Analysis of the causes of failures and damages in chemical magnetic pumps

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Analysis of the causes of failure and damage in chemical magnetic pumps. A chemical magnetic pump consists of three components: the pump itself, the magnetic drive unit, and the electric motor. The magnetic drive of the key component consists of an outer magnetic rotor, an inner magnetic rotor, and a non-magnetic isolation sleeve. When the electric motor drives the external magnetic rotor to rotate, the magnetic field can penetrate the air gap and non-magnetic materials, causing the internal magnetic rotor connected to the impeller to rotate synchronously. This enables contactless transmission of power, thereby converting dynamic sealing into static sealing. Since the pump shaft and internal magnetic rotor are completely enclosed by the pump body and isolation sleeve, the problems of leakage are resolved, eliminating the safety risks associated with the leakage of flammable, explosive, toxic, and harmful substances in the chemical industry through the pump seals. However, all machinery is subject to wear and failure. Below are several common causes of failures in chemical magnetic pumps, as analyzed for users: 1. Damage to the isolation sleeve: The magnetic coupling in a chemical magnetic pump is cooled by the medium being pumped. If there are hard particles in this medium, it can easily cause scratches or punctures in the isolation sleeve; improper maintenance methods can also lead to damage to this sleeve. 2. No medium or low flow rate of the conveying medium: This causes dry friction between the bearings, leading to their destruction. Chemical magnetic pumps use the medium being transported to provide lubrication and cooling for the sliding bearings; in the absence of an inlet valve or an outlet valve, the sliding bearings get damaged due to the lack of lubrication and cooling from the transported medium. 3. Problems caused by large fluctuations in the pump’s operating conditions: The axial force in chemical magnetic pumps is automatically balanced through hydraulic equilibrium. In actual operation, if the operating parameters fluctuate greatly, it is easy to disrupt the hydraulic balance of the magnetic pump, causing the sliding bearings to experience large radial and axial forces that result in bearing damage. 4. Problems caused by cavitation in pumps: The main reasons for cavitation in pumps include high resistance in the pump inlet pipe, a high gas content in the fluid being transported, insufficient priming of the pump, and insufficient energy head at the pump inlet. Cavitation poses the greatest threat to pumps; when it occurs, the pump vibrates violently and the hydraulic balance is severely disrupted, which can lead to damage to the pump’s bearings, rotor, or impeller. This is a common cause of failures in magnetic pump systems.