LESSON 4

SUPERVISE PETROLEUM TANK VEHICLE OPERATIONS

Directing the transfer of petroleum products from tank vehicles must be carefully planned in order to accurately account for the quantities delivered and issued, verify the quality of the products in transition, and to prevent spills.

This lesson covers the procedures for loading and unloading tank vehicles, their maintenance and gaging.

Terminal Learning Objective:

INTRODUCTION

The use of the tank vehicles in the Army is increasing because of the need for larger volumes of bulk fuels and rapid, uninterrupted distribution requirements for refueling military aircraft and vehicles.

PART A - TANK TRUCKS

The Army utilizes several different tank vehicles for use in refueling operations. Below is a description of these vehicles and their typical uses.

M49A2C Tank Truck. The M49A2C tank truck is mounted on a modified M45A2 chassis (2 1/2 ton). The truck has a multi-fuel engine with single front and rear dual tires. It is about 23 feet long, 8 feet wide and 7 2/3 feet high. TM 9-2320-209-10 (Operator's Manual for Truck, 2 1/2 ton 6x6 Gasoline Engine Models) gives details on this truck. The tank body is a stainless steel 1,200-gallon tank shell divided into two 600-gallon compartments. Each compartment has a manhole cover. One each five-pound carbon dioxide fire extinguisher is mounted on the left and right front of the vehicle. The rear equipment cabinet consists of a manifold, pump, filter/separator, discharge valve control and meter, water separator chamber, gage stick, grounding assembly, pump delivery line valve, gravity delivery line valve, filter/separator drain valve, and pressure gage. The pressure differential gage measures the effectiveness of the filter/separator. When the pressure differential between the inlet and outlet pressure is more than 20 psi, change the filter elements and the go/no go fuses. If pressure differential between the inlet and internal is 15 psi, replace filter elements only. Change only the go/no go fuses when the pressure differential reading is 15 psi between the internal and the outlet. A power take off shifting lever is located in the cab to the left side of driver seat. It operates the pump. The lever is moved backward to ENGAGE the pump. To DISENGAGE the pump, pull lever forward. The M49A2C is used for top and bottom loading, defueling aircraft, and pressure discharging.

