DEMINERALIZER

pressure on the pump suction pressure gauge. If flow doesn’t develop, check for clogging and wear. You should not operate a pump without collant flow. Some pumps have a small recirculating line that enables the pump to recirculate coolant from the discharge side of the pump to the suction side. ‘This provides for a flow of coolant through the pump if an inlet/outlet valve to the pump is closed with the pump running. Whatever the case, you should keep in mind that the operation of a pump without the normal flow of coolant through it will result in overheating and seizure of the pump. Corrective maintenance of the circulating pump consists of repairing leaks, replacement of the mechanical seal, and cleaning the internal parts. This type of maintenance is performed by personnel of the ship’s engineering department. You should provide assistance if it is needed. DEMINERALIZER The secondary cooling system water purity is maintained in an ultrapure state by a demineralizer. By maintaining the coolant at a high degree of purity, you minimize corrosion and the formation of scale on the radar unit. Corrosion or scale on a high-heat-density component such as waveguide dummy loads and klystrons results in the formation of a thermal barrier. The thermal barrier reduces the effectiveness of heat transfer at normal operating temperatures. This leads to premature failure of the components. The demineralize (figs. 1-6, 1-7, and 1-8) is connected between the secondary cooling system supply and return lines to circulate water through it. The demineralize is sized so that 5% of the cooling system volume passes through the demineralize every hour. The coolant is purified by organic compound adsorption (if required), oxygen removal, ion exchange processes, and submicron filtration. Shown in figure 1-25 is a typical three-cartridge demineralize. Some demineralizes use only two cartridges; one of the cartridges is a combination cartridge that provides organic compound adsorption, if it is required. The input supply valve to the demineralize unit, depicted in figure 1-25, must be adjusted on system start-up, and periodically thereafter to maintain the Figure 1-25.—Deminerlaizer. 1-20