Under prolonged exposure to harsh, high-temperature, and dusty operating conditions, engine explosion-proof cooling fan blade failures often fall into three main categories: material degradation, structural damage, and explosion-proof function failure. These can be broken down into six typical failure types, each directly associated with safety hazards:
1. Wear and Delamination of the Explosion-Proof Coating
High temperatures accelerate the aging and embrittlement of the coating. High-dust particles (such as coal dust and metal debris) driven by high-velocity airflow continuously scour the blade surface, causing scratches and flaking of the anti-static and high-temperature resistant coatings.
Hazards: Coating delamination reduces the blade's electrical conductivity, allowing static electricity to accumulate and spark. Furthermore, the exposed metal substrate is more susceptible to friction with dust at high temperatures, generating heat and exceeding the explosion-proof safety threshold.
2. Blade Wear and Deformation
Continuous impact from dust particles can cause wear on the blade edges and windward surface, resulting in gaps and thinning. High temperatures weaken the strength of blade materials (such as aluminum alloys and composite materials). Long-term high-speed rotation can easily lead to plastic deformation, resulting in blade bending and tip tilt. Hazards: Wear can lead to reduced airflow and insufficient engine heat dissipation; deformation can cause the fan's dynamic balance to become unbalanced, resulting in violent vibration, further exacerbating bearing wear and even causing blade breakage.
3. Bearing Seizure and Wear
High temperatures can destabilize bearing grease, causing it to dissipate or deteriorate, leading to dry friction in the bearings. Dust can easily enter the bearing clearances, causing abrasive wear and scratching the inner and outer races and ball bearings.
Hazards: When bearings seize, fan speed drops sharply, dramatically reducing heat dissipation efficiency. Simultaneously, the high temperatures generated by friction (which can reach over 800°C) can directly burn the blades and even cause metal-to-metal sparks in the bearings, posing an explosion risk.
4. Failure of the Static Discharge Mechanism
High temperatures can oxidize the conductive bolts and copper washers connecting the blades to the hub, forming an oxide layer that blocks the static conduction path. Dust accumulation at the grounding interface can also increase ground resistance (exceeding the safety standard of 4Ω).
Hazards: Static electricity cannot be properly discharged, increasing the static voltage on the blade surface, which can break through the air and form static sparks. This can become a direct ignition source, especially in environments with high concentrations of flammable gases. 5. Failure of the Flameproof Enclosure Seal

High temperatures can cause the sealant on the enclosure joints to age and shrink, creating gaps. Dust particles can easily embed themselves in the seals, and long-term accumulation can wear away the flameproof joints, causing the gap to exceed the safety standard of 0.1mm.

Hazard: When the seal fails, combustible gases and dust from the outside can enter the fan. If a localized flame occurs due to a fault, it can spread directly through the gaps to the outside, causing an explosion.

6. Material Cracking Due to High-Temperature Aging

Extended exposure to temperatures exceeding 150°C (such as near the engine exhaust pipe) can cause composite materials (such as carbon fiber) to delaminate from the resin matrix, and metal materials (such as mild steel) to suffer intergranular corrosion, ultimately leading to microcracks at the blade roots and stress concentration points.

Hazard: Cracks can continue to grow. Under the centrifugal force of high-speed rotation, they can cause the blades to break suddenly, with flying fragments causing sparks. The fan will also lose its heat dissipation function, putting the engine at risk of overheating and shutdown.

Would you like me to compile a troubleshooting and maintenance checklist for you? The list will clearly define the inspection cycle, judgment criteria and handling methods for each fault, making it easier to quickly identify hidden dangers during daily operation and maintenance.