M131A5C 5,000-Gallon Semitrailer. The M131A5C 5,000-gallon semitrailer (Figure 4-1) is the most commonly used fuel servicing tank semitrailer in the Army. It has 5,000-gallon capacity and weighs 12 tons. The entire vehicle is about 31 feet long, 8 feet wide, and 9 feet high. It is towed by a 5 ton, 6x6 tractor truck or like vehicle that has a fifth wheel. The semitrailer is used to carry and transfer fuel, service containers, and refuel ground vehicles. The semitrailer can travel cross-country at a reduced payload of 3,300 gallons (1,650 gallons in each tank compartment). It can fill or empty 3,000-, 10,000- or 50,000-gallon collapsible tanks. The vehicle can transfer product to or receive it from the fuel system supply point (FSSP). The stainless steel tank body is divided into two 2,500-gallon compartments, has a 20-inch manhole and filler cover assembly, with a vent valve and locking device, a discharge valve with screw assembly, and a drain pipe. A full marker gage that indicates when the tank is full is welded to each manhole cover. There is a walkway on top of the tank body with a slip-resistant steel grating. A ladder at the rear of the vehicle gives access to the manhole covers. The two compartments are connected by piping to the vehicle’s fuel delivery system. There is one equipment cabinet and a filter/separator on the curbside of the vehicle. The curbside equipment cabinet houses an auxiliary engine, pump, and battery. There are three hose tubes and one equipment cabinet on the roadside of the vehicle. The roadside equipment cabinet houses a meter, a 1 1/2-inch (0-55 GPM) dispensing assembly, 2 1/2-inch (225 GPM) dispensing assembly, filter/separator pressure gages, engine controls, fixed fire extinguisher system, portable fire extinguisher, and fuel handling controls. The three hose tubes are located directly above the roadside equipment cabinet. They hold three sections of suction hose and a gage stick. There is a door on both ends of the hose tubes. The auxiliary engine and pump assembly have a 2-cylinder, 4-cycle, air-cooled gasoline engine, a self-priming centrifugal pump and a 24-volt battery. The choke is on the left side of the engine. The engine controls are on the instrument panel located in the roadside equipment cabinet. These controls consist of a power panel switch, starter button, ignition switch, oil pressure, and voltage gage. The pump is connected to the auxiliary engine by bearing mounted shaft. A firewall separates the two items. The entire pumping system has a total capacity of 225 GPM. The filter/separator has three filtering stages. In the first stage 15 filter elements remove solid contaminants and coalesce any water in the fuel. In the second stage, five canisters separate the water from the fuel and let it drain into the filter/separator sump. Finally, there are 15 go/no go fuses as safety devices to shut off the flow of fuel if the other two stages allow water or solid contaminants to exceed a safe level. There are three of these fuses in each of the second-stage canisters. Other parts of the filter include an automatic dump valve, a manual drain valve, an emergency shutoff control, and three pressure gages. Any water collected in the filter/separator is removed by the automatic dump valve. This valve is operated by a float that rises in water and sinks in fuel. Drain water from the unit by opening the manual drain valve located at the bottom of the sump. Keep the valve open as long as water is running out. When fuel appears close the value. While product is flowing through the separator, check the pressure differential. A 300 GPM positive displacement meter is located on the right side of the roadside equipment cabinet. The meter counter registers up to 9,999 gallons. A knob on the side of the meter is used to reset the counter. Turn the knob clockwise until the counter is back to zero. The meter also has a totalizer which keeps a record of all issues. There are three dispensing assemblies on the M131A5C tank semitrailer. One assembly is made up of three 15-foot sections of 3-inch suction hose. These sections are stored in tubes located on the roadside of the vehicle. The other two assemblies are housed in the roadside equipment cabinet. The one on the left side of the cabinet is a 0-55 GPM dispensing assembly. It has a 50-foot section of 1 1/2-inch discharge hose, a hose reel, and a 1 1/2-inch nozzle with a bonding clip and a plug. The assembly on the right side of the cabinet is a 225 GPM dispensing assembly. It has a 50-foot section of 2 1/2-inch discharge hose, a hose reel and a 2 1/2-inch nozzle with bonding clip and plug. The 2 1/2-inch nozzle comes with two nozzle spouts. The standard 14-inch spout used for most fueling operations is normally attached to the nozzle. The 24-inch spout, is used only for defueling operations and is stored on the left side of the fire extinguisher, in the roadside equipment cabinet. Each dispensing assembly is controlled by a brake assembly and a rewind mechanism. There are two fusible link connections and two fusible nut connections on the semitrailer. The two fusible links are installed at the tank compartment discharge valves and the two fusible nuts are part of the operating lever assembly. If there is a fire in any of these places, the fusible links and nuts melt and close the tank compartment discharge valves.

Figure 4-1. M131A5C 5,000-gallon semitrailer.

