system to filter the fuel from the contamination tanks before pumping it back into storage tanks. These filters normally have a rated capacity of 300 gpm and an operating pressure of 100 psi. The filter is designed to remove 98% by weight all sol- ids 5 microns or larger, and 99.9% of the water. The filter has a cylindrically shaped, welded, copper- nickel shell mounted on three legs. A bolted hand- hole cover assembly at the top of the shell provides access to remove or replace coalescer or separator elements. The interior of the shell is divided into three chambers: inlet, fallout, and outlet. The inlet chamber is at the bottom of the shell; the fallout chamber contains coalescer and separator elements: and the outlet chamber (clearwell) connects to the discharge piping. The outside of the shell contains a reflex-type sight glass, differential gage, and an outlet pressure gage. The sight glass indicates water level in the fallout chamber. The differential gage indicates the pressure drop across the coalescer elements. The out- let gage indicates the pressure of the filtered fuel after it has passed through the separator elements and be- fore it leaves the filter. There are 18 coalescer elements mounted verti- cally on the horizontal deck plate. Fuel flows from the inlet chamber through the coalescer elements to the fallout chamber. There are 11 separator elements mounted hori- zontally in individual mounting assemblies attached to the outlet chamber. Fuel flows from the fallout chamber, through the separator elements, and into the outlet chamber. A float control valve, bolted to a flange that is welded to the shell, controls the action of an automatic water discharge valve and an automatic shutoff valve in the exact way as the vertical filter. In fact, with the exception of rated capacity, this filter operates exactly the same as the vertical filter. Prefilters Prefilters are provided upstream of first-stage fil- ters to reduce the burden on and extend the life of the coalescer elements installed in first-stage filters. Ba- sically, the prefilter consists of a cylindrical housing with valved vent and drain connections, and a differ- ential pressure gage. The elements are a disposable type designed to remove solid contaminants. CENTRIFUGAL PURIFIER Centrifugal force is defined as that force which impels a thing (and any or all of its parts) outward from a center of rotation. Every time you lean in as you take a fast turn, you are counterbalancing cen- trifugal force. How far in you lean is determined by the amount of centrifugal force exerted in the turn. Most people do it automatically, for centrifugal force, along with gravity, is the most prevalent physical force exerted upon us and upon all matter. The purpose of the centrifugal purifier (fig. 4-26) in the JP-5 filling and transfer system is to separate and remove water, solids, and emulsions from JP-5 during transfer from storage to service tanks. The diskbowl centrifuge is a “constant effi- ciency” type of separator; that is, it achieves the same degree of efficiency at the end of a run as at the beginning. The reason for the constant effi- ciency is that accumulated solids are stowed away from the separation zone. Separation occurs within the disk spaces, and the separated liquids are dis- charged from outlets that are removed from inter- ference of the stowed solids. Theory of Operation Dirty fuel containing water and solids is fed to the purifier through the feed inlet of the inlet-outlet assembly. The dirty fuel then enters the top of the bowl centrifuge through the feed tube and travels down the tubular shaft, to be thrown outward and upward by the distribution cone at the bottom of the distributor, under the disk stack. The fuel is forced upward through the distribution holes in the inter- mediate disks, where centrifuge action separates the fuel, water, and solids. The solids are thrown directly against the bowl wall and collect in a uniform layer on the inside vertical surface of the bowl shell. The water, thrown outward, is displaced by incoming feed material forc- ing the water overflow up and over the outer edge of the top disk, and discharging it through the discharge ring and the heavy phase outlet. The clean fuel, which has a lesser density, is displaced inward and upward along the outside of the distributor to the paring disk chamber, where the spin- ning fuel contacts the edge of the stationary paring disk. The paring disk then acts as a pump, discharging the fuel to the purifier fuel outlet. 4-32