Military

Filter/separators remove solid contaminants and entrained water from liquid fuels. Those covered in this manual range in capacity from 15 GPM to 350 GPM. All filter/separators discussed in this manual use identical filter elements and canisters meeting the requirements of Military Specification MIL-F-52308. Filter elements and canisters are used in varying numbers depending on the flow rate of the specific filter/separator. Filter/separators must be used in varying numbers depending on the flow rate of the specific filter/separator. Filter/separators must be used when automotive gasoline or diesel fuel is pumped to the user’s refueling vehicles or when vehicles are refueled. They must also be used on all lines pumping aviation fuel directly to aircraft or to vehicles that refuel aircraft. In addition, all fuel loaded into aircraft refueling vehicles must be filtered again before it is pumped to aircraft.

Filter/separators help you keep product clean and water-free at the Class III supply point. The steps you should take to keep your filter/separators in good condition are outlined below:

• Test the accuracy of the pressure differential indicator once a year.
• Check the filter sumps each day, and remove any water you find.
• Keep a daily record of pressure differential readings. Pressure differential indicator readings should be kept in a daily log to determine when maintenance is needed. A suggested format for the daily log is shown in Figure 21-1. The pressure differential will vary slightly in day-to-day operations because of different pumping rates and differences within products. The pressure differential with a clean, new element is usually 2.5 PSI or less. It should increase slowly and gradually with use.
• Inspect the filter elements immediately if there is a sudden, significant drop in the pressure differential. It may mean that a filter element has ruptured.
• Check the new filter elements if there is no increase in the pressure differential after several months of operation. You may find that the elements are not properly installed or that some have ruptured.
• Change the filter elements at once when the reading on the pressure differential indicator is in the red (35 PSI and up). Change them at the end of the daily operation when the reading is in the yellow (20-35 PSI). When changing filter elements and canisters, always wear safety goggles and gloves to prevent fuel from contacting the eyes or skin.
• Change the filter elements at least every 24 months or when an inspection shows they are ruptured or not properly installed. Stencil the month and year the filter elements are changed on the top of the filter/separator.
• Check the performance of all filter/separators, regardless of product in service, every 30 days by submitting samples. Send the samples to a designated laboratory. Those not in use will be tested immediately before being placed in service and every 30 days thereafter while in use.

The standard filter/separator consists of a filter element and a canister assembly. The direction of the flow of fuel aids in the function of the filter/separator.

The standard filter element (NSN 4330-00-983-0998) fits inside the canister. The element is a perforated tube surrounded by a fiberglass filtering material, which in turn is wrapped with several layers of different materials. The fiberglass material filters solid particles from fuel. The outside of the element consists of layers of fiberglass, acetate, cotton knit, and fiberglass screen. This part coalesces (combines) fine particles of water in the fuel to form water droplets, which settle because they are heavier than the fuel. The service life of the standard filter element is 24 months.

The canister is a cylinder approximately 5 inches in diameter and 23 inches long. It consists of an outer and inner tube. The inner tube, made of perforated metal and a metal screen, supports the filter element. The outer tube is made of perforated metal lined with a nonsticking, metallic-coated screen. An end seal plate at the top of the canister can be taken off to reach the filter element.

Raw fuel enters the center tube of the filter element through a fitting at the bottom of the canister. Solid contaminates are removed as the fuel flows outward from the perforated center tube through the fiberglass filtering material. As the fuel passes through the outer layers of the element, fine particles of water in the fuel are coalesced into droplets. The fuel containing the coalesced water passes through the inner tube of the canister into the space between the inner and outer tubes. The metallic-coated screen of the outer tube does not allow water droplets to pass through it, and they fall to the bottom chamber of the filter/separator. Only clean fuel passes through the outer canister tube into the filter/separator tank. Figure 21-2 shows the flow of fuel through a 100-GPM filter/separator.

THE 15-GPM FILTER/SEPARATOR

The 15-GPM filter/separator is used with the 15-GPM, hand-operated dispensing pump. It may also be used to refuel light aircraft.

