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Why do mechanical seals for industrial pumps leak frequently?How to accurately pinpoint the core culprit of failure?

Luojiang industrial zone,hemudu town,yuyao city,ningbo,china
+86-0574-62962895
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market@bonvepumps.com

Why do mechanical seals for industrial pumps leak frequently?How to accurately pinpoint the core culprit of failure?

Time of issue:2026-04-08

(Summary description)Mechanical seal leakage is a high-frequency failure in the operation of fluid conveying equipment. From four dimensions – mechanical damage, thermal failure, face wear characteristics, and leakage performance – this article breaks down the core triggers corresponding to different failures, and simultaneously provides actionable rectification and prevention solutions to help equipment operation and maintenance quickly troubleshoot and resolve leakage issues.

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Why do mechanical seals for industrial pumps leak frequently?How to accurately pinpoint the core culprit of failure?

(Summary description)Mechanical seal leakage is a high-frequency failure in the operation of fluid conveying equipment. From four dimensions – mechanical damage, thermal failure, face wear characteristics, and leakage performance – this article breaks down the core triggers corresponding to different failures, and simultaneously provides actionable rectification and prevention solutions to help equipment operation and maintenance quickly troubleshoot and resolve leakage issues.

Categories:Development path
Author:Bonve Pump Industry Marketing Department
Origin:Bonve Pump Industry Marketing Department
Time of issue:2026-04-08 08:47
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Information

Find the Culprit of Mechanical Seal Leakage

In the fluid conveying link of industrial production, the mechanical seal is the core component that prevents medium leakage and ensures stable equipment operation. Especially for rotary lobe pumps that convey high-viscosity, high-value media, sealing performance directly determines the safety and continuity of production. In daily maintenance, seal leakage occurs frequently with complex causes; only by accurately locating the root cause of the fault can the problem be fundamentally solved.

-Bonve Pump Cam-Type Twin-Rotor Pump-

Directly locate the intuitive failure root cause from mechanical damage. This is the most common trigger of seal leakage. Typical issues include brittle cracking of the rotating ring, distortion and deformation of the sealing face, scratches and scoring on the end face, failure of transmission components, and loss of spring elasticity. For example, for a cracked rotating ring: if the fracture surface shows uneven discoloration accompanied by wear debris, it is mostly caused by excessive compression during operation, high pump pressure, or dry running; if the fracture surface has no abnormality, it is mostly caused by improper disassembly and assembly. Uneven tightening of gland bolts and imbalanced thermal stress can easily cause distortion of the sealing face, leading to continuous leakage.

Identify hidden failure causes from thermal damage. The heat generated by high-speed friction on the sealing face is an important driver of seal failure. Thermal cracking of the sealing ring, vaporization leakage on the end face, and aging and embrittlement of auxiliary sealing elements are all directly related to thermal damage. When the lubrication and cooling of the sealing face are insufficient, the liquid film vaporizes, or the PV value exceeds the limit, radial thermal cracks appear on the sealing face. In this case, it is necessary to ensure that the temperature rise of the cooling liquid in the seal cavity is controlled within 22°C, and the shaft seal box pressure is about 0.17 MPa higher than the saturated vapor pressure of the medium. Optimize the cooling flush scheme to remove excess heat.

-Bonve Pump Bellows Seal-

Reverse-deduce the core fault from the wear state of the sealing face. The friction pair composed of the rotating and stationary rings is the core of the seal, and its wear marks can accurately reflect the situation: Severe wear on the outer diameter of the hard ring is mostly caused by an unevenly lapped sealing face or the presence of impurities; severe wear on the inner diameter is most likely caused by thermal deformation; if the wear width of the hard ring far exceeds that of the soft ring and there is continuous dripping during operation, it is necessary to check for poor pump alignment, shaft bending, bearing damage, and other issues.

Quickly locate from the leakage form. Slight leakage during the static test after installation is mostly caused by a faulty rotating/stationary ring seal; large leakage is most likely due to a problem with the friction pair. Leakage during trial operation, after excluding shaft system issues, is basically caused by damage to the friction pair, mostly due to cavitation, vaporization, or excessive compression. Sudden leakage during normal operation, apart from normal wear, is mostly caused by sudden changes in operating conditions or improper operation and maintenance.

The triggers of mechanical seal leakage are interlinked. Only by combining fault manifestations and performing multi-dimensional step-by-step investigations can you quickly find the culprit of leakage, solve the problem in a targeted manner, and ensure the long-term stable operation of the equipment.

Bonve pump always adheres to the philosophy of "Wholeheartedly Making Good Rotor Pumps," committed to providing global customers with customized conveying and mixing solutions. If you have technical inquiries, selection needs, case references, or other cooperation intentions related to Bonve rotor pumps, please feel free to contact us.