Magnetic pumps are widely used in chemical, pharmaceutical, electronic, electroplating and other fields due to their good sealing, simple structure and no leakage. However, during the use of magnetic pumps, heating of the pump head is a common problem. Understanding the cause of heating can effectively prevent equipment damage and safety accidents.

Four main causes of fever

1.Dry running (no medium operation): When the pump is started or operated without liquid or the liquid level is too low, the bearing loses lubrication and cooling, the eddy current heat cannot be discharged, and the temperature rises suddenly, causing the bearing to burn or the isolation sleeve to rupture.

2.Magnetic eddy current loss: an inherent cost of the structure. The active rotor rotates to generate an alternating magnetic field. When passing through the isolation sleeve, a current (eddy current) is induced in the sleeve, causing the isolation sleeve to heat up. The higher the speed, the stronger the magnetic force, and the thicker the isolation sleeve, the more obvious the heat. Even if the medium is sufficient and the working conditions are normal, the pump head (especially the isolation sleeve area) will have a temperature rise. This is an inherent characteristic of the design.

3.Conveying medium problem：

High viscosity liquid: poor fluidity, large internal friction resistance (viscous shear heating), and more difficult to remove heat from the pump.

Contains particulate impurities: It increases the friction and wear of bearings, sleeves, impellers and other flow-through parts, and generates additional heat.

High temperature medium: The inlet temperature is high, and when flowing through the pump body, it further absorbs the heat generated by friction and eddy current, and the outlet temperature is even higher.

Poor lubricity: Certain light hydrocarbons and ultrapure water, for example, cannot effectively lubricate bearings or remove heat.

4.Overload and cooling failure

Overload slip: When overloaded, the magnetic rotor slips, and the eddy current loss increases sharply, leading to high temperature.

Cooling interruption: Auxiliary cooling/flushing pipeline is blocked and heat cannot be discharged (common in high temperature and crystallization-prone media).

Practical solutions

1.Prevent idling: The machine must be filled with liquid before starting, and a liquid level sensor interlock protection should be installed.

2.Optimize operation: avoid closing the outlet valve for a long time and clean the cooling pipeline regularly.

3.Accurate selection: choose large clearance bearings for high viscosity media and use forced cooling system for high temperature media.

4.Daily maintenance: monitor the temperature of the bearing parts (stop the machine if it is higher than 150℃) and regularly check the clearance and wear of the magnetic rotor.

Safety Tips

1.High temperature burns: The temperature of the pump head during operation or just stopped may be extremely high, so do not touch it directly.

2.Media risk: Overheating of the pump head may lead to a sharp increase in the risk of leakage of hazardous media (toxic, flammable and explosive).

3.Electrical safety: Overheating may damage seals or accessories, causing secondary risks such as short circuits.

The heating of the pump head of the magnetic pump is the result of multiple factors. From strictly prohibiting idling, paying attention to the characteristics of magnetic eddy currents, to matching the medium and system design, every link needs to be treated rigorously. The temperature rise (30~50℃) caused by magnetic eddy currents is a normal phenomenon, but abnormal heating needs to be checked immediately. Understanding these principles, through scientific management and preventive maintenance, can significantly improve the reliability and service life of the equipment.