On-site flushing 2–7 days

Lube Oil Flushing

ISO 4406 Cleanliness Class 16/14/11: Certified Before Oil-In

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16/14/11

ISO 4406 Target Class

6,000 L/min

Max System Flow Rate

3μm

Final Filtration Rating

100%

Lab-Certified Particle Count

Why Our Engineers

New and recently overhauled turbines are destroyed by construction debris (weld slag, pipe scale, sand, and metal swarf) within hours of first startup. Oil flushing is not optional: it is the single most cost-effective insurance against a catastrophic bearing failure on a brand-new overhaul.

Overview

Lube oil system contamination is the primary cause of bearing failures in new and recently overhauled turbines. Construction debris entering the lube oil system during installation or overhaul can destroy bearings and journal surfaces within hours of startup. Keshav Enterprises performs professional lube oil flushing using purpose-built mobile centrifuge filter systems to achieve ISO 4406:99 cleanliness class 16/14/11 (the minimum standard for steam turbine bearing lubrication). Our process is fully documented: oil sample results at every stage, progressive filter upgrade records, and a final laboratory-certified particle count certificate are provided before the system is handed back for oil-in.

Our Process

System Survey & Flushing Plan

Review of system P&ID, oil volume, pipe bore sizes, heat exchanger configuration, and bearing housing layout. Development of flushing flow path using hydraulic calculations to achieve turbulent flow (Reynolds number above 4,000) in every pipe section. Temporary bypass spools and blind flanges identified and designed where required.

Temporary Flushing Circuit Installation

Installation of temporary bypass pipework around bearings, control valves, instrumentation, and other sensitive equipment that must not see flush debris. Connection of mobile flushing unit. Installation of temporary wire mesh target strainers at flush return points for debris monitoring.

Initial Flush: High Flow Rate

System charged with flushing oil (or process oil if compatible). Flushing pump operated at maximum achievable flow rate for maximum turbulence. Oil temperature thermally cycled between 30°C and 70°C at 30-minute intervals, because thermal cycling stresses pipe walls and dislodges adhered scale and debris. Target strainers inspected and cleaned at each interval.

Contamination Monitoring & Particle Count

Oil samples drawn per ISO 4021 clean sample extraction procedure at each stage. Particle count measured using automatic particle counter per ISO 11500, reporting counts at ≥4μm, ≥6μm, ≥14μm, and ≥21μm. Results plotted on a cleanliness progress chart against the ISO 4406 target class.

Progressive Filter Upgrade

As gross contamination is removed, filter element micron rating progressively reduced through stages: 25μm → 10μm → 6μm → 3μm absolute. Centrifuge de-watering unit operated continuously throughout flushing to remove free and emulsified water. Karl Fischer water content tested to confirm de-watering effectiveness.

Final Acceptance Particle Count

Minimum three consecutive clean oil samples drawn at intervals must all achieve the target ISO 4406 class 16/14/11. Final samples submitted to accredited laboratory for independent verification. Written certificate of oil cleanliness (signed, stamped, and traceable to the laboratory) issued to client.

System Restoration & Oil Fill

All temporary bypass spools and blind flanges removed. All bearings, sensitive instruments, and critical equipment reconnected. System refilled with filtered, new process oil passed through a 3μm absolute filter during filling. Final particle count on system oil after fill confirms target maintained. System handed over for startup.