Center Pivot Maintenance

The interruption of water application by irrigation equipment can cause great and serious losses to producers, depending on the stage of the irrigated crop. Paying attention to operation and maintenance procedures prevents these losses and prevents others.

A huge disruption to irrigators occurs when mechanized irrigation equipment suffers a malfunction, which causes the interruption of water application, mainly during critical periods of crop development. This problem is aggravated in high frequency systems, such as the central pivot, which apply reduced water levels, sufficient to replace daily consumption or a few days. Therefore, there is not a significant amount of water available stored in the soil, which could satisfy water demand during the period in which the system is inoperative, especially in sandier soils, with lower water retention capacity available to crops.

For reduce the possibility of accidents and operational interruptions in central pivot sprinkler mechanized irrigation equipment is recommended carefully observe some procedures related to its operation and maintenance.

During lightning storms electrical equipment, the proximity of people to the equipment must be avoided, as that it constitutes an efficient grounding system and, in flat areas, represents a high point in the field, which can favor the attraction of lightning. Of the same Therefore, access by children or irresponsible people to the equipment must be prohibited. It is common to underestimate the accidents caused by intermittent operation and Reduced travel speeds can result in uninformed people.

It is also necessary to be aware vehicles and other materials that may obstruct the vehicle's travel paths. equipment. The torque available at the driving wheels is generally sufficient to climb obstacles of varying dimensions and cause great damage. Having the alternative of moving the equipment to other areas is important to avoid its traction through channels or surface pipes, overhead lines transmission of electrical energy, buildings and other obstacles that could damage equipment or cause accidents. Power transmission lines electrical in areas close to the equipment's reach must be buried, providing adequate signage of its location.

Water applied by a pivot central should not reach rural, municipal roads and highways, with or without paving, due to the risk of causing serious traffic accidents. It should Also avoid contact with water from sprinklers that operate at higher pressures, such as the hydraulic cannons installed at the end of the lateral lines and, especially, when there are dissolved chemicals in the water. In this case, these products must not exceed the cultivated area.

Engines and generators must operate within the limits recommended by the manufacturers. Both speeds are very Reduced, as well as excessive, increase wear and shorten the useful life of these components. Periodically, it is necessary to assess whether there are nuts and bolts loose or missing and other evidence that could lead to a possible structural collapse.

The accuracy of the pressure gauges also must be systematically evaluated, mainly in systems that do not use pressure regulators on sprinklers. It is also regularly necessary to walk through the equipment to assess the operational condition of the water applicators (sprinklers, sprayers, etc.) trying to unblock or replace any damaged units. A blocked nozzle 400m away distance from the pivot point can compromise the productivity of 1,5 hectares of the culture. It is very important to note that each nozzle is sized specifically for his position on the sideline, i.e. the replacement of nozzles must be made in accordance with the previously made sizing.

Another important procedure for system maintenance is to observe, notably, in the most distant parts from the central point, the occurrence of superficial runoff caused by an excessive reason of water application.

It's not difficult, although laborious, accurately determine the uniformity of water distribution in a central pivot. The test involves installing a radial line of collectors, spaced every 10 or 20m, depending on the size of the equipment, covering the entire wetting radius. Choose a position for the equipment that corresponds to the average operating condition in the irrigated area. Not having pressure regulators installed on sprinklers, it is recommended to carry out tests additional in positions with greater slope and slope of the irrigated area.

The procedure can provide a satisfactory indication of how the quantity of water foreseen in the design is being distributed in the irrigated area and is not intended to calculate the statistical aspects of this distribution. It is necessary to consider that the sprinklers further away from the center are responsible for irrigating areas proportionally larger. There is great variability in quantities collected, it is important to identify the corresponding sprinklers to promote a more careful dimensional and operational assessment of them.

The operational condition of the station pumping system, inspecting the readings of electrical indicators, such as the voltage and amperage must also be evaluated regularly.

For the procedures of maintenance, it is necessary to strictly follow the program recommended by the manufacturer. To this end, the person responsible must be familiar with the operational and maintenance procedures, as well as recommendations for your safety while carrying out these procedures.

The energy electrical system, responsible for pumping and operating the system, must be off before starting equipment maintenance. In general, there is a switch available on the control panel that can be activated by the person responsible for maintenance service. During operational tests it is important to avoid contact of hands and clothing with moving parts of the equipment, which can cause serious accidents. Metal ladders must not be used to access the equipment during maintenance work, thus avoiding the risk of electrical discharges. Preferably use portable elevators with side protection on the platform, or stairs constructed with material insulating.

In electrical system repairs, all three phases must be individually grounded. These specialized services must be performed in accordance with specifications from the manufacturer. Repairs or maintenance on high or low voltage components must always be carried out by qualified professionals. It is recommended promote a final inspection by a competent technician, to assess safety and the condition of the connections, in accordance with the concessionaire's requirements by the electrical energy supply, before restarting the operation of the equipment.

Other important factor is to never use gasoline or alcohol as cleaning agents. cleaning, as they may eventually ignite from static electricity. generated in the equipment. If a short circuit is detected in the electrical system, do not there must be contact with the equipment and a competent professional must be triggered to perform the repair.

Drain the gearbox, examine its components, looking for possible replacements damaged elements and the lubricant used, in addition to examining the condition joints, pivot point, alignment, pressure and pressure controllers. Tire conditions are also aspects that need special attention.

Edmar José Scaloppi, FCA/UNESP

 Article published in issue 155 of Cultivar Máquinas.