Fuel-Handling Vehicle

Fuel-handling vehicles are classified as fuel tank trucks or fuel tank semitrailers. Each vehicle has distinguishing characteristics (model, size, and capacity). The purpose of fuel-handling vehicles is to load, haul, and discharge fuel to other vehicles, aircraft, or fuel depots.

DESCRIPTION.- A typical fuel tank truck is equipped with a tank body divided into compartments. Each compartment has a manhole and filler cover assembly, bottom sump or well, and discharge valves with screen assemblies and drainpipes. The drainpipes end in a manifold in the equipment Compartment. The compartment (fig. 6-19) also houses a delivery pump, a discharge valve control assembly, a pump delivery line gate valve, an automatic dump valve, drain tube valves, a gravity line gate valve, a filter separator, a pressure gate, a meter, a water separator chamber, and a grounding cable.

The delivery pump is powered by the power takeoff (PTO), which is controlled by the PTO lever located in the cab of the truck. The lever is moved backward to the ENGAGED position to engage the PTO which causes the pump to operate. The lever is moved forward to the DISENGAGED position to disengage the PTO and to stop the pump.

The discharge valve control assembly levers control the discharge valves located at the bottom of each tank

Figure 6-19.-Dispensing equipment compartment.

compartment. Pulling back on a lever opens a discharge valve and permits the flow of fuel into the piping system. Squeezing the trip rod operation handle mounted on the lever and moving the lever forward locks the compartment valve and shuts off the flow of fuel. In an emergency, the discharge valve remote control lever, located on the left side of the discharge valve control operating lever bank, provides a means of locking all discharge valves. Pulling the handle causes a release lever to trip the operating levers and locks the valves.

OPERATION.- When operating the fuel tank truck for discharging fuels, follow instructions prescribed in the manufacturer's operating manual. The general instructions which follow are typical of the type of fuel tank truck used in the NCF.

Tank trucks are used to haul and dispense fuels. (See fig. 6-20.) The tank truck shown is equipped with a stainless steel, 1,200-gallon tank body, which is divided into two 600-gallon compartments (fig. 6-21). The fuel delivery system is equipped with an upright filter/separator and meter. Since there are only two tank compartments, the discharge valve control has two operating levers, as shown in figure 6-21. There is a speed control linkage assembly that controls the speed of the engine, power takeoff, and delivery pump. The filter/separator in figure 6-21 is equipped with three filter elements, three go no-go fuses, a pressure gauge, and an automatic dump (drain) valve. The primary function of the filter element is to collect solid contaminants and separate water from the fuel.

The go no-go fuses shut off the fuel flow if water or solid contaminants exceed a safe level; the shutoff of fuel flow indicates the falters are not operating properly. If such a malfunction exists, it must be located and corrected and the fuses replaced before operation is continued.

The automatic dump (drain) valve is float-operated. The float sinks in fuel but rises in water. When water is present in the valve housing, the float rises, the valve opens, and the water drains away through the valve drain tube. Open the automatic dump (drain) valve during fueling operations. Check the pressure differential every day that equipment is in use and while the pump is operating.

Close the meter drain valve, delivery pump drain cock, and filter/separator drain valve. Open the automatic dump (drain) valve. Enter the driver 'S compartment and start the engine; depress the clutch, and put the transfer case shift lever in NEUTRAL; place the PTO lever in the ENGAGED position; then place the transmission gearshift lever in the gear position recommended by the manufacturer, and release the clutch.

Figure 6-20.-Fuel-service truck.

Figure 6-21.-Fuel-service truck diagram.

CAUTION

Allowing the engine to run with the transmission engaged and the transfer case shift lever in NEUTRAL without the PTO in the ENGAGE position will cause bearing failure in _{the transfer case.} Be sure to shift the transmission gearshift lever to NEUTRAL when not operating the power takeoff.

After the fuel dispensing pump is engaged set the throttle rpm to the manufacturer's recommended setting. Move the discharge valve control levers to the open position; and be sure, before pumping operations begin, to attach the grounding wire to the vehicle being serviced. Open the pump delivery line hose and squeeze the nozzle operating lever to discharge the fuel.

After discharging the fuel, close the pump delivery line gate valve, and move the discharge valve control operating lever to the CLOSED position.TIhen close the automatic dump valve drain tube valve. Return to the driver's compartment; set the rpms to idle, depress the clutch and place the transmission gearshift lever in NEUTRAL; then place the transfer power takeoff shifting lever to DISENGAGED, and stop the engine.

When changing from one type of fuel to another, drain and flush the fuel compartments, pump filter/separator, service lines, manifold, meter, gauge, and dispensing hoses and nozzles.

NOTE: All pumping mechanisms are not controlled and operated in the same manner. Each make or model operates differently. If you are in doubt as to the proper pump operation and maintenance procedures, study the operator's manual and the caution and instruction plates located near the pump and control mechanisms.