DEMINERALIZERS

through it will result in overheating and seizure of the This type of maintenance is normally performed pump. Included in the corrective maintenance of the by the ship’s engineering department; you should circulating pump are repairing any leaks, replacing the provide assistance if it is needed. Figure 2-19 shows mechanical seal, and cleaning the internal parts. a distilled-water circulating pump. Figure 2-19.—Distilled-water circulating pump. DEMINERALIZERS Demineralizes are used to maintain the secondary cooling system’s water purity in an ultrapure state. By maintaining the coolant at a high degree of purity, corrosion and scale formation is minimized on the radar unit. Corrosion or scale on high-heat-density compo- nents, such as waveguide dummy loads and klystrons, results in the formation of a thermal barrier. The ther- mal barrier reduces the effectiveness of heat transfer at normal operating temperatures, which, in turn, leads to premature failure of the components. The demineralizer is connected between the sec- ondary cooling system supply and return lines to cir- culate water through it. The demineralizer is sized so that 5 percent of the cooling system volume passes through the demineralizer every hour. The coolant is purified by organic compound adsorption (if re- quired), oxygen removal, ion exchange processes, and submicron filtration. Figure 2-20 shows a typical three-cartridge demin- eralizer. Some demineralizers use only two cartridges, with one of the cartridges being a combination car- tridge that provides organic compound adsorption, if it is required. 2-20