The magnetically coupled centrifugal pump is an innovative technology that is characterized by its hermetically sealed design and high operational reliability. This type of pump is primarily used in applications where no leaks can be tolerated, such as when pumping aggressive, toxic or environmentally hazardous liquids. The use of a magnetic drive eliminates the need for a mechanical shaft seal, which reduces maintenance costs and increases the reliability of the pump.

Functionality of a magnetically coupled centrifugal pump

The magnetically coupled centrifugal pump works on the principle of rotary motion transmission by magnets. The main components are

1. Drive magnet: The drive magnet is directly connected to the motor and transmits the rotary movement.

2. Inner magnet: The inner magnet is connected to the pump impeller and is located inside the hermetically sealed housing.

3. Can: The can separates the drive magnet from the inner magnet and ensures a complete seal. It is often made of highly resistant materials such as stainless steel or plastic.

4. Impeller: The impeller conveys the medium by centrifugal forces.

The rotary motion of the motor is transmitted to the inner magnet by the drive magnet without any mechanical connection. As a result, the medium is hermetically sealed and there are no leaks.

Advantages of the magnetically coupled centrifugal pump

1. zero leakage: Since no mechanical shaft seal is required, magnetically coupled pumps are absolutely leak-proof. This makes them ideal for handling toxic, volatile or environmentally hazardous media.

2. high chemical resistance: The materials used for the can and the internal components are highly resistant to aggressive chemicals such as acids, alkalis and organic solvents.

3. low maintenance requirements: Since no mechanical seals can wear out, maintenance requirements are significantly reduced. This leads to lower operating costs.

4. high operational reliability: Due to the elimination of potential leakage sources and the robust design, magnetically coupled centrifugal pumps offer a high level of reliability.

5. versatility: These pumps are suitable for a wide range of media and applications, from water treatment to the chemical process industry.

Materials and construction

The choice of material is decisive for the chemical resistance and durability of the pump:

• Can:

  • Stainless steel: Outstanding mechanical strength and chemical resistance.

  • Plastic (e.g. PVDF, PTFE): Resistant to highly aggressive media and corrosion.

• Impeller and housing:

  • Cast iron: For neutral or slightly abrasive media.

  • High-performance plastics: For aggressive chemical applications.

• Magnetic materials:

  • Rare earths such as neodymium or samarium-cobalt ensure high magnetic force and temperature resistance.

Applications in water and wastewater technology

1. dosing and transporting chemicals: Magnetically coupled centrifugal pumps are often used for pumping aggressive chemicals such as acids and alkalis as well as highly corrosive substances. Their leakage-free operation is particularly important here in order to avoid environmental contamination.

2. water treatment: These pumps are used in reverse osmosisand ion exchange systems to safely pump chemical cleaning and regeneration solutions.

3. wastewater treatment: Magnetically coupled pumps are ideal for handling toxic or corrosive wastewater, as they ensure safe and loss-free operation.

Challenges and solutions

1. temperature management: Magnetically coupled pumps can be heated by the magnetic drive. Sufficient cooling of the can is crucial, especially with highly viscous or poorly heat-conducting media.

2. dry running: As these pumps rely on the medium as a lubricant, they can be damaged if they run dry. Dry-running protection systems prevent such operating conditions.

3. magnet decoupling: Excessive loads, for example due to high viscosities or blocked lines, can cause the magnets to decouple. An exact design of the pump for the operating case is crucial here.