The 15-GPM filter/separator as shown in Figure 21-3 is a vertical, portable unit consisting of an aluminum tank mounted on an aluminum skid. The tank has fuel inlet and outlet valves, a water drain valve, and a water level sight gage. The fuel inlet and outlet valves are identical, 1-inch manually operated ball valves; they are attached near the bottom of the tank. Cam-locking couplings for 1-inch hose are provided at the inlet and outlet connections. The water drain valve is a ½-inch manually operated ball valve; it is also mounted near the bottom of the filter/separator. The water level sight gage consists of a plastic sight and a ball float; it is mounted on the side of the tank to show the water level in the base of the tank. This filter/separator contains a go/no-go fuse which shuts off the flow of fuel if water gets past the canister. The cover, held in place by four bolts, has a manually operated pressure vent valve to let air out of the unit. The filter/separator is 27½ inches high and weighs 20 pounds when empty. Its top working pressure is 25 PSI. The filter/separator must be grounded before it is used. Detailed information on the 15-GPM filter/separator is in TM 5-4330-230-12.

The 15-GPM filter/separator is used with the 15-GPM, hand-operated dispensing pump to pump fuel that must be free of solid contaminants and water. If no other aircraft refueling equipment is available, the 15-GPM pump and filter/separator may be used to refuel light aircraft.

The 50-GPM filter/separator is used with the 50-GPM pumping assembly. The type I model is intended for open field use. The type II model is intended for use with the tank and pump unit.

The 50-GPM filter/separator as shown in Figure 21-4 consists of an aluminum tank with a removable cover, an inlet pipe with dust plug, an outlet pipe with dust cap, a manually operated water drain valve, an air vent valve, a pressure differential indicator, and a sight glass. Four filter element and canister assemblies are installed on a mounting plate near the bottom of the tank. A float ball in the sight glass shows how much water is in the tank; the ball sinks in fuel and floats in water. The pressure differential indicator shows when the filter elements should be changed. The unit is 36 inches high, 20½ inches long, and 16 inches wide; it weighs 85 pounds. It has a flow rate of 50 GPM. The filter/separator must be grounded before use. A grounding rod and cable come with the unit. TM 5-4330-232-12 gives more information on the use and upkeep of the 50-GPM filter/separator.

The 50-GPM filter/separator is used with the 50-GPM pumping assembly in refueling systems at airfields and with equipment for servicing ground vehicles. The type I filter/separator as shown in Figure 21-4 is frame-mounted; it is intended for open field use. The type II model has no frame and is intended for use with the tank and pump unit.

The 100-GPM filter/separator is used with the 100-GPM pumping assembly. It is used mainly as part of the FARE system.

The 100-GPM filter/separator as shown in Figure 21-5 has an aluminum tank with a removable cover. Its female inlet has a dust plug, and its male outlet has a dust cap. Five filter elements, each in a canister, are set on a mounting plate near the bottom of the tank. The filter/separator is mounted on a tubular aluminum frame. The filter/separator has an air vent valve, a pressure differential indicator, a sight glass, and a manually operated water drain valve. A float ball in the sight glass shows how much water is in the tank. The ball sinks in fuel but floats in water. The pressure differential indicator shows when to change the filter elements. The flow rate of the filter/separator is 100 GPM, and its top working pressure is 75 PSI. The unit must be grounded before it is used. More information on the 100-GPM filter/separator is in TM 5-4330-217-12.

The 100-GPM filter/separator is used mainly with the 100-GPM pumping assembly as part of the FARE system. It is also issued as an individual item of equipment for use with various models of 100-GPM pumping assemblies.

The 350-GPM filter/separator has several uses. It is used with the FSSP or separately.

The 350-GPM filter/separator as shown in Figure 21-6 consists of an aluminum pressure tank with a removable head. The tank is welded on a tubular aluminum frame for support and protection. It has an inlet pipe through which unfiltered fuel enters, an outlet pipe through which the filtered fuel leaves, an internal inlet manifold, and risers for mounting 18 filter element and canister assemblies. The filter/separator also has an air vent valve so that air can be let out of the tank, a sight glass to show the water level by means of a float ball, and a manually operated water drain valve to drain water from the tank. A pressure differential indicator shows when the filter elements need to be changed. The filter/separator is 40 inches high, 47 inches long, and 33 inches wide; it weighs 375 pounds. It is designed for a flow rate of 350 GPM and a top working pressure of 150 PSI. The unit must be grounded before operation. TM 5-4330-211-12 has more information on the 350-GPM filter/separator.

The 350-GPM filter/separator is used in airfield refueling systems, motor fuel servicing equipment, and military hose line systems.

Figure 20-1. Suggested format for a filter/separator daily log