the type of impeller must be made based on the efficiency, cost, maintenance, and the required rate of flow.
- Semi-open impellers are such types of impellers that offer a combination of open and closed impellers.
- The fluids that consist of high solid content work well with recessed impellers.
- Liquids that have a high gas content opt vortex impellers.
Conclusion
Choosing the right type of impeller that has the right manufacturing and properties is important. If you are looking to have adequate types of impellers for your applications, you can contact us.
We at DEK manufacture custom impellers of every type, which cater to various applications based on your specifications.
FAQs
What is the function of the impeller?
An impeller carries out the function of accelerating fluid away from the center of rotation outwards. Then transfers the energy from the motor, which is driving the pump, to the liquid that is pumped.
Which type of impeller is most common?
Closed impeller is a very common type of impeller that is used in pumps where high-viscosity liquids are pumped.
What is the difference between an impeller and a propeller?
The impeller pulls the liquid in the outward direction, whereas the propeller pushes the fluid.
