LESSON 2

SUPERVISE THE OPERATION OF FILTER/SEPARATORS

Supervision of the performance of Preventive Maintenance Checks and Service (PMCS) of pumps, filter/separators, and related equipment includes preparation of advance sheets and observation of proper safety precautions.

This lesson covers the PMCS of pumps, filter/separators, and related equipment.

Terminal Learning Objective:

INTRODUCTION

Pumping units and filter/separators are widely used throughout the theater. Pumping units serve as a primary means for the receipt, storage, and issue of petroleum fuels during bulk and retail Class III operations. Filter/separators provide an effective means for insuring that fuels are free from contamination. As an NCO there are several assignments that require knowledge of maintaining this equipment.

PART A - USE OF FILTER/SEPARATORS

Filter/separators (Figure 2-1, and 2-2) remove solid contaminants and entrained water from liquid fuels. Filter/separators range in size from 15-GPM to 600-GPM capacity. Organizational maintenance personnel are responsible (with the help of the equipment operators) for replacing the filter elements in all filter/separators. The use of standard interchangeable elements and canisters make it simple to replace elements in filter/separators. They may be used when ground product, such as automotive gasoline and diesel fuel, are pumped to the user’s vehicles. They must be used on all lines pumping fuel directly to aircraft and to vehicles that refuel aircraft. In addition, all fuel loaded into aircraft refueling vehicles should be filtered again before it is pumped to aircraft.

The standard filter element fits inside the canister. It is a perforated tube surrounded by a fiberglass filtering material, which in turn is wrapped with several layers of different material. The fiberglass material filters solid particles from fuel. The cotton knit and fiberglass screen and combine fine particles of water in fuel to form water droplets which settle because they are heavier than fuel. The expected 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 is made of perforated metal and metal screen. The outer tube is made of perforated metal lined with a Teflon coated screen.

Raw fuel enters the center tube of the filter element through a fitting at the bottom of the canister. Solid contaminants 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 to the space between the inner and outer tubes. The Teflon coated screen of the outer tube throws off water droplets, 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. Tank vehicles such as the M131A5C tank semitrailer have filter/separators that work in three stages. The first stage has 15 filter elements that remove solid contaminants. The second stage has five canisters to separate water from fuel and let water drain into the sump. The third stage has 15 go/no go fuses. They shut off the flow of fuel if the other two stages allow water or contaminants to exceed a safe level. M49AC filter/separators have three filter elements, three separator canisters, and three go/no go fuses. The go/no go fuses automatically shut off the flow of fuel if the water and/or contaminants reach a high level.

Performing Before Operational Maintenance.

• Make a visual check for leaks and for loose or missing parts in cover assembly and other connections.
• Ensure that all valves operate freely and do not leak. Ensure drain valves are in closed position.
• Ensure the ground wire is connected properly and is not broken.
• Ensure gaskets are in place and not leaking.
• Ensure a fire extinguisher is easily accessible and in working order.

Performing During Operational Maintenance.

• Check the pressure gage reading to ensure pressure reading is below the red band on the gage. If it is in the yellow band change elements after the operation. (If in the red stop operation).
• Check the water level sight gage and drain the water if necessary.
• Check the filter separator for leaks.

Figure 2-1. Typical flow through a filter/separator.

Performing After Operational Maintenance.

• Clean and store the equipment.
• Ensure all dust caps and plugs are installed after the operation.

• 15 GPM liquid fuel filter separator is a vertical, portable unit consisting of an aluminum tank mounted on an aluminum skid. This tank has fuel inlet and outlet valves, a water drain valve, and a water level sight gage. The pressure vent valve’s working pressure is 25 psi. The 15 GPM filter separator is used with the 15 GPM hand operated dispensing pump.
• 50 GPM filter separator consists of an aluminum tank with removable cover, inlet pipe with dust plug, outlet pipe with dust cap, water drain valve, an air vent valve, a pressure differential indicator, eight glass, four elements and a canister. A reading in the green (0-20 psi) means the elements are clean. A reading in the yellow (20-35 psi) means the elements must be changed at the end of the day’s operations. A reading in the red (35 psi and up) means the elements must be changed at once. The maximum working pressure is 75 psi. It is used in refueling systems and for servicing ground vehicles.
• 100 GPM filter separator, aluminum pressure tank with removable head. The tank is welded in a tubular aluminum frame. The maximum working pressure is 75 psi.
• The 350 GPM filter separator is used in the 150 psi airfield refueling systems, motor fuel servicing equipment and military hoseline systems, and as a component of the FSSP.

Figure 2-2. M969 and M970 Tank Truck Filter/Separator

PART B - DIFFERENT TYPES OF PUMPS AND THEIR CHARACTERISTICS

The 50 GPM pumping assembly (Figure 2-3) consists of a pump and engine assembly mounted on an oval aluminum base. A one cylinder four-cycle air cooled gasoline engine is used to power the pump. The pump is a self-priming, centrifugal pump. The pump suction and discharge port have 1 1/2-inch cam locking coupling adapters with dust caps.

Figure 2-3. 50-GPM pumping assembly.

The 100 GPM pumping assembly (Figure 2-4) is used as a component of the FARE system. An air cooled, one cylinder, gasoline driven, four cycle engine is used to power the pump. It develops 2 1/2 horsepower at 3,500 RPM. The 100 GPM pumping assembly is used to transfer fuel from storage tanks, tank cars, and tank vehicles to smaller capacity containers.

Figure 2-4. 100-GPM pumping assembly.

The 350 GPM pumping assembly (Figure 2-5) is used mainly with the fuel system supply point (FSSP).

Towing speeds.

Gasoline Models (350 GPM)

• Barnes Model, Idle speed 700-800 RPMs. The normal operational speed 3200-3600 RPMs.
• Gormann Rupp Model, Idle speed 1000 RPMs. The normal operational speed 220-2350 .

Diesel Models. The 350 GPM pumping assembly is designed specifically to transfer gasoline, jet fuels, light liquid petroleum fuels and water. It consists of an air cooled, three cylinder diesel engine and a self priming centrifugal pump mounted on a two wheel frame assembly .

• Model 1322021070 (97403). This model is used to transfer fuel only and does not have a regulator. It is manually controlled and has a recommended warm up and cool down time of 2 minutes.
• Model 13226E2289 (97403). This model is used to transfer fuel only and has a regulator that provides manual and automatic modes of operation.
• Model 13225E9200 (97403). This model is used to transfer water only and does not have a regulator.

Figure 2-5. 350-GPM pumping assembly.

Practice Exercise