Changsha Zoomlian Pump Co., Ltd. 长沙中联泵业股份有限公司

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    In-depth Analysis of Causes for Excessive Heating in Centrifugal Pump Bearings, Troubleshooting Methods, and Preventive Measures

    Publication Date:

    2025-11-22

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    Over the years of engineering experience, Zhonglian Pump Industry has identified abnormal temperature rise in centrifugal pump bearings as a typical failure that requires our utmost attention and precise troubleshooting. This issue not only affects equipment efficiency but also plays a critical role in ensuring the continuous and safe operation of pump stations. Essentially, bearing overheating stems from an imbalance between frictional forces and heat generation. Moving forward, the centrifugal pump manufacturer… Changsha Zoomlion Pump Industry Based on the understanding of fluid dynamics and mechanical seals, this article provides an in-depth analysis of the causes of excessive bearing heat in centrifugal pumps, along with troubleshooting methods and preventive measures.

     

    Centrifugal pump

     

     

    1. The core sources of mechanical friction heat often revolve around lubrication and installation accuracy.

     

    The "health" status of lubricants and quantitative management: Lubricating oil is the "blood" of bearings. Contamination, aging, or even simple oil-level deviations—whether excessive, leading to heat generation from agitation, or insufficient, causing dry friction—can all directly compromise the oil film, dramatically increasing frictional heat. Meanwhile, don’t overlook the importance of smooth drainage in the return oil tank; if the tank becomes clogged, it may result in falsely high oil levels or prevent the lubricant from circulating effectively.

     

    Bearing

     

    Suggestion: Strictly adhere to the oil testing cycle and ensure the use of the specified grade. Oil levels must be precisely maintained at the centerline indicated by the dipstick or oil mark. Regularly inspect and clean the return oil tank.

     

    Strict alignment precision requirements: Improper alignment between the driver and the pump coupling is the primary culprit behind mechanical friction. Even minor angular or parallel misalignments can translate into substantial radial or axial loads during high-speed operation, leading to abnormal wear and overheating of the bearing raceways.

    Suggestion: Use a laser alignment tool for high-precision calibration to achieve minimal cold-state misalignment. For high-temperature, high-pressure pumps, obtain accurate thermal expansion data to allow for proper hot-state alignment corrections.

     

    II. The pump's own operational status and environmental factors are indispensable indirect drivers.

     

    The "penalty" for operating far from the design conditions: When the pump's actual flow rate and head significantly deviate from the optimal efficiency point, BEP ) can trigger hydraulic instability within the pump body. This typically manifests as intensified internal backflow and vortex formation, generating strong radial forces. Such hydraulic imbalance does not directly cause overheating; instead, it exerts lateral thrust on the shaft, ultimately transferring this excessive load—far beyond the design capacity—to the bearings, indirectly leading to temperature rise.

     

    The "moisture-proof" project for the bearing chamber: Water molecules entering the bearing chamber—whether through seal leaks or condensation from ambient humidity—can lead to lubricant emulsification, compromising the oil film's strength and ultimately causing rusting and a sharp rise in frictional heat.

    Suggestion: Inspect and improve the bearing housing seals (such as labyrinth seals or oil seals) to ensure isolation from the surrounding environment.

     

    The "test" of medium-induced heat transfer and ambient cooling: When transporting high-temperature media, heat is conducted along the pump shaft toward the bearing housing. If this accumulated heat cannot be dissipated promptly—and if the pump design lacks effective cooling or thermal isolation measures (such as cooling water jackets or heat sinks)—the bearing temperature will exceed safe limits. Additionally, excessively high ambient temperatures in the pump room, combined with significant dust buildup or oil contamination on the surface of the bearing housing, can severely reduce cooling efficiency.

    Suggestion: Ensure the cooling system (if equipped) is functioning properly, and keep the bearing housing surfaces clean to improve ventilation in the pump room.

     

    3. The quality of the bearing itself is ultimately responsible for all issues.

     

    The reliability and lifespan of the bearing body: Whether it's an inherent quality defect in the bearing or severe wear after prolonged operation under high loads, both ultimately lead to temperature rise. Wear results in changes in clearance and a loss of geometric precision, directly manifesting as increased heat generation.

    Suggestion: Perform preventive replacements according to the manufacturer’s recommended schedule, and use high-quality bearings from authorized channels.

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