stacks, to determine the true state of combustionefficiency.NOTE: In boilers using distillate fuel, excess aircan cause abnormally high superheater outlettemperatures, especially on “D” type boilers. Be verycareful to prevent leakage of air into a boiler. Air thatenters a boiler at any place other than through a burnerregister does not contribute to furnace combusiton andmay reduce combustion efficiency.. Watch carefully for chloride contamination of thewater in the boiler feed and condensate systems; itthreatens the material integrity and operationalreadiness of the plant. Keep in good working order thosemeans used to determine the chloride content of boilerwater. Drill operating personnel frequently on thedanger of, and the methods used to prevent, chloridecontamination. Be sure the DFT is functioning properlyto remove dissolved gases from the boiler feedwater.l Conduct daily dissolved oxygen tests on water tosteaming boilers and on the discharge side DFT if yourship has them. You don’t want dissolved oxygen in anyboiler, but it is particularly corrosive in boilers thatoperate at high pressures and high temperatures. Themodern pressure-closed feed system is designed to keepthe condensate and feedwater from being exposed to air,and the DFT is designed to remove a great deal ofoxygen that becomes dissolved or entrained in the water.However, there are still many ways in which oxygen canget into the system and become dissolved in the water.For example, a defective DFT may allow the water topass through without being deaerated. Incorrectoperation of a DFT can have the same effect. Air canleak into the condensate and feed systems at variouspoints and its oxygen can dissolve in the water. Failureto lay up idle boilers according to prescribed proceduresis still another cause of dissolved oxygen. You can findmore information on dissolved oxygen tests in NSTM,chapter 220.. The Oil King and the engineering watchsupervisors in the fireroom should be graduates of theBoiler Feedwater Test and Treatment Course. Theyshould be certified to perform the feedwater tests andtreatments that are prescribed by Naval Sea SystemsCommand (NAVSEASYSCOM) and the manufacturerof the boilers. Never assume that personnel who conductthese tests are competent, observe them personally andbe sure.. Always preheat the lubricating oil system beforestarting the engines. During operating periods, keep theoil from the oil cooler between 120 and 130 degrees tominimize bearing wear. Watch for overheated bearings,foaming or emulsified oil, the presence of bearing metaland other foreign particles in lubricating oil sumps, andthe presence of rust on journals and gearing.. When condensers and their auxiliarycomponents are operated improperly, they can causeextensive loss of efficiency. Here are several examples.——lWhen you use more than the required amount ofcooling water, the condensate system pumps alarge amount of heat overboard, and the boilerswill have to replenish that lost heat. You’ll get thesame effect from recirculation of the condensate.Air leaks in the condenser or its components mayoverload the air ejectors and lower the vacuum.Steam is wasted by fluctuating, or excess, steampressure to the air ejectors and by steam-drivenauxiliary pumps operated at higher-than-necessary speeds.When the weather is cold enough to requiresteam heat, try to operate ventilation motors in fresh airsupply systems at slow speeds. If you must operate themat higher speeds, first secure the steam to preheater andreheaters, but never operate supply blower motors fasterthan necessary for comfort. It is usually more efficientto circulate fresh air in a compartment by operating theexhaust blower at a faster speed.. Keep engineering spaces, equipment, andmachinery clean–it is one of the most important soundengineering practices. Clean up trash and spilled oil toprevent accidents and fire. Keep machinery free of oiland dirt so oil and fuel leaks are easily visible. Repairall leaks promptly. NEVER hose down spaces above thelevel of the bilge deck plates–you may get water inelectrical assemblies. Clean spaces, equipment, andmachinery show pride in your work and your ship.You can find information on performance data andoperating limits of the plant’s equipment and machineryin the NSTM, manufacturers’ technical manuals, and theShip Information Book (SIB). For older ships, look inthe General Information Book, the Piping SystemInstruction Book, the Record of Electrical Installations,the Electrically Operated Auxiliaries WithPerformance Data, and General Description ofElectronics System Installation.4-3
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