Describe the safe isolation procedure of centrifuges before maintenance and the maintenance schedule with brief procedure for satisfactory operation?

flowchart TD
    A[Stop centrifuge] --> B[Isolate electrical supply with lock-off]
    B --> C[Close feed and discharge valves]
    C --> D[Drain bowl and pipes]
    D --> E[Vent to atmosphere]
    E --> F[Confirm zero energy]
    F --> G[Tag all isolation points]
    G --> H[Issue permit-to-work]
    H --> I[Start maintenance]

• Isolation sequence: stop → isolate electrical supply with lock-off → close feed and discharge valves → drain and vent → confirm zero energy → tag → permit-to-work
• Centrifuge types: clarifier (single oil outlet) and purifier (separate water discharge, gravity/dam ring sets oil-water interface)
• Critical check: bowl must be primed with water seal each run; wrong gravity disc causes oil to pass to water side
• Maintenance trigger: calendar intervals, running hours, sludge build-up, falling separation efficiency
• Records: permit-to-work, PMS job card, maintenance log
• Governing instruments: TEAP Part B §9.1 (safe isolation), ILO Safety and Health in Ports §247 and 6.1.6 (isolation + lock-off + permit), ISM Code §10 (maintenance procedures), UK Code of Safe Working Practices §18.25.2 (isolate and depressurise), MS Act 2025 (Indian flag)
• EOOW role: carries out isolation under permit, performs scheduled maintenance, reports non-conformities, records in PMS