stem of the valve to be opened is centered under the circular part of the keyhole slot. The three keyhole slots are arranged in the sliding-bar to allow the opening of only one valve at a time. To position the sliding- bar, loosen the two locknuts and slide the bar through the oblong slots to the desired position and tighten the nuts. SPRAY SHIELDS Aluminized glass cloth spray shields are designed to prevent JP-5 from spraying on a hot surface or electrical equipment, or forming an atomized mist in the event of a gasket or strainer leak. In main and auxiliary machinery spaces, spray shields are installed on flanged valve (and valve man- ifold) bonnets, and flanged joints (including gage lines) on piping containing flammable fluid. For areas outside main and auxiliary machinery spaces, spray shields are installed on flammable fluid piping flanged valve bonnets and flanged joints located in the direct plane of an electrical switchboard, electrical equipment enclosure, or motor. In the event repairs are required to piping or valve flanges that are covered with spray shields, do NOT reuse spray shields that have fuel on them. FILTER/SEPARATORS There are several different types of filters in use in the service and transfer systems in the fleet. But, their principle of operation and hydraulic controls are similar. The major differences are their physical shape and flow direction. Filters are designed to remove 98% of all solids and 100% of all entrained water from the fuel passing through them. This is accomplished in a two-stage operation by two separate faltering media installed within the filter shell. The first stage consists of a bank of COALESCING elements, surrounded by a hydrophobic screen, that performs the function of removing solids and coalescing water. Coalescing means the bringing together of fine particles of en- trained water to form large droplets that then fall out of the fuel by gravity. The second stage consists of a bank of SEPARATOR elements that perform the function of repelling the coalesced water droplets that were too small to fall out by gravity. The filter is equipped with a float operated rotary control valve that will automatically drain the accumulated water from the filter sump and shut off the filter discharge if more water accumulates than can be drained off automatically. This section will describe typical filter/separators, their operation and maintenance, and their automatic control devices. Main Fuel (Service) Filters The body of the main fuel filter (fig. 4-23) con- sists of a cylindrically shaped shell with a dome- shaped head welded on each end. The dome-shaped heads provide a uniform flow into and out of the filter. The interior of the filter is divided into an inlet, fall-out, and outlet (clearwell) by tube sheets. TUBE SHEET.— The tube sheets are circular metal bulkheads installed within the filter shell where the dome-shaped heads are attached to the cylindrical shell. They are welded throughout their circumference to form a leakproof partition between the inlet, fallout, and outlet chambers of the filter. The tube sheets also provide the means of installing the filter element mounting assemblies (both coalescer and separator). Threaded holes, one for each assembly, are symmetrically arranged over the tube sheets surface. ELEMENT MOUNTING ASSEMBLY.— The element mounting assembly (fig. 4-24) consists’ of a perforated metal standpipe about 1 inch in diameter and 24 inches in length, and an end cap. One end of the standpipe is fitted with a threaded base cap to enable screwing it into the tube sheets. The opposite end is fitted with a threaded plug for attaching the end cap. The end cap is a metal disk about the same diameter as the elements. After the filter element has been placed over the standpipe, the end cap is secured in place by a threaded bolt. A metal washer and fiber washer are provided Figure 4-24.—Element mounting assembly. 4-27