M967 5,000-Gallon Semitrailer. The M967 5,000-gallon semitrailer is a bulk hauler with self-load/unload capability. It is designed for general highway and limited cross-country use. It has a 5,000-gallon capacity and weighs 13,000 pounds empty and 46,950 pounds full. The entire vehicle is about 31 feet long, 8 feet wide, 9 feet high. The semitrailer can be transported by a C-130 aircraft. It is also designed to be towed by a 5-ton, 6x6 truck tractor or similar vehicle equipped with a fifth wheel. It has a fording capability of 24 inches in salt or fresh water without major component preparation. TM 9-2320-356-12&P gives detailed information on this tank semitrailer. The stainless steel tank body of the M967 is constructed as one 5,000 gallon compartment with evenly distributed integral baffles. The compartment has pressure and vacuum vents and a manhole with locking device. There is a walkway on top of the tank body with a slip-resistant steel grating. A ladder at the front of the tank leads to the walkway. The tank compartment is connected by piping to the vehicle’s fuel receipt and delivery system. This system is mounted on the roadside of the vehicle. There is a pump and engine compartment, pump engine fuel tank, landing gear crank, and landing gear ground board on the curbside of the vehicle. There is also a hose trough, emergency valve shutoff, and two batteries on the curbside of the vehicle. There is a hose trough, landing gear ground box, toolbox, and control panel on the roadside of the vehicle. There is also a portable grounding rod and manifold valve on the roadside of the vehicle. The auxiliary engine and pump assembly are located in the curbside equipment cabinet. It has a 4-cylinder, 4-cycle, variable speed, air-cooled diesel engine and a self-priming, centrifugal 4-inch low pressure pump. The auxiliary engine is started by two 12-volt batteries connected in series. The batteries are located on the left side of the equipment cabinet. The engine controls are on the instrument panel located on the roadside of the vehicle. These controls include an engine preheater switch, engine throttle, and control panel light. The instrument panel also includes a voltmeter, tachometer, hour meter, oil pressure gage, fuel pressure gage, and pump pressure gage. The pump is connected to the auxiliary engine by a bearing-mounted shaft. A firewall separates the two items. The pumping system has a bulk fuel deliver rate of up to 600 GPM and a self-load rate of up to 300 GPM.

M969 5,000-Gallon Semitrailer. The M969 5000-gallon semitrailer is a fuel dispensing semitrailer used primarily for refueling ground vehicles. The M969 has the same bulk delivery and self load capabilities as the M967. It has a 5000-gallon capacity and weighs 15,000 pounds empty and 48,950 pounds full. The M969 has the same dimensions and can be towed and transported in the same manner as the M967 tank semitrailer. The tank body and auxiliary engine and pump assembly are identical to that of the M967. TM 9-2320-356-12&P gives detailed information on this tank semitrailer. In addition to the equipment included with the M967, the M969 includes equipment required for automotive refueling and limited aircraft refueling. This equipment is mounted on the sides of the vehicles. There is a filter/separator, pump and engine compartment, engine fuel tank, landing gear crank, and landing gear ground board on the curbside of the vehicle. There is also an emergency valve shutoff, hose trough, and battery compartment for two batteries on the curbside of the vehicle. There is a hose trough, portable grounding rod, landing gear ground board, toolbox, control panel, manifold assembly, and hose reel cabinet on the roadside of the vehicle. The filter/separator is rated at 300 GPM and 15 psi. It has three filtering stages. In the first stage, 15-filter elements remove solid particles and coalesce any water in the fuel. In the second stage, five canisters separate the water from the fuel and let it drain into the filter/separator sump. Finally, 15 go/no go fuses act as safety devices to shut off the flow of fuel if the other two stages allow water to exceed a safe level. Three of these fuses are in each of the second stage elements. Other parts of the filter/separator include an automatic drain valve, a manual drain valve, and a pressure gage. When water in the filter sump reaches a certain level, the water is removed by the automatic drain valve. This valve is operated by a float which rises in water and sinks in fuel. As water enters the filter sump the float rises. When the float rises to a certain level, a valve opens in the drain valve assembly allowing pump pressure to be applied to a diaphragm valve. The opening of diaphragm valves causes the automatic drain valve to open, allowing the water to drain. As the water is being drained, fuel flow is continued. If water enters the sump faster than the automatic drain valve can carry it away, or if the filter elements fail, the go/no go fuses stop the flow of fuel completely. The pressure gage is located on the instrument panel in the roadside equipment cabinet. It indicates the amount of restriction in the filter/separator. Two 100 GPM meters are located in the roadside equipment cabinet of the M969. The meter counter registers up to 9,999 gallons. To reset the count to zero, push in the meter reset knob on the side of the meter and turn clockwise. The meter may also be used during defueling operations. If any trouble with the meter occurs, take the vehicle to organizational maintenance. The utility meter must also be checked for accuracy to make sure the correct amount of fuel is being delivered. There are three dispensing assemblies on the M969 tank semitrailer. One assembly is made up of three 14-foot sections of 4-inch suction hose. These sections are stored in troughs located on both sides of the vehicle. This assembly has a bulk deliver rate of up to 600 GPM and a self-load rate of up to 300 GPM. The other two assemblies are housed in the roadside equipment cabinet. Each of these dispensing assemblies includes a meter, a hose reel with electric rewind, 50 feet of 1 1/4-inch dispensing hose, and a dispensing nozzle. Flow rate for metered delivery of fuel (gasoline or diesel) is up to 600 GPM, through one nozzle only or through both nozzles at the same time.

