Advantages of fueling and lubricating with a convoy truck

Mobile supply and lubrication on rural and forestry properties makes life easier for operators, in addition to ensuring less time lost in stops and travel.

The cultivated areas in Brazil are different in terms of size, topography and soil characteristics, and it is common for there to be large distances between work areas and service stations on properties. The latter, generally located at headquarters, show that moving certain machines for supply and lubrication results in higher costs or is technically unfeasible.

Generally, machines that are difficult to move and have high operating costs require service at the work front, minimizing downtime for greater operational efficiency.

In order to meet these needs in the field, there are convoy vehicles, popularly known as “melosa”. These are units mounted on chassis or bodies, equipped with the necessary resources for both fueling and lubrication.

Fueling and lubrication activities can be organized and/or carried out by the machine operator or the train vehicle team. These activities depend on factors such as the number of machines to be lubricated and filled, distance between the work fronts and the property headquarters, the operator's technical capacity for lubrication and supply activities, availability of equipment to carry out the activities and risks of contamination. .

Although fueling and lubrication costs are lower when carried out by the machine operator, this option has disadvantages, such as greater likelihood of waste, environmental contamination, errors in data recording and the quantity supplied.

However, the use of trains makes it possible to carry out supply and lubrication operations simultaneously (increasing productivity), and reducing the risks of contamination and waste. It is also known that the feasibility of providing specific training to train staff (driver and oiler) is greater than training all operators.

The evolution of train vehicles occurred simultaneously with the increase in agricultural mechanization in the country. The insertion of machines with high technology on board highlighted the need to restructure the maintenance, lubrication and supply processes, proving to rural entrepreneurs that improvised processes no longer reach the necessary results.

SPECIFICATIONS

The convoy can be specific for supply or just for lubrication, and can also have both functions combined in the same vehicle. This mixed train may have tanks for fuel (usually diesel, but also gasoline, alcohol, kerosene and aviation gasoline), greases, lubricants, filter elements, compressed air (for inflating tires, cleaning parts, radiators and filters). air), water and cooling additives. They are normally sized according to the needs of each case.

The introduction of electronic engines, which meet Proconve P7 and MAR-I resolution, exposed the need for reservoirs also for diesel S-10 (sulfur content of 10mg/kg) and Arla-32. This substance combines treated water and urea, being a reagent used with SCR technology – Selective Catalytic Reduction or Selective Catalytic Reduction, which chemically reduces the volume of NOx emitted by diesel engines. Therefore, if the property has vehicles that require these inputs, and are supplied by the train, these reservoirs must be provided.

The volumetric capacity and the number of lubricant reservoirs are sized in relation to the number of machines served (for replacement or oil changes during the period), having a direct relationship with the hours worked. The choice of the size of the fuel tanks must consider the volume demanded by the machines during the period. It is understood that the train can be refueled several times a day (a more practical and faster supply than lubricants), and subsequently move on to other service fronts. A tank with full daily supply capacity is not necessary.

The train must have protection against the weather and can be open, semi-open or closed. Many manufacturers, for safety and environmental reasons, no longer offer open and semi-open trains in their portfolio due to the greater risk of contamination and less durability. Therefore, the most requested trains are armored and modular ones. This second one facilitates configurations at the time of purchase, being able to add the number of modules according to the specific need.

This configuration favors ergonomics, allowing operators to access the module with hose reels and meters at ground level. The other modules contain reservoirs for fuel, lubricating oils, grease, used oil, compressed air and others (in order to house used tools, accessories and filters). The modular system is also safer, as the fuel tank tends to be located in the center, protected from collisions by the other modules.

Hose reels can be retracted manually or by spring. As the hoses are extensive, to improve work in the field, it is recommended to always use retractable spring-loaded reels, to avoid contact between the hose and the ground, reducing the possibility of contamination. 

The arrangement of the reels in the train can be lateral - commonly used in mining and/or agroforestry areas. It can also be rear - applied to services with machines on highways, allowing the positioning of the convoy to reduce the width of the group, facilitating the flow of other vehicles.

LUBRICANT PROPULSION

To supply the train's lubricating oil tanks, three forms of propulsion are used: pneumatic, pressurized and hydraulic.

Pneumatic propulsion operates through a pump installed in the lubricant drums or reservoirs, being moved by compressed air and delivering lubricant flow rates of up to 15L/minute. This value is insufficient for use in properties with a large number of machines and equipment or for many daily services. It is the most used system for grease propulsion, as the low flow rate is desirable to facilitate dosing into the grease fittings, in order to avoid waste and contamination.

