Technical Analysis: Root Causes and Evolution Patterns of Bearing Housing Overheating in Horizontal Centrifugal Pumps

In industrial fluid transportation systems, the operational stability of a Horizontal Centrifugal Pump is directly related to the continuity of the production line. Among various maintenance fault statistics, Bearing Housing overheating is a high-frequency failure second only to seal failure. An abnormal rise in the temperature of the bearing housing usually serves as a thermometer for early failure signals of the pump unit. If not handled properly, it will quickly evolve into bearing seizure, shaft bending, or even total equipment loss.

Micro-friction Mechanism of Bearing Housing Overheating

Churning Effect of Lubricants

A common cognitive misunderstanding is that the more lubricating oil or grease, the better. In fact, when the oil level in the Bearing Housing exceeds the standard height (usually the centerline of the lowest rolling element), the high-speed rotation of the bearing creates a violent stirring action.

Viscous Drag: Excessive lubricating oil generates huge internal friction resistance, converting kinetic energy into thermal energy, leading to a temperature rise. Aeration: High-speed stirring causes the lubricating oil to foam, which reduces the strength of the lubrication film and causes poor lubrication.

Disappearance of Internal Clearance

When the bearing is working, the thermal expansion of the inner ring is usually higher than that of the outer ring. If the initial Internal Clearance is improperly selected or heat dissipation is blocked, the expansion of the inner ring will squeeze the rolling elements.

Thermal Runaway: Friction heat causes expansion, and expansion further increases friction, forming a vicious cycle that eventually leads to bearing burnout.

In-depth Analysis of Core Inducing Factors

Additional Load Caused by Misalignment

Parallelism or Angular Misalignment between the drive end and the pump end shafts forces an axial force or radial load on the bearing that is not in the design state. This eccentric operation leads to excessive local pressure on the bearing raceway, a sharp increase in the local friction coefficient, and rapid heat diffusion to the Bearing Housing.

Abrasive Wear Caused by Contamination

When oil seals fail or external dust enters the sealing chamber, tiny solid particles enter the bearing raceway.

Three-Body Abrasion: Particles act as sandpaper between the rolling element and the raceway, destroying the Lubrication Film. The resulting mechanical heat causes the bearing housing shell to become extremely hot.

Operation Deviating from BEP (Best Efficiency Point)

When a horizontal pump runs in the low flow area for a long time, serious Recirculation and radial forces are generated internally. This unbalanced force is transmitted to the bearing through the pump shaft, causing the bearing to bear a fatigue load far exceeding the design specifications, significantly increasing heat production.

Technical Countermeasures and Evolution of Lubrication Schemes

Choice Between Oil Mist Lubrication and Oil Bath

In high-temperature and high-speed working conditions, traditional Oil Bath lubrication is gradually replaced by Oil Mist due to limited heat dissipation capacity. Oil mist lubrication brings micron-sized oil droplets into the bearing through compressed air, providing fresh oil while using air flow to take away a large amount of heat, significantly reducing the operating temperature of the Bearing Housing.

Integrity Check of Cooling Systems

For Bearing Housing equipped with water-cooling jackets or internal cooling coils, Scaling is the main cause of the decline in heat exchange efficiency. Even if the cooling water flow rate reaches the standard, if the internal wall scaling is serious, the thermal resistance will prevent the heat generated by the bearing from being effectively discharged.