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
