01
Cavitation and Impeller Erosion
Cavitation occurs when inlet pressure drops below the vapor pressure of the pumped fluid, causing vapor bubbles to form and collapse violently on impeller surfaces. This creates pitting, blade thinning, and progressive loss of hydraulic efficiency. Root causes include low inlet head, high suction line velocities, or discharge blockage that forces backflow. Failure progresses as metal loss accelerates, reducing flow and increasing vibration until the impeller becomes unbalanced and damages bearings. EGR inspects impeller blades with precision measurement, assesses material loss depth, and replaces the impeller with OEM-matched components, then performs full dynamic balancing before return to service.
02
Mechanical Seal Degradation and Leakage
Mechanical seals operate under high pressure and temperature differentials, relying on precise face contact between rotating and stationary rings. Seal face wear, elastomer hardening, or spring relaxation breaks the seal interface, allowing process fluid to leak past the seal assembly. Root causes include contaminated cooling water, thermal cycling in high-temperature applications, or misalignment under system vibration. Failure manifests as slow weeping that escalates to heavy dripping, allowing fluid loss and bearing contamination. EGR removes the seal assembly, inspects both rotating and stationary faces for wear and deposits, replaces elastomers and springs, and pressure-tests the new seal assembly on the pump before shipping.
03
Bearing Failure and Radial/Thrust Load Damage
Centrifugal pumps generate significant radial forces perpendicular to the pump shaft due to fluid flow dynamics, and multistage units create substantial axial thrust loads. Bearing raceways develop spalling, rolling elements fracture, and corrosion (fretting) occurs at the shaft/bearing interference fit under load cycling. Root causes include inadequate lubrication, contaminated bearing grease, misalignment that loads one bearing more heavily, or oversized thrust loads in vertical turbine configurations. Failure escalates as spall growth increases friction and heat, eventually seizing the bearing and scoring the shaft. EGR removes bearings, performs ultrasonic and magnetic particle inspection of the shaft, replaces bearings with OEM specifications, verifies shaft runout, and tests for smooth rotation.
04
Housing Cracks and Casting Porosity
Pump casings experience internal pressure cycling and thermal stress during operation. Small casting defects (porosity, inclusions) propagate as fatigue cracks, typically developing at stress concentrations around suction/discharge ports or along split faces in split-case designs. Cracks cause external leakage, loss of pressure containment, and potential safety hazards. Root causes include pressure spikes from discharge blockage, thermal shock from sudden flow stoppage, or original material defects. Failure progresses as cracks grow under operational stress until leakage becomes uncontainable. EGR performs ultrasonic and liquid penetrant inspection to map crack location and depth, applies precision welding with post-weld stress relief for critical repairs, grinds and polishes surfaces, and hydro-tests the housing before reassembly.
