What are the common mechanical seal failures in SLG vertical pipeline pumps

Mechanical Seal Leakage

Mechanical seal leakage is the most common failure in vertical pipeline pumps. Leakage may occur during initial pump start-up or after long-term operation. Main causes include seal face wear, aging of seal materials, installation misalignment, and pump shaft vibration. Leakage not only causes fluid loss but also poses safety risks, especially in corrosive environments such as chemical or petroleum applications, accelerating equipment damage and affecting system stability.

Dry Running and Seal Wear

Dry running occurs when the mechanical seal operates without sufficient liquid lubrication, causing direct contact between the seal face and metal surfaces. Insufficient pump liquid, air ingress in the suction line, or low system pressure can all lead to dry running. This significantly reduces seal life and may damage the pump shaft or casing, increasing maintenance costs.

Mechanical Seal Overheating

Overheating of the mechanical seal typically manifests as abnormal temperature rise in the seal chamber. Causes include excessive pump speed, high flow rates, inadequate cooling water, or improper seal chamber design. Prolonged overheating can deform seal materials, fatigue springs, or cause carbonization, accelerating seal failure. High-temperature environments may also result in medium leakage, affecting pump station safety.

Vibration-Induced Damage

Pump shaft vibration is a major factor causing mechanical seal failure. Misalignment of the shaft, unbalanced impellers, or pipeline shocks generate seal face vibration. This can lead to localized wear, spring loosening, or seal assembly breakage. Vibration reduces seal performance while increasing noise and energy consumption.

Spring Failure and Seal Face Misalignment

Internal springs are crucial for maintaining seal face contact. Spring failure, corrosion, or improper installation may cause misalignment or uneven contact of the seal face. This results in intermittent or continuous leakage and requires pump disassembly for inspection and repair.

Chemical Corrosion and Material Mismatch

In chemical, wastewater, or strong acid/alkali environments, improper seal material selection can cause corrosion. Corrosion damages the seal face smoothness, creating micro-gaps that lead to leakage. Using corrosion-resistant materials such as silicon carbide, fluororubber, or ceramic seal faces can effectively reduce these failures.

Improper Installation

Seal installation accuracy directly affects pump reliability. Non-vertical installation, unclean sealing surfaces, or incorrect tightening of seal components can cause failures. Improper installation may result in face eccentricity, spring failure, or localized wear, reducing pump efficiency and increasing failure rate.

Fatigue Failure from Long-Term Operation

Continuous operation over extended periods can cause fatigue in mechanical seals. Signs include seal face wear, spring relaxation, and packing aging. Fatigue failure is often difficult to detect early, highlighting the importance of regular monitoring and maintenance of the pump seal.

Uneven Seal Chamber Flushing

Mechanical seals rely on liquid flushing to lubricate and cool the seal face. Uneven flushing or insufficient flow can cause local overheating or dry running. Uneven flushing may also create micro-grooves or cavitation on the seal face, accelerating failure.

Impact of Seal Failure on the System

Mechanical seal failure affects not only the pump but also the entire system. Leakage can reduce pump efficiency, increase energy consumption, and lead to pipe corrosion, environmental contamination, and safety hazards. Timely detection and maintenance of mechanical seal issues are critical to ensure long-term stable operation of SLG vertical pipeline pumps.

Maintenance and Preventive Measures

Regular inspection of seal faces, springs, and lubrication conditions is key to extending mechanical seal life. Selecting proper seal materials and types, ensuring precise shaft alignment, and maintaining adequate seal chamber flushing can effectively reduce failures. Establishing seal monitoring and inspection routines helps detect leakage or abnormal vibration early, lowering maintenance costs and improving pump system reliability.