STEAM- JACKETED KETTLESKettles require, as a minimum, monthly inspections.Figure 7-4 illustrates an arrangement of shipboardsteam-jacketed kettles. An annual preventivemaintenance inspection is also important. Here are afew factors to keep in mind while inspectingsteam-jacketed kettles.When making a MONTHLY inspection, check thedraw-off faucets, valves, and piping for leaks. Checkthe steam pressure-reducing valve to ensure it is in goodcondition and is functioning properly. Lubricate thehinges of the kettle cover with mineral oil.During the ANNUAL inspection, check each kettlefor leaks, cracks, and dents. Examine the cover, hinges,and latch for warp and alignment. Check the steampiping and the condensate piping, the valves, and thetraps for leaks and obstructions. Remove the safetyvalves; then clean, lubricate, and calibrate them beforereinstalling. Remove any rust and corrosion by usingNavy approved solvents. Other than visual inspections,each individual piece of galley equipment requires itsown type of preventive maintenance.During each ship’s regularly scheduled overhaul,steam-jacketed kettles should be tested using thefollowing procedure:1. Put each kettle into a cold-water pressure test of90 psi for not less than 30 minutes.2. Check the safety valves on each kettle. Thetesting of safety valves should he covered by the PMS.In general, kettle safety valves are set to release at apressure of 45 psig.3. Replace kettles that are cracked, badly pitted, orbulge under a pressure test.4. Replace all malfunctioning safety valves.Table 7-3 shows some common troubles and repairrecommendations on steam-jacketed kettles and othersteam-heated equipment.Table 7-3.—Common Troubles and Repair Recommendations on Steam-Jacketed Kettles and Other Steam-heated EquipmentInspection PointSteam jacketSteam jacketSteam jacketPipe jointsPipe jointsControl valvesControl valvesCondensate strainerSteam trapLaggingReducing valveSafety valveCoversDrawoff valveSymptomsNot beatingStays hotLeaksLeaksCorrosionStuck open or closedLeaks at stemNo flowMalfunctioningBroken or crushedIncorrect pressureStuck open or liftingunder pressureTight operationLeaksTimeWhen notedWhen notedMonthlyMonthlyMonthlyWhen notedWeeklyWhen notedEvery 6 monthsQuarterlyWhen notedWhen notedWhen notedWhen notedPossible Troubles/CausesNo steam; valve stuckclosed; trap malfunctioningValve partly open or scoredseatRapid changes in temperaturecausing cracks; faulty weldJoints made incorrectly; nottightLeaks or condensationNo steam or too much steam;packing too tight or valvefrozenPacking not tight enoughRestricted strainerParts dirty or wornWater soaked; stepped onParts dirty or wornLeaks or corrosionHinges dirtyScoredPossible CorrectionsCheck steam supply; freestuck valveRepair or replace valveRaise heat slower, reweldbust or crackUnscrew, clean and repairjointRepair and/or cleanLoosen packing gland or freefrozen valve stemTighten packingClean strainerDisassemble, clean, and repairReplace defective sectionsDisassemble, clean, andrepair; clean and adjustpressure every 6 monthsReplace or repair valveClean and lubricate bingesResurface or replace.DO NOT REPLACE WITHREGULAR GATE VALVE7-7
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