Chapter 7—AUXILIARY MACHINERY5. When the cooling water system of the com-pressor is being refilled, the water inlet valveshould be opened slightly to allow the water torise slowly in the cooler shell and water jackets.Also, the vent valves which are fitted to the waterspaces should be opened to permit entrapped airto escape, and thus prevent the formation of airpockets in the system.CARE AND MAINTENANCE OFAIR SYSTEM EQUIPMENTThe air flasks and separators of surface shipsmust be given a surface inspection every 3 monthsto determine if there is any external corrosion ordamage to flasks or piping.Because of the coating of zinc chromateprimer, corrosion is seldom a source of troubleon the internal surfaces of air flasks; however,corrosion may take place on the external surfacesof air flasks and may be sufficiently serious toweaken the material, especially in high-pressureflasks. Surface corrosion usually occurs at pointswhich cannot be easily reached for propercleaning and painting.Drainage of air system equipment must be suf-ficiently frequent to prevent excessive accumula-tions of moisture and oil. Such accumulations notonly cause internal corrosion and fouling ofmoving parts, but also create a serious hazardsince any excessive oil accumulation may resultin an explosion.All high-pressure flasks and separators mustbe inspected, cleaned, tested, and repainted atprescribed intervals by a repair activity. For sur-face ships, the initial and subsequent intervalsshould not exceed 6 years. Although inspectionintervals for separator flasks are approximately3 years, if there is reason to believe that seriouscorrosion of either the exterior or the interior ofair flasks is taking place, before the lapse of thenormal interval, the flasks should be inspected andtested at once.Periodic examinations are essential to deter-mine the condition of air system equipment; theseexaminations should include not only a completeinspection of the interior and the exterior of flasksand separators, but also ultrasonic inspections andhydrostatic tests. After a thorough cleaning, theflasks which successfully pass the hydrostatic testare given the prescribed internal protectivecoating, and when necessary, the exterior ispainted. Further information on the details of theinspections and maintenance performed by repairactivities can be found in chapter 551, sectionVIII, of Naval Ships’ Technical Manual.INSPECTIONS AND TESTSThe minimum maintenance requirements forthe performance of inspections and tests of com-pressed air plants are given in figure 7-1. It is theresponsibility of the engineer officer to determineif the condition of the equipment, hours ofservice, or operating conditions necessitate morefrequent inspections and tests. Details for eachtest and inspection are obtained from the PMSManual, or the appropriate manufacturer’stechnical manual.SAFETY PRECAUTIONSCompetent personnel operating and maintain-ing any machine keep it performing as efficientlyas possible. In order to achieve peak performancefrom a compressed air plant, they take steps toprevent or minimize the occurrence of any con-dition which might reduce plant capacity or resultin serious damage. All personnel should take everypossible precaution to prevent potential explo-sions, especially when operating high pressuresystems. Safety precautions which will aid you inpreventing explosions and in maintaining a plantin satisfactory operating condition are listedbelow.1. Minimize the possibility of explosions inan air compressor, discharge line, or receiver bytaking steps to prevent or eliminate the following:a. Dust-laden intake air.b. Presence of oil vapor in compressor orreceiver.c. Leaking or dirty valves.2. Make sure that the compressor intakereceives only cool, dry air.3. Use only prescribed agents for cleaningcompressor intake filters, cylinders, or airpassages. DO NOT use benzene, kerosene, or7-5
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business