M970 5,000-Gallon Semitrailer. The M970 5,000-gallon semitrailer is a fuel dispensing semitrailer used primarily for under-wing/over-wing refueling of aircraft. It has a 5,000-gallon capacity and weighs 15,200 pounds empty and 49,150 pounds full. The M970 has a bulk delivery rate up to 600 GPM and a self-load rate up to 300 GPM. It is designed to be towed by a 5 ton, 6x6 truck or similar vehicle equipped with a fifth wheel. The tank body is stainless steel and is constructed as one 5,000-gallon compartment with evenly distributed integral baffles. The compartment has pressure and vacuum vents and a manhole with locking device. The tank compartment is connected by piping to the vehicles fuel receipt and delivery system. In the curbside cabinet there is a filter/separator, two 12-volt batteries, pump and engine compartment, engine fuel tank, landing gear control, and emergency valve shutoff. The roadside cabinet houses the landing gear ground board, recirculation fitting, portable grounding rod, toolbox, manifold assembly, control and instrument panel, hose reel cabinet. In the hose reel cabinet you have 1 1/2-inch hose reel and hose, 2 1/2-inch hose reel and hose, and 300 GPM meter assembly.

M978 Heavy Extended Mobility Tactical Truck (HEMTT) Tanker. The M978 HEMTT tanker (Figure 4-2) is used for refueling wheeled and track vehicles, and aircraft, which on today’s modern battlefield, are more mobile than ever before. The M978 comes equipped with two hose reels, each containing 50 feet of 1 1/2 inch hose, with service nozzle of 2 1/2 inch in diameter and a pressure differential gage which indicates a dirty or clean filter/separator. There are 18 elements and 18 canisters. The vehicle can operate in temperatures from 25 to 120 degrees Fahrenheit, ford water up to 48 inches deep for 5 minutes without damage or requiring maintenance before operation can continue, maintain a speed of 25 MPH on a 3 percent grade with full trailer (100,000 lbs) and 40 MPH on a 3 percent grade vehicle only (60,000 lbs), maintain speed up to 55 MPH while operating at full load without a trailer on good, level road, and start and climb a 30 percent grade fully loaded with a trailer or start and climb a 60 percent grade fully loaded without a trailer. The normal operating range for the transmission, eight wheel drive vehicle is 300 miles, based on 159 gallons of fuel. The M978 can be utilized for self-loading (filtered or nonfiltered), recirculation, bulk delivery filtered, dispensing using over wing/CCR nozzle, and defueling. The M978 can also be used for aircraft refueling operations by utilizing the HEMTT Tanker Aircraft Refueling System (HTARS). The HTARS kit, it’s components, use, and operation are discussed in the following lesson.

Figure 4-2. M978 HEMTT tanker.

Vapor Recovery System. The vapor recovery system can be installed on all models of tank semi-trailers, and is required in certain ecological areas. The system allows a fuel depot to collect or recover the vapors and gases that are present during the loading operation. Vapors can also be recycled back to the semitrailer through the recovery system during the loading operation. This system consists of a vapor-tight line running from the sealed hood on the emergency valve vent (directly behind the manhole cover) to the rear of the tank. The rollover rail on the roadside of the semitrailer is used as part of the line. The adapter on the end of the line is compatible with the 4-inch quick-disconnect, vapor recovery connections at a majority of fuel depots.

Tank and Pump Unit. The tank and pump unit consists of a 50-GPM pumping assembly, two 500- or 600-gallon aluminum tanks, and related equipment. The unit is designed to be transported on the 5-ton, 6X6 cargo truck due to the fact that when the unit is filled with fuel it exceeds the load limit of the 2 ½-ton cargo truck. The unit can be used to fill and empty 500- and 600-gallon collapsible drums, 55-gallon drums, and 5-gallon cans; temporarily store product; refuel ground vehicles; and replace or supplement special purpose vehicles. The unit may also be used to fuel aircraft if no other aircraft refueling equipment is available.

There are several standard models of the tank and pump unit. The main differences are in their pumps, filter/separators, manifolds, and hoses. TM 10-4930-204-15 (Operator's Organizational Direct Support General Support, and Depot Maintenance Manual) gives details on installing, operating, and maintaining the different models of the unit. A description of the various components is provided as follows:

Tanks. The tank shells have a manhole assembly, pump-port drain plug, and discharge valve assembly. Controls for the discharge valve are on the top of the tanks. The discharge valve outlet is at the bottom rear of the tank, and the drain plug is at the bottom front. A baffle inside the shell helps keep down the surge of the product during transport. Two lifting rings are attached to the top of each end of the shell to make handling easier. Tie downs are provided for securing the tanks in the vehicle bed.

Pump. The pump is a 50 GPM, self-priming, centrifugal pump. The impeller is screwed on the extension of the engine crankshaft. The engine is a 1-cylinder, 4-cycle, air-cooled, hand cranked engine. Some models have 2-cylinder, 4-cycle, overhead-valve, air-cooled engines. A radio-shielded magneto supplies the ignition spark, and a governor controls the engine speed by varying the throttle openings to suit pump loads. The gasoline tanks hold one gallon. The pump and engine are mounted on a common base so that they can be easily removed for servicing and can be used in other pumping operations.

Filter/Separator. The filter/separator is a vertical, 50 GPM capacity unit with four standard canisters and filter elements. The tank and pump unit can be used to refuel aircraft because the filter/separator qualify under military specification MIL-F-8901C.

Manifold. The manifold controls the flow of product to the suction side of the pump. Two quick couplers provide connections or inlets for the tank suction lines. The product flows from either or both tanks to the pump suction through the manifold outlet and a section of hose. Some models have a discharge hose that runs from the filter/separator to the manifold and product can be discharged from the manifold outlet when the three-way valve issued to close off the suction side. Other models use the only manifold for suction.

Hose Reels. The dispensing hoses are stored on two hose reels each with a recoil tension spring. A 40-foot length of 1 1/2-inch non-collapsible discharge hose is used on each reel. Product from the filter/separator enters through a pipe at the hub of the reel and is discharged through the hoses.

Ground Reel. A ground reel is attached to the frame of the pumping assembly so that the tank and pump unit can be grounded. One section of the ground wire must be clipped to a ground rod near the tank and pump unit before the other section is connected to the vehicle being fueled.

Metering Kit. The metering kit consists of a meter, hose assembly, couplers, cap screws, and washers. The kit is used with pumping assemblies on all tank and pump units.

Other Items. Other items issued with the pumping assembly are a drum-unloaded suction stub for emptying 55-gallon drums, two dispensing nozzles, a starter rope, a carbon dioxide fire extinguisher, and tie down assemblies. If the nozzles have lock-on, latch-open devices, the devices must be fixed so that they must be held open by hand and attended at all times.

PART B - GAGING PETROLEUM TANK VEHICLES

Each tank has its own gage stick. It may be made of wood or metal depending on the type of vehicle. It is important that you keep the stick protected from the elements whenever not in use. The gage stick is usually graduated into 25-gallon divisions. Before gaging any type of vehicle, bond and ground the tank vehicle and ground yourself from static electricity by touching a bare hand to the tank shell. Do not wear headgear or loose items when you are on top of the tank vehicles. Never gage during an electric storm. Position the fire extinguisher within 10 to 15 feet of the tank vehicle. Verify the shipping document for kind of fuel in the tank vehicle. Insert the thermometer as soon as you open the hatch. (If quantity is less than 3,500 gallons, it is not necessary to take the temperature). Gage the compartment. Take all-level sample. Measure the API gravity of the sample and record it on the gage work sheet. Correct the volume to 60 degrees Fahrenheit if required.

Practice Exercise