Pressurized propulsion performs pressure supply, as shown schematically in Figure 1. When supply is by positive pressure, it is used to supply machines. When the system is negative pressure (Venturi effect) it is used to remove used oil from the machine or to refill the train's reservoirs. It is important that the compressed air injected into the reservoirs is filtered and free from moisture.

This system does not require pumps and other components, resulting in lower acquisition costs and simple maintenance. It is the model most required by the sugar and alcohol industries, agroforestry and construction sites, as it operates with a flow rate of up to 25L/minute.

The hydraulic system operates with gear pumps, being driven by hydraulic motors, providing flow rates from 40L/minute to 90L/minute. However, it is the most valuable of the three models, generally used in mining works and large infrastructure projects. 

VEHICLE SIZING

The selection of the vehicle that will transport the train must be carried out after sizing the reservoirs. It must be estimated for the most adverse conditions encountered, ensuring uninterrupted operation, taking into account road dimensions, soil types, topography (flat to hilly) and rainy periods (requiring traction on all axles), temperature (if very low or high) and conditions of the service fronts.

With this data, it is possible to choose the type of chassis (according to load and usage regime), power, number of axles (according to Law 9.503), ease of maneuvering and types of tires.

Depending on the size, the vehicle can be a truck, a trailer pulled by a tractor or even a pickup truck, the latter of which can also transport a small train on its body. The trailers can have their equipment driven by a tractor's power take-off (TDP) or by a stationary engine. Pickup trucks, in addition to the possibility of a stationary engine, can have their bodies powered by the vehicle's battery.

Furthermore, it is common and frequent to use pickup trucks that carry fuel drums, lubricants (in their original packaging), grease pumps, water containers, among other items and tools, carrying out the activities of a convoy.

QUICK CONNECTIONS

An alternative found on several trains are quick coupling systems. Such systems work by fitting the hose directly to the fuel supply or lubricant drain nozzle, reducing the use of auxiliary devices such as funnels, trays, tow and cloths. It is important that the connections used in this equipment avoid any type of leak as much as possible.

Gains can be obtained, such as shorter service time, elimination of lubricant splashes, reduction of the chances of operators being burned by the oils removed, direct aspiration of reservoirs and hermetic fluid exchange.

When collecting used oil, the hose is connected directly to the crankcase or drain containers. It is important that the same new oil supply hose is not used to remove used oil, to avoid contamination.

HIGH-FLOW FUEL SUPPLY

Conventional supply pumps have a flow range of 50L/minute to 150L/minute. With the advent of quick-connect nozzles, it was possible to use high-flow systems, which have a capacity of up to 500L/minute. If a machine with a 1.000L fuel tank is considered, the difference in fueling time can reach up to 18 minutes. This gain in time results in a greater quantity of supplies that the train will be able to carry out daily, less downtime, contributing to operational efficiency.

AUTOMATED RECORDS

Measuring systems can be analog or digital. They have the advantage of instantaneous supply control, memorizing the quantities moved daily, in addition to enabling integration with data collectors.

Choosing the best fluid transfer control technology results in greater accuracy in recording the volumes of fuel, lubricating oils and grease filled into the machines.

With the evolution of technologies embedded in machines, it is common to find increasingly sophisticated systems. This makes direct communication between agricultural machines and control centers possible. They instantly inform operations times, operational rhythm, fuel consumption, maintenance period, among other information.

Automated recording systems are responsible not only for storing information, but also for issuing supply reports. Such systems have technologies that lock the fueling mechanism, preventing the operator from filling or lubricating the wrong machine.

All machines have their technical data (tank volume, consumption, types of fluids, among others), supply and lubrication history registered in the system. This allows the train to identify the machines and the period in which they need to be lubricated and fueled - limiting the quantity supplied -, thus preventing waste and theft, as fuels are products that are easy to sell in clandestine markets.

Recording lubrication and fueling data manually allows for gaps in process security. It allows for diversions or waste of fuel, in addition to low reliability, as the notes may be incorrect, illegible or lost.

SECURITY

To carry out activities with the convoy vehicle, it is necessary to observe the rules that cover: the transport of dangerous products, those relating to non-contamination of the environment, operation and work safety and the storage of flammable liquids. 

Rovian Bertinatto, William Vaz Belinazzo, Mario Fernando de Mello, Sabrina Dalla Corte Bellochio, Catize Brandelero, Valmir Werner, Nema/CCR - UFSM

Article published in issue 169 of Cultivar